JPH0729237Y2 - Engine start condition detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a starting state detection device for accurately determining the starting state of an internal combustion engine such as an automobile, and in particular, allows the starter motor to be started only when the clutch is off. The present invention relates to an engine starting state detection device suitable for use in a vehicle.

(Prior Art) In recent years, electronic control of internal combustion engines such as automobiles is rapidly advancing, and in such control, it is necessary to accurately detect the operating state of the engine. One of such operating states is an engine starting state, and at the time of starting, the microcomputer detects and determines the cranking state to correct the fuel amount.

As a conventional engine start state detection device of this type,
For example, there are those disclosed in Japanese Utility Model Laid-Open No. 59-40580 and Japanese Utility Model Laid-Open No. 59-85377, which are shown in FIG. In the figure, 1 is a battery, 2 is a starter motor, 3 is a start relay, 4 is a clutch switch, 5 is an ignition key switch, 6 is a microcomputer for engine control, and 7 is a microprocessor for performing arithmetic processing in the microcomputer. (CPU) and 8 are fuses. Here, the microcomputer 6 receives the start signal from the S terminal or R terminal of the ignition key switch 5. In this case, the S terminal is connected to the starter motor 2 via the start relay 3, but the R terminal is not directly connected to the starter motor 2. R terminal is S terminal
Turns on when turned on (the battery voltage must be below),
Turns off when turned off. Therefore, the microcomputer 6 determines the ON / OFF state of the starter motor 2 from the state of the S terminal or the R terminal.

(Problems to be solved by the invention) However, in such a conventional engine starting state detecting device, the start relay 3 is connected in series between the ignition key switch 5 and the starter motor 2, and Since the start signal of the microcomputer 6 is inputted from the S terminal or the R terminal of the ignition key switch 5, the engine start state may be erroneously determined in the following cases.

That is, the start relay 3 does not energize unless the clutch is disengaged and the clutch switch 4 is turned on, which is to prevent the vehicle from running out of control at the time of starting. Therefore, for example, when the ignition key switch 5 is turned on without disengaging the clutch, the microcomputer 6 determines that the starter motor 2 is rotating because the ignition key switch 5 is on, and the cranking state should be established. However, since the clutch is not disengaged, the start relay 3 is not actually excited and the starter motor 2 is not energized, so that the starter motor 2 does not rotate and the engine does not crank. In such a case, the actual operating state and the discriminated state of the microcomputer 6 do not match, and the engine starting state is erroneously recognized.

On the other hand, in order to eliminate such a problem, for example, the sixth
As shown in the figure, when the input of the start signal to the microcomputer 6 is taken out from between the start relay 3 and the starter motor 2, the following new problems occur. That is, when the permanent magnet made of ferrite is used as the magnet of the starter motor 2 instead of the electromagnet, the ignition key switch 5 is turned off.
However, since the magnetic force does not suddenly become zero, the starter motor 2 generates power for a while (reverse electromotive force is not generated due to residual magnetic flux). Therefore, as shown in FIG. 7, the level of the input signal (start signal) does not become zero at the timing of turning off the ignition key switch 5, but gradually decreases. That is, at this OFF timing, the start signal is sent to the CPU 7 by the back electromotive force from the starter motor 2.
Therefore, the microcomputer 6 determines that the start signal is at the ON level for a longer time than it actually is. Therefore, in such a case, for example, in an engine in which the fuel amount increase correction is performed at the time of starting, the starting amount is increased unnecessarily for a long time, resulting in deterioration of fuel efficiency. From the above, a device that can correctly determine the starting state of the engine is desired.

(Object of the invention) Therefore, the present invention pays attention to the temporary decrease of the battery voltage at the time of starting the engine, and detects not only the operation of the starter switch but also the state of the battery voltage to determine the start of the engine. The purpose is to ensure the accuracy of.

(Means for Solving Problems) In order to achieve the above object, the engine starting state detecting device according to the present invention is used when the starting operation of the starter motor is performed as shown in the basic conceptual diagram of FIG. A start signal generating means a for outputting a start signal, a voltage detecting means b for detecting a power supply voltage supplied to the starter motor, and a start signal from the start signal generating means a are detected by the voltage detecting means b. Further, it is provided with a discriminating means c for discriminating the starting state of the engine when the power supply voltage drops below a predetermined value, and a storing means d for storing the engine starting state discriminated by the discriminating means c.

(Operation) In the present invention, not only the operation of the starter switch but also the state of the battery voltage is detected. That is, since the determination condition is added to the temporary decrease phenomenon of the battery voltage accompanying the actual engine start, the engine start determination can be made more accurate.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

2 and 3 are views showing a first embodiment of an engine starting state detecting device according to the present invention.

First, the configuration will be described. In FIG. 2, reference numeral 11 denotes a battery, and the (+) terminal of the battery 11 is connected to the starter motor 12 and also connected to the ignition key switch 14 via the fuse 13 and the EGI via the fuse 15.
Connected to relay 16. Starter motor 12 is amateur
It consists of 17, field coil 18, pull-in coil 19 and main contact 20, and pull-in coil 19 is a start relay.
It is connected to the ignition key switch 14 via 21. The ignition key switch 14 has a common terminal C
It has AC, IG, R, and S terminals, and when a manual start operation is performed, the common terminal C is connected to the R and S terminals to supply the battery voltage (corresponding to a start signal) to the start relay 21. And output to the microcomputer 22.

The ignition key switch 14 has a function as a start signal generating means. The start relay 21 has a coil 21c and an a-contact 21a, and the coil 21c is grounded via a clutch switch 23. The clutch switch 23 closes its contact when the clutch is depressed. When the start signal is input to the start relay 21, when the clutch switch 23 is in the ON state, the start relay 21 is excited to close the a-contact 21a, and the battery voltage is changed to the starter motor 1
The pull-in coil 19 of 2 is supplied. When the pull-in coil 19 is excited, the starter motor 12 closes the main contact 20 and receives the battery voltage from the field coil 18 and the amateur 17 to activate the starter motor 12 to crank the engine body.

On the other hand, the EGI relay 16 has a coil 16c and an a contact 16a, and based on a command from the microcomputer 22, the coil 16c
Is excited to close the a contact 16 to supply (read) the battery voltage to the microcomputer 22. The read command is issued during a period when the start signal is output from the ignition key switch 14, as will be described later with reference to a flowchart. EGI relay 16 is a microcomputer 2
2 has a function as a voltage detecting means, and the microcomputer has a function as a discriminating means and a storing means by itself. The microcomputer 22 has a CPU 23, a ROM 24,
It is composed of RAM 25 and I / O port 26. CPU23 is ROM
I / O port 2 according to the program written in 24
Take in external data required from 6 or RAM25
The necessary processing values and the like are arithmetically processed while exchanging data with the I / O port, and the processed data is output to the I / O port 26 as necessary. The ROM 24 stores the calculation program in the CPU 23, and the RAM 25 stores the external data used for the calculation in the form of a map or the like.

Next, the operation will be described.

FIG. 3 is a flowchart showing a program for detecting the starting state. First, at P ₁ , it is determined whether or not the start operation of the ignition key switch 14 is manually performed and the start signal (application of the battery voltage) is input to the start relay 21 and the microcomputer 22, and when it is not input,
The start flag ST is set to [φ] at P ₂ and stored. The start flag ST is a flag indicating whether or not the engine is actually cranking. When ST = 1, it means that the engine is actually cranking. When ST = φ, it means that the engine is not cranking. Show. This start flag ST is used as electronic control information of the engine, and, for example, the fuel increase correction at the time of start is performed based on the information of this flag. Therefore, the high accuracy of the start flag ST leads to the certainty of engine control.

Even if the start signal is input at P ₁ , for example, if the clutch is not disengaged, it cannot be said that the regular series of procedures for starting is performed, and only the ignition key switch 14 is manually operated. It is also possible. Therefore, in order to avoid such a problem, the battery voltage V _B during the input period of the start signal is compared with the voltage determination level V _S during cranking at P ₃ . V _S is a value corresponding to a drop in the battery voltage when current is flowing through the starter motor 12 during cranking, and is set to the level shown in FIG. 7. When V _B ≧ V _S , it is determined that the starter motor 12 is not cranking (for example, when an auxiliary load is inserted) because the battery voltage does not drop significantly,
Proceed to P _2. When V _B <V _S , it can be determined that cranking is actually performed, so the start flag ST is set to [1] at P ₄ .

As described above, the cranking state is determined only when the logical product of the two conditions that the battery voltage V _B is lower than the determination level V _S is satisfied in the input state of the start signal. Therefore, the start flag ST is not set when the normal series of procedures are not performed at the time of starting, for example, when the clutch is left unengaged by operating only the ignition key switch 14. As a result, the true cranking state due to the operation of the starter motor 12 can be determined without error, and the detection accuracy of the starting state can be significantly improved. The electronic control of the engine can be surely performed by such highly accurate start information. For example, it is possible to make an appropriate increase in the amount of fuel to start and avoid continuation of unnecessary increase correction. Even in the conventional example shown in FIG. 6, if the present invention is applied, the cranking is determined by the logical product of the two as described above, and therefore the starting state can be determined without error.

FIG. 4 is a diagram showing a second embodiment of the present invention, which is an example of application to a vehicle with an automatic transmission. In the second embodiment, an inhibitor relay 31 is used instead of the start relay, and a neutral parking switch 32 is used instead of the clutch switch. The contact of the neutral parking switch 32 is turned on only when the gear position of the transmission is in the neutral or parking position, and the inhibitor relay 31 is energized only at this time. Others are the same as those in the first embodiment. Therefore, also in the second embodiment, the same effect as in the first embodiment can be obtained.

(Effect) According to the present invention, attention is paid to the temporary decrease in the battery voltage at the time of engine start, and not only the operation of the starter switch but also the state of the battery voltage is detected. As described above, it is possible to provide a starting state detection device having much higher determination accuracy than that of a device that detects only the operation of the starter switch.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram of the present invention, FIGS. 2 and 3 are diagrams showing a first embodiment of an engine starting state detecting device according to the present invention, FIG. 2 is an overall configuration diagram thereof, and FIG. Is a flow chart showing a program for detecting the starting state, FIG. 4 is an overall configuration diagram showing a second embodiment of the present invention, and FIGS. 5 to 7 are diagrams showing a conventional engine starting state detecting device. 5
FIG. 7 is an overall configuration diagram of the first example, FIG. 6 is an overall configuration diagram of the second example, and FIG. 7 is a graph showing the level of a start signal for explaining the operation. 11 ... Battery, 14 ... Ignition key switch (start signal generating means), {16 ... EGI relay, 22 ...
… Microcomputer} (voltage detection means), 19 …… starter motor, 21 …… start relay, 22 …… microcomputer (discrimination means, storage means).

Claims (1)

[Scope of utility model registration request] 1. A start signal generating means for outputting a start signal when a starter motor is being started, b) a voltage detecting means for detecting a power supply voltage supplied to the starter motor, and c) a start. A determination unit that determines the starting state of the engine when the start signal is output from the signal generation unit and the power supply voltage detected by the voltage detection unit falls below a predetermined value; and d) the engine that is determined by the determination unit. A starting state detection device for an engine, comprising: a storage unit that stores the starting state of the engine.