Effect of Exhaust Valve Timing on Gasoline Engine Performance and Hydrocarbon Emissions University of Michigan

Format:

Book

Conference/Event

Author/Creator:

Bohac, Stanislav V., author.

Conference Name:

2004 Powertrain & Fluid Systems Conference & Exhibition (2004-10-25 : Tampa, Florida, United States)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2004

Summary:

Despite remarkable progress made over the past 30 years, automobiles continue to be a major source of hydrocarbon emissions. The objective of this study is to evaluate whether variable exhaust valve opening (EVO) and exhaust valve closing (EVC) can be used to reduce hydrocarbon emissions. An automotive gasoline engine was tested with different EVO and EVC timings under steady-state and start-up conditions.The first strategy that was evaluated uses early EVO with standard EVC. Although exhaust gas temperature is increased and catalyst light-off time is reduced, the rapid drop in cylinder temperature increases cylinder-out hydrocarbons to such a degree that a net increase in hydrocarbon emissions results. The second strategy that was evaluated uses early EVO with early EVC. Early EVO reduces catalyst light-off time by increasing exhaust gas temperature and early EVC keeps the hydrocarbon-rich exhaust gas from the piston crevice from leaving the cylinder. The net result is that start-up hydrocarbon emissions are reduced by 27%

Notes:

Vendor supplied data

Publisher Number:

2004-01-3058

Access Restriction:

Restricted for use by site license