Reduction of Octane Requirement by Knock Sensor Spark Retard System Exxon Research and Engineering Company

Format:

Conference/Event

Author/Creator:

Kraus, B.J., author.

Conference Name:

1978 Automotive Engineering Congress and Exposition (1978-02-27 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 1978

Summary:

A 1975 California model automobile with an 8:1 C.R. 350 CID engine was modified by increasing the compression ratio to 9:1 which resulted in improved fuel economy. The higher NOx emissions were reduced to the base level by substituting a back pressure-controlled EGR unit for the original valve and increasing the EGR flow. Octane requirement was controlled by a knock sensor-actuated spark timing retard system. The knock sensor (accelerometer) is attached to one of the cylinder heads of the engine. When knock occurs, the vibration is picked up by the sensor, the signal is filtered to remove some of the engine background noise, and the knock pulse is detected. When the amplitude of the detected knock signal exceeds a threshold, the spark timing is retarded. When no knocking is detected over a waiting period, the timing is advanced back to its normal schedule. Using this system, the vehicle's octane requirement can be lowered several numbers with some performance debit, id est, slower acceleration times

Notes:

Vendor supplied data

Publisher Number:

780155

Access Restriction:

Restricted for use by site license