How To Build A 100 Mpg Car

[Lil4X]

Typically diesel engines will have a manually actuated "air shutter" that closes the intake to the blower or engine, shutting off oxygen to the combustion process in case of a runaway.

 

[ross]

Lil4X
I really don't know as much about diesel as I'd like to.
Is this the case for very many runaway diesel incidents? .

The two biggest differences between gas and diesel engines are.
#1 of course gas engines require a spark plug to initiate the combustion cycle, where as diesels rely on compression, as fuel is not introduced until Top Dead Center or thereabouts.
#2 The throttle of a gas engine controls the amount of air introduced into the engine, whereas the throttle of a diesel controls the amount of fuel into the engine.
Other than that they are both internal combustion engines.
Either 2 stroke or 4 stroke.
I have a friend who had a VW diesel rabbit pickup who hired a mechanic to replace the engine with a gas engine because he didn't know how to work on a diesel engine. I asked him, 'So you added a carburetor, a distributor with points and a condenser, and spark plugs, all of which a diesel doesn't have. Tell me how you simplified things, and made it easier to work on?'
He had no reply.

 

[NSTG8R]

Typically diesel engines will have a manually actuated "air shutter" that closes the intake to the blower or engine, shutting off oxygen to the combustion process in case of a runaway.

Well, all I can speak to is my 7.3L Powerstroke, but its' a straight shot from the air filter to the turbo, and from the turbo straight to the intake manifold (no intercooler). If you want to manually shut down the incoming air, you'd better have a softball handy to jam in the intake duct. RPM's completely controlled by the amount of fuel dumped in by the injectors. All this talk about diesel's just reminded me that if I want to drive the truck once the weather gets cold, I need to get a couple bottles of Diesel Clean in the tanks to keep the fuel from gelling! Diesel's hate cold weather!

 

[wheaters]

It's not unknown for a diesel with failed oil seal on the turbo charger to begin eating it's own engine oil.

 

[Jim H]

It's not unknown for a diesel with failed oil seal on the turbo charger to begin eating it's own engine oil.

I'll stay with a gas powered engine, thanks.

 

[wayne kemp]

It's not unknown for a diesel with failed oil seal on the turbo charger to begin eating it's own engine oil.

Take a good look. I think we all know why the van is smoking. Check out the passengers.

 

[wheaters]

Take a good look. I think we all know why the van is smoking. Check out the passengers.

Down, boy!

 

[AriLea]

I've heard about similar "uncontrolled acceleration events" where the presence of a combustible gas enters an engine's combustion chamber providing additional "fuel" to the engine. It can happen - it's not just an old industrial legend . . . your nose is not a good judge of the presence of these gases.

Back in the '70's I worked with a pan-industrial task team seeking to find exposure limits and safe working concentrations of H₂S. Not only was this gas almost instantly poisonous, its concentrations were remarkably low to produce deadly effects almost immediately . . . down around 800 ppm. But exposure over a longer period can be lethal at far lower concentrations. There have been multiple industrial deaths due to a man going down in an H₂S environment, and a succession of would-be "rescuers" dying in an attempt to pull the man into fresh air and being poisoned themselves.

What makes H₂S supremely deadly is that it overwhelms your sense of smell at very low concentrations. The gas gets into your bloodstream and blocks the ability of cells to take up oxygen and you die rather quickly of asphyxiation. You and I can smell the rotten-egg odor of H₂S at extremely low concentrations, but our sense of smell quickly goes "blind" to the odor when the concentration is prolonged or only slightly elevated - at less than 150 ppm for five minutes. It's been said - with a great deal of truth - that if you can smell rotten eggs, you're probably safe but you should be wary . . . when you can't smell it any more, RUN!

Propane and other gases affect your olfactory sense the same way - at elevated concentrations you go "nose blind" rather quickly even before explosive concentrations are reached . . . and think you are safe. Then . . . . well, BOOM! An engine taking in "fuel" in the ambient air will "run away" - a very dangerous proposition for anyone in the vicinity. Gas, diesel, and even gas turbine engines can experience this when significant concentrations of combustible gas is present in air. Most of the time this level of concentration is far above being compatible with human life, but in enclosed spaces, as the cause of a runaway, it represents a set of hazards all its own.

Well, I can see why the EPA might get their noses bent out of shape just a bit. The H2S addition may have other useful attributes associated with flame propagation etc. But I would think other chemicals could do that with less dangerous chemical after effects.