1. CAMLESS ENGINES

2. Introduction
CAMS
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
But they are inflexible except VTEC & VVT-I
Engineers could not vary timing, lift & duration of valve opening infinitely

3. CAMLESS ENGINES
Eliminated mechanical linkages
Could provide infinite variation of valve parameters
It can make engines clean, efficient & responsive

4. Working of conventional engines
The crankshaft turns camshaft which operates valves by mechanism as in figure
Spring brings back valve to initial position
Timing of engine valves depends on shape of cams

5. Conventional engine valves

6. Engineers must design cams in the development stages
This design compromises b/n engine power & fuel efficiency
Considering this compromise automobile companies brought variable valve timing mechanisms
But is effects were limited

7. Camless engines overview
Main sensors -
Engine load sensor Exhaust gas sensor
Valve position sensor Engine speed sensor
ELECTRONIC CONTROL UNIT
SENSORS
ACTUATORS

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

9. Actuators It is a electro-hydraulic camless valve train (ECV)
Uses elastic property of compressed hydraulic fluid which acts like a liquid spring, accelerates & decelerates the valves

10. Hydraulic pendulum
Involves conversion of PE to KE and back to PE with minimum energy loss
During acceleration of valves PE is converted to KE
During deceleration of valve energy of moving valve is returned to fluid

11. Detailed view of Hydraulic Pendulum

12. Operation of hydraulic pendulum

15. Lift, timing & duration of valve opening is varied by controlling solenoid valves
This is done by ECU when signals are sent from the sensors

16. Modifier Rod Used to impart Unequal lift to the paired valves
Zero motion to any valve

17. Modifier Rod Operation

19. Advantages
Offers continuously variable & independent control of all aspects of valve motion - lift, operation duration, event of opening
ECV system can control valve velocity, valve acceleration and deceleration

20. Resultant Advantages Better fuel economy- 7 to 10 % increase
Higher torque & power- 10 to 15 % increase
Lower exhaust emissions- EGR system is eliminated since EGR effect occurs on its own & thus reduces NOx emissions
Reduction in size & weight

21. Disadvantages Opening & closing of valves requires some power-
Electromechanical- alternator
Electrohydraulic- accumulator
Sophisticated electronic control required for gentle seating of valves
Current solenoids cannot run at high rpms;
Hidden cost of microprocessor & software controls

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

23. Thanks