1973-02-01

Exhaust Emission Characteristics of a Small 2-Stroke Cycle Spark Ignition Engine 730159

The 2-stroke cycle engine has not been subject to extensive exhaust emission research because small vehicles which commonly employ 2-stroke cycle engines are not covered by federal emission regulations. This paper reports the results of a 2-stroke engine study conducted to determine the level of the unburned hydrocarbon (HC) emission and its source. Other gas phase exhaust emissions are reported as well.
Exhaust composition curves were generated from a material balance model with HCs included as a product. The calculated curves were used in the analysis of the experimental data. It was determined that 25-40% of the fuel air mixture was short-circuited to the exhaust in the scavenging process which resulted in unburned HC concentrations of 5000-1000 ppm hexane equivalent. It was found that short-circuiting is a function of load but is relatively independent of speed. Emission of carbon monoxide is highly dependent on carburetor tuning and can be reduced to less than 1% vol by tuning alone. Nitric oxide emission is low compared to uncontrolled 4-stroke engines; mass emission is less than 5 g/bhp·h at most operating conditions.

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 Sampling System for the Measurement of PreCatalyst Emissions from Vehicles Operating Under Transient Conditions

930141

View Details

TECHNICAL PAPER

Can the Technology for Heavy Duty Diesel Engines be Common for Future Emission Regulations in USA, Japan and Europe?

2003-01-0344

View Details

TECHNICAL PAPER

Reduction of Exhaust Gas Emissions by Using Hydrocarbon Adsorber Systems

930738

View Details

X