Internal-combustion engines – Starting device – Control of spark ignition during starting
Reexamination Certificate
2001-12-26
2004-04-13
Yuen, Henry C. (Department: 3747)
Internal-combustion engines
Starting device
Control of spark ignition during starting
C123S179170, C123S090150
Reexamination Certificate
active
06718928
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for starting a multi-cylinder internal combustion engine, especially of a motor vehicle wherein the position of a piston in a cylinder of the engine is determined. Fuel is injected into a combustion chamber of that cylinder whose piston is in a work phase.
The invention furthermore relates to a multi-cylinder internal combustion engine, especially of a motor vehicle. The internal combustion engine includes a detector device for determining the position of a piston in a cylinder of the engine and a fuel metering system for injecting fuel into a combustion chamber of that cylinder whose piston is in a work phase. Finally, the present invention relates also to a control apparatus for such a multi-cylinder internal combustion engine, especially of a motor vehicle.
BACKGROUND OF THE INVENTION
A method for starting a multi-cylinder internal combustion engine of the kind described above is known, for example, from DE 31 17 144 A1. The method described therein operates without an electric-motoric starter. At standstill of the engine, a quantity of fuel, which is necessary for a combustion, is injected and ignited in the combustion chamber of one or several cylinders whose piston is disposed in the work phase. Thereafter, fuel is injected and ignited in each of the combustion chamber(s) of the cylinders whose pistons execute the next work stroke as soon as the particular piston has reached the work position. In this way, the internal combustion engine can be configured without an electric starter and the components necessarily associated therewith. In addition, an electric storage battery of the engine can be dimensioned smaller because this battery no longer has to supply energy for the starter and the other electrical components.
In the known method for starting an internal combustion engine, the stroke (compression stroke, work stroke, discharge stroke, induction stroke) in which the individual pistons of the engine and the inlet and outlet valves of the combustion chamber are disposed must be precisely observed. This has the consequence that, in a 4-cylinder or 6-cylinder engine, for each stroke of the engine, only the combustion chamber of a single cylinder (namely, of the cylinder whose piston is in the work position) can be filled with fuel and the fuel can be ignited. The known method is limited to internal combustion engines wherein, on the one hand, the compression stroke, work stroke, discharge stroke and induction stroke are run through in a fixed sequence per cylinder and wherein, on the other hand, the distribution of the strokes to the individual cylinders is fixedly pregiven.
As a further state of the art, reference is made U.S. Pat. No. 6,050,232 A1 from which likewise a method is known for starting an internal combustion engine without an electric starter.
SUMMARY OF THE INVENTION
The present invention has the task of starting a multi-cylinder internal combustion engine without an electric starter in the simplest possible way, rapidly and yet reliably.
For solving this task, the invention proceeds from the method of the art mentioned initially herein and suggests that the inlet and/or outlet valves of at least one cylinder whose piston is disposed after top dead center is brought into a position corresponding to a work phase in advance of the start operation.
The method of the invention includes, for example, a camshaft-free control of the inlet and/or outlet valves. In this way, each inlet valve and outlet valve can be driven separately from the other valves and independently of the position of the camshaft. For a camshaft-free control, the inlet and/outlet valves are equipped individually or several in common with an actuator element. The actuator element can be operated hydraulically, piezoelectrically, electromagnetically, or in another way. A plurality of camshaft-free controls for the inlet and outlet valves are known from the state of the art, which can be utilized in combination with the present method according to the invention.
Alternatively, the method according to the invention includes, for example, a variable camshaft positioning device on the inlet end in order to adjust an early inlet closure of the inlet valve. The inlet camshaft can be so displaced that the inlet valves are opened in the induction phase only at the start for a short time and are thereby brought into a position corresponding to the work phase. In this way, an earlier inlet closure can be adjusted at the inlet end.
In the method according to the invention, the valves can be independently and, insofar as the free movement of the valve permits, freely opened or closed. In this way, it is achieved to change from an induction phase into a work phase and vice versa in advance of or during the starting operation. In the same manner, the change from a compression phase to a discharge phase and vice versa, is possible.
With the method of the invention, it is possible for the first time in a four or six-cylinder engine, at the beginning of the start operation, to bring two cylinders into the position corresponding to the work phase. Fuel is injected simultaneously into the combustion chambers of these two cylinders and the air/fuel mixture is simultaneously ignited. The double combustion leads to an especially intense start acceleration of the crankshaft and therefore to an especially short start operation. The double combustion offers adequate reserve in order to reliably overcome possible friction and compression resistances at the beginning of the start operation.
Fuel is then injected into the combustion chamber of a further cylinder disposed in the compression phase and the compressed air/fuel mixture is ignited. The injection begin in the combustion chamber of the additional cylinder can, if the injection pressure is high enough, be shifted into the advancing compression phase until shortly before reaching top dead center. Because of the second combustion, the rotational movement of the crankshaft is further accelerated. During the further course of the start operation, fuel is injected into the combustion chambers of cylinders disposed in the induction phase and the compressed air/fuel mixture, which is disposed in the combustion chambers, is ignited. Here too, the injections can take place alternatively also during the compression phase if the injection pressure is sufficiently high.
According to an advantageous embodiment of the present invention, it is suggested that:
the inlet and/or outlet valves of a further cylinder, whose piston is disposed ahead of top dead center, are brought into a position corresponding to a compression phase;
fuel is injected into the combustion chamber of the at least one cylinder disposed in the work phase;
the fuel, which is injected into the at least one cylinder, is ignited in the work phase;
fuel is injected into the combustion chamber of the additional cylinder disposed in the compression phase;
the fuel, which is compressed in the combustion chamber of the additional cylinder, is ignited; and,
in the further course of the starting operation, fuel is injected into the combustion chambers of cylinders disposed either in an induction phase or in a compression phase and the fuel, which is compressed in the combustion chambers, is ignited.
By igniting the fuel, which is injected into at least one cylinder in the work phase, a combustion is effected via which a forwardly directed rotational movement is imparted to the crankshaft of the engine. This rotational movement is continued or even accelerated by the ignition of the fuel compressed in the combustion chamber of the additional cylinder.
Finally, in the further course of the starting operation, fuel is injected into the combustion chambers and the fuel, which is compressed in the combustion chambers (that is, at the end of the compression phase or at the start of the work phase) is ignited. In the further course of the starting operation, the fuel is injected in the induction phase or, if the injection pressure is sufficiently high, into
Benninger Nikolaus
Brueggen Gerhard
Sieber Udo
Castro Arnold
Ottesen Walter
Yuen Henry C.
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