GB2023722A

GB2023722A - Ignition timing device for an internal combustion engine

Info

Publication number: GB2023722A
Application number: GB7909166A
Authority: GB
Original assignee: Kloeckner Humboldt Deutz AG
Current assignee: Kloeckner Humboldt Deutz AG
Priority date: 1978-03-25
Filing date: 1979-03-15
Publication date: 1980-01-03
Also published as: GB2023722B; FR2420667A1; IT7920726A0; DE2813190A1; JPS54126834A; IT1111131B

Abstract

The device for controlling the ignition point of an internal combustion engine comprises an electronic control 17 which is responsive to a pick-up 18 at the fuel injection valve 12 detecting one or more parameters of the fuel injection system, e.g. the beginning of the pressure rise at the injector valve nozzle; a predetermined pressure gradient; valve opening pressure; pressure irruption or collapse after opening pressure is reached; time integral at nozzle pressure; and/or lift of needle valve. <IMAGE>

Description

SPECIFICATION Ignition timing device for an internal combustion engine This invention relates to a device for controlling the ignition point of an externally-ignited internal combustion engine with fuel injection.

In known devices of this kind, the ignition timing is controlled in dependence on load and speed by a mechanically driven contact breaker. Devices of this kind, however, do not allow for the change, depending on load and speed, in the commencement of injection which is a peculiar requirement of the injection system used. Admittedly the commencement of injection can be varied to suit a particular system, but if it is optimized with respect to a given ignition point, important parameters of the ignition system will be fixed and it will thus be different or impossible to design it in accordance with other requirements.

In known internal combustion engines, injection, mixture formation and ignition occur within a short space of time near the top dead centre position of the piston. If independent adjustments are made in the ignition point, using conventional centrifugally-controlleld mechanical contact breakers in conjunction with hydraulically-produced changes in the commencement of injection, the fuel to be injected, at the time of injection, will be in a phase of jet formation or mixture formation which varies with the operating state of the internal combustion engine. The known devices can provide optimum mixture formation only at one operating point.

The object of the invention is to provide a device for controlling the ignition point whereby allowance is made for the hydraulic influences of the injection system.

To this end, according to the invention, there is provided a device for controlling the ignition point of an externally-ignited internal combustion engine comprising an electronic control for the ingition system which is responsive to one or more parameters of the fuel injection system.

In the device according to the invention, the ignition time can be varied to suit the fuel injection so that the fuel is in an optimum state of preparation when ignition takes place.

A device according to the invention can be manufactured, using simple means, by disposing a pick-up at the injector valve which supplies a corresponding control unit of the ignition system with a trigger signal, i.e., a particular value of a hydraulic parameter such as the beginning of the pressure rise at the nozzle end of the injector valve; the instant when a given pressure gradient is reached; the opening pressure of the fuel injector valve; the pressure irruption (or collapse) after the openint pressure has been reached; the integral of the nozzle pressure with respect to time; and/or the instant when the injector needle begins to lift. The trigger signal is processed in accordance with a predetermined program, allowing for additional parameters if required, and thus establishes the correct ignition point.

An embodiment of the invention is shown in the accompanying drawing, which is a partial cross-section of an internal combustion engine comprising a device according to the invention.

The internal combustion engine comprises a crankcase 1 supporting an air-cooled cylinder 2 closed by a cylinder head 3 and containing a piston 4 formed with a combustion chamber cavity 5, which piston moves in its axial direction. A connecting rod 7 is pivoted via a gudgeon pin 6 to piston 4. Cylinder head 3 has actuating elements 8 for gas-change valves 9. The suction and exhaust lines are denoted by 10 and 11.

A fuel injection pump 1 3 injects fuel through an injector valve 1 2 into the combustion chamber cavity 5 of piston 4. An ignition device comprising a spark plug 14, a current source 15, an ignition coil 16, a control unit 1 7 and a pick-up 18, ignites the injected fuel.

Pick-up 1 8 is disposed at the fuel injector valve 1 2 and determines the ignition point, by supplying the control unit 1 7 with a trigger signal, i.e., a given value of a hydraulic parameter, such as the beginning of the pressure increase at the injector nozzle end; the time when a given pressure gradient is reached; or the opening pressure of the fuel injection valve. The control unit 1 7 processes the trigger signal in accordance with a given program, allowing for additional parameters if required, and so establishes the correct ignition point.

1. A device for controlling the ignition point of an externally-ignited internal combustion engine, comprising an electronic control for the ignition system which is responsive to one or more hydraulic parameters of the fuel injection system.

2. A device according to claim 1, comprising a pick-up disposed at a fuel injection valve to provide a trigger signal, i.e., a particular value of a hydraulic parameter, and means to process the trigger signal in accordance with a predetermined programme, allowing for other parameters if required, in order to establish the correct ignition point.

3. A device according to claim 1 or claim 2, in which the trigger signal used is the beginning of the pressure rise at the injector nozzle end; the instant when a given pressure gradient is reached; the opening pressure of the fuel injection valve; the pressure irruption (or collapse) after the opening pressure has been reached; a given value of the integral of

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Ignition timing device for an internal combustion engine This invention relates to a device for controlling the ignition point of an externally-ignited internal combustion engine with fuel injection. In known devices of this kind, the ignition timing is controlled in dependence on load and speed by a mechanically driven contact breaker. Devices of this kind, however, do not allow for the change, depending on load and speed, in the commencement of injection which is a peculiar requirement of the injection system used. Admittedly the commencement of injection can be varied to suit a particular system, but if it is optimized with respect to a given ignition point, important parameters of the ignition system will be fixed and it will thus be different or impossible to design it in accordance with other requirements. In known internal combustion engines, injection, mixture formation and ignition occur within a short space of time near the top dead centre position of the piston. If independent adjustments are made in the ignition point, using conventional centrifugally-controlleld mechanical contact breakers in conjunction with hydraulically-produced changes in the commencement of injection, the fuel to be injected, at the time of injection, will be in a phase of jet formation or mixture formation which varies with the operating state of the internal combustion engine. The known devices can provide optimum mixture formation only at one operating point. The object of the invention is to provide a device for controlling the ignition point whereby allowance is made for the hydraulic influences of the injection system. To this end, according to the invention, there is provided a device for controlling the ignition point of an externally-ignited internal combustion engine comprising an electronic control for the ingition system which is responsive to one or more parameters of the fuel injection system. In the device according to the invention, the ignition time can be varied to suit the fuel injection so that the fuel is in an optimum state of preparation when ignition takes place. A device according to the invention can be manufactured, using simple means, by disposing a pick-up at the injector valve which supplies a corresponding control unit of the ignition system with a trigger signal, i.e., a particular value of a hydraulic parameter such as the beginning of the pressure rise at the nozzle end of the injector valve; the instant when a given pressure gradient is reached; the opening pressure of the fuel injector valve; the pressure irruption (or collapse) after the openint pressure has been reached; the integral of the nozzle pressure with respect to time; and/or the instant when the injector needle begins to lift. The trigger signal is processed in accordance with a predetermined program, allowing for additional parameters if required, and thus establishes the correct ignition point. An embodiment of the invention is shown in the accompanying drawing, which is a partial cross-section of an internal combustion engine comprising a device according to the invention. The internal combustion engine comprises a crankcase 1 supporting an air-cooled cylinder 2 closed by a cylinder head 3 and containing a piston 4 formed with a combustion chamber cavity 5, which piston moves in its axial direction. A connecting rod 7 is pivoted via a gudgeon pin 6 to piston 4. Cylinder head 3 has actuating elements 8 for gas-change valves 9. The suction and exhaust lines are denoted by 10 and 11. A fuel injection pump 1 3 injects fuel through an injector valve 1 2 into the combustion chamber cavity 5 of piston 4. An ignition device comprising a spark plug 14, a current source 15, an ignition coil 16, a control unit 1 7 and a pick-up 18, ignites the injected fuel. Pick-up 1 8 is disposed at the fuel injector valve 1 2 and determines the ignition point, by supplying the control unit 1 7 with a trigger signal, i.e., a given value of a hydraulic parameter, such as the beginning of the pressure increase at the injector nozzle end; the time when a given pressure gradient is reached; or the opening pressure of the fuel injection valve. The control unit 1 7 processes the trigger signal in accordance with a given program, allowing for additional parameters if required, and so establishes the correct ignition point. CLAIMS

3. A device according to claim 1 or claim 2, in which the trigger signal used is the beginning of the pressure rise at the injector nozzle end; the instant when a given pressure gradient is reached; the opening pressure of the fuel injection valve; the pressure irruption (or collapse) after the opening pressure has been reached; a given value of the integral of the nozzle pressure with respect to time; and/ or the time when the injector needle begins to lift.

4. A device for controlling the ignition point of an externally-ignited internal combustion engine, constructed and arranged substantially as herein described, with reference to and as illustrated in the accompanying drawing.