US 4,338,651 A · Dual coil driver

Abstract

A driver circuit, having boost and hold modes of operation, for a solenoid having a high and a low impedance coil wherein the coils are so situated such that their respective magnetic fields are additive and wherein the driver circuit is responsive to input metering pulse width signals and includes means for modifying the duration of each pulse width signal to generate a boost pulse signal to excite the low impedance coil in correspondence with the variations in the battery voltage. The driver circuit further includes means for permitting the current flowing through the low impedance coil into flow into a high impedance coil and means for regulating the value of current flowing therethrough at a determinable value. The driver circuit further includes means for reducing the current droop occurring upon the transition from the boost mode of operation to the hold mode of operation.

Claims22

Dependent claims

A driver circuit for a fuel injector, the driver circuit adapted to be connected to a voltage source and to receive input metering signals from an electronic control unit, for controlling the operation of a solenoid of the type having a plurality of coils situated so as to produce, when activated, aiding magnetic fields, the driver circuit comprising:

voltage regulator means connected to said voltage source for generating a regulated voltage;
adaptive means, responsive to the metering signals for generating a pulse width boost signal that is variable in correspondence with fluctuations of the voltage level of said voltage source;
first driver means, responsive to said boost signal, and connected to the first of said coils for causing current to flow therethrough;
second driver means, responsive to said boost signal, and connected to the second of said coils for activating said second coil and for causing the current flowing through said first coil to flow through said second coil;
and
first means connected to said first or said second driver means for reducing current droop upon activation of said second coil.

3 more elements

A driver system responsive to metering pulses for fuel injectors comprising:

a voltage source (90);
voltage regulator means (42) connected to said voltage source for generating a regulated voltage;
a boost coil (22) having one terminal connected to said voltage source and a second terminal;
a hold coil (24) having one terminal connected to the second terminal of said boost coil and having a second terminal;
an isolation diode (60) connected between the second terminal of said boost coil and the first terminal of said hold coil,
a sense resistor;
hold coil driver means, including a first Darlington pair (154) having its output or collector terminal connected to the second terminal of said hold coil and having its emitter terminal connected to ground through said sense resistor and further having an input or base terminal;
regulator means (70, 156) for regulating the level of current flowing through said sense resistor comprising:
a feedback voltage regulator (224) responsive to the voltage across said sense resistor and having an output connected to the base terminal of said hold coil driver means;
a first NPN transistor (222), adapted to receive the metering pulse at its base terminal, and having its collector connected to the base of said first Darlington pair and further having its emitter terminal grounded;
first means (232) connected between the second terminal of said second coil and said feedback voltage regulator for reducing current droop upon the activation of said second coil;
adaptive means (40, 210, 202) responsive to the metering signals for generating a boost signal having a pulse width that is variable in correspondence width the fluctuations of the voltage level of said voltage source;
and
boost coil driver means (44) responsive to the output of said adaptive means and the metering pulse for causing current to flow through said boost coil.

11 more elements

Dependencies are inferred from the claim text.

Dual coil driver

Life of this patent

Dual coil driver

Life of this patent

Abstract

Claims22