What exactly makes all the noise in a diesel motor?

[John Berger]

This is an outstanding thread. My engine definitely "smooths" out after towing for awhile. I love a technical description of what sounds so good bouncing off of the side of my house at 5:30 in the morning. Oo.

 

[Peterbilt379CJ]

Again, I do agree, this is a great post. Pilot injection in use now in small diesels helps reduce noise as RBattelle has stated. What I meant to say was that a engine with a pre-combustion chamber is quieter than a direct injection motor.



And yes, a high compression ratio will make a lot of noise, look at the injection timing on almost all diesels.

CAN YOU FIGURE OUT WHERE I AM GOING WITH THIS?



Yes, I do agree with you that gears do make a whineing noise but I did not say the gears where making noise, I said that a lot of noise is transmitted through the gears.



I want to say this; this is a great discussion.



There is nothing like learning and teaching at the same time without people getting nasty. Just a friendly open discussion.



Will catch you all on the rewind... ... ... . 10-4?

 

[Whitmore]

Today comming out of the store with my lil woman a Cummins idled by and my wife says listen to them pistons in there swaping holes I asked her how come they are so noisy and she said it was part of the combustion process I said yep those sparkplugs have a big job and she replied that only gas engines have sparkplugs and diesels fire under compression



Let me tell you what I was so proud of this woman I took her home and gave her the Texaco treatment ( thats where you put them up on the rack and lube their chassy )



I Love that woman

 

[C. Harlan]

I think they did away with precombustion chambers with the last ones being in the 94 Indirect injected 7. 3 fords. in 95 was the first powerstroke motor, and the ones that just say Turbo Diesel are the IDI motors.

 

[Prairie Dog]

What makes most of the noise? In a 6. 0 PSD most of the noise comes from the infuriated driver :{ .

 

[Vaughn MacKenzie]

Here's a picture of an old Lister diesel showing what a precombustion chamber looks like. Engineers have gone away from this design but they were useful in helping combustion clatter and improving efficiency for low injection pressure engines. But they aren't as efficient as "direct injection" which is common now.



On compression ratios, here's some interesting ones:



*My 1950 Chevrolet with 216 6cyl = 6. 0:1 CR

*1932 Chevrolet 6: "By increasing the CR to 5. 2:1, horsepower was increased from 46 to 60hp"



Oldsmobile Diesel: 22. 5:1 (High CR + crappy bottom end = rod chunker)

Rabbit Diesel 23:1



Vaughn