Internal-combustion engines – Starting device – Control of spark ignition during starting
Reexamination Certificate
2002-03-13
2004-05-25
Kwon, John (Department: 3747)
Internal-combustion engines
Starting device
Control of spark ignition during starting
C123S305000
Reexamination Certificate
active
06739300
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of starting a multi-cylinder, direct-injection, internal combustion engine, in particular of a motor vehicle, without using a starter motor. The position of a piston in a cylinder of the internal combustion engine is determined and fuel is injected into a combustion chamber of the cylinder whose piston is in the working phase, and the fuel is ignited immediately thereafter. This triggers the starting operation.
The present invention also relates to a memory element, in particular a read-only memory, a random-access memory or a flash memory for a control unit of an internal combustion engine, in particular in a motor vehicle. A computer program which is capable of running on a computing element, in particular on a microprocessor, is stored in the memory element.
The present invention also relates to a computer program capable of running on a computing element, in particular a microprocessor.
The present invention also relates to a direct-injection, multi-cylinder, internal combustion engine, in particular in a motor vehicle. The internal combustion engine provides for determining the position of a piston in a cylinder of the internal combustion engine, a fuel metering system for injection of fuel into a combustion chamber of the cylinder whose piston is in a working phase, and an ignition arrangement for igniting the fuel injected into the cylinder immediately after injection. This triggers the starting operation.
Finally, the present invention relates to a control unit of a direct-injection, multi-cylinder, internal combustion engine, in particular in a motor vehicle. The internal combustion engine provides for determining the position of a piston in a cylinder of the internal combustion engine, a fuel metering system for injection of fuel into a combustion chamber of a cylinder and an ignition arrangement for igniting the fuel injected into the cylinder at a preselectable time. The control unit controls the determining of the position of a piston, the fuel metering system and the ignition means for triggering the starting operation, so that the fuel metering system injects fuel into a combustion chamber of the cylinder whose piston is in a working phase, and the ignition arrangement ignites the fuel injected into the cylinder immediately after injection.
BACKGROUND INFORMATION
German Published Patent Application No. 197 42 969 describes a method of starting a multi-cylinder, direct-injection, internal combustion engine in which the serial injection sequence of the internal combustion engine is canceled by a parallel connection of working cycles via a suitable valve control for a rapid torque buildup. To this end, the internal combustion engine has intake and exhaust valves that are freely operable, inasmuch as allowed by free travel of the valves.
During at least one revolution of the crankshaft of the internal combustion engine, the intake valves of the cylinders whose pistons are at top dead center at the same time are opened. After executing an intake stroke and compression stroke, the compressed fuel in the combustion chambers of these cylinders is ignited simultaneously. Thus, two cylinders go through the working phase at the same time. Following the working stroke, the combustion gases are ejected through the exhaust valves of the cylinders which are opened at the same time. In this method, however, the starting operation is not accomplished by combustion in the cylinders but instead by an electric starter motor which is provided separately. It executes an intake stroke and/or a compression stroke before the first ignition.
A method of starting an internal combustion engine of the type described above without using a starter motor is described in German Published Patent Application No. 100 20 104, for example. In the method described, no intake stroke or compression stroke is carried out before the first ignition, and instead the starting operation is triggered by the ignition alone. The advantage of such a direct start of the internal combustion engine is in particular that it is possible to eliminate an electric drive motor for the start or for execution of an intake stroke and/or a compression stroke before the first ignition. Due to the absence of a compression stroke before the first ignition, however, an effective mechanism for preparing a fuel/air mixture contained in the combustion chamber is omitted.
Therefore, there is a need to improve upon the processing of the mixture at the beginning of the starting operation in the case of direct start of a multi-cylinder, direct-injection, internal combustion engine without using a starter motor.
SUMMARY OF THE INVENTION
The present invention proposes that as the starting operation continues immediately after ignition of fuel in the cylinder which is in the working phase, fuel is injected into a combustion chamber of another cylinder where the piston is in an intake phase, and the injected fuel is ignited while still in the intake phase.
The method according to the present invention is suitable for starting a direct-injection internal combustion engine having at least two cylinders without using a starter motor. Prior to beginning the method, the position of the rotation angle crankshaft of the internal combustion engine, i.e., the position of the pistons in the cylinders of the internal combustion engine, is determined. In the case of an internal combustion engine having four or more cylinders, the piston of at least one cylinder will be in the working phase. If in the case of an internal combustion engine having fewer than four cylinders, no piston of a cylinder is in the working phase, the intake and exhaust valves of the cylinder which is in the intake phase are brought into a position corresponding to the working phase, i.e., the intake and exhaust valves are closed.
For free operation of the intake and exhaust valves, a camshaft-free control is provided, for example, with which each intake and exhaust valve may be controlled separately from the other valves and independently of the position of the camshaft. For camshaft-free control, the intake and/or exhaust valves are equipped with a regulating unit either individually or jointly for a plurality of valves. The regulating unit may be actuated hydraulically, piezoelectrically, electromagnetically or by some other method. A plurality of camshaft-free controls for intake and exhaust valves are described from related art and may be used in conjunction with the present invention.
As an alternative, the intake and exhaust valves may have, e.g., a variable camshaft control element on the intake side and a variable valve lift for free actuation. It is thus possible to adjust the intake camshaft so that the intake valves are opened briefly in the intake phase only at the beginning and are thus brought into a position corresponding to the working phase. In this way, earlier closing of the intake may be set on the intake side.
Fuel is injected into the combustion chamber of the cylinder which is in the working phase, and the fuel is ignited immediately thereafter, thus starting the initial rotary motion of the internal combustion engine which thus triggers the starting operation. As the starting operation continues, fuel is injected into the combustion chamber of another cylinder in which the piston is in an intake phase immediately after ignition of the fuel/air mixture in the cylinder which is in the working phase. To further accelerate the rotary motion of the internal combustion engine, fuel injected into the combustion chamber of the additional cylinder is ignited while still in the intake phase.
Injection of fuel into the combustion chamber of a cylinder in the intake phase before the second combustion has a positive effect on preparing the mixture for the second combustion. At the start of the intake phase of a cylinder, the injector of the cylinder is opened to allow air to be drawn into the combustion chamber of the cylinder. Due to the intake of air through the intake valve, swirls develop in the com
Ackermann Manfred
Sieber Udo
Kenyon & Kenyon
Kwon John
Robert & Bosch GmbH
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