Browse Publications Technical Papers 2004-01-1262

A New Analysis Method for Accurate Accounting of IC Engine Pumping Work and Indicated Work 2004-01-1262

In order to improve fuel economy, engine manufacturers are investigating various technologies that reduce pumping work in spark ignition engines. Current cylinder pressure analysis methods do not allow valid comparison of pumping work reduction strategies. Existing methods neglect valve timing effects which occur during the expansion and compression strokes, but are actually part of the gas exchange process. These additional pumping work contributions become more significant when evaluating non-standard valve timing concepts.
This paper outlines a new analysis method for calculating the pumping work and indicated work of a 4-stroke internal combustion engine. Corrections to PMEP and IMEP are introduced which allow the valid comparison of pumping work and indicated efficiency between engines with different pumping work reduction strategies. Several example data sets are presented which illustrate the method and the necessity for the corrections when analyzing engines with non-standard valve timings.
The upper limit potential improvement in BSFC available from PMEP reduction is presented and compared to the actual benefit obtained with three pumping work reduction strategies: 1) variable valve timing, 2) intake charge dilution (stratified lean operation) and 3) cylinder deactivation.


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


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:

Effects of Intake Valve Closing Timing on Gasoline Engine Performance and Emissions


View Details


A New Approach for Optimization of Mixture Formation on Gasoline DI Engines


View Details


Strategies for Improving Fuel Consumption at Part-Load in a Downsized Turbocharged SI Engine: a Comparative Study


View Details