Effect of Piston Speed around Top Dead Center on Thermal Efficiency

Accession number;06A0236528
Title;Effect of Piston Speed around Top Dead Center on Thermal Efficiency
Author; SUZUKI MASATOSHI (Honda R & D Co., Ltd.) IIJIMA SATOSHI (Honda R & D Co., Ltd.) KUBOTA RYO (Honda R & D Co., Ltd.) MAEHARA HAYATO (Honda R & D Co., Ltd.)
Journal Title;Honda R&D Tech Rev
Journal Code:L0353A
ISSN:0915-3918
VOL.18;NO.1;PAGE.101-106(2006)
Figure&Table&Reference;FIG.14, TBL.4, REF.10
Pub. Country;Japan
Language;Japanese
Abstract;In a reciprocating internal combustion engine, the Otto-cycle allows for maximum thermal efficiency with a same compression ratio, which means complete combustion in a moment at top dead center, which is practically impossible. In view of this fact, it can be considered that a slower transition of the piston speed near top dead center would promote combustion during that period. This, in turn, would increase the in-cylinder pressure and degree of constant volume thereby improving thermal efficiency. To prove this, an engine in which the piston can be displaced moderately to achieve ideal constant volume combustion was prepared and experiments were carried out. As anticipated, while the degree of constant volume increased, the thermal efficiency did not improve due to increased heat loss. Subsequently, further experiments were carried out using a direct injection, stratified charge engine which allows selective reduction of heat loss, and a high thermal efficiency was attained. (author abst.)