JP7692666B2 - Hybrid Control System - Google Patents

Description

The present invention relates to a hybrid control system.

Vehicles that use a hybrid system in their drivetrain, known as hybrid vehicles (HVs), are known in the past. For example, in a series-type hybrid vehicle, the engine's power is converted to electricity by a generator motor (generator), the drive motor is driven by the electricity, and the power of the drive motor is transmitted to the drive wheels.

The engine and the generator motor are connected via a meshing mechanism such as gears or splines. Therefore, when the engine is started or during light load operation, torque fluctuations (reversals) that cross zero torque occur in the meshing mechanism, causing a gear rattle noise due to changes in the meshing state of the meshing mechanism. As a measure to reduce this gear rattle noise, it has been proposed to apply a compensation torque synchronized with the torque fluctuations of the engine from the generator motor to the meshing mechanism (see, for example, Patent Document 1).

To calculate engine torque fluctuations, it is necessary to detect the engine crank angle. Since detecting the crank angle is necessary to control the engine, a crank angle sensor that outputs a pulse signal each time the crankshaft rotates a certain angle is connected to the engine ECU (Electronic Control Unit) that controls the engine. However, a crank angle sensor is not connected to the motor ECU that controls the generator motor, and the pulse signal from the crank angle sensor is not input.

In order to detect the crank angle with the motor ECU, for example, a configuration has been proposed in which the engine ECU and the motor ECU are connected with a serial communication line and a parallel communication line, the engine ECU calculates the crank angle and crank angular velocity from the output signal of the crank angle sensor, and transmits the calculated crank angle and crank angular velocity from the engine ECU to the motor ECU via serial communication, and transmits a communication start signal from the engine ECU to the motor ECU via parallel communication (see, for example, Patent Document 2). The motor ECU measures the time from receiving the communication start signal to completing reception of the crank angle and crank angular velocity, and estimates the current crank angle by multiplying the measured time by the received crank angular velocity and adding the product to the received crank angle.

JP 2021-054330 A JP 2009-292168 A

However, such a configuration requires a dedicated communication line (serial communication line, parallel communication line) to connect the engine ECU and the motor ECU, as well as an input/output circuit for communication via that communication line, resulting in increased costs.

The object of the present invention is to provide a hybrid control system that allows the motor control device to estimate the engine crank angle with high resolution and precision without increasing costs by providing a dedicated communication line for communication with the engine control device.

To achieve the above object, the hybrid control system according to the present invention is a system mounted on a vehicle having a meshing mechanism between the crankshaft of the engine and the rotating shaft of the generator motor, which transmits power by meshing teeth, a crank angle sensor that outputs a crank pulse signal synchronized with the rotation of the crankshaft, and a resolver that outputs a resolver signal that changes according to the rotation angle of the rotating shaft, and controls the engine and the generator motor. The system includes an engine control device that calculates the engine crank angle from the crank pulse signal and controls the engine using the calculated crank angle, and a motor control device that calculates the resolver angle from the resolver signal and controls the generator motor using the calculated rotation angle. The engine control device and the motor control device are connected to each other so as to be able to communicate with each other via an in-vehicle network built in the vehicle. The motor control device receives the crank angle calculated by the engine control device from the engine control device, learns the relationship between the crank angle and the resolver angle at the pulse interrupt time when the pulse edge of the crank pulse signal is input to the engine control device, and estimates the crank angle at the current time based on the learned relationship and the resolver angle.

According to this configuration, a meshing mechanism is interposed between the engine crankshaft and the rotating shaft of the generator motor. Therefore, when torque fluctuations that cross zero torque occur in the meshing mechanism, such as when the engine is started, the meshing state of the meshing mechanism changes, causing teeth rattle noise. This teeth rattle noise can be reduced by applying a compensation torque from the generator motor to the meshing mechanism that is synchronized with the torque fluctuations of the engine.

The engine crank angle is required to calculate engine torque fluctuations. The crank pulse signal output by the crank angle sensor is input to the engine control device that controls the engine, and is not input to the motor control device that controls the generator motor. Therefore, the motor control device cannot calculate the crank angle from the crank pulse signal, and the crank angle calculated from the crank pulse signal by the engine control device is input to the motor control device.

The crank angle sensor typically outputs a crank pulse signal at intervals of 10° to 30°. In the engine control device, a pulse interrupt process occurs in response to the input of a pulse edge (rising edge or falling edge) of the crank pulse signal, and the crank angle is calculated from the crank pulse signal by this pulse interrupt process. Therefore, the crank angle at the pulse interrupt time when the pulse interrupt process occurs, i.e., the time when the crank pulse signal is input, can be calculated with high accuracy, but between pulse edges the crank angle must be calculated by interpolation, making it difficult to obtain an accurate crank angle.

Meanwhile, a resolver signal is input to the motor control device from a resolver with higher resolution than the crank angle sensor, and the motor control device calculates the resolver angle (motor rotation angle of the power generation motor) from the resolver signal in order to control the power generation motor. Since the resolver angle is correlated with the engine crank angle, if the relationship between the crank angle and resolver angle at the pulse interrupt time when the pulse interrupt processing occurs is known, it is possible to accurately estimate the crank angle from the resolver angle even between pulse edges of the crank pulse signal.

The motor control device receives the crank angle from the engine control device. The motor control device then learns the relationship between the crank angle and resolver angle at the pulse interrupt time, and estimates the crank angle at the current time based on that relationship and the resolver angle. This allows the motor control device to accurately estimate the engine crank angle with high resolution, without the increased costs that would be incurred by installing a dedicated communication line for communication between the motor control device and the engine control device.

As a result, the accuracy of the control that compensates for engine torque fluctuations with the compensation torque can be improved, and teeth rattle noise can be effectively reduced. This allows the set torque of the crankshaft damper to be reduced when a crankshaft damper is provided to dampen vibrations of the engine crankshaft, suppressing problems caused by energy loss and heat generation by the crankshaft damper. Furthermore, by reducing the set torque of the crankshaft damper, the variation and change over time of the torque of the crankshaft damper are reduced, and the vibrations of the crankshaft are effectively damped. In addition, the engine can be fired at a low rotation speed, improving the power generation response of the generator motor during rapid acceleration, and improving the acceleration response of the vehicle.

The engine control device may have a transmission buffer that temporarily stores the crank angle when transmitting it to the motor control device, and the motor control device may receive from the engine control device the pulse interrupt time and the transmission buffer update time at which the engine control device updated the transmission buffer, estimate a communication delay time due to communication between the engine control device and the motor control device from the time difference between the current time and the transmission buffer update time, use the estimated communication delay time to determine the elapsed time from the pulse interrupt time to the current time, obtain the resolver angle before the elapsed time from the current time as the resolver angle at the pulse interrupt time, and learn the relationship between the crank angle and the resolver angle at the pulse interrupt time.

This makes it possible to compensate for communication delays between the engine control device and the motor control device, enabling more accurate estimation of the engine crank angle.

The motor control device acquires the current time and the transmission buffer update time, calculates the time difference between the current time and the transmission buffer update time, and if the calculated time difference is greater than the currently held maximum value, updates the held maximum value with the time difference. If the calculated time difference is less than the currently held minimum value, updates the held minimum value with the time difference, subtracts the average value of the held maximum value and minimum value from the calculated time difference, and adds a preset expected value of the average value to the subtracted value, and the obtained value may be used as an estimate of the communication delay time.

This makes it possible to learn the steady-state communication delay time while eliminating the effects of variations in actual communication delays. As a result, it is possible to effectively learn the relationship between the crank angle and resolver angle at the pulse interrupt time, and based on this learned relationship, it is possible to accurately estimate the crank angle at the current time.

According to the present invention, the motor control device can estimate the engine crank angle with high resolution and precision without the increased costs that would be incurred by providing a dedicated communication line for communication with the engine control device.

1 is a block diagram showing a configuration of a vehicle equipped with a hybrid control system according to an embodiment of the present invention. FIG. 4 is a diagram for explaining a method of calculating a crank angle estimated value by the MG-ECU. FIG. 4 is a diagram for explaining symbols used in calculation of a damper torsional angle estimated value. The figure shows time-series data of the actual measured communication delay between the EFI-ECU and the MG-ECU. This shows time-series data of the value (Tdif) obtained by subtracting the transmission buffer update time from the current time.

The following describes in detail an embodiment of the present invention with reference to the attached drawings.

<Hybrid vehicle>
FIG. 1 is a block diagram showing the configuration of a hybrid vehicle 1 equipped with a hybrid control system according to an embodiment of the present invention.

The hybrid vehicle 1 employs a series hybrid system and is equipped with 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.

Engine 11 is, for example, a three-cylinder, four-stroke gasoline engine. Engine 11 is equipped with an electronic throttle valve for adjusting the amount of air intake into the combustion chamber, an injector (fuel injection device) for injecting fuel into the intake air, and a spark plug for generating an electrical discharge in the combustion chamber.

The generator motor 12 is, for example, a permanent magnet synchronous motor (PMSM).

The crankshaft 16 of the engine 11 and the motor shaft 17, which is the rotating shaft of the generator motor 12, are connected via a meshing mechanism 18 that transmits power by meshing teeth. The meshing mechanism 18 includes, for example, a male spline provided on one of the crankshaft 16 and the motor shaft 17, and a female spline provided on the other, and is a mechanism that enables power to be transmitted between the crankshaft 16 and the motor shaft 17 by meshing the teeth of the male spline with the teeth of the female spline.

In addition, a crankshaft damper 19 consisting of a rotary friction damper is attached to the crankshaft 16 of the engine 11 to reduce torsional and bending vibrations of the crankshaft 16.

The drive motor 13 is, for example, a permanent magnet synchronous motor that is larger than the generator motor 12. A motor shaft 21, which is the rotating shaft of the drive motor 13, is connected to a drive system 22 of the hybrid vehicle 1. The drive system 22 includes a differential gear, and the power of the drive motor 13 is transmitted to the differential gear, and is then distributed and transmitted from the differential gear to drive wheels 23, which consist of the left and right front wheels or rear wheels. This causes the left and right drive wheels 23 to rotate, and the hybrid vehicle 1 to move forward or backward.

Battery 14 is a battery pack made up of multiple secondary batteries. The secondary batteries are, for example, lithium-ion batteries. Battery 14 outputs, for example, DC power of approximately 200 to 350 V (volts).

The PCU 15 is a unit for controlling the driving of the generator motor 12 and the drive motor 13. Although not shown, the PCU 15 is equipped with an MG1 inverter, an MG2 inverter, and a converter.

The MG1 inverter is a three-phase voltage-type inverter that drives the generator motor 12, and has a configuration in which two IGBT (Insulated Gate Bipolar Transistor) series circuits are provided corresponding to each of the U, V, and W phases, and these series circuits are connected in parallel between the positive and negative wiring. The MG1 inverter converts DC power to AC power during power running of the generator motor 12, and supplies the AC power to the generator motor 12. The MG1 inverter also converts AC power generated by the generator motor 12 into DC power during regenerative operation (power generation operation) of the generator motor 12.

The MG2 inverter is a three-phase voltage-type inverter that drives the drive motor 13, and similar to the MG1 inverter, has a configuration in which two IGBT series circuits are provided corresponding to each of the U, V, and W phases, and these series circuits are connected in parallel between the positive and negative wiring. The MG2 inverter converts DC power to AC power during power running of the drive motor 13, and supplies the AC power to the drive motor 13. The MG2 inverter also converts AC power generated by the drive motor 13 into DC power during regenerative operation (power generation operation) of the drive motor 13.

When the generator motor 12 and the drive motor 13 are in powered operation, the converter boosts the DC power output from the battery 14 and supplies it to the MG1 inverter and the MG2 inverter, respectively. In addition, when the generator motor 12 and the drive motor 13 are in regenerative operation, the converter reduces the DC power output from the MG1 inverter and the MG2 inverter and supplies it to the battery 14.

The hybrid vehicle 1 is equipped with multiple ECUs (Electronic Control Units), each of which has a microcontroller that includes, for example, a CPU, a non-volatile memory such as a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory). The multiple ECUs are connected to enable two-way communication using the CAN (Controller Area Network) communication protocol.

The multiple ECUs include an HV-ECU 31, an EFI-ECU 32, and an MG-ECU 33. The HV-ECU 31 is a unit that provides overall control of the entire hybrid system, including the engine 11, the generator motor 12, and the drive motor 13. The EFI-ECU 32 is a unit that controls the engine 11. The MG-ECU 33 is a unit that controls the generator motor 12 and the drive motor 13, and is built into the PCU 15.

A crank angle sensor 34 is connected to the EFI-ECU 32. The crank angle sensor 34 outputs a crank pulse signal synchronized with the rotation of the crankshaft 16, for example, at intervals of 10° to 30° of the rotation angle of the crankshaft 16. The crank pulse signal is input from the crank angle sensor 34 to the EFI-ECU 32 as a signal required for engine control. The EFI-ECU 32 controls the operation of the electronic throttle valve, injectors, and spark plugs, such as the amount and timing of fuel injection by the injectors, according to engine control commands sent from the HV-ECU 31.

A resolver 35 having a high resolution of, for example, 10 to 16 bits (360°/1024 to 65536) is connected to the PCU 15. The resolver 35 is attached to the generator motor 12 and outputs the change in the rotation angle (motor rotation angle) of the motor shaft 17 of the generator motor 12 as a change in two-phase AC voltage. The resolver 35 is provided with an R/D (resolver/digital) converter that converts the analog signal of the two-phase AC voltage output by the resolver 35 into a digital signal, and the digital signal output from the R/D converter is input to the MG-ECU 33 as a resolver signal as a signal required for motor control. The MG-ECU 33 controls the drive of the generator motor 12 via the MG1 inverter and controls the drive of the drive motor 13 via the MG2 inverter according to the motor control command transmitted from the HV-ECU 31. The MG-ECU 33 also controls the step-up and step-down of the DC voltage by the converter as necessary.

When starting the engine 11 in the hybrid vehicle 1, power is supplied from the battery 14 to the generator motor 12, and the generator motor 12 is powered, so that the engine 11 is motored (cranked) by the generator motor 12. When the engine 11 speed increases to the speed required for firing due to motoring, the ignition plug of the engine 11 is sparked, and the engine 11 fires.

When the hybrid vehicle 1 is running, the drive motor 13 is powered and generates power. With the engine 11 stopped and the generator motor 12 not generating power, the drive motor 13 is driven by the output of the battery 14, causing the hybrid vehicle 1 to run as an EV (Electric Vehicle). Also, with the engine 11 in operation (firing) and the generator motor 12 in generating power (regenerative operation), the drive motor 13 is driven by the combined power of the output of the generator motor 12 (generated power) and the output of the battery 14, causing the hybrid vehicle 1 to run as an HV.

When the hybrid vehicle 1 decelerates, the drive motor 13 operates in regenerative mode, and the power transmitted from the drive wheels to the drive motor 13 is converted into AC power. At this time, the drive motor 13 acts as a resistance in the driving system, and this resistance acts as a braking force (regenerative braking force) that brakes the hybrid vehicle 1. At this time, the generated power of the drive motor 13 is supplied to the battery 14, thereby charging the battery 14.

<Crank angle estimation method>
Fig. 2 is a diagram for explaining a method of calculating the crank angle estimated value CAEST by the MG-ECU 33. Fig. 3 is a diagram for explaining symbols used in calculating the damper torsional angle estimated value DA.

As mentioned above, the meshing mechanism 18 is interposed between the crankshaft 16 of the engine 11 and the motor shaft 17 of the generator motor 12. Therefore, when the engine 11 is started or in light load operation, torque fluctuations that cross zero torque occur in the meshing mechanism 18, and the meshing state of the meshing mechanism 18 changes, generating gear rattle noise. To reduce this gear rattle noise, the MG-ECU 33 (PCU 15) controls the drive of the generator motor 12 so that the generator motor 12 provides the meshing mechanism 18 with a compensation torque synchronized with the torque fluctuations of the engine 11.

The crank angle of the engine 11 is required to calculate the torque fluctuation of the engine 11. When the EFI-ECU 32 receives (detects) a pulse edge (e.g., a rising edge) of the crank pulse signal from the crank angle sensor 34, a pulse interrupt process occurs, the time at that point is acquired as the pulse interrupt time Tp (step S101), and the pulse interrupt process is performed to calculate the crank angle EFICA (step S102). The crank angle EFICA is used for engine control by the EFI-ECU 32.

A transmission buffer is set in the volatile memory built into the microcomputer of the EFI-ECU 32 to temporarily store data to be transmitted to other ECUs. When the crank angle EFICA is calculated, the calculated crank angle EFICA and the pulse interrupt time Tp, which is the calculation start time of the crank angle EFICA, are stored in the transmission buffer. In addition, the time at that point in time, that is, the transmission buffer update time Ttxb at which the transmission buffer is updated by storing the pulse interrupt time Tp and the crank angle EFICA, is stored in the transmission buffer (step S103). Then, the pulse interrupt time Tp, crank angle EFICA, and transmission buffer update time Ttxb stored in the transmission buffer are transmitted to the MG-ECU 33 via CAN communication.

When the MG-ECU 33 receives data from the EFI-ECU 32, i.e., the pulse interrupt time Tp, the crank angle EFICA, and the transmission buffer update time Ttxb, the received data is stored in a volatile memory (hereinafter simply referred to as "memory") built into the microcomputer of the MG-ECU 33 (step S201).

The MG-ECU 33 also obtains the resolver angle RESA from the resolver signal from the resolver 35. The resolver angle RESA is stored in memory in a state in which the time at which it was obtained can be identified (step S202).

Furthermore, the MG-ECU 33 calculates an estimate of the torsion angle occurring in the crankshaft damper 19 (damper torsion angle estimate value) DA, and stores the calculated damper torsion angle estimate value DA in memory (step S203).

3, if the inertia, torque, and crank angle of the engine 11 are Ie, Te, and θe, the inertia, torque, and motor rotation angle of the generator motor 12 are Img, Tmg, and θmg, and the damper torsional spring constant and friction torque of the crankshaft damper 19 are K and Tf, respectively, then the torsional angle θd generated in the crankshaft damper 19 is θd=θmg-θe. Also, the torque (damper torque) Td of the crankshaft damper 19 is
and satisfies the following formula (2).

By eliminating the damper torque Td from equations (1) and (2) and rearranging the equations, the following equation (3) can be obtained.

The torsion angle θd occurring in the crankshaft damper 19 can be calculated from the previous value of the torsion angle θd and the condition of formula (3). Even if the previous value of the torsion angle θd is the current value of the torsion angle θd, if the condition of formula (3) is satisfied, the previous value of the torsion angle θd may be used as the current value of the torsion angle θd as it is. If the previous value of the torsion angle θd is used as the current value of the torsion angle θd, if the condition of formula (3) is not satisfied, the torsion angle θd should have changed from the previous value to a value that satisfies the condition of formula (3), so the previous value may be used as a value that satisfies formula (3). Specifically, the value of the right side or the left side of formula (3), whichever is closer to the previous value of the torsion angle θd, may be selected. The calculated torsion angle θd is stored in memory as the damper torsion angle estimated value DA in a state in which the time of calculation can be identified.

Then, the MG-ECU 33 acquires the current time Tnow (step S204). Then, the communication delay between the EFI-ECU 32 and the MG-ECU 33 is learned (step S205). The communication delay is defined as the time from when the transmission buffer is updated in step S103 until the MG-ECU 33 receives the data stored in the transmission buffer at that time and acquires the current time Tnow in step S204.

Figure 4 shows time series data of the actual measured communication delay between the EFI-ECU 32 and the MG-ECU 33.

The actual communication delay varies widely as shown in FIG. 4 because it is affected by differences in processing timing between the EFI-ECU 32 and the MG-ECU 33, and because a transmission wait time occurs when data with a higher priority than the data for calculating the crank angle estimate CAEST (pulse interrupt time Tp, crank angle EFICA, and transmission buffer update time Ttxb) is transmitted from the EFI-ECU 32. The maximum and minimum values of the actual communication delay are known from actual measurements.

Figure 5 is a graph showing the time change of the value Tdif, which is the current time Tnow minus the transmission buffer update time Ttxb. The EFI-ECU 32 and MG-ECU 33 each determine the time using their own clocks, and since these clocks are not synchronized, the graph slopes upwards compared to the graph shown in Figure 4 due to the relative clock error.

In learning communication delay, a value Tdif is calculated by subtracting the transmission buffer update time Ttxb from the current time Tnow, in other words, the time difference Tdif between the current time Tnow and the transmission buffer update time Ttxb. If the calculated time difference Tdif is greater than the currently held maximum value (hereinafter referred to as the "held maximum value") Tmax, the held maximum value Tmax is updated with the time difference Tdif. If the calculated time difference Tdif is less than the currently held minimum value (hereinafter referred to as the "held minimum value") Tmin, the held minimum value Tmin is updated with the time difference Tdif. Then, the average value Tcenter of the held maximum value Tmax and the held minimum value Tmin is calculated.

When the relative clock error is positive and the time difference Tdif tends to increase over time, the maximum retained value Tmax is updated more frequently, and when the relative clock error is negative and the time difference Tdif tends to decrease over time, the minimum retained value Tmin is updated more frequently. Therefore, a value Nud obtained by subtracting the number of updates to the minimum retained value Tmin from the number of updates to the maximum retained value Tmax is stored in memory, and as the value Nud increases, the maximum retained value Tmax and the minimum retained value Tmin increase over time, and as the value Nud decreases, the maximum retained value Tmax and the minimum retained value Tmin decrease over time.

In addition, when the difference between the maximum retained value Tmax and the minimum retained value Tmin becomes larger than the difference between the maximum and minimum values of the communication delay actually measured in advance, the update frequency of the maximum retained value Tmax and the minimum retained value Tmin decreases, and the deviation between the average value Tcenter of the maximum retained value Tmax and the minimum retained value Tmin and the average value of the maximum and minimum values of the communication delay actually measured in advance increases. Therefore, when the difference between the maximum retained value Tmax and the minimum retained value Tmin becomes larger than the predetermined value Trange, the maximum retained value Tmax and the minimum retained value Tmin are corrected so that the maximum retained value Tmax decreases over time and the minimum retained value Tmin increases over time until the difference between the maximum retained value Tmax and the minimum retained value Tmin becomes equal to or less than the value Trange.

The value Trange is set to a value equal to the difference between the maximum and minimum values of the communication delay actually measured in advance, or to a value slightly smaller than the difference between the maximum and minimum values of the communication delay actually measured in advance in order to increase the update frequency of the retained maximum value Tmax and the retained minimum value Tmin.

Then, the difference between the time difference Tdif and the average value Tcenter of the retained maximum value Tmax and the retained minimum value Tmin is taken as the difference between the time difference Tdif and the average value of the maximum and minimum values of the communication delay actually measured in advance, and the expected value Text of the average value Tcenter is added to this difference to estimate the communication delay estimated value Tdest. The expected value Text is set to a value close to the average value of the maximum and minimum values of the communication delay actually measured in advance.

After that, if the crank angle EFICA received from the EFI-ECU 32 has changed from the previously received crank angle EFICA, the MG-ECU 33 learns the crank angle.

That is, the estimated communication delay Tdest is added to the difference Txb-Tp between the pulse interrupt time Tp and the transmission buffer update time Ttxb to obtain the estimated time Tdelay that has elapsed since the pulse edge of the crank pulse signal from the crank angle sensor 34 was input to the EFI-ECU 32.

Then, the resolver angle RESATD before the elapsed time estimate Tdelay is obtained from the resolver angle RESA stored in the memory. If the elapsed time estimate Tdelay is not an integer multiple of the detection period of the resolver angle RESA, the resolver angle RESA obtained before and after the time point before the elapsed time estimate Tdelay may be obtained, and the resolver angle RESATD may be obtained by interpolation using those resolver angles RESA, or the resolver angle RESATD may be obtained by multiplying the difference between the elapsed time estimate Tdelay and any of the resolver angles obtained before and after the time point before the elapsed time estimate Tdelay by the motor rotational angular velocity of the generator motor 12. If the latter is adopted, the motor rotational angular velocity is stored in the memory in a state in which the time at which the motor rotational angular velocity was obtained can be specified, and the motor rotational angular velocity before the elapsed time estimate Tdelay is preferably used to calculate the resolver angle RESATD.

As in the case of the resolver angle RESATD, the damper torsion angle estimate DATD before the elapsed time estimate Tdelay is obtained from the damper torsion angle estimate DA stored in memory. The damper torsion angle estimate DATD is then added to the crank angle EFICA, and the resolver angle RESATD is subtracted from this sum to calculate the crank angle learning value THETADIF (step S207).

Then, the crank angle learning value THETADIF is added to the current resolver angle RESA, and the current damper torsion angle estimate DA is subtracted from the sum to calculate the current crank angle estimate CAEST (step S208). Once the crank angle learning value THETADIF has been obtained, the current crank angle estimate CAEST can be constantly calculated using the crank angle learning value THETADIF.

<Action and effect>
As described above, the MG-ECU 33 learns the relationship between the crank angle EFICA and the resolver angle RESATD before the elapsed time estimate value Tdelay, that is, the relationship between the crank angle EFICA and the resolver angle RESATD at the pulse interrupt time Tp, and estimates the current crank angle estimate value CAEST based on the relationship and the resolver angle RESATD. This allows the MG-ECU 33 to accurately estimate the crank angle of the engine 11 with high resolution, without increasing costs due to the provision of a dedicated communication line for communication between the MG-ECU 33 and the EFI-ECU 32.

As a result, the accuracy of the control that compensates for the torque fluctuation of the engine 11 with the compensation torque can be improved, and the gear rattle can be effectively reduced. As a result, when a crankshaft damper 19 for damping the vibration of the crankshaft 16 of the engine 11 is provided, the set torque of the crankshaft damper 19 can be reduced, and the occurrence of problems due to energy loss and heat generation by the crankshaft damper 19 can be suppressed. Furthermore, by reducing the set torque of the crankshaft damper 19, the torque variation and change over time of the crankshaft damper 19 are reduced, and the vibration of the crankshaft 16 is well damped. In addition, the engine 11 can be fired at a low rotation speed, and the power generation response of the generator motor 12 during rapid acceleration is improved, thereby improving the acceleration response of the vehicle.

The MG-ECU 33 calculates an estimated communication delay Tdest between the EFI-ECU 32 and the MG-ECU 33 from the time difference Tdif between the current time Tnow and the transmission buffer update time Ttxb, and uses the estimated communication delay Tdest to find an estimated time Tdelay that has elapsed from the pulse interrupt time Tp to the present. Then, the relationship between the resolver angle RESATD the elapsed time estimate Tdelay from the present and the crank angle EFICA at the pulse interrupt time Tp is learned.

This makes it possible to compensate for communication delays between the EFI-ECU 32 and the MG-ECU 33, and to estimate the crank angle of the engine 11 more accurately.

When learning the relationship between the crank angle EFICA and the resolver angle RESATD, the communication delay between the EFI-ECU 32 and the MG-ECU 33 is learned. Specifically, the time difference Tdif between the current time Tnow and the transmission buffer update time Ttxb is calculated. Then, if the time difference Tdif is greater than the currently held maximum retained value Tmax, the maximum retained value Tmax is updated with the time difference Tdif. Also, if the time difference Tdif is less than the currently held minimum retained value Tmin, the minimum retained value Tmin is updated with the time difference Tdif. Then, the average value Tcenter of the maximum retained value Tmax and the minimum retained value Tmin is calculated, and the expected value Text is added to the difference between the time difference Tdif and the average value Tcenter to estimate the communication delay estimated value Tdest.

This makes it possible to learn the steady-state communication delay time while eliminating the effects of variations in the actual communication delay. As a result, the relationship between the crank angle EFICA and the resolver angle RESATD at the pulse interrupt time Tp can be learned well, and the current crank angle can be accurately estimated as the crank angle estimated value CAEST based on the learned relationship.

<Modification>
Although the embodiment of the present invention has been described above, the present invention can be embodied in other forms.

For example, as shown in equation (3), the calculation of the damper torsional angle estimate DATD includes the second derivative of the motor rotation angle θmg of the generator motor 12, and therefore there is a delay Tdafilt due to the filter calculation for the second derivative. Therefore, in place of the damper torsional angle estimate DATD before the elapsed time estimate Tdelay, the calculation of the crank angle learning value THETADIF may use the damper torsional angle estimate DATD before the value (Tdelay-Tdafilt) obtained by subtracting the delay Tdafilt due to the filter calculation from the elapsed time estimate Tdelay. This makes it possible to obtain a more accurate crank angle learning value THETADIF, and the current crank angle can be estimated more accurately using the crank angle learning value THETADIF.

In addition, in the above embodiment, the case was described where the pulse interrupt time Tp and the transmission buffer update time Ttxb were transmitted from the EFI-ECU 32 to the MG-ECU 33, but if it is desired to reduce the amount of communication, only one of the pulse interrupt time Tp and the transmission buffer update time Ttxb may be transmitted.

For example, in a configuration in which the EFI-ECU 32 transmits the pulse interrupt time Tp to the MG-ECU 33 but does not transmit the transmission buffer update time Ttxb, the communication delay may be defined as the time from when the pulse interrupt time Tp is acquired in step S101 until the MG-ECU 33 receives the pulse interrupt time Tp and acquires the current time Tnow in step S204. In other words, the time difference Tdif may be set to a value obtained by subtracting the pulse interrupt time Tp from the current time Tnow. In this case, the communication delay estimate Tdest calculated in step S205 includes the time from when the pulse edge of the crank pulse signal is input to the EFI-ECU 32 to when the transmission buffer is updated, so in step S206, the communication delay estimate Tdest is used as the elapsed time estimate Tdelay.

However, since the elapsed time estimate Tdelay includes variability in the time from when the pulse edge of the crank pulse signal is input to the EFI-ECU 32 to when the transmission buffer is updated, the accuracy of learning the communication delay deteriorates; however, if the engine speed at which learning is performed is limited to a certain RPM or higher, the time from when the pulse edge of the crank pulse signal is input to the EFI-ECU 32 to when the transmission buffer is updated falls within a certain range, and the deterioration of the learning accuracy can be minimized.

In a configuration in which the EFI-ECU 32 transmits the transmission buffer update time Ttxb to the MG-ECU 33 but does not transmit the pulse interrupt time Tp, the transmission buffer update time Ttxb may be set as the time when the pulse edge of the crank pulse signal is input to the EFI-ECU 32, and in step S206, the communication delay estimate Tdest may be used as the elapsed time estimate Tdelay as is, or the expected value of the transmission buffer update time (corresponding to 1/2 the pulse interval) may be further added from the pulse edge input time according to the engine speed.

In addition, various design modifications can be made to the above-mentioned configuration within the scope of the matters described in the claims.

1: Hybrid vehicle (vehicle)
11: Engine 12: Generator motor 16: Crankshaft 17: Motor shaft (rotating shaft)
18: Meshing mechanism 32: EFI-ECU (engine control unit)
33: MG-ECU (motor control unit)
34: Crank angle sensor 35: Resolver

Claims (2)

A system for controlling the engine and the generator motor, the system being mounted on a vehicle having a meshing mechanism for transmitting power by meshing of teeth between a crankshaft of an engine and a rotating shaft of a generator motor, a crank angle sensor for outputting a crank pulse signal synchronized with rotation of the crankshaft, and a resolver for outputting a resolver signal that changes according to a rotation angle of the rotating shaft, the system comprising:
an engine control device that calculates a crank angle of the engine from the crank pulse signal and controls the engine using the calculated crank angle;
a motor control device that calculates a resolver angle from the resolver signal and controls the generator motor using the calculated rotation angle,
the engine control device and the motor control device are communicatively connected via an in-vehicle network established in the vehicle,
The engine control device includes:
a transmission buffer for temporarily storing the crank angle when transmitting the crank angle to the motor control device;
The motor control device includes:
receiving the crank angle calculated by the engine control device from the engine control device;
receiving from the engine control device a pulse interrupt time at which a pulse edge of the crank pulse signal is input to the engine control device and a transmission buffer update time at which the engine control device updates the transmission buffer;
estimating a communication delay time due to communication between the engine control device and the motor control device from a time difference between a current time and the transmission buffer update time;
Using the estimated communication delay time, an elapsed time from the pulse interrupt time to a current time is calculated;
The resolver angle before the elapsed time from the current time is acquired as the resolver angle at the pulse interrupt time, and a relationship between the crank angle and the resolver angle at the pulse interrupt time is learned;
The hybrid control system estimates the crank angle at the current time based on the learned relationship and the resolver angle. The motor control device includes:
2. The hybrid control system according to claim 1, further comprising: a time difference between a current time and the transmission buffer update time; if the calculated time difference is greater than a retained maximum value that is a currently held maximum value, the retained maximum value is updated with the time difference; if the calculated time difference is smaller than a retained minimum value that is a currently held minimum value, the retained minimum value is updated with the time difference; and an average value of the retained maximum value and the retained minimum value is subtracted from the time difference; and a preset expected value of the average value is added to the subtracted value to obtain a value that is an estimate of the communication delay time.

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