Knock in spark-ignition engines : End-gas temperature measurements using rotational CARS and detailed kinetic calculations of the autoignition process
Author
Summary, in English
Cycle-resolved end-gas temperatures were measured using dual-broadband rotational CARS in a single-cylinder spark-ignition engine. Simultaneous cylinder pressure measurements were used as an indicator for knock and as input data to numerical calculations. The chemical processes in the end-gas have been analysed with a detailed kinetic mechanism for mixtures of iso-octane and n-heptane at different Research Octane Numbers (RON'S). The end-gas is modelled as a homogeneous reactor that is compressed or expanded by the piston movement and the flame propagation in the cylinder. The calculated temperatures are in agreement with the temperatures evaluated from CARS measurements. It is found that calculations with different RON'S of the fuel lead to different levels of radical concentrations in the end-gas. The apperance of the first stage of the autoignition process is marginally influenced by the RON, while the ignition delay of the second stage is increased with increasing RON.
Department/s
Publishing year
1997
Language
English
Publication/Series
SAE Technical Papers
Document type
Conference paper
Conference name
International Spring Fuels and Lubricants Meeting
Conference date
1997-05-05 - 1997-05-08
Conference place
Dearborn, MI, United States
Status
Published