JP6852565B2 - Hybrid vehicle crank angle estimation method, crank angle control method and crank angle estimation device - Google Patents

Description

The present invention relates to a crank angle estimation method, a crank angle control method, and a crank angle estimation device for a hybrid vehicle.

Conventionally, in a hybrid vehicle powered by an engine and a motor, the crank angle is estimated using the detection value of the motor angle sensor and the detection value of the crank angle sensor (see, for example, Patent Document 1).

Japanese Patent No. 3770235

However, in the above-mentioned conventional crank angle estimation method, there is a problem that the estimation accuracy of the crank angle is low because the estimation accuracy of the crank angle depends on the detection variation of the crank angle sensor.
One of an object of the present invention is to provide a crank angle estimation method, a crank angle control method, and a crank angle estimation device for a hybrid vehicle capable of improving the crank angle estimation accuracy.

In the method for estimating the crank angle of a hybrid vehicle according to an embodiment of the present invention, the motor rotation angle when the motor is driven to rotate the engine in the reverse direction is detected or estimated, and the disturbance torque acting on the motor is estimated. Then, the estimated crank angle is calculated from the motor rotation angle based on the relationship between the motor rotation speed when the sign of the gradient of the disturbance torque is reversed and the crank angle when the intake valve of the predetermined cylinder of the engine is opened.

Therefore, in the method for estimating the crank angle of the hybrid vehicle of the present invention, the accuracy of estimating the crank angle can be improved.

It is a schematic block diagram of the power train in the hybrid vehicle of Embodiment 1. It is a schematic block diagram of the control system of the power train of Embodiment 1. FIG. It is a schematic block diagram of the motor controller 12 of Embodiment 1. It is a block diagram which shows the crank angle estimation control of Embodiment 1. FIG. It is a relationship diagram between the crank angle of the engine 1 and the opening / closing timing of the intake / exhaust valve. It is a relationship diagram between the combustion stroke of the engine 1 and the opening / closing timing of the intake / exhaust valve. It is a relationship diagram of the crank angle of the engine 1 and the engine compression reaction force. It is a compression reaction force characteristic diagram generated for each cylinder of engine 1. It is a compression reaction force characteristic diagram when the initial position is an arbitrary position which is not the compression top dead center. It is a relationship diagram between the initial crank angle (ATDC conversion) and the maximum compression reaction force ratio. It is a flowchart which shows the specific process flow of the crank angle estimation control and vibration suppression optimum crank angle control of Embodiment 1. It is a time chart which shows the crank angle estimation operation of Embodiment 1.

[Embodiment 1]
FIG. 1 is a schematic configuration diagram of a power train in the hybrid vehicle of the first embodiment.
In the hybrid vehicle of the first embodiment, the automatic transmission 3 is arranged in tandem on the rear side of the engine (power source) 1 in the vehicle front-rear direction, and the rotation of the engine 1 from the crank shaft 1a is rotated by the transmission input shaft of the automatic transmission 3. A motor generator 5 (hereinafter referred to as a motor) is provided by connecting to a motor torque shaft 4 transmitted to 3a. The engine 1 is a 6-cylinder, 4-stroke reciprocating gasoline engine in which the opening / closing timing of the intake / exhaust valves is linked to the rotational movement of the crank angle. The motor 5 is located between the engine 1 and the automatic transmission 3 and outputs torque to the motor torque shaft 4. The motor 5 functions as an electric motor or a generator depending on the operating state. A first clutch 6 is interposed between the crankshaft 1a and the motor torque shaft 4, and the engine 1 and the motor 5 are detachably coupled by the first clutch 6. The first clutch 6 has a transmission torque (clutch engagement) capacity that can be continuously changed. For example, the transmission torque (clutch engagement) capacity is continuously controlled by a proportional solenoid to continuously control the clutch hydraulic oil flow rate and the clutch operating hydraulic pressure. Is a wet multi-plate clutch that can be changed.

The motor 5 and the automatic transmission 3 are directly connected to each other by the coupling of the motor torque shaft 4 and the transmission input shaft 3a. The automatic transmission 3 is a stepped type, and shifts the rotation from the transmission input shaft 3a at a gear ratio according to the selected gear ratio and outputs the rotation to the transmission output shaft 3b. The rotation of the transmission output shaft 3b is distributed and transmitted to the left and right rear wheels (drive wheels) 2 and 2 by the differential gear device 8, and is used for traveling of the vehicle. In the first embodiment, as the second clutch 7 that detachably engages the motor 5 and the rear wheels 2 and 2, a shift friction element for forward gear selection or a shift for reverse gear selection existing in the automatic transmission 3 The friction element is diverted. Similar to the first clutch 6, the second clutch 7 can continuously change the transmission torque capacity.

In the power train shown in FIG. 1, when the electric vehicle (EV) mode used at low load and low vehicle speed including when starting from a stopped state is required, the first clutch 6 is released and the second clutch 7 is released. To put the automatic transmission 3 into the power transmission state. By driving the motor 5 in this state, the vehicle runs only with the output of the motor 5 (EV running). On the other hand, when the hybrid driving (HEV driving) mode used at high speed driving or heavy load driving is required, the first clutch 6 and the second clutch 7 are engaged together, and the automatic transmission 3 is put into a power transmission state. To do. By driving the engine 1 and the motor 5 in this state, the vehicle runs by the output of both the engine 1 and the motor 5 (HEV running). In the HEV driving mode, when the engine 1 is operated with the optimum fuel consumption and the energy becomes surplus, the surplus energy is converted into electric power by operating the motor 5 as a generator by the surplus energy, and this generated electric power is converted into electric power. The energy consumption of the engine 1 can be improved by storing electricity for use in driving the motor.

FIG. 2 is a schematic configuration diagram of the power train control system of the first embodiment.
The vehicle control controller 10 calculates the target drive torque of the vehicle based on the engine speed, the motor rotation, and the vehicle information (accelerator opening, vehicle speed, gear position, power generation request, first clutch engagement state, etc.), and the target drive torque. Is distributed to the target engine torque and the target motor torque and output to each of the controllers 11 and 12. The engine controller 11 calculates an engine torque command that realizes the target engine torque and drives the engine 1. The engine controller 11 calculates the engine speed from the crank angle detected by the crank angle sensor 13. The motor controller 12 calculates a motor torque command value that realizes the target motor torque, and drives the motor 5. The motor controller 12 calculates the motor rotation speed from the motor rotation angle detected by the resolver 14.

FIG. 3 is a schematic configuration diagram of the motor controller 12 of the first embodiment.
The motor controller 12 inputs the target motor torque and the motor rotation speed from the vehicle control controller 10, and outputs the motor rotation speed to the vehicle control controller 10. The motor controller 12 includes a rotation speed calculation unit 15, a motor torque control unit 16, a motor current control unit 17, and a crank angle estimation unit 18. The rotation speed calculation unit 15 calculates the motor rotation speed from the output of the resolver 14. The motor torque control unit 16 calculates a motor torque command value from a target motor torque, a motor rotation angle, a motor rotation speed, and a crank angle estimated value described later, and outputs the motor torque command value to the motor current control unit 17. The motor current control unit 17 determines the motor drive current according to the motor torque command value and outputs the motor drive current to the inverter 19. The inverter 19 supplies a three-phase current to the motor 5 according to the motor drive current. The crank angle estimation unit 18 calculates a crank angle estimated value from the motor rotation angle and a disturbance torque estimated value (compression reaction force estimated value) described later, and outputs the crank angle estimated value to the motor torque control unit 16.

The motor controller 12 disengages the first clutch 6 when the engine 1 is stopped in the stopped state in order to suppress floor vibration generated when the engine is started from the stopped state, such as when the engine is restarted after an idle stop. After engaging, the second clutch 7 is released, and the motor 5 is angle-controlled (rotation speed control) so that the crank angle becomes a predetermined vibration suppression optimum crank angle based on the crank angle estimated value calculated by the crank angle estimation unit 18. ) Perform optimal crank angle control. The optimum vibration suppression crank angle is an initial crank angle capable of suppressing the amplitude level of floor vibration generated when the engine speed passes through the resonance zone to an allowable level, that is, an initial crank angle effective for vibration suppression. Since there is a correlation between the initial crank angle and the amplitude level of floor vibration, the optimum crank angle for vibration suppression can be obtained in advance by experiments or simulations.

In the above optimum crank angle control, it is important to improve the estimation accuracy of the crank angle, but in the conventional crank angle estimation method, the estimation accuracy of the crank angle depends on the detection variation of the crank angle sensor, so that the estimation accuracy deteriorates. There is a scene to do. Therefore, in the first embodiment, with the aim of improving the estimation accuracy of the crank angle, the crank angle estimation unit 18 executes the crank angle estimation control as shown below prior to the above-mentioned optimum crank angle control.
FIG. 4 is a block diagram showing the crank angle estimation control of the first embodiment.
First, a negative rotation angle command value θm * is set as the rotation angle command value of the motor 5 required for crank angle estimation in order to rotate the engine 1 in the reverse direction. The "reverse direction" is the direction opposite to the rotation direction (forward rotation direction), which is the combustion stroke of the engine 1. The “rotating” is a state in which the crankshaft 1a is rotated by the motor 5 with the fuel injection and ignition to the engine 1 stopped.

In addition, the mating point 20 creates a difference between θm * and the motor rotation angle θm.
The gain block 21 multiplies the output of the addition point 20 by a predetermined gain a to generate a motor rotation speed command value ωm *.
In addition, the mating point 22 produces a difference between ωm * and the motor rotation speed ωm.
The multiplier 23 multiplies the output of the addition point 22 by a predetermined gain b to generate a motor torque command value Tm *.
The addition point 24 generates the final motor torque command value Tfin *, which is the difference between Tm * and the disturbance torque estimated value Trbst described later.
The actual plant block 25 substitutely represents the actual plant as the control target (motor 5). The actual plant block 25 multiplies Tfin * by the transfer function Gp'(s) to generate ωm. By outputting Tfin * to the actual plant, the angle of the motor 5 can be controlled so that it follows and converges on θm *.

The integration block 26 integrates ωm to generate a motor rotation angle θm.
The filter block 27 has a function as a low-pass filter, and multiplies Tfin * by the transfer function H (s) to generate a reference motor torque Tref.
The filter block 28 functions as a filter and multiplies ωm by the transfer function H (s) / Gp (s) to generate the motor applied torque estimate Tact. Gp (s) is a model of the transfer function between the torque input to the controlled object and the motor rotation speed. That is, the transfer function H (s) / Gp (s) is the inverse model 1 / Gp (s) of the transfer function H (s) and the transfer function Gp (s) between the torque input to the controlled object and the motor rotation speed. Is the product of. H (s) / Gp (s) is a proper transfer function. That is, in the fractional function representing H (s) / Gp (s), the numerator order is lower than the denominator order. The filter blocks 27 and 28 are disturbance torque estimation units.
In addition, point 29 generates Trbst, which is the difference between Tact and Tref. Trbst is input to the crank angle estimation unit 18 as the compression reaction force estimation value Tc.
The crank angle estimation unit 18 inputs θm and Tc, and calculates the crank angle estimation value θc based on the relationship between the intake / exhaust valve opening / closing timing and the crank angle, which is obtained in advance by a desk study using engine specifications.

Hereinafter, the crank angle estimation control of the first embodiment will be described in detail.
FIG. 5 is a diagram showing the relationship between the crank angle of the engine 1 and the opening / closing timing of the intake / exhaust valves.
In an engine such as engine 1 in which the opening / closing timing of the intake / exhaust valve is linked to the rotational movement of the crank angle, as shown in FIG. 5, the valve opening section and opening / closing timing of the intake valve and the exhaust valve are the cam shape and the crank angle. It is decided uniformly according to.
In the first embodiment, the intake valve closing timing in the compression stroke (crank angle from the compression top dead center TDC: θint) and the exhaust valve opening timing in the exhaust stroke (crank angle from the compression top dead center TDC: θext) are set. Focusing on this, in the engine 1 having the relationship of the following equation (1), the engine 1 is rotated in the reverse direction.
θint <θext… (1)

FIG. 6 is a diagram showing the relationship between the combustion stroke of the engine 1 and the opening / closing timing of the intake / exhaust valves.
In a 4-stroke engine such as engine 1, the combustion cycle is one cycle at a crank angle of 720 °, and the combustion cycle proceeds in the order of intake → compression → expansion → exhaust. FIG. 6 shows a combustion cycle in a certain cylinder and an open / closed state of an intake / exhaust valve during its rotational movement. The section where the motor 5 directly connected to the engine 1 receives the reaction force is the section where a differential pressure based on the atmospheric pressure is generated inside the cylinder during rotational motion, that is, the section where both the intake and exhaust valves are closed (all valves). Closed section) only. In FIG. 6, the closed section of the intake / exhaust valve is shown by a solid line, and the overlapping section corresponds to this. Expressed using the crank angle θint, which is the intake valve closing timing, and the crank angle θext, which is the exhaust valve valve opening timing, the valve fully closed section is (θint + θext).

FIG. 7 is a diagram showing the relationship between the crank angle of the engine 1 and the compression reaction force of the engine.
In FIG. 7, the vertical axis represents the reaction force [N · m] acting on the motor 5, and the horizontal axis represents the crank angle [deg]. The waveform is a waveform obtained by adding up the reaction forces of each cylinder generated when the engine 1 (6-cylinder engine) is rotated by the motor 5 with the first clutch 6 engaged. At this time, the initial angle before the start of the rotary motion was set to the angle at which any cylinder is located at the compression top dead center TDC. On the vertical axis, the torque acting in the direction opposite to the rotation direction of the motor 5 is the reaction force (positive value), and if the clockwise rotation is the forward rotation direction with respect to the vehicle traveling direction, the reaction force is on the left. It is the torque of rotation, and the reaction force in the reverse direction (counterclockwise rotation) is the torque of clockwise rotation.

Normally, when the engine 1 is rotated in the forward rotation direction, a change in the in-cylinder pressure that occurs in the fully closed section of the valve represented by (θint + θext) acts on the motor 5 as a reaction torque. This reaction force torque waveform has periodicity, and the period is the compression reaction force period θcyc calculated from one combustion stroke cycle and the number of cylinders. Further, from various engine specifications, the maximum peak value of the waveform is generated at a predetermined crank angle (compression reaction force maximum crank angle θmax) before the compression top dead center TDC.
On the other hand, when the engine 1 is rotated in the reverse direction, it has periodicity obtained from the compression reaction force period θcyc and the maximum compression reaction force crank angle θmax as in the forward rotation direction, but before reaching the first maximum peak. There is a scene in which the reaction force is largely released (compression reaction force is released). In the crank angle estimation control of the first embodiment, the estimation accuracy of the crank angle is improved by detecting the sign reversal of the gradient of the reaction force torque waveform.

FIG. 8 is a compression reaction force characteristic diagram generated for each cylinder of the engine 1.
In FIG. 8, with respect to the reaction force torque to the motor 5 shown in FIG. 7, only the cylinders that actually generate the reaction force (existing in the valve fully closed section) are extracted and applied to the motor 5 for each cylinder. The reaction force torque is drawn. In the case of a 6-cylinder engine, there are a total of three cylinders that generate reaction forces in the section rotated by about θcyc in the forward and reverse directions from the initial position (compressed TDC) similar to FIG. These cylinders are cylinders # 1, # 2, and # 3, and the initial position at this time is the compression top dead center (TDC) of cylinder # 1.

When the engine 1 is rotated in the forward rotation direction, cylinders # 1 and cylinders # 2 give reaction forces. The reaction force due to the increase in the in-cylinder pressure in the compression stroke in cylinder # 2 is predominant, and in addition to this, it is affected by the reaction force due to the decrease in in-cylinder pressure (negative pressure) in the exhaust stroke in cylinder # 1. At this time, if the relationship shown in the following equation (2) using θext, θcyc, and θmax is established, the reaction force release due to the exhaust valve opening in cylinder # 1 is the reaction force increase region (positive) in cylinder # 2. Occurs in the gradient region).
θext <(θcyc−θmax)… (2)
However, when Eq. (2) is not established as shown in FIG. 8, that is, when θext> (θcyc−θmax), the reaction force peak in cylinder # 2 is exceeded, that is, the region where the gradient is negative. Since the reaction force loss (negative gradient) of cylinder # 1 occurs in the above, it is difficult to detect the compression reaction force loss because both gradients are negative.

On the other hand, when the engine 1 is rotated in the reverse direction, the cylinder # 1 and the cylinder # 3 give a reaction force, and the reaction force due to the increase in the in-cylinder pressure in the expansion stroke of the cylinder # 3 is mainly dominated. In addition to this, it is affected by the reaction force due to the decrease in in-cylinder pressure (negative pressure) in the compression stroke in cylinder # 1. It should be noted that the notation of the combustion stroke in the reverse direction is adjusted to the forward direction for convenience, and is different from the actual physical phenomenon.
In the reverse direction, when the relationship shown in the following equation (3) using θint, θcyc, and θmax is established, the intake valve is opened in cylinder # 1 (although the valve is closed in the normal forward direction). , The valve opens in the reverse direction), and the reaction force is released in the reaction force rising region (positive gradient) in cylinder # 3.
θint <(θcyc−θmax)… (3)

In FIG. 8, since the engine specifications satisfy the equation (3), the gradient becomes negative before reaching the reaction force peak in the cylinder # 3, that is, in the region where the gradient is positive due to the reaction force loss of the cylinder # 1. Therefore, the loss of compression reaction force can be easily detected by detecting the sign reversal of the gradient.
In this way, the sign reversal of the slope of the motor reaction force occurs uniformly at the crank angle θint, which is the timing when the intake valve is closed. Therefore, the crank angle when this reversal phenomenon (compression reaction force loss) is detected is set to θint. Therefore, highly accurate crank angle estimation can be realized.
In the first embodiment, an engine having the relationship shown in the equation (1) is premised, and since the right side of the equation (2) and the equation (3) are the same, the more feasible equation (3) is used. Rotate the engine 1 in the reverse direction to estimate the crank angle.

FIG. 9 is a compression reaction force characteristic diagram when the initial position is an arbitrary position other than the compression top dead center.
In the same engine specifications as in FIG. 8, the cylinders that give reaction force to the motor 5 when the engine 1 is idled from the stopped state are extracted as cylinder # 1, cylinder # 2, and cylinder # 3, respectively, and their total reaction force is extracted. The torque is shown at the top. However, in FIG. 9, the initial position is a position rotated by θinit from the compression top dead center of cylinder # 1.
In the case of FIG. 9, as in FIG. 8, a reaction force is generated by cylinders # 1 and cylinders # 2 in the forward rotation direction. In this case, in addition to the equation (2), the sign reversal of the reaction force torque gradient can be detected only when the relationship shown in the following equation (4) considering the initial position θinit is established.
(θext−θinit) ＜ (θcyc−θmax−θinit)… (4)
Similarly, in the reverse direction, when the relationship of the following equation (5) considering θinit in addition to the equation (3) is established, the sign reversal of the reaction force torque gradient can be detected.
(θint ＋ θinit) ＜ (θcyc−θmax ＋ θinit)… (5)
In this way, even if the initial position is an arbitrary position, in the engine 1 having the specifications of Eq. (1), by rotating the engine 1 in the reverse direction, the sign reversal of the reaction force torque gradient can be performed. The detectable equation (5) is established, and the crank angle can be estimated accurately.

FIG. 10 is a diagram showing the relationship between the initial crank angle (ATDC conversion) and the maximum compression reaction force ratio.
In FIG. 10, the vertical axis represents the maximum compression reaction force ratio [-], and the horizontal axis represents the initial crank angle θinit (ATDC conversion). The horizontal axis shows the maximum compression reaction force ratio for each step value in the compression reaction force cycle θcyc with the compression top dead center of any cylinder as a reference (zero point). The maximum compression reaction force ratio on the vertical axis indicates the ratio of the force acting on the motor torque shaft 4 at the pressure generated by the compression / expansion of the air inside the cylinder while the engine is rotating. There is. The force acting on the motor torque shaft 4 is calculated by calculating the force acting on the motor torque shaft 4 based on the engine specifications such as cylinder surface area, valve opening / closing timing, and the amount of rotation in each cylinder, and the force generated in all cylinders. Is the sum of. In addition, in order to see the effect on the vibration immediately after the engine 1 is started, the amount of rotation from the start of rotation is set to one cycle of θcyc. At this time, the maximum value of the compression reaction force generated in each θinit is plotted with the normalized value based on the value of ATDC 0 °.

As is clear from FIG. 10, there is a difference in the maximum compression reaction force ratio when rotating to θcyc after starting the engine according to θinit, and the compression reaction force is the exciting force of vibration generated immediately after starting the engine. Assuming that, it can be seen that there is an optimum vibration suppression crank angle θideal, which is an initial crank angle effective for vibration suppression.
In the first embodiment, after the crank angle is estimated quickly and accurately by the crank angle estimation control, the floor vibration at the time of restarting the engine is suppressed by controlling the crank angle to θideal by the optimum crank angle control, and the occupant. To reduce the discomfort given to the engine.

FIG. 11 is a flowchart showing a specific processing flow of the crank angle estimation control and the optimum crank angle control of the first embodiment. This process is executed, for example, during idle stop.
In step S1, it is detected that the vehicle is stopped (vehicle speed 0 km / h) and engine 1 is stopped (engine speed 0 rpm).
In step S2, the first clutch 6 is engaged to maintain the stopped state, and the second clutch 7 is released to maintain the stopped state even during control.
In step S3, as the rotation angle command value θm * of the motor 1 required for estimating the crank angle, the rotation angle at which the sign reversal of the gradient of the compression reaction force waveform acting on the motor 5 is surely generated is set. θm * is set to a negative value in order to rotate the engine 1 in the reverse direction, and is set to, for example, a value for two cycles of the compression reaction force cycle θcyc − (2 × θcyc). Note that θm * is provided with a rate of change limit of a certain level or higher in order to prevent vehicle vibration due to sudden rotation due to step input.

In step S4, the angle of the motor 5 is controlled so that the motor rotation angle θm follows θm *.
In step S5, the crank angle estimated value θc is stored, and the remainder angle obtained by dividing θm by θcyc is stored as the pre-correction crank angle estimated value θcon.
In step S6, it is determined whether or not the phenomenon that the sign of the compression reaction force estimated value Tc is inverted has occurred. If YES, proceed to step S7, and if NO, return to step S4.
In step S7, the deviation between the crank angle θint, which is the intake valve closing timing, and the previous value θcon_z of the pre-correction crank angle estimated value is stored in θoff. Now, since θint is a positive value and θcon_z is a negative value, the deviation is calculated by adding both. The initial value of θoff is 0.

In step S8, the value obtained by subtracting θoff from θcon is defined as θc.
In step S9, θm * is reset for optimum crank angle control. Specifically, the difference value (θcyc−θint) between θcyc and θint, which is the rotation angle required to reach top dead center, and the vibration suppression optimum crank angle θideal were subtracted from the previous value θm_z of the motor rotation angle. Let the value be a new θm *.
In step S10, the angle of the motor 5 is controlled so that θm follows the newly set θm *.
In step S11, it is determined whether or not θm has reached θm *, that is, whether or not the crank angle has reached θideal. If YES, this control is terminated, and if NO, the process returns to step S10.

FIG. 12 is a time chart showing the crank angle estimation action of the first embodiment.
At time t1, since the stopped state and the stopped state of the engine 1 are detected, the motor controller 12 starts the crank angle estimation control, and the crank angle estimation unit 18 starts the estimation of the crank angle. The rotation angle command value θm * is a value at which sign reversal occurs in the gradient of the compression reaction force acting on the motor 5 when the engine 1 is rotated in the reverse direction, for example, a negative value twice the compression reaction force period θcyc ( -2 × θcyc).
In the section from time t1 to t2, the sign of the gradient of the compression reaction force estimation value Tc does not change, so the crank angle estimation correction value θoff is not updated with the initial value 0 stored, and the crank angle estimation value θc is before correction. Continue to calculate the estimated crank angle θcon, that is, the remainder angle obtained by dividing the motor rotation angle θm by θcyc.

At time t2, since the sign reversal of the Tc gradient was detected, θint and the pre-correction crank angle estimated value were used using the crank angle θint, which is the valve closing timing of the intake valve, which was obtained in advance by a desk study using engine specifications. The deviation from the previous value θcon_z is stored in θoff. As a result, after time t2, a highly accurate θc in which the deviation between the θcon and the true value of the crank angle is corrected can be obtained. At time t2, θm * for optimum crank angle control is reset. Specifically, the difference value between θcyc and θint, which is the rotation angle required to reach top dead center, and vibration suppression with respect to the previous value θm_z of the motor rotation angle at the time when the sign reversal of the gradient is detected (time t2). The value is obtained by subtracting the optimum crank angle θideal.
At time t3, θm reaches θm *, that is, the crank angle reaches θideal, so the optimum crank angle control ends. As a result, when the engine is restarted, the engine 1 is cranked from the optimum crank angle θideal for suppressing vibration, so that the floor vibration when the engine is restarted can be suppressed and the discomfort given to the occupants can be reduced.

In the first embodiment, the disturbance torque estimated value Trbst when the engine 1 is rotated in the reverse direction by the motor 5 is regarded as the compression reaction force of the engine 1 acting on the motor 5, and the Trbst, the motor rotation angle θm, and the crank angle are relative to the Trbst, the motor rotation angle θm, and the crank angle. The estimated crank angle θc is calculated based on the engine compression reaction force characteristics. By considering Trbst as the compression reaction force, the motor rotation angle θm (actually, the remainder angle obtained by dividing θm by the compression reaction force cycle) when the compression reaction force loss occurs (the sign of the compression reaction force gradient is reversed) is Therefore, it is possible to associate the motor rotation angle θm with the crank angle. If the θm can be associated with the crank angle, the crank angle can be estimated from the sequentially detected θm.
In the crank angle estimation control of the first embodiment, the crank angle is detected by detecting the compression reaction force loss that occurs mechanically in conjunction with the crank angle, as compared with the conventional estimation method that depends on the detection variation of the crank angle sensor. The estimation accuracy can be improved. In general, a resolver that detects the rotation angle of a motor has a higher resolution than a crank angle sensor. Therefore, by estimating the crank angle from θm, the crank angle can be estimated accurately in the motor controller 12 that does not have the crank angle information. As a result, the control accuracy of the vibration suppression optimum crank angle control is improved, and the floor vibration at the time of restarting the engine can be reduced.

In the first embodiment, the following effects are obtained.
(1) This is a method for estimating the crank angle of a hybrid vehicle powered by the motor 5 and the engine 1. The engine 1 is connected to the motor 5 and the motor 5 is started with the fuel injection and ignition to the engine 1 stopped. When 1 is driven in the reverse direction, the motor rotation angle θm when the engine 1 is reverse is detected, the disturbance torque estimated value Trbst acting on the motor 1 is calculated, and the sign of the gradient of Trbst is reversed. Based on the relationship between θm of the above and the crank angle θint when the intake valve of cylinder # 1 of the engine 1 is opened, the estimated crank angle θc is calculated from the motor rotation angle θm.
Therefore, the estimation accuracy of the crank angle can be improved by detecting the sign reversal of the gradient of the compression reaction force generated mechanically in conjunction with the crank angle and associating the crank angle with θm. Further, by rotating the engine 1 in the reverse direction, it is possible to facilitate the detection of the loss of compression reaction force as compared with the case where the engine 1 is rotated in the forward direction. Further, since the compression reaction force is generated before the compression reaction force reaches the first maximum peak, the time required for estimating the crank angle can be shortened.

(2) The crank angle θint from the compression top dead center TDC corresponding to the valve opening timing of the intake valve of cylinder # 1 when the engine 1 is reversed is the crank angle (θcyc) from the TDC corresponding to the peak timing of the disturbance torque. Less than −θmax). That is, the engine 1 holds the relationship of Eq. (3).
Therefore, before the compression reaction force reaches the peak, that is, in the region where the gradient of the compression reaction force is positive, the compression reaction force is released due to the opening of the intake valve, so that the sign reversal of the compression reaction force can be surely generated.

(3) The crank angle θint from the compression top dead center TDC corresponding to the closing timing of the intake valve of cylinder # 1 when the engine 1 is reversed is the opening of the exhaust valve of cylinder # 1 when the engine 1 is rotating forward. It is smaller than the crank angle θext from the TDC corresponding to the timing. That is, the engine 1 holds the relationship of Eq. (1).
Therefore, the probability that the sign of the compression reaction force is reversed when the compression reaction force is released can be increased as compared with the case where the engine 1 is rotated in the normal direction.

(4) Calculate the pre-correction crank angle estimated value θcon from the motor rotation angle θm and the period of the compression reaction force of the engine 1, the crank angle θint when the intake valve of the cylinder # 1 of the engine 1 opens, and the gradient of the disturbance torque. The crank angle estimation correction value θoff is calculated from the deviation from the motor rotation angle when the sign of is reversed, and θcon is corrected by θoff to calculate the crank angle estimation value θc.
Therefore, the crank angle can be estimated with high accuracy.

(5) Using the formula model Gp'(s) of the motor 5 that inputs the final motor torque command value Tfin * and outputs the motor rotation speed ωm, the motor rotation speed ωm is the inverse system of the formula model 1 / Gp ( The disturbance torque estimate Trbst is estimated by subtracting the normative motor torque Tref obtained by multiplying Tfin * by H (s) from the motor applied torque estimate Tact multiplied by s) and the low-pass filter H (s).
Therefore, by using the inverse model of the controlled object (motor 5), the disturbance torque acting on the motor 5 can be estimated accurately.

(6) The engine 1, the first clutch 6, the motor generator 5, the second clutch 7, and the rear wheels 2 and 2 are arranged in the order of the transmission paths, and the motor controller 12 is in the engaged state of the first clutch 6 and the second. This is a crank angle control method for a hybrid vehicle in which the crank angle of the engine 1 is stopped at the optimum crank angle for suppressing vibration by the motor generator 5 when the clutch 7 is released. The crank angle estimated value θc calculated by the crank angle estimation unit 18 Based on the above, the crank angle is stopped at the optimum crank angle for suppressing vibration.
Therefore, it is possible to realize highly accurate optimum crank angle control and reduce floor vibration when the engine is restarted. Further, since the estimated crank angle time can be shortened, the crank angle can be set to the optimum crank angle for suppressing vibration at an early stage. As a result, the optimum crank angle control can be executed even when the time from the start of the idle stop to the restart of the engine is short.

(7) A crank angle estimation device for a hybrid vehicle powered by a motor 5 and an engine 1. The first clutch 6 that connects the engine 1 and the motor 5 and the engine 1 and the motor 5 are connected to each other to form an engine. The motor controller 12 that drives the motor 5 in the direction in which the engine 1 reverses with the fuel injection and ignition of the motor 1 stopped, the resolver 14 that detects the rotation angle θm of the motor 1, and the disturbance torque estimated value Trbst of the motor 5. Based on the relationship between the disturbance torque estimation unit (filter blocks 27, 28) to be calculated, θm when the sign of the gradient of Trbst is inverted, and the crank angle θint when the intake valve of the predetermined cylinder # 1 of engine 1 opens. The crank angle estimation unit 18 for calculating the crank angle estimation value θc from the motor rotation angle θm is provided.
Therefore, the estimation accuracy of the crank angle can be improved by detecting the sign reversal of the gradient of the compression reaction force generated mechanically in conjunction with the crank angle and associating the crank angle with θm. Further, by rotating the engine 1 in the reverse direction, it is possible to facilitate the detection of the loss of compression reaction force as compared with the case where the engine 1 is rotated in the forward direction. Further, since the compression reaction force is generated before the compression reaction force reaches the first maximum peak, the time required for estimating the crank angle can be shortened.

(Other embodiments)
Although the embodiments for carrying out the present invention have been described above based on the embodiments, the specific configuration of the present invention is not limited to the embodiments, and the design changes within a range that does not deviate from the gist of the invention. Etc. are included in the present invention.
For example, the second clutch 7 may have a configuration in which the transmission torque capacity can be changed by continuously engaging and releasing a plurality of friction elements of the automatic transmission 3. Further, the automatic transmission 3 may be a continuously variable transmission.
In FIG. 4, the Tc (Trbst) output from the addition point 29 may be filtered by a notch filter to remove the frequency component of the torque ripple of the motor 5. Further, Tc may be filtered by a low-pass filter to remove high-frequency components. As a result, it is possible to reduce the estimated variation caused by torque ripple, measurement noise, and the like.

1 engine
2 Rear wheels (drive wheels)
5 motor generator
6 1st clutch
7 2nd clutch
12 Motor controller (motor control unit)
13 Crank angle sensor
14 Resolver (motor rotation angle detector)
18 Crank angle estimation unit
27 Filter block (disturbance torque estimation unit)
28 Filter block (disturbance torque estimation unit)

Claims (7)

A method for estimating the crank angle of a hybrid vehicle powered by a motor and engine.
The engine and the motor are connected, and the motor is driven in a direction in which the engine reverses while fuel injection and ignition to the engine are stopped.
The motor rotation angle when the engine is reversed is detected or estimated, and the disturbance torque acting on the motor is estimated.
A crank angle estimated value is calculated from the motor rotation angle based on the relationship between the motor rotation angle when the sign of the disturbance torque gradient is reversed and the crank angle when the intake valve of a predetermined cylinder of the engine opens. How to estimate the crank angle of a hybrid vehicle. In the method for estimating the crank angle of a hybrid vehicle according to claim 1,
When the engine is reversed, the crank angle from the compression top dead center corresponding to the valve opening timing of the intake valve is smaller than the crank angle from the compression top dead center corresponding to the peak timing of the disturbance torque. Crank angle estimation method. In the method for estimating the crank angle of a hybrid vehicle according to claim 2,
The crank angle from the compression top dead center corresponding to the valve closing timing of the intake valve at the time of reverse rotation of the engine is the crank angle from the compression top dead center corresponding to the valve opening timing of the exhaust valve at the time of normal rotation of the engine. Crank angle estimation method for smaller hybrid vehicles. In the method for estimating the crank angle of a hybrid vehicle according to any one of claims 1 to 3,
The pre-correction crank angle estimated value is calculated from the motor rotation angle and the compression reaction force cycle of the engine.
The crank angle estimation correction value is calculated from the deviation between the crank angle when the intake valve of the engine is opened and the motor rotation angle when the sign of the gradient of the disturbance torque is reversed.
A method for estimating a crank angle of a hybrid vehicle in which the estimated crank angle before correction is corrected by the estimated corrected crank angle and the estimated crank angle is calculated. In the method for estimating the crank angle of a hybrid vehicle according to any one of claims 1 to 4.
Using the mathematical model of the motor that inputs the motor torque command value and outputs the motor rotation speed, the value obtained by multiplying the motor rotation speed by the inverse system of the mathematical model and the low-pass filter is converted to the motor torque command value. A method for estimating a crank angle of a hybrid vehicle for estimating the disturbance torque by subtracting a value multiplied by the low-pass filter. The engine, the first clutch, the motor, the second clutch, and the drive wheels are arranged in the order of the transmission paths.
A method for controlling a crank angle of a hybrid vehicle in which a motor controller stops the crank angle of the engine to a predetermined optimum crank angle by the motor while the first clutch is engaged and the second clutch is released. ,
A crank angle control method for a hybrid vehicle that stops the crank angle of the engine at the optimum crank angle based on the crank angle estimated value calculated by using the crank angle estimation method according to any one of claims 1 to 5. A crank angle estimation device for hybrid vehicles powered by a motor and engine.
A clutch that connects the engine and the motor,
A motor control unit that connects the engine and the motor and drives the motor in a direction in which the engine reverses while fuel injection and ignition to the engine are stopped.
A motor rotation angle detection unit that detects the rotation angle of the motor,
A disturbance torque estimation unit that estimates the disturbance torque acting on the motor,
A crank angle estimated value is calculated from the motor rotation angle based on the relationship between the motor rotation angle when the sign of the gradient of the disturbance torque is reversed and the crank angle when the intake valve of the predetermined cylinder of the engine opens. Crank angle estimation unit and
Crank angle estimation device for hybrid vehicles equipped with.

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