Vehicle control device

Abstract

To provide a vehicular control apparatus capable of improving accuracy in identifying a cylinder.SOLUTION: A control apparatus, of a vehicle that includes, as power sources, an engine and a generator motor, includes: an estimation part for estimating engine torque from a control state of the generator motor; an angle calculation part for calculating a resolver angle from an output signal of a resolver that detects a rotation angle of the generator motor; and a cylinder identification part for obtaining a resolver angle calculated by the angle calculation part when engine torque estimated by the estimation part becomes smaller than a predetermined reference value; and identifying a cylinder at a compression process on the basis of the calculated resolver angle.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a control device for a vehicle. [Background technology]

[0002] The control device of the hybrid vehicle described in Patent Document 1 obtains fluctuations in the rotation speed of the generator motor from an electrical signal of a resolver, and identifies the cylinder of the engine from the fluctuations in the rotation speed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-90915 Summary of the Invention [Problem to be solved by the invention]

[0004] However, fluctuations in rotation speed are caused by a wide range of factors other than the torque generated by the engine, such as changes in the speed of reciprocating inertia caused by the engine piston and the control torque of the generator motor. For this reason, when cylinders are identified based on rotation speed fluctuations, as in the control device of Patent Document 1, there is a problem that errors are large and the identification accuracy is insufficient. Furthermore, the control device of Patent Document 1 identifies cylinders based on the number of rotation speed drops, so it cannot identify cylinders based on the number of poles of the resolver. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a vehicle control device that includes an engine and a generator motor as power sources, and that includes: an estimation unit that estimates engine torque from a control state of the generator motor; an angle calculation unit that calculates a resolver angle from an output signal of a resolver that detects a rotation angle of the generator motor; and a cylinder discrimination unit that acquires the resolver angle calculated by the angle calculation unit when the engine torque estimated by the estimation unit falls below a predetermined reference value, and discriminates a cylinder that is in a compression stroke based on the resolver angle. According to this embodiment, a resolver for controlling the generator motor is used to perform cylinder discrimination based on the resolver angle, thereby improving discrimination accuracy regardless of the number of poles of the resolver. This in turn improves generator motor efficiency and fuel economy. Furthermore, since there is no need to separately provide an engine crank angle sensor or cylinder discrimination sensor for cylinder discrimination, additional costs can be reduced. Low fuel consumption and low cost are possible. (2) In the vehicle control device of the above aspect, the reference value of the engine torque may be variable depending on the operating state of the engine. According to this aspect, it is possible to improve the accuracy of cylinder discrimination. (3) In the vehicle control device of the above aspect, the reference value of the engine torque may be determined from a three-dimensional map based on the throttle opening and the engine speed. (4) In the vehicle control device of the above aspect, when a start request for requesting the start of the engine is received, the cylinder discrimination unit may execute discrimination of the cylinder. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a block diagram showing a configuration of a vehicle according to a first embodiment of the present disclosure. [Figure 2] FIG. 4 is a diagram for explaining the correspondence relationship between engine torque, resolver angle, and crank angle over time when the engine is started. [Figure 3] 4 is a flowchart showing a control procedure executed by the PCU when starting the engine. [Figure 4] FIG. 4 is a diagram showing changes in engine torque when the throttle opening degree is different. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. Implementation: A1.Vehicle configuration: 1 is a block diagram showing the configuration of a vehicle 1 according to a first embodiment of the present disclosure. In this embodiment, the vehicle 1 is an electric vehicle configured as a hybrid car equipped with a generator motor 12 and an engine 11 as driving power sources.

[0009] The vehicle 1 is equipped with a hybrid system 2. The hybrid system 2 includes an engine (E / G) 11, a generator motor (MG1) 12, a drive motor (MG2) 13, a battery 14, and a PCU (Power Control Unit) 15. The PCU 15 corresponds to a control device of the vehicle 1.

[0010] The engine 11 is a well-known internal combustion engine, such as a three-cylinder, four-stroke gasoline engine. The number of cylinders in the engine may be two, four, five or more. The operating state (running state, stopped state) of the engine 11 is controlled by a PCU 15, which will be described later. The engine torque Te [Nm], which is the output torque of the engine 11, is controlled by controlling a throttle actuator, an injector, an ignition device, and the like provided in the engine 11. The generator motor 12 is, for example, a permanent magnet synchronous motor. The generator motor 12 generates torque by receiving a supply of electric power from a battery system (not shown).

[0011] The crankshaft 21 of the engine 11 and the motor shaft 22 of the generator motor 12 are connected via a meshing mechanism 23 that transmits power by meshing teeth. This allows power to be transmitted between the crankshaft 21 and the motor shaft 22. Note that the engine 11 and the generator motor 12 only need to be mechanically coupled, and may or may not have gears.

[0012] The drive motor 13 is, for example, a permanent magnet synchronous motor that is larger than the generator motor 12. The motor shaft of the drive motor 13 is connected to a drive system 16 of the vehicle 1. The power of the drive motor 13 is transmitted to drive wheels 17 via the drive system 16. The battery 14 is an assembled battery that combines multiple secondary batteries (for example, lithium ion batteries).

[0013] The PCU 15 is a unit for controlling the driving of the generator motor 12 and the drive motor 13. The PCU 15 acquires information from various devices and sensors mounted on the vehicle 1. Specifically, the PCU 15 acquires a signal corresponding to the motor rotation speed from a resolver 33 installed on the generator motor 12, a current value from a motor current sensor (not shown), and a voltage value from a motor voltage sensor (not shown). In addition, the PCU 15 acquires the accelerator opening, brake pedal force, throttle opening, vehicle speed, shift position, etc. The vehicle 1 is equipped with an HV-ECU 31 and an E / G-ECU 32 as ECUs (Electronic Control Units) for the hybrid system 2.

[0014] A microcomputer (microcontroller unit) is built into the PCU 15, the HV-ECU 31, and the E / G-ECU 32. The microcomputer includes, for example, a CPU, a nonvolatile memory such as a flash memory, and a volatile memory such as a dynamic random access memory (DRAM). The PCU 15, the HV-ECU 31, and the E / G-ECU 32 are connected to each other so as to enable bidirectional communication using a controller area network (CAN) communication protocol (hereinafter referred to as "CAN communication").

[0015] The HV-ECU 31 is an ECU that performs overall control of the hybrid system 2, and receives various information from the PCU 15 and the E / G-ECU 32 via CAN communication, and transmits motor control commands and engine control commands to the PCU 15 and the E / G-ECU 32, respectively.

[0016] A resolver 33 is connected to the PCU 15. The resolver 33 is attached to the generator motor 12, and outputs a change in the rotation angle of the motor shaft 22 of the generator motor 12 as a change in two-phase AC voltage. The resolver 33 is provided with an R / D (resolver / digital) converter that converts the analog signal of the two-phase AC voltage output by the resolver 33 into a digital signal, and the digital signal output from the R / D converter is input as a resolver signal to the microcomputer of the PCU 15 as a signal required for motor control.

[0017] The microcomputer of the PCU 15 controls the driving of the generator motor 12 via the MG1 inverter and the driving of the drive motor 13 via the MG2 inverter in accordance with a motor control command sent from the HV-ECU 31 .

[0018] A crank angle sensor 34 mounted on the crankshaft 21 is connected to the E / G-ECU 32. The crank angle sensor 34 outputs a detection signal corresponding to the rotation angle of the crankshaft 21. The detection signal from the crank angle sensor 34 is input to the microcomputer of the E / G-ECU 32. The microcomputer of the PCU 15 controls the operation of the electronic throttle valve, the injectors, and the spark plugs, such as the amount and timing of fuel injection by the injectors, in accordance with engine control commands transmitted from the HV-ECU 31.

[0019] The PCU 15 and the E / G-ECU 32 perform control in accordance with motor control commands and engine control commands from the HV-ECU 31, so that when the engine 11 is started, the DC power output from the battery 14 is boosted by the converter, the boosted DC power is converted to AC power by the MG1 inverter, and the AC power is supplied to the generator motor 12. This causes the generator motor 12 to operate, and the engine 11 is motored by the generator motor 12. When the rotation speed of the crankshaft 21 of the engine 11 has increased to the rotation speed required for starting due to motoring, the electronic throttle valve, injector, and spark plug are controlled, and the engine 11 is started.

[0020] The PCU 15 includes, as its functional units, an estimation unit 41, an angle calculation unit 42, and a cylinder discrimination unit 43. Each of the functional units 41, 42, and 43 is implemented by the CPU reading and executing a program stored in memory. The estimation unit 41 estimates the engine torque Te from the control state of the generator motor 12. The angle calculation unit 42 calculates the resolver angle θ from the output signal of the resolver 33. The cylinder discrimination unit 43 obtains the resolver angle θcomp when the engine torque Te estimated by the estimation unit 41 falls below a predetermined reference value Tcomp, estimates the crank angle based on the resolver angle, and discriminates the cylinder in the compression stroke. The cylinder discrimination unit 43 performs the cylinder discrimination when it receives a start request to start the engine 11.

[0021] A2. Engine start control: Next, the control executed by PCU 15 at engine start will be described with reference to Figs. 2 to 4. Fig. 2 is a diagram for explaining the correspondence relationship between engine torque, resolver angle, and crank angle over time at engine start. In Fig. 2, the upper part shows the time change of engine torque Te, and the middle part shows the time change of resolver angle θ. Furthermore, the lower part of Fig. 2 shows the time change of an estimated crank angle.

[0022] In the example shown in Figure 2, the gear ratio between the generator motor 12 and the engine 11 is 1:1, and the engine 11 is a three-cylinder, four-stroke engine. The resolver has two poles (one rotation is 360° x 2). The crank angle at the ignition TDC (Top Dead Center) of the first cylinder is 0°, and the resolver angle at that time is also 0°.

[0023] The engine torque Te can be estimated from the state of motor control and is expressed by the following equation (1). Te=-Tmg+I×dθeng / dt ···(1) In equation (1), Tmg is the motor torque, calculated from the motor current and motor voltage. I is the moment of inertia around the engine shaft. dθeng / dt is the change in engine speed per unit time. The change in engine speed is calculated from the change in resolver speed.

[0024] In this embodiment, the generator motor 12 detects the negative torque during the engine compression stroke, and the cylinder number during the compression stroke is identified from the resolver angle θcomp at that time. As shown in FIG. 2, the resolver angle θcomp is calculated when the engine torque becomes smaller than a predetermined reference value Tcomp. For convenience, the reference value Tcomp is shown as the same line, i.e., the same value, at multiple calculation timings in FIG. 2, but it is variable depending on the operating state of the engine 11. The reference value Tcomp is determined from a pre-stored three-dimensional map with the throttle opening and engine speed as axes. The reference value Tcomp does not have to be variable, and may instead be a fixed value.

[0025] As shown in the middle and bottom rows of FIG. 2, if the resolver angle θcomp is within the range of 0°±A°, the compression stroke of cylinder 2 is determined, and the crank angle is estimated to be 180°. Then, at a timing when the crank angle is 240°, as shown by "#2 Ignition" in FIG. 2, cylinder 2 is ignited. If the resolver angle θcomp is within the range of 120°±A°, the compression stroke of cylinder 3 is determined, and the crank angle is estimated to be 60°. Then, at a timing when the crank angle is 120°, as shown by "#3 Ignition" in FIG. 2, cylinder 3 is ignited. If the resolver angle θcomp is within the range of 240°±A°, the compression stroke of cylinder 1 is determined, and the crank angle is estimated to be 300°. Then, at a timing when the crank angle is 300°, as shown by "#1 Ignition" in FIG. 2. In the above, the value of "A" indicates a margin, and is set to, for example, about 30°.

[0026] 3 is a flowchart showing a control procedure executed by the PCU 15 when starting the engine. As shown in FIG. 3, in S101, it is determined whether or not there is an engine start request. For example, if a predetermined condition is met, such as the ignition switch being turned on, it can be determined that there is an engine start request. If the predetermined condition is not met, it can be determined that there is no engine start request.

[0027] If it is determined that there is no engine start request (S101: No), the process of S101 is repeatedly executed until there is an engine start request. If it is determined that there is an engine start request (S101: Yes), the process proceeds to S102, where the engine 11 is motored by the generator motor 12. For example, the engine speed at this time is 1500 rpm. At this time, the engine torque Te is sensed.

[0028] When motoring is performed in S102, the resolver angle θcomp is calculated in S103 when the estimated engine torque becomes smaller than a predetermined reference value Tcomp. Then, in S104, the cylinder in the compression stroke is identified based on the resolver angle θcomp, and it is determined which cylinder is in the compression stroke. Then, in S105, the crank angle is estimated. Then, in S106, fuel injection and ignition are started for the identified cylinder. Note that the details of cylinder identification and crank angle estimation according to the specific value of the resolver angle θcomp are as described above. This completes the processing routine. As described above, after cylinder identification at engine start, ignition is repeatedly performed every 240° of crank angle change during subsequent operation.

[0029] (1) According to the first embodiment, the motor control resolver 33 is used to perform cylinder identification based on the resolver angle θcomp when the engine torque Te becomes smaller than the reference value Tcomp. Therefore, compared to a case where a resolver with one pole is used to identify the cylinder of the engine 11 based on fluctuations in the motor rotation speed, as described in Patent Document 1, for example, errors are reduced and identification accuracy can be improved even when the number of poles of the resolver changes. Consequently, motor efficiency and fuel economy can be improved. Furthermore, since there is no need to separately provide an engine crank angle sensor or a cylinder identification sensor for cylinder identification, additional costs can be reduced. This allows for low fuel consumption and low cost.

[0030] (2) According to the first embodiment, in step S103, the predetermined reference value Tcomp is variable depending on the operating state. Fig. 4 is a diagram showing changes in engine torque when the throttle opening is different. In Fig. 4, the solid line indicates engine torque Ts in an operating state where the throttle opening is relatively small and the intake pressure is low, and the dashed line indicates engine torque Tb in an operating state where the throttle opening is relatively large and the intake pressure is high.

[0031] As shown in Fig. 4, the engine torque Tb fluctuates more when the throttle is open wide than when the engine torque Ts is open narrow. When the same reference value Tcomp is used to determine whether the torque is decreasing, the engine torque Tb when the throttle is open wide falls below the reference value Tcomp sooner than the engine torque Ts when the throttle is open narrow. In other words, if the reference value Tcomp is set to a fixed value, a determination error may occur. Although the resolver angle θcomp is determined with a certain range (θcomp±A) in S104, the greater the number of poles of the resolver 33, the more accurate the determination of the resolver angle θcomp becomes.

[0032] In the first embodiment, a fixed reference value Tcomp is not used, but the reference value Tcomp is determined according to the operating state from a three-dimensional map based on the throttle opening and engine speed. For example, in the example of Fig. 4, when the throttle opening is large, a smaller value is set as the reference value Tcomp than when the throttle opening is small. Then, by comparing with this reference value Tcomp, it is determined whether the engine torque Te has fallen below the reference value Tcomp, thereby improving the accuracy of cylinder discrimination.

[0033] B. Other Embodiments: (B1) In the first embodiment, when the engine is started, the generator motor 12 detects the negative torque during the compression stroke of the engine, and the cylinder number during the compression stroke is identified from the resolver angle θcomp at that time. For example, in a vehicle having a VVT (Variable Valve Timing) mechanism, the crank angle sensor and cam angle sensor for VVT control function as cylinder identification sensors. In such a vehicle, this may be used for fail-safe control when the cylinder identification sensor fails, rather than at the time of starting.

[0034] 3 can be replaced with a process for determining whether the cylinder discrimination sensor has failed. With this configuration, even if the cam angle sensor has failed, the vehicle can be driven to the nearest repair shop in failure mode, for example, without immediately stopping the engine 11.

[0035] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features in each embodiment corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0036] 1...vehicle, 2...hybrid system, 11...engine, 12...generator motor, 13...drive motor, 14...battery, 15...PCU (control unit), 16...drive system, 17...drive wheels, 21...crankshaft, 22...motor shaft, 23...engagement mechanism, 33...resolver, 34...crank angle sensor, 41...estimation unit, 42...angle calculation unit, 43...cylinder discrimination unit

Claims

1. A control device for a vehicle including an engine and a generator motor as power sources, an estimation unit that estimates engine torque from a control state of the generator motor; an angle calculation unit that calculates a resolver angle from an output signal of a resolver that detects a rotation angle of the generator motor; a cylinder discrimination unit that acquires the resolver angle calculated by the angle calculation unit when the engine torque estimated by the estimation unit falls below a predetermined reference value, and discriminates a cylinder that is in a compression stroke based on the resolver angle; A vehicle control device comprising:

2. 2. The vehicle control device according to claim 1, wherein the reference value of the engine torque is variable depending on an operating state of the engine.

3. 3. The vehicle control device according to claim 2, wherein the reference value of the engine torque is determined from a three-dimensional map based on a throttle opening and an engine speed.

4. 3. The vehicle control device according to claim 1, wherein the cylinder discrimination unit executes the cylinder discrimination when a start request for requesting the engine to be started is received.

Images