Diesel Fuel Filter Heater Assembly

Group IXJustin Brewer, Abanoub Riyad, Ethan Smelcer

Benjamin Rogers, Mohanad Al-Mokhadm

ME 4444

Dr. M. Sundaram

Diesel Clouding:

● Temperature at which dissolved wax

comes out of solution -28°C (-18°F) to -

7°C (+20°F)

● Wax Coats Filter Medium Blocking Fuel

Flow (Starves Engine)

● Primary Issue: Cold Start-Ups

Background Information

Background Information

Single Dual

● Korean Forklift Customer:

- Needed additional heater performance

for cold start-ups

● Cummins’ Solution:

- “Dual Sandwich” 24V PTC Heater

Configuration

● Lab Tests Conducted:

- Compared Heater Performance With

Other available Heater Solutions

Background Information

“Dual Sandwich” Heater Configuration

Cummins’ Lab Test Data:

● Outlet Temperature-Fastest Rise-Time

Background Information ● Cummins uses Positive Temperature

Coefficient (PTC’s) stones as heating elements.

Cummins Fuel Heater A typical configuration of PTC stones

Background Information

Resistance versus Temperature for PTC Stones

PTC’s 2 Stages:

● Self Regulating: Voltage passes

through allows the PTC to heat which

decreases the resistance and allows

more current to flow.

● Self Protecting: When temperature

reaches the switch temperature, the

resistance increases exponentially

and no more current passes through.

Need Statement

Leak Path

Project Deliverables:1. Eliminate the additional Leak

Path between the 2 heaters.

2. Decrease the cost of additionally machined parts required for added length.

3. Decrease the moment arm that is created due to dual heaters.

4. Decrease cost of 2 heaters.

Project Constraints● Only one more disc heater will be added.

● Heater testing takes place using diesel fuel with a cloud point of -12 0C.

● Heater testing takes place using a pump flow of at least 4 liters per

minute.

● Heater testing takes place after turning them for 15 seconds before

pump operation.

● Heater testing takes place for 20 minutes.

● Mounting of heater has to match with the currently-used head

● peak Current of 25 Amps MAX

Design ConceptsConcept 1:● 2 PTC Stone arrays in a single circuit in housing

Design ConceptsConcept 2:● 1 PTC Stone array in housing and 1 PTC Stone array on top of

housing set in the head of the filter both on separate circuits

Concept 3:● 2 PTC Stone arrays two separate circuits in housing

Design Concepts

Concept 1:● Single circuit would not produce

enough heat based on circuit analysis.

Concept 2:● Unable to build due lack of access

to different PTC stones.

Concept 3:● Showed good results from initial

analysis.● Access to material for

manufacturing.● Continued on to simulation phase.

Design ConceptsSelection Criteria Baseline Weight Concept

#1Concept

# 2Concept

# 3

Max Power Consumption

0 5 + - +

Easy Assembly 0 5 - - +

Size(thickness) 0 1 S S +

Number of Plugs 0 1 + + -

Number of Thermostat

0 1 + + -

# of Pluses 7 2 11

# of Minuses 5 10 2

Single and Dual Simulation

Single● Inlet Pressure: 0.3448 psi● Out Temperature: -6.84 ºC

Dual● Inlet Pressure: 0.6047 psi● Out Temperature: 3.66 ºC

Simulation Results

Prototype Simulation

● Inlet Pressure: 0.1502 psi● Outlet Temperature: 1.33 ºC

Simulation Results

Heater Inlet Pressure

(psi)

Outlet Pressure

(psi)

Press Diff.

(psi)

Outlet Temperature

(ºC)

Inlet Temperature

(ºC)

Temp Diff

(ºC)

Single 0.3448 0 0.3448 -6.84 -17 10.16

Dual 0.6047 0 0.6047 3.66 -17 20.66

Prototype 0.1502 0 0.1502 1.33 -17 18.33

Overall Results

PrototypeConcept 3:● CFD simulation as well as circuit analysis show good results.● Continued on to the build and testing phase, comparing results

to the single and dual sandwich heaters test results.

● Housing of prototypes were produced by using a 3D Systems ProJet™ SD 3500 printer

● Printer is located at the STEM Center at Tennessee Tech University

Manufacturing Prototypes

Plate Fabrication

● Four plates with different dimensions were needed for the prototype

● 2024 aluminium alloy sheets with 0.5 mm thickness

● Test Rig was needed to validate simulation results

● Temperature and pressure, at the inlet and outlet were measured as well as volumetric flow rate

● Pump was used to circulate fuel through the system.

● Fuel cycled through 12 gallon Diesel tank● Power supply of two 12 Volt batteries in series● Clamp on multimeter used to measure current

draw

Test Configuration

1. Fuel cooled to 0ºC or lower2. Reservoir was connected to assembly and

the system was primed at room temperature

3. Heater was turned on for 15 seconds4. Pump was then turned on5. Multiple group members assisted in

collecting data points6. Each test was ran for 20 minutes

Testing Setup/Constraints

Simulation vs TestingSimulation Test

Measurements were taken DIRECTLY at inlet and outlet of the heaters themselves.

Measurements were taken before and after filter assembly.

Variable viscosity / Density Not Modeled Variable viscosity affects overall performance.

Inlet Flow Rate modeled as CONSTANT Flow rate measured as variable.

Heat Rate of PTC Elements modeled as constant.

Heat Rate of PTC Elements is actually a function of their own internal temperature.

Pressure drop neglects filter Pressure drop includes filter

*Test results CANNOT be compared DIRECTLY to Simulation Results

Test Results (Single Heater)

Test Results (“Dual-Sandwich”)

Test Results (Prototype)

Test Results (Comparison)

Test ∆P (psi) ∆T (ºC) Flow (L/min)

Single 5.629 5.033 4.101

“Dual-Sandwich” 5.138 6.298 6.149

Prototype 5.455 4.364 5.451

Average of last 10 minutes of each test’s results:

Test Results (Prototype)Potential Prototype Issues:

1. Poor circuit connections

2. Thermal conductivity of aluminum used

3. Poor flow around PTC elements

Cost

Accomplishments

● Eliminated the leak path.

● 25% moment arm reduction

● Material Cost reduction

● From CFD simulations, the design concept is valid.

Recommendations

● Different type of PTC stones with different properties.

● Different metal for the plates with different thermal

conductivity.

● Use different thermostat with higher set point for the

bottom circuit.

● Different flow path for diesel.

Acknowledgments

● Cummins Filtration

● University of Tennessee- Center for Industrial Services

● Tennessee Technological University

ME Department

Dr. Meenakshi Sundaram

Chris Mills

Jeff Randolph

Robert Reab

Questions?