Water/alky injection in a diesel

[beef_bourito]

I was just wondeing if you could use a wate or alcohol injection system with a diesel engine, and if there would be any gains. With water injection i don't really see any problems, it might cool the combustion chamber a bit but it would raise the compression, it would also cool the intake allowing for more air to be put into the cylender and therefore you can use more fuel. with alcohol injection think the same hold true but the problem that i see with that is that the alcohol could ignite on the compression stroke and creat knock, although is this at all significant? i mean you don't inject much alcohol. basicaly i want to know advantages/disadvantages to water/alcohol injection and whether or not it's doable.

[curtis73]

Originally Posted by beef_bourito

I was just wondeing if you could use a wate or alcohol injection system with a diesel engine, and if there would be any gains. With water injection i don't really see any problems, it might cool the combustion chamber a bit but it would raise the compression, it would also cool the intake allowing for more air to be put into the cylender and therefore you can use more fuel.

Water wouldn't help. Raising compression won't do much for a diesel (and if its a turbo might actually hinder things). Also, since diesels don't have a throttle and are exposed to ambient air, the water would most likely just occupy space that could contain oxygen. It would however lower EGTs which is almost always a good thing.

with alcohol injection think the same hold true but the problem that i see with that is that the alcohol could ignite on the compression stroke and creat knock, although is this at all significant? i mean you don't inject much alcohol. basicaly i want to know advantages/disadvantages to water/alcohol injection and whether or not it's doable.

The alcohol might pre-ignite which would reduce power. I've never read anything about alcohol in diesels so I'm not sure. Anyone know its activation energy?

[beef_bourito]

so how do you control engine speeds in a diesel? do you control the gas?

[beef_bourito]

and what do you mean they are exposed to ambient air?