JP2689645B2 - Internal combustion engine start control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine used as a power source for a heat pump or the like, and more particularly to a start control device for automatically starting the internal combustion engine. is there.

[Prior Art] Conventionally, as a start control device for an internal combustion engine (hereinafter referred to as an engine), there is one described in, for example, Japanese Patent Laid-Open No. 59-29951. As shown in FIG. 11, this starting control device performs a TDST cranking for a predetermined time by a starting motor (hereinafter referred to as a starter), and the engine rotation speed is preset as shown by a phantom line. When it reaches, the starter is stopped because the start is completed and idling continues. If the engine speed does not reach the start completion speed α during cranking as indicated by the solid line, stop the starter once because idling does not continue, and restart the starter automatically after the lapse of a predetermined time KST. Perform cranking. Even if the cranking is tried a predetermined number of times, if the engine rotation speed does not reach the start completion rotation speed α, it is determined that the engine cannot be started and the starting operation is stopped.

[Problems to be Solved by the Invention] However, in the above-described starting control device, the completion of starting is determined only based on whether or not the engine speed reaches the starting completion speed α. As a result, when there is a large amount of friction loss in the engine at extremely low temperatures, as shown in Fig. 11, even if the engine itself can be started, the engine rotation speed will increase due to the large friction loss.
There is a problem that the engine cannot be operated because the NE is low and the starting completion rotation speed α is not reached, and it is determined that the engine cannot be started after the cranking is tried a predetermined number of times.

Also, in the above case, the engine during idling will be cranked by the starter,
On the contrary, the starter is driven by the engine, and an excessive load is applied to the starter.

An object of the present invention is to provide a start control device for an internal combustion engine, which can prevent the engine from being inoperable by always performing an appropriate start determination, and can prevent a failure due to a starter injection after the start is completed. To provide.

[Means for Solving the Problems] The present invention, as shown in FIG. 1, includes a starting motor M1 for cranking an internal combustion engine, a rotational speed detecting means M2 for detecting a rotational speed of the internal combustion engine, and the starting motor. The engine is cranked by the motor M1, and when the engine rotation speed detected by the rotation speed detection means M2 reaches a preset start-up completion rotation speed, the start-up motor M1 is determined to have been started. When the engine rotation speed is stopped and the engine rotation speed does not reach the start completion rotation speed, the internal combustion engine is composed of a start control means M3 that temporarily stops the start motor M1 and causes the start motor M1 to crank the engine again after a predetermined time. In the engine start control device, the engine rotation speed detected by the rotation speed detection means M2 is a stall rotation speed set to a value lower than the start completion rotation speed. By the following, the stall determination means M4 for determining that the internal combustion engine has stopped idling operation cannot be continued,
After the engine rotation speed does not reach the start completion rotation speed and the start control means M3 temporarily stops the starting motor M1, and if the stall is not judged by the judgment means M4 for a predetermined time or more, the start is started. The gist is a start control device for an internal combustion engine, which includes a start completion determination unit M5 that prohibits re-cranking by the start control unit M3 when it is completed.

[Operation] When the state in which the stall determination means M4 determines that the stall has not occurred continues for a predetermined time or longer, the start completion determination means M5 determines that the rotation speed of the internal combustion engine has not reached the start completion determination speed but is in the stall state. However, it is determined that the idling rotation speed is kept low due to the rotation speed, that is, the friction loss or the like generated at an extremely low temperature even though the internal combustion engine is in the started state. Then, the start completion judging means M5 prohibits the re-cranking by the start control means M3.

[Embodiment] FIG. 2 is a block diagram showing an electrical configuration of a start control device of the present embodiment. The controller 1 is synchronized with rotation of a water temperature sensor 2 for detecting a cooling water temperature of an engine and a crankshaft of the engine. A detection signal from a rotation angle sensor 3 as a rotation speed detecting means for outputting a signal is input. And
The controller 1 creates an ignition signal based on the both detection signals, and outputs the ignition signal to the ignition coil 4 for igniting the ignition plug of the engine. Further, the controller 1 creates a fuel valve drive signal based on the both detection signals, and outputs the fuel valve drive signal to the fuel valve 5 which supplies fuel into the intake pipe of the engine. Here, the fuel valve 5 is a valve that connects and disconnects the gas supplied to the gas mixer in the gas engine. It is also a valve for intermittently supplying gasoline to the carburetor in the carburetor type gasoline engine. Further, the controller 1 creates a starter drive signal and outputs it to a starter 6 as a starting motor for cranking the engine.

A map shown in FIG. 3 is stored in the controller 1, and the starter drive target time TDST is calculated from the cooling water temperature THW detected by the water temperature sensor 2 based on this map. As shown in this map, the starter drive target time TDST is set to be long and the cranking is performed for a long time at low temperatures where the startability is poor.

Next, the control for starting the engine executed by the controller 1 will be described with reference to the flowcharts of FIGS. 4 and 5. Incidentally, FIG. 4 shows a flow chart of a 5 ms routine executed every 5 ms, and FIG. 5 shows a flow chart of a starter drive routine executed every 40 ms based on the judgment result in the 5 ms routine.

First, the 5 ms routine of FIG. 4 will be explained. Step 1
In 1, the engine cooling water temperature THW (warm-up state) is determined based on the detection signal from the water temperature sensor 2, and in step 12, the starter drive target time TDST is calculated from the cooling water temperature THW from the map shown in FIG. . Next, in step 13, the latest engine rotation speed NE is read based on the detection signal from the rotation angle sensor 3, and in step 14, whether the engine rotation speed NE exceeds a preset completion rotation speed α. Determine whether or not.

When the rotation speed NE exceeds the start completion rotation speed α, it is determined that the start completion is determined, the stall counter CSTAL is cleared in step 15, the starter drive time counter CDST is cleared in step 16, and the start drive time counter CDST is cleared in step 17. Reset the starter drive flag XDST.

On the other hand, when the engine rotational speed NE is equal to or lower than the start completion rotational speed α in step 14, the rotational speed NE is determined in step 18 by the stall determination rotational speed β obtained in advance by an experiment.
It is determined whether (<α) or less (whether the engine is stalled). When the engine speed NE is less than or equal to the stall determination speed β, it is determined that the engine is stalled and the starter drive flag is determined in step 19.
Set XDTS.

When the rotational speed NE exceeds the stall determination rotational speed β in step 18, the starter stop time counter (hereinafter referred to as stop elapsed time counter) CTIM is preset in step 20 assuming that the engine is not stalled. Starter stop time (hereinafter referred to as reference elapsed time) KST
It is determined whether or not it is larger, that is, whether or not the reference elapsed time KST has elapsed since the starter 6 was stopped.

If the reference elapsed time KST has not elapsed since the starter 6 was stopped in step 20 (CTIM ≦ KST), no action is taken and the process returns to step 11. Further, when the reference elapsed time KST has elapsed since the starter 6 was stopped (CTIM> KST), the engine speed NE has not reached the start completion rotation speed α, but the engine is starting, that is, the starter 6 Although the engine has stopped, it is judged that the engine has started idling even after the standard elapsed time KST has elapsed and the engine has been started. Then, in step 15, the stall counter CS
Clear TAL, clear the starter drive time counter CDST in step 16, and starter drive flag XD in step 17.
Reset ST.

Next, the starter drive routine shown in FIG. 5 will be described.

When the starter drive routine is executed to start the engine, it is first determined in step 100 whether the stall counter CSTAL that counts the number of times the starter 6 is driven has exceeded a predetermined number (N times). Since the starter 6 is just before being driven, it is determined that the stall counter CSTAL is equal to or less than N times. In step 101, it is determined whether or not the starter drive flag XDST described in the 5 ms routine is set. At this time, since the engine is just before starting, in step 18 of the 5 ms routine, the starter drive flag XDST is set assuming that the engine rotation speed NE is the stall determination rotation speed β or less.

Therefore, the routine proceeds to step 102, where the starter drive time counter CDST is incremented, and at step 103, whether or not the starter drive time counter CDST exceeds the starter drive target time TDST calculated at step 12 of the 5 ms routine (starter). It is determined whether or not the starter drive target time TDST has elapsed since the start of driving 6). Since the starter driving target time TDST has not elapsed since the starter 6 has not been driven yet, in step 104 the starter 6 is driven and cranking is started.

Further, at step 105, the stop elapsed time counter CTI
After clearing M, the process returns to step 100, and the processes from step 100 to step 105 are repeated again to continue cranking. At the same time, the starter drive time counter CDST is sequentially incremented in step 102, and the count value is compared with the starter drive target time TDST in step 103.

Since the starter drive target time TDST is set to be long when the cooling water temperature THW is low as described above, the startability is improved by performing the cranking for a long time at a low temperature.

Before the starter drive time counter CDST exceeds the starter drive target time TDST, it is determined in step 14 of the 5 ms routine that the engine speed NE has exceeded α (started normally) and the starter drive flag XDST is reset. Then, the starter drive flag XDST is determined not to be set in step 101, the starter 6 is stopped in step 106, and the stop elapsed time counter CTIM described in the 5 ms routine is incremented in step 107. further,
Stop elapsed time counter CT in step 108 and step 109
After performing the IM upper limit guard (FF guard in hexadecimal number), the process returns to step 100.

When the start is completed within the starter target drive time TDST after starting the cranking in this way, as shown in the timing chart of FIG.
The starter 6 is stopped when the rotation speed exceeds the start completion rotation speed α, and the cranking is not performed thereafter. At room temperature, the engine speed NE exceeds the start completion speed α immediately after the engine is started. At this time, therefore, the processes are performed in the order described above.

Meanwhile, in step 103, the starter drive time counter C
DST exceeded the starter drive target time TDST (Starter 6
If the starter drive target time TDST has elapsed since the start of the driving of (1), the stall counter CSTAL is incremented in step 110 because it cannot be started even if the starter 6 is driven. Then, in steps 106 to 109, the starter 6 is stopped and the elapsed stop time counter CTIM is set.
And the upper limit guard of the elapsed stop time counter CTIM are performed, and the process returns to step 100. And step 1
The processing from 00 to step 103, step 110, and step 106 to step 109 is repeated, and the stop state of the starter 6 is maintained.

As described above, after the starter 6 has stopped, the engine speed NE does not exceed the stall determination rotation speed β in steps 18 and 20 of the 5 ms routine, and the reference elapsed time is reached.
When it is determined that KST has elapsed, the starter drive time counter CDST is cleared in step 16. Therefore, in step 103 of the starter driving routine, the starter driving time counter CDST is determined to be equal to or less than the starter driving target time TDST, the starter 6 is driven again in step 104, and the stop elapsed time counter CTIM is cleared in step 105. Then, the processing from step 100 to step 105 is repeated again and the cranking is continued.

The stall counter CSTAL is incremented every time the starter drive target time TDST elapses (the start is not completed even if the starter 6 is driven), and when it is determined in step 100 that the count value exceeds N times,
It is determined that the engine cannot be started even if the engine is started N times, and the engine cannot be started. Then, in step 111, the starter 6 is stopped, in step 102 ignition by the ignition coil 4 is stopped, and in step 113, fuel supply by the fuel valve 5 is stopped.

In this way, the engine speed NE is the start completion speed α
When the starter 6 is stopped for the following reasons, as shown in the timing chart of FIG. 8, when the engine speed NE becomes equal to or lower than the stall determination rotation speed β within the reference elapsed time KST after the starter 6 is stopped, it is started. If not, the stall is judged and the cranking is performed again. further,
Even if this operation is repeated N times, if the start is not completed, it is determined that the start is impossible, and the cranking is not performed thereafter.

On the other hand, step 18 and step 20 of the 5ms routine
If it is determined that the engine speed NE exceeds the stall determination rotation speed β even after the reference elapsed time KST has passed,
The starter drive flag is determined in step 17 assuming that the start is completed.
XDST is reset. Therefore, in step 101 of the starter driving routine, it is determined that the starter driving flag XDST is not set, and in step 106 the starter 6 is stopped. In addition, step 107 to step 1 as described above
At 09, the stop elapsed time counter CTIM is incremented and the stop elapsed time counter CTIM is guarded upper limit. And in this case, step 100, step 101, step
The processing from 106 to step 109 is repeatedly executed, and the stopped state of the starter 6 is maintained.

In this way, the engine speed NE is the start completion speed α
Even when the starter 6 is stopped because of the following, as shown in the timing chart of FIG. 7, the engine speed NE is stalling determination rotation speed β even when the reference elapsed time KST has elapsed despite the starter 6 being stopped. Is exceeded,
Although the engine speed NE has decreased due to friction loss or the like, it is considered that the idling operation is continued, and the starter 6 is not driven thereafter. Since the friction loss of the engine is large at the time of low temperature until the warm-up is completed, the processing is performed in the above-described order.

As described above, the engine start control device of the present embodiment determines whether or not the engine stalls because the idling operation cannot be continued based on the detection signal from the rotation angle sensor 3, and the engine rotation during the starter drive is determined. After the speed NE does not reach the start completion rotation speed α and the starter 6 is temporarily stopped, if the stall is not discriminated, the start is completed and the re-cranking is not performed.

Therefore, as shown in FIG. 7, although the engine speed NE has not reached the start completion rotation speed α, the idling speed of the stall determination rotation speed β or higher is maintained even though the starter 6 is temporarily stopped. If so, it is determined that the start is completed, and re-cranking is prohibited. As a result, it is possible to always reliably determine the completion of the engine start regardless of the temperature, and it is possible to prevent the starter 6 from being broken without turning on the starter 6 after the engine is started.

The present invention is not limited to the above embodiment,
For example, in the above embodiment, the start is completed if the stall determination is not made within the stop elapsed time KTS when the engine does not start even when the starter 6 is driven,
The stall may be determined based on the number of pulses of the rotation angle sensor 3 after the stop elapsed time KTS. That is, as shown in FIGS. 9 and 10, the number of pulses output by the rotation angle sensor 3 is counted within a preset completion determination time t after the elapsed stop time KTS is counted, and shown in FIG. As described above, when the number of pulses within the start completion determination time t is equal to or more than the predetermined number, it is determined that the engine is not stalled and the start completion is determined. When the number of pulses is less than the predetermined number as shown in FIG. It may be determined that the engine is stalled because of a start failure.

Further, in the above embodiment, the fuel valve for interrupting the gas to be supplied to the gas mixer or the fuel valve for interrupting the gasoline to be supplied to the carburetor is controlled, but in the fuel injection engine, the fuel for supplying the fuel into the intake pipe is controlled. The present invention can also be applied by controlling the injection valve.

[Effects of the Invention] As described in detail above, according to the internal combustion engine start control device of the present invention, an appropriate start determination is made at all times, including when the engine friction loss is large, such as during extremely low temperatures. In addition to being able to prevent inoperability,
When the engine friction loss is large, it has an excellent effect of preventing a failure due to the starter being put in after the start is completed.

[Brief description of the drawings]

FIG. 1 is a diagram for responding to a claim, FIG. 2 is a block diagram showing an electric configuration of a starting control device of an embodiment, FIG. 3 is a map for determining a starter drive target time, and FIG. FIG. 5 is a flowchart of a starter drive routine for explaining the operation, and FIG. 6 is a starter drive signal and an engine speed when the start completion is determined. 7 is an explanatory view showing the transition of the starter drive signal and the engine rotation speed when the start completion determination is made because the stall is not performed, and FIG. 8 is the stall determination that the start is defective. FIG. 9 is an explanatory diagram showing the transition between the starter drive signal and the engine rotation speed when the engine is started. FIG. 9 shows the starter drive signal when the start completion determination is made by the start control device of another example and the engine drive speed. Fig. 10 is an explanatory diagram showing a transition with a gin rotation speed, Fig. 10 is an explanatory diagram showing a transition between a starter drive signal and an engine rotation speed when a start failure determination is similarly made by a start control device of another example, Fig. 11 FIG. 4 is an explanatory diagram showing a transition between a starter drive signal and an engine rotation speed when the starter is driven by the conventional start control device after completion of starting. M1 is a starting motor, M2 is a rotational speed detecting means, M3 is a starting control means, M4 is a stall judging means, and M5 is a start completion judging means.

Claims (1)

(57) [Claims] 1. A starting motor for cranking an internal combustion engine, a rotational speed detecting means for detecting a rotational speed of the internal combustion engine, the starting motor for cranking the engine, and the rotational speed detecting means. When the engine speed detected by the engine reaches the preset start completion speed, the starter motor is stopped because the start is completed, and when the engine speed does not reach the start completion speed, the starter motor is temporarily stopped. In the internal combustion engine start control device, which includes a start control means for stopping the engine and again for a predetermined time to perform cranking of the engine by the start motor, the engine rotation speed detected by the rotation speed detection means is
A stall determination means for determining that the internal combustion engine has stopped idling operation when the idling operation is stopped due to the stall rotational speed being set to a value lower than the start complete rotational speed, and the engine rotational speed becomes the start complete rotational speed. After the start control means has stopped the starter motor once and the stall is not judged by the judgment means for a predetermined time or more, it is considered that the start is completed and re-cranking by the start control means is performed. A start control device for an internal combustion engine, comprising: a start completion determining means for prohibiting.