What materials would be necessary to allow gasoline engines to run at higher compressions with higher voltages

Question

It has been said that much energy goes to cooling the engine. But, if the engine was made of phenolic or something that could withstand extreme heat, could the spark voltage be higher, thereby limiting the fuel necessary(vapors verses liquid flow spray) to power a vehicle?

Answer 1

Limiting factor on increasing compression in  gasoline engine is the heat of compression causing detonation (pinging).  This is why diesel engines are more efficient than gasoline engines. Diesels use higher compression and a less volatile fuel.

Answer 2

If the spark current (energy) were much higher, the engine could heat *air* for expansion, but it would use up more energy than it produces.

Answer 3

The other answers are good. I would just point out a couple of things.

The spark in an engine acts to ignite the fuel/ air mixture. Once ignition is made the flame propagates by itself. Additional spark does not produce more power (although it can help maintain ignition in the case of stratified charge engines). As well, the voltage required is only sufficient to jump the sparkplug gap. It does not rise any higher than this since the breakdown voltage causes the voltage to limit. This voltage is influenced by the conditions in the combustion chamber (pressure, etc.).

A lot of work is going into finding other materials for use in engines. One such is the use of ceramics. Ceramics will stand far higher temperatures than any metal. In the early 1980s, Toyota researched production of an adiabatic ceramic engine which can run at a temperature of over 6000 °F (3300 °C). Ceramic engines do not require a cooling system and hence allow a major weight reduction and therefore greater fuel efficiency. Fuel efficiency of the engine is also higher at high temperature, as shown by Carnot's theorem. In a conventional metallic engine, much of the energy released from the fuel must be dissipated as waste heat in order to prevent a meltdown of the metallic parts. Despite all of these desirable properties, such engines are not in production because the manufacturing of ceramic parts in the requisite precision and durability is difficult. Imperfection in the ceramic leads to cracks, which can lead to potentially dangerous equipment failure. Such engines are possible in laboratory settings, but mass-production is unfeasible with current technology.

So keep thinking. You are on the right track.

Answer 4

The burning cycle of fuel has nothing to do with the tension of the spark.  The maximum amount of work than can be gotten out of fuel has to do with the temperature/pressure at peak and the temperature/pressure at minimum before exhaust.  The heat produced by the cycle not used for work has to be carried off, otherwise the engine gets hotter and hotter and becomes less efficient.  

  Also, fuel has to be injected (as in a diesel) at peak pressure because if it in the mix while compression is going on, it will explode early from remaining heat in the cylinder unless it is treated to be less flammable - higher octane - to prevent knocking..

Answer 5

" if the engine was made of phenolic"

I bet it would last less than 10 cycles before falling apart. Steel is really the best choice.

"could the spark voltage be higher"

Higher voltage spark would do nothing to get more power.

Compression is limited by preignition, which is why some engines require higher octane gas, they have a higher compression.