JP2007246049A - Controller for hybrid electric car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the controller of a hybrid electric car for starting an engine, even when the start of an engine by a motor is put in difficult situations. <P>SOLUTION: The driving force of a motor 6 can be transmitted to a driving wheel 16 of a vehicle, and the rotary shaft of the motor 6 can be connected to the output shaft of an engine 2; and when the output torque of the motor 6 calculated based on a power which can be output by a battery 18 is smaller than predetermined torque, corresponding to torque necessary for starting the engine 2; and when the temperature of at least one of the motor 6 and an invertor 20 is not within a predetermined temperature range, or when the operating status of a start switch 38 can not be detected, the engine 2 is started by the start motor 38, in place of the motor 6, when a start switch 42 is operated at a start position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for a hybrid electric vehicle, and more particularly to a control device for a hybrid electric vehicle in which a driving force of an electric motor can be transmitted to a driving wheel of a vehicle and a rotating shaft of an electric motor and an output shaft of an engine can be connected.

Conventionally, a so-called parallel type hybrid electric vehicle has been developed and put into practical use in which an engine and an electric motor are mounted on a vehicle and the driving force of the engine and the driving force of the electric motor can be transmitted to the driving wheels of the vehicle, respectively.
In such a hybrid electric vehicle, since the output shaft of the engine and the rotating shaft of the electric motor can be connected, the engine can be started using the driving force of the electric motor operated by the motor.

A hybrid electric vehicle in which the engine is started using the driving force of the electric motor as described above is proposed by, for example, Patent Document 1.
In the hybrid electric vehicle of Patent Document 1, when a large driving force is required due to sudden acceleration of the vehicle while the engine is stopped and the vehicle is driven only by the electric motor, the engine is automatically started by the electric motor. Drive power is also supplied from the engine. At this time, if the battery voltage is lower than the set value or if the engine cranking signal is not detected, the engine cannot be started by the electric motor. To start.

Patent Document 2 also proposes a hybrid electric vehicle in which the engine is started using the driving force of the electric motor.
Similarly to the hybrid electric vehicle of Patent Document 1, the hybrid electric vehicle of Patent Document 2 requires a large driving force due to sudden acceleration of the vehicle when the engine is stopped and the vehicle is driven only by the electric motor. The engine is automatically started by the electric motor and the driving force is supplied from the engine. At this time, if the required torque is larger than the determination value, the driving force of the electric motor is used in addition to driving the vehicle by starting the engine with the electric motor, and the driving torque may be insufficient. Instead of the electric motor, the engine is started by a starting motor.
JP 2000-64873 A JP 2004-339943 A

  The battery used in such a hybrid electric vehicle gradually deteriorates with the passage of time of use, and the power that can be output decreases as the internal resistance increases. Since the hybrid electric vehicle of Patent Document 1 or 2 does not support such a decrease in output power that accompanies battery deterioration, the engine can be started with power supplied from the battery when the battery deteriorates. There is a problem that torque cannot be generated from the electric motor and the engine cannot be started.

  When starting an engine with a motor in a hybrid electric vehicle, the DC power of the battery is converted into AC power by an inverter, and this AC power is supplied to the motor to operate the motor. However, when the temperature of the motor is low and the viscosity of the lubricating oil of the motor is high, such as in cold regions, the torque required to rotate the motor itself increases, so the torque necessary to start the engine is transmitted to the engine. The problem arises that the engine cannot be started and the engine cannot be started.

On the other hand, even when the temperature of the electric motor or the inverter is excessively increased, the characteristic cannot generate a torque that can be output at normal temperature, and the engine cannot be started.
When the engine is started by the electric motor, the operating state of the start switch is detected, and the engine is started by the electric motor when the start switch is operated to the start position, but the operating state of the start switch is correctly detected. If this is not possible, there arises a problem that the engine is not started by the electric motor even when the start switch is set to the start position.

  The present invention has been made in view of such problems, and an object of the present invention is to control a hybrid electric vehicle that can start the engine even in a situation where it is difficult to start the engine with an electric motor. Is to provide.

  In order to achieve the above object, a control apparatus for a hybrid electric vehicle according to the present invention is a hybrid in which a driving force of an electric motor can be transmitted to driving wheels of a vehicle, and a rotating shaft of the electric motor and an output shaft of an engine can be connected. In a control device for an electric vehicle, a battery that stores electric power supplied to the electric motor, a starter motor that is provided separately from the electric motor and that can transmit the driving force to the output shaft of the engine and start the engine, and When the outputable torque of the electric motor is obtained based on the electric power that can be output from the battery, and the outputable torque is smaller than a predetermined torque set in advance corresponding to the torque required to start the engine by the electric motor. When the engine is started by the starter motor and the outputable torque is equal to or greater than the predetermined torque, By an electric motor, characterized in that a control means for starting the engine (claim 1).

  According to the control apparatus for a hybrid electric vehicle configured as described above, the outputable torque of the electric motor obtained based on the electric power that can be output by the battery corresponds to the torque necessary for starting the engine by the electric motor. When the torque is smaller than the predetermined torque set in advance, the engine is started by the starter motor. On the other hand, when the outputable torque is equal to or higher than the predetermined torque, the engine is started by the electric motor.

  In order to achieve the above object, the hybrid electric vehicle control apparatus of the present invention can transmit the driving force of the electric motor to the driving wheels of the vehicle and can connect the rotating shaft of the electric motor and the output shaft of the engine. In the control apparatus for a hybrid electric vehicle, the inverter for controlling the electric power supplied to the electric motor, the temperature detecting means for detecting the temperature of at least one of the electric motor and the inverter, and the electric motor are provided separately, A starting motor capable of transmitting the driving force to the output shaft of the engine and starting the engine, and when the temperature detected by the temperature detecting means is within a predetermined temperature range, the motor is started by the electric motor, while the temperature When the temperature detected by the detection means is not within the predetermined temperature range, the engine is operated by the starter motor. Characterized by comprising a dynamic control means (claim 2).

According to the hybrid electric vehicle control apparatus configured as described above, when the temperature of at least one of the electric motor and the inverter is within a predetermined temperature range, the engine is started by the electric motor, while at least one of the electric motor and the inverter is When the temperature is not within the predetermined temperature range, the engine is started by the starting motor.
In order to achieve the above object, the hybrid electric vehicle control apparatus of the present invention can transmit the driving force of the electric motor to the driving wheels of the vehicle and can connect the rotating shaft of the electric motor and the output shaft of the engine. In a control apparatus for a hybrid electric vehicle, a starter motor provided separately from the electric motor, capable of transmitting a driving force to the output shaft of the engine and starting the engine, and at least a start position for starting the engine A start switch having a stop position for stopping the engine; and an operating state of the start switch is detected, and the engine is started by the motor when the start switch is operated to the start position, When an abnormality that cannot detect the operating state of the start switch occurs, the start switch is operated to the start position. Instead of the electric motor, characterized in that a control means for starting the engine by the starter motor when it is (claim 3).

According to the hybrid electric vehicle control apparatus configured as described above, the engine is started by the electric motor when the start switch is operated to the start position, and an abnormality in which the operation state of the start switch cannot be detected occurs. In this case, when the start switch is operated to the start position, the engine is started by the start motor instead of the electric motor.
More specifically, in the control apparatus for the hybrid electric vehicle, from a power source provided so as to be able to supply power to the starter motor via the start switch, and from the power source via the start switch by opening a contact point. A cut relay that cuts off the power supply to the starter motor, and the starter switch allows the power supply from the power source to the starter motor when operated to the start position, while not in the start position. The energization from the power source to the starting motor is cut off, and the control means detects an operating state of the starting switch, opens the cut relay contact when the starting switch is operated to the starting position, and When the engine is started by the electric motor and the operating state of the start switch cannot be detected, the electric motor Serial and wherein the closing contacts of the cut relay without starting the engine (claim 4).

According to the hybrid electric vehicle control apparatus configured as described above, when the start switch is operated to the start position, the power supply from the power source via the start switch is cut off by opening the contact of the cut relay. Thus, the starting motor does not operate, and the motor is operated, so that the engine is started by the driving force of the electric motor.
On the other hand, when the operating state of the start switch cannot be detected, if the start switch is operated to the start position, the engine is not started by the electric motor, and the power source is supplied via the start switch by closing the contact of the cut relay. The start motor is energized from the start, and the engine starts when the start motor operates.

  According to the control apparatus for a hybrid electric vehicle of the present invention, the outputtable torque of the electric motor obtained based on the electric power that can be output by the battery is set in advance corresponding to the torque required to start the engine by the electric motor. When the torque is smaller than the predetermined torque, the engine is started by the starter motor. Therefore, even if the battery deteriorates and the output power can be reduced, the engine can be started reliably by the starter motor.

  Further, according to the control apparatus for a hybrid electric vehicle of the present invention, when the temperature of at least one of the electric motor and the inverter is not within the predetermined temperature range, the engine is started by the starting motor. Even when the torque is excessively lowered or raised and the original torque cannot be generated from the electric motor, the engine can be reliably started by the starting motor.

Further, according to the control apparatus for a hybrid electric vehicle of the present invention, when an abnormality in which the operation state of the start switch cannot be detected occurs, the engine is started by the start motor instead of the electric motor. Even when the operating state cannot be detected, the engine can be reliably started.
Further, according to the control apparatus for a hybrid electric vehicle of claim 4, in addition to the above-described effect, when the operation state of the start switch can be detected, the contact of the cut relay is set when the start switch is at the start position. Opening the power supply to the starter motor from the power source via the start switch is cut off and the starter motor does not operate. Therefore, there is an effect that the electric motor and the starter motor do not start the engine at the same time.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a main part of a control device for a hybrid electric vehicle 1 according to an embodiment of the present invention. An input shaft of the clutch 4 is connected to a crankshaft which is an output shaft of a diesel engine (hereinafter referred to as an engine) 2, and the output shaft of the clutch 4 is connected to a rotating shaft of a permanent magnet type synchronous motor (hereinafter referred to as an electric motor) 6. Thus, an input shaft of an automatic transmission (hereinafter referred to as a transmission) 8 is connected. The output shaft of the transmission 8 is connected to the left and right drive wheels 16 via a propeller shaft 10, a differential device 12 and a drive shaft 14.

Therefore, when the clutch 4 is connected, the output shaft of the engine 2 and the rotating shaft of the electric motor 6 are coupled and can be mechanically connected to the drive wheels 16 via the transmission 8, and the clutch 4 is disconnected. In this case, the connection between the output shaft of the engine 2 and the rotating shaft of the electric motor 6 is released, and only the rotating shaft of the electric motor 6 can be mechanically connected to the drive wheels 16 via the transmission 8.
The electric motor 6 operates as a motor when the direct-current power stored in the battery 18 is converted into alternating-current power by an inverter (power control means) 20 and supplied, and the drive torque is shifted to an appropriate speed by the transmission 8. Then, it is transmitted to the drive wheel 16. Further, when the vehicle is decelerated, the electric motor 6 operates as a generator, and kinetic energy generated by the rotation of the drive wheels 16 is transmitted to the electric motor 6 through the transmission 8 and converted into AC power, thereby generating regenerative braking torque. Then, the AC power is converted into DC power by the inverter 20, and then charged in the battery 18. The kinetic energy generated by the rotation of the drive wheels 16 is recovered as electric energy.

  On the other hand, the drive torque of the engine 2 is transmitted to the transmission 8 via the rotating shaft of the electric motor 6 when the clutch 4 is connected, and is transmitted to the drive wheels 16 after being shifted to an appropriate speed. It has become. Therefore, when the electric motor 6 operates as a motor when the driving torque of the engine 2 is transmitted to the driving wheels 16, the driving torque of the engine 2 and the driving torque of the electric motor 6 are respectively driven via the transmission 8. It will be transmitted to the wheel 16. That is, a part of the drive torque to be transmitted to the drive wheels 16 for driving the vehicle is supplied from the engine 2 and the remaining part is supplied from the electric motor 6.

When the charging rate (hereinafter referred to as SOC) of the battery 18 decreases and the battery 18 needs to be charged, the electric motor 6 operates as a generator, and the electric motor 6 is turned on using a part of the driving force of the engine 2. Power generation is performed by driving, and the generated AC power is converted into DC power by the inverter 20 and then the battery 18 is charged.
The vehicle ECU 22 (control means) performs connection / disconnection control of the clutch 4 and gear stage switching control of the transmission 8 in accordance with the operation state of the vehicle and the engine 2 and information from the engine ECU 24, the inverter ECU 26, and the battery ECU 28. At the same time, integrated control for appropriately driving the engine 2 and the electric motor 6 is performed in accordance with these control states and various driving states such as start, acceleration, and deceleration of the vehicle.

  The engine ECU 24 performs control for starting and stopping the engine 2 based on information from the vehicle ECU 22, and also operates the engine 2 itself such as idle operation control of the engine 2 and regeneration control of an exhaust gas purification device (not shown). The engine 2 controls the fuel injection amount and the injection timing so that the engine 2 generates the torque required for the engine 2 set by the vehicle ECU 22.

On the other hand, the inverter ECU 26 monitors the state of the electric motor 6 and the inverter 20 and sends the information to the vehicle ECU 22, and controls the inverter 20 based on the torque that should be generated by the electric motor 6 set by the vehicle ECU 22. 6 is operated by a motor or a generator.
The battery ECU 28 detects the temperature of the battery 18, the voltage of the battery 18, the current flowing between the inverter 20 and the battery 18, etc., and obtains the SOC of the battery 18 from these detection results. It is sent to the vehicle ECU 22 together with the detection result.

Then, the vehicle ECU 22 instructs the engine ECU 24 and the inverter ECU 26 to appropriately control the engine 2 and the electric motor 6 while mutually exchanging information with the engine ECU 24, the inverter ECU 26, and the battery ECU 28. The transmission 8 is appropriately controlled.
When the vehicle ECU 22 performs such control, an accelerator opening sensor 32 that detects the depression amount of the accelerator pedal 30, a vehicle speed sensor 34 that detects the traveling speed of the vehicle, and a rotation speed sensor 36 that detects the rotation speed of the electric motor 6. Based on the detection result, the required torque required for vehicle travel is calculated. Based on the information from each ECU, this required torque is distributed to the engine 2 and the electric motor 6 according to the driving state of the vehicle and the driving state of the engine 2 and the electric motor 6 at that time, and the engine ECU 24 and the inverter ECU 26 are instructed. At the same time, the transmission 8 and the clutch 4 are controlled as necessary.

At this time, when the torque is distributed only to the electric motor 6 and is not distributed to the engine 2, the vehicle ECU 22 disconnects the clutch 4 and uses the output torque of the electric motor 6 as the required torque for the inverter ECU 26. To instruct.
The engine ECU 24 idles the engine 2, while the inverter ECU 26 controls the inverter 20 according to the torque instructed by the vehicle ECU 22, and the DC power of the battery 18 is converted into AC power by the inverter 20 and supplied to the electric motor 6. The The electric motor 6 is operated by the AC power supplied thereto to output a required torque, and the output torque of the electric motor 6 is transmitted to the drive wheels 16 via the transmission 8.

When distributing torque to both the engine 2 and the electric motor 6, the vehicle ECU 22 connects the clutch 4 to instruct the engine ECU 24 about the output torque distributed to the engine 2 and to the inverter ECU 26. The output torque distributed to the electric motor 6 is instructed.
The engine ECU 24 controls the engine 2 so that the engine 2 outputs the torque instructed by the vehicle ECU 22, and the inverter ECU 26 controls the inverter 20 in accordance with the torque instructed by the vehicle ECU 22, thereby generating the output torque of the engine 2. The sum of the torque of the electric motor 6 becomes the required torque and is transmitted to the drive wheels 16 via the transmission 8.

On the other hand, when the torque is distributed only to the engine 2 and is not distributed to the electric motor 6, the vehicle ECU 22 instructs the engine ECU 24 to set the output torque of the engine 2 as the required torque by connecting the clutch 4. At the same time, the inverter ECU 26 is instructed to make the output torque of the electric motor 6 zero.
The engine ECU 24 controls the engine 2 so that the engine 2 outputs the required torque instructed by the vehicle ECU 22, and the inverter ECU 26 controls the inverter 20 so that the electric motor 6 does not operate as either a motor or a generator. The required torque output from the engine 2 is transmitted to the drive wheels 16 via the transmission 8.

Incidentally, since the rotating shaft of the electric motor 6 can be connected to the output shaft of the engine 2 via the clutch 4, the engine 2 can be started by operating the electric motor 6 with a motor. However, in consideration of the case where the electric motor 6 cannot output the torque necessary for starting the engine 2 for some reason, the engine 2 is provided with a starting motor 38 separately from the electric motor 6.
The starter motor 38 is the same as an engine starter motor provided in a general vehicle using only the engine as a drive source, and a detailed description thereof is omitted, but a ring gear attached to the output shaft end of the engine 2 is omitted. A pinion gear (not shown) meshed with a ring gear (not shown) is provided, and the output shaft of the engine 2 is driven by the pinion gear meshed with the ring gear so that the engine 2 can be started.

The vehicle ECU 22 performs switching between the start of the engine 2 using the starter motor 38 and the start of the engine 2 by the electric motor 6 as appropriate, and at this time, the starter control unit 40 for controlling the starter motor 38 is provided. Have. A control circuit configuration of the starter motor 38 including the start control unit 40 is shown in FIG.
As shown in FIG. 2, when the first contact 42 a of the start switch 42 is closed, the starting motor 38 is supplied with electric power from the power supply battery (power source) 46 through the first contact 42 a and the contact 44 a of the cut relay 44. It has become so. The power battery 46 is not only used to supply power to the starter motor 38, but also includes various devices used for operation control of the engine 2, the clutch 4, and the transmission 8 including the vehicle ECU 22, the inverter ECU, and the battery ECU 28. Power is also supplied to sensors.

  The start switch 42 shuts off the power supply from the power source battery 46 to each ECU, device, and sensor and at the same time is an off position (stop position) for stopping the engine 2, an on position for supplying the power, In addition, it is possible to switch to three starting positions for starting the engine 2, and automatically return to the on position when the operator releases the hand after switching from the on position to the starting position. When the start switch 42 is operated to the start position, the first contact 42a is closed, and when it is in the off position and the on position, the first contact 42a is opened.

The contact 44a of the cut relay 44 is a normally closed contact and opens when the electromagnetic coil 44b is energized and excited.
The electromagnetic coil 44b of the cut relay 44 has one end connected to the positive electrode of the power supply battery 46 and the other end connected to the terminal t3 of the start control unit 40, and is excited by a control signal from the start control unit 40. It is like that.

  Accordingly, when the start switch 42 is operated to the start position while the contact 44a of the cut relay 44 is closed and the first contact 42a of the start switch 42 is closed, power is supplied from the power supply battery 46 to the start motor 38, and the start motor 38 operates, while the electromagnetic coil 44b of the cut relay 44 is excited and the contact 44a is opened, the power supply from the power battery 46 to the starter motor 38 is cut off even when the first contact 42a of the start switch 42 is closed. Thus, the starter motor 38 does not operate.

The start switch 42 has a second contact 42b that operates in the same manner as the first contact 42a. One end of the second contact 42b is connected to the positive electrode of the power battery 46, and the other end has two signal lines 48a and The start control unit 40 is connected to terminals t1 and t2 via 48b, and the start control unit 40 detects the operating state of the start switch 42.
Here, the operation state of the start switch 42 is detected via the two signal lines 48a and 48b. This is because the signal lines 48a and 48b are normally connected to the start control unit 40. This is to detect.

  That is, if either one of the signal lines 48a and 48b is disconnected, for example, if the signal line 48a is disconnected, the start switch 42 is operated to the start position and the second contact 42b is closed. The voltage of the power supply battery 46 (hereinafter referred to as power supply voltage) is applied to the terminal t2 of the start control unit 40 via the simple signal line 48b, but the power supply voltage is applied to the terminal t1 because the signal line 48a is disconnected. The voltage at the terminal t1 is 0V.

  In addition, when either one of the signal lines 48a and 48b is disconnected and the disconnected end on the start control unit 40 side is in contact with the portion to which the power supply voltage is applied, for example, the signal line 48a is in such a state. Assuming that the power supply voltage is not applied to the terminal t2 of the start control unit 40 to which the normal signal line 48b is connected when the second contact 42b is opened while the start switch 42 is not operated to the start position. The voltage at the terminal t2 is 0V, but the power supply voltage is applied to the signal line 48a.

As described above, when either of the two signal lines 48a and 48b is abnormal, the voltages at the terminals t1 and t2 are different. Therefore, the start control unit 40 monitors the voltages at the terminals t1 and t2. Whether the signal lines 48a and 48b are normal is monitored.
The start control unit 40 has a ground terminal G and a power supply terminal P to which the power battery 46 is connected, and is used for supplying power into the start control unit 40.

Using the control circuit of the starter motor 38 configured as described above, the start control unit 40 performs start control according to the flowchart shown in FIG. This start control is started when the start switch 42 is switched from the off position to the on position.
When the start control is started, it is first determined in step S1 whether or not the start switch 42 has been set to the start position. If the start switch 42 is not in the start position, the process of step S1 is repeated to enter a standby state. When the start switch 42 is operated to the start position, the process proceeds to step S2 to determine whether or not it is difficult to start the engine 2 by the electric motor 6.

In step S2, the first to fourth states are determined as states in which it is difficult to start the engine 2 by the electric motor 6.
The first state relates to the power that can be output from the battery 18. The battery 18 gradually deteriorates with repeated use, and the power that can be output gradually decreases. Therefore, the start control unit 40 obtains the internal resistance of the battery 18 from the detection result of the voltage and current of the battery 18 sent from the battery ECU 28 to the vehicle ECU 22, and the deterioration coefficient indicating the degree of deterioration of the battery 18 from the change of the internal resistance. Is calculated. Then, the power that can be output from the current battery 18 is obtained by multiplying the power that can be output when the battery 18 is new by this deterioration coefficient, and the torque that the motor 6 can output when this power is supplied to the motor 6. Is calculated.

The start control unit 40 stores in advance torque (predetermined torque) that is set slightly larger than the output torque of the electric motor 6 that is required when the engine 2 is started by the electric motor 6, and the electric motor 6 outputs the torque. When the possible torque is less than the starting torque, it is determined that it is difficult to start the engine 2 by the electric motor 6.
The second state relates to the temperature of the engine 2. When the temperature of the engine 2 is greatly decreased in a cold region or the like, the viscosity of the lubricating oil of the engine 2 increases, and the torque necessary for starting the engine 2 increases. For this reason, when the temperature of the engine 2 detected by the engine temperature sensor 50 that detects the temperature of the engine 2 becomes lower than a predetermined temperature, it is determined that it is difficult to start the engine 2 by the electric motor 6.

  The third state relates to the temperatures of the electric motor 6 and the inverter 20. When the temperature of the electric motor 6 is greatly lowered in a cold region or the like, the viscosity of the lubricating oil of the electric motor 6 is increased, so that the torque necessary for starting the engine 2 is increased. Moreover, when the temperature of the electric motor 6 or the inverter 20 rises greatly, it becomes impossible to generate normal output torque. For this reason, when the temperature of the electric motor 6 detected by the electric motor temperature sensor (temperature detection means) 52 that detects the temperature of the electric motor 6 falls outside the predetermined range, it is determined that it is difficult to start the engine 2 by the electric motor 6. To do.

  The electric motor 6 and the inverter 20 are provided with a common cooling water passage (not shown), and the electric motor temperature sensor 52 detects the cooling water temperature in the cooling water passage as the temperature of the electric motor 6. Therefore, the temperature detected by the motor temperature sensor 52 also represents the temperature of the inverter 20. However, when the temperatures of the electric motor 6 and the inverter 20 are not detected by a common temperature sensor as in the present embodiment, but are detected by separate temperature sensors, and one of the temperatures falls outside the predetermined temperature range, the electric motor Alternatively, it may be determined that it is difficult to start the engine 2 with 6.

  The fourth state relates to the signal lines 48 a and 48 b connected from the start switch 42 to the start control unit 40. If any one of the signal lines 48a and 48b for detecting the operation state of the start switch 42 is abnormal, it cannot be determined which signal line is normal, and therefore the operation state of the start switch 42 is correctly detected. I can't. For this reason, if the engine 2 is started by the electric motor 6, the engine 2 may be started simultaneously by the electric motor 6 and the start motor 38 and the start motor 38 may be damaged. And when the abnormality occurs in either of 48b, it is determined that it is difficult to start the engine 2 by the electric motor 6.

If it is determined in step S2 that none of these four states is applicable and it is not difficult to start the engine 2 by the electric motor 6, the process proceeds to step S3, and a power supply voltage signal is output from the terminal t3 of the start control unit 40. By doing so, the electromagnetic coil 44b of the cut relay 44 is excited and the contact 44a is opened.
Next, when the process proceeds to step S4, the power supply from the power battery 46 to the starter motor 38 via the first contact 42a of the start switch 42 is cut off by opening the contact 44a of the cut relay 44. Since 38 does not operate, the start control unit 40 permits the start of the engine 2 by the electric motor 6.

In response to this, the vehicle ECU 22 confirms that the transmission 8 is in the neutral position, the mechanical connection between the electric motor 6 and the drive wheel 16 is cut off, and the clutch 4 is connected, and then the inverter ECU 26 Instructing the output torque of the electric motor 6 necessary for starting the engine 2 and instructing the engine ECU 24 to operate the engine 2.
Based on an instruction from the vehicle ECU 22, the inverter ECU 26 operates the motor 6 to generate an output torque instructed by the vehicle ECU 22 to crank the engine 2, and the engine ECU 24 starts supplying fuel to the engine 2. By doing so, the engine 2 is started and the start control is ended.

  As described above, when the engine 2 is started by the electric motor 6, energization from the power supply battery 46 to the starter motor 38 via the first contact 42 a of the start switch 42 by opening the contact 44 a of the cut relay 44. Since the starting motor 38 does not operate, the electric motor 6 and the starting motor 38 start the engine 2 at the same time and the starting motor 38 is damaged.

On the other hand, if it is determined in step S2 that it is difficult to start the engine 2 by the electric motor 6 in any of the first to fourth states, the process proceeds to step S5, and the terminal t3 of the start control unit 40 is set. To 0V, the electromagnetic coil 44b of the cut relay 44 is de-energized and the start by the start motor 38 is permitted in step S6.
Since the contact 44a is closed when the electromagnetic coil 44b of the cut relay 44 is de-energized in this way, the power from the power supply battery 46 to the starter motor 38 is closed when the first contact 42a of the start switch 42 is closed. Is supplied, the pinion gear of the starter motor 38 meshes with the ring gear, and the driving force of the starter motor 38 is transmitted to the output shaft of the engine 2.

At this time, the vehicle ECU 22 receives a start permission from the start motor 38, disconnects the clutch 4 and disconnects the connection between the output shaft of the engine 2 and the rotating shaft of the electric motor 6, and instructs the engine ECU 24 to operate the engine 2. To do.
When the engine ECU 24 receives an instruction from the vehicle ECU 22 and starts supplying fuel to the engine 2, the engine 2 starts and the start control ends.

As described above, when starting the engine 2 with the start switch 42 as the start position, if it is detected that the engine 2 is difficult to start by the electric motor 6, the engine 2 is started by the starter motor 38. Therefore, the engine 2 can be reliably started.
In particular, when the torque that can be output from the electric motor 6 obtained based on the electric power that can be output by the battery 18 is smaller than the starting torque required to start the engine 2 by the electric motor 6, the engine 2 by the electric motor 6 is used. Therefore, even if the battery 18 deteriorates and the power that can be output decreases, the engine 2 can be reliably started by the starter motor 38.

In addition, when the temperature of the electric motor 6 and the inverter 20 is not within the predetermined temperature range, it is determined that it is difficult to start the engine 2 by the electric motor 6, so that the temperature of the electric motor 6 and the inverter 20 is excessively lowered or Even in the case where the engine cannot rise and generate the original torque, the engine can be reliably started by the starting motor 38.
When the temperatures of the electric motor 6 and the inverter 20 are separately detected, it is determined that it is difficult to start the engine 2 by the electric motor 6 when one of the temperatures is not within the predetermined temperature range. The same effect can be obtained.

  Further, when the operation state of the start switch 42 cannot be detected due to an abnormality in the signal line 48a or 48b, it is determined that it is difficult to start the engine 2 by the electric motor 6. Therefore, the operation state of the start switch 42 is determined. Even when the engine cannot be detected, the engine can be reliably started by the start motor 38 when the start switch 42 is operated to the start position.

Although the description of the control apparatus for a hybrid electric vehicle according to one embodiment of the present invention is finished above, the present invention is not limited to the above embodiment.
For example, in the above-described embodiment, the internal resistance of the battery 18 is obtained based on the voltage and current of the battery 18 and the degree of deterioration of the battery 18 is detected from the change in the internal resistance. However, the detection is not limited to this, and the detection may be performed based on the integrated current value after the start of use of the battery 18 or the like, and various known methods may be employed.

In the above embodiment, the electric motor 6 is arranged between the clutch 4 and the transmission 8. However, the arrangement of the electric motor 6 is not limited to this. For example, the electric motor 6 is arranged between the engine 2 and the clutch 4. It may be a hybrid electric vehicle in which the electric motor 6 is arranged.
In the above embodiment, the engine 2 is a diesel engine, but the engine type is not limited to this, and a gasoline engine or the like may be used.

  Moreover, in the said embodiment, although the electric motor 6 was made into the permanent magnet type synchronous motor, the form of an electric motor is not restricted to this.

1 is an overall configuration diagram of a control apparatus for a hybrid electric vehicle according to an embodiment of the present invention. It is a figure which shows the starting control part and its peripheral circuit in the control apparatus of the hybrid electric vehicle of FIG. It is a flowchart of the start control performed by a start control part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hybrid electric vehicle 2 Engine 6 Electric motor 16 Drive wheel 18 Battery 22 Vehicle ECU (control means)
38 Start Motor 40 Start Control Unit 42 Start Switch 44 Cut Relay 46 Power Supply Battery (Power Supply)
52 Electric motor temperature sensor (temperature detection means)

Claims (4)

In the control apparatus for a hybrid electric vehicle, the driving force of the electric motor can be transmitted to the driving wheels of the vehicle, and the rotation shaft of the electric motor and the output shaft of the engine can be connected.
A battery for storing electric power supplied to the electric motor;
A starter motor provided separately from the electric motor, capable of transmitting the driving force to the output shaft of the engine and starting the engine;
The outputable torque of the electric motor is obtained based on the electric power that can be output by the battery, and the outputable torque is smaller than a predetermined torque set in advance corresponding to the torque required to start the engine by the electric motor. And a control means for starting the engine by the starting motor and starting the engine by the electric motor when the outputable torque is equal to or greater than the predetermined torque. In the control apparatus for a hybrid electric vehicle, the driving force of the electric motor can be transmitted to the driving wheels of the vehicle, and the rotation shaft of the electric motor and the output shaft of the engine can be connected.
An inverter for controlling electric power supplied to the electric motor;
Temperature detecting means for detecting the temperature of at least one of the electric motor and the inverter;
A starter motor provided separately from the electric motor, capable of transmitting the driving force to the output shaft of the engine and starting the engine;
The engine is started by the electric motor when the temperature detected by the temperature detecting means is within a predetermined temperature range, and when the temperature detected by the temperature detecting means is not within the predetermined temperature range, the engine is started by the starting motor. And a control means for starting the engine. In the control apparatus for a hybrid electric vehicle, the driving force of the electric motor can be transmitted to the driving wheels of the vehicle, and the rotation shaft of the electric motor and the output shaft of the engine can be connected.
A starter motor provided separately from the electric motor, capable of transmitting the driving force to the output shaft of the engine and starting the engine;
A start switch having at least a start position for starting the engine and a stop position for stopping the engine;
When the operation state of the start switch is detected, and the engine is started by the electric motor when the start switch is operated to the start position, and an abnormality in which the operation state of the start switch cannot be detected occurs. And a control means for starting the engine by the start motor instead of the electric motor when the start switch is operated to the start position. A power source provided to supply power to the starter motor via the start switch;
A cut relay that cuts off the energization from the power source to the start motor via the start switch by opening a contact;
The start switch allows energization from the power source to the start motor when operated to a start position, while interrupting energization from the power source to the start motor when not in the start position,
The control means detects the operating state of the start switch, and when the start switch is operated to the start position, opens the contact of the cut relay and starts the engine by the electric motor, 4. The control device for a hybrid electric vehicle according to claim 3, wherein when the operating state cannot be detected, the contact of the cut relay is closed without starting the engine by the electric motor.

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