Lift pump control for a two pump direct injection fuel system
First Claim
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1. A method to operate a lower pressure pump operating as part of a direct injection fuel system, the method comprising:
- operating a lower pressure pump in a first mode during a first operating condition of an internal combustion engine, said lower pressure pump supplying fuel to a higher pressure pump that supplies fuel to fuel injectors that directly inject fuel to a cylinder, said first mode comprising adjusting energy supplied to said lower pressure pump as output from a sensor located downstream of said higher pressure pump varies while said higher pressure pump is substantially deactivated;
operating said lower pressure pump in a second mode during a second operating condition of said internal combustion engine, said second mode comprising varying energy supplied to said lower pressure pump as operating conditions of said internal combustion engine vary while said higher pressure pump is activated; and
applying an energy command learned while in said first mode to the lower pressure pump in said second mode.
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Abstract
An economical method for controlling a lift pump operating as part of a direct injection fuel system is described. According to the method, at least two distinct operating modes are provided.
43 Citations
20 Claims
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1. A method to operate a lower pressure pump operating as part of a direct injection fuel system, the method comprising:
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operating a lower pressure pump in a first mode during a first operating condition of an internal combustion engine, said lower pressure pump supplying fuel to a higher pressure pump that supplies fuel to fuel injectors that directly inject fuel to a cylinder, said first mode comprising adjusting energy supplied to said lower pressure pump as output from a sensor located downstream of said higher pressure pump varies while said higher pressure pump is substantially deactivated; operating said lower pressure pump in a second mode during a second operating condition of said internal combustion engine, said second mode comprising varying energy supplied to said lower pressure pump as operating conditions of said internal combustion engine vary while said higher pressure pump is activated; and applying an energy command learned while in said first mode to the lower pressure pump in said second mode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method to operate a lift pump operating as part of a direct injection fuel system, the method comprising:
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operating a lift pump in a first mode during a first operating condition of an internal combustion engine, said lift pump supplying fuel to an injection pump that supplies fuel to fuel injectors that directly inject fuel to a cylinder, said first mode comprising adjusting energy supplied to said lift pump as output from a sensor located downstream of said injection pump varies while said injection pump is deactivated; storing a lift pump variable that corresponds to a pressure observed at said sensor as said engine operates in the first mode; and operating said lift pump in a second mode and adjusting an outlet pressure of said lift pump with said lift pump variable. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method to operate lift and injection pumps that are part of a direct injection fuel system, the method comprising:
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operating a lift pump in a first mode during a first operating condition of an internal combustion engine, said lift pump supplying fuel to an injection pump that supplies fuel to fuel injectors that directly inject fuel to a cylinder, said first mode comprising adjusting energy supplied to said lift pump as output from a sensor located downstream of said injection pump varies while said injection pump is deactivated; operating said lift pump in a second mode during a second operating condition of said internal combustion engine, said second mode comprising varying energy supplied to said lift pump as operating conditions of said internal combustion engine vary while said injection pump is activated; and predicting fuel rail pressure during reactivation of said injection pump by counting a number of fuel pump strokes after reactivating said injection pump. - View Dependent Claims (18, 19, 20)
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Specification