JPH0491369A - Engine control device - Google Patents

Abstract

PURPOSE:To prevent burning of a starter motor and damage or the like of a starting torque transmitting system by invalidating starting operation of an engine, in at least one of the conditions when an engine speed and an engine temperature are in a predetermined value or more or when power supply voltage is in a predetermined value or less. CONSTITUTION:When an ignition switch 50 is operated in a start position without becoming aware of an engine in rotation, an auxiliary relay 25 is not actuated to invalidate starting operation by the ignition switch 50 because a speed N of the engine exceeds a reference speed N deg., in a CPU12. When the ignition switch 50 is operated in a start position in a condition that battery voltage not reaches reference voltage, the starting operation is similarly invalidated because a battery capacity is only uselessly consumed. Further, when the ignition switch 50 is placed in a start position in a condition that a cooling water temperature of the engine exceeds a reference temperature, the starting operation is similarly invalidated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control system for a starter motor of an internal combustion engine, and particularly to an engine control device suitable for an automobile gasoline engine.

[Conventional technology]

In general, internal combustion engines have difficulty in self-starting, and their rotating shaft must be rotated by some means to reach a certain rotational speed.For this reason, for example, automobile engines are equipped with a starter motor powered by a battery. is customary.

By the way, control of the starter motor used to depend solely on the operation of the ignition switch (key switch) by humans, but in recent years, other factors have been Various proposals for control that take into account the
No. 8964, JP-A-61-142363, JP-A-62
It can be found in each publication of No. 48961.

[Problem that the invention seeks to solve]

The above conventional technology does not take into consideration the conditions under which the starter motor can be operated, and when the ignition switch is operated, the starter motor is always activated, resulting in damage to the starting torque transmission system including the starter motor. In addition, there have been problems such as over-discharging of the battery, which is the energy source for driving the starter motor, and so-called dead battery.

The present invention reliably limits the start of rotation of the starter motor to only when the conditions for that purpose are satisfied, and sufficiently suppresses the risk of damage to the starter motor or the starting torque transmission system, abnormality, and dead battery. The purpose is to provide an engine control device with

[Means to solve the problem]

The above purpose is to switch the ignition switch when the engine speed is above a predetermined value, when the engine temperature is above a predetermined value, or when the voltage of the starter motor power source is below a predetermined value. This is achieved by disabling the engine starting operation.

[Effect]

When the engine speed is above a predetermined value, it means that the engine itself is generating torque, and when the engine temperature is above a predetermined value, it means that the starter motor is in a high temperature state, and the starter motor's power source is in a high temperature state. When the voltage is below a predetermined value, it indicates that the battery is nearing the end of discharge, but at these times, the starting operation by the ignition switch is disabled, so there is a risk of burnout of the starter motor or a reduction in the starting torque. Damage to the transmission system, abnormalities, and dead batteries are unlikely to occur.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An engine control device according to the present invention will be explained in detail below using illustrated embodiments.

FIG. 1 shows an embodiment of the present invention. In the figure, 10 is a control circuit for engine control, a CPU 12, a ROM
14, RAM 16, backup RAM 17, and an input/output interface circuit 18.

The CPU 12 connects the starter contact 50A of the ignition switch 50 via the input/output interface circuit 18.
and various sensors such as the cooling water temperature sensor 60, crank angle sensor 70.02 sensor 80. Signals from the load sensor 90, load switch 100, etc. are taken in, stored in the ROMI 4, and arithmetic processing is performed using various data necessary for engine control, such as fixed data such as ignition timing and fuel injection control program. A control signal is created and supplied to an ignition coil, fuel injection valve, etc. (not shown) via the input/output interface circuit 18, and control is performed to obtain the required engine operating state. do. At this time, the RAM 16 is used to temporarily store calculation results and control data, and the backup RAM 17 is used to store data that needs to be retained even when the engine is stopped.

Note that a control circuit including such a CPU for engine control is well known, so a detailed explanation will be omitted.

Next, 20 is a starter motor, as shown in Figure 2,
It consists of an armature 20A, a shaft 20B1, a pinion 20C movably held on the shaft 20B as shown by a broken line, and is further provided with a solenoid relay 30.

When current is supplied to this relay 30, the plunger 30A is attracted against the displacement force of the torsion spring 30B, and as a result, the shift lever 30
Binion C is pushed out to the position indicated by the broken line via G, meshes with the ring gear of the engine, and starts this starter motor 2.
0 transmission of starting torque is possible.

Further, this solenoid relay 30 is further provided with a contact 30D that is closed by suction movement of the plunger 30A, and when this contact 30D is closed,
As is clear from FIG. 1, the configuration is such that current is supplied to the starter motor 20 from a power source (battery) having a voltage VB. Returning to FIG. 1, 25 is an auxiliary relay;
It is equipped with a coil 25A and a normally open (NC) contact 25B, the coil 25A is connected between the line to which the inhibit signal I/H is supplied and the collector of the transistor 19, and the contact 25B is connected to the starter contact 50A of the ignition switch 50. and the electromagnetic coil 30E of the solenoid relay 30. The base of the transistor 19 is supplied with the control signal S from the input/output interface circuit 18, so that the auxiliary relay 25 receives both the inhibit signal I/H and the control signal S at II HI+. It is configured to operate and close one contact 25B only when the level is reached.

First, let us explain about the inhibit signal I/H. This signal I/H is activated only when the selector lever of the automatic transmission is in the P (parking) position.
It is a signal that becomes level. Incidentally, an engine control device as shown in FIG. 7, which is equipped with such an inhibit signal I/H and an auxiliary relay 25, is known, and in such a conventional example, the selector lever of the automatic transmission is When the ignition switch 50 is not operated to the (parking) position, even if the ignition switch 50 is operated to the starter position, the drive control of the starter motor 20 is disabled, thereby ensuring safety. be.

Therefore, in this embodiment, as described above, the transistor 19 is provided, and the control signal S is supplied to it from the input/output interface circuit 18, and as a result, as described above, the transistor 19 is provided. In this case, the auxiliary relay 25 outputs both the inhibit signal I/H and the control signal S to II H.
The control signal S is configured to operate and close the contact 25B only when the level reaches I+, thereby achieving the object of the present invention. The operation of this embodiment will be explained.

As is clear from FIG. 1, the CPU 12 in the control circuit IO receives and monitors the signal from the ignition switch 50, and when it is operated to the start position, the process shown in FIG. 3 is started.

That is, when the starter contact 50A of the ignition switch 50 is closed, the processing by the CPU 12 jumps to step 200 in FIG.
After setting the level to "L I+ level," step 202 is performed sequentially.
, step 203, and step 204.

Then, each of these judgment processing steps 202, 203.
Only when all the results in step 204 are N (negative) does the process proceed to step 205, and only then is the signal S set to IIH.
“Level it up.

After that, in processing step 206, a predetermined timer is set, and in the subsequent processing step 207, waiting for the elapse of a predetermined time,
After the time has elapsed, the process returns to step 202.

Therefore, judgment processing step 202, step 203,
If the judgment result is Y (affirmative) in either step 204, the process proceeds to step 208, where the signal S of the input/output interface circuit 18 is set to II L I+ level, and then the process of FIG. 3 is performed. It ends.

First, in step 202, it is determined whether the engine rotational speed N is greater than or equal to the reference rotational speed N0 shown in FIG. 4, and in the next step 203, the battery voltage
, is equal to or higher than the reference voltage VB6 shown in FIG. 5, and in the subsequent step 204, the engine cooling water temperature T
It is determined whether w is the reference temperature Tw in FIG. 6 or not.

Next, the operation obtained by executing the process shown in FIG. 3 will be explained.

Now, when starting the engine, the automatic transmission selector
Assume that the lever was operated correctly in the P (park) position, the engine was stopped, the battery voltage was at a normal value, and the engine cooling water temperature was not particularly high. .

Then, among the operating conditions of the auxiliary relay 25, the condition that the inhibit signal I/H is at the "H" level is satisfied.

However, even if the ignition switch 50 is operated to the start position, the auxiliary relay 25 does not operate because the signal S is set to II L I+ level in processing step 201 of FIG. 20 does not start rotating for the time being.

However, as mentioned above, at this time the engine is stopped and the battery voltage is at a normal value.
Furthermore, since the engine cooling water temperature is not particularly high, the judgment results in all steps 202, 203, and 204 are N, so the signal S, which was once set to the 71 L 1'' level in processing step 201, is After that, the level is set to "H" in step 205, where the transistor 19 becomes conductive, the auxiliary relay 25 operates, and the starter motor 20 starts rotating.

Then, after a predetermined period of time has elapsed, the process returns to step 202, but if the engine has completely exploded (started) at this time, its rotational speed N should have reached the reference rotational speed N, as a matter of course. Therefore, the judgment result is N, and this result is 1. Proceeding to processing step 208, the current supply to the starter motor 20 is cut off, and the starting operation is automatically stopped.

However, if you operate the ignition switch 50 to the start position without noticing that the engine is rotating, at this time the engine rotational speed N will be lower than the reference rotational speed N shown in FIG. , the result in processing step 202 is Y, and as a result, the start operation by the ignition switch 50 is invalidated, which would be caused by operating the starter motor 20 while the engine is rotating. It is possible to prevent failures and abnormalities in the starting torque transmission system, such as gear tooth chipping.

Next, without noticing that the battery voltage V8 has not reached the reference voltage V□, the ignition switch 5
0 to the start position, at this time, as shown in Fig. 5, even if the starter motor 2
Even if the current is applied to 0, as shown in Fig. 5, the torque necessary to rotate the engine cannot be obtained, and the battery capacity will be wasted unnecessarily. At this time, step 20
Since the determination result in step 3 is Y, the operating conditions of the starter motor 20 are not satisfied, the start operation is disabled, and it is possible to prevent the battery from running out.

Furthermore, if you operate the ignition switch 50 to the start position without noticing that the engine cooling water temperature Tw exceeds the reference temperature Tw,
At this time, the temperature of the starter motor 20 is also high, so if the starter motor 20 is energized and operated as it is, the operating temperature will exceed the rated value and there is a risk of torque reduction and seizure. As shown in the figure, the operating time has to be shortened and engine starting becomes impossible. If the condition is not satisfied, the start operation is disabled, and the occurrence of an abnormality can be prevented.

Therefore, according to this embodiment, based on the relationship between the engine rotation speed N, the battery voltage VB, the cooling water temperature Tw, and the characteristics of the starter motor 20, the reference rotation speed N is a rotation speed sufficient for determining the complete explosion of the engine. . and the reference voltage VB0, which is the minimum battery voltage required to drive the starter motor.
, and the reference water temperature Tw, which is the temperature at which the starter motor can be used safely, are selected to appropriate values to reduce the gear loss caused by rotating the starter motor after the engine has completely exploded. In addition to suppressing the occurrence of tooth chipping and abnormal noise, the battery drain is also sufficiently suppressed at low temperatures, and furthermore, the rise in temperature of the starter motor at high temperatures is suppressed, reducing its thermal load. It is possible to sufficiently reduce the size and weight of the motor.

In the above embodiments, the present invention is applied to a vehicle equipped with an automatic transmission.
As a result, the inhibit relay provided in such automobiles is commonly used as the auxiliary relay 25.
It goes without saying that an independent relay may be used.

Further, in the above embodiment, the reference rotation speed N there.

, reference voltage VB, and reference water temperature Tw are all fixed values, but since these values are parameters that change depending on various conditions such as engine temperature and battery voltage, they can be set as variables by map search. You may also set it.

Furthermore, in the above embodiment, the temperature of the starter motor is represented by the engine cooling water temperature, which eliminates the need to install a special sensor, but a temperature sensor is installed on the starter motor separately from the cooling water temperature sensor. Needless to say, you can do it this way.

[Effects of the Invention] According to the present invention, it is possible to prevent damage to the starter motor, chipped gear teeth, misalignment of the engine timing belt, generation of unpleasant noises, etc. caused by operating the starter motor while the engine is rotating. , it is possible to obtain sufficient improvements in reliability and safety.

Further, according to the present invention, since the temperature rise of the starter motor can be suppressed, it is possible to reduce the size and weight of the starter motor.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an engine control device according to the present invention, FIG. 2 is a partial sectional view showing an example of a starter motor, and FIG. 3 is a diagram for explaining the operation of an embodiment of the present invention. The flowchart, FIGS. 4, 5, and 6 are characteristic diagrams for explaining the operation, and FIG. 7 is a block diagram of a conventional example. 10... Control circuit, 12...
CPU. 20... Starter motor, 25... Auxiliary relay 30... Solenoid relay, 50...
...Ignition switch. Agent Patent Attorney Takeshi Junji Department (1 other person) Fig. Fig. λ2-? Rotation speed (rpm) Fig. z>-,9%h le>(kg-m) Fig. λ2-> Rotation E4 quality (1)

Claims (1)

[Claims] 1. In an engine control device that controls the rotation of the starter motor in response to the engine starting operation using the ignition switch, data representing the engine rotation speed, data representing the engine temperature, and voltage of the power source of the starter motor are represented. A calculation means that inputs at least one of the data and a relay that prohibits driving of the starter motor by the output of the calculation means are provided, and the relay is configured to operate when the rotational speed of the engine is above a predetermined value and when the temperature of the engine is a predetermined value. or when the voltage of the power source of the starter motor is at least one of the predetermined values or less,
An engine control device characterized in that it is configured to generate an output from the arithmetic means and to disable the engine starting operation by the ignition switch.