CAMLESS ENGINE

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To eliminate the cam, camshaft and other connected mechanisms, the Camless engine makes use of three vital components – the sensors, the electronic control unit and the actuator.

ELECTRONIC CONTROL UNITSENSORS ACTUATORS

Mainly five sensors are used in connection with valve operation.

1. For sensing the speed of the engine.2. For sensing the load of the engine.3. exhaust gas sensor.4. valve position sensor.5. current sensor.

The elastic properties of a compressed hydraulic fluid, which, acting as a liquid spring, accelerates and decelerates each engine valve during its opening and closing motions. This is the principle of the hydraulic pendulum.

During the valve opening, the high-pressure solenoid valve is open, and the net pressure force pushing on the double-acting piston accelerates the engine valve downward. When the solenoid valve closes, pressure above the piston drops, and the piston decelerates pushing the fluid from the lower volume back into the high-pressure reservoir. Low-pressure fluid flowing through the low-pressure check valve fills the volume above the piston during deceleration. When the downward motion of the valve stops, the check valve closes, and the engine valve remains locked in open position. The process of the valve closing is similar, in principle, to that of the valve opening.

OPERATION

Varying the activation timing of both solenoids varies the timing of the engine valve opening and closing.

Valve lift can be controlled by varying the duration of the solenoid voltage pulse. Changing the high pressure permits control of the valve acceleration, velocity, and travel time.

The valve can be deactivated during engine operation by simply deactivating the pair of solenoids which control it.

Valve motion control

Infinitely varying valve timing.

Decreases fuel consumption.

The amount of engine oil required is also reduced because no lubrication for valve actuating mechanism.

increases overall valve train efficiency by eliminating the frictional losses of the camshaft mechanism.

Advantages:

Conclusions: 1. An electro hydraulic camless valve train was developed for a camless engine. Initial development confirmed its functional ability to control the valve timing, lift, velocity, and event duration, as well as to perform selectively variable deactivation in a four-valve multicylinder engine.2. The system employs the hydraulic pendulum principle, which contributes to low hydraulic energy consumption.3. The electro hydraulic valve train is integral with the cylinder head, which lowers the head height and improves the engine packaging.4. Review of the benefits expected from a camless engine points to substantial improvements in performance, fuel economy, and emissions over and above what is achievable in engines with camshaft-based valve trains.

REFERENCES:

1. Schechter MM, Levin MB Camless engine. SAE article.

2. Article in autospeed on camlessengines.

QUERIES??

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