Camless Engine

Prepared By:-Prepared By:-

Dharsenda Milan NDharsenda Milan N

IntroductionIntroduction

In the camless valve train the valve motion is In the camless valve train the valve motion is controlled directly By a valve actuator- There is controlled directly By a valve actuator- There is no cam shaft or connecting mechanism.no cam shaft or connecting mechanism.

Precise electrohydraulic camless valve train Precise electrohydraulic camless valve train controls the valve operations opening closing controls the valve operations opening closing etc. etc.

The Seminar looks at the working of the The Seminar looks at the working of the electrohydraulic camless engine its, general electrohydraulic camless engine its, general features and benefits over conventional engines.features and benefits over conventional engines.

Conventional valve train Conventional valve train mechanism mechanism

An overview of camless engineAn overview of camless engine

To eliminate the cam, camshaft and other To eliminate the cam, camshaft and other connected mechanisms, theconnected mechanisms, the

Camless engine makes use of three vital Camless engine makes use of three vital components – the sensors, the electronic control components – the sensors, the electronic control unit and the actuatorunit and the actuator

Sensors Electronic control unite ActuatorsSensors Electronic control unite Actuators

Mainly five sensors are used in connection with the valve Mainly five sensors are used in connection with the valve operation. One for sensing the speed of the engine, one operation. One for sensing the speed of the engine, one for sensing the load on the engine, exhaust gas sensor, for sensing the load on the engine, exhaust gas sensor, valve position sensor and current sensor. The sensors valve position sensor and current sensor. The sensors will send signals to the electronic control unit.will send signals to the electronic control unit.

The electronic control unit consists of a microprocessor, The electronic control unit consists of a microprocessor,

which is provided with a software algorithm. The which is provided with a software algorithm. The microprocessor issues signals to the solid-state circuitry microprocessor issues signals to the solid-state circuitry based on this algorithm, which in turn controls the based on this algorithm, which in turn controls the actuator, to function according to the requirements.actuator, to function according to the requirements.

Hydraulic pendulumHydraulic pendulum

Valve opening and closingValve opening and closing

Unequal lift modifierUnequal lift modifier

In a four-valve engine an actuator set consisting In a four-valve engine an actuator set consisting of two solenoid valves and two check valves of two solenoid valves and two check valves controls the operation of a pair of intake or a pair controls the operation of a pair of intake or a pair of exhaust valves. Solenoids and check valves of exhaust valves. Solenoids and check valves are connected to a common control chamber are connected to a common control chamber serving both valves. In a four-cylinder engine serving both valves. In a four-cylinder engine there are total of eight control chambers there are total of eight control chambers connected to eight pairs of valves. For each pair, connected to eight pairs of valves. For each pair, the volumes below the hydraulic pistons are the volumes below the hydraulic pistons are connected to the high pressure reservoir via a connected to the high pressure reservoir via a device called the lift modifier. device called the lift modifier.

Paired valves with unequal lift Paired valves with unequal lift control control

Design approach for camless Design approach for camless engineengine

The original cylinder head with all the valves, The original cylinder head with all the valves, springs, camshafts, etc. was replaced by a new springs, camshafts, etc. was replaced by a new cylinder head assembly fully integrated with the cylinder head assembly fully integrated with the camless valvetrain. The camshaft drive was camless valvetrain. The camshaft drive was eliminated, and a belt-driven hydraulic pump eliminated, and a belt-driven hydraulic pump was added. There was no need for lubrication, was added. There was no need for lubrication, and the access for engine oil from the engine and the access for engine oil from the engine block to the cylinder head was closed off. No block to the cylinder head was closed off. No other changes to the engine have been made.other changes to the engine have been made.

Cylinder headCylinder head

Components of camless engineComponents of camless engine

Engine valve Engine valve Solenoid valveSolenoid valve Lift modifier Lift modifier High Pressure PumpHigh Pressure Pump Low Pressure PumpLow Pressure Pump Cool-down AccumulatorCool-down Accumulator

AdvantagesAdvantages

Electro hydraulic camless valve train offers a Electro hydraulic camless valve train offers a continuously variable and independent control of all continuously variable and independent control of all aspects of valve motion. This is a significant aspects of valve motion. This is a significant advancement over the conventional mechanical valve advancement over the conventional mechanical valve train. train.

the ECV system is capable of controlling the valve the ECV system is capable of controlling the valve velocity, perform selective valve deactivation, and vary velocity, perform selective valve deactivation, and vary the activation frequency. the activation frequency.

It also offers advantages in packaging. Freedom to It also offers advantages in packaging. Freedom to optimize all parameters of valve motion for each engine optimize all parameters of valve motion for each engine operating condition without compromise is expected to operating condition without compromise is expected to result in better fuel economy, higher torque and power, result in better fuel economy, higher torque and power, improved idle stability, lower exhaust emissions and a improved idle stability, lower exhaust emissions and a number of other benefits and possibilitiesnumber of other benefits and possibilities

ConclusionConclusion

An electro hydraulic camless valve train was developed for a An electro hydraulic camless valve train was developed for a camless engine. Initial development confirmed its functional ability to camless engine. Initial development confirmed its functional ability to control the valve timing, lift, velocity, and event duration, as well as control the valve timing, lift, velocity, and event duration, as well as to perform selectively variable deactivation in a four-valve to perform selectively variable deactivation in a four-valve multicylinder engine.multicylinder engine.

The system employs the hydraulic pendulum principle, which The system employs the hydraulic pendulum principle, which contributes to low hydraulic energy consumption.contributes to low hydraulic energy consumption.

The electro hydraulic valve train is integral with the cylinder head, The electro hydraulic valve train is integral with the cylinder head, which lowers the head height and improves the engine packaging.which lowers the head height and improves the engine packaging.

Review of the benefits expected from a camless engine points to Review of the benefits expected from a camless engine points to substantial improvements in performance, fuel economy, and substantial improvements in performance, fuel economy, and emissions over and above what is achievable in engines with emissions over and above what is achievable in engines with camshaft-based valve trains.camshaft-based valve trains.

The development of a camless engine with an electro hydraulic The development of a camless engine with an electro hydraulic valve train described in this report is only a first step towards a valve train described in this report is only a first step towards a complete engine optimization. Further research and development complete engine optimization. Further research and development are needed to take full advantage of this system exceptional are needed to take full advantage of this system exceptional flexibility. flexibility.