JP2761398B2 - Starting device for internal combustion engine - Google Patents

Description

The present invention relates to a starting device for an internal combustion engine.

[Prior Art] A conventional internal combustion engine requires special starting means such as a starter motor and a recoil starter in order to forcibly rotate a crankshaft when the internal combustion engine is started. This is the same in a direct injection type internal combustion engine that injects fuel directly into a cylinder combustion chamber.

[Problem to be Solved by the Invention] Here, the starter motor is driven by a battery, but the charging voltage of the battery may not be sufficient,
In this case, a necessary starter motor cannot rotate the crankshaft, and a smooth start may not be performed. Also,
When using a starting means such as a recoil starter,
As a result, the structure becomes more complicated or larger, and the starting operation requires skill depending on the internal combustion engine, and smooth starting may be difficult.

The present invention has been made in view of such prior art, and has as its object to provide a starting device for an internal combustion engine that can start the engine without using separate starting means such as a starter motor and a recoil starter. To offer.

Means for Solving the Problems In order to achieve such an object, the present invention provides a cylinder discriminating means for discriminating a cylinder in which a piston is stopped after a top dead center and before an exhaust stroke. Fuel supply means for directly injecting fuel into the engine combustion chamber at the time of starting, and ignition means for sequentially supplying an ignition signal to each cylinder, wherein the cylinder discriminating means, when the ignition signal is supplied to a predetermined cylinder, the other It is configured to derive and hold a voltage corresponding to the ignition signal until the next ignition signal is supplied to the cylinder, and the piston immediately before the stop of the engine is stopped after the top dead center and before the exhaust stroke. By detecting the held voltage for the cylinder, a cylinder corresponding to the voltage is determined as a starting cylinder.

[Operation] When the internal combustion engine is stopped, the inside of the cylinder is gradually replaced with fresh air. Therefore, the cylinder in which the piston is stopped after the top dead center and before the exhaust stroke is: By supplying an appropriate fuel to the combustion chamber, a combustible air-fuel mixture is generated. The air-fuel mixture ignites by spark ignition of the air-fuel mixture in the combustion chamber. Accordingly, the piston descends due to the pressure of the deflagration and the crankshaft starts rotating, and thus the internal combustion engine starts to start.

EXAMPLES The present invention will be described below based on examples shown in the drawings.

FIG. 1 is an overall configuration diagram including a control circuit according to an embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a direct injection type internal combustion engine, which includes a cylinder 12, a piston 14, a spark plug 16, a crankcase 18, a crankshaft 20, and a connecting rod 22.
A crank chamber 24 is formed in the crankcase 18, and only air is supplied to the crank chamber 24 via a reed valve 28.
An intake passage 26 to be supplied into the inside 24 is open. Crankcase
The air introduced into the cylinder 24 is pre-pressed by the piston 14 moving up and down in the cylinder 12, and is introduced into the combustion chamber 34 from the scavenging passage 30 via the scavenging port 32.

36 is an exhaust port, 38 is an exhaust passage, and the exhaust port 36
The scavenging port 32 is opened and closed by the vertical movement of the piston 14.

Numeral 40 is a fuel tank, numeral 42 is a strainer, numeral 44 is an electric fuel pump.Fuel pumped from the electric fuel pump 44 is directly injected into the combustion chamber 34 of the cylinder via an electromagnetic fuel injection valve 46. . Reference numeral 48 denotes a pressure regulator which keeps the fuel pressure constant by recirculating a part of the fuel to the fuel tank 40 when the fuel pressure fed from the electric fuel pump 44 to the injection valve 46 becomes equal to or higher than a predetermined pressure. .

The injection valve 46 is electronically controlled by a central processing unit (hereinafter referred to as a CPU) 50. During normal operation, the CPU 50 receives a pressure signal of the crank chamber 24 from a pressure sensor 52 attached to the crankcase 18 and a crank signal. The crank angle signal from the crank angle sensor 54 attached to the shaft 20 and the crankshaft reference angle signal from the pulsar coil 56 are fetched and subjected to arithmetic processing to determine an appropriate fuel injection timing and injection amount. Activate 46.

In this embodiment, the ignition timing of the ignition plug 16 is determined by the CDI unit 60 that applies the voltage generated from the charge coil 58 to the primary coil of the ignition coil 62 at the optimum ignition timing by a signal from the pulser coil 56.

The above is the control configuration of the ignition timing and the fuel injection during the normal operation of the internal combustion engine 10, but an embodiment of the starting device of the present invention that does not require cranking will be described in detail below.

Reference numeral 66 denotes a starting cylinder discriminating circuit, which is a cylinder in which the piston 14 is stopped after the top dead center and before the exhaust stroke, that is, the exhaust port, based on a signal from the crank angle sensor 54 substantially. The cylinder in which the cylinder 36 is not opened with respect to the cylinder 12 is determined, and the signal is sent to the CPU 50.

The CPU 50 fetches the engine temperature signal from the temperature sensor 68, thereby determining the fuel injection amount in the cylinder in which the piston 14 can be started, that is, the injection time of the injection valve 46, and the ignition timing necessary for starting, that is, the injection timing. It is determined when the spark plug 16 is to be spark-ignited after the fuel injection from the valve 46. The output signal from the CPU 50 is sent to the injection valve 46 and the CDI unit 60, which injects fuel into the combustion chamber 34 of the cylinder determined by the cylinder determination circuit 66 and ignites it, and deflagrates the air-fuel mixture in the combustion chamber 34. Then, the internal combustion engine is started. In FIG. 1, reference numeral 70 denotes a main switch.

The cylinder discrimination circuit 66 determines the cylinder for starting, that is, the cylinder in which the piston is stopped at a position after the top dead center and before the exhaust stroke, basically based on the crankshaft 20 from the crank angle sensor 54. Although it is based on the angle, in the case of a six-cylinder or three-cylinder internal combustion engine, the relevant cylinder can be determined as follows.

That is, when the six-cylinder or three-cylinder internal combustion engine is stopped, the piston of one cylinder always stops at a position of 30 to 40 degrees before the top dead center, and therefore, the piston of some other cylinders stops after the top dead center. There is always a piston that stops at a position of 80 to 90 degrees, and this cylinder has not yet opened the exhaust port 36, and is the relevant cylinder for starting.

Therefore, in the case of a three-cylinder internal combustion engine based on FIG. 2, first, the ignition signals of the respective cylinders are sent at intervals of 120 degrees from each other. Therefore, for example, the voltage corresponding to the first cylinder is derived and held by the ignition signal of the first cylinder, this voltage is released by the ignition signal of the second cylinder, and the voltage corresponding to the second cylinder is derived and held at the same time. The voltage of the second cylinder is released by the ignition signal of the third cylinder and the third
The voltage of the cylinder is derived and held, and this is repeated. Here, for example, when the third cylinder stops at 30 to 40 degrees before the top dead center, a signal for releasing the hold voltage of the second cylinder is not input, and
Therefore, the voltage for the second cylinder is held as it is. The second cylinder is a cylinder whose piston is stopped at a position of 80 to 90 degrees after the top dead center. Therefore, the cylinder corresponding to the held voltage (second cylinder) is determined as the corresponding cylinder for starting. can do.

Next, FIG. 3 shows an embodiment of a control routine of the starting device of the present invention. First, after the main switch 70 is turned on, the engine (engine) temperature is detected based on a signal from the temperature sensor 68, and the fuel injection amount is determined based on the detected signal. Thereafter, a start cylinder to be injected with fuel is read out from a RAM (not shown) connected to the CPU 50, and fuel is injected into this cylinder. At the same time, the corresponding cylinder is ignited by the ignition plug 16 at the optimum ignition timing, and the engine is started. Here, it is determined whether or not the engine has been started, and if not, the steps after the fuel injection to the corresponding cylinder are performed again. When the engine has been started, the engine is operated in the normal operation mode. Thereafter, it is determined whether or not the engine is stopped. If the engine is not stopped, the operation is continued in the normal mode. If the engine is stopped, the corresponding cylinder for the next start is determined. Then, the determined cylinder is recorded, and the control routine ends.

According to the control routine shown in the flowchart of FIG. 3, there is an advantage that a cylinder corresponding to the next start can be determined using the ignition signal immediately before the engine is stopped.

Next, FIG. 4 shows another embodiment of the control routine.
Here, first, the main switch 70 is turned on, then the corresponding cylinder for starting is determined, and thereafter, the engine temperature is detected, the fuel injection amount is determined, the relevant cylinder is read, the fuel is injected into the relevant cylinder, and the corresponding cylinder is started. The engine is started by the ignition of. If the engine is not started, the corresponding cylinder is read again, and if the engine is started, control in the normal mode is performed. In the control routine of FIG. 4, even if the crankshaft rotates for some reason after the engine is stopped until the next start, the cylinder is determined by detecting the crank angle after the main switch is turned on, and so on. It is possible to prevent fuel injection and ignition from being performed on a cylinder other than the corresponding cylinder.

[Effects] As described above, according to the present invention, there is an excellent effect that the internal combustion engine can be started without the need for an external starting mechanism such as a starter, which was conventionally required.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a starting device for an internal combustion engine according to the present invention, FIG. 2 is a graph showing an example of a discriminating method of a cylinder discriminating circuit in the embodiment, and FIG. FIG. 4 is a flowchart showing one embodiment of a control routine, and FIG. 4 is a flowchart showing another embodiment. 10 Internal combustion engine 14 Piston 36 Exhaust port 46 Injection valve 50 CPU 66 Cylinder discrimination circuit

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Claims (1)

(57) [Claims] Cylinder discriminating means for discriminating a cylinder in which a piston is stopped after a top dead center and before an exhaust stroke; fuel supply means for injecting fuel directly into an engine combustion chamber at least at the time of starting; The cylinder discriminating means, when the ignition signal is supplied to a predetermined cylinder, supplies a voltage corresponding to the ignition signal until the next ignition signal is supplied to another cylinder. It is configured to derive and hold, and corresponding to this voltage by detecting the held voltage for a cylinder in which the piston immediately before stopping the engine is stopped after the top dead center and before the exhaust stroke. A starting device for an internal combustion engine, wherein a cylinder is determined as a starting cylinder.