JP2003286929A - Engine start determining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely determine start of an engine. <P>SOLUTION: Battery voltage is detected (S1), and engine starting control for fuel injection quantity, ignition timing, etc., adapted for starting is executed (S2). When the battery voltage VB is above a second prescribed voltage value STOFFVBL for the battery voltage VB set higher than a voltage value before drive of the engine, and as it is determined to have experienced a state below a first prescribed voltage value STONVBL lower than a voltage value before start of the engine, the starting control is changed into normal control (S3→S4→S5). When it is determined that it has not experienced a state below the first prescribed voltage value STONVBL, it is judged as the engine has started when engine rotation speed Ne becomes over a prescribed value NSTOFFA, and start determination is stopped, with starting control changed into normal control (S3→S6→S7→S5). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for determining whether the engine is started by a starter motor.

[0002]

2. Description of the Related Art Conventionally, as a technique for making the above-mentioned engine start determination by software, there is a technique in which it is determined that the engine has started when the engine speed exceeds a certain value, and the engine start control is switched to the normal control.

[0003]

However, even when the user wants to stop the starter motor to stop the start determination and shift to the normal control when the speed of increase of the engine speed at the start is slow due to low water temperature or the like. Since the engine rotation speed does not reach the rotation speed at which the start determination is stopped, the engine start control continues, and in the worst case, the fuel injection amount may be excessive, which may result in a spark plug fogging or a start failure.

In the technique disclosed in Japanese Unexamined Patent Publication No. 2000-179394, the start voltage is detected by detecting the battery voltage. For example, when the power is supplied from an external power source to start the battery, the voltage is determined. Since the fluctuation is affected by the external power source, the state of the engine cannot be accurately determined, which may result in a start failure. The present invention has been made in view of such conventional problems, and an object of the present invention is to provide an engine start determination device capable of surely determining engine start by a simple method.

[0005]

Therefore, the invention according to claim 1 is a start determination device for an engine which is started by a starter motor driven by being supplied with electric power from a battery, and which is a voltage for detecting a battery voltage. A second predetermined voltage in which the battery voltage is equal to or higher than the voltage value before the engine is driven after the detection means and the detected battery voltage experience a voltage value that is smaller than the first predetermined voltage that is equal to or lower than the voltage value before the engine is started. When it becomes larger, the voltage start determination means for determining that the engine has started, and the first predetermined value that is equal to or lower than the voltage value before the engine start before the battery voltage becomes equal to or higher than the second predetermined voltage value. A rotational speed determining means for determining that the engine has started when the engine rotational speed is equal to or higher than a predetermined rotational speed when the engine does not experience a value smaller than the voltage. Characterized in that the configuration was.

According to the first aspect of the invention, normally, the start determination can be made only by the battery voltage, so that the engine start can be determined even in the cold state with a simple structure, and the engine start control can be appropriately performed. The start can be determined even when the engine is started using an external power source, as well as can be ended in a period.

For example, when the rated voltage of the battery is 12 [V] as in the inventions according to claims 2 and 3, the first
Is set to 11 [V] and the second predetermined voltage is set to 13.
It may be 5 [V]. The invention according to claim 4 is
A start determination device for an engine that is started by a starter motor that is driven by being supplied with electric power from a battery, and is a start determination device for an engine that is started by a starter motor that is supplied with power from a battery and is driven by a battery voltage. And the detected battery voltage is decreased by a first predetermined amount from the voltage value before the engine is started, and then the battery voltage is increased by a second predetermined amount from the voltage value before the engine is driven. In this case, the voltage start determination means for determining that the engine has started and the first voltage value before the engine start before the battery voltage rises by a second predetermined amount from the voltage value before the engine drive. If the voltage has not dropped by a predetermined amount, the rotation speed that determines that the engine has started when the engine rotation speed is equal to or higher than the predetermined rotation speed. Characterized by being configured to include a judgment means.

The invention according to claim 4 has the same effect as that of the invention according to claim 1, and in the case where the absolute value of the battery voltage (voltage value before the engine is driven) changes due to environmental changes. Also, the engine start can be reliably determined using the variation amount.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the system configuration of an engine start determination device according to an embodiment of the present invention. The starter motor 2 for starting the engine 1 is driven when the key switch 5 connected to the battery 3 via the relay 4 is set to the start position. A crank angle sensor 6 for detecting the engine rotation speed Ne is provided, and an engine rotation speed signal Ne from the crank angle sensor 6 is input to a control unit 7 for engine control together with the battery voltage signal VB and the like.

The control unit 7 determines whether the engine is started (start is completed) based on the engine speed Ne and the battery voltage VB. In the conventional determination method in which the start determination is stopped when the engine rotation speed Ne becomes a certain value or more and the control is shifted to the normal control, for example, when the engine friction torque is large under the low water temperature condition, When the rising speed is slow, even if the user of the vehicle wants to stop the starter motor and stop the start determination, it takes time until the engine rotation speed Ne reaches the above-mentioned constant value, so that the start determination stop is delayed. As a result, the fuel is injected excessively in response to the request, which may cause a start failure due to plug fogging or overrich.

Therefore, in the present invention, in order to prevent the above situation, the start control based on the behavior of the battery voltage (terminal voltage) and the start determination based on the engine rotation speed are used together to terminate the control at the time of start. , Do not perform startup control for an unnecessarily long time. FIG. 2 shows a start determination control flow of the engine according to the first embodiment. This routine is started when a start operation is detected by detecting that the key switch 5 is set to the start position.

In step 1, the control of the fuel injection amount, ignition timing, etc. corresponding to the start is performed. In step 2, the battery voltage VB is read. In step 3, it is determined whether the battery voltage VB is equal to or higher than a second predetermined voltage STOFFVBL which is equal to or higher than the voltage value before the engine is driven. Here, the second predetermined voltage STOFFVBL is driven with the starter motor being stopped and the engine being driven after the engine is started (completed) with respect to the voltage value before the engine is driven, that is, in the stopped state where the key switch is turned off. Is set near the voltage value that increases as the rotation speed of the alternator increases. For example, the rated voltage of the battery is 1
When it is 2 [V], it is set to about 13.5 [V].

Then, in step 3, VB ≧ STOFFV
When it is determined to be BL, the process proceeds to step 4, and it is determined whether the battery voltage VB has experienced a state of being equal to or lower than a first predetermined voltage STONVBL which is equal to or lower than a voltage value before engine start. Here, the first predetermined voltage STONVBL is set in the vicinity of a voltage value that decreases due to a sudden increase in the drive current of the starter motor.

When it is determined that the state where the voltage is equal to or lower than the first predetermined voltage STONVBL is experienced, the routine proceeds to step 5, where it is determined that the engine has started, and the start-up control of step 1 is stopped and the normal control is resumed. Switch. That is, the battery voltage drops once due to the sudden increase in the drive current accompanying the starter motor drive, and then the user completes the explosion (starting completion).
When the starter motor is stopped by recognizing the above, the start of the engine can be determined from the characteristic of the battery voltage that the battery voltage recovers due to the rapid decrease in the consumption current and the rapid increase in the generated current.

In step 4, the battery voltage VB is first
When it is determined that the vehicle has not experienced the state of being equal to or lower than the predetermined voltage STONVBL of No. 3, the process proceeds to step 6 to detect the engine rotation speed Ne, and the engine rotation speed Ne is equal to or higher than the set rotation speed NSTOFFA that can determine the start due to complete explosion. It is determined whether or not there is, and when NSTOFFA or more, the start determination is stopped, and the process proceeds to step 5 to switch from the control at startup to the normal control.

FIG. 3 shows changes in the engine speed and the battery voltage at the time of starting when the water temperature is low according to the elapsed time.
I want to stop the start determination at the starter motor stop position and shift to normal control, but in the case of the conventional determination based on only the engine speed, it takes time for the engine speed to rise, so the start determination is stopped. The timing is the timing indicated by "start control stop timing engine rotation speed" in the figure, which is behind the request.

On the other hand, in the start determination based on the battery voltage, which is the basis of the present invention, the timing at which the start determination is stopped because the battery voltage rises at the same time when the starter motor is stopped is indicated by "start control stop timing battery voltage" in the figure. The timing comes, and it almost matches the request. To explain the mechanism of the above in more detail, when the starter motor is normally rotated, the battery voltage drops below the initial voltage, and when the starter motor is stopped, the voltage recovers and becomes higher than the initial state. (See Figure 4). That is, since the power consumption of the starter motor is large, a voltage drop occurs when the starter motor is rotated, so that the voltage drops below the initial voltage, but when the starter motor is stopped, it is not necessary to supply the consumed power, so the voltage is Recover. Also, when the starter motor is stopped and the starter motor is stopped, the engine speed increases and the alternator starts generating power, so the supplied power exceeds the power consumption,
The battery voltage rises to the voltage supplied by the alternator.

Therefore, at the time of normal starting, the voltage value (STOFFVBL) for stopping the start determination is set to be not less than the battery voltage during cranking (black diagonal square in FIG. 4) and less than the voltage supplied by the alternator (black square in FIG. 4). If so, it can be known that the starter motor has stopped. Therefore, if the battery voltage becomes equal to or higher than STOFFVBL, the start control may be stopped.

Further, the alternator supply voltage becomes smaller (larger) as the increase in the rotation speed of the alternator driven by the engine becomes smaller (larger) as the engine water temperature becomes lower (higher) and the engine friction becomes larger (smaller). Become. Therefore, if the voltage value STOFFVBL for stopping the start determination is variably set according to the engine water temperature, the accuracy of the start determination can be improved.

As a situation that can be considered at the time of starting, as shown in FIG. 5, there is a case where electric power is supplied from an external power source 8 other than the vehicle battery to start the vehicle. In this case, the supply voltage increases before the start determination is started and the engine is started. If the supplied electric power is large, it reaches the level at which the start determination is stopped (STOFFVBL in FIG. 5).
There is a possibility that the above-described start determination stop due to the voltage increase is performed before the engine is started, and the engine control shifts from the starting control to the normal control, resulting in a start failure.

In order to prevent this, the battery voltage is continuously monitored as shown in FIG. 6, and when the voltage drop is small (the minimum voltage does not fall below STONVBL), the power supply during cranking is performed from the external power source. 6 and the start determination stop by the voltage shown in FIG. 6 "start control stop timing external power supply" is not performed,
"Starting control control timing" Start determination is stopped at the engine speed, and control is transferred to normal control. That is, the start determination stop by the voltage (“start control stop timing at normal start” in FIG. 6) is performed only when the voltage experiences the constant value STONVBL or less during the start determination.

However, to explain the mechanism as described above in more detail, since the starter motor 2 consumes a large amount of current, a general starting system including the battery 3 and the starter motor 2 has a large voltage drop.
From a market point of view, the voltage during cranking becomes STONVBL or less as shown in FIG. 7 (A). When the vehicle is started by an independent start system, it always drops below this voltage for a moment {Fig. 7 (B) x}. On the other hand, for example, when the battery cannot be started by itself in a discharged state, the external power source 8 supplies power to start the battery as shown in FIG. At this time, the voltage fluctuation at the time of starting is affected by the amount of electric power supplied from the external power supply 8. When the amount of power supply is very large with respect to the amount of power consumption of the starter motor, the voltage drop due to the start-up of the starter motor 2 is small and is affected by the voltage fluctuation of the external power supply 8 rather than the operation of the starter motor 2. If the battery voltage rises by the external power supply 8 before the completion of the engine start, the start determination is stopped even if the engine 1 is not started, so in the worst case, the engine 1 cannot be started (the external power supply voltage is It may be considered that STOFFVBL is exceeded, and in that case, the start determination is stopped at the same time as power is supplied, and normal control is entered, so there is a higher possibility that startup will not be possible).

In such a case, the voltage drop is smaller than when starting by itself. By utilizing this characteristic, the battery voltage is constantly monitored, and when the minimum value of the voltage fluctuation is STONVBL or more, it is determined that power is being supplied from the outside, and the start determination stop by the battery voltage is not performed. That is,
The start determination is stopped by the battery voltage only when the battery voltage during the start determination is reduced to STOVBL or less.

The minimum value of voltage fluctuation is STONVBL
When the above is maintained, the start determination is stopped by the engine speed similar to the conventional one, but the battery voltage is STOF.
Since the start determination stop based on the engine rotation speed is performed under the condition that it is FVBL or more, the start determination stop can be determined more accurately. FIG. 8 shows an engine start determination control flow according to the second embodiment (corresponding to claim 4).

The starting control is performed in step 11, and the battery voltage VB is read in step 12 as in the first embodiment. In step 13, it is determined whether or not the battery voltage VB has increased by a second predetermined amount ΔSTOFFVBL voltage from the voltage value before driving, which was read immediately before driving the engine. This second predetermined amount ΔSTOFFVBL is a voltage value in a stopped state before the engine is driven, that is, when the key switch is OFF, and after the engine is started (completed), the drive of the starter motor is stopped and the alternator of the engine is driven. It is set near the amount of voltage that increases as the rotation speed increases.

Then, in step 13, the second predetermined amount ΔS
When it is determined that the TONVBL voltage has risen, the routine proceeds to step 14, where it is determined whether the battery voltage VB has experienced a voltage drop of a first predetermined amount ΔSTONVBL from the voltage value before engine start. Here, the first predetermined amount ΔS
TONVBL is set in the vicinity of the voltage value that decreases due to a sudden increase in the drive current of the starter motor. Further, the voltage value before the engine start is variably set according to the water temperature, or the deviation between the voltage value before the engine drive and the reference value of the before drive voltage value is obtained, and the deviation is calculated from the reference value of the before start voltage value. It is set variably according to environmental changes, such as setting after subtracting the deviation. Alternatively, the first predetermined amount ΔSTONVBL may be variably set according to the water temperature or the like.

Then, the first predetermined amount voltage ΔSTONVB
If it is determined that L has been decreased, step 15
When it is determined that the engine has started, the process proceeds to step 11 to stop the starting control in step 11 and switch to normal control. Further, in step 14, the battery voltage VB is the first predetermined amount voltage ΔS.
When it is determined that the reduction of the TONVBL has not been experienced, the routine proceeds to step 16, the engine rotation speed Ne is detected, and it is determined whether the engine rotation speed Ne is equal to or higher than a set rotation speed NSTOFFA capable of determining the start due to complete explosion. Then
When NSTOFFA or more, the start judgment is stopped,
The process proceeds to step 15 to switch from the control at startup to the normal control.

In the present embodiment, even if the absolute value of the battery voltage (voltage value before engine driving) changes due to environmental changes, it is possible to reliably determine engine start.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an engine start determination device according to the present invention.

FIG. 2 is a flowchart showing a start determination control routine according to the first embodiment.

FIG. 3 is a time chart showing a start determination based on a battery voltage and a start determination based on an engine rotation speed in comparison.

FIG. 4 is a diagram for explaining a setting condition of a battery voltage (second predetermined voltage value) for start determination in the embodiment.

FIG. 5 is a system configuration diagram when starting by using the external power supply according to the embodiment.

FIG. 6 is a time chart showing how the battery voltage changes at the time of starting according to the above embodiment.

FIG. 7 is a diagram for explaining a setting condition of a battery voltage (first predetermined voltage value) for start determination in the same embodiment.

FIG. 8 is a flowchart showing a start determination control routine according to the first embodiment.

[Explanation of symbols]

1 engine 2 Starter motor 3 battery 5 key switch 6 Crank angle sensor 7 control unit

Claims (4)

[Claims] 1. A start determination device for an engine, which is started by a starter motor driven by being supplied with electric power from a battery, wherein voltage detection means for detecting a battery voltage, and the detected battery voltage are those before starting the engine. After experiencing a voltage value that is less than a first predetermined voltage that is less than or equal to a voltage value, a second voltage value that is greater than or equal to the voltage value before the engine is driven.
Voltage start determination means for determining that the engine has started when the voltage becomes higher than the predetermined voltage, and before the battery voltage becomes equal to or higher than the second predetermined voltage value, When a value smaller than the predetermined voltage of 1 is not experienced, a rotation speed determination unit that determines that the engine has started when the engine rotation speed is equal to or higher than the predetermined rotation speed is included. And an engine start determination device. 2. The engine start determination device according to claim 1, wherein the rated voltage of the battery is 12 [V] and the second predetermined voltage is 13.5 [V]. 3. The engine starting control device according to claim 1, wherein the rated voltage of the battery is 12 [V] and the first predetermined voltage is 11 [V]. 4. A start determination device for an engine that is started by a starter motor that is driven by being supplied with electric power from a battery, and is a start determination device for an engine that is started by a starter motor that is supplied and supplied with power from a battery. A voltage detecting means for detecting a battery voltage, and a battery voltage detected from a voltage value before the engine is driven to a second voltage after the detected battery voltage is lowered by a first predetermined amount from the voltage value before the engine is started. Voltage start determination means for determining that the engine has started when the voltage has risen by a predetermined amount, and a voltage before the engine starts before the battery voltage rises by a second predetermined amount from the voltage value before the engine is driven. If the voltage does not drop by the first predetermined amount from the value, the engine is started when the engine speed becomes equal to or higher than the predetermined speed. An engine start determination device, comprising: a rotation speed determination means for determining.