# US 6,293,255 B1 · Fuel injection system

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- Number: US 6,293,255 B1
- Document ID: US6293255B1
- Status: Granted
- Kind: B1
- Application number: 09/569,390
- Filed: 2000-05-12
- Granted: 2001-09-25
- Earliest claimed: 1997-01-31
- Assignees: Yamaha Hatsudoki Kabushiki Kaisha
- Inventors: Kimitake Otome; Junichi Kaku; Hidetoshi Kageyama
- Web page: https://patentgrep.com/patent/US6293255B1

## CPC

- F02M 63/06: Use of pressure wave generated by fuel inertia to open injection valves
- F02B 61/02: for driving cycles
- F02D 37/02: one of the functions being ignition
- F02D 41/2096: {for controlling piezoelectric injectors (drive and control circuit for piezoelectric devices in general H10N30/802)}
- F02M 51/0603: {using piezoelectric or magnetostrictive operating means}
- F02M 57/027: {electric}
- F02D 2041/2034: {Control of the current gradient}
- F02D 2041/2051: {using voltage control}
- F02M 2200/21: Fuel-injection apparatus with piezoelectric or magnetostrictive elements
- F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- 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

The present invention is an injection system including an injection device. The injection device includes a pumping chamber and an electrically operated device associated with the pumping chamber which, when energized, is capable of providing a rapid increase in localized fluid pressure in said pumping chamber without reciprocating a piston in a cylinder bore. A discharge port associated with the pumping chamber permits discharging of fluid displaced by the localized pressure increase. The injection system includes a circuit providing an energizing voltage to the electrically operated device, and a control for changing at least one characteristic of the energizing voltage selected from the group consisting of: the peak energizing voltage, the rate at which said energizing voltage increases, the rate at which said energizing voltage decreases, the duration of energization, and the frequency of energization.

## Claims

### Claim 1

A fuel injection device for a fuel system of an engine for delivering fuel to a fuel injector valve of said engine, said injection device including an electrostrictive element driven fluid pumping device comprising a pumping chamber, a piezoelectric element disposed within said pumping chamber and forming the sole means within said pumping chamber for increasing the pressure therein, said pumping chamber having a continuously open outlet through which pressurized fluid is discharged to said fuel injector valve, said piezoelectric element being selectively energized by a voltage supplied by an electric circuit which is switchable between a powered condition and a discharged condition, wherein the total volume of fuel injected in a single injection cycle through said outlet is controlled by changing a peak voltage or the rate of increase or decrease in voltage applied to said piezoelectric element by said circuit.

### Claim 2 (depends on 1)

The fuel injection device in accordance with claim 1, wherein said volume of fuel injected in a single injection cycle is large when a load upon said engine is large, as compared to when the load upon said engine is small.

### Claim 3 (depends on 1)

The fuel injection device in accordance with claim 1, wherein said volume of fuel injected in a single injection cycle is increased as a load on said engine increases.

### Claim 4 (depends on 1)

The fuel injection device in accordance with claim 1, wherein said volume of fuel injected in a single injection cycle is decreased as a load on said engine decreases.