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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]
Valve timing and the valve profile are continuously altered according to conditions and engine load. 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.
The Alfa Romeo Twin Spark engine, introduced in the 1987 Alfa Romeo 75, also uses variable valve timing. [3] [4] The Alfa system varies the phase (not the duration) of the cam timing and operates on the inlet camshaft. [5] Alfa Romeo's variator is a cylindrical chamber that contains a pressure chamber and piston along with helical splines.
The AMB series engine was an inline 4-cylinder engine, manufactured from 2001 to 2003 by the Volkswagen Group in Ingolstadt, Germany as a replacement for the earlier 1.8T engines, such as the AEB-type engine. As opposed to the AEB, the AMB had thinner wrist pins (19 mm instead of 20 mm).
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.
SOHC design (for a 1973 Triumph Dolomite Sprint) . The oldest configuration of overhead camshaft engine is the single overhead camshaft (SOHC) design. [1] A SOHC engine has one camshaft per bank of cylinders, therefore a straight engine has a total of one camshaft and a V engine or flat engine has a total of two camshafts (one for each cylinder bank).
The disadvantage of this system is its cost. Even though it is a fairly simple device it requires very accurate helical machining and very careful assembly. The helical camshaft prototypes typically cost about $1500 in machining and materials. [citation needed] This figure would reduce greatly in production. The cost of the helical camshaft is ...
VCT on the intake camshaft is used primarily for increasing engine power and torque as the PCM is able to optimize the opening of the intake valves to match the engine conditions. [ 2 ] VCT is used in Ford's Triton 5.4L 3-valve V8 engine, the Australian Barra 182 and 240 Inline-6s , and Ford's 4.6L 3-valve V8 engine used in the 2006-2010 Ford ...