JPS6228314B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for determining a cylinder to which an ignition signal is supplied (hereinafter referred to as an ignition cylinder) in a multi-cylinder internal combustion engine.

In an internal combustion engine equipped with an electronically controlled fuel injection device, the ignition cylinder is determined, and fuel injection is performed in each cylinder based on this determination. Conventionally, as means for determining the ignition cylinder in such a case, for example, a crank angle sensor is provided close to the engine crankshaft or the distributor camshaft, and the sensor detects the top dead center of the specified cylinder or other specified positions. There is a system in which the determination is made based on a reference signal generated at a crank angle position and a count number of unit signals generated for each unit angle of the crank angle, for example, "1".

However, in such conventional means, the structure of the crank angle sensor is complicated and large, which not only increases cost, but also requires heat resistance because it is installed near the engine body. Further, the circuit that processes the signal from the crank angle sensor to determine the cylinder also has a complicated configuration. In addition, there are systems in which cylinder discrimination is performed by a combination of the ignition signal of a predetermined cylinder and the ignition signals of all cylinders (see JP-A-50-111445, JP-A-53-48130, etc.) ), the configuration of the cylinder discrimination circuit was also complicated in this case.

The present invention has been devised in view of such conventional problems, and has a structure that can be implemented at low cost, consisting of a cylinder discrimination sensor with a simple structure, a flip-flop, and a discrimination circuit discriminating circuit provided in a microcomputer. An object of the present invention is to provide an ignition cylinder discriminating device for a multi-cylinder internal combustion engine that can reliably discriminate.

The present invention will be explained below based on illustrated embodiments. Figure 1 shows the present invention in which the ignition cylinder order is #1→#2.
A control block diagram of an embodiment applied to a 4-cylinder engine in which the engine speed is ➝#4➝#3 is shown. In the figure, an ignition signal 1 is generated from the primary side of an ignition coil (not shown) at each ignition timing for each cylinder. The ignition timing is set at α (α _MAX ≒ 40°,
It is controlled at a time when the angle is advanced by α _MIN ≒0°). The waveform shaping circuit 2 shapes the ignition signal 1 into a rectangular pulse signal and outputs it to an iRQ (interrupt routine) terminal of a controller 3 constituted by a microcomputer. The cylinder discrimination sensor 4 is provided close to the peripheral wall of the camshaft 11 as shown in FIG.
It consists of a simple pulse generator equipped with b. Then, at a rotational position of the camshaft 11 advanced by a predetermined crank angle β before the top dead center of a predetermined cylinder, for example, cylinder #1 in this embodiment, the convex portion 11a provided on the peripheral wall of the camshaft 11 is connected to the core 4 of the sensor 4.
The convex portion 11a is disposed so as to face the end surface a.
The electromotive force generated in the coil 4b when the cylinder passes through the end face of the core 4a is output as a discrimination signal for cylinder #1. Here, β is α _MAX < β < 180
The value is set to ゜. That is, after the ignition timing of cylinder #3, which is ignited one cylinder before cylinder #1,
Further, the sensor 4 is set to output a signal before the ignition timing of cylinder #1. The waveform shaping circuit 5 shapes the signal from the sensor 4 into a rectangular pulse signal and outputs it to the set terminal of the flip-flop 6. When the flip-flop 6 inputs the signal from the sensor 4, it outputs a "1" signal to the PORTA terminal, which is the non-interrupt input terminal of the controller 3, and when the flip-flop 6 inputs a "1" signal from the PORTB terminal to the reset terminal. The output signal is reset to "0".

Next, the operation of this embodiment will be explained with further reference to FIGS. 3 and 4.

Now, when a discrimination signal for cylinder #1 is output from the cylinder discrimination sensor 4 during the compression stroke of cylinder #1 due to engine rotation, this signal is inputted to the flip-flop 6 via the waveform shaping circuit 5; The output “1” signal is input to the PORTA terminal of the controller 3. Thereafter, when the ignition signal for cylinder #1 is output from the primary side of the ignition coil, the interrupt routine shown in FIG. 4 is started in the controller 3. That is, when the ignition signal is input, the cylinder count number previously stored in the memory circuit section of the controller 3 is erased, and a new cylinder count number obtained by adding 1 to the previous cylinder count number is stored. Incidentally, the cylinder count number is used to determine the ignition cylinder other than cylinder #1, as will be described later. Next, it is determined whether the input signal to the PORTA terminal is "1" or "0". Here, as mentioned above, since the signal to the PORTA terminal is "1", it is determined that the ignition cylinder is #1, and in this case, the cylinder count stored in the storage section is set to "0". After resetting,
Control of fuel injection and the like in cylinder #1 is performed. When the control of cylinder #1 is completed, a one-shot signal of "1" is output to the PORTB terminal, this signal is input to the flip-flop 6, and the output signal of the flip-flop 6, that is, the input signal of the PORTA terminal becomes "0". will be reset to

Next, when the ignition signal for cylinder #2 is output, 1 is added to the previously reset cylinder count number 0, and a new cylinder count number 1 is stored. Next, it is determined that the input signal to the PORTA terminal is "0", and in this case, the ignition cylinder corresponding to the cylinder count number is determined. Here, since the cylinder count number is 1 as described above, the corresponding control of ignition cylinder #2 is performed in the same manner as described above.

If the ignition signals for cylinder #4 and cylinder #3 are inputted to the control circuit 3 according to the ignition order, the cylinder count numbers will be 2 and 3, respectively, in the same manner as described above.
Since the input signal of the PORTA terminal remains “0”, cylinder #4 and cylinder #3 corresponding to the cylinder count number
It is determined that cylinder #4 and cylinder #3 are controlled.

In the ignition cylinder discriminating device having such a configuration, the cylinder discriminating sensor 4 detects one cycle per cycle of a predetermined cylinder.
Since it is only necessary to output a signal at a rate of 3 times, an extremely simple magnetic induction type, inexpensive and small type can be used, and the installation space is small. In addition, as the cylinder discrimination sensor, an optical sensor such as a light emitting diode may be used, and in this case as well, the requirements for low cost and small size can be met. Further, the controller 3 also directly determines the ignition cylinder by inputting the ignition signal, and the processing steps are simple, so the reliability is excellent.

In a motorcycle or the like, for example, in a four-cylinder engine having the same ignition order as in the above embodiment, cylinders whose pistons are in the same phase in the compression stroke and the exhaust stroke, that is, cylinder #1, cylinder #4, cylinder There is one in which cylinder #2 and #3 are ignited at the same time, with one cylinder ignited dry during the exhaust stroke. In the present invention, the signal from the cylinder discrimination sensor is output only during the compression stroke of a predetermined cylinder, so by determining the presence or absence of this signal, the ignition cylinder during the compression stroke and the empty cylinder during the exhaust stroke are determined. The cylinder to be ignited can be determined, and combustion injection control etc. can be performed without any trouble. I can do it. The ignition cylinder discrimination device according to the present invention can be used not only for fuel injection control but also for ignition control, etc. In this case as well, the next ignition cylinder is discriminated based on the memorized result of the most recently ignited cylinder. This can be used to perform highly accurate ignition timing control for each cylinder, such as controlling the determined ignition timing.

In addition, the present invention can be used as long as it outputs an ignition cylinder discrimination signal to a control device that performs control for each cylinder based on the stored discrimination result of the ignition cylinder. Furthermore, in the case of a two-cylinder engine, the cylinders can be identified by simply determining the flip-flop signals, so the cylinder counting circuit can be omitted. Further, for example, if an interrupt process is performed to set a flag when a discrimination signal for a given cylinder is input, and then the flag is checked when an ignition signal is input, cylinder discrimination can be performed without using a flip-flop. In this case, a special input port for interrupt processing is required to input the cylinder discrimination signal. However, in the case of a controller for controlling an internal combustion engine, it is necessary to perform a large number of interrupt processes based on engine rotation signals, timer signals inside the controller, etc. (readable in real time) is often not available, and using one with additional ports increases the cost.

In this regard, the present invention uses a flip-flop to easily read the flip-flop signal held at the normal input port when the ignition signal is input, without preparing a special interrupt processing port for cylinder discrimination. Therefore, a highly reliable cylinder discrimination function can be obtained.

In addition, as described in the conventional example, if the cylinder discrimination signal of a given cylinder is synchronized with the ignition signal of the same cylinder, cylinder discrimination using a flip-flop as in the present invention cannot be performed, and the discrimination circuit becomes complicated. I end up. That is, in the present invention, by using a flip-flop and a cylinder discrimination sensor that outputs a cylinder discrimination signal before a predetermined ignition timing, it is possible to obtain a cylinder discrimination device that is as inexpensive and reliable as possible.

As explained above, according to the present invention, there is provided a cylinder discrimination sensor that outputs a signal before the ignition timing of a predetermined cylinder, and a cylinder discrimination sensor that outputs a signal before the ignition timing of a predetermined cylinder, and a sensor that determines the presence or absence of the signal from the sensor and the number of inputs of the ignition signal in accordance with the input of the ignition signal. Since it is constructed with a circuit that discriminates the ignition cylinder by detection, the construction is simple, a small sensor can be used, and the installation space can be small. Further, since the discrimination circuit is configured to discriminate the ignition cylinder by reading the flip-flop signal in response to the input of the ignition signal, it has various advantages such as low cost and excellent reliability.

[Brief explanation of the drawing]

Fig. 1 is a control block diagram showing one embodiment of the present invention, Fig. 2 is a front view showing a cylinder discrimination sensor used in the above embodiment, and Fig. 3 shows various signals and reference positions generated in the above embodiment. The figure shown in FIG. 4 is a flowchart showing the operation of the controller of the same embodiment. 1...Ignition signal, 2, 5...Waveform shaping circuit, 3
...Controller, 4...Cylinder discrimination sensor, 6...
…flipflop.

Claims (1)

[Claims] 1. In an ignition cylinder discrimination device for a multi-cylinder internal combustion engine that outputs an ignition cylinder discrimination signal to an engine control device that performs control for each cylinder based on the discrimination result of the most recently ignited cylinder, a cylinder discrimination sensor that generates a signal; a flip-flop that inputs the signal from the sensor and outputs a signal of "1" to a non-interrupt input terminal of the microcomputer; The ignition signal generated from the side and the signal from the flip-flop are input, and when the ignition signal is input, the input signal from the flip-flop is "1".
When it is detected that the cylinder corresponding to the ignition signal is the predetermined cylinder, it determines that the cylinder corresponding to the ignition signal is the predetermined cylinder and resets the flip-flop signal to "0",
and a determination circuit that determines that the cylinder corresponding to the ignition signal is a cylinder other than the predetermined cylinder when it is detected that the input signal from the flip-flop is "0" when the ignition signal is input. Features: Ignition cylinder discrimination device for multi-cylinder internal combustion engines.