ok easy question what is knock? Thanks
06-28-2002, 11:53 AM
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Re: ok easy question what is knock? Thanks
Spark knock? As in detonation?
Occurs when the fuel starts burning from more than one location (uncontrolled) and the flame fronts meet. The noise is the flame fronts meeting.
Occurs when the fuel starts burning from more than one location (uncontrolled) and the flame fronts meet. The noise is the flame fronts meeting.
06-28-2002, 01:34 PM
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Re: Can you put that in layman's terms for me? details?
The fuel in the cylinder is supposed to be ignited by the spark plug when the computer says it's time for spark. When detonation occurs, something else in the cylinder ignites the fuel (piece of hot carbon, glowing hot edge on a piston or compression that is too high [too much turbo boost]).
So, the fuel ignites somewhere in the cylinder where it's not supposed to by some element... then the spark plug fires and ignites fuel near it. When fuel burns it "runs" outward from the source of ignition consuming nearby fuel. So you have two flames running toward each other with a pressure wave in front of them (hot buring gas is expanding in a compressed space, VERY high pressure). When those pressure waves smash into each other there is a huge spike in the cylinder pressure... high enough to break spark plugs, crack pistions (or burn holes through them) and bend connecting rods. The noise is the force of that collision resonating through the engine.
So, the fuel ignites somewhere in the cylinder where it's not supposed to by some element... then the spark plug fires and ignites fuel near it. When fuel burns it "runs" outward from the source of ignition consuming nearby fuel. So you have two flames running toward each other with a pressure wave in front of them (hot buring gas is expanding in a compressed space, VERY high pressure). When those pressure waves smash into each other there is a huge spike in the cylinder pressure... high enough to break spark plugs, crack pistions (or burn holes through them) and bend connecting rods. The noise is the force of that collision resonating through the engine.
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