Audi improves power and efficiency with new valvelift system

Audi News. Engines - An Introduction.

VVT: What is Variable Valve Timing And How It Really Works?

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The "Clemson camshaft" is of this type. Toyota says this system is good for a 10 percent gain in both horsepower and fuel economy. This system utilities the engine lub oil to control the closure of inlet valve.

Find More Posts by hoTTub. Without variable valve timing or variable valve lift , the valve timing is the same for all engine speeds and conditions, therefore compromises are necessary.

VVT, what are the pro's/con's?

Select a Year GO. Some of these modifications and or parts are intended for off-road use only and may violate Federal or your State's emissions standards.

The exhaust camshaft on the cylinder bank shown remains in this position as long as the Camshaft Adjustment Valve 1 Exhaust N solenoid is not actuated. The adjustment variation between these two positions is 22 degrees of crankshaft angle. Two of the ways in which this is achieved in a modern machine is through the use of Variable Valve Lift and Variable Valve Timing.

Variable Valve Timing Actuator

Comments 3 Herb Score Mar 6, at 3: Back to question. With the Variable Valve Lift system, the camshaft on the exhaust side of the car has two different cam profiles for each valve.

To retard the intake camshaft on the cylinder bank shown, the Motronic Engine Control Module J actuates Valve 1 for Camshaft Adjustment N, which opens the gallery for timing retardation by moving the control piston. This, in turn, may prevent the phaser from getting enough oil pressure to advance the cam normally.

Portal Category. Forgot Password? About Us Contact Us For e. Related Articles. This causes the intake and exhaust valve rockers to be pulled away from their normal lobes and to follow the profile of the third rocker lobes. At higher engine speeds, valve lift and duration are increased to add more power.

Monday thru Friday 9: The control map in the Motronic Engine Control Module J determines the intake camshaft adjustment using this camshaft position information as well as engine load, speed, and coolant temperature readings. Street engines spend most of their time from idle to about RPM with occasional bursts to RPM, so street cams are typically ground with less duration and overlap to increase low end torque. Minor point — the solenoid oil control valve more specifically does not quite work in the way described.

Relevant discussion may be found on the talk page. Early variable valve timing systems used discrete stepped adjustment.