Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1989-01-05
1990-07-17
Dolinar, Andrew M.
Internal-combustion engines
Charge forming device
Fuel injection system
123491, F02D 4136, F02D 4106
Patent
active
049414496
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention is directed to a process for fuel injection in a multiple-cylinder internal combustion engine, wherein opening signals for the respective injection valves of the individual cylinders are produced as a function of the reference signals which are synchronous with the crankshaft, and all injection valves are first simultaneously opened once after the ignition switch is switched on and then the sequential opening signals for the sequential fuel injection are produced after the synchronization has been recognized.
An electronic fuel injection control system is known from DE-OS 32 43 456 in which all fuel injection valves are opened simultaneously immediately after closing an ignition switch in order to guide fuel to all cylinders of the internal combustion engine However, all fuel injection valves remain closed thereafter until the pistons of the cylinders have executed an intake stroke and the synchronization has been recognized. After the synchronization has been recognized, the fuel injection valves are opened successively in a preset sequence as a function of the reference signals which are synchronous with the crankshaft, and fuel is injected into the respective cylinder. The opening time during the mutual initial opening of all injection valves corresponds to the opening time after the synchronization has been recognized. A relatively large quantity of fuel is injected into opened inlet valves. No additional fuel reaches the respective combustion chambers until the start of the sequential fuel injections after the synchronization.
ADVANTAGES OF THE INVENTION
The process for fuel injection, according to the invention, is characterized in that during starting or after a disruption of the synchronization simultaneous, additional opening signals are fed to the injection valves, in a phase (a) until the synchronization has been recognized, and in that the additional simultaneous opening signals are fed to the injection valves in a phase (b) after the synchronization has been recognized for the cylinders which are not yet changed over to sequential operation. The invention provides the advantage of rapid switching over to sequential fuel injection. After starting or after a disruption of the synchronization, respectively, the allocation of fuel is effected simultaneously via all injection valves during a first phase, specifically so as to be delayed by a period of time t1 relative to the reference signal and in a relatively short opening interval T1 which can be preset. The opening interval T1 is smaller, according to the invention, than after the synchronization and depends particularly on the engine temperature, speed and the number of cylinders. There is an improved cold start behavior when the fuel injection into opened inlet valves is minimized. After the synchronization has been recognized, the injection is successively changed over to sequential operation, whereby fuel continues to be allocated to the rest of the cylinders, which are not yet synchronized, in parallel or simultaneous operation until the moment of the first closing of the corresponding inlet valves. Consequently, a fuel-air mixture is always present in the combustion chamber.
DRAWING
The process, according to the invention, is explained in more detail in connection with the following description with the aid of the drawing where:
FIG. 1 shows a time-dependency diagram with the signals for opening the injection valves of an internal combustion engine with six cylinders, wherein the successive fuel injection is effected after the recognition of the reference signal of the first cylinder, and
FIG. 2 shows a time-dependency diagram similar to FIG. 1, wherein, however, synchronization also takes place additionally after the recognition of the reference signal of the fourth cylinder.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows the time-dependency diagram of the signals for opening the injection valves E1 to E6 of an internal combustion engine with six cylinders. In the topmost line, the reference marks
REFERENCES:
patent: 4418674 (1983-12-01), Hasegawa et al.
patent: 4515131 (1985-05-01), Suzuki et al.
patent: 4528960 (1985-07-01), Mizuno et al.
Hoptner Wolfgang
Perenthaler Egbert
Schwarz Helmut
Dolinar Andrew M.
Robert & Bosch GmbH
Striker Michael J.
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