With direct fuel injection and a sump-based lubrication system, a two-stroke engine produces air pollution no worse than a four-stroke, and it can achieve higher thermodynamic efficiency.
32.
For the 15 litre diesel example, the acoustic power generated from engine surfaces is of the order of a few tens of watts at most and is always ignored in engine thermodynamic efficiency calculations.
33.
However, one key advantage of pyroelectrics over thermoelectrics is that many pyroelectric materials are stable up to 1200 p C or higher, enabling energy harvesting from high temperature sources and thus increasing thermodynamic efficiency.
34.
The lowering of ambient pressure however, lowers the thermodynamic efficiency of combustion ( think of it the other way around where the higher the compression ratio in an infernal combustion engine, the higher the efficiency ).
35.
Electric motors are better still, at around 85-90 % efficiency or more, but they rely on an external power source ( often another heat engine at a power plant subject to similar thermodynamic efficiency limits ).
36.
Some advanced reactor designs being studied, such as the very high temperature reactor, advanced gas-cooled reactor and supercritical water reactor, would operate at temperatures and pressures similar to current coal plants, producing comparable thermodynamic efficiency.
37.
The Chevrolet Volt is expected to achieve 50 MPGe when running on the auxiliary power unit ( a small onboard generator ) at 33 % thermodynamic efficiency that would mean 12 kWh for, or about 240 watt-hours per mile.
38.
:I also, now that I think about it, have an engineering textbook that gives data on the thermodynamic efficiency of animals ( ie calorific value of food eaten vs mechanical power output )-I will post again later.
39.
:" Although theoretical calculations can be made today, the eventually attainable range of chemical reaction cycles, error rates, speed of operation, and thermodynamic efficiencies of such bottom-up manufacturing systems cannot be reliably predicted at this time.
40.
The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency from the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible expansion process.
