VISVESVARAYA TECHNOLOGICAL UNIVERSITY BELGAUM

C.BYREGOWDA INSTITUTE OF TECHNOLOGY

THORADEVANDAHALLI VILLAGE &POST KOLAR-SRINIVASAPUR ROAD, KOLAR-563101.

TECHNICAL SEMINAR ON

CAMLESS ENGINE PRESENTED BY UNDER THE GUIDANCE OF KIRAN N(1CK11ME021) Mr.CHOWDA REDDY C 8TH SEM,MECHANICAL ASST.PROFESSOR DEPARTMENT OF MECHANICAL ENGINEERING CBIT,KOLAR

Presentation outline Introduction Cams Conventional engine valves Disadvantages Camless engines overview Actuators Electromechanical valve actuator overview Operation of electromechanical poppet valves Electromechanical ball valves Advantages Disadvantages Conclusion References

Introduction

The new emerging technology for automotive technology are the Camless engine which the engine does not have camshaft to lift the both intake and exhaust valve.

CAMS

• Cams are designed for particular valve timings• Control the breathing channels (valves) of an IC engine• Connected to camshaft which is operated by crankshaft• Cams push open valves at proper time & guide their

closure• Cams are placed with different angular positions on cam

shaft in multicylinder engines.

Conventional engine valves

Working Of Conventional Engines

• The crankshaft turns camshaft which operates valves by mechanism

• Spring brings back valve to initial position

• Timing of engine valves depends on shape of cams

Disadvantage

• Due to more mechanical linkages frictional losses are more and power output is less.

• Power required is more• Size of engine is large and it is noisy• Emission of NOx is more in conventional engine

Camless engines overview

• Main sensors - Engine load sensor Exhaust gas sensor Valve position sensor Engine speed sensor

ELECTRONIC CONTROL UNIT

SENSORS ACTUATORS

•Sensors sense parameters & send signals to ECU•ECU contains microprocessors with associated software•This ECU controls the actuators to work according to requirements

Actuators

• It is a electro-mechanical camless valve train (EMV)

Electromechanical valve actuator overview

Solenoids – Camless Valve Actuation1. Current flows through the coil and a magnetic field forms

around the coil2. The magnetic field attracts the armature toward the

center of the coil3. As the armature moves downwards, the spring expands

and the valve opens4. When current stops flowing to the coil, the magnetic field

collapses and the spring expands and shuts the valve

Operation of electromechanical poppet valves

Electromechanical ball valves

• It consists of a ball through there is a passage passes.• If the ball is rotated such that passage lines up with other openings in the valve assembly, gas can pass through it.• The disc is permanently attached and indexed to the ball valve

and contains permanent magnets around its perimeter.• A crank trigger sensor on the crankshaft provides information

about the position of the piston relative to top dead center.

Advantages

• Offers continuously variable &independent control of all aspects of valve motion –lift, operation duration, event of

opening.• ECU system can control valve velocity, valve acceleration and

deceleration.• Reduction in size & weight.• Better fuel economy- 7 to 10 % increase due to by proper and

efficient controlling of the valve lifting and valve timing. • Lower exhaust emissions- EGR system is eliminated since EGR

effect occurs on its own & thus reduces NOx emissions• Increased life of engine

Disadvantages

• High Cost• Increased power consumption• Air gap between the solenoids may demand a

higher magnitude of current during certain periods

• The control strategy for valve seating velocity needs to be modified

Conclusion

Even though some disadvantages are present, we can expect electro hydraulic & electromechanical valves to replace the conventional camshaft technology.

camless engine valve train.mp4

Current status of camless engine

• Camless valve trains using solenoids or magnetic system are being investigated by BMW and FIAT and FEERARI

• They are being prototyped by valeo and Racardo.• Used in new fiat 500

References

• Michael M.Schechter and Michael B.Levin “Camless Engine” SAE paper 960581• P. Kreuter, P. Heuser, and M. Schebitz, "Strategies to Impove SI-Engine

Performance by Means of Variable Intake Lift, Timing and Duration", SAE paper 920449.

• K. Hatano, k. Lida, H. Higashi, and S. Murata, “Development of a New Multi-Mode Variable Valve Timing Engine”,SAE paper930878

• J-C. Lee, C-W. Lee, and J. Nitkiewitz, “The Application of a Lost Motion VVT System to a DOHC SI Engine”,SAE paper 950816

• John B. Heywood, “Internal combustion engine fundamentals”• William H. Crouse. “Automotive mechanics.”• John Steven Brader ,A Thesis on Development of a Piezoelectric

Controlled Hydraulic Actuator for a Camless Engine

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