Browse Publications Technical Papers 2008-01-1652

A Study of Crevice HC Mechanism Based on the Transient HC Test Data and the Double Zone Combustion Model 2008-01-1652

The effectiveness of after-treatment systems depends on the exhaust gas temperature, which is low during cold-start. As a result, Euro III, Euro IV and FTP75 require that the emissions tests include exhaust from the beginning of cold start. It is proved that 50%∼80% of HC and CO emissions are emitted during the cold start and the amount of unburned fuel from the crevices during starting is much higher than that under warmed engine conditions. The piston crevices is the most part of combustion chamber crevices, and results of mathematical simulations show that the piston crevice contribution to HC emissions is expected to increase during cold engine operation.
Based on the transient HC test data and the double zone combustion model, this paper presents the study of the crevice HC Mechanism of the first firing cycle at cold start on an LPG SI Engine. A fast-response flame ionization detector (FFID) was employed to measure transient HC emissions of the first firing cycle. At the same time, the transient cylinder pressure and instantaneous crankshaft speed of the engine were measured and recorded. Based on the transient HC test data and the double zone combustion model, the crevice HC mechanism model was set up. The cylinder pressure of the combustion simulation has a good relation with the test data, and the crevice HC model is proved by the comparison between the simulation and the test results. By the simulation, it is found that the HC mole concentration in the crevice at the peak cylinder pressure time has a great effect on the HC emissions for the first firing cycle.


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:

Cold Start HC Reduction with Feedback Control Using a Crank Angle Sensor


View Details


Adsorption-based Structural Characterization of Intake Valve Deposits


View Details


Diagnostics for the Study of Cold Start Mixture Preparation in a Port Fuel-Injected Engine


View Details