Turbo Diesel Waste Heat Steam Boost Enhancer Thread

[ConnClark]

By popular demand I have created the Turbo Diesel Waste Heat Steam Boost Enhancer Thread.

The idea is simple. Use exhaust heat after it flows through the turbo to boil water to create steam. Feed this steam into the exhaust manifold. The additional pressure and mass will increase boost which ups efficiency of the engine.

Assuming I can get a friend I have that loves steam engines to help me, I will implement it as a closed one pass system. I will place a water reservoir below the level of the exhaust manifold. I will then run brass or copper tubing from the reservoir to the base of the downpipe of my exhaust. once there I will wrap the piping around the tubing up to the exit of the turbo. The pipe will then tee. One branch will feed into the exhaust system and the other will go back to the reservoir to equalize the pressure.

This set up will not boil as much water as it can with the heat available however it will use the water to its maximum effect. Since the water level will be below the manifold. Steam flowing through the copper or brass tubing above the water level will continue to rise in temperature until it feeds into the exhaust manifold. This will minimize the temp drop of the exhaust gasses when mixed with the lower temp steam. I will also preheat the reservoir with engine coolant.

Every thing in the system will be at exhaust manifold pressure so I figure that designing the system to withstand 70 psi will be more than enough.

[Christ]

Really looking forward to this!

[Daox]

Very cool. I can't wait to see how it works.

[Funny]

I can see this working somewhat, but how will the power generated be used, and will this power generated overcome efficiency loss of the additional weight that you are going to impose on the system? Good idea, let's see if it bears fruit!

[Daox]

Funny has a good point. Have you thought about regulating the steam usage? So you can use it more while accelerating, and save up power when cruising at low speeds?

[ConnClark]

Originally Posted by Daox

Funny has a good point. Have you thought about regulating the steam usage? So you can use it more while accelerating, and save up power when cruising at low speeds?

By mounting the reservoir forward of the tubing water will slosh backwards while accelerating and thus farther up the coiled tubing. The tubing that is normally out of the water should be heated hotter than the tubing that has water in it and thus help flash the water to steam. Also burning more fuel will accelerate steam production on its own.

Braking will slosh the water forward and thus out of the tubing reducing steam.

Weight is a concern So I'll just start off with a half gallon reservoir to begin with. With the piping filled it will probably be about a gallon total.

I am investigating what it would take to top off the reservoir with another tank of water and a high pressure water pump.

[user removed]

The problem as I see it is the heat it takes to expand the steam will reduce the peak combustion chamber temperature and therefore efficiency.

Now if you can preheat the steam and introduce it in the precise amount necessary it may be possible to increase mileage through the expansion of superheated steam, when the expansion ratio gets very high.

The requires steam at about 8-900 degrees, temperatures that are very short lived in a diesel engine combustion event.

It should be interesting as the concept of recovering heat energy from the normally wasted exhaust gasses is technically correct, but the actual accomplishment of any improvement might require some serious work, technique, and fiddling and adjustment.

I really like the passive system concept, following the keep it simple principle, and hope you succeed, so I can try it in one of my cars.

regards
Mech

[Daox]

I believe hes planning on injecting the steam back into the turbocharger before the exhaust turbine, not on the intake side.

[Bicycle Bob]

I can't see any potential for savings here. An increase in induction pressure from an increase in backpressure sounds like tail-chasing.

[user removed]

I reread it Daox, and if he does that it will probably destroy the turbocharger.

regards
Mech