DK200000132A - Fremgangsmåde til brændselsindsprøjtning i cylindre i en flercylindret dieselmotor, og et brændselsindsprøjtningssystem - Google Patents

Description

PATENT CLAIMS 1. A method of injecting fuel into cylinders in a multi-cylinder diesel engine, where a high pressure pump supplies fuel to an accumulator that is common to several cylinders, and at least two fuel injectors receive fuel from the accumulator during an injection sequence of fuel into an individual cylinder, which injection sequence initiates by opening the fuel injectors one after the other with a mutual time lag, and during the injection sequence the injectors inject mutually different amounts of the same kind of fuel into the combustion chamber of the cylinder, characterized in that the injector injecting the largest amount of fuel at the injection sequence is positioned so that averaged over at least 9 injection sequences the distribution of injected fuel is made substantially more even in the circumferential direction of the combustion chamber. 2. A method according to claim 1, characterized in that from one injection sequence to the next, the position of the injector injecting the largest amount of fuel is shifted from one injector to another, preferably in a cyclic manner that uses all of said at least two fuel injectors on the cylinder an equal number of times. 3. A method according to claim 1, characterized in that each injector is positioned with a circumferential distance to the neighbouring injector in the air swirl direction in the combustion chamber, and that the injector injecting the largest amount of fuel is positioned with the largest circumferential distance to its neighbouring injector. 4. A method according to claim 3, characterized in that the circumferential distances separating the injectors are substantially proportional to the amounts of fuel injected by the injectors relative to the aggregate amount of fuel injected during the injection sequence at 100 per cent engine load. 5. A fuel injection system in a multi-cylinder diesel engine, having a high pressure pump supplying a main fuel to an accumulator that is common to several cylinders, and at least two fuel injectors mounted on the individual cylinder, each injector having a control valve for opening or closing a fuel line from the accumulator to the injector, and an electronic control unit that can open the control valves one after the other with a mutual time lag, characterized in that the injectors are located with uneven circumferential spacing in the combustion chamber, and that the injector opened first by the electronic control unit is positioned with the largest circumferential distance to its neighbouring injector in the air swirl direction in the combustion chamber. 6. A fuel injection system according to claim 5, characterized in that the circumferential distances separating the injectors are substantially proportional to the amounts of fuel injected by the injectors relative to the aggregate amount of fuel injected during a full injection sequence at 100 per cent engine load. 7. A fuel injection system according to claim 5 or 6, characterized in that the control valve on each injector has only two positions, an open position where the injector is fully connected to the accumulator and a closed position where the injector is barred from the accumulator. 8. A fuel injection system according to any one of claims 5-7, characterized in that the cylinders of the engine have a bore of at least 21 cm. 9. A fuel injection system according to any one of claims 5-8, characterized in that the engine is a two-stroke crosshead engine.