FUEL INJECTION SYSTEMS FOR INTERNAL COMBUSTION ENGINES
First Claim
1. A fuel injection system for an internal combustion engine, comprising at least two electromagnetically operable fuel injection valve and a pulse generator for intermittently energizing each valve in timed relation to the engine-operaTing cycle, wherein there is provided an overrun control circuit comprising means responsive to an engine-operating parameter indicative of an engine-overrun condition and an electronic switching circuit connected to be operated by the overrunresponsive means, the overrun switching circuit being connected to the pulse generator so as to prevent a constant portion, but not all, or the valve energizations throughout the overrun condition.
2 Assignments
0 Petitions
Accused Products
Abstract
This invention relates to fuel injection systems for internal combustion engines of the kind in which fuel is fed to an engine through one or more electrically operated fuel injection valves or injectors which are opened intermittently. The invention provides means for controlling the injection valve or valves under engine overrun conditions, and also means for controlling the fuel pressure to the injection valves in accordance with the engine induction passage pressure.
34 Citations
17 Claims
-
1. A fuel injection system for an internal combustion engine, comprising at least two electromagnetically operable fuel injection valve and a pulse generator for intermittently energizing each valve in timed relation to the engine-operaTing cycle, wherein there is provided an overrun control circuit comprising means responsive to an engine-operating parameter indicative of an engine-overrun condition and an electronic switching circuit connected to be operated by the overrunresponsive means, the overrun switching circuit being connected to the pulse generator so as to prevent a constant portion, but not all, or the valve energizations throughout the overrun condition.
-
2. A system as claimed in claim 1, including a plurality of fuel injection valves wherein the fuel injection valves are arranged in at least two groups and wherein means are provided which operate in response to an engine-operating parameter indicative of an engine-overrun condition in order to prevent energization of the valve or valves of at least one such group (but not of all the groups) under said overrun condition.
-
3. A system as claimed in claim 1, wherein the engine-operating parameter is the induction passage pressure downstream of the throttle valve of the engine.
-
4. A system as claimed in claim 1, wherein the engine-operating parameter is the rotational speed of the engine when the engine throttle valve is closed.
-
5. A system as claimed in claim 2, including a separate pulse generator for each group of fuel injection valves, a trigger device for triggering the pulse generators in timed relation to the engine-operating cycle, means for feeding one or more control signals to the pulse generators, which control signals vary as a function of parameters of engine operation in order to control the duration of the output pulses from the pulse generators and means for feeding the output pulses from each pulse generator to energize the injection valve or valves associated with that pulse generator.
-
6. A system as claimed in claim 5, wherein an electronic switching device is connected to at least one pulse generator, and means for controlling said switching device during the engine overrun conditions to inhibit the operation of said at least one pulse generator.
-
7. A system as claimed in claim 6, including a pressure-responsive transducer arranged in the induction passage of the engine downstream of the engine throttle valve, which transducer controls the electronic operation of the switching device.
-
8. A system as claimed in claim 6, including a throttle-operated switch is closed when the engine throttle valve is closed and which then passes a signal indicative of the rotational speed of the engine to control the operation of the electronic switching device.
-
9. A system as claimed in claim 6, for a four-cylinder internal combustion engine having one fuel injection valve for each cylinder, wherein the injection valves are divided into two groups each having two valves and two pulse generators are provided each of which supplies the energizing pulses to a group of two injection valves, and wherein an electronic switching device is connected to one of the pulse generators.
-
10. A fuel injection system as claimed in claim 1, including at least one electrically operated fuel injection valve which is opened intermittently, wherein means are provided which are responsive to an engine-operating parameter indicative of an engine-overrun condition and which operate to open the valve or valves only once every nth cycle of engine operation, where n is a number greater than one, under said overrun conditions.
-
11. A system as claimed in claim 10, wherein the engine parameter is the induction passage pressure downstream of the throttle valve of the engine.
-
12. A system as claimed in claim 10, wherein the engine parameter is the rotational speed of the engine when the engine throttle valve is closed.
-
13. A system as claimed in claim 10, including at least one pulse generator producing pulses for energizing the fuel injection valve or valves and which is controlled by at least one control signal varying as a function of a parameter of engine operation to control the duration of the output pulses fed to the fuel iNjection valve or valves.
-
14. A system as claimed in claim 13, wherein at least one pulse generator is triggered by a trigger device which operates in timed relation with the operating cycle of the engine, and an electronic switching device is connected to the or each pulse generator and is controlled during the engine-overrun condition so that it permits the operation of the or each pulse generator only in response to every nth trigger pulse to trigger the pulse generator.
-
15. A system as claimed in claim 14, wherein there is provided a plurality of fuel injection valves divided into at least two groups and a separate pulse generator is provided to energize each group of valves, a separate electronic switching device being connected to each pulse generator.
-
16. A system as claimed in claim 14, wherein operation of the or each electronic switching device is controlled by a pressure-responsive transducer arranged in the induction passage of the engine downstream of the throttle valve.
-
17. A system as claimed in claim 14, including a throttle-operated switch which is closed when the engine throttle valve is closed and which passes a signal generated under engine-overrun conditions to control the operation of the or each electronic switching device.
Specification