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hero live
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Why does higher intake manifold pressure results in increase in the degree of spark advancement? Similarly, why is the torque higher for higher intake manifold pressure?
hero live said:Why does higher intake manifold pressure results in increase in the degree of spark advancement?
I assume you mean output torque from the engine.Similarly, why is the torque higher for higher intake manifold pressure?
billy_joule said:It doesn't.
It increases the need for advancement but does not result in it.
That need may be meet by the methods found here:
http://en.wikipedia.org/wiki/Ignition_timing
Although, in my opinion, it is more because of the denser fuel-mixture (like for the added turbo) than because of a change in air-fuel ratio.The ignition timing is also dependent on the load of the engine with more load (larger throttle opening and therefore air:fuel ratio) requiring less advance (the mixture burns faster).
hero live said:I don't get this part. How does increased intake manifold pressure lead to need for spark advancement maximum brake torque timing?
Intake manifold pressure is the measure of air pressure inside the intake manifold of an engine. It is typically measured in units of pressure, such as pounds per square inch (psi) or kilopascals (kPa).
The amount of air pressure in the intake manifold affects the amount of air that can be drawn into the engine. This, in turn, affects the amount of fuel that can be mixed with the air and the overall efficiency of the combustion process. Too little or too much intake manifold pressure can result in decreased engine performance.
Spark timing is the precise timing of when the spark plugs ignite the air-fuel mixture in an engine's cylinders. It is controlled by the engine's computer and determines when the fuel is ignited and how long the spark lasts.
The timing of the spark affects the efficiency of the combustion process and, therefore, the overall performance of the engine. If the spark timing is off, it can result in decreased power, fuel economy, and emissions.
The intake manifold pressure and spark timing are closely related as they both affect the combustion process in an engine. The timing of the spark is often adjusted based on the level of intake manifold pressure to optimize engine performance and efficiency.