# US 5,701,870 A · Programmable fuel injector current waveform control and method of operating same

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- Number: US 5,701,870 A
- Document ID: US5701870A
- Status: Granted
- Kind: A
- Application number: 08/632,046
- Filed: 1996-04-15
- Granted: 1997-12-30
- Earliest claimed: 1996-04-15
- Assignees: Caterpillar Inc.
- Inventors: Paul C. Gottshall; Paul M. Young
- Web page: https://patentgrep.com/patent/US5701870A

## CPC

- F02D 41/20: Output circuits, e.g. for controlling currents in command coils
- F02D 2041/2017: {using means for creating a boost current or using reference switching}
- F02D 2041/2058: {using information of the actual current value}
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)

## Abstract

A fuel injector control circuit is disclosed. The circuits can be used with a plurality of different fuel injectors and can be programmed to produce a plurality of different injector current waveforms. The control preferably includes a microprocessor with memory connected to a multiplexer and an application specific integrated circuit. The control can also be used to increase the current rise time of a specific injector current waveform.

## Claims

### Claim 1

An apparatus for variably controlling an injection current waveform to a fuel injector on a compression ignition engine, said apparatus comprising:
an electronic controller, said electronic controller producing at least one desired current waveform parameter and a control signal;
a memory device associated with said electronic controller;
a control circuit connected to said electronic controller and receiving said desired current waveform parameter and said control signal;
wherein said control circuit is capable of producing a plurality of injection current waveforms corresponding to a plurality of fuel injectors and control circuit produces one of said plurality of injection current waveforms responsive to said desired current waveform parameter and said control signal;
a first desired current waveform parameter;
a second desired current waveform parameter;
a multiplexer receiving said first and second desired current waveform parameters;
an application specific integrated circuit (injector controller) receiving said control signal and producing a mulitplexer control signal;
said control circuit receiving a current feedback signal corresponding to current flowing through a fuel injector; and
said injector controller producing a multiplexer control signal causing said multiplexer to output said second desired current waveform parameter in response to said current feedback signal indicating a current corresponding to said first desired current waveform parameter.

### Claim 2 (depends on 1)

An apparatus according to claim 1, wherein said injector controller produces fuel injector select signal to cause a desired current waveform to be applied to one of a plurality of fuel injectors.