JPH11141442A - Engine start control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle engine start control device that can shorten the time required for starting an engine, reduce the consumption of batteries and improve the degree of the freedom in mounting the controller. SOLUTION: A start control device controls the opening of an exhaust valve by a decompression solenoid 10 when starting a four cycle engine and is provided with a crankshaft sensor 14 for detecting the rotation position of a crankshaft 12, a starter motor 18 for driving the rotation of the crankshaft 12 conditional upon the turning of a starter switch 16 on and an igniter 20, which opens the exhaust valve by the solenoid 10 conditional upon the turning of the starter switch 16 on and stops the valve openings by the solenoid 10 on condition that a specified rotation position is detected by the crankshaft sensor 14 after starting the rotation of the crankshaft 12 by the starter motor 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a start control device for a vehicle engine which opens an exhaust valve with a decompression solenoid when starting cranking by a starter motor of a vehicle such as a motorcycle.

[0002]

2. Description of the Related Art In general, when a starter of a vehicle such as a motorcycle is started, an exhaust valve is opened by a decompression solenoid made of an electromagnetic solenoid to release compression, thereby reducing a load on a starter motor and improving a startability ( A decompression device is also used.

In a conventional start control device, a decompression solenoid controller a controls the decompression solenoid b.
Was controlled by a timer. That is, the start control device operates in the following procedure by the circuit of FIG. 4 according to the flowchart of FIG. And it becomes like the operation time chart of FIG.

First, a decompression solenoid controller a
Turns on the decompression solenoid relay d (step S2) at the same time as the starter switch c is turned on (on) (step S1) on condition that the main switch i and the clutch switch j are turned on (step S2), whereby the decompression solenoid b
To open the exhaust valve.

The controller a turns on the starter relay P and turns on the starter relay P when T ₂ seconds (for example, 0.2 seconds) have elapsed since the decompression solenoid b was turned on by the timer circuit a1. ON
The cranking is performed by the operation of the starter motor g (steps S3 to S5). Then, the decompression T ₁ second after the actuation of the relay d solenoid b (for example 0.7 seconds) to OFF decompression solenoid b (OFF) (step S6~
S8). When the engine starts, set the starter switch c to O
FF is performed (steps S9 to S12). In FIG. 4, h1 and h2 are fuses, k is an ignition coil (k1 is a spark plug), m is a microcomputer (microcomputer) m1 and an igniter incorporating a drive transistor m2, n is a crankshaft sensor, and o is a battery. .

As another conventional technique, a starter current and voltage detection circuit is provided inside the controller as described above,
There is a method in which the necessity of driving the solenoid (whether it is necessary to release the compression) is determined by comparing the value with a preset value to stop useless operation (for example, see Japanese Patent Application Laid-Open No. 1-178767). .

[0007]

In the above prior art,
While the decompression is activated by the solenoid (within the time set by the timer), the engine cannot be started because the exhaust valve is open. I want to close the exhaust valve after the top dead center once. However, since the initial crank stop position varies, it is impossible to uniquely determine the time from the starter motor ON to overcoming the compression top dead center with a timer, and a long timer setting is absolutely necessary. Was. Therefore, conventionally, it took a long time from turning on the starter switch to actually starting the engine. In addition, since the starter motor rotates for a long time, battery power is consumed quickly.

Further, since the apparatus has a decompression controller provided with a timer separately from the ignition device, the circuit configuration is complicated and the cost is increased. In addition, there is a problem that a space for mounting the timer controller is required on the vehicle body layout, which hinders the freedom of the mounting layout inside the vehicle body.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems.
An object of the present invention is to provide a vehicle engine start control device that can reduce battery consumption and increase the degree of freedom in mounting a controller.

[0010]

The present invention has the following configuration to achieve the above object. The invention of claim 1 is
A starting control device that controls the opening of an exhaust valve by a decompression solenoid when starting a four-cycle engine, a crankshaft sensor that detects the rotational position of the crankshaft, and a starter motor that rotates the crankshaft on condition that a starter switch is ON. Opening the exhaust valve by the solenoid under the condition that the starter switch is ON, and
An engine for a vehicle, comprising: a solenoid control unit that stops a valve opening operation by the solenoid on condition that a predetermined rotation position is detected by the crankshaft sensor after the crankshaft starts rotating by a starter motor. Is a start control device. The invention according to claim 2 is the vehicle engine starting device according to claim 1, wherein the solenoid control unit is built in the igniter.

According to the first aspect of the present invention, in the solenoid control section, the exhaust valve is opened by the solenoid coil on condition that the starter switch is turned on, so that the load at the time of starting is released and cranking by the starter motor is performed. This makes it easy to enhance the startability. Then, after the crankshaft is started to rotate by the starter motor, the valve opening operation by the solenoid coil is stopped on condition that the predetermined rotation position is detected by the crankshaft sensor. Therefore, the decompression operation can be stopped.

That is, the exhaust valve is open while the decompression is being operated by the solenoid, and it is sufficient for the decompression to open the valve when overcoming the first compression top dead center. Therefore, according to the present invention, combustion can be started by accurately detecting that the crankshaft has exceeded a predetermined rotational position, for example, once over the compression top dead center, and thereafter closing the exhaust valve. . On the other hand, if the decompression control is performed by the timer as in the conventional technology, the initial crank stop position varies, and the time from the starter motor ON to overcoming the compression top dead center is uniquely determined by the timer. Is impossible, so it was absolutely necessary to set a long timer, it took time until the engine started, but in the present invention, instead of a timer,
Since the decompression can be executed by using the crankshaft sensor accurately corresponding to the rotational position of the crankshaft, the time from turning on the starter switch to actually starting the engine can be reduced. Incidentally, as in the second aspect of the present invention, if the solenoid control unit is built in the igniter, the space efficiency is improved.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 are explanatory diagrams of a vehicle engine start control device according to this embodiment. The engine can be used in a well-known four-stroke engine having an intake valve and an exhaust valve.

As shown in FIG. 1, a start control device controls the opening of an exhaust valve by a decompression solenoid 10 when starting a four-cycle engine.
2, a starter motor 18 for rotating the crankshaft 12 on condition that the starter switch 16 is ON, and a starter switch 16
After the exhaust valve is opened by the solenoid 10 and the crankshaft 12 starts to rotate by the starter motor 18, the crankshaft sensor 14
An igniter (corresponding to a solenoid control unit) 20 for stopping the valve opening operation by the solenoid on condition that a predetermined rotational position is detected by the solenoid.

The igniter 20 uses the input from the crankshaft sensor 14 for calculating the ignition timing. The position of the compression top dead center or the exhaust top dead center of the crankshaft 12 can be detected by the crankshaft sensor 14. As shown in FIG. 1, the igniter 20 has a microcomputer (microcomputer) 20a as a central processing unit. The microcomputer 20a receives the detection signal of the crankshaft sensor 14 and the ON signal of the starter switch 16 and inputs the signal to the microcomputer 20a. 20a to each drive transistor 2
0b, 20c, and 20d through the ignition coil 2
2, a decompression output to the decompression relay 24, and a drive signal output of the starter motor 18 to the starter motor relay 26.
That is, the igniter 20 has a solenoid control unit built therein.

The starting control device includes a battery 28.
, Power is supplied to the microcomputer 20a via the main switch 32 and the fuse 30a, and a clutch switch 34 is connected in series to the starter switch 16 via another fuse 30b. Is turned on, a starter signal is input. Although not shown, an appropriate voltage is applied from a battery 28 to a contact primary side between the decompression relay 24 and the starter motor relay 26.

In the start control device having the above configuration, the microcomputer 20 stores a program for executing the procedure (steps S21 to S37) shown in the flowchart of FIG. Of course, a logic circuit that can execute the same function and order can be employed. FIG. 3 shows the signal waveforms of the respective parts resulting from the execution of this procedure.

First, when the ON state of the starter switch is detected (step S21), the decompression relay 24 is turned on without a short time to drive the decompression solenoid 10 (step S22). If T seconds have elapsed (step S23: YES), the starter motor relay 26 is turned on, and the crankshaft is driven by the starter motor 18 (step S24). As described above, the starter motor 18 is driven after a lapse of T seconds after the start of the driving of the decompression solenoid 10, and the T seconds is such that the power supply voltage is reduced when the decompression solenoid 10 and the starter relay 26 are simultaneously turned on. This is a time difference intentionally provided to prevent the drop. Be sure to turn on the starter motor relay 26 at a time T after turning on the decompression solenoid 10.
N.

Here, before the T seconds have passed, the decompression solenoid 10 is driven as long as the starter switch is kept ON (step S23: NO, step S25: Y).
ES). On the other hand, if the starter switch 16 is turned off before T seconds have passed (step S25: NO), the control is terminated, and the process waits until the starter switch 16 is turned on next.

When the starter motor relay 26 is ON,
The number of pulses detected by the crankshaft sensor (pickup) 14 is counted, and if the number of pulses is the second time (two pulses) (step S26: YES), the decompression relay 24 is turned off and the operation of the decompression solenoid 10 is stopped. (Step S27). At the same time, the starter switch 16 is turned off, and the starter relay is turned off, that is, the starter motor 18 is turned off (step S28). Until the number of pulses reaches the second time, the starter relay 26 is turned on to drive the starter motor (step S29).

Since the decompression only needs to be effective when overcoming the first compression top dead center, as shown in steps S26 to S28, the second time after the starter switch 16 is turned ON (the first When the signal of the crankshaft sensor comes in, the decompression solenoid 10 is turned on.
Set to FF. As a result, the starter switch 16 is turned on.
After that, the time from when the engine is actually started can be reduced.

In the above embodiment, in the igniter 20 for performing the decompression solenoid control, the starter switch 1
The exhaust valve is opened by the decompression solenoid 10 on condition of ON of 6, so that the load at the time of starting can be released, the cranking by the starter motor 18 can be facilitated, and the startability can be improved. Then, the starter motor 18
Then, after the crankshaft 12 starts rotating, the second compression top dead center position is detected by the crankshaft sensor 14 (the first time may not be the first time because the exhaust top dead center may be the first time, but the second time). ), The valve opening operation by the solenoid 10 is stopped, so that the decompression operation can be stopped according to the rotational position of the crankshaft 12.

That is, the exhaust valve is open while the decompression is operated by the decompression solenoid 10, and the decompression only needs to be opened when the vehicle passes over the first compression top dead center after the crankshaft starts rotating. In the embodiment, the decompression is executed not in accordance with the control of the decompression solenoid by the timer but in accordance with the rotational position of the crankshaft 12 (the first top dead center of the certainty) using the crankshaft sensor 14. 16 to O
The time from N to the actual start of the engine can be reduced.

Further, since the starter motor 18 does not need to be rotated for a long time, the consumption of the battery 28 can be reduced. In addition, a dedicated controller for the solenoid is not required, and since the solenoid is integrated with the igniter, the cost is reduced, and the degree of freedom of layout and mounting of the controller on the vehicle body can be increased.

Here, conventionally, when the starter switch is pressed while the engine is running at the idling speed, the decompression operation is performed, and there is a risk of engine stall. Therefore, the present invention further provides a rotational speed N (rp)
m) Once the above is detected, a function for inhibiting the decompression solenoid and the starter relay can be added to prevent engine stall.

[0026]

As described above, according to the first aspect of the present invention, the engine start time can be shortened. Further, since the starter motor does not need to be rotated for a long time, battery consumption can be reduced. Also, as in the invention of claim 2,
A dedicated controller for the solenoid can be integrated into the igniter, thereby reducing costs and increasing the degree of freedom in laying out and mounting the controller on the vehicle body.

[Brief description of the drawings]

FIG. 1 is an explanatory circuit diagram of a start control device for a vehicle engine according to an embodiment of the present invention.

FIG. 2 is an operation flowchart of the start control device of FIG. 1;

FIG. 3 is an operation timing chart of the start control device of FIG. 1;

FIG. 4 is an explanatory circuit diagram of a conventional vehicle engine start control device.

FIG. 5 is an operation flowchart of the start control device of FIG. 4;

FIG. 6 is an operation timing chart of the start control device of FIG. 4;

[Explanation of symbols]

 Reference Signs List 10 decompression solenoid 12 crankshaft 14 crankshaft sensor 16 starter switch 18 starter motor 20 igniter 20a microcomputer 24 decompression relay 26 starter relay 28 battery

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02N 17/08 F02N 17/08 C

Claims (2)

[Claims] 1. A start control device for controlling the opening of an exhaust valve by a decompression solenoid when starting an engine, wherein the crankshaft sensor detects a rotational position of the crankshaft, and the crankshaft is rotationally driven on condition that a starter switch is turned on. A starter motor to be operated, an exhaust valve is opened by the solenoid on condition that a starter switch is turned on, and a predetermined rotation position is detected by the crankshaft sensor after the crankshaft starts rotating by the starter motor. A start control device for a vehicle engine, comprising: a solenoid control unit that stops a valve opening operation by the solenoid under a condition. 2. The start control device for a vehicle engine according to claim 1, wherein the solenoid control unit is integrally incorporated in the igniter.