Substitute for: PC Q-Code X X X X X Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017 Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date Product W-2S Description 2-S Dual Fuel Engine Safety Concept Made 27.06.2014 S. Arp Main Drw. Page 1 / 63 Material ID PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group 9727 Drawing ID DAAD046594 Rev F Appd 10.11.2017 S. Goranov T_PC-Drawing_portrait | Release: 1.30 (10/25/2017) Copyright WinGD. All rights reserved. By taking possession of the drawing, the recipient recognizes and honors these rights. Neither the whole nor any part of this drawing may be used in any way for construction, fabrication, marketing or any other purpose nor copied in any way nor made accessible to third parties without the previous written consent of WinGD. 2-STROKE DUAL FUEL ENGINE SAFETY CONCEPT Rev Date Made Appd Description A 2014-06-27 SAR SGO Major amendments B 2014-09-08 SAR SGO Updates C 2015-06-18 SAR SGO Updates D 2016-05-10 JGA SGO Updates based on class comments. Focus of safety measures on use of natural gas as fuel E 2017-02-08 HHU SGO Fuel sharing and Dynamic Combustion Control F 2017-11-09 TFL SGO General updates and clarifications Document structure and format updated
Transcript
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
1 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Figure 2-1: Lean burn with pilot ignition ........................................................................... 12 Figure 2-2: Lean burn operation window ......................................................................... 13 Figure 2-3: Gas admission valve ..................................................................................... 14 Figure 2-4: Example of double-wall gas piping on WinGD 6RT-flex50DF ........................ 15 Figure 2-5: New piping design of gas supply pipe to engine ............................................ 16 Figure 2-6: Double-wall gas piping around gas admission valve and gas manifold ......... 16 Figure 2-7: GVU Human Machine Interface (HMI)........................................................... 18 Figure 2-8: GVU-ED™ .................................................................................................... 19 Figure 2-9: GVU-OD™ .................................................................................................... 19 Figure 2-10: GVU-OD™ Installation ................................................................................ 21 Figure 2-11: GVU purging and venting sequence ........................................................... 22 Figure 2-12: Preliminary sketch of iGPR layout ............................................................... 24 Figure 2-13: Inerting of engine gas rail ............................................................................ 25 Figure 2-14: Inerting of gas supply pipe to iGPR ............................................................. 26 Figure 2-15: Pilot fuel high-pressure ............................................................................... 27 Figure 2-16: External exhaust system ............................................................................. 28 Figure 2-17: Exhaust ventilation ...................................................................................... 29 Figure 2-18: Flow chart exhaust ventilation procedure .................................................... 30 Figure 2-19: LP SCR system with temperature controlled arrangement .......................... 31 Figure 2-20: HP SCR system arrangement ..................................................................... 32 Figure 2-21: Exhaust gas waste gate (EWG) installation................................................. 33 Figure 2-22: Simplified control system layout with either GVU or iGPR installation ......... 33 Figure 2-23: Signal flow diagram between ECS and external systems for GVU .............. 34 Figure 2-24: Preliminary signal flow diagram between ECS and external systems for iGPR ............................................................................................................................... 35 Figure 2-25: Overview of fuel transfers ........................................................................... 37 Figure 2-26: Engine stop from gas mode ........................................................................ 39 Figure 2-27: Cancellable shutdown sequence of DF-engine from gas mode ................... 40 Figure 2-28: Non-cancellable shutdown and emergency stop sequence of DF-engine from gas mode ........................................................................................................................ 41 Figure 2-29: Transfer from diesel to gas mode ................................................................ 42 Figure 2-30: Transfer from gas to diesel mode ................................................................ 43 Figure 3-1: Example of gas detector positioning in engine room, gas supply system and engine with GVU ............................................................................................................. 47 Figure 3-2: Cylinder unit and piston underside (hazardous zones) .................................. 49 Figure 3-3: Fuel gas system (hazardous zones) ............................................................. 49 Figure 3-4: Gas Valve Unit (hazardous zone) ................................................................. 50 Figure 3-5: External exhaust gas system (hazardous zone) ............................................ 50 Figure 4-1: LT cooling water system layout for twin-engine installation ........................... 53 Figure 4-2: Cylinder LO system layout with iCAT for twin-engine installation .................. 54 Figure 5-1: Misfiring Monitoring Concept ......................................................................... 56
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
8 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Table 5-1: Cause and effect chart in gas and fuel sharing mode ..................................... 56 Table 5-2: Sensors connected to ESS: Failure monitoring and actions during operation with fuel gas .................................................................................................................... 58 Table 5-3: Sensors connected to AMS: Failure monitoring and actions during operation with fuel gas .................................................................................................................... 58 Table 5-4: Sensors connected to ECS: Failure monitoring and actions during operation during operation with fuel gas ......................................................................................... 60 Table 5-5: Sensors connected to ECS: Failure monitoring and actions during operation with fuel gas (continued) ................................................................................................. 61 Table 5-6: Sensors connected to ECS: Failure monitoring and actions during operation with fuel gas (continued) ................................................................................................. 62
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
9 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
The purpose of this document is to describe the engine room arrangement and safety functions of Dual Fuel (DF) engine applications. Only items that are specifically related to gas safety, and differ from diesel engine application, are handled in this document. The DF-engine itself is classified. The present document contains only information that is necessary to understand the function and safety features of the DF-engine.
The WinGD 2-stroke DF-engine is a long-stroke crosshead engine. The DF-engine can be operated using either gas or liquid fuel. To enable this, the engine is equipped with an electronically controlled diesel fuel injection system, but also with electronically controlled gas and pilot fuel injection systems.
The DF-engine is designed to operate on fuel gas at the same safety level as when using diesel fuel. The safety concept is based on early detection of problems that could lead to a hazard, followed by immediate actions to prevent the situation from becoming dangerous. Depending on the machinery configuration and the type of problem detected, the safety system can initiate alarm, trip to diesel and induce slowdown or shutdown of the DF-engine.
All systems must be built in accordance with the requirements of both IMO and Classification Society. Accordingly, the content of this document is aligned with rules and regulations from IMO’s IGC and IGF codes and the classification societies. A Failure Mode and Effect Analysis (FMEA) has been performed. The FMEA document itself is WinGD intellectual property and can therefore not be disclosed to any third party.
DF-engines on board seagoing vessels use the cargo LNG or LNG stored in a separate / additional gas tank in gaseous phase as their primary fuel. This document covers the gas related matters, i.e. the systems that are different from, or in addition to, a standard diesel engine. The standard diesel systems and the diesel operation safety are not described here.
The scope of the document encompasses the systems to be installed in the engine room up to the manual shut-off valve outside the engine room, which are needed to operate the DF engine in gas mode.
Documentation referred to in the text, such as arrangement drawings, flow sheets, calculations, etc. are included in appendixes attached to this document.
The special features and safety arrangements of DF-engine installations shall be included in the ship’s operational documentation, and the crew must be trained accordingly.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
12 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
2 Description of Dual Fuel engine and related systems
The purpose of this chapter is to describe the WinGD 2-stroke DF-engine general operating principle and components related to gas operation. Also, components and functions of DF-engine auxiliary systems related to gas operation and gas safety are described.
2.1 The lean burn concept – Operating principle in gas mode
In gas mode, the DF-engine runs as a lean burn engine where the ignition is initiated by injecting a small amount of pilot diesel oil, giving a high-energy ignition source for the main fuel charge (gas-air mixture) in the cylinder (Figure 2-1).
With the lean fuel mixture, it is possible to achieve excellent engine characteristics regarding output, efficiency and emissions. A lean air-fuel mixture is also utilised to avoid pre-ignition, knocking or excessively fast combustion. However, at high loads the misfiring limit is nearing the knocking limit, which means that the available operating window is narrowed (Figure 2-2).
Figure 2-1: Lean burn with pilot ignition
However, by controlling the combustion process individually in each cylinder, the optimal operating window and performance can be maintained for all conditions. The DF-engine facilitates individual cylinder combustion control, which makes it possible to obtain optimal operating performance at conditions where gas quality, ambient temperature, etc. vary.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
13 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
The engine is equipped with a misfiring and knock detection system which monitors individual cylinders during gas operation. This ensures that the engine control system immediately trips to diesel operation if excessive misfiring or heavy knock is detected.
The system is active when fuel gas is used including transfers and can therefore immediately detect a non-igniting cylinder.
2.1.2 Dynamic Combustion Control
The Dynamic Combustion Control (DCC) function ensures that even under hot ambient suction conditions and/or when running on gas with a low Methane Number, the full rated engine power can be achieved in gas mode. If critical cylinder pressures are reached at high engine loads, a small additional quantity of liquid fuel is injected with the main fuel injectors.
At activation of DCC is always LFO to use. During DCC operation the liquid fuel used can be changed from LFO to HFO and vice versa. To continue running in gas mode without DCC when the function is deactivated, the liquid fuel system needs to operate on LFO so that no HFO remains in the liquid fuel injection system for longer period without consumption.
2.2 Fuel gas system
2.2.1 General description
The fuel gas system consists of the external fuel gas supply system (FGSS), gas pressure control (GVU or iGPR) and engine internal gas system. The fuel gas systems vary to some extent depending on DF-engine type and specific ship installation, but the main principles regarding structure, operation and safety are the same.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
14 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
The main components of the engine internal gas supply system are vent valves on the engine, shut-off valves, gas supply pipes and gas admission valves.
2.2.2.1 Gas admission valve
The gas admission valves are controlled by the Engine Control System (ECS) to regulate the engine speed and power by controlling the amount of gas fed to each cylinder. The valves are located so that gas is fed into the cylinder liner (located directly at the cylinder liner below the mid-stroke). The gas is mixed with combustion air only in the cylinder liner (Figure 2-3). The gas admission timing is set so that the cylinder will be scavenged without unburned gas escaping directly from the inlet to the exhaust.
The gas admission valve is an electro-hydraulically actuated valve. The valve is closed by a spring when no servo oil pressure is available. A stroke sensor mounted on the gas admission valve provides feedback to the CCM of each individual cycle. As such, the engine control system can immediately release a gas trip in case a valve shows delayed closing or is stuck open for some reason and performs corrections of gas admission timing and duration.
A sealing oil system prevents gas from flowing into the servo oil system and ensures lubrication of the valve stem.
The gas admission valve features a single-wall housing, which is pressure tested after manufacturing.
Figure 2-3: Gas admission valve
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
15 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
The gas is supplied to the engine through a double-wall manifold pipe running either side of the engine (fuel and exhaust side), branching with individual flexible feed pipes to the gas admission valves on each cylinder (see Figure 2-4). Two shut-off valves are located upstream of the admission valves and provide isolation / protection for the engine (see Figure 2-5).
The air inlet to the supply piping annular space is arranged on the engine, in close proximity to the gas vent line. If requested by the Classification Society, the shipyard can continue the pipe and lead it to the outside. In this case the pipe must be led to a gas-safe area outside the engine room.
The gas piping ventilation is described in chapter 3.5.2.
All gas pipes on the engine are depressurised, when not running on gas. Before any maintenance work is carried out, the system must be purged with inert gas, typically nitrogen. All pipes are pressure tested after assembling and tightness of the gas system is constantly monitored with the double-wall piping concept, where a possible gas leakage would be detected by the gas concentration sensor in the annular space of the piping.
2.2.2.3 Shut-off and vent valves
Shut-off and vent valves are placed in the main gas line on the engine (see Figure 2-5). The shut-off valves isolate the engine from the gas supply. This ensures that no gas will be delivered to the engine. The vent valves on the engine can quickly release the gas pressure in the engine’s gas pipes to ensure a gas pressure free engine as soon as the gas operation is stopped. Every section of gas piping can be depressurised to allow maintenance.
The fact that the shut-off valves are of normally-closed type and the vent valves of normally-open type ensures that the gas supply is immediately stopped in case of a power black-out, and the pipes are immediately depressurized.
Figure 2-4: Example of double-wall gas piping on WinGD 6RT-flex50DF
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
16 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Figure 2-5: New piping design of gas supply pipe to engine
Figure 2-6: Double-wall gas piping around gas admission valve and gas manifold
2.2.3 Gas Valve Unit and external fuel gas supply system
The fuel gas pressure can be controlled either by an external Gas Valve Unit (GVU) or integrated Gas Pressure Regulation (iGPR). This chapter describes the execution with GVU.
2.2.3.1 General description of external fuel gas supply system
The external fuel gas supply system upstream of the GVU consists of gas supply piping and pressurised gas supply. Only some general notes about the gas supply piping and the master fuel gas valve are given in this document.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
17 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
If gas supply piping between the gas storage area and the engine room is led through other enclosed spaces, the piping must be double-walled or enclosed in a ventilated duct. The duct will be equipped with gas detection and ventilation flow/under pressure detection.
Shut-off valve
The shut-off valve before gas pressure control is open in normal operation and used to shut off the gas supply to the engine room. This valve is controlled by the gas safety system of the ship. The shut-off valve can be closed from the DF-engine room, engine control room and wheelhouse.
The valve shall also close automatically in several other cases of normal engine operation and as reaction of detected failures as demanded by class rules.
2.2.3.2 General description of Wärtsilä Gas Valve Unit
Introduction
WinGD 2-stroke Dual Fuel engines require precise regulation of fuel gas pressure with a timely response to changing load conditions. For this purpose, Wärtsilä has developed the Gas Valve Unit (GVU), which encompasses all performance and safety requirements associated with 2-stroke DF Engine applications. There are two versions of GVU available:
GVU-ED™ (Enclosed Design): The enclosed design GVU incorporates a continuously vented, gas-tight enclosure and double-wall piping, which allows it to be installed within engine rooms without rendering them a gas hazardous zone. The GVU-ED™ is sized according to engine bore size and cylinder configuration.
GVU-OD™ (Open Design): The open design GVU is a simpler and more cost efficient version without enclosure or double-wall piping. However, for installation on board vessels, a ventilated space (gas valve room) outside the engine room is required. The GVU-OD™ is sized according to engine bore size and cylinder configuration.
Main functions of the GVU
Gas pressure regulation
o Gas pressure is regulated depending on engine load
o The signal for the gas pressure demand originates from Engine Control System
Leak test sequence
o The sequence is performed before engine transfers to gas operation
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
18 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
o It confirms that the GVU valves are working properly and that no internal leakages are detected
Purging with inert gas and venting
o Purging and venting sequences are included in GVU automation
o Safety is ensured during normal operation and in the event of system disturbance
Gas temperature monitoring
o Temperature of fuel gas supplied by FGSS is monitored at GVU inlet. An alarm and gas trip is triggered, if the conditions of the natural gas are outside the operational conditions.
Figure 2-7: GVU Human Machine Interface (HMI)
The complete GVU functionality is controlled by the built-on (GVU-ED™) or remote (GVU-OD™) control system. The control system is based on the Wärtsilä UNIC hardware, and the same reliable components as used on the WinGD Dual Fuel (DF) engines themselves. Based on the signals from the control system logic, the solenoids control the pneumatically actuated valves inside the enclosure. Furthermore, a full-colour HMI panel (Figure 2-7) is mounted on the control cabinet, from where the following parameters can be monitored:
Current status of the GVU
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
19 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
The GVU is Factory Acceptance Tested with the control system before delivery from the factory, thereby safeguarding a high quality and trouble free commissioning.
Components overview
Figure 2-8: GVU-ED™
Figure 2-9: GVU-OD™
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
20 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
The GVU-ED™ is distinguished by an incorporated gas-tight enclosure around the process components (Figure 2-8). Because of the enclosure design, the same principles can be applied as for double-wall piping. The enclosure forms a gas-tight, second barrier against any unforeseen gas leakages. Hence, the GVU-ED™ as such is part of the larger ventilated double-wall piping system. The piping and components are coated on the outside in accordance with marine specific colour schemes. Since the gas related equipment is contained within the unit, the Wärtsilä GVU-ED™ can be installed next to the engine, in a similar fashion as other auxiliary equipment (Figure 3-1). In order to ensure sufficient response of the gas pressure regulation, the length of the pipe between GVU and engine shall not be more than 30 m.
The air vent of the GVU-ED™ enclosure connects to a blower inducing forced air ventilation. The blower is sized to exchange the volume of the enclosure and the annular space of the connected double-wall piping at a rate of minimum 30 times per hour. The blower must maintain a constant under-pressure in the GVU enclosure, thus the enclosure vacuum is constantly monitored. In case of a blower failure the engine trips to diesel mode and the gas pressure in the gas pipe between GVU and engine is released. In the event of over-pressure detection this gas pipe is in addition purged with inert gas (see section 3.5.2). The outlet of the air vent must be discharging to a well ventilated area outside the engine room.
The ventilation of the GVU-ED™ shall be independent of all other ventilation systems.
The annular space of the double-wall piping and the GVU enclosure are constantly monitored by gas detectors (Figure 3-1) for any concentration of gas. In the event of gas detection above a certain concentration, a gas trip (to diesel mode) is triggered by the safety system, and the engine gas piping is vented and purged with inert gas (see section 3.5.2).
GVU-OD™
If a single-wall gas pipe passes through a room below deck, the complete room will become a gas hazardous area. To fulfil safety requirements in an installation utilising the GVU-OD™, a room must be built exclusively for the GVU (Figure 2-10), which must be completely separated from other rooms. This room must be a gas-tight enclosure and must meet the following requirements:
1. All electrical equipment within must fulfil the requirements for hazardous areas, Zone 1.
2. An air lock must be installed at the entrance to the GVU room, with two approved and self-closing doors. The air lock must be large enough for a person to pass through, with only one door open at the same time.
3. Large, redundant ventilation fans for the GVU room are required.
4. The ventilation of the GVU-OD™ shall be independent of all other ventilation systems.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
21 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
5. The ventilation fan must ensure sufficient under-pressure for the GVU room, an air exchange rate of minimum 30 times per hour of piping system and GVU room volume. The fuel gas piping from the GVU room must be double-walled.
6. The maximum pressure in case of gas pipe rupture must be calculated.
The GVU control panel must be installed in a different room than the GVU-OD™, as it does not fulfil requirements for hazardous areas, Zone 1.
Figure 2-10: GVU-OD™ Installation
2.2.3.4 Gas pipe purging
Purging is the process of removing natural gas from the gas piping by substituting it with an inert gas, e.g. nitrogen. The GVU purging sequences ensure that even after detection of a gas leakage, no natural gas can leak to the engine room, thus eliminating potential risks.
In the event of gas detection within the annular space of the double-wall gas piping or the GVU enclosure (GVU-ED™), a gas trip is initiated by the safety system. As an additional safety measure, the gas piping downstream of the GVU and on the engine, is automatically vented and purged with inert gas. For this purpose, the GVU is equipped with a purging valve (‘N2 Engine’ in Figure 2-11), which introduces inert gas under pressure into the fuel gas piping. The inert gas flows through the already open vent valves on the engine, replacing any remaining natural gas in the system. This timed sequence is calibrated during commissioning to exchange the fuel gas piping volume at least 3 times.
Before maintenance work is commenced on the engine and/or the GVU, it is required to purge the related piping. This ensures no natural gas leaks into the engine room. This is a manual process, initiated by operators as needed. For the piping on engine side, the sequence is the same as the one described above. For
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
22 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
the purposes of GVU purging, an additional purging valve (‘N2 GVU’ in Figure 2-11) is located before the GVU to introduce the pressurised inert gas in the system. Vent valves, an integral part of the GVU valve block, allow inert gas to vent, eventually replacing any remaining natural gas in the GVU.
Figure 2-11: GVU purging and venting sequence
2.2.4 iGPR and external fuel gas supply system
The fuel gas pressure can be controlled either by an external gas valve unit or integrated gas pressure regulation. This chapter describes the execution with integrated Gas Pressure Regulation (iGPR).
2.2.4.1 General description of external fuel gas supply system
The external fuel gas supply system upstream of the iGPR consists of gas supply piping and pressurised gas supply. Only some general notes about the gas supply piping and the master fuel gas valve are given in this document.
Gas supply piping
If gas supply piping between gas storage area and engine room is led through other enclosed spaces, the piping must be double-walled or enclosed in a ventilated duct. The duct will be equipped with gas detection and ventilation flow/under pressure detection.
Control of gas supply
The fuel gas supply is controlled by double block and bleed valves, which are activated by the ESS and ECS. The shut-off valves are of normally closed type (de-energized closed) and the bleed valve is normally open (de-energized open).
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
23 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
2.2.4.2 General description of integrated Gas Pressure Regulation (iGPR)
Introduction
WinGD 2-stroke Dual Fuel engines require precise regulation of fuel gas pressure with a timely response to changing load conditions. For this purpose, WinGD has developed the integrated Gas Pressure Regulation (iGPR), which encompasses all performance and safety requirements associated with 2-stroke DF engine applications. In difference to the GVU the components of the iGPR are mounted on the engine.
Main functions of iGPR
Gas pressure regulation
o Gas pressure is regulated depending on engine load
o The signal for the gas pressure demand originates from Engine Control System
Leak test sequence
o The sequence is performed before engine transfers to gas operation
o Confirms the iGPR valves are working properly and no leakages are detected
Purging with inert gas and venting
o Purging and venting sequences are included in iGPR control
o Safety is ensured both during normal operation and in the event of system disturbance
Fuel gas temperature monitoring
o Temperature of fuel gas supplied by FGSS is monitored at iGPR inlet. An alarm and gas trip is triggered, if the conditions of the natural gas are outside the operational conditions.
The complete iGPR functionality is allocated in the iGPR control box E53. The control system is based on the Wärtsilä UNIC hardware, and the same reliable components as used on the WinGD Dual Fuel (DF) engines themselves.
Based on the signals from the control system logic, the solenoids control the pneumatically actuated valves. Furthermore, a full-colour HMI panel is mounted on the control cabinet, from where the following parameters can be monitored:
Current status of gas pressure control
Valve positions and readings from the sensors
Alarm history
Possible active alarms
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
24 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
The iGPR is distinguished by mounting on the engine. Hence the same installation principles are applied e.g. double walled piping and colour scheme.
The air vent of the double walled piping connects to a blower inducing forced air ventilation system.
The blower is sized to exchange the volume of the enclosure and the annular space of the connected double-wall piping at a rate of minimum 30 times per hour. The blower must maintain a constant under-pressure in the double walled piping. The enclosed vacuum is constantly monitored. In case of a blower failure the engine trips to diesel mode and the gas pressure in the gas pipe between master shut-off valve and engine is released.
The outlet of the air vent must be discharging to a well ventilated area outside the engine room. The ventilation of the double walled piping shall be independent of all other ventilation systems.
The annular space of the double-wall piping is constantly monitored by gas detectors (Figure 2-12) for any concentration of gas. In the event of gas detection (i.e. the LEL limit of classes is exceeded), a gas trip (to diesel mode) is triggered by the safety system, and the engine gas piping is vented and purged with inert gas (see chapter 3.5.2).
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
25 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Purging is the process of removing natural gas from the gas piping by substituting it with an inert gas, e.g. nitrogen. The purging sequences ensure that even after detection of a leakage, no natural gas can leak to the engine room, thus eliminating potential risks.
In the event of fire detection or gas detection within the annular space of the double-wall gas piping a gas trip is initiated by the safety system. As an additional safety measure, the gas piping downstream of the iGPR and on the engine, is automatically vented and purged with inert gas. For this purpose, the N2 shut-off valve, as shown in Figure 2-13, introduces inert gas under pressure into the fuel gas piping. The inert gas flows through the already open vent valves on the engine, replacing any remaining natural gas in the system. This timed sequence is calibrated during commissioning to exchange the fuel gas piping volume at least 3 times.
Before maintenance work is commenced on the engine and/or the iGPR, it is required to purge the related piping, ensuring no natural gas leaks into the engine room. This is a manual process only and is initiated by operators as required. The N2 shut-off valve, as shown in Figure 2-14, introduces inert gas under pressure into the fuel gas system piping. The inert gas flows through the open vent valve located upstream of the engine, replacing any remaining natural gas in the system. For the piping on engine side, the sequence is the same as the one described above and shown in Figure 2-13.
Figure 2-13: Inerting of engine gas rail
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
26 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
The main components of the pilot fuel oil systems are pump unit, common rail pipe, supply pipes and injection valves (see Figure 2-15).
The pump unit raises the pilot diesel oil pressure to the required level. It consists of an electrically driven radial piston pump (with built-in overpressure bypass valve), fuel filters and a flow control valve. The pump unit is located on the engine.
Pressurised pilot fuel is delivered from the pump unit into a common rail pipe. The whole high-pressure piping from pump to injectors is of double-wall type. Any leakage is collected from the annular space of the double-wall pipe and led to a collector with a leakage sensor. The common rail piping delivers pilot fuel to each injection valve and acts as a pressure accumulator against pressure pulses.
The DF-engine uses pilot injectors with built-in solenoid valves. The injectors are electronically controlled by the UNIC system allowing exact timing and duration of the injection process. To have the best ignition and combustion stability, the pilot injection valves are combined with pre-chambers. These pre-chambers are directly water-cooled by the HT cooling water from the cylinder cover. Furthermore, the injectors are cooled by system oil.
The pilot fuel injection is also activated during diesel operation to prevent excessive deposit formation on the injector tips and in the pre-chambers. The injected fuel amount is however minimized.
During transfer mode and gas operating mode, the pilot fuel system is constantly monitored to ensure the gas in the cylinder is ignited in a reliable manner. The monitoring includes the pilot fuel pressure level with two redundant measurement signals as well as the electrical circuit needed for activation of the pilot injectors. Furthermore, the installation of two pilot injectors per cylinder further increases
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
27 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
the availability of a reliable ignition source. If the pilot fuel pressure is found to be too low or the electrical wiring has an open loop or short-circuit, the engine control system does not allow the transfer to gas or fuel sharing mode.
An additional safety measure during transfer and gas operating mode is the detection of misfiring, using a redundant detection system. If excessive misfiring is detected, the engine will trip to diesel mode and restore to a safe mode of operation (see Figure 5-1).
Figure 2-15: Pilot fuel high-pressure
2.4 Exhaust system
2.4.1 Exhaust system description
The exhaust gases after a DF-engine may, due to malfunction, contain some unburned fuel gas. The design of the exhaust system must be such that fuel gas cannot accumulate anywhere in the system. Measures are to be taken to prevent damage to equipment and personnel in close vicinity in case of an exhaust gas explosion.
2.4.1.1 External exhaust system after turbocharger (exhaust gas duct):
The exhaust system inside the DF-engine room consists of a compensator and of piping downstream from the turbocharger.
In the exhaust system design the following main features must be considered:
According to class requirements piping and components shall be designed in such a way that gas cannot accumulate in the exhaust system for the installed silencer and exhaust gas boiler.
The exhaust system shall be designed to safely tolerate explosion. This is achieved using explosion relief devices that enable safe discharge of explosion pressure build-up. The amount and placement of these devices should be justified. This is usually performed with a computer simulation.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
28 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Any assumptions of the scenario simulation are to be justified. For example, for a single main engine the relief devices shall be made of self-closing type.
These explosion relief devices should be located so that the hot combustion gases erupting from them will not cause any danger to personnel.
Any bellows to be used in the exhaust system are to be approved by Classification Society.
The exhaust duct of a DF engine must not be connected to the exhaust duct of any other equipment.
Figure 2-16: External exhaust system
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
29 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
2.4.1.2 Exhaust system before turbocharger (exhaust gas manifold):
The exhaust manifold on engine consists of pipe sections connected with flexible bellows. These stainless-steel bellows are critical components with respect to internal overpressure in the exhaust system before the turbocharger. Both, the exhaust manifold and the flexible bellows are designed to withstand a possible explosion without bursting.
2.4.1.3 Safety measures for preventing explosion in exhaust system:
In addition to the safe exhaust gas system design described above, preventive measures on engine side are taken: During engine operation, explosive exhaust gasses could be created by misfiring. Therefore, the engine combustion process is continuously controlled and adjusted. In case excessive misfiring is detected, the engine directly trips to diesel operation mode.
An emergency engine stop, a non-cancellable shutdown or blackout (power-off of Engine Control System) during operation in gas or fuel sharing mode could lead to unburned gas in the engine and the exhaust gas system. Therefore, engine ventilation and exhaust system ventilation is automatically requested before engine restart and a prolonged starting on air is applied.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
30 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
2.4.1.5 Exhaust system with optional Selective Catalytic Reduction (SCR) installation:
Despite the fact that X-DF engines are fully IMO Tier III compliant in gas mode, an SCR system can optionally be installed for achieving IMO Tier III compliance
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
31 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
while operating in diesel mode. The SCR system can be installed in either a Low Pressure (LP) or High Pressure (HP) arrangement. Both systems are integrated with the exhaust system as follows:
The LP SCR system is arranged with the SCR reactor placed after the turbocharger in the exhaust channel. Butterfly valves are installed to isolate the reactor when the SCR system is bypassed. Refer to Figure 2-19 for an indicative layout.
Figure 2-19: LP SCR system with temperature controlled arrangement
The HP SCR system is arranged with the SCR reactor placed between the exhaust receiver and the turbocharger. Two shut off valves are installed at the inlet and outlet of the SCR reactor with a further bypass valve installed to isolate and assist with bypassing the SCR system. Refer to Figure 2-20 for an indicative layout.
Further to the above, the SCR systems also include the UREA dosing and compressed air auxiliary equipment.
The exhaust system with SCR installation must meet the requirements for overpressure and withstand a potential explosion. As such, the components and piping of the SCR system must be designed and comply with the same principles as stated for non-SCR installations above. Furthermore, the installed shut off valves are designed to withstand the potential pressures in case of an exhaust gas explosion.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
32 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
It is to be noted that the SCR can only be used in diesel mode. Whenever gas is used as a fuel (in gas mode or fuel sharing mode), the SCR reactor must be by-passed.
2.4.2 Scavenge air system control
To ensure optimal performance of the engine, it is essential to have a correct air-fuel ratio during the varying operating conditions. WinGD Dual Fuel engines use a proportional exhaust gas waste gate valve to adjust the air-fuel ratio. The exhaust gas waste gate valve allows part of the exhaust gases to bypass the turbocharger’s turbine and can therefore be used to adjust the scavenge air pressure. By changing the scavenge air pressure, the air-fuel ratio is adjusted to the correct value regardless of the varying site conditions (ambient temperature, humidity, etc.).
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
33 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Figure 2-21: Exhaust gas waste gate (EWG) installation
2.5 Dual Fuel Engine Control System
The DF-Engine Control System (ECS) is described in detail in the UNIC-Flex system description. A simplified layout of the control system is shown in the illustration below (Figure 2-22).
Figure 2-22: Simplified control system layout with either GVU or iGPR installation
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
34 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Communication to external systems is described in DENIS. The DENIS-UNIC signal list describes, which signals, connected to the engine safety system, cause a gas trip and/or an engine shutdown.
2.5.2 Dual Fuel engine operating modes
Dual Fuel engines can be operated in the following operating modes:
Diesel mode
Gas mode
Fuel sharing mode (optional)
Note: Transfer mode is used only for transitions between these modes.
In diesel mode, the dual fuel engine operates the same as a conventional diesel engine. The pilot fuel injection remains active with minimised injection amount (LFO).
In gas mode, the dual fuel engine operates as described in chapter 2.1.
The fuel sharing mode is an optional feature that allows increased fuel flexibility. In this mode, the dual fuel engine operates on a variable share of liquid fuel and gas, which is simultaneously combusted in the cylinders. Gas is admitted by the gas admission valves as per normal gas operation. However, an additional portion of liquid fuel is injected through the main fuel injection system. Fuel sharing mode is available above 50% engine load and with a liquid-to-gas ratio of up to 50%. The ratio of liquid-to-gas fuel is requested by the remote control system. The total amount of both fuels is controlled by the speed governor, following the same principles as during a gradual transfer from diesel to gas mode.
Since fuel sharing operation involves gas as a fuel, the same general safety principles apply as when running in gas mode.
Engine start and reversing are always performed in diesel mode.
Manual transfers between the operating modes and automatic gas trips to diesel mode are descripted in chapter 2.5.3 and illustrated in Figure 2-25.
If a Selective Catalytic Reduction (SCR) system is installed, it can only be operated in diesel mode. During gas and or fuel sharing mode the SCR system is by-passed. Consequently, Tier III diesel mode will not be active when gas mode or fuel sharing mode is in operation.
2.5.3 Dual Fuel engine fuel mode transfers and trips
The change of operating mode can be initiated manually by the operator. In direction to diesel mode, the changeover can be initiated automatically by the DF-Engine Control System, or automatically by request from an external system (e.g. safety system). The operating mode can be changed while the engine is running.
Changes of operating modes initiated by the operator are called ‘transfers’. Transfer to diesel mode is an instant change of operating mode initiated by the engine operator at any engine load. Transfer from diesel mode to gas or fuel sharing mode is a gradual change of fuel operation modes, manually initiated by the engine operator and started only after a successful gas leak test.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
37 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Transfer to gas mode is interlocked when the engine is running on HFO. Prior to changing to gas mode from HFO, the engine has to be operated with LFO for a minimum required period to prevent clogging of HFO at the main fuel oil system. The fuel transfer from HFO to LFO, and vice versa, can be done at any time without interruption of engine operation. The fuel oil transfers (LFO <-> HFO) are managed by external systems as on regular diesel engines.
The fuel transfers principles are illustrated in Figure 2-25.
‘Gas trip’ is an automatic change from gas or fuel sharing mode to diesel mode initiated by an unacceptable operating condition, a detected failure or a command received from an external system. It is performed by the Engine Control System. Failures causing gas trip are described in chapter 5.
Note:
Before the operator can request a transfer back to gas or fuel sharing mode, the reason for gas trip must be investigated, the problem resolved and alarm reset
Any failure and condition (see annex in section 5.4) which would initiate a gas trip interlocks the transfer from diesel mode to gas and fuel sharing mode
Transfer to the optional fuel sharing mode is possible when no gas interlock is active and the engine is running above 50% load. When the engine load is reduced below the mode's operating range, an alarm message is released. If the engine power is not increased above 50% within a defined time period, a gas trip is released unless manual transfer is performed in time.
Figure 2-25: Overview of fuel transfers
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
38 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
The Engine Control System has several internal states which are called internal modes:
Start mode
Run mode
Stop mode
Slowdown mode
Emergency stop mode
Shutdown mode
The present document is focusing on describing DF-engine internal modes when engine is running with fuel gas. Some information about internal modes in diesel mode is also shown where considered necessary to understand the gas safety features, for example in a transfer or blackout situation.
2.5.4.1 Engine starting:
Engine can only be started in diesel mode. To perform an engine start, no start block shall be active. Engine start can only be attempted when engine is stopped and ready for start.
Prolonged starting sequence, where the engine is turned minimum 1 revolution by air, is applied after regular stop in gas mode and after ventilation request. This is to ensure that all cylinders are gas free before the fuel injection is activated.
2.5.4.2 Engine running:
Engine running in diesel mode is entered after start mode. Engine is running when speed is above a preset speed limit and no stop, shutdown or emergency stop is active. Gas run mode is activated if transfer from diesel to gas mode is successfully performed.
Engine run mode can be interrupted by the following internal modes:
Stop mode
Slowdown mode
Shutdown mode
Emergency stop mode
Gas run mode can be interrupted in case of gas trip
2.5.4.3 Engine stop from gas operation:
In case of a normal stop request in gas mode, i.e. the engine speed is above minimum speed for gas operation, the Engine Control System changes its internal mode into stop mode. Immediately after the engine stop signal is activated in gas mode, gas shut-off and venting is performed (gas is depressurised and ventilated). The gas admission is de-activated. Pilot fuel injectors are operating longer than the gas admission valves to ensure that all gas in the cylinder liners is burned. Stop sequence is presented in the following graph.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
39 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Shutdown mode is initiated automatically as response to measurement signals. In case of cancellable shutdown, the operating mode will be changed to diesel mode and the engine will continue running as long as the SHD signal does not become active (operator can cancel SHD and continue running in diesel mode). Exhaust ventilation is not required in this situation.
Figure 2-27: Cancellable shutdown sequence of DF-engine from gas mode
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
41 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
If non-cancellable shutdown occurs from gas or fuel sharing mode (i.e. engine overspeed or critical failure), exhaust ventilation is required. Defined shutdown failure states are given in the Marine Installation Manual (MIM). Shutdown mode must be reset by operator and root cause for shutdown must be investigated and corrected before re-start.
Figure 2-28: Non-cancellable shutdown and emergency stop sequence of DF-engine from gas mode
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
42 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Emergency stop mode is activated manually by pressing the emergency stop push-button. Emergency stop is the fastest way to manually shut down the engine. To return to normal operation the push-button must be pulled out and alarms acknowledged.
The emergency stop sequence is identical to the non-cancellable shutdown sequence and shown in Figure 2-28.
2.5.4.6 Transfer from diesel to gas mode:
Figure 2-29: Transfer from diesel to gas mode
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
43 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Engine room design, arrangement and location as well as equipment and systems installed will vary depending on specific ship installation, but the main principles concerning gas safety and redundancy must follow the minimum requirements stated in this chapter.
3.2 Engine room arrangement
With double-wall gas pipe configuration, the engine room is considered a gas safe area according to IGC Code 1.3.17.10, 1.3.18 and IGF.
Permanent gas detectors are installed in the engine room.
There are no special requirements as to the location of auxiliary systems in the room. The automatic fuel gas shut-off valve must be installed outside the engine room.
External gas piping to the engine room led through enclosed spaces is to be equipped with ventilation and gas detection as per IMO regulation.
3.3 Safety of electrical equipment in engine room
Engine rooms of DF-engines on seagoing vessels are considered gas safe according to IGC and IGF codes. Therefore, electrical equipment inside the engine room does not need to be certified Ex apparatus. Sensors in hazard zone see chapter 3.7.1.
3.4 Ventilation of engine room
Engine room ventilation must be forced (IGC code 16.2.1 and IGF code). This means, no difference in comparison to normal engine room ventilation via engine room ventilation fans. The engine may suck combustion air directly from outside with a dedicated duct (option). Ventilation should be particularly effective in the vicinity of electrical equipment and prevent the formation of ‘dead spaces’ in accordance with IGC Code regulations.
3.5 Breathing / venting arrangement of certain DF-engine systems
3.5.1 General description
From areas described in the following, small volumes of gas might require venting from the engine room to the outside atmosphere, away from any sources of ignition.
Notice that a gas hazardous zone is created around the location of vent outlet. These outlets can be located in the funnel, provided that the distance to any source of ignition, such as exhaust gas outlet (engines, oil-fired boiler, incinerator, gas combustion unit, inert gas generator, etc.), is at least as big as required by the rules of the classification society in charge of the installation.
Vent outlets and vent pipe discharges that may contain fuel gas are to be located away from vent inlets. Alternatively, to venting outside into atmosphere, other means of disposal (e.g. a suitable incinerator) can also be considered. However, such kind of arrangement must be accepted by Classification Society case-specifically.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
45 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
All breathing and ventilation pipes that may contain fuel gas must be built continuously sloping upwards, so that there is no possibility of fuel gas accumulating inside the piping.
These pipes have an open end at atmospheric pressure. Under all normal operation conditions there is no pressured fuel gas concentration in these pipes. Consequently, the probability for any leakage of natural gas from these pipes is very low, especially in any significant concentration of pressured gas, and therefore these pipes can be made in single-wall execution.
3.5.2 Gas piping venting
At the end of gas operation, when the engine stops or changes to diesel mode, the gas piping on the engine is depressurised. If the gas pressure on engine is too high during transient operation, the vent valves are opened for very short periods to reduce the gas pressure. Before transfer from diesel to gas or fuel sharing mode the engine gas supply pipes are filled with natural gas (flushing).
At the end of gas operation or if the gas pressure is too high during transient operation, the fuel gas, inert gas or mixtures of both is conducted from the gas supply manifold on the engine through the gas piping vent to a suitable place outside the engine room. The driving end and free end vent lines of one engine may be combined to one common pipe, provided that the common pipe diameter is increased accordingly. However, vent lines from the gas supply manifold of different engines must not be interconnected to a common outlet.
The ends of ventilation pipes must be equipped with flame arresters.
3.5.3 Venting of gas supply piping annular space
3.5.3.1 If GVU is installed:
Layout:
For the annular space ventilation layout, please refer to section 2.2.3.
Actions upon ventilation failure of double-wall gas supply piping:
The negative ventilation air pressure in the annular space is monitored by the GVU-ED™. A possible loss of negative pressure (∆p) causes a gas shutdown to the GVU enclosure, and the GVU itself shall automatically initiate the engine to trip to diesel.
3.5.3.2 If iGPR is installed:
Layout:
For the annular space ventilation layout, please refer to section 2.2.4.
Actions upon ventilation failure of double-wall gas supply piping:
The negative ventilation air pressure in the annular space is monitored by the ESS (pressure switches) and ECS (analogue pressure sensor). A possible loss of negative pressure (∆p) initiates automatically a trip to diesel.
3.5.4 Cooling water system ventilation
The 2-stroke crosshead engine has a high-temperature (HT) and a low-temperature (LT) cooling water system. In case of component failure (crack in liner, exhaust valve cage or pilot fuel pre-chamber) the HT cooling water system might be contaminated with gas. This gas could end up in the cooling water
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
46 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
expansion tank. Therefore, the cooling water expansion tank must be a closed-up type.
Ventilation of the HT expansion tank is effected by a vent pipe which leads to a safe place outside the engine room. This prevents any gas release into the engine room or funnel. Some Classification Societies may additionally require a HC sensor in the HT expansion tank. For the LT cooling water system, it is not required, because the water will not have direct contact with the gas.
If a combined cooling water system (HT and LT system together) is installed, the expansion tank must have the same arrangement as the HT expansion tank.
Any instrumentation installed in the cooling water expansion tank must be certified Ex apparatus.
3.6 Gas detection in DF-engine room, gas supply system and engine
3.6.1 If GVU is installed:
Gas detectors must be installed at the following locations:
In GVU venting blower air outlet line, for detecting any leakage of the gas pipes and gas equipment in the double-wall installation and GVU respectively (Ship yard scope)
On the engine for piston underside gas detection (Engine supplier)
According to IGF and IGC codes the following sensors are required:
In case that a GVU-ED™ is installed, the engine room requires a minimum of two separate hydrocarbon (HC) gas detectors (see Figure 3-1):
o One gas detector above engine
o One gas detector above GVU
If a GVU-OD™ is installed, minimum one hydrocarbon (HC) gas detector must be installed in the engine room.
Deviations from the above execution may be agreed with classification societies in individual cases.
All gas detector signals are connected to the external Gas Detection Systems, except the gas detector for piston underside gas detection which is directly connected to the Engine Control System. Depending on ship’s arrangement and requirements of IMO and Classification Society, the alarm centrals can be in one or more of the following locations:
Bridge
cargo control room (LNG carrier)
engine control room
The gas detectors are to be approved by Classification Society.
When gas concentration is detected to rise above Class specified limit, an audible and a visible alarm is initiated in the rooms specified by the Classification Society. The Gas Detection System shall be tested and calibrated according to the maintenance schedule and procedure as advised by the manufacturer or Classification Society.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
47 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Figure 3-1: Example of gas detector positioning in engine room, gas supply system and engine with GVU
The piston underside gas detection is ensured by a gas detector which is installed in the piston underside air sampling line. The gas detector is directly connected to the Engine Control System. The whole piston underside gas detection arrangement including the gas detector is delivered by the engine maker.
Amount and position of other gas detection sensors will be defined by the shipyard according to Classification Society rules, IGF Code and IGC Code.
If gas is detected by the external Gas Detection System, the engine will trip to diesel and the pipes between GVU and engine will be purged with inert gas. Further measures on the vessel are taken as defined by Shipyard and Classification Societies.
If gas is detected in the piston underside area, the engine will trip to diesel.
3.6.2 If iGPR is installed:
Gas detectors must be installed at following locations:
In venting blower air outlet line, for detecting any leakage of the gas pipes and gas equipment in the double-wall installation (Ship yard scope)
On the engine for piston underside gas detection (Engine supplier)
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
48 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
The IGF and IGC codes require as a minimum two separate hydrocarbon (HC) gas detectors sensors:
One gas detector above engine
One gas detector above iGPR
Deviations from above execution may be agreed with classification societies in individual cases.
All gas detector signals are connected to the external Gas Detection Systems, except the gas detector for piston underside gas detection which is directly connected to the Engine Control System. Depending on ship’s arrangement and requirements of IMO and Classification Society, the alarm centrals can be in one or more of the following locations:
Bridge
cargo control room (LNG carrier)
engine control room.
The gas detectors are to be approved by Classification Society.
When gas concentration is detected to rise above Class specified limit, an audible and a visible alarm is initiated in the rooms specified by the Classification Society. The Gas Detection System shall be tested and calibrated according to the maintenance schedule and procedure as advised by the manufacturer or Classification Society.
The piston underside gas detection is ensured by a gas detector which is installed in the piston underside air sampling line. The gas detector is directly connected to the Engine Control System. The whole piston underside gas detection arrangement including the gas detector is delivered by the engine maker.
Amount and position of other gas detection sensors will be defined by the shipyard according to Classification Society rules, IGF Code and IGC Code (see Figure 2-12).
If gas is detected by the external Gas Detection System, the engine will trip to diesel and the pipes between iGPR and engine will be purged with inert gas. Further measures on the vessel are taken as defined by Shipyard and Classification Societies.
If gas is detected in the piston underside area, the engine will trip to diesel.
3.7 Definition of hazardous zones
Protection and certification requirements for components used in explosion hazardous areas are defined based on explosion hazardous zones in which they are used. Definitions of hazardous zones according to IEC 60092-502:1999 (used as reference in IGC and IGF Codes) are:
Zone 0: Area in which an explosive gas atmosphere is present continuously or is present for long periods
Zone 1: Area in which an explosive gas atmosphere is likely to occur in normal operation
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
49 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Zone 2: Area in which an explosive gas atmosphere is not likely to occur in normal operation and, if it does occur, is likely to do so only infrequently and will exist for a short period only
The engine room and engine crank case are considered as gas safe non-hazardous areas and do therefore not refer to above hazardous zone definitions.
The following figures (Figure 3-2, Figure 3-3, Figure 3-4 and Figure 3-5) show explosion hazardous areas:
Figure 3-2: Cylinder unit and piston underside (hazardous zones)
Figure 3-3: Fuel gas system (hazardous zones)
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
50 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
On the Dual Fuel engine that is fed by an external GVU, only the gas pipe pressure sensors PT3595C and PT3597C are installed in a way, that they measure in hazard zone 0 and that the electrical part is in zone 1. The intrinsically safe sensors are connected via Zener barrier to UNIC.
3.7.1.2 Dual Fuel engine with iGPR installation
These intrinsically safe sensors and switches of DF engine and iGPR measure in hazard zone 0 and the electrical part is in zone 1:
FI3942C Gas Flow iGPR
PS3901S Gas Inlet Pressure Low
PS3902S Gas Inlet Pressure High
PT3941C Gas Pressure before iGPR
PT3595C Gas Pressure Fuel Side
PT3597C Gas Pressure Exhaust Side
PT3901C Gas Inlet Pressure
PT3906C iGPR Gas Pressure between shut-off valves
TS3901S Gas Inlet Temperature High
TS3902S Gas Inlet Temperature Low
TT3901C Gas Inlet Temperature
3.8 Actions upon fire in engine room
Fire alarm in the engine room shall initiate an automatic trip to diesel and shut off the master fuel gas valves.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
52 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
For certain applications, the twin engine propulsion may be applied. It is to be ensured that specific requirements and rules of the classification societies in charge are taken into consideration. Especially, but not limited, to the following:
4.1 Shaft locking device
On twin engine operated vessels, a shaft locking device must be installed on each propeller shaft. This allows individual shaft lines to be locked during maintenance and engine shut downs. This device protects the stopped engine against turning by the wind milling effect during sailing. Engine start interlock and turning gear interlock is applied, when the shaft is locked by the shaft locking device.
4.2 Exhaust gas system protection
If there is more than one gas engine installed, each engine must have its own exhaust gas installation to avoid mixing of the exhaust gases. Also, each system must be equipped with protection pressure relief device to protect the system against overpressure after explosion. The device should be chosen according to classification rules (spring loaded or rupture discs).
4.3 Auxiliary Systems
The auxiliary systems of each engine shall be independent of each other. For LT cooling water and cylinder lubricating oil supply a certain combination according to the following descriptions is possible:
4.3.1 LT cooling water system:
Common cooling water system possible; LT cooling water supply to both engines arranged in parallel
One independent stream per engine to LO cooler and high-temperature cooling water cooler
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
53 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
This chapter is summarising causes and effects of safety measures with focus on natural gas as fuel.
5.1 Key safety measures:
The availability of the DF engine is based on the ability to change to diesel mode while running on gas.
An active gas trip will block transfer from diesel mode to gas and fuel sharing mode
A shutdown or emergency stop will cause an engine starting interlock in the Engine Control System
If the engine has been stopped while using fuel gas with emergency shutdown or non-cancellable shutdown, i.e. before re-starting the engine in diesel mode, it is necessary to perform the exhaust ventilation sequence by the use of the auxiliary blowers. The auxiliary blowers must be designed as non-sparking type according to Classification Society rules, IGF Code and IGC Code
All engine control panels will be equipped with an emergency gas trip button
Engine starts in diesel mode only
Gas and fuel sharing mode can be used only when engine is operating ahead
Reversing of engine can be done in diesel mode only
With an external engine power measurement failure, only diesel operation is available
A Propulsion Control System failure will only allow operation on diesel from the LDU’s
5.2 Combustion control and monitoring functions:
5.2.1 Knock detection:
When knocking is detected on one cylinder, the ECS starts to reduce the amount of gas to the affected cylinder. This will adjust the air-fuel ratio, which prevents knocking. When a sudden heavy knocking is detected by the knock detection system on one or more cylinders, the engine will automatically trip to diesel mode.
When a marked deviation of compression/combustion pressures on a cylinder is detected, the ECS will adjust the exhaust valve timing and the amount of gas admission to that specific cylinder. If there is no response to the gas adjustment within a defined period, the engine is automatically tripped to diesel mode.
5.2.3 Misfiring detection:
When misfiring of one or more cylinders is detected for a defined number of cycles, the engine will automatically trip to diesel mode.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
56 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
5.3 Cause and effect chart for engine malfunctions
The following cause and effect chart of safety measures focuses on engine operation in gas and fuel sharing mode, and on faults affecting gas safety.
Table 5-1: Cause and effect chart in gas and fuel sharing mode
Fault Detection Action
Failure which causes trip to diesel mode without activating the request for engine load reduction
Explained in table 5-8
GT to diesel mode
Failure which initiates engine load reduction - engine SLD in Gas Mode (no gas trip is activated, however, in fuel sharing mode the load reduction indirectly will trigger a gas trip)
Explained in table 5-8
SLD in gas mode
Failure which initiates trip to diesel mode and engine load reduction
Explained in table 5-8
GT/SLD in diesel mode
Failure which leads to engine SHD Explained in table 5-8
GT/SHD
Emergency stop command Explained in table 5-8
GT/SHD
Following failures of gas pressure supply and regulation will cause trip to diesel mode:
Gas pressure too high or too low
Gas pressure build-up time elapsed (during start-up & transfer)
Gas leak detected (see chapter 3.6 for details)
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
57 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Engine or gas pressure regulation compartment ventilation failure or loss of negative pressure
Gas temperature too high or too low
5.4 Extract of alarm list – only the most critical alarms for gas operation included
The below monitoring tables are grouped per system (ESS, AMS, ECS) to which the sensor and actuators are connected. Only important alarms and their related actions of those systems are mentioned, i.e. whose single failure would trigger a gas trip (GT), slowdown (SLD) or shutdown (SHD) by the connected system.
The definition of all alarms and ensuing actions is available in the final engine documentation (Marine Installation Manual (MIM) and Operation Manual (OM)).
Engine safety is described as interactions between the following systems:
Engine Safety System (ESS)
Alarm and Monitoring System (AMS)
Engine Control System (ECS)
Gas Valve Unit (GVU) or Integrated Gas Pressure Regulation (iGPR)
Gas Detection System (GDS)
The following interaction rules are applied:
Execution of gas trip
Gas supply
o ESS stops the fuel gas supply by activation of double block and bleed valve block
o ECS closes the gas admission valves, closes shut off valves and opens vent valves on engine
Pilot fuel supply ECS reduces the pilot fuel amount injected
Mail fuel supply ECS activates the main injectors and main fuel pumps
Execution of engine shutdown
Gas supply
o ESS stops the fuel gas supply by activation of double block and bleed valve block
o ECS closes the gas admission valves, closes shut off valves and opens vent valves on engine
Pilot fuel supply High-pressure pilot fuel pump is stopped by both ESS and ECS
Mail fuel supply
o the ESS depressurises the main fuel rail
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
58 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
Gas Trip, Light Knock Can't Be Eliminated (load limit)
X
Misfiring Misfiring Cyl #N X X X
Misfiring Detection by Press. Sensor Fail Cyl #N
X
Misfiring Detection by TVM Fail X X*
Pilot fuel injection Pilot Fuel Injector 1 Open/Short Circuit Cyl #N
X *1
Pilot Fuel Injector 2 Open/Short Circuit Cyl #N
X *1
Pilot Fuel Injector 1 and 2 Open/Short Circuit Cyl#N
X X
*1 If one pilot fuel injector is out of order at high load, it shows only minor or none effect. At low load possibly gas trip occurs by unstable combustion. In diesel mode a gas interlock is active.
* The misfiring detection by TVM is based on the speed and crank angle measurement system. Only if the speed and crank angle cannot be determined, TVM cannot function.
Substitute for: PC
Q-Code X X X X X
Modif C EAAD085983 24.06.2015 D EAAD086631 11.05.2016 E EAAD087514 24.02.2017 F EAAD088737 30.10.2017
Number Drawn Date Number Drawn Date Number Drawn Date Number Drawn Date
Product
W-2S
Description
2-S Dual Fuel Engine Safety Concept
Made 27.06.2014 S. Arp Main Drw. Page
62 / 63 Material ID
PAAD149646 Chkd 10.11.2017 J. Gärtitz Design Group
