Diesel engine braking idea
#1698557
11/13/14 03:34 PM
11/13/14 03:34 PM
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Joined: Jan 2003
Posts: 7,521 Minnesota
Hemi_Joel
OP
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OP
master
Joined: Jan 2003
Posts: 7,521
Minnesota
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Exhaust brakes are available for diesels to help get down long steep grades safely without cooking the brakes. They work by choking off the exhaust flow, turning the engine into a compressor. But they are expensive and trouble prone. Gas engines have decent engine braking, just by closing the throttle valve, cutting off the air flow into the engine, turning it into a vacuum pump. So how about installing a big throttle valve on the turbo inlet, or on the intake manifold inlet for use as an engine brake? Is there any reason that wouldn't work?
[img]http://i.imgur.com/boeexFms.jpg[/img]31 Plymouth Coupe, 392 Hemi, T56 magnum RS23J71 RS27J77 RP23J71 RO23J71 WM21J8A I don't regret the things I've done. I only regret the things I didn't do. "Wise men talk because they have something to say; fools because they have to say something. ~ Plato"
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Re: Diesel engine braking idea
[Re: Hemi_Joel]
#1698560
11/13/14 09:23 PM
11/13/14 09:23 PM
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Joined: Jan 2005
Posts: 12,478 Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
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Posts: 12,478
Kalispell Mt.
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If you did it after the turbo and slammed it shut then the pressure between the turbo and throttle plate would spike through the roof, maybe make the turbo try to spin backwards or blow off the hose clamps, especially since the exhaust pressure also drop seriously fast I think the turbo gas engines with a blow through set up have a pressure relief system.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Diesel engine braking idea
[Re: BigDawg72]
#1698562
11/13/14 11:58 PM
11/13/14 11:58 PM
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Joined: Jan 2003
Posts: 8,222 Plymouth, MI
Blusmbl
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Posts: 8,222
Plymouth, MI
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The modern stuff just uses the variable geometry turbo to provide engine braking, it works pretty well. I think all of the current model year 3/4 and 1 ton trucks have a turbo-based exhaust brake, which is not trouble prone like the older external hardware.
All also have intake throttles but don't use them for engine braking purposes because you'd then also need a compressor side bypass valve, which diesels don't have.
'18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118
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Re: Diesel engine braking idea
[Re: Hemi_Joel]
#1698563
11/14/14 04:10 PM
11/14/14 04:10 PM
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Joined: Jan 2003
Posts: 26,470 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
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Posts: 26,470
Rio Linda, CA
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I would think the huge difference in the gas/diesel compression ratios would limit the gas engine's effectiveness as a brake.
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Re: Diesel engine braking idea
[Re: BigDawg72]
#1698564
11/14/14 07:07 PM
11/14/14 07:07 PM
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Joined: Jan 2005
Posts: 12,478 Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
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Posts: 12,478
Kalispell Mt.
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I think they actually work by opening the ex valve just after TDC on the power stroke so the compression does not push the crank down right after it slowed it via compression on the compression stroke. Thats why they are so noisy.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Diesel engine braking idea
[Re: HotRodDave]
#1698565
11/15/14 05:22 AM
11/15/14 05:22 AM
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Joined: May 2003
Posts: 1,751 Graham, WA
Polarapete
top fuel
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top fuel
Joined: May 2003
Posts: 1,751
Graham, WA
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The exhaust brake on my 2002 CTD was a butterfly in the exhaust after the turbo. I had to clean it once and the little shuttle valve that controlled it stuck once and crippled the engine (no power at all) I loved the sound of it in action and it was very effective when pulling and stopping the 8,000# travel trailer we had. There was no exhaust valve lifting on that engine.
1986 Dodge Ramcharger 440 2wd, Bracket Racer Under Construction 1998 Ram 2500 QuadCab, new daily driver. 2008 Honda Element 2014 Carry-On 7x14 Cargo Trailer
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