An idea to increase power/efficiency of a Natural Gas (CH4) Internal Combustion Engine (ICE).

While I was driving to In-N-Out, earlier today, an idea struck me as to how to improve the performance of a Natural Gas powered Internal Combustion Engine...

Essentially, the waste gases of a natural gas engine is water vapor and carbon dioxide with trace amounts of other pollutants.
A major waste product of the engine is heat, especially excess heat in the exhaust gasses. What do I define as excess heat in the exhaust? Quite simply it is heat above the point required to keep the water content of the exhaust in its vapor phase. At standard atmospheric pressure, it would be 100ºC. With an engine with a 12:1 compression ratio, this temperature would be at least 182ºC, plus a bit more for the motive power of the engine - so lets say around 200ºC.

The exhaust gases could be condensed to form mildly acidic but otherwise pure water. This water could be warmed by the engine's cooling system up to equal the temperature of the engine block, which would be a little under 100ºC. At the point of the engine cycle just after the intake valves close at roughly the point where compression begins, a small amount of this warmed water could be injected as a fine aerosol spray. The subsequent combustion of the natural gas could provide enough energy to also change the injected water into its vapor phase, increasing the post-combustion pressure within the engine, providing more motive power.

The key thing to do would be to monitor the temperature of the exhaust from the engine to ensure that there is excess heat within the system to vaporise the injected water so that the water is not injected at a time when there is insufficient energy to support it as it would likely result in reduced engine performance.

How well would this perform? Well, to be honest, I have not run any detailed numbers but I don't think it would be too far fetched to imagine this improving power by as much as 10%, maybe even significantly more. Increased performance would mean less time spent accelerating and perhaps less fuel to maintain steady velocity which both would mean significant gains in fuel efficiency.

What other uses for the condensed water can I think of? Perhaps some form of evaporative cooling system for the intake air? Another idea to entertain.

If only I had the time to play...

The cost of Natural Gas

It is quite amusing sometimes to look at official statistics: 4 times more natural gas is lost in storage and in the natural gas pipe network than is used for transportation.
This means that they (Sempra etc) could in theory sell natural gas for use in transportation for free and write it off as 20% increase in network storage losses.
However, the cost of fuel to owners of natural gas vehicles in California is up to 3 times higher than the cost of fuel to vehicle owners in Utah. Given that the wholesale price of natural gas is prroximately $9.03 per 1000 cu.ft. and the retail price to CNG vehicle owners in California is around $2.89 / gge (1 gge = 127.77 cu.ft.), then the natural gas companies have a profit margin of approximately 150%. If California is really serious about reducing pollution, natural gas vehicles needs to be encouraged since natural gas is the source fuel used by all hydrogen fuel cell vehicles, whether the natural gas is cracked in a converter at home, within the vehicle itself (natural gas fuel cell) or done industrially at the filling station. Price gouging by the natural gas suppliers needs to stop - CNG vehicle owners should not have to have a home filling station fitted just to avoid the inflated prices at the filling stations.