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In spark-ignition internal combustion engines, knocking (also knock, detonation, spark knock, pinging or pinking) occurs when combustion of some of the air/fuel mixture in the cylinder does not result from propagation of the flame front ignited by the spark plug, but when one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.
Wide open throttle or wide-open throttle (WOT), also called full throttle, is the fully opened state of a throttle on an engine (internal combustion engine or steam engine). The term also, by extension, usually refers to the maximum-speed state of running the engine, as the normal result of a fully opened throttle plate/butterfly valve.
The throttle on a gasoline engine is typically a butterfly valve. In a fuel-injected engine, the throttle valve is placed on the entrance of the intake manifold, or housed in the throttle body. In a carbureted engine, it is found in the carburetor. When a throttle is wide open, the intake manifold is usually close to ambient atmospheric pressure.
The advent of concern about fuel economy and emissions had major impacts on engine design. Some of the trade-offs reduced throttle response. Most new cars employ a drive-by-wire system, which includes electronic throttle control and can itself either reduce or increase throttle response (Depending on whether or not it's being employed on a performance car).
The first, called Combined Combustion System or CCS, is based on the VW Group 2.0-litre diesel engine, but uses homogeneous intake charge. It requires synthetic fuel to achieve maximum benefit. The second is called Gasoline Compression Ignition or GCI; it uses HCCI when cruising and spark ignition when accelerating.
A typical ETC system consists of three major components: (i) an accelerator pedal module (ideally with two or more independent sensors), (ii) a throttle valve that can be opened and closed by an electric motor (sometimes referred to as an electric or electronic throttle body (ETB)), and (iii) a powertrain or engine control module (PCM or ECM). [4]
Some engine control units (ECUs) also control the throttle position by electronic throttle control (ETC) or "drive by wire" systems, and if that is done, the position sensor is used in a feedback loop to enable that control. [1] Related to the TPS are accelerator pedal sensors, which often include a wide open throttle (WOT) sensor.
A bad crank position sensor can worsen the way the engine idles, or the acceleration behaviour. If the engine is revved up with a bad or faulty sensor, it may cause misfiring, motor vibration or backfires. Acceleration might be hesitant, and abnormal shaking during engine idle might occur. In the worst case, the car may not start.