Autori: CLENCI A., IVAN Fl., RACOTA R.

Editorial: Proceedings of the International ESFA Automotive Congress, Bucuresti, organized under the great patronage of FISITA, 2003.

Rezumat:

Since the knock and NOx is affected by the gas temperature and pressure at TDC, in other words by the geometrical compression ratio, while the thermal efficiency of the cycle is determined by the work during the expansion stroke, a better way to increase the efficiency is to have higher expansion ratios rather than higher compression ratios.
Thus the paper presents some results regarding the effect of high compression and high expansion theoretical cycle in a spark ignition engine, the latter being obtained by means of late closing of the intake valve(s)

Cuvinte cheie: compression ratio vs. expansion ratio