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For improved responsiveness on cold starts, VarioCam Plus raises the amount of lift and retards valve timing. At medium revs with minimal loads, the valve lift is lowered and timing advanced to help minimize fuel consumption and emissions. For maximum power and torque, the lift is raised and the timing is advanced.
An engine requires large amounts of air when operating at high speeds. However, the intake valves may close before enough air has entered each combustion chamber, reducing performance. On the other hand, if the camshaft keeps the valves open for longer periods of time, as with a racing cam, problems start to occur at the lower engine speeds.
For twin-cam or DOHC engines, VCT was used on either the intake or exhaust camshaft. (Engines that have VCT on both camshafts are now designated as Ti-VCT.↓) The use of variable camshaft timing on the exhaust camshaft is for improved emissions, and vehicles with VCT on the exhaust camshaft do not require exhaust gas recirculation (EGR) as retarding the exhaust cam timing achieves the same ...
The active valve control system (AVCS) is an automobile variable valve timing technology used by Subaru. It varies the timing of the valves by using hydraulic oil pressure to rotate the camshaft, known as "phasing", [1] in order to provide optimal valve timing for engine load conditions. The system is closed loop using the camshaft sensors ...
In most piston engines, the camshaft(s) are mechanically connected to the crankshaft. The crankshaft drives the camshaft (via a timing belt, timing chain or gears), which in turn actuates the intake and exhaust valves. [1] These valves allow the engine to inhale air (or an air/fuel mixture) and exhale the exhaust gasses. [2]
There have been two main versions of this engine. The first version made 187 hp (139 kW) and 145 lb⋅ft (197 N⋅m) torque. This engine was used by Nissan from 1997 to 2001. It is found in the Nissan Primera, Nissan Bluebird, and the Nissan Wingroad. The second variant of the SR20VE is found only in the 2001 and later P12 Nissan Primera.
The application of intake valve type roller rocker arm, which reduces the friction produced when the camshaft is running. The application of Dual VVT-i system, which adjusts timing on both intake and exhaust camshafts. Improved cylinder head design. Longer intake valve, which improves lower-end torque. [12] Compatible with E20 fuel (Dual VVT-iE ...
The cam can be seen as a device that converts rotational motion to reciprocating (or sometimes oscillating) motion. [clarification needed] [3] A common example is the camshaft of an automobile, which takes the rotary motion of the engine and converts it into the reciprocating motion necessary to operate the intake and exhaust valves of the cylinders.