JP5764536B2 - Electronic control unit - Google Patents

Description

  The present invention mainly relates to an electronic control device (hereinafter referred to as C / U) for controlling an engine and an automatic transmission, and more particularly to a control device mounted on an automobile, a marine machine, an agricultural machine, and a construction machine.

  In recent years, with the intensification of competition for cost reduction, reduction and consolidation of automobile parts are frequently performed. Similarly, components for automatic transmissions have been reduced. As described in Patent Document 1, a configuration in which a harness on the downstream side of the solenoid is reduced is known.

JP-A-1-169159

  However, if the GND terminal of the C / U is disconnected and at least one drive circuit is stopped in a plurality of solenoid drive circuits, the circuit GND-diode-current detection resistor-solenoid-vehicle body GND-battery GND Thus, a pseudo GND path is formed, and the C / U operates even if the GND terminal of the C / U is disconnected. Since the pseudo GND path is via a diode, resistor, and solenoid, the impedance is large and the operation of the C / U becomes unstable. Therefore, the C / U operates when the GND terminal of the C / U is disconnected. Is not preferred.

  The present invention of claim 1 is an electronic control device for controlling a plurality of solenoids, one end of which is used for shift control of a vehicle transmission and having one end connected to a vehicle body ground, and a power source to which an external power source is connected. Terminals and ground terminals and a power generation circuit that starts operation when a voltage of an external power supply is applied to generate an internal power supply of the electronic control device, and a plurality of solenoids are provided respectively. A switching element provided between the connected power supply line and the other end of the solenoid, and provided for each of the plurality of solenoids, between the ground line connected to the ground terminal and the other end of the solenoid. The switch is operated by a semiconductor element connected to recirculate the current flowing through the solenoid and an internal power source generated by a power source generation circuit. The first control unit that controls each of the energizing elements to control the current flowing through the plurality of solenoids and the internal power source generated by the power generation circuit, and is controlled by the first control unit when the electronic control unit is activated And a second control unit that simultaneously turns on all of the switching elements provided in each of the plurality of solenoids, and controls the second control unit when the ground terminal is in an unconnected state. In this case, the operation of the power generation circuit is stopped.

  According to the present invention, it is possible to prevent the normal control of the solenoid from being performed when the GND terminal is not connected, and to provide a highly reliable electronic control device at a low cost.

It is a figure explaining the electronic controller by the 1st Embodiment of this invention. It is a figure explaining the starting sequence of C / U2 in 1st Embodiment. It is a figure explaining the starting sequence of C / U2 in 2nd Embodiment. It is a figure which shows the other example of C / U2. It is a figure which shows the structure of C / U for conventional automatic transmissions.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
-First embodiment-
FIG. 1 is a diagram for explaining a first embodiment of an electronic control unit (C / U) according to the present invention. The C / U 2 includes a power generation circuit 3, FETs 7 and 7a, a microcomputer 4, current detection resistors 8 and 8a, operational amplifiers 9 and 9a, and diodes 10 and 10a. The power supply generation circuit 3 generates a power supply in the C / U 2 using the power supplied from the battery 1. The FET 7, the current detection resistor 8, the operational amplifier 9 and the diode 10 constitute a solenoid drive circuit for driving the solenoid 11, and the FET 7a, the current detection resistor 8a, the operational amplifier 9a and the diode 10a constitute a solenoid drive circuit for driving the solenoid 11a. doing.

  The number of mounted solenoid drive circuits varies depending on the transmission system, but there are always a plurality of solenoid drive circuits. Although two solenoid drive circuits are provided in FIG. 1, the present invention can be similarly applied to a case where three or more systems are provided.

  The C / U 2 operates with the battery 1 as a power source, and mainly controls the current flowing through the solenoids 11 and 11a that are responsible for transmission shift control. In the solenoid drive circuit of the solenoid 11, the FET 7 functions as a switch for turning on and off the current flowing through the solenoid. The source of the FET 7 is connected to a power supply line 98 to which a battery voltage is applied, and the drain of the FET 7 is connected to one end of a solenoid 11 that is a load via a current detection resistor 8. The other end of the solenoid 11 is connected to the vehicle body ground.

  The diode 10 circulates the current flowing through the solenoid when the FET 7 is switched off. The anode of the diode 10 is connected to the ground line 97, and the cathode is connected to one end of the solenoid 11 via the current detection resistor 8. The current flowing through the solenoid 11 is detected as a voltage signal by the current detection resistor 8. The voltage signal obtained by the current detection resistor 8 is amplified by the operational amplifier 9 and input to the microcomputer 4.

  The current flowing through the solenoid 11 is controlled by switching the FET 7 based on the calculation result of the control calculation unit 5 provided in the microcomputer 4. The control calculation unit 5 calculates the target current of the solenoid 11 and performs feedback control based on the target current and the detected current so that the current flowing through the solenoid 11 becomes the target current. By changing the duty of the PWM control signal for controlling the FET 7, the current flowing through the solenoid 11 can be changed. The solenoid drive circuit related to the solenoid 11a also has the same configuration and function as the solenoid drive circuit of the solenoid 11.

  In the configuration shown in FIG. 1, one end of the solenoid 11 connected to the FET 7 via the current detection resistor 8 is connected to the vehicle body ground. Conventionally, as a typical automatic transmission C / U configuration, a configuration as shown in FIG. 5 is known. In the configuration shown in FIG. 5, a harness for driving the solenoid 11 is output from the C / U 2 and input to the C / U 2 via the solenoid 11. On the other hand, in the configuration of the present embodiment illustrated in FIG. 1, the harness on the downstream side of the solenoid is reduced by arranging the current detection resistor 8 from the downstream side to the upstream side of the solenoid 11.

  As described above, the configuration shown in FIG. 1 has the advantage that the harness can be reduced and the cost can be reduced, but has the disadvantages described above. That is, in a state where the GND connection line 22 of the GND terminal 20 of the C / U 2 is disconnected or disconnected and at least one of the plurality of solenoid drive circuits is stopped, the GND terminal 20 → A pseudo GND path 99 is formed as follows: diode 10 → current detection resistor 8 → solenoid 11 → vehicle body GND → battery GND. Therefore, even if the GND terminal 20 of the C / U 2 is in a disconnected state, the C / U 2 can operate with the vehicle body GND as a reference.

  As described above, when the GND terminal 20 is in a disconnected state, it is desirable that the C / U 2 does not operate and the function of the transmission is stopped. Therefore, in the present embodiment, by adopting the control described below, the operation when GND is not connected is prevented, and the reliability of C / U 2 is improved.

  FIG. 2 is a diagram for explaining an activation sequence of C / U 2 in the present embodiment. In FIG. 2, the part enclosed by the broken line is the activation sequence in the present embodiment. When the C / U 2 is activated, the process of the part enclosed by the broken line is first performed before starting the normal control from the past. Executed. In step S12, C / U2 is activated by a C / U activation signal from a host controller (not shown). When C / U2 is activated, in step S15, the microcomputer 4 operates all the solenoids 11 and 11a simultaneously. That is, the FETs 7 and 7a are turned on for a predetermined time (for example, 1 second).

  Here, when the GND connection line 22 connected to the GND terminal 20 is disconnected or disconnected, the potentials of the pseudo GND paths 99 and 99a become substantially the same as the power supply line 98 from the potential close to GND, The pseudo GND paths 99 and 99a are blocked. As a result, the power supply voltage of C / U2 (potential difference between the power supply terminal 21 and the GND terminal 20) becomes almost zero, the power supply generation circuit 3 is turned off, and the operation of C / U2 is stopped. The predetermined time described above is set longer than the time required until the power generation circuit 3 is turned off in the disconnected state. On the other hand, when the GND connection line 22 is normally connected, since the potential of the GND terminal 20 is held at the ground potential, all the solenoids 11 and 11a are simultaneously operated for a predetermined time in step S15. In addition, the power generation circuit 3 is not turned off.

  Step S16 shows branching of the flow depending on whether or not the GND terminal 20 is connected. If the GND terminal 20 is in an open state, the C / U 2 is automatically stopped as described above. On the other hand, if the GND terminal 20 is in the connected state, when the operations of the solenoids 11 and 11a stop after a predetermined time, the normal control in step S21 is started.

  When the GND terminal 20 is in the non-connected state, when the operation of C / U2 is stopped in step S17, the FETs 7 and 7a are turned off, so that the pseudo GND paths 99 and 99a become potentials close to GND again. As a result, the power supply voltage of C / U2 becomes the output voltage of battery 1, and when the input of the start signal is maintained, power supply generation circuit 3 starts operating and C / U2 is started again (step) S12). Hereinafter, the activation sequence (S12 → S15 → S16 → S17 → S12) shown in FIG. 2 is repeated, and C / U2 is repeatedly activated and stopped. Therefore, the normal control for driving the solenoids 11 and 11a is not performed, and the transmission is not controlled. A host controller (not shown) recognizes that C / U2 is not normal by detecting that the normal operation of step S21 is not started by repeating the operations of steps S12 to S17, and executes processing corresponding thereto. can do.

  The switching element provided in the solenoid drive circuit is not limited to the FET, and various semiconductor switching elements can be used. Further, although the diodes 10 and 10a are used as elements for returning the current flowing through the solenoids 11 and 11a when the FETs 7 and 7a are off, for example, FETs 17 and 17a may be used as shown in FIG. Since the FETs 17 and 17a have body diodes, they can function in the same manner as the diodes 10 and 10a. In the case of this configuration, the FETs 7 and 7a are turned on and off to control the currents of the solenoids 11 and 11a. At this time, the FETs 17 and 17a are turned on when the FETs 7 and 7a are turned off to recirculate the current. That is, the FETs 7 and 7a and the FETs 17 and 17a are alternately controlled on and off. The control of the FETs 17 and 17a is performed by the control calculation unit 5 of the microcomputer 4.

  As described above, the C / U 2 of the present embodiment controls the solenoids 11 and 11a, which are used for shift control of the vehicle transmission and one end of which is connected to the vehicle body ground. The power generation circuit 3 that generates the internal power of C / U 2 starts operation when the voltage of the battery 1 is applied to the power terminal 21. The control arithmetic unit 5 controls on / off of the FETs 7 and 7a provided between the other end of the solenoids 11 and 11a (that is, the side connected to the C / U 2 in the solenoids 11 and 11a) and the power supply line 98. Thus, the current flowing through the solenoids 11 and 11a is controlled. The other ends of the solenoids 11 and 11a are connected to the ground line 97 via the diodes 10 and 10a. For example, when the GND connection line 22 is disconnected from the GND terminal 20, the normal operation of the solenoids 11 and 11a is started. Before the control, all the FETs 7 and 7a are simultaneously turned on, so that the potential of the ground line 97 becomes substantially equal to the potential of the power supply line 98, the operation of the power supply generation circuit 3 is stopped, and C / U2 is Stop.

  That is, by executing the start-up sequence as shown in FIG. 2, it is possible to make a configuration in which normal control of the solenoids 11 and 11a is not executed when the GND terminal 20 is in the disconnected state, and the reliability is increased while suppressing an increase in cost. A highly electronic control device (C / U2) can be obtained.

-Second Embodiment-
In the first embodiment described above, when the GND terminal 20 is in a non-connected state, control is performed such that the processes in steps S12 to S17 in FIG. 2 are repeated, and normal control is not performed in the non-connected state. did. In the second embodiment, if it is detected that the GND terminal 20 is in a non-connected state by storing an activation flag (to be described later) in the storage device 6 built in the microcomputer 4 of the C / U 2, / U2 is controlled to stop safely.

  FIG. 3 is a diagram for explaining an activation sequence in the second embodiment. The flowchart of FIG. 3 is obtained by adding steps S13, S14, S18, S19, and S20 to the flowchart of FIG. In step S12, C / U2 is activated by a C / U activation signal from a host controller (not shown).

  When the C / U 2 is activated, the microcomputer 4 reads the activation flag data stored in the storage device 6 of the microcomputer 4 and determines whether the read activation flag is “OK” or “NG”. If the activation flag is “OK”, the process proceeds to step S14, and if it is “NG”, the process proceeds to step S18. In the following description, it is assumed that the activation flag when the GND terminal 20 is in the connected state is “OK”, and the activation flag when the unconnected state is detected is “NG”. Normally, the storage device 6 is built in the microcomputer 4, but may be an EEPROM or ROM external to the microcomputer. The activation flag is set in advance so as to be “OK” by default.

  First, the case where it is determined in step S13 that the activation flag is “OK” will be described. If it is determined in step S13 that the activation flag is “OK”, the process proceeds to step S14, and “NG” data is written in the activation flag. Next, in step S15, the microcomputer 4 operates all the solenoids 11 and 11a simultaneously. That is, all FETs 7 and 7a are simultaneously turned on. As a result, as in the case of the first embodiment, when the GND terminal 20 is not connected (OPEN), the C / U 2 stops (step S17).

  On the other hand, if the GND terminal 20 is in the connected state, the process proceeds from step S16 to step S20, and “OK” data is written in the activation flag. Then, it progresses to step S21 and starts normal control.

  When C / U2 is stopped in step S17, the FETs 7 and 7a are turned off and the pseudo GND paths 99 and 99a are again at a potential close to GND, as in the first embodiment. When the input of the activation signal is maintained, the C / U 2 is activated again (step S12). Since “NG” data is written in the storage device 6 in step S14 described above, the activation flag is “NG” after the restart, and it is determined as “NG” in the subsequent step S13. As a result, the process proceeds from step S13 to step S18. After writing "OK" data in the activation flag in step S18, the process proceeds to step S19, and the C / U 2 executes a stop operation.

  As described above, in the second embodiment, the C / U 2 can be safely stopped without repeatedly starting and stopping as in the case of the first embodiment. It should be noted that by providing the processing of step S18 and step S20 for writing “OK” data to the activation flag, it is configured to automatically return when the unconnected state of the GND terminal 20 returns.

  For example, when it is forgotten to connect the GND connection line 22 when the battery 1 is removed at the factory, when the ignition switch is turned on, the C / U 2 is stopped by the process of step S19. After that, when the GND connection line 22 is reconnected and the ignition switch is turned on again, if the process of step S18 is not performed, the stopped state remains. By adding the process of step S18, the flow of the activation sequence when automatically returning is S19 → S12 → S13 → S14 → S15 → S16 → S20 → S21. On the other hand, if it is desired to maintain the C / U2 stop state even after the GND disconnection failure is recovered, step S18 may be omitted and the start flag may be fixed to the “NG” state.

  As described above, in the second embodiment, by executing the startup sequence of FIG. 3, as in the case of the first embodiment described above, when the GND terminal 20 is in the non-connected state, the solenoids 11 and 11a. Therefore, it is possible to obtain a highly reliable electronic control device (C / U2) while suppressing an increase in cost.

  Furthermore, in the second embodiment, as shown in the startup sequence of FIG. 3, when the operation of the power generation circuit 3 is stopped by simultaneously turning on all the FETs 7 and 7a, “NG” Is stored in the storage device 6 and the C / U 2 is stopped when the activation flag of the storage device 6 is “NG” at the time of activation. Therefore, when C / U2 is temporarily stopped (step S17) and then restarted, “NG” is stored in the storage device 6, so that C / U2 is stopped by performing a stop operation. To do. As a result, when the GND terminal 20 is in a non-connected state, the C / U 2 stops after restarting without repeating stop and start as in the first embodiment.

  In addition, when “NG” is stored in the storage device 6 at the time of startup as in step S18 of the startup sequence in FIG. 3, “NG” in the storage device 6 is set before the C / U 2 is stopped. Is deleted to return to the default state (a state in which “OK” is stored). As a result, when the unconnected state becomes the connected state, it is possible to shift to a normal control operation without stopping again when the C / U 2 is restarted.

  Each of the embodiments described above may be used alone or in combination. This is because the effects of the respective embodiments can be achieved independently or synergistically. In addition, the present invention is not limited to the above embodiment as long as the characteristics of the present invention are not impaired.

  1: battery, 2: C / U, 3: power generation circuit, 4: microcomputer, 5: control operation unit, 6: storage device, 7, 7a, 17, 17a: FET, 8, 8a: current detection resistor, 10 , 10a: diode, 11, 11a: solenoid, 12, 12a: solenoid drive circuit, 20: GND terminal, 21: power supply terminal, 97: ground line, 98: power supply line,

Claims (3)

An electronic control device for controlling a plurality of solenoids, each of which is used for shift control of a vehicle transmission and has one end connected to a vehicle body ground,
A power supply terminal to which an external power supply is connected and a ground terminal;
A power generation circuit that starts operation when a voltage of the external power source is applied and generates an internal power source of the electronic control unit;
A switching element provided for each of the plurality of solenoids, and provided between a power supply line connected to the power supply terminal and the other end of the solenoid;
A semiconductor element provided for each of the plurality of solenoids, connected between a ground line connected to the ground terminal and the other end of the solenoid, and for returning a current flowing through the solenoid; ,
A first control unit that operates with an internal power source generated by the power source generation circuit and controls each of the switching elements to control a current flowing through the plurality of solenoids;
All of the switching elements provided in each of the plurality of solenoids are operated at the same time before being controlled by the first control unit when the electronic control device is activated by operating with the internal power source generated by the power source generation circuit. A second control unit to turn on,
The electronic control device according to claim 1, wherein when the ground terminal is in a disconnected state, the operation of the power generation circuit is stopped when the second control unit is controlled. The electronic control device according to claim 1.
A storage unit that stores a stop flag when the operation of the power generation circuit is stopped by the control of the second control unit;
An electronic control device, wherein when the stop flag is stored in the storage unit at the time of startup, the electronic control device is stopped without executing the control by the second control unit. The electronic control device according to claim 2,
When the stop flag is stored in the storage unit at the time of startup, the stop flag in the storage unit is erased before the electronic control device is stopped.

Images