JP2006057525A - Starter failure detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform accurate diagnosis of a regular ON-failure of a starter without using a voltage detecting circuit for detecting the operated condition of the starter. <P>SOLUTION: The presence or not of the regular ON-failure of a starter is determined depending on whether the condition that there is a probability of the regular On-failure of the starter, namely, the condition that a vehicle speed or an engine speed is a preset value or higher although braking force works at a preset value or more on a travelling road not downsloping is kept on or not for a preset time or longer (S101-104). Herein, whether the braking force is the preset value or more or not can be determined depending on whether the footing amount of a brake pedal detected by a brake pedal footing amount sensor is a preset value or more or not, or whether brake hydraulic pressure detected by a brake hydraulic pressure sensor is a preset value or higher or not. Besides, whether the travelling road is downsloping or not can be determined in accordance with an output signal from an inclination sensor which detects the inclination of the travelling road or a vehicle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a starter failure detection device that detects a failure of a starter that starts an engine.

  In vehicles equipped with an idle stop system that automatically stops idling of the engine while the vehicle is stopped, the number of idle stops increases when driving in urban areas where there are many stops due to traffic lights or traffic jams. The number of times the engine is automatically restarted increases, and accordingly, the failure occurrence rate of the starter is unavoidably increased. In addition, since the control device automatically energizes the starter when restarting after an idle stop, even if the starter itself has not failed, the control device side fails or malfunctions and the starter continues to be energized (hereinafter referred to as the starter). The possibility of the occurrence of “always-on failure” cannot be denied.

Therefore, as shown in Patent Document 1 (Japanese Patent Laid-Open No. 2003-201943), the voltage in the starter drive circuit is detected as a starter operation recognition signal, and the starter operation time determined from the duration of the starter operation recognition signal is predetermined. In some cases, when the time is exceeded and the engine speed exceeds a predetermined value, it is determined that the starter is always on and the safety relay is turned off to cut off the energization of the starter.
JP 2003-201943 A (2nd page to 3rd page, etc.)

  However, in the technique of Patent Document 1, it is necessary to newly add a voltage detection circuit that detects a voltage in the starter driving circuit as a starter operation recognition signal, and there is a problem that the manufacturing cost increases. Moreover, when the voltage detection circuit fails, there is a risk that even if the starter is normal, it is erroneously diagnosed as a starter failure and the starter cannot be started.

  The present invention has been made in consideration of such circumstances, and therefore the object of the present invention is to accurately diagnose a starter always-on failure without providing a voltage detection circuit for detecting the starter operating state. It is an object of the present invention to provide a starter failure detection device capable of satisfying the demands for prevention of erroneous diagnosis of failure and cost reduction.

  In order to achieve the above object, the invention according to claim 1 includes brake force detection means for detecting a brake force, vehicle speed detection means for detecting the vehicle speed, and engine rotation speed detection means for detecting the engine rotation speed. In this system, a state in which the vehicle speed or the engine rotational speed does not decrease according to the braking force continues for a predetermined time or more despite the braking force exceeding a predetermined value based on the detection results of these detection means. In this case, it is diagnosed that a failure in which the starter is constantly energized (hereinafter referred to as “always ON failure”) has occurred.

  In other words, if the braking force is applied during driving, it is normal for the vehicle speed and engine speed to decrease according to the braking force. If the engine rotation speed does not decrease according to the braking force, it can be determined that the drive force of the starter is working against the braking force. Since this state occurs due to the always-on failure of the starter, when this state continues for a predetermined time or longer, the starter is always diagnosed as a failure. In this way, it is possible to accurately diagnose the always-on failure of the starter without providing a voltage detection circuit for detecting the starter operating state as in Patent Document 1, and to prevent misdiagnosis of the always-on failure. it can. In addition, the brake force detection means, vehicle speed detection means, and engine rotation speed detection means used for this failure diagnosis can share various sensors mounted on the vehicle for other control, so that the current vehicle On the other hand, it is possible to mount the failure diagnosis function of the present invention only by changing the software without changing the hardware, and it is possible to satisfy the demand for cost reduction.

  In this case, when traveling downhill, the vehicle speed and the engine rotational speed may not continue to decrease according to the braking force even if the starter always has an ON failure. Whether or not the traveling road is a downhill is determined by the downhill determination means. As a result, when it is determined that the traveling road is a downhill, the failure diagnosis may be prohibited by the failure diagnosis prohibiting means. . In this way, it is possible to prevent erroneous diagnosis of the always-on failure of the starter due to downhill.

  According to a third aspect of the present invention, there is provided an inclination angle sensor for detecting the inclination angle of the traveling road or the inclination angle of the vehicle, and whether or not the traveling road is a downhill based on the inclination angle detected by the inclination angle sensor. May be determined. Thereby, a downhill can be detected with high accuracy.

  Further, as in claim 4, the brake force may be detected based on the output of a sensor that detects the amount of depression of the brake pedal or the brake fluid pressure. As a result, the braking force can be detected with high accuracy.

  Furthermore, as described in claim 5, it is preferable to cut off the power supply to the starter when the always-on failure of the starter is detected. As a result, it is possible to prevent a decrease in braking force due to the always-on failure of the starter and to protect the starter and the battery.

  The invention according to claims 1 to 5 described above can be applied to any vehicle regardless of the presence or absence of an idle stop system. However, when the present invention is applied to a vehicle equipped with an idle stop system, as in claim 6 Furthermore, it is preferable to prohibit the automatic stop (idle stop) of the idle operation by the automatic stop start control means when the always-on failure of the starter is detected. This is because if the starter's always-on failure occurs and the idle operation is automatically stopped, the starter's always-on failure may cause the engine to continue running or fail to restart normally. Because there is.

  Hereinafter, an embodiment in which the best mode for carrying out the present invention is applied to a vehicle equipped with an idle stop system will be described.

  First, a schematic configuration of the entire system will be described with reference to FIG. The brake pedal depression amount sensor 11 outputs a signal corresponding to the depression amount of the brake pedal, and functions as a brake force detection means. The vehicle speed sensor 12 outputs a signal corresponding to the vehicle speed and functions as a vehicle speed detection means. The inclination angle sensor 13 outputs a signal corresponding to the inclination angle of the traveling road or the inclination angle of the vehicle, and it is determined based on the output signal of the inclination angle sensor 13 whether or not the traveling road is a downhill ( This function corresponds to downhill judging means). The crank angle sensor 14 outputs a pulse signal every time the crankshaft of the engine rotates a predetermined crank angle, and the engine rotation speed is detected based on the interval (pulse frequency) of the pulse signal (this function is the engine rotation speed). Corresponds to detection means).

  Output signals of these various sensors 11 to 14 are taken into the control device 15. The control device 15 is mainly composed of a microcomputer, and outputs a control signal to the ignition device 16 and the fuel injection valve 17 according to the engine operating state to control the ignition timing and the fuel injection amount. Further, the control device 15 energizes the starter 18 to crank and start the engine when the driver operates the ignition key from the ON position to the START position.

  Further, the control device 15 also functions as an automatic stop / start control means, and a predetermined automatic stop condition (for example, throttle fully closed, accelerator fully closed or stopped, the engine rotation speed is equal to or less than a predetermined rotation number) during engine operation. When established, the fuel injection and ignition are stopped, and the idle operation is automatically stopped. During this automatic stop period, when the driver performs an operation for starting the vehicle (for example, depression of an accelerator pedal), an automatic start condition is established, and the starter 18 is energized to automatically start the engine.

  Further, the control device 15 executes the failure diagnosis routine of FIG. 2 at a predetermined period during engine operation, so that the vehicle speed or the engine rotation is achieved even though a braking force of a predetermined value or more is working on a road that is not downhill. Failure diagnosis means for diagnosing that a failure in which the starter 18 is always energized (hereinafter referred to as “always-on failure”) occurs when it is determined that the state in which the speed does not decrease according to the braking force continues for a predetermined time or longer. Function as. Hereinafter, processing contents of the failure diagnosis routine of FIG. 2 will be described.

  When the failure diagnosis routine of FIG. 2 is started, first, at step 101, whether or not the brake pedal depression amount detected by the brake pedal depression amount sensor 11 is greater than or equal to a predetermined value. Judge by whether or not. At this time, instead of the brake pedal depression amount, the brake fluid pressure (master back oil pressure) is detected by a pressure sensor, and the brake force is greater than or equal to a predetermined value depending on whether or not the brake fluid pressure is greater than or equal to a predetermined value. It may be determined whether or not.

  If it is determined in step 101 that the braking force is less than the predetermined value, the process proceeds to step 108, where the determination of “starter normal” is maintained and this routine is terminated. On the other hand, if it is determined in step 101 that the braking force is greater than or equal to a predetermined value, the process proceeds to step 102 where the vehicle speed detected by the vehicle speed sensor 12 is greater than or equal to the predetermined value or the engine speed is greater than or equal to the predetermined value. If it is determined as “No”, it is determined that the vehicle speed or the engine rotational speed has decreased according to the braking force, and the process proceeds to step 108 to determine “starter normal”. Keep this routine to finish.

  On the other hand, if “Yes” is determined in step 102, the vehicle speed or the engine rotation speed has not decreased in accordance with the braking force, so the cause is due to downhill or due to the always-on failure of the starter 18. To determine whether the traveling road is a downhill or not based on the output signal of the tilt angle sensor 13. As a result, if it is determined that the vehicle is downhill, it is determined that the reason why the vehicle speed or the engine speed does not decrease according to the braking force is due to the downhill, and the process proceeds to step 108 to maintain the determination of “starter normal”. To end this routine.

  If it is determined in step 103 that the travel path is not downhill, there is a possibility that the starter 18 is always on, so the process proceeds to step 104 where there is a possibility that the starter 18 is always on. It is determined whether or not (a state where the vehicle speed or the engine rotational speed is equal to or higher than a predetermined value despite a braking force of a predetermined value or more being applied on a traveling road that is not a downhill) continues for a predetermined time or more. The determination of “starter normal” is maintained until it continues for a predetermined time or longer (step 108).

Then, when the state where the starter 18 is likely to be always ON has continued for a predetermined time or longer, the process proceeds to step 105, the determination of “starter always ON failure” is confirmed, and the failure information is backed up to the control device 15. The information is stored in a rewritable non-volatile memory such as a RAM, and a warning lamp is lit or a warning is displayed on the display unit of the driver's instrument panel. Then, in the next step 106, the energization to the starter 18 is interrupted, and then the process proceeds to step 107, where idling stop (automatic stop of idling operation) is prohibited and this routine is terminated.
In step 102, the determination may be made by only one of the vehicle speed and the engine rotation speed (the determination of either the vehicle speed or the engine rotation speed may be omitted).

  According to the present embodiment described above, there is a possibility that the starter 18 is always ON (the vehicle speed or the engine rotational speed is predetermined even though a braking force of a predetermined value or more is applied on a road that is not downhill). Whether or not the starter 18 is always ON is determined based on whether or not the state in which the value is greater than or equal to a predetermined value) continues for a predetermined time or longer. Even if it is not provided, the always-on failure of the starter 18 can be diagnosed with high accuracy, and erroneous diagnosis of the always-on failure can be prevented. In addition, the sensors for detecting the braking force, vehicle speed, and engine rotation speed used for this failure diagnosis can share various sensors mounted on the vehicle for engine control and idle stop control. On the other hand, it is possible to mount the failure diagnosis function of the present embodiment only by changing the software without changing the hardware, and the demand for cost reduction can be satisfied.

  In addition, in the present embodiment, when the always-on failure of the starter 18 is detected, the idle stop is prohibited, so that the engine can continue to rotate due to the always-on failure of the starter 18 during the idle stop or can be restarted normally. It is possible to prevent problems that do not occur.

  In the system configuration of FIG. 1, one starter 18 is used as both a starter for manual start by key operation and a starter for idle stop. However, a starter for manual start and a starter for idle stop are used. You may make it provide separately. In this case, in order to determine which of the starter for manual start and the starter for idle stop is always on when a constant starter failure of the starter is detected in the same manner as in the above embodiment, Either one of the starters may be cut off and the same failure diagnosis may be performed again. As a result, only when an always-on failure of the starter for idling stop is found, idling stop is prohibited. You may do it.

  The present invention can be applied to a vehicle not equipped with an idle stop system. In this case, step 107 of the failure diagnosis routine of FIG. 2 may be omitted.

It is a block diagram which shows schematic structure of the whole system in one Example of this invention. It is a flowchart which shows the flow of a process of a failure diagnosis routine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Brake pedal depression amount sensor (brake force detection means), 12 ... Vehicle speed sensor (vehicle speed detection means), 13 ... Inclination angle sensor (downhill judgment means), 14 ... Crank angle sensor (engine speed detection means), 15 ... Control device (failure diagnosis means, automatic stop / start control means), 18 ... starter

Claims (6)

In a starter failure detection device that detects a failure of a starter that starts an engine,
Braking force detection means for detecting the braking force;
Vehicle speed detection means for detecting the vehicle speed;
Engine speed detecting means for detecting the engine speed;
Based on the detection results of the brake force detection means, the vehicle speed detection means, and the engine rotation speed detection means, the vehicle speed or the engine rotation speed decreases according to the brake force even though a brake force of a predetermined value or more is applied. And a failure diagnosis means for diagnosing that a failure in which the starter is always energized (hereinafter referred to as “always-on failure”) occurs when it is determined that the state of not being continued for a predetermined time or longer. Starter failure detection device. Downhill determination means for determining whether or not the traveling path is a downhill;
And a failure diagnosis prohibiting unit that prohibits failure diagnosis by the failure diagnosis unit when it is determined that the traveling road is a downhill based on a determination result of the downhill determination unit. The starter failure detection apparatus according to 1. An inclination angle sensor for detecting the inclination angle of the road or the inclination angle of the vehicle,
3. The starter failure detection device according to claim 2, wherein the traveling road gradient determining means determines whether or not the traveling road is a downhill based on an inclination angle detected by the inclination angle sensor.   The starter failure detection device according to any one of claims 1 to 3, wherein the brake force detection means detects a brake force based on an output of a sensor for detecting a brake pedal depression amount or a brake fluid pressure. .   The starter failure detection device according to any one of claims 1 to 4, wherein the failure diagnosis unit cuts off power to the starter when detecting an always-on failure of the starter. Idle operation is automatically stopped when a predetermined automatic stop condition is satisfied during engine idle operation, and the starter is energized to automatically start the engine when a predetermined automatic start condition is satisfied during the automatic stop period. Automatic stop start control means,
6. The starter according to claim 1, wherein the failure diagnosis unit prohibits the automatic stop of the idle operation by the automatic stop start control unit when the always-on failure of the starter is detected. Fault detection device.

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