1989-08-01

The Effect of Piston Motion on Time Loss in a Spark Ignition Engine 891675

Combustion of a spark ignition engine is often idealized by a constant volume process. However, due to piston motion, constant volume combustion can not be realized in an actual engine cycle, and this leads to a loss in thermal efficiency when compared to an ideal Otto cycle. In this paper, such a loss associated with piston motion, termed as time loss, is rigorously studied for spark ignition engines of different piston motion mechanisms. It is found that the time loss of a conventional slider crank engine amounts to maximum 9 % of the total loss depending upon operating conditions. Especially, in the limit of long crankshaft, where piston motion follows a perfect sinusoid, it is shown that the time loss decreases by 2 - 5 %. To determine the dominant factors affecting the time loss, also investigated are the effects of major performance parameters such as compression ratio, combustion start and duration.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:
TECHNICAL PAPER

A Small DI Ceramic Engine

860442

View Details

TECHNICAL PAPER

Analysis of an Extended Stroke, (Offset Crankshaft), Engine

2006-01-0014

View Details

TECHNICAL PAPER

Offset Crankshaft Effects on SI Engine Combustion and Friction Performance

2004-01-0606

View Details

X