Reducing cold start hydrocarbon emissions from port fuel injected spark ignition engines with improved management of hardware & controls

An experimental study was performed to investigate strategies for reducing cold start hydrocarbon (HC) emissions from port fuel injected (PFI) spark ignition (SI) engines with better use of existing hardware and control systems. Engine experiments and computer simulations were used for three major phases of the project: the effect of variable valve timing on first cycle mixture preparation, the interaction between fuel injection and valve events, and the development of a flow reactor exhaust manifold for fast catalyst light-off. For the first cycle of cranking, delaying the intake valve opening (IVO) creates a pressure difference across the valve, resulting in strong but brief shear flow to facilitate atomization; delayed IVO also produces a cooler charge due to the expansion process before IVO. It was observed that the in-cylinder equivalence ratio increased with delayed IVO, primarily by displacing the lean portion of the stratified cylinder charge back into the port. However, HC emissions for the first cranking cycle increased with delayed IVO. With closed valve injection, injection timing has no significant impact on mixture preparation or emissions. With open valve injection, however, HC emissions scale with both valve lift and mass flow because of increased cylinder wall wetting.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Lang, Kevin R., 1980-

Advisor dc:contributor.advisor

• Wai K. Cheng.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/36191

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/36191