A two stroke internal combustion engine, where fuel is injected using high pressure air injection, along with high pressure pre-compressed air. The fuel-air is ignited, and the piston pushed.
During the "compression" cycle the piston only pushes out the fumes, without compressing air for the next cycle.
Essentially this works like a four stroke engine with the induction and compression strokes removed.
___
This is a solution for smaller "home based" low cost wind energy storage.
Using plastic pipes inserted in the ground high pressure compressed air is accumulated from 15-50 kw wind turbines. Then used to enhance an engine with a small amount of fuel retrieving much of the energy from the pneumatic stored power.
For better efficiency a slow diesel engine could be used. This compressed air is then used to generate electricity using the Compressed Fuel-Air Engine.-- pashute, Mar 11 2011 Air Hybrid engine http://www.gizmag.com/go/5585/ [The_Saint, Mar 11 2011] Like this... http://en.wikipedia.org/wiki/Commer_TS3Compressed air 2 stroke diesel [Twizz, Mar 11 2011] Interesting engine http://www.tourengine.comWith a separate cylinder for compression. Makes for much higher efficiency. [pashute, Aug 22 2011] Wouldn't it be cleaner to use the air alone in an air motor?-- ldischler, Mar 11 2011 Baked except for the specific air pressure source:
The opposed piston 2 stroke diesels used in the Commer vans used a cycle as described. They had an engine driven compressor, but a static version could use any air supply.
The opposed piston engine has the advantage of improved scavenging. With the exhaust ports at one end of the cylinder and inlet at the other, there is very little mixing.-- Twizz, Mar 11 2011 we make the engine more efficient by getting elves to do part of the work.-- WcW, Mar 11 2011 So this is a spark ignition setup then?
To get significant power out of this you'd need to be compressing to a fair pressure. Filling the cylinder to 12bar would give you more or less equivalent to a NA petrol engine for start-of-combustion conditions (and therefore power availablility).
The worry for me would be the losses through your inlet system, to charge the cylinder from TDC you'll need a large flowrate through your intake valves.-- Skrewloose, Mar 11 2011 Ldisch, air engines are extremely inefficient , WCW please add a + to the community of ridiculing, Twizz and Saint - thanks(!) I'm looking into those. I just contacted Scuderi, getting them interested in renewable wind energy. I'll post here if any advance.-- pashute, Mar 13 2011 pashute how it the world does it make sense to use a perfectly good source of energy like a wind turbine to "increase the efficiency" of a diesel piston engine. It's like throwing light bulbs on a fire to make it brighter.-- WcW, Mar 13 2011 Not exactly. It's using much less gas. It's like fanning air at a low burning fire to get big flames.
Turns out this idea is deeply baked at large-scale at least. Just re-read CAES carefully on wikipedia. They use the compressed gas in the gas turbine of power plants.
So my proposal is to downscale it. Then anybody who has a small roof for solar power or a fair wind for a wind turbine, can store power without batteries, and get back its worth, when you need it.
Perhaps it would even be worth buying low rate nighttime electricity and then creating your needed electricity yourself in the daytime!-- pashute, Mar 13 2011 I agree that "use forced induction" isn't an idea with even a spark of novelty. Storing the motive energy from a turbine in a pressurized gas is also not a new idea. Where we part ways is with the notion of using that perfectly good stored energy to "help" a system that needs no help at all. The energy you will waste "boosting" your diesel generator would yield less than you would gain by using it to directly power a small generator and far less than you would gain by using a turbocharger or a conventional induction diesel motor. Induction represents only a very small inefficiency in the overall inefficiency of an internal combustion engine.-- WcW, Mar 13 2011 random, halfbakery