Why does a diesel make noise?
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Why does a diesel make noise?
I recently purchased a 4x4 Excursion. My first diesel. I have asked many people this question and even researched it on the internet but I cannot find a clear answer. Why does the diesel engine clatter? Don't get me wrong, I love the sound, but as an inquisitive person, I must find out the answer to this question.
Thanks in advance!
Matt
Thanks in advance!
Matt
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From: SF Bay area
Why does a diesel make noise?
Hi Matt, the reason a diesel makes noise is because it runs different that a gas engine. in gas, the spark ignites the air/fuel mixture, and the explosion "travels". In a diesel the air is compressed at a higher ratio than a gas engine, then fuel oil (or diesel fuel as we know it) is shot into the cylinders (via injectors). the resulting explosion is almost like a "detonation" or pinging in a gas engine, and that is why diesels are noisy. This was explained to me about 23 years ago when I was a certified auto mech. so I hope I am not too far off.
Wayne
Wayne
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Why does a diesel make noise?
I myself don't know much about either engine, but I believe diesels are generally larger than gas engines. So, with that in mind the explosion or detonation from a deisel would be bigger than with a gas engine and harder to muffle. I don't think I have ever heard a silent explosion outside an engine. The only gas engine that I know of as being silent (and not becase of being muffeled) are flathead engines. To make this eaiser to understand, I think gas engines are simply muffeled more. However, I could be wrong.
Logan
Logan
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Why does a diesel make noise?
Thanks Wayne and Logan, I can follow just what you said about "pinging" in a gas engine. To me that is almost what it sounds like, in fact, I was driving the other day and accelerated a little and heard the "ping", it took me back to my gas days. I think the engine is awesome and will never drive a gas again! Thanks also to this site, I get a lot of great info here.
Matt
2000 Excursion 4x4 PSD limited.
Matt
2000 Excursion 4x4 PSD limited.
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Why does a diesel make noise?
The reason a diesel engine makes noise(rattles) is from what is refered to as "valve overlap" this is the split second in which both intake and exhaust valves are open,the effect is refered to as "scavenging" this is using intake air to push remaining exhaust gas out of the combustion chamber and this coupled with fuel injection timing causes an increase or decrease
in rattle depending on advanced or retarded timing
in rattle depending on advanced or retarded timing
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Why does a diesel make noise?
gas engines also have valve overlap, and alot of diesels all smaller than gas engines(PSD is only 444ci) so those are not valid reasons for the noise. the reason is because the combustion of the fuel is not controlled by an ignition system. that means that the cylinders don't actually fire at the correct, or the same point every time.
John,
GM writes my paycheck, but All I drive is FORDS
John,
GM writes my paycheck, but All I drive is FORDS
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Why does a diesel make noise?
I have a similar question, Why are the newer powerstrokes in the new superdutys quieter than the previous powerstrokes that were in the older body style? I have a '99 and a '01 Superduty both with the PSD and they both run so nice and quiet compared to the older ones.
Thanks for whatever thoughts you might have.
Chad
Thanks for whatever thoughts you might have.
Chad
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Why does a diesel make noise?
The reason the new diesel engines are quiter is the splitshot injection. This injector shoots two shots of fuel into each cylinder. One slightly before ingition causing preigntion before the main injecton of fuel this makes the engine quiter. Note...some of the new diesel engines suffer from a Knock-Cackle resulting from the #8 injector being starved for fuel resulting from the firing of the #6 cylinder so close to the firing of the #8. Ford came out with the Long Firing #8 (LL#8) to solve this problem by making the #8 injector fire longer. But this did not solve the problem. So if you have one of the engines that are only knocking on the number 8 cylinder there is a TSB out there that attempts to fix it. But if you have it done be prepaired to lose some power and fuel economy on the low end.
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