JP2000145491A - Automatic starting system for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable identifying a faulty relay contact at an early stage by providing means that monitors a potential of a relay point of two relay contacts connected in series with each other during a period over which no starting signals are transmitted and means that records a history of abnormal values of the potential. SOLUTION: In a control circuit 1 that controls automatic starts and stops of an engine, a logic circuit 6 reads a potential at a relay point A of first and second relays 21, 22 connected in series with each other through a potential monitoring means 7 during a period through which a starting signal S is not transmitted to a relay circuit 4 as a result of a key switch 13 and a system switch 14 being turned ON. If the voltage at point A is high corresponding to a power source voltage with a starter switch 15 opened, it is considered that a contact of the first relay 21 is fused. If the voltage at point A is high corresponding to a power source voltage with the starter switch 15 closed, it is considered that a contact of the second relay 22 is fused. These faulty conditions are recorded by recording means 8 as a history of faulty values.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention is applied to automobiles.
The present invention is to automatically stop the engine when the logical condition of automatic stop is satisfied while the vehicle is stopped and to reduce the driving time due to the idling state of the engine when the ethical condition of automatic start is satisfied. The present invention relates to an improvement in a device for automatically starting an engine. In particular, it relates to an improvement for detecting and recording a malfunction of a relay circuit that short-circuits a start switch circuit.

[0002]

2. Description of the Related Art As a vehicle used for a route bus,
For vehicles that stop and start frequently, it is recommended that the engine be stopped while the vehicle is stopped, because if the engine is idling while the vehicle is stopped, the exhaust gas will cause air pollution and carbon dioxide emissions. I have. However, it is difficult for the driver to operate the engine key at each stop to stop the engine and start the engine by operating the engine key when starting. A device that automatically stops the engine when the condition is satisfied without operating the driver and automatically starts the engine when a certain logical condition of automatic start is satisfied has been used ( See Japanese Patent Application Laid-Open No. 9-158753).

This device utilizes the control of a program control circuit. For example, the logical conditions for automatic stop are that the vehicle speed is zero, the engine speed is the idling speed, and the transmission gear is in the neutral position. The condition is that the state in which the clutch is engaged (disengagement of the clutch pedal) continues for a fixed time (several seconds). In such a case, the program control circuit automatically shuts down the engine by shutting off the fuel flow path, shutting off the air intake path, or shutting off the ignition current without any operation by the driver. Control to make it.

Further, the program control circuit assumes that when the engine is automatically stopped, the shift gear is in the neutral position, and the clutch pedal is depressed, the logical condition of automatic start is satisfied. Even if the driver does not perform a start operation by a key switch, control is performed such that the start motor is automatically started to start the engine.

In this device, a relay circuit is used to automatically start an engine. That is, when the engine is started by a driving operation, the starter switch is closed by a manual operation using a key switch operated by the driver to create a current path for the starting motor. -The switch circuit is configured to be short-circuited by using a relay circuit that is opened and closed according to a start signal of the program control circuit.

[0006] A circuit for preventing malfunction by connecting two relay contacts in series has been adopted for this relay circuit. In other words, it is sufficient to short-circuit the starter switch circuit with one relay contact for the automatic start operation. However, in the unlikely event that a welding failure occurs at the relay contact, the drive current of the relay winding disappears. If the relay contacts are still not opened, the starter motor will continue to rotate in the same state as the starter switch is closed and not returned. This is a failure that makes it impossible to continue operation. Therefore, two relay contacts are used, and the two contacts are connected in series so that even if one of the relay contacts is welded, the vehicle cannot be driven immediately without causing a failure.

As the two relay contacts, two contacts driven by the same winding can be used, or two individual relays each having a separate winding can be used. Whether or not one of the two relay contacts connected in series is in a welded state is operated so as to be inspected at the time of periodic maintenance of the vehicle.

[0008]

However, the operation of checking whether or not one of the two relay contacts connected in series as described above is in a welded state is performed by an operator by visual inspection or continuity test. This is a work that requires man-hours. In addition, since it is a failure that rarely occurs, there is a possibility that it may be overlooked, and it is feared that it is not always reliable. In the inspection by visual inspection and continuity test, the initial state of failure where contact was found to be permanently welded, but was found to occur once but recovered due to vibration etc. Then, this cannot be reliably detected by visual inspection or continuity test.

If the operation is continued while one of the two relay contacts connected in series is in a welded state due to an inspection error or the like, when the other relay contact is welded, the operation becomes impossible immediately. Therefore, there is no point in increasing the reliability by connecting the relay contacts in series.

The present invention has been made in such a background, and one of two serially connected relay contacts has been found to be in a welded state by visual inspection of an operator or a continuity test. It is an object of the present invention to provide a device capable of detecting a target without detecting it. An object of the present invention is to reduce the number of work steps for inspection. An object of the present invention is to provide a device that can improve reliability by connecting relay contacts in series without the possibility of oversight by inspection. SUMMARY OF THE INVENTION It is an object of the present invention to provide a device that can detect a defective relay contact in an initial state.

[0011]

According to the present invention, an automatic start signal is not sent to determine whether or not two relay contacts provided in a relay circuit for short-circuiting a starter switch circuit are operating normally. Sometimes, the potential of the relay point of the two relay contacts is observed.

That is, the present invention provides a logic circuit (6) for sending out a start signal when a logical condition for automatic start is satisfied.
And a relay circuit (4) for supplying a power supply current to a start switch circuit (3) in response to the start signal. The relay circuit is inserted in a path for supplying the power supply current and interlocks in response to the start signal. In an automatic starter for an engine including two series-connected relay contacts that are closed in a closed state, the potential of a relay point (A) related to the series connection of the two relay contacts during a period in which the start signal is not transmitted. And means (8) for recording an abnormal value history of the potential.

It is preferable that a means is provided for inhibiting transmission of the start signal when the potential of the relay point (A) is equal to the power supply potential or the power supply side potential of the start switch circuit (3).

The potential at the relay point (point A in FIG. 1) for connecting two relay contacts in series is determined when the contacts of the two relays (21 and 22) are normal and there is no automatic start signal. That is, these two relay contacts are open (off)
When in the state, it should be at a floating potential that is not connected to any circuit. If the contact of one relay (the relay on the left side in FIG. 1) is welded and the contact is not released, the power supply potential (2
4V) will appear. If the contact of the other relay (the relay on the right side in FIG. 1) is welded and the contact is not opened, the potential of the power supply side of the winding of the start switch circuit (3) appears in the absence of a start signal. become. This means that when the starter switch (15) is not operated, the ground potential appears via the winding resistance of the start switch circuit (3).

Therefore, when the potential of the relay point is detected by the voltage detection circuit at a timing when the automatic start signal is not transmitted, whether or not the two relay contacts are welded is determined.
Further, when welding is performed, it is possible to detect which of the two pieces has been welded. Note that the reference numerals in the parentheses are reference numerals in the drawings for easy understanding of the description, and do not limit the scope of the right to the circuits in the attached drawings.

In the present invention, when it is detected that a failure has occurred in one of the two relay contacts, this abnormal value history is only recorded in the memory of the diagnostic circuit. Although a configuration may be adopted in which an alarm is generated when the occurrence of a failure is detected, the necessity is generally small due to the driving situation of the vehicle. The fact that one of the relay contacts has failed is not an urgent failure, but it is sufficient to be recognized at the time of maintenance and inspection. Therefore, by automatically recording this history in the memory of the diagnostic circuit and displaying an abnormality on a diagnostic monitor connected from the outside at the time of maintenance and inspection, it is possible to take appropriate measures.

Defective relay contacts are often not reproducible, and the contacts once in a welded state may be opened due to vibration or the like. If this fault is recorded in the memory of the diagnostic circuit, once a fault occurs, it will remain in the record even if it has recovered naturally, so that it can be examined further during maintenance and inspection .

Further, when a failure occurs in any one of the two relay contacts, the automatic start control (and the automatic stop control) of the engine may be stopped. That is, even if the automatic start control of the engine is stopped and cannot be used, there is no problem in a normal driving operation. The driver can start the engine by operating a normal starter switch and continue driving. And since the driver recognizes that the automatic start control of the engine has stopped,
Even if there is time before the maintenance and inspection cycle, the driver reports that there is a defect, which is checked, and the defect of the relay contact can be found earlier.

As described above, during the period when the start signal is not transmitted from the logic circuit, the potential of the relay point of the serial connection of the two relay contacts provided in the relay circuit is monitored, and the abnormal value history of the potential is monitored. The operator shall visually check or conduct a continuity test to determine whether the two relay contacts connected in series are in a welded state and, if so, which one has been welded. Without any detection.

As a result, the number of man-hours for inspecting the relay circuit can be eliminated, the oversight due to the inspection can be eliminated, and the defect of the relay contact can be found in an initial state to improve the reliability.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

[0022]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a main part of the apparatus according to the embodiment of the present invention.

The apparatus according to the embodiment of the present invention takes control information and controls the automatic stop and automatic start of the engine.
A starter motor 2 that rotates and starts an engine by supplying power, a start switch circuit 3 that opens and closes power to the starter motor 2, and a start switch circuit 3 based on a start signal from the control circuit 1. A closing relay circuit 4 and an engine stop means 5 for stopping the engine in response to a stop signal from the control circuit 1 are provided.

The relay circuit 4 has its contacts connected in series and the first relay 21 and the second relay 2 which open and close the relay contacts in conjunction with a start signal from the control circuit 1.
2 whose input is connected to the power supply and whose output is connected to the power supply of the start switch circuit 3.

The control circuit 1 has a logic circuit 6 for sending a start signal S when a logical condition for automatic start is satisfied, and a first circuit of the relay circuit 4 during a period when the start signal is not sent from the logic circuit 6. Potential monitoring means 7 for monitoring the potential of a relay point (that is, a contact to be a floating potential, point A in FIG. 1) related to the series connection of the relay contacts of the relay 21 and the second relay 22, and an abnormal value of the potential Recording means 8 for recording the history, first control means 11 for controlling the first relay 21 in accordance with a start signal S from the logic circuit 6, and second relay 22 in accordance with the start signal S from the logic circuit 6. , And failure detection means 9 for comparing the indicated value from the logic circuit 6 with the output from the first relay 21 and the second relay 22 to detect a failure. The recording means 8 is configured so that a diagnostic monitor 10 can be connected from the outside. The potential monitoring means 7 compares the potential of the relay point A with a preset reference potential.

The logic circuit 6 further includes means for inhibiting transmission of the start signal (S) when the potential of the relay point (point A) of the relay circuit 4 is equal to the power supply potential or the power supply side potential of the start switch circuit 3. And means for sending an engine stop signal when the logical condition of automatic engine stop is satisfied.

The control circuit 1 is started by turning on the key switch 13 and the system switch 14, and the starter switch
The motor 2 can be manually operated by closing the start switch circuit 3 by operating the starter switch 15.

The control circuit 1 includes, as control information, a clutch sensor 1 for detecting the engaged and disengaged states of the clutch.
6. Outputs of a neutral position sensor 17 for detecting a neutral position of the transmission, an engine rotation sensor 18 for detecting a rotation speed of the engine, a vehicle speed sensor 19 for detecting a vehicle speed, and an engine temperature sensor 20 for detecting a temperature of coolant of the engine. Is connected.

Next, a description will be given of an operation for detecting a malfunction of the relay circuit by the apparatus according to the embodiment of the present invention thus configured. When the key switch 13 and the system switch 14 are turned on and the automatic stop / start control of the engine is executed, the logic circuit 6 outputs the signal from the first control unit 11 and the second control unit 12. The start signal S is supplied to the first relay 21 and the second relay 22 of the relay circuit 4.
When the first relay 21 and the second relay 22 are not transmitted, the potential of the relay point A related to the series connection of the first relay 21 and the second relay 22 is taken from the potential monitoring means 7. Detect the operating state.

FIG. 2 is a flow chart showing the flow of the operation of detecting malfunction of the relay circuit by the apparatus according to the embodiment of the present invention.
In this embodiment, in the absence of the start signal S, the starter
If the switch 15 is open and the voltage at the point A is correspondingly high, the contact of the first relay 21 is in a welded state. If the starter switch 15 is closed and the voltage at the point A is correspondingly high, the second relay 21 is closed. It is configured to determine that the contacts of the two relays 22 are in a welded state. That is, a circuit having a configuration in which a preset reference potential V _S (for example, 5 V) lower than the power supply voltage (24 V) is set in the potential monitoring means 7 and the potential at the point A is compared with the reference potential V _S. Configuration.

The operation in the state where the start signal S is "present" in the flowchart shown in FIG. 2 is not directly related to the present invention.
By detecting the potential of the point A when the start signal S is "present", it is possible to detect the conduction failure of the first relay, and this is configured to be recorded for the convenience of maintenance. If any one of the first relay 21 and the second relay 22 has a conduction failure, the automatic start is not executed, and the driver declares this to the maintenance person. Which of the relays has failed can be identified by a maintenance person by looking at this record.

As described above, when the automatic start signal is not transmitted, the potential of the relay point A related to the series connection of the first relay 21 and the second relay 22 is detected.
The conduction failure of the first relay 21 of the relay circuit 4 can be detected, and which of the first relay 21 and the second relay 22 is welded can be detected.

Since the detected abnormal contents are recorded in the recording means 8 as an abnormal value history, when the diagnostic monitor 10 is connected from outside during maintenance and inspection, the abnormal contents are displayed on the diagnostic monitor 10. You.

Here, the automatic stop and automatic start operations of the engine according to the embodiment of the present invention will be described. First, the automatic engine stop operation of the embodiment of the present invention will be described. FIG. 3 is a flowchart showing the flow of the automatic engine stop operation by the apparatus according to the embodiment of the present invention.

When the engine is running, the logic circuit 6 takes the output of the clutch sensor 16 and determines whether the clutch is in the "disengaged" or "engaged" state. If the clutch is in the "engaged" state, the output of the neutral position sensor 17 is taken to determine whether the gear position of the transmission is at the neutral position. If the gear position of the transmission is in the neutral position, the output of the engine rotation sensor 18 is taken and it is determined whether or not the engine rotation speed is the idling speed.

If the engine speed is the idling speed, the output of the vehicle speed sensor 19 is taken in to determine whether or not the vehicle speed indicates zero. If the vehicle speed indicates zero, the output of the engine temperature sensor 20 is taken in, and it is determined whether or not the engine coolant temperature is normal. If the cooling water temperature of the engine is normal, all the conditions for automatically stopping the engine are satisfied, and the logic circuit 6 sends an engine stop signal to the engine stopping means 5. Engine stop means 5
Stops the engine by shutting off the fuel supply or the intake air supply according to this signal.

Next, the automatic engine start operation of the embodiment of the present invention will be described. FIG. 4 is a flowchart showing the flow of the automatic engine start operation by the apparatus according to the embodiment of the present invention.

The logic circuit 6 takes the output of the clutch sensor 16 when the vehicle is at a standstill, and determines whether the clutch is in a "disengaged" state or a "connected" state. If the clutch is in the "disengaged" state, the output of the engine rotation sensor 18 is taken and it is determined whether or not the engine is in the automatic stop state. If the engine is in the automatic stop state,
The output of the neutral position sensor 17 is taken, and it is determined whether or not the gear position of the transmission is at the neutral position.

If the gear position is in the neutral position, the output of the engine temperature sensor 20 is taken in to determine whether the engine coolant temperature is normal. If the cooling water temperature of the engine is normal, all the conditions for automatically starting the engine are satisfied, and the logic circuit 6 sets the first control means 1
A start signal is sent from the first and second control means 12 to the first relay 21 and the second relay 22 of the relay circuit 4, and the first relay 21 and the second relay 22 are turned on.

First relay 21 and second relay 22
Is turned on, the current from the power supply is supplied to the exciting coil of the start switch circuit 3 to turn on the contacts. As a result, the current from the power supply is supplied to the starter motor 2 and the engine is started.

[0041]

As described above, according to the present invention, one of the two serially connected relay contacts provided in the relay circuit for short-circuiting the start switch circuit at the time of automatic starting of the engine is in a welded state. Can be detected without the operator's visual observation or continuity test. Thereby, the number of work steps required for the inspection can be almost eliminated, and the possibility of oversight by the inspection can be eliminated. Further, since the failure of the relay contact can be found in an initial state, the reliability of the device can be improved.

Further, when any one of the two serially connected relay contacts is in a welded state, the automatic start operation of the engine is prohibited, so that the driver can recognize that maintenance is necessary. is there.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a main part of an apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of a relay circuit operation failure detecting operation by the apparatus according to the embodiment of the present invention;

FIG. 3 is a flowchart illustrating a flow of an automatic engine stop operation performed by the apparatus according to the embodiment of the present invention.

FIG. 4 is a flowchart showing a flow of an automatic engine start operation by the apparatus according to the embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control circuit 2 Starter motor 3 Start switch circuit 4 Relay circuit 5 Engine stop means 6 Logic circuit 7 Potential monitoring means 8 Recording means 9 Failure detection means 10 Diag monitor 11 First control means 12 Second control means 13 Key・ Switch 14 System switch 15 Starter switch 16 Clutch sensor 17 Neutral position sensor 18 Engine rotation sensor 19 Vehicle speed sensor 20 Engine temperature sensor 21 First relay 22 Second relay

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02N 15/10 F02N 15/10 Z F-term (Reference) 3G084 BA04 BA11 BA28 CA01 CA03 DA31 EB22 FA06 FA20 FA33 3G092 AC03 BA01 BB01 CA01 EA14 EC09 FA30 FB04 FB06 GA01 GA04 HE01Z HE08Z HF13Z HF15Z HF21Z 3G093 BA10 BA21 BA24 CA04 CA12 DA01 DA05 DA13 DB05 DB10 DB12 EA05 EA06

Claims (2)

[Claims] 1. A logic circuit for transmitting a start signal when a logical condition of automatic start is satisfied, and a relay circuit for supplying a power supply current to a start switch circuit in accordance with the start signal. An automatic starter for an engine including two serially connected relay contacts inserted into a passage for supplying electric current and closed in response to the start signal. An automatic engine starting device comprising: means for monitoring a potential at a relay point associated with a series connection of relay contacts; and means for recording an abnormal value history of the potential. 2. The automatic engine starting apparatus according to claim 1, further comprising means for inhibiting transmission of the start signal when the potential of the relay point is equal to a power supply potential or a power supply-side potential of the start switch circuit.