Title: Closed loop programmable EGR with coolant temperature sensitivity

Abstract: A closed loop programmable EGR control system is disclosed. The EGR control system comprises a first read only memory having a look up table of base EGR pulse widths as a function of engine speed and absolute manifold pressure. This base EGR pulse width is corrected to a total desired pulse width by adding a correction pulse width obtained from a second read only memory. The second ROM stores values of the correction pulse width in a look up table as a function of engine speed and engine coolant temperature. This desired value of EGR pulse width is then compared to the actual EGR flow as sensed directly by a differential pressure transducer located in the exhaust gas recirculation conduit and an error signal is generated therefrom. The error signal is subsequently used to operate a solenoid pilot valve that alternately applies either a vacuum or atmospheric vent at a controllable rate to an EGR valve regulating the amount of exhaust gas recirculated to thereby reduce the error between the actual and desired EGR values.

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Inventors: Toelle, Alvin D. (Fenton, MI, US)

Application Number: 870966
Filing Date: 1978-01-19
Publication_date: 1979-08-14
Assignee: The Bendix Corporation (Southfield, MI)
Primary Class(es): 123/568.27 701/108
Other Classes:
US Patent Ref:

3799133	Mar, 1974	Frank	123/119.
3872846	Mar, 1975	Taplin et al.	123/119.
3915134	Oct, 1975	Young et al.	123/119.
3963011	Jun, 1976	Saito et al.	123/119.
3969614	Jul, 1976	Moyer et al.	123/119.
3982395	Sep, 1976	Hasegawa et al.	123/119.
4024847	May, 1977	Koganemaru	123/119.
4044738	Aug, 1977	Williams et al.	123/119.
4052968	Oct, 1977	Hattori et al.	123/119.
4071003	Jan, 1978	Aono	123/119.

Other Refs:
Primary Examiner: Burns, Wendell E.
Assistant Examiner:
Attorney: Marvin; William A.