Fuel pump cut-off circuit
First Claim
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1. In an electronic fuel injection control system for an internal combustion engine having an electromagnetic fuel pump, a fuel pump relay, fuel metering means, a signal source of ignition pulses, and a supply voltage, a fuel pump cut-off circuit comprising:
- a first comparator means;
a second comparator means;
a first wave shaping/timing means coupling said signal source of ignition pulses to the non-inverting input of said first comparator means;
said first wave shaping/timing means for reshaping said ignition pulses in a predetermined way to create a newly shaped pulse train which is one half the frequency of the said signal source of ignition pulses;
a reference voltage means which presents a preselected reference voltage to the inverting input of said first comparator means and to the non-inverting input of said second comparator means;
a second wave shaping/timing means for reshaping the output of said first comparator means in a predetermined way such that said signal source of ignition pulses below a preselected reference frequency will not cause a change in the output state of said second comparator means;
said second comparator means which accepts at its inverting input the output of said first comparator means as reshaped by said second timing means and accepts at its non-inverting input said preselected reference voltage from said reference voltage means; and
fuel pump driver means connected to the output of said second comparator means and responding thereto for controlling the energization and deenergization of said fuel pump relay.
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Abstract
A circuit for automatically controlling an internal combustion engine'"'"'s electromagnetic fuel injection pump during the following three modes of operation: normal, low cranking and stall.
16 Citations
4 Claims
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1. In an electronic fuel injection control system for an internal combustion engine having an electromagnetic fuel pump, a fuel pump relay, fuel metering means, a signal source of ignition pulses, and a supply voltage, a fuel pump cut-off circuit comprising:
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a first comparator means; a second comparator means; a first wave shaping/timing means coupling said signal source of ignition pulses to the non-inverting input of said first comparator means; said first wave shaping/timing means for reshaping said ignition pulses in a predetermined way to create a newly shaped pulse train which is one half the frequency of the said signal source of ignition pulses; a reference voltage means which presents a preselected reference voltage to the inverting input of said first comparator means and to the non-inverting input of said second comparator means; a second wave shaping/timing means for reshaping the output of said first comparator means in a predetermined way such that said signal source of ignition pulses below a preselected reference frequency will not cause a change in the output state of said second comparator means; said second comparator means which accepts at its inverting input the output of said first comparator means as reshaped by said second timing means and accepts at its non-inverting input said preselected reference voltage from said reference voltage means; and fuel pump driver means connected to the output of said second comparator means and responding thereto for controlling the energization and deenergization of said fuel pump relay. - View Dependent Claims (2, 3, 4)
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Specification