JP2000238555A - Engine start control device, control method, and hybrid vehicle - Google Patents

Abstract

(57) [Problem] To provide a start control device for appropriately executing a complete explosion judgment of an engine at start. SOLUTION: Engine, motor MG1, motor MG2
And a hybrid vehicle in which the axles are connected via planetary gears. The engine is cranked and started by the torque of the motor MG1. If the engine speed is lower than the ignition speed Netag, the motor MG1
Is changed in a predetermined pattern. After the ignition speed has been reached and the operation of engine 150 has been started, the torque of MG1 is set by PI control so that the engine speed reaches a predetermined target speed N1 *. At this time, the target rotation speed N * is smaller than the rotation speed Ne * during the idle operation of the engine.
Set 1 * low. Engine idle speed Ne *
, The torque of the motor MG1 turns negative. Due to the torque fluctuation, the complete explosion determination can be appropriately performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a start control device and a control method for starting an engine by the power of an electric motor connected to the engine. Further, the present invention relates to a hybrid vehicle using an engine and an electric motor as power sources, and having the engine start control device mounted thereon.

[0002]

2. Description of the Related Art In recent years, hybrid vehicles having an engine and an electric motor as power sources have been proposed. Hybrid vehicles include a series hybrid vehicle and a parallel hybrid vehicle. A series hybrid vehicle refers to a hybrid vehicle in which the engine is only coupled to the generator and is not mechanically coupled to the drive shaft. In a series hybrid vehicle, power can be generated by driving a generator with the power of an engine. This power is used to charge the battery and is also supplied to a drive motor coupled to the drive shaft. The series hybrid vehicle runs on the power of the electric motor. The mechanical power from the engine cannot be transmitted directly to the drive shaft.

[0003] A parallel hybrid vehicle is a hybrid vehicle in which an engine and a drive shaft are mechanically connected. The engine is connected not only to the drive shaft but also to a generator. In a parallel hybrid vehicle, at least a part of the power output from the engine can be transmitted to the drive shaft. Further, power can also be generated by driving a generator coupled to the engine with the power of the engine. Further, the vehicle can be driven by powering an electric motor coupled to a drive shaft. By powering the electric motor, it is possible to supplement the power transmitted from the engine to the drive shaft and output the required power from the drive shaft to travel.

In the above-described hybrid vehicle, the operation of the engine is controlled according to the running state of the vehicle. For example,
In a series hybrid vehicle, the operation of the engine is stopped when the battery is charged with sufficient power for powering the electric motor. When the power of the battery is consumed and charging is required, the engine is started and charging is started. In a parallel hybrid vehicle, the engine is stopped when the vehicle starts moving, and the vehicle travels using the power of the electric motor. When the vehicle reaches a predetermined vehicle speed, the engine is started and the vehicle runs using the power of the engine. The point that the start / stop of the engine is controlled according to the state of charge of the battery is the same as in the series hybrid vehicle.

[0005] In a vehicle using only an engine as a power source, the engine is usually in an operating state while the vehicle is running. In a normal vehicle, a driver operates an ignition switch to start an engine when starting driving of the vehicle. When the driver turns on the ignition switch, the engine is cranked by the power of a so-called cell motor. When the rotational speed of the engine reaches about several hundred rpm, fuel injection and ignition are performed, and the operation of the engine is started. When the operation starts, the number of revolutions of the engine rapidly increases to about 1000 rpm. The driver recognizes that the self-sustained start of the engine has been started from the change in the rotation speed, and completes the operation for starting the engine.

[0006] On the other hand, in a hybrid vehicle, the engine is started and stopped during traveling regardless of the operation of the driver. In the hybrid vehicle, the start control device starts the engine in response to the engine start request. Upon receiving a request to start the engine, the start control device executes a cranking by powering an electric motor coupled to the engine. When the engine reaches a predetermined number of revolutions, fuel injection and ignition are performed to start the operation of the engine. When it is determined that the engine has started self-sustaining operation (hereinafter, referred to as complete explosion determination), the start control device ends the process for starting the engine.

[0007]

In a hybrid vehicle, the start and stop of the engine are repeatedly performed during traveling. Therefore, it is preferable to start the engine smoothly in order to ensure a sufficiently comfortable ride. In order to realize such a start, in a hybrid vehicle, fuel injection and ignition are performed after the rotation speed is increased to near the rotation speed during self-sustaining operation by cranking. For this reason, the fluctuation in the number of revolutions before and after the start of the self-sustaining operation is relatively small, and it is difficult to determine whether or not the engine has started the self-sustaining operation from the number of revolutions of the engine. In the conventional hybrid vehicle, the complete explosion of the engine is determined based on the engine speed and the elapsed time after ignition.

[0008] However, in such a method, there is a case where an appropriate complete explosion determination cannot be executed. For example, when the elapsed time after ignition is set short, there is a possibility that the operation of the electric motor is stopped even though the engine has not sufficiently started the self-sustaining operation. As a result, the engine may not be able to start the self-sustaining operation due to the frictional load of the power system and may stop. Conversely, when the elapsed time is set to be long, the electric motor is operated even though the engine has already started the self-sustaining operation, and the power consumption has increased.

In the case of a parallel hybrid vehicle,
If the above-described elapsed time is set to be long, the responsiveness of the running vehicle is impaired. This is because, during traveling, it is desired to immediately end the engine start control and shift to traveling using engine power. Further, the time until the engine starts the self-sustaining operation changes according to various operating conditions such as the engine water temperature. The conventional start control device cannot perform an appropriate complete explosion determination that meets all of these circumstances.

[0010] The above-mentioned problems are not limited to hybrid vehicles. This is a problem common to all start control devices that need to determine the self-sustaining operation of the engine. The present invention has been made to solve such a problem, and an object of the present invention is to provide a start control device and a control method capable of appropriately performing a complete explosion determination of an engine.
It is another object of the present invention to provide a hybrid vehicle to which the start control device is applied.

[0011]

Means for Solving the Problems and Their Functions / Effects In order to solve at least a part of the above problems, the present invention has the following constitution. A start control device according to the present invention is a start control device that rotates the engine by the power of an electric motor coupled to the engine, and supplies and ignites fuel to operate the engine independently. Power setting means for setting the required power at the time;
An engine control means for controlling the operation of the engine in an operation state corresponding to the required power; and a motor target rotation that is significantly lower than the engine speed realized by the engine control means within a range that does not hinder the operation of the engine. The gist of the present invention is to provide a motor control means for rotating the motor by a number, and a self-sustained operation determination means for determining whether or not the engine has started self-sustained operation based on the torque of the motor.

According to such a start control device, it is possible to appropriately determine whether the engine has completely exploded based on fluctuations appearing in the torque of the electric motor as a result of the interaction between the engine control means and the electric motor control means. That is, according to the starting device, after the self-sustaining operation of the engine is started, the engine control means operates the engine in an operating state corresponding to the required power. The control by the engine control means can take various forms. For example, control can be performed so that the product of the rotational speed and the torque, that is, the output power corresponds to the required power.
Further, control may be performed such that the engine is operated at a predetermined rotational speed determined according to the required power. In a state in which self-sustaining operation has not been started even though fuel has been supplied and ignited to the engine, the engine control means cannot naturally function effectively, and the engine is in an operating state corresponding to the required power. No.

On the other hand, in the starting control device of the present invention, the motor control means controls the rotation of the motor. Since the electric motor is connected to the engine, it controls the engine speed indirectly. That is, the electric motor control means controls the electric motor to rotate the engine at a rotational speed significantly lower than the rotational speed realized by the engine control means. After the engine starts self-sustaining operation and the engine control means starts to function effectively, a negative torque is output from the electric motor in order to reduce the rotation speed to the motor target rotation speed. Before the engine starts self-sustaining operation, that is, in a state where the engine control means is not functioning effectively, since the engine speed is lower than the motor target speed, a positive The torque is output.

As described above, according to the starting control device of the present invention, the operating state of the engine is controlled by the two means of the engine control means and the motor control means. As a result, the output torque of the electric motor varies depending on whether the engine control means functions effectively, that is, whether the engine has started self-sustaining operation. In the start control device of the present invention, it is determined whether or not the engine has started the self-sustaining operation based on the thus-obtained fluctuation of the electric motor torque. Fluctuations in the torque of the motor can be easily and accurately detected based on the torque command value by the motor control means. Therefore, according to the start control device of the present invention, the complete explosion determination can be appropriately performed.

Here, the terms used in this specification are defined. In this specification, “start” refers to a state from the stop of the engine to the start of independent operation. The self-sustaining operation means that the engine is in an operation state in which the engine can continue rotating without torque from the electric motor. When fuel injection and ignition of the engine are initially started, there is a case where the self-sustaining operation cannot be performed yet. In this specification, the term "start of operation" is used for such a condition.

As described above, the target motor speed is
It is a target engine speed used for setting the torque of the electric motor. Therefore, whether or not the motor target rotation speed is significantly lower than the engine target rotation speed is determined in a state immediately before the power output from the motor is transmitted to the engine. For example, when the motor is coupled to the engine via the transmission, the rotation speed immediately before transmission to the engine via the transmission is set as the motor target rotation speed. The present invention includes a case where the rotation speed of the motor itself is not significantly lower than the engine rotation speed, such as a case where the motor is coupled to the engine via the transmission.

Note that the range of the rotational speed which is significantly lower is a range in which the fluctuation of the torque of the electric motor can be detected based on the above control. If the motor target rotation speed is extremely lower than the engine rotation speed, the load applied by the motor after the engine starts the self-sustaining operation increases. The rotation of the engine may be hindered by this load, and the operation may be stopped. If the motor target rotation speed is lower than the rotation speed at which the engine is ignited, the rotation speed of the engine cannot be sufficiently increased and the operation cannot be started. The “range that does not hinder the operation of the engine” in the present invention means a range that does not hinder the start and continuation of the operation of the engine.

On the other hand, when the target motor speed is set to a value substantially equal to the engine speed, there is a possibility that the power output from the engine and the torque of the motor do not fluctuate. When controlling the operation of the engine based on the fluctuation of the rotational speed, it is usual to provide a predetermined dead zone in order to avoid frequent fluctuations in the operation state of the engine. It is desirable that the motor target rotation speed is set at least within a range outside the dead zone.

In the present invention, the engine speed as a reference for setting the motor target speed differs according to the manner of control of the engine by the engine control means. For example, when the engine is controlled to rotate at a predetermined rotation speed, the rotation speed may be set as the engine rotation speed.

On the other hand, consider the case where the engine is controlled so that the required power is output from the engine instead of controlling the rotation speed and the torque to predetermined values. In such a case, the number of revolutions realized by the engine control means varies according to the load applied to the engine. Normally, control is performed such that the engine is rotated at a desired rotational speed by applying a load by an electric motor.
Therefore, the engine speed realized by the engine control means means the speed realized when there is no load by the electric motor. If the rotation speed realized by the engine control means can vary due to factors other than the motor that loads the engine, it is desirable to set the motor target rotation speed in consideration of such a variation range.

As described above, in the present invention, the required power during the self-sustaining operation can be set to various values. Various methods can be applied to engine control. As described above, the present invention can be configured in various aspects. In particular, the power setting unit is a unit that sets the required power to a value of 0, and the engine control unit is configured to set the required power at a predetermined engine speed. Preferably, it is a means for rotating the engine.

In general, the higher the required power during the self-sustaining operation, the higher the engine speed and the higher the output torque. Generally, an engine is provided with a plurality of combustion units, and the start of operation often varies at the time of startup. In other words, even after some of the combustion units have reached the state in which the self-sustained operation can be started, the other combustion units may not be in the self-sustained operation. Such variations cause vibration at the time of starting. If the required power at the time of the self-sustaining operation is small, the power output at each combustion section is small, so that the influence of the variation is small. Therefore, as described above, if the required power is set to the value 0, the vibration at the time of starting can be sufficiently reduced.

Further, the fuel consumption at the time of starting varies depending on the required power. Usually, there is more harmful gas, that is, so-called emission at the time of startup than after the start of self-sustaining operation.
The amount of emissions varies according to the required power. Therefore, as described above, if the required power is set to the value 0, the fuel consumption and the emission at the time of starting can be suppressed.

On the other hand, the operating state according to the required power of the value 0 includes stopping the engine and operating in a so-called idle state. Needless to say, in order to properly start the engine, it is desirable for the engine control means to execute control for operating the engine with the number of revolutions in the idle state.

The operation when the present invention is configured in the above-described manner will be described in detail. After the operation of the engine is started, the engine control means operates the engine at a rotation speed corresponding to the idle rotation speed. On the other hand, the motor control means applies a load to the engine such that the engine speed decreases to the motor target speed. The engine control means increases the fuel injection amount or the like so as to maintain the idle speed while resisting this load. As a result, the electric motor continues to output negative torque, and the power output from the engine increases. Since the engine speed is controlled by the two control means having different target speeds, the torque of the electric motor becomes negative due to the interaction between the two after the engine starts self-sustaining operation. Therefore, if the start control device is configured in the above-described manner, the complete explosion of the engine can be appropriately determined.

In the case where the required power is set to a value of 0, a temperature detecting means for detecting the temperature of the engine is provided, and the power setting means sets the temperature to a predetermined value or less which is determined according to the ease of ignition of the engine. In this case, it is preferable that the request power is a means for setting the required power to a positive predetermined value.

Generally, an engine ignites vaporized fuel to obtain power. When the temperature of the engine is very low, it is normal for the fuel to hardly vaporize and ignite. According to the start control device, when the engine temperature is equal to or lower than the predetermined value, the required power is set to a positive value. If the required power increases, the fuel injection amount increases, so that combustion is promoted and starting is facilitated. Therefore, according to the above-described start control device, the engine can be appropriately started when the temperature is low. In this case, the required power may be a predetermined constant value or a value corresponding to the temperature of the engine.

The start control device of the present invention is applicable to various devices that need to execute the start of the engine. Of course, it is also possible to apply to various power output devices using only the engine as a power source. In such a case, there is an advantage that the engine can be appropriately started regardless of whether the start / stop of the engine is repeatedly performed during the operation of the power output device. In addition, there is an advantage that fuel consumption and emission at the time of starting are reduced.

As described above, the present invention is applicable to a power output device using only an engine as a power source, but is particularly applicable to a hybrid power output device using an engine and an electric motor as power sources. preferable. This is because the hybrid power output device repeatedly starts and stops the engine during operation. Among them, as shown below:
It is preferable to apply the start control device of the present invention and configure the invention as a hybrid vehicle.

The hybrid vehicle according to the present invention is equipped with an engine and a first electric motor as power sources, and runs while controlling start and stop of the engine by a second electric motor coupled to the engine. A vehicle that controls the second electric motor to rotate the engine in response to a request to start the engine, and supplies and ignites fuel to the engine; Power setting means for setting the required power during self-sustaining operation, engine control means for operating the engine in an operating state corresponding to the required power, and engine control means provided that the operation of the engine is not hindered. Motor control means for rotating the second motor at a motor target rotation speed significantly lower than the engine rotation speed, The engine is summarized in that and a self-sustained operation determining means for determining whether to start self-sustained operation on the basis of the torque of the electric motor.

According to such a hybrid vehicle, the engine can be appropriately started by the same operation as described in the start control device. Hybrid vehicles are
Since it is possible to travel only by the power source of the electric motor, the start and stop of the engine are repeatedly performed during traveling. According to the hybrid vehicle of the present invention, it is possible to appropriately start the engine that is repeatedly executed as described above, so that stable driving can be realized, and fuel efficiency can be improved and emission can be reduced. it can.

Note that the hybrid vehicle of the present invention may have any configuration of a series hybrid vehicle and a parallel hybrid vehicle. If the first motor and the second motor are different motors and a configuration in which the engine and the drive shaft are not coupled is applied, a series hybrid vehicle is obtained. Further, if the first motor and the second motor are different motors and the engine and the drive shaft are connected,
The result is a parallel hybrid vehicle equipped with two electric motors.
Furthermore, if the first electric motor and the second electric motor are a common electric motor, a parallel hybrid vehicle provided with one electric motor is obtained. The present invention may employ any configuration.

In the hybrid vehicle according to the present invention, as in the start control apparatus described above, the power setting means includes:
It is preferable that the required power is set to a value of 0, and the engine control means is a means for rotating the engine at a predetermined engine speed. By setting the required power in this manner, vibration, fuel consumption, and emission at the time of engine start can be suppressed, as described earlier with the start control device. In particular, suppression of vibration is preferable in that the riding comfort of the hybrid vehicle is greatly improved.

Further, when the required power is set to a value of 0, there is provided a temperature detecting means for detecting the temperature of the engine, and the power setting means has a predetermined temperature which is determined according to the easiness of ignition of the engine. In the case where the required power is equal to or less than the value, it is preferable that the request power is a means for setting the required power to a positive predetermined value. This makes it possible to appropriately start the engine at a low temperature.

When the required power is set to a value of 0, in addition,
The vehicle further comprises stop determination means for determining whether or not the vehicle is stopped, and the power setting means is means for setting the required power to a positive predetermined value when the vehicle is not stopped. It is also preferable to

According to such a hybrid vehicle, the required power is set to a value of 0 while the vehicle is stopped, and is set to a positive predetermined value while the vehicle is running. When the engine is started during running, it is usually required to run using the power of the engine. If the vehicle continues to travel under such a situation, battery power is consumed. Therefore, when starting of the engine is requested during traveling, it is desirable to output power from the engine promptly. According to the above hybrid vehicle, since the engine is started with the required power of the engine as a positive predetermined value, the power can be output quickly. Therefore, the power consumption of the battery can be suppressed, and the responsiveness of the vehicle can be improved.

The required power when starting during running is:
It may be a fixed value set in advance, or the running state of the vehicle,
For example, the value may be determined according to the vehicle speed, the amount of depression of the accelerator, and the like. In the latter case, the required power may be changed continuously or stepwise.

Further, the power required to make the required power positive at a low temperature may be applied in various modes. For example, the required power may be set to the value 0 only when the engine is at a temperature equal to or higher than a predetermined value and the vehicle is stopped, and may be set to a positive predetermined value in other cases. The required power may be set to a value of 0 when the vehicle is stopped or when the engine satisfies one of the predetermined temperatures or more, and may be set to a positive predetermined value in other cases. It is possible to apply in combination in various other aspects.

The present invention can be configured as an engine control method described below. That is, the control method of the present invention is a control method of rotating the engine by the power of an electric motor coupled to the engine, and supplying and igniting the fuel to operate the engine independently,
(A) a step of setting a required power of the engine during self-sustaining operation; (b) a step of operating the engine in an operating state corresponding to the required power; and (c) a range in which the operation of the engine is not hindered. Rotating the motor at a motor target speed significantly lower than the engine speed realized by the engine control means; and (d) determining whether the engine has started self-sustaining operation based on the torque of the motor. And a step of judging whether or not it is a control method.

According to this control method, the engine can be stably and appropriately started by the same operation as described above as the start control device. It goes without saying that the various additional elements described in the start control device can be applied to the control method. Further, the invention as the control method of the engine may be configured as the invention of the control method of the hybrid vehicle.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples. (1) Configuration of Embodiment: First, the configuration of a hybrid vehicle as an embodiment of the present invention will be described. FIG. 1 is an explanatory diagram showing a configuration of a power system that outputs power of the hybrid vehicle. The engine 150 provided in the power system is a normal gasoline engine, and has a crankshaft 156.
To rotate. The engine 150 of the present embodiment includes a mechanism (hereinafter, referred to as a VVT mechanism) that can adjust the opening and closing timing of the intake valve and the exhaust valve. Since the configuration of the VVT mechanism is well known, detailed description will be omitted.

The operation of the engine 150 and the VVT mechanism are controlled by the EFIECU 170. EFIEC
U170 is a one-chip microcomputer having a CPU, a ROM, a RAM, and the like therein.
In accordance with the program recorded in M, the fuel injection amount of the engine 150 and other controls are executed.

The power system includes other motors MG1 and MG2.
Is provided. Motors MG1 and MG2 are synchronous motors, and rotor 1 having a plurality of permanent magnets on the outer peripheral surface.
32, 142 and a three-phase coil 13 for forming a rotating magnetic field.
1 and 141 wound around the stators 133 and 143. Stators 133 and 143 are fixed to case 119. Stators 133, 1 of motors MG1, MG2
The three-phase coils 131 and 141 wound around 43 are connected to a battery 194 via drive circuits 191 and 192, respectively. The drive circuits 191 and 192 are transistor inverters each including a pair of transistors as switching elements for each phase. Drive circuit 191,
192 is connected to the control unit 190. Drive circuits 191 and 191 are controlled by control signals from the control unit 190.
When the transistor 192 is switched, a current flows between the battery 194 and the motors MG1 and MG2.
The motors MG1 and MG2 can operate as electric motors that receive the supply of power from the battery 194 to rotate and drive (hereinafter, this running state is referred to as power running) and the rotor 1
When the motors 32 and 142 are rotated by external force, the battery 194 can also be charged by functioning as a generator for generating an electromotive force at both ends of the three-phase coils 131 and 141 (hereinafter, this running state is referred to as regeneration). Call).

The engine 150 and the motors MG1 and MG2 are mechanically connected via planetary gears 120, respectively. The planetary gear 120 includes a sun gear 121,
It comprises a planetary carrier 124 having a ring gear 122 and a planetary pinion gear 123. The sun gear 121 rotates at the center. The planetary pinion gear 123 revolves while rotating around the sun gear 121. The ring gear 122 is a planetary pinion gear 123
Rotate around. The crankshaft 156 of the engine 150 is connected to the planetary carrier shaft 1 via the damper 130.
27. The damper 130 is for absorbing torsional vibration generated in the crankshaft 156. The rotor 132 of the motor MG1 is
Is joined to. The rotor 142 of the motor MG2 is connected to the ring gear shaft 126. Ring gear 122
Of the drive shaft 112 via the chain belt 129.
And wheels 116R, 116L.

The entire operation of the hybrid vehicle of the embodiment is controlled by the control unit 190. The control unit 190 has a CPU,
This is a one-chip microcomputer having a ROM, a RAM, and the like. The control unit 190 is the EFI ECU 17
0, and can communicate various information with each other. For example, the EFIECU 170 detects the engine coolant temperature with a coolant temperature sensor 154. Therefore, the control unit 190 can acquire the engine water temperature by communication. Conversely, the control unit 190 can indirectly control the operation of the engine 150 by transmitting information such as a torque command value and a rotation speed command value required for controlling the engine 150 to the EFIECU 170. Further, by controlling the switching of the drive circuits 191 and 192, the operation of the motors MG1 and MG2 can be directly controlled.

In order to realize such control, the control unit 190 includes various sensors, for example, an accelerator pedal position sensor 165 for detecting the amount of depression of the accelerator by the driver, and the number of rotations of the drive shaft 112. Are provided. Since the ring gear shaft 126 and the drive shaft 112 are mechanically connected, in this embodiment, a rotation speed sensor 144 for detecting the rotation speed of the drive shaft 112 is provided on the ring gear shaft 126 to control the rotation of the motor MG2. It is common with the sensor for.

(2) Basic operation: To explain the basic operation of such a hybrid vehicle, the operation of the planetary gear 120 will first be described. Planetary gear 12
0 indicates that the rotation state and the torque of the two rotation axes (hereinafter, collectively referred to as the rotation state) of the three rotation axes determine the rotation state of the remaining rotation axes. Have. The relationship between the rotation states of the respective rotating shafts is shown in the following equation (1).

Nr = (1 + ρ) Nc−ρNs; Nc = (Nr + ρNs) / (1 + ρ); Ns = (Nc−Nr) / ρ + Nc; Ts = ρ / (1 + ρ) × Tc; Tr = 1 / (1 + ρ) × Tc ... (1)

Here, Ns and Ts are the rotation speed and torque of the sun gear shaft 125, and Nr and Tr are the ring gear shaft 126
Are the rotation speed and torque of the planetary carrier shaft 127, and Nc and Tc are the rotation speed and torque of the planetary carrier shaft 127. Ρ is expressed by the following equation, and the sun gear 121 and the ring gear 122
Gear ratio. ρ = number of teeth of sun gear 121 / number of teeth of ring gear 122

The hybrid vehicle of this embodiment can run in various states based on the action of the planetary gear 120. For example, in a relatively low-speed state in which the hybrid vehicle has started traveling, the vehicle is driven by transmitting power to the drive shaft 112 by powering the motor MG2 with the engine 150 stopped. Similarly, the vehicle may travel with the engine 150 idling.

When the hybrid vehicle reaches a predetermined speed, control unit 190 runs motor MG1 and cranks and starts engine 150 with the torque. At this time, the reaction torque of the motor MG1 is also output to the ring gear 122 via the planetary gear 120. The control unit 190 controls the motor MG so that the required power is output from the drive shaft 112 while canceling the reaction torque.
2 is controlled. The control for starting the engine will be described later in detail.

When the engine 150 is operating,
The power is converted into various rotational speeds and torques and output from the drive shaft 112 to travel. Engine 15
0, the planetary carrier shaft 127 is rotated, and the sun gear shaft 125 is rotated under the condition satisfying the above expression (1).
And the ring gear shaft 126 rotates. Ring gear shaft 1
The power generated by the rotation of the wheel 26 remains unchanged from the wheels 116R, 116
L. Power generated by rotation of the sun gear shaft 125 can be regenerated as electric power by the motor MG1. On the other hand, if the motor MG2 is powered, power can be output to the wheels 116R and 116L via the ring gear shaft 126. When the torque transmitted from the engine 150 to the ring gear shaft 126 is insufficient, the motor MG2 is powered to assist the torque. Power regenerated by motor MG1 and power stored in battery 149 are used as power for powering motor MG2. Control unit 190 controls the operation of motors MG1 and MG2 according to the required power to be output from drive shaft 112.

The planetary gear 120 is a ring gear 12
With the 2 stopped, the planetary carrier 124 and the sun gear 121 can be rotated. Therefore, engine 150 can be operated even when the vehicle is stopped. For example, when the remaining capacity of the battery 194 decreases, the engine 150 is started and the motor MG1 is regenerated to charge the battery 194. If the motor MG1 is powered even when the vehicle is stopped, the engine 150 can be cranked and started by the torque. At this time, control unit 190 controls motor MG2 to cancel the reaction torque of motor MG1.

(3) Start control process: Next, the start control process in this embodiment will be described. The start control process refers to a process for starting the self-sustaining operation by cranking the engine 150 with the motor MG1 and injecting and igniting fuel. The start control process is performed by the control unit 190.
(Hereinafter, simply referred to as CPU), and is repeatedly executed at predetermined time intervals in addition to various control processes.
As described above, the start control process is performed when the vehicle speed and the torque of the hybrid vehicle reach the speed at which the vehicle travels from the EV traveling only using the motor MG2 to the normal traveling state using the power of the engine. Is executed. Second
Is executed when the remaining capacity of the battery 194 decreases and charging is determined to be necessary. The starting under the second condition is performed regardless of whether the vehicle is stopped or running.

When the start control processing routine is started, C
The PU controls the VVT mechanism of the engine 150 to first set the intake valve closing angle to the most retarded angle (step S100).
This setting will be described. FIG. 3 is an explanatory diagram showing the opening / closing timing of the intake valve and the exhaust valve by the VVT mechanism. In the engine 150, a piston moves up and down in a cylinder, and accordingly, a crankshaft of the engine 150 rotates in a clockwise direction in the figure.

The open / close timing of the intake valve is shown by a white arrow, and the open / close timing of the exhaust valve is shown by a solid arrow. As illustrated, the exhaust valve opens when the crankshaft is at a rotational position slightly before the bottom dead center of the piston, and closes when the crankshaft slightly exceeds the top dead center. This timing is fixed. On the other hand, at the intake valve, for example, at timing A
In, it opens before the top dead center and closes when it slightly crosses the bottom dead center. From the opening of the intake valve to a point slightly above the top dead center, both the intake valve and the exhaust valve are open. VV
When the opening / closing timing is changed by the T mechanism, only the opening / closing timing of the intake valve changes as, for example, timing B. At this time, the intake valve opens later than the timing A, slightly above the top dead center, and closes at a point far beyond the bottom dead center. Although the opening / closing timing of the intake valve is changed, the period during which the intake valve is open is the same at timing A and timing B.

The opening / closing timing of the intake valve that changes in this manner is represented by the angle from the bottom dead center to the closing of the intake valve, that is, the closing angle of the intake valve as shown in the figure. If the intake valve closing angle is adjusted to be larger than the standard value, the intake valve closes more slowly. This control is called retard control. When the retard control is performed, the stroke of compressing the air-fuel mixture sucked into the combustion chamber is shortened, so that the load for performing the cranking for starting the engine 150 is reduced. In this embodiment, in order to reduce this load in step S100, the intake valve closing angle is controlled to the most retarded angle.

Next, the CPU controls the operation of the engine (step S200). FIG. 4 is a flowchart of the engine operation control processing routine. In this process, the CP
U determines whether the engine 150 has started operation (step S202). When the engine 150 has not started operation, that is, when the fuel supply and the ignition have not been performed, the CPU ends the engine operation control processing routine. Start control processing routine (FIG. 2)
When the CPU is executed for the first time, the CPU does not execute any processing because the operation of the engine has not been started.

On the other hand, if the engine 150 has started to operate, the CPU determines whether or not the vehicle is stopped (step S204). This determination is made based on the rotation speed sensor 14.
4 can be performed based on the vehicle speed obtained using the detection signal. Further, the determination can be made based on whether or not the so-called shift lever position is at the P position used when the vehicle is stopped. Then, as described below, the operation state of the engine 150 is set according to the traveling state of the vehicle, and the control of the operation is executed.

When it is determined that the vehicle is not stopped, power corresponding to the running state is set as the required power of the engine 150. For this purpose, the CPU inputs the amount of depression of the accelerator and the vehicle speed (step S212). The amount of depression of the accelerator is detected by an accelerator opening sensor 165. The running state of the vehicle, that is, the vehicle speed and the required torque can be detected based on these various amounts. The CPU calculates the power required for traveling from the product of the vehicle speed and the required torque,
The required power Pe * of the engine 150 is set (step S214).

Next, the required power Pe * thus set
(Step S216). The gradual change process is a process for suppressing a change in the required power Pe *.
This is a process for avoiding a possibility that the driving state of the vehicle becomes unstable due to a sudden change in the required power Pe * of the engine 150. Specifically, by performing a process of multiplying each of the previous required power and the required power newly set in step S214 by a predetermined weighting coefficient to obtain a sum, that is, a so-called smoothing process, the variation of the required power is suppressed. ing. Here, an upper limit guard process is performed at the same time so that the rate of change from the previous required power to the smoothed result value is equal to or less than a predetermined value.

In the present embodiment, upper and lower limit guard processing is further performed on the required power Pe * thus set (step S218). That is, the value of the required power Pe * is corrected so as to fall within the range of “0 ≦ Pe * ≦ Pmax”. For example, when the required power Pe * is smaller than the value 0, the value 0 is set to the required power Pe *. Required power Pe
If * is greater than the value Pmax, the required power Pe *
Is set to the value Pmax. The value Pmax is an upper limit value of the required power set within a range in which the engine 150 does not cause excessive vibration and other unstable operating states at the time of starting.

After setting the required power of the engine 150 in this way, the target rotation speed Ne * of the engine 150 is set based on the operation curve (step S220). FIG.
FIG. 4 is an explanatory diagram showing an operation curve. A curve B in the figure indicates a limit value of a rotational speed and a torque at which the engine 150 can operate. Curves indicated by α1%, α2%, and the like are isoefficiency lines at which the operation efficiency of the engine 150 is constant, and indicate that the efficiency decreases in the order of α1%, α2%. As shown, the efficiency of the engine 150 is high at a relatively limited operating point, and the efficiency gradually decreases at operating points around the engine.

The curves indicated by C1, C2 and C3 are curves in which the power output from engine 150 is constant. A1, A2, A3 are curves C1, C2, respectively.
It shows that the operation efficiency becomes highest when outputting the power of C3. The curves C1 to C3 are curves that can be drawn countlessly according to the required power, and a torque and a rotation speed with high operation efficiency can be selected according to each required power. The curve depicting the countless operating points with high efficiency thus selected is the curve A in the figure,
This is called an operation curve.

In step S220 of the engine operation point setting process, a target rotation speed Ne * with good operation efficiency is selected from the operation curve. Note that FIG.
Indicates the entire operable area. The engine operating point setting process routine of FIG. 4 is a process at the time of starting the engine 150, and is a process executed when the required power is relatively low. Therefore, a relatively low rotation speed and low torque portion on the operation curve shown in FIG. 5 is used.

At the same time, the CPU turns off the idle flag (step S220). What is the idle flag?
This is a flag for instructing execution of control for idling the engine 150. The required power Pe while the vehicle is running
The operation of the engine 150 is controlled with priority given to *. Therefore, the idle flag is turned off to instruct the execution of such control.

When the driving point during traveling is set in this way, the CPU controls the operation of the engine 150 (step S222). It is the EFIECU 170 that actually controls the operation of the engine 150. Therefore,
Here, the CPU transmits the required power Pe * to the EFIECU 170
To control the operation of the engine 150 indirectly. The EFIECU 170 controls the fuel injection amount, the throttle opening, the ignition timing, the closing angle of the intake valve by the VVT mechanism, and the like according to the required power Pe *.

It is not possible to control both the required power Pe * and the rotational speed Ne * only by controlling the operation of the engine 150. The EFIECU 170 only controls the engine 150 so that the required power Pe * is output.
The number of revolutions is consequently determined according to the load applied to engine 150. When starting the engine 150 during traveling,
Since the power required for traveling is already output by motor MG2, almost no traveling load is applied to engine 150. Therefore, if only the control of step S222 is performed, the engine 150 will rotate at a very high speed. In the present embodiment, as described later, the motor MG
1 applies a load to the engine 150 so that step S2
The target rotation speed Ne * set at 20 is realized.

If it is determined in step S202 that the vehicle is stopped, the CPU executes control for operating the engine 150 in a so-called idle state. C
PU is the engine 15 detected by the water temperature sensor 154.
A water temperature of 0 is input (step S232). The CPU sets the required power of engine 150 based on the water temperature (step S234). The required power during stoppage is set in advance as a map according to the water temperature. FIG. 6 is an explanatory diagram showing a map for giving the required power Pe *. As shown, when the engine coolant temperature is lower than the predetermined temperature tmp2, the required power is set to a predetermined positive value ptmp. The required power is set to a value of 0 when the engine water temperature is equal to or higher than the temperature tmp1. Between the temperatures tmp2 and tmp1, the required power gradually changes according to the engine water temperature.

In general, when the engine water temperature is low, it is difficult to vaporize the fuel, and it is difficult to start the engine 150. In such a case, if the required power is set to a positive predetermined value, the engine 150
The amount of intake air and the amount of fuel injection are increased, and the engine 150 is easily started. In this embodiment, from this viewpoint, when the water temperature is low enough to make it difficult to start the engine 150 (t in FIG. 6).
mp1 or lower), the required power is set to ptmp. In the present embodiment, the temperature tmp1 is set to −10 ° C.,
temp2 is set to −20 ° C., and ptmp is set to 4 kW. For these parameters, appropriate values may be selected according to the type of engine to be mounted.

Next, the CPU sets the target rotation speed Ne * of the engine 150 (step S236). The target rotation speed Ne * is set in advance as a map of the engine water temperature, similarly to the required power. FIG. 7 is an example of a map for giving the target rotation speed Ne *. As illustrated, when the engine coolant temperature is equal to or lower than a predetermined value tmp3, the target rotation speed Ne * is set to the value Nt1. When the engine water temperature exceeds tmp3, the target rotation speed Ne * gradually decreases, and when the engine water temperature is equal to or higher than tmp4, the target rotation speed Ne * becomes the value Nt2. When the engine water temperature is relatively low, a slightly higher rotation speed is set as the target rotation speed in order to promote warm-up of the engine 150.
In this embodiment, the value Nt1 is 1300 rpm, and the value Nt2 is 1
000 rpm. These values may be appropriately selected according to the type of the engine to be mounted.

At the same time, the CPU turns on the idle flag (step S236). When idling the engine 150, unlike the control described in step S222, the EFIECU 170 controls the operation of the engine 150 so that the engine 150 rotates at the target rotational speed. CP
U turns on the idle flag to instruct the execution of such control.

When the target rotational speed is set in this way, CP
U executes control for idling the engine 150 at the rotation speed (step S238). As already explained,
The CPU indirectly controls the operation of engine 150 by transmitting necessary information to EFIECU 170. Here, since the idle flag is on, the EFIECU 170 controls the fuel injection amount, the throttle opening, the intake valve closing angle by the VVT mechanism, and the like according to the rotation speed of the engine 150. From the CPU, the flag for instructing the execution of the control and the target rotation speed Ne * are set to E.
Output to FI ECU 170. When the operation of the engine 150 is controlled in accordance with the running state of the vehicle, the CPU ends the engine operation control processing routine and returns to the start control processing routine (FIG. 2).

In the start control processing routine, the motor M
The control of the operation of G1 is executed (step S300). FIG. 8 is a flowchart of a MG1 torque T1 setting processing routine. When this process is started, the CPU determines whether or not the rotational speed of the engine 150 is higher than a predetermined rotational speed Netag (hereinafter, referred to as an ignition rotational speed) as a criterion for determining whether or not to perform ignition (hereinafter, referred to as an ignition rotational speed). Step S302). E
The FIECU 170 controls the ignition timing based on the rotation speed Ne of the engine 150. Therefore, the rotation speed Ne of the engine 150 can be detected by communication with the EFIECU 170. As the predetermined rotation speed Netag, a rotation speed suitable for ignition may be set according to the type of the engine. In the present embodiment, the value of Netag is set to a value substantially equal to the idle speed, that is, 1000 rpm, in order to avoid a large fluctuation in the speed due to the start.

When the rotation speed Ne is equal to or lower than Netag, control for gradually increasing the torque T1 of the motor MG1 at a predetermined change rate (hereinafter referred to as ramp control) is executed. Therefore, the CPU increases the torque T1 of the motor MG1 by a predetermined increment Δ
It is increased by T (step S310). In addition, an upper limit guard process is performed on the torque T1 so as not to exceed the predetermined maximum value Tmax (step S312).

When the rotation speed of engine 150 is relatively low, even if a large torque is output from motor MG1 due to the effect of inertia, the rotation speed of engine 150 does not increase. Setting the required torque of the motor MG1 to a large value in such a state leads to wasteful power consumption. In this embodiment, from this point of view, the rotational speed Ne is set to Net
If the value is equal to or less than ag, the motor MG1 is controlled by the ramp.

On the other hand, when the rotational speed Ne of the engine 150 is Ne
If it is larger than the tag, the CPU performs feedback control of the torque of the motor MG1. This feedback control is performed so that the rotation speed Ne of the engine 150 matches the predetermined target rotation speed N1 *. However, a different value is applied to the target rotation speed N1 * depending on the running state of the vehicle. C
The PU determines whether or not the vehicle is stopped (step S
320), if the vehicle is not stopped, the value Ne * is substituted for the target rotation speed N1 * (step S322). This value is the value set in step S220 of the engine operation control process (FIG. 4). When the vehicle is stopped, the target rotation speed N
A value obtained by subtracting a predetermined value α from the value Ne * is set as 1 * (step S324). In this embodiment, as described later, the predetermined value α is set to about 30 to 50 rpm.

As described above, during running of the vehicle, unless a load is applied to engine 150 by motor MG1, engine 150 will be operated at a very high speed. The target rotation speeds N1 * and Ne * are the engine 1
This is a value lower than the rotation speed realized by the control of F.50. On the other hand, when the vehicle is stopped, the engine 150 is controlled to operate at the target rotation speed Ne *. Step S3
As described in 22, by setting a value obtained by subtracting the predetermined value α from the value Ne *, the target rotation speed N1 * becomes a value lower than the rotation speed realized by controlling the engine 150. As described above, in the present embodiment, the target rotation speed N1 * used for calculating the torque of the motor MG1 is set to a value lower than the rotation speed realized by the control of the engine 150 regardless of the running state of the vehicle. .

Next, the CPU determines the deviation Δ between the thus set target rotation speed N1 * and the rotation speed Ne of the engine 150.
Based on nc, a torque T1 of motor MG1 is set by the following equation (step S326). T1 = k1Δnc + k2２ (Δnc) Δnc = N1 * −Ne

The above equation shows that the motor M
This is an equation for setting the torque of G1. Proportional term (first term on right side) and integral term (second term on right side) of rotational speed deviation Δnc
Sets the torque T1. k1 and k2 are constant coefficients previously set as gains through experiments or analysis. When rotation speed Ne of engine 150 is higher than target rotation speed N1 *, torque T1 of motor MG1 is
Has a negative value and a low value has a positive value. Since the PI control is a well-known technique, further detailed description will be omitted. The CPU executes a gradual change process on the torque T1 set in this manner (step S328). Motor T1
This is for avoiding a sudden change in the torque of the motor and an unstable operation state.

When the torque T1 of MG1 is set by the above processing, the CPU controls the operation of the motor MG1 (step S330). The CPU sets a voltage to be applied to the three-phase coil of the motor MG1 according to the torque T1.
PWM control is performed on and off of each transistor constituting the drive circuit 191 so that this voltage value is applied to the three-phase coil at a phase corresponding to the rotation speed of the motor MG1. Motor M
The same applies when the torque of G1 is negative, that is, when the motor MG1 is regenerated. Since the PWM control of the synchronous motor is a known technique, a detailed description is omitted.

In parallel with the control of the motor MG1, the CPU measures the elapsed time from when the target torque T1 became negative (step S332). This is the measurement of the time that is continuously negative. Therefore, if the target torque T1 becomes a negative value and then changes to a positive value again, the elapsed time becomes zero.
Is initialized to After executing the above processing, the CPU ends the motor MG1 control processing routine and returns to the start control processing routine (FIG. 2).

Thereafter, the CPU executes a process for controlling the operation of motor MG2 (step S400). Motor M
G2 is controlled to output necessary power to the drive shaft 112 while canceling the reaction force due to the torque of MG1. When torque T1 is output from motor MG1, the reaction force is output to ring gear 122 according to equation (1) shown above. When the vehicle is stopped, the torque that offsets this reaction
This is set as the target torque of G2. When the vehicle is traveling, a value obtained by adding a torque required for traveling to a torque for canceling the reaction force is set as the target torque of motor MG2. The CPU performs PWM control on / off of each transistor included in the drive circuit 192 so that a voltage corresponding to the target torque thus set is applied to the three-phase coil of the motor MG2.

With the above processing, the rotation speed of the engine 150 changes every moment. If the rotation speed of the engine 150 is low at the beginning of the start control processing routine, the rotation speed of the engine 150 is gradually increased by ramp-controlling the torque of the motor MG1. The CPU determines that the rotation speed Ne of the engine 150 fluctuating in this manner is equal to the ignition rotation speed Ne
It is determined whether it is equal to or larger than the tag (step S50).
0), if the ignition speed is equal to or higher than Netag, the fuel injection to the engine 150 and the ignition process are executed (step S600). As described above, the instruction to start the operation of the engine 150 by executing such processing is given by the EF.
This is output to the IECU 170. Of course, if the operation of the engine 150 has already been started, this process is not performed. Also, the rotation speed Ne of the engine 150
This process is not performed even when is lower than the ignition rotation speed Netag.

Next, the CPU determines whether or not the elapsed time from when the torque T1 of the motor MG1 becomes negative exceeds a predetermined value Ts as the complete explosion determination of the engine 150 (step S700). The complete explosion determination is a determination as to whether or not the engine 150 has started self-sustaining operation. Engine 150
Starts self-sustaining operation, the operation of engine 150 is controlled by the engine operation control process (step S200). As a result, the engine 150 is controlled to rotate at a rotation speed higher than the target rotation speed N1 * which is a reference for calculating the torque of the motor MG1.

On the other hand, the motor MG1 is connected to the engine 15
A negative torque is output so as to reduce the number of revolutions of 0 to the target number of revolutions N1 *. When the engine 150 is not operating independently, the engine 150 is connected to the motor MG1.
Cannot maintain the rotation speed of N1 * or more under a load. Therefore, a complete explosion determination can be made based on whether or not the period during which the torque T1 of the motor MG1 is negative exceeds the predetermined value cs. If the predetermined value cs has been exceeded, the CPU 150 determines that the engine 150 has started self-sustaining operation, and the CPU ends the start control processing routine. If the value is equal to or smaller than the predetermined value cs, it is determined that the engine 150 is not performing the self-sustaining operation, and the CPU repeatedly executes the processing of steps S200 to S600. The predetermined value cs is based on changes in the engine speed at the time of starting, the torque of the motor MG1, and the like.
It can be preset experimentally or analytically as shown below.

The state of changes in the engine speed, the torque of the motor MG1, and the like accompanying the start control processing of this embodiment will be described. FIG. 9 is an explanatory diagram showing a change in the engine speed and the like when the start control process is executed during the running of the vehicle. As illustrated, when the start control of the engine 150 is started at the time t1, the torque of the motor MG1 increases at a constant rate to the maximum torque Tmax (step S31 in FIG. 8).
0, S312). The rotation speed of engine 150 is gradually increased by the torque of motor MG1.

Thus, at time t2, engine 150
When the rotation speed reaches a predetermined ignition rotation speed Netag, the supply of fuel to the engine 150 and the ignition are performed. After reaching the ignition rotation speed Netag, the torque of the motor MG1 is set by PI control (step S32 in FIG. 8).
0 to S328). While the vehicle is running, the speed is set based on the deviation between the target rotation speed Ne * of the engine 150 and the actual rotation speed Ne. In a section from time t2 to time t3, since the engine speed is lower than the target speed Ne *, the motor MG
The torque of 1 has a positive value.

At time t3, when the rotation speed of engine 150 reaches target rotation speed Ne *, the torque of motor MG1 turns negative. In this case, if the engine 150 has not started the self-sustaining operation, the rotational speed of the engine 150 falls to a value Ne * or lower, as indicated by a broken line in the figure. Therefore, the torque of the motor MG1 immediately returns to a positive value again.

On the other hand, if engine 150 has started self-sustaining operation, engine 150 is controlled to output power Pe *. Therefore, the rotation speed of engine 150 increases. Motor MG1 determines the number of revolutions of engine 150 as value Ne *.
Output a negative torque to reduce the Thus, the torque of the motor MG1 has a negative value for a while until the rotation speed of the engine 150 is stabilized at the value Ne *.

At time t3, when the torque of motor MG1 turns negative, the complete explosion determination counter starts measuring the elapsed time. If the engine 150 has started the self-sustaining operation, the complete explosion determination counter increases at a constant rate as shown. When the elapsed time exceeds a predetermined value cs at time t4, the CPU determines that the engine 150 has started the self-sustaining operation, and ends the start control.

The elapsed time cs, which is the reference for the complete explosion determination, is set to an appropriate value that can determine that the engine 150 has started self-sustaining operation based on such fluctuations in the rotational speed and the like. For example, if the elapsed time cs is set to a small value, the engine 150 starts the self-sustaining operation due to the torque fluctuation of the motor MG1 when the engine 150 has not started the self-sustaining operation as shown by the broken line in FIG. May be erroneously determined to be. On the other hand, if the value cs is set to a large value, the time required for the complete explosion determination becomes longer. Further, depending on the response of the control until the rotation speed of engine 150 stabilizes at Ne *, the torque of motor MG1 may be
There is a possibility that it may turn positive, and there is a possibility that an erroneous determination will be caused.
In the present embodiment, the elapsed time cs is set to several seconds in consideration of these conditions. Note that the elapsed time cs may be changed according to the engine water temperature or the like.

Next, the setting of the target rotation speed N1 * used for setting the torque T1 of the motor MG1 while the vehicle is stopped will be described. FIG. 10 is an explanatory diagram showing a change in the engine speed and the like when the start control process is executed while the vehicle is stopped. As in the case of traveling, when the start control is started at time t11, the torque T1 of the motor MG1 becomes the maximum value Tmax.
To rise. When the rotation speed of engine 150 reaches value Netag at time t12, fuel supply and ignition are performed, and engine 150 starts operating. Thereafter, the operation of the motor MG1 is controlled by PI (step S in FIG. 8).
300-S328).

In the section from time t12 to time t13, since the rotation speed of engine 150 is lower than target rotation speed N1 * of PI control, the torque of motor MG1 has a positive value. When the rotation speed of engine 150 exceeds target rotation speed N1 *, the torque of motor MG1 turns negative. Here, if the engine 150 has not started the self-sustaining operation, the rotation speed of the engine 150 immediately decreases, and the torque of the motor MG1 becomes a positive value again. This is the same as the change during traveling (see FIG. 9).

On the other hand, when the engine 150 has started the self-sustaining operation, the engine 150 is controlled to perform the idle operation while the vehicle is stopped (see FIG. 4). The engine 150 is controlled to rotate at the idle speed Ne *. On the other hand, motor MG1 is controlled to operate engine 150 at target rotation speed N1 * lower than idle rotation speed Ne *. Due to the interaction between the two controls, the torque of the motor MG1 continuously becomes a negative value. As a result, at time t13
Thereafter, the complete explosion judgment counter increases at a constant rate of change. At time t14, when the elapsed time exceeds a predetermined value cs, the CPU determines that the engine 150 has started the self-sustaining operation, and ends the start control process.

The control by which the EFIECU 170 idles the engine 150 is usually to provide a predetermined dead zone in order to prevent the operating state of the engine 150 from frequently changing. That is, the control of the idling operation is usually performed such that the rotation speed of the engine 150 falls within a predetermined range with respect to the idle rotation speed Ne *. When the target rotation speed N1 * is equal to the idle rotation speed Ne * as the target rotation speed N1 * falls within the dead zone, the torque T1 of the motor MG1 becomes substantially 0 when the engine 150 starts the self-sustaining operation. It cannot be executed.

On the other hand, if the target rotation speed N1 * is set to an extremely lower value than the idle rotation speed Ne *, the motor MG1
Depending on the load, the operation of the engine 150 may become unstable or stop. Further, in the configuration in which the engine 150 and the motor MG1 and the like are connected via the planetary gear 120 as in the present embodiment, it is also known that rattling noise occurs in the planetary gear 120 when the target rotation speed N1 * is set to a low value. . Further, it is also known that when the target rotation speed N1 * is set to a low value, the rotation of the engine 150 becomes unstable, resulting in so-called torsional resonance. In the present embodiment, in consideration of these conditions, the target rotation speed N1 * is set in a range that does not hinder the operation of the engine 150, and is 30 to 50 rpm lower than the idle rotation speed Ne *.
A value lower by about pm is set as the target rotation speed N1 *. That is, the value α in step S324 of FIG.
rpm.

According to the hybrid vehicle of the present embodiment described above, the complete explosion of the engine 150 can be accurately determined, and the engine 150 can be started properly. Therefore, power consumption at the time of starting the engine 150 can be suppressed. In addition, since the engine 150 can be started quickly and reliably, the responsiveness of the running vehicle can be improved.

In the hybrid vehicle of this embodiment,
When the vehicle is stopped, the engine 150 can be started with the required power of 0 as the value 0. As a result, the engine 150
Vibration can be reduced. Further, fuel consumption and emission at the time of starting can be suppressed.

In the hybrid vehicle of this embodiment, the target speed N1 * for setting the torque of the motor MG1 is set to a value lower than the idle speed Ne * of the engine 150 while the vehicle is stopped, so that the motor MG1 is stopped. Complete explosion judgment based on the torque of As a result, it is possible to start the engine 150 with the required power set to the value 0, and to obtain the various effects described above. The hybrid vehicle has characteristics that are excellent in fuel consumption and emission, and the above-described effects further improve these characteristics.

In the hybrid vehicle of this embodiment, the required power is set to a positive value when the engine water temperature is low. Therefore, when the temperature is low, the engine can be started properly. During traveling, the engine 150 is started with the required power according to the traveling state. Therefore, the engine 15
As soon as the engine is started, the power required for traveling can be output quickly, the power consumption of the battery can be suppressed, and the responsiveness of the vehicle can be improved.

This embodiment has exemplified a hybrid vehicle to which the planetary gear 120 is applied. Regardless of this, the present invention is applicable to hybrid vehicles having various configurations. FIG. 11 is an explanatory diagram illustrating a configuration of a hybrid vehicle as a modification. This hybrid vehicle includes a clutch motor CM instead of planetary gear 120 and motor MG1. The clutch motor includes an inner rotor 202 and an outer rotor 2 that are relatively rotatable.
04 is a paired rotor motor. As shown in FIG. 11, the inner rotor 202 is connected to the crankshaft 156 of the engine 150, and the outer rotor 204 is connected to the drive shaft 112. Electric power is supplied to the outer rotor 204 via a slip ring 206. The motor MG2 is also connected to the shaft on the outer rotor 204 side. Other configurations are the same as those of the hybrid vehicle of the present embodiment.

The power output from engine 150 can be transmitted to drive shaft 112 via clutch motor CM. The clutch motor CM includes the inner rotor 202
Power is transmitted between the motor and the outer rotor 204 via an electromagnetic coupling. At this time, if the rotation speed of the outer rotor 204 is lower than the rotation speed of the inner rotor 202, electric power corresponding to the slippage between the two can be regenerated by the clutch motor CM. Conversely, if electric power is supplied to the clutch motor CM, the rotation speed of the inner rotor 202 is increased and the drive shaft 11
2 can be output. The torque output from the engine 150 via the clutch motor CM is
If it does not match the required torque to be output from the motor MG2, it can be compensated by the motor MG2.

Further, if the clutch motor is run, the engine 150 can be started by motoring.
At the time of motoring, a reaction torque is output to the axle based on the principle of action and reaction between the inner rotor 202 and the outer rotor 204. This reaction torque is equal to the motor MG
It can be offset by 2. If the present invention is applied to the first hybrid vehicle, the clutch motor C
It is possible to determine the complete explosion of the engine 150 based on the torque of M.

The present invention can be applied not only to a parallel hybrid vehicle capable of directly outputting the power of the engine 150 to the drive shaft, but also to a so-called series hybrid vehicle. FIG. 12 is an explanatory diagram showing the configuration of the series hybrid vehicle. In the series hybrid vehicle, the crankshaft of engine 150 is mechanically coupled to the rotating shaft of generator G. Engine 150 is not coupled to the drive shaft. By operating the engine 150, electric power can be generated by the generator G. The generated power is stored in a battery. On the other hand, a motor M is coupled to the drive shaft. The motor M rotates by the electric power of the battery.

In a series hybrid vehicle, the engine 150 is operated / stopped according to the charged amount of the battery. When the power of the battery is consumed and charging becomes necessary, the engine 150 is started to start charging. The starting is performed by cranking the engine 150 with the generator G. If the present invention is applied to such a series hybrid vehicle, it is possible to determine the complete explosion of the engine 150 based on the torque of the generator G at the time of such starting.

In addition, the present invention is applicable not only to a hybrid vehicle but also to a normal vehicle using only an engine as a power source. In addition, regardless of the vehicle, various devices equipped with an engine as a power source may be applied to a start control device that starts the operation of the engine.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can be implemented in various forms without departing from the gist of the present invention. Of course. For example, in the above embodiment, various controls are executed by software, but these may be realized by hardware.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of a hybrid vehicle as an embodiment of the present invention.

FIG. 2 is a flowchart of a start control processing routine.

FIG. 3 is an explanatory diagram showing a closing angle of an intake valve.

FIG. 4 is a flowchart of an engine operation control processing routine.

FIG. 5 is an explanatory diagram showing an operation curve.

FIG. 6 is an explanatory diagram showing a relationship between engine water temperature and required power.

FIG. 7 is an explanatory diagram showing a relationship between an engine water temperature and a target rotation speed.

FIG. 8 is a flowchart of an MG1 operation control processing routine.

FIG. 9 is an explanatory diagram showing a change in an engine speed and the like when a start control process is executed while the vehicle is running.

FIG. 10 is an explanatory diagram showing a change in an engine speed and the like when a start control process is executed while the vehicle is stopped.

FIG. 11 is an explanatory diagram showing a configuration of a hybrid vehicle as a modification.

FIG. 12 is an explanatory diagram showing a configuration of a series hybrid vehicle.

[Explanation of symbols]

 112 ... drive shaft 116R, 116L ... wheels 119 ... case 120 ... planetary gear 121 ... sun gear 122 ... ring gear 123 ... planetary pinion gear 124 ... planetary carrier 125 ... sun gear shaft 126 ... ring gear shaft 127 ... planetary carrier shaft 129 ... chain belt 130 ... damper 131 141, three-phase coils 132, 142, rotors 133, 143, stator 144, rotational speed sensor 149, battery 150, engine 154, water temperature sensor 156, crankshaft 165, accelerator opening sensor 190, control units 191, 192, drive Circuit 194 ... Battery 202 ... Inner rotor 204 ... Outer rotor 206 ... Slip ring

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) F02N 15/00 F02N 15/00 E // B60K 6/00 B60K 9/00 Z 8/00 F term (reference ) 3D041 AA28 AA31 AA36 AB01 AC15 AD00 AD01 AD02 AD10 AD14 AE02 AE04 AE07 AE09 AF00 AF03 3G084 BA05 BA13 BA17 BA23 CA01 CA09 DA09 EB08 EB25 EC05 FA10 FA20 FA32 FA33 FA36 3G093 AA07 A04 DA05 DA01 EA05 EA09 EA13 EB00 EB09 EC01 EC02 FA00 FA08 FA10 FB01

Claims (8)

[Claims] 1. A start control device for rotating an engine by the power of an electric motor coupled to the engine, supplying fuel and igniting the engine to make the engine self-sustained, comprising: Power setting means for setting power, engine control means for controlling the operation of the engine in an operation state corresponding to the required power, and engine rotation realized by the engine control means within a range that does not hinder the operation of the engine. Starting comprising: motor control means for rotating the motor at a motor target speed significantly lower than the number of motors; and independent operation determination means for determining whether the engine has started independent operation based on the torque of the motor. Control device. 2. The start control device according to claim 1, wherein said power setting means is means for setting said required power to a value 0, and said engine control means is configured to control said engine at a predetermined engine speed. A starting control device that is a means for rotating the motor. 3. The start control device according to claim 2, further comprising a temperature detecting means for detecting a temperature of the engine, wherein the power setting means determines the temperature in accordance with ease of ignition of the engine. A starting control device which is means for setting the required power to a positive predetermined value when the required power is equal to or less than a predetermined value. 4. A hybrid vehicle equipped with an engine and a first electric motor as power sources, and running while controlling start and stop of the engine by a second electric motor coupled to the engine. Engine ignition control means for controlling the second electric motor to rotate the engine in response to a request to start the engine, and for supplying and igniting fuel to the engine; Power setting means for setting power; engine control means for operating the engine in an operating state corresponding to the required power; and an engine speed realized by the engine control means within a range that does not hinder the operation of the engine. Motor control means for rotating the second electric motor at a significantly lower electric motor target rotation speed, based on the torque of the second electric motor. Hybrid vehicle and a self-sustained operation determining means for determining whether the engine has started autonomous operation Te. 5. The hybrid vehicle according to claim 4, wherein said power setting means is means for setting said required power to a value of 0, and said engine control means controls said engine at a predetermined engine speed. A hybrid vehicle that is means for rotating. 6. The hybrid vehicle according to claim 5, further comprising a temperature detecting means for detecting a temperature of the engine, wherein the power setting means determines the temperature in accordance with ease of ignition of the engine. A hybrid vehicle that is means for setting the required power to a positive predetermined value when the value is equal to or less than the value. 7. The hybrid vehicle according to claim 5, further comprising stop determination means for determining whether or not the vehicle is stopped, wherein the power setting means determines whether the vehicle is not stopped. A hybrid vehicle which is means for setting the required power to a positive predetermined value. 8. A control method for rotating an engine by the power of an electric motor coupled to the engine, supplying fuel and igniting the engine to operate the engine independently, and (a) when the engine is operated independently. Setting the required power, (b) controlling the operation of the engine in an operating state corresponding to the required power, and (c) realizing the engine control means within a range that does not hinder the operation of the engine. (D) rotating the motor at a motor target speed significantly lower than the engine speed to be performed; and (d) determining whether the engine has started self-sustaining operation based on the torque of the motor. Control method to be provided.