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Pressure in cylinder pattern in dependence on ignition timing: (a) - misfire, (b) too soon, (c) optimal, (d) too late. In a spark ignition internal combustion engine, ignition timing is the timing, relative to the current piston position and crankshaft angle, of the release of a spark in the combustion chamber near the end of the compression stroke.
The CEC also controlled ignition timing using information from the fuel-control section and an engine knock sensor on the intake manifold. The CEC module itself (the most common version of which is the "AMC MCU Super-D") was manufactured for AMC by Ford Motor Company, and worked with a Duraspark ignition system. Although built by Ford, the CEC ...
The functional objective for the crankshaft position sensor is to determine the position and/or rotational speed of the crank. Engine Control Units use the information transmitted by the sensor to control parameters such as ignition timing and fuel injection timing. In a diesel, the sensor will control the fuel injection.
In this case, the timing comes from the fuel injection system. Very small model engines for which simplicity and light weight is more important than fuel costs use easily ignited fuels (a mixture of kerosene, ether, and lubricant) and adjustable compression to control ignition timing for starting and running.
This point is generally just before the piston reaches the top of its compression stroke. The contact breaker is often mounted on a plate that is able to rotate relative to the camshaft operating it. The plate is most typically rotated by a centrifugal mechanism, thus advancing the ignition timing (making the spark occur earlier) at higher ...
With early induction and ignition systems the compression ratios had to be kept low. With advances in fuel technology and combustion management, high-performance engines can run reliably at 12:1 ratio. With low octane fuel, a problem would occur as the compression ratio increased as the fuel was igniting due to the rise in temperature that ...
For example, if the static compression ratio is 10:1, and the dynamic compression ratio is 7.5:1, a useful value for cylinder pressure would be 7.5 1.3 × atmospheric pressure, or 13.7 bar (relative to atmospheric pressure). The two corrections for dynamic compression ratio affect cylinder pressure in opposite directions, but not in equal strength.
In the early days of side valve heads this was not done and a much lower compression ratio had to be used for any given fuel. Also such engines were sensitive to ignition advance and had less power. [4] Knocking is more or less unavoidable in diesel engines, where fuel is injected into highly compressed air towards the end of the compression ...