Closed loop programmable EGR with coolant temperature sensitivity
First Claim
1. An EGR system for an internal combustion engine comprising:
- an electronic processor means for generating a desired EGR value as a function of the operating parameters of the internal combustion engine;
a sensor means for generating an actual EGR value by sensing the actual flow of exhaust gas through a recirculation loop;
a variable EGR valve means disposed in said recirculation loop, said valve means operable to vary the amount of exhaust gas passing through said recirculation loop;
control means for comparing said desired EGR value to said actual EGR value, said control means generating an increase signal when said actual EGR value is less than said desired EGR value as a result of the comparison and generating a decrease signal when said actual EGR value is greater than said desired EGR value as a result of said comparison, the control means further regulating the EGR valve in response to the increase and decrease signals to descrease EGR flow at a controllable rate in the event of a decrease signal and to increase EGR flow at a controllable rate in the event of an increase signal.
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Accused Products
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.
54 Citations
13 Claims
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1. An EGR system for an internal combustion engine comprising:
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an electronic processor means for generating a desired EGR value as a function of the operating parameters of the internal combustion engine; a sensor means for generating an actual EGR value by sensing the actual flow of exhaust gas through a recirculation loop; a variable EGR valve means disposed in said recirculation loop, said valve means operable to vary the amount of exhaust gas passing through said recirculation loop; control means for comparing said desired EGR value to said actual EGR value, said control means generating an increase signal when said actual EGR value is less than said desired EGR value as a result of the comparison and generating a decrease signal when said actual EGR value is greater than said desired EGR value as a result of said comparison, the control means further regulating the EGR valve in response to the increase and decrease signals to descrease EGR flow at a controllable rate in the event of a decrease signal and to increase EGR flow at a controllable rate in the event of an increase signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification