1977-02-01

Compression Ratio Effects With Lean Mixtures 770640

To investigate the fuel-economy benefits of increased compression ratio in modern emission-controlled engines, the compression ratios of two car makes were increased one unit while holding emission levels and performance nearly constant. All cars were modified for lean-burn operation by using the Turbulent Flow Manifold, a carburetor adjusted for lean air-fuel mixtures, and special calibration of ignition timing and exhaust gas recycle rate. Exhaust port liners and a deceleration valve were used to control the tendency for HC emissions to increase at higher compression ratios.
In addition, thermal reactors were installed on one high-compression car. The increased efficiency of this aftertreatment device allowed a simultaneous improvement in fuel economy and decrease in hydrocarbon emissions. Based on fuel economy gains and refining savings, this car offers an 8.2% fuel savings over its 1977 certification counterpart.

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

Effects of Compression Ratio on Spark-Ignited Engine Efficiency

2014-01-2599

View Details

TECHNICAL PAPER

Effects of Stratified EGR on the Performance of a Liquid Phase LPG Injection Engine

2004-01-0982

View Details

TECHNICAL PAPER

A Study on the Idle Combustion Stability of a CNG Powered Naturally Aspirated Engine

2013-26-0003

View Details

X