JP7593260B2 - Vehicle control device - Google Patents

Description

The present invention relates to a vehicle control device.

In a vehicle that operates an internal combustion engine intermittently, if power consumption increases, the opportunities for the internal combustion engine to be automatically stopped decrease, which may result in a deterioration in fuel efficiency. Therefore, for example, in the vehicle described in Patent Document 1, power consumption is reduced by stopping the flow of electricity to the solenoid valve installed in the cooling system of the internal combustion engine during automatic stopping of the internal combustion engine.

JP 2016-114025 A

In order to further improve fuel efficiency in internal combustion engines, there is a demand to reduce power consumption by suppressing unnecessary power consumption.

The vehicle control device that solves the above problem is a vehicle control device that automatically stops and automatically restarts an internal combustion engine equipped with a hydraulic control valve, and controls the state of electricity supply to the hydraulic control valve. When a request to execute the automatic stop is made and the engine speed of the internal combustion engine is equal to or less than 0, the control device executes an electricity supply stop process that stops electricity supply to the hydraulic control valve.

According to this configuration, when all of the above conditions are satisfied, the power supply to the hydraulic control valve is stopped, thereby making it possible to reduce power consumption during the automatic stop.
In addition, the control device may execute a wire break diagnosis process for checking whether or not there is a wire break in the hydraulic control valve while current is being applied to the hydraulic control valve, and a process for temporarily applying current to the hydraulic control valve while the current stop process is being executed.

With this configuration, even when the above-mentioned de-energization process is being performed, electricity is temporarily supplied to the hydraulic control valve, so the above-mentioned disconnection diagnosis process can be performed while the internal combustion engine is automatically stopped.

In addition, in the control device, the vehicle is a hybrid vehicle equipped with the internal combustion engine and an electric motor as a driving source for traveling, and during the automatic stop, a stop position control may be implemented in which the electric motor is driven to stop the piston of the internal combustion engine at a specified target position.

When the stop position control is performed, the crankshaft of the internal combustion engine may be rotated in reverse by the electric motor, causing the engine speed to become negative. In this regard, the conditions for performing the de-energization process include the engine speed being equal to or less than 0. Therefore, the de-energization process can be performed even when the crankshaft is rotating in reverse due to the implementation of the stop position control.

1 is a diagram illustrating a first embodiment of a vehicle control device and a configuration of a drive system of a vehicle to which the device is applied; 2 is a diagram showing a schematic configuration of an internal combustion engine mounted on the vehicle. FIG. 4 is a flowchart showing a processing procedure executed by the control device. 10 is a flowchart showing a process executed by a control device according to a second embodiment;

First Embodiment
A first embodiment of a vehicle control device will be described below with reference to FIGS. 1 to 3. FIG.
<Vehicle drive system configuration>
As shown in Fig. 1, the vehicle is a hybrid vehicle equipped with an internal combustion engine 10 and an electric motor 15 as driving sources for traveling. A transmission unit 11 is provided in a power transmission path from the internal combustion engine 10 to wheels 13 in this vehicle. The transmission unit 11 and the left and right wheels 13 are drivingly connected via a differential 12.

The transmission unit 11 is provided with a clutch 14 and an electric motor 15. In the transmission unit 11, the electric motor 15 is installed so as to be located on the power transmission path from the internal combustion engine 10 to the wheels 13. The clutch 14 is installed so as to be located in a portion of the power transmission path between the internal combustion engine 10 and the electric motor 15. The clutch 14 is engaged when hydraulic pressure is supplied, connecting the power transmission between the internal combustion engine 10 and the electric motor 15. The clutch 14 is released when the hydraulic pressure supply is stopped, cutting off the power transmission between the internal combustion engine 10 and the electric motor 15.

The electric motor 15 is connected to the on-board power supply 16 via the inverter 17. The electric motor 15 functions as a motor that generates driving force for the vehicle in response to power supplied from the on-board power supply 16, while also functioning as a generator that generates power to charge the on-board power supply 16 in response to power transmission from the internal combustion engine 10 and the wheels 13. The power exchanged between the electric motor 15 and the on-board power supply 16 is adjusted by the inverter 17.

The transmission unit 11 is provided with a torque converter 18, which is a fluid coupling with a torque amplifying function, and a stepped automatic transmission 19 that switches the gear ratio in multiple stages by changing the gear stage. In the transmission unit 11, the automatic transmission 19 is installed so as to be located in a portion of the power transmission path closer to the wheels 13 than the electric motor 15. The electric motor 15 and the automatic transmission 19 are connected via the torque converter 18. The torque converter 18 is provided with a lock-up clutch 20 that receives a supply of hydraulic pressure, engages, and directly connects the electric motor 15 and the automatic transmission 19.

The transmission unit 11 is further provided with an oil pump 21 and a hydraulic control unit 22. The hydraulic pressure generated by the oil pump 21 is supplied to the clutch 14, the torque converter 18, the automatic transmission 19, and the lock-up clutch 20 via the hydraulic control unit 22. The hydraulic control unit 22 is provided with hydraulic circuits for the clutch 14, the torque converter 18, the automatic transmission 19, and the lock-up clutch 20, as well as various hydraulic control valves for controlling the operating hydraulic pressures thereof.

In addition, the vehicle is provided with a control device 23. The control device 23 is configured as an electronic control unit equipped with a calculation processing circuit that performs various calculation processes related to the vehicle's driving control, and a storage device in which control programs and data are stored. The control device 23 controls the operation of the internal combustion engine 10. The control device 23 also controls the inverter 17 to adjust the amount of power exchanged between the electric motor 15 and the on-board power source 16, thereby controlling the torque of the electric motor 15. Furthermore, the control device 23 controls the drive of the clutch 14, the lock-up clutch 20, and the automatic transmission 19 through the control of the hydraulic control unit 22. The control device 23 receives detection signals from sensors that grasp the operating conditions of the internal combustion engine 10, the electric motor 15, etc.

<Configuration of the internal combustion engine>
2, the internal combustion engine 10 is provided with cylinders 30 that combust an air-fuel mixture. In the figure, only one of the multiple cylinders 30 that the internal combustion engine 10 has is shown.

A piston 31 is housed in each cylinder 30 so that it can reciprocate. The piston 31 of each cylinder 30 is connected to a crankshaft 33, which is the output shaft of the internal combustion engine 10, via a connecting rod 32.

The connecting rod 32 and the crankshaft 33 constitute a crank mechanism that converts the reciprocating motion of the piston 31 into the rotational motion of the crankshaft 33. The internal combustion engine 10 is provided with a crank angle sensor 34 that detects the rotation angle of the crankshaft 33. A variable displacement oil pump 60 that delivers oil to each part of the internal combustion engine 10 is also connected to the crankshaft 33.

The oil pump 60 is equipped with a first hydraulic control valve 61. The first hydraulic control valve 61 is a linear solenoid valve equipped with an electromagnet, and the discharge volume of the oil pump 60 is changed by changing the first excitation current I1, which is the excitation current supplied to this electromagnet. In addition, a first current detection circuit 62 that detects the first excitation current I1 flowing through the electromagnet is connected to the electromagnet of the first hydraulic control valve 61.

An intake passage 35, which is an intake passage for intake air, is connected to each cylinder 30 of the internal combustion engine 10 via an intake valve 36. The intake valve 36 is provided with an electrically operated variable valve mechanism 70 that changes the valve timing of the intake valve 36.

An exhaust passage 37, which is an exhaust passage, is connected to each cylinder 30 of the internal combustion engine 10 via an exhaust valve 38. The exhaust valve 38 is provided with a hydraulic variable valve mechanism 80 that changes the valve timing of the exhaust valve 38.

This variable valve mechanism 80 is equipped with a second hydraulic control valve 81. The second hydraulic control valve 81 is a linear solenoid valve equipped with an electromagnet, and the valve timing of the exhaust valve 38 is changed by changing the second excitation current I2, which is the excitation current supplied to this electromagnet. In addition, a second current detection circuit 82 that detects the second excitation current I2 flowing through the electromagnet is connected to the electromagnet of the second hydraulic control valve 81.

The intake passage 35 is provided with an air flow meter 39 that detects the intake flow rate GA, which is the flow rate of the intake air flowing therethrough, and a throttle valve 40, which is a valve for adjusting the intake flow rate. The internal combustion engine 10 also provides each cylinder 30 with a fuel injection valve 41 that injects fuel into the cylinder 30. Each cylinder 30 is also provided with an ignition device 42 that ignites the mixture of the intake air introduced through the intake passage 35 and the fuel injected by the fuel injection valve 41 by spark discharge. Meanwhile, the exhaust passage 37 is provided with a catalytic device 43 for purifying the exhaust gas.

<Various processes performed by the control device>
The control device 23 receives detection signals from the crank angle sensor 34, the air flow meter 39, the first current detection circuit 62, the second current detection circuit 82, and the like. The control device 23 also calculates the engine speed NE from the detection signal from the crank angle sensor 34. When the crankshaft 33 rotates in the reverse direction relative to the rotation direction during engine operation, the control device 23 sets the sign of the engine speed NE to a negative value. That is, the engine speed NE during reverse rotation becomes a negative value. The control device 23 controls the operation of the internal combustion engine 10 through the opening control of the throttle valve 40, the fuel injection control of the fuel injection valve 41, the ignition control of the ignition device 42, and the like. The control device 23 also controls the discharge amount of the oil pump 60 through the energization control of the first hydraulic control valve 61. In addition, the control device 23 controls the valve timing of the intake valve 36 through current control of the variable valve mechanism 70 , and controls the valve timing of the exhaust valve 38 through current control of the second hydraulic control valve 81 .

The control device 23 switches between an HEV (Hybrid Electric Vehicle) driving mode, in which the internal combustion engine 10 is operated, and an EV (Electric Vehicle) driving mode, in which the internal combustion engine 10 is stopped, depending on the driving conditions.

In the EV driving mode, the operation of the internal combustion engine 10 is stopped, the clutch 14 is disengaged, and the vehicle is driven by the power of the electric motor 15 .
In the HEV driving mode, the internal combustion engine 10 is operated and the clutch 14 is engaged, and the vehicle travels using the power of the internal combustion engine 10. In the HEV driving mode, the electric motor 15 is operated to perform driving assistance or the electric motor 15 is operated to perform regenerative power generation depending on the driving conditions of the vehicle.

The control device 23 automatically stops the internal combustion engine 10 when switching from the HEV driving mode to the EV driving mode. Note that the control device 23 also automatically stops the internal combustion engine 10 when it is possible to stop the operation of the internal combustion engine 10 when the vehicle stops with the HEV driving mode selected. The control device 23 also automatically restarts the internal combustion engine 10 when switching from the EV driving mode to the HEV driving mode.

When an automatic stop of the internal combustion engine 10 is requested, the control device 23 stops the combustion of the internal combustion engine 10 while keeping the clutch 14 engaged, and performs stop position control. This stop position control is a control that stops the piston 31 at a specified target position (for example, a position suitable for the next automatic restart) by driving the electric motor 15 to change the phase of the crankshaft 33. Note that when this stop position control is completed, the clutch 14 is released.

The control device 23 also performs a wire break diagnosis process to diagnose the first hydraulic control valve 61 and the second hydraulic control valve 81 for the presence or absence of a wire break while the hydraulic control valves are energized. The wire break diagnosis process is described below.

The control device 23 sets a target hydraulic pressure for the first hydraulic control valve 61 based on the target discharge amount of the oil pump 60, and calculates a target excitation current It1 corresponding to the target hydraulic pressure. Then, power is supplied to the electromagnet of the first hydraulic control valve 61 so that a current equivalent to the target excitation current It1 flows through the electromagnet. While the first hydraulic control valve 61 is energized, the control device 23 performs the above-mentioned disconnection diagnosis process. In this disconnection diagnosis process, the target excitation current It1 is compared with the above-mentioned first excitation current I1. If the target excitation current It1 and the first excitation current I1 are equal, it is determined that the first hydraulic control valve 61 does not have a disconnection. On the other hand, if the first excitation current I1 is "0" even though the first hydraulic control valve 61 is energized, it is determined that the first hydraulic control valve 61 has a disconnection.

Similarly, the control device 23 sets a target hydraulic pressure for the second hydraulic control valve 81 based on the target valve timing of the exhaust valve 38, and calculates a target excitation current It2 corresponding to the target hydraulic pressure. Then, power is supplied to the electromagnet of the second hydraulic control valve 81 so that a current equivalent to the target excitation current It2 flows through the electromagnet. While the second hydraulic control valve 81 is energized, the control device 23 performs the above-mentioned disconnection diagnosis process. In this disconnection diagnosis process, the target excitation current It2 is compared with the above-mentioned second excitation current I2. If the target excitation current It2 and the second excitation current I2 are equal, it is determined that the second hydraulic control valve 81 does not have a disconnection. On the other hand, if the second excitation current I2 is "0" even though the second hydraulic control valve 81 is energized, it is determined that the second hydraulic control valve 81 has a disconnection.

Furthermore, the control device 23 executes the process shown in FIG. 3 in order to reduce the power consumption of the vehicle.
3 shows the procedure of the process executed at each predetermined cycle by the control device 23. In the following, the step number of each process will be represented by a number preceded by the letter "S."

In the series of processes shown in FIG. 3, the control device 23 determines whether or not there is a request to execute the automatic stop described above (S100). If it is determined that there is a request to execute the automatic stop (S100: YES), the control device 23 determines whether or not the current engine speed NE is equal to or less than "0" (S110). If it is determined that the engine speed NE is equal to or less than "0" (S110: YES), the control device 23 executes a power supply stop process to stop the power supply to the first hydraulic control valve 61 and the second hydraulic control valve 81 (S120), and temporarily ends this process.

On the other hand, if the results of the above S100 and S110 processes are negative, the control device 23 permits the passage of current to the first hydraulic control valve 61 and the second hydraulic control valve 81 (S130) and temporarily terminates this process.

<Action and Effects>
The operation and effects of this embodiment will be described.
3, when the conditions that an automatic stop is requested (S100: YES) and the engine speed NE is equal to or less than "0" (S110: YES) are satisfied, a current supply cut process is executed (S120). Since the current supply cut process is executed to stop the current supply to the first hydraulic control valve 61 and the second hydraulic control valve 81, it is possible to reduce power consumption during the automatic stop of the internal combustion engine 10.

(1-2) If the conditions for executing the power cut process include the condition "there is a request to execute an automatic stop" but do not include the condition "the engine speed NE is equal to or less than 0", there is a concern that the following problems may occur.

In other words, immediately after a request to execute an automatic stop is made, the crankshaft 33 is still rotating and the engine speed NE is not "0". Therefore, if the condition "engine speed NE is equal to or less than "0"" is not included, the power supply stop process will be executed while the crankshaft 33 is still rotating.

During the period between when the automatic stop is requested and when the engine speed NE becomes "0", automatic restart of the internal combustion engine 10 may be initiated at the request of the vehicle driver or the like. In this case, if the power supply cut-off process is being executed, power is supplied to the first hydraulic control valve 61 and the second hydraulic control valve 81 in conjunction with the automatic restart, and this may result in a slower rise in hydraulic pressure compared to when the power supply cut-off process is not being executed.

In this regard, in this embodiment, the conditions for executing the de-energization process include the condition that the engine speed NE is equal to or less than 0. Therefore, the de-energization process is not executed from when the execution of the automatic stop is requested until the engine speed NE becomes 0. This makes it possible to avoid a slow rise in hydraulic pressure in the above-mentioned situation.

(1-3) If the conditions for executing the power cut process include the condition that the engine speed NE is equal to or less than 0, but do not include the condition that there is a request to execute an automatic stop, there is a concern that the following problems may occur.

In other words, the condition that "the engine speed NE is equal to or less than 0" may be satisfied not only during an automatic stop, but also when the engine stalls or there is an abnormality in the internal combustion engine 10. Therefore, if the condition that "there is a request to execute an automatic stop" is not included, there is a risk that the power supply cut-off process will be erroneously executed when the engine stalls or there is an abnormality in the internal combustion engine 10.

In this regard, in this embodiment, the conditions for executing the power supply stop process include the condition that "there is a request to execute an automatic stop." Therefore, the power supply stop process is executed when the engine operation is stopped due to an automatic stop. Therefore, it is possible to avoid the power supply stop process being executed erroneously in the above-mentioned situation.

(1-4) When the above-mentioned stop position control is executed, the crankshaft 33 of the internal combustion engine 10 may be rotated in reverse by the electric motor 15, causing the engine speed NE to become a negative value. In this regard, the execution condition for the above-mentioned power supply stop processing includes the condition that the engine speed NE is equal to or less than 0. Therefore, the above-mentioned power supply stop processing can be executed even when the crankshaft 33 is rotating in reverse due to the execution of the stop position control.

Second Embodiment
Hereinafter, a second embodiment of the vehicle control device will be described with reference to FIG.
The control device 23 of this embodiment is configured to execute the process shown in Fig. 4 at predetermined intervals in addition to the process shown in Fig. 3, and this is the only point that differs from the first embodiment. The process shown in Fig. 4 will be described below.

When the process shown in FIG. 4 is started, the control device 23 determines whether or not the first hydraulic control valve 61 and the second hydraulic control valve 81 are de-energized (S200). In the process of S200, the control device 23 makes a positive determination if the process of S120 shown in FIG. 3 is being executed.

When it is determined that the first hydraulic control valve 61 and the second hydraulic control valve 81 are not energized (S200: YES), the control device 23 determines whether the automatic stop time Ts is equal to or greater than a preset judgment value Tsref (S210). The automatic stop time Ts is the time that has elapsed since a request to execute an automatic stop is made, and is measured by the control device 23. In addition, as the judgment value Tsref, for example, a value that can determine that the automatic stop time Ts has become longer to a certain extent is preset.

When it is determined that the automatic stop time Ts is equal to or greater than the judgment value Tsref (S210: YES), the control device 23 temporarily energizes the first hydraulic control valve 61 and the second hydraulic control valve 81 (S220). In this temporary energization in S220, power is supplied in a pulsed manner to each electromagnet of the first hydraulic control valve 61 and the second hydraulic control valve 81. That is, the minimum excitation current Imi (e.g., several hundred mA) required to execute the above-mentioned disconnection diagnosis process is set as the target excitation current It1, It2. Then, the minimum excitation current Imi is supplied to each electromagnet of the first hydraulic control valve 61 and the second hydraulic control valve 81 only for the minimum diagnosis time Tdia (e.g., several hundred ms) required to execute the disconnection diagnosis process. In this way, while the minimum excitation current Imi is being supplied to each electromagnet of the first hydraulic control valve 61 and the second hydraulic control valve 81, the first hydraulic control valve 61 and the second hydraulic control valve 81 are in a conducting state, and the above-mentioned disconnection diagnosis process is executed.

When the control device 23 has finished the process of S220 or when a negative determination is made in the processes of S200 and S210, the control device 23 temporarily ends the series of processes shown in FIG.
<Action and Effects>
The operation and effects of this embodiment will be described.

(2-1) As shown in FIG. 4, even when the above-mentioned de-energization process is being performed, the process of S220 is executed, so that the first hydraulic control valve 61 and the second hydraulic control valve 81 are temporarily energized. Therefore, the above-mentioned open circuit diagnosis process can be performed while the internal combustion engine 10 is automatically stopped.

<Example of change>
The above-described embodiments may be modified as follows: The embodiments and the following modifications may be combined with each other to the extent that no technical contradiction occurs.

The process of S120 shown in FIG. 3 may be executed for only one of the first hydraulic control valve 61 and the second hydraulic control valve 81.
The process of S220 shown in FIG. 4 may be executed for only one of the first hydraulic control valve 61 and the second hydraulic control valve 81.

- A hydraulic variable valve mechanism equipped with a hydraulic control valve may be applied as the variable valve mechanism of the intake valve 36. In this case, too, by executing the various controls and processes described above on the hydraulic control valve equipped in the variable valve mechanism of the intake valve 36, it is possible to obtain the same effects and advantages as those of the respective embodiments.

The device having the hydraulic control valve may be a device other than the variable displacement oil pump 60 or the hydraulic variable valve mechanism 80.
Although the first hydraulic control valve 61 and the second hydraulic control valve 81 are linear solenoid valves, other valves that are operated by receiving an electric power supply may be used.

Instead of the stepped automatic transmission 19, a continuously variable automatic transmission may be used.
The hybrid system of the vehicle is not limited to the system shown in FIG. 1 and may be another system.

Even in the case of a vehicle that only has an internal combustion engine as a driving source for traveling, if the vehicle performs, for example, idle stop control, the internal combustion engine will be automatically stopped. Therefore, the above embodiments and modifications may be applied to vehicles that only have an internal combustion engine.

LIST OF SYMBOLS 10...internal combustion engine 14...clutch 15...electric motor 17...inverter 18...torque converter 19...automatic transmission 20...lock-up clutch 22...hydraulic control unit 23...control device 30...cylinder 31...piston 33...crankshaft 35...intake passage 36...intake valve 37...exhaust passage 38...exhaust valve 41...fuel injector 42...ignition device 60...oil pump 61...first hydraulic control valve 62...first current detection circuit 70...variable valve mechanism 80...variable valve mechanism 81...second hydraulic control valve 82...second current detection circuit

Claims (2)

A control device for a vehicle that automatically stops and automatically restarts an internal combustion engine having a hydraulic control valve and controls a current supply state to the hydraulic control valve,
a de-energization process for deenergizing the hydraulic control valve when a request for executing the automatic stop is received and the engine speed of the internal combustion engine is equal to or lower than 0 ;
a wire break diagnosis process for determining whether or not the hydraulic control valve has a wire break while the hydraulic control valve is energized;
a process of temporarily energizing the hydraulic control valve during the execution of the de-energization process;
Vehicle control device. A control device for a vehicle that automatically stops and automatically restarts an internal combustion engine having a hydraulic control valve and controls a current supply state to the hydraulic control valve,
the vehicle is a hybrid vehicle including the internal combustion engine and an electric motor as drive sources for traveling,
when a request for executing the automatic stop is received and the engine speed of the internal combustion engine is equal to or less than 0, a current supply stop process is executed to stop current supply to the hydraulic control valve ;
During the automatic stop, a stop position control is performed to drive the electric motor and stop the piston of the internal combustion engine at a specified target position.
Vehicle control device.

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