JP2001193612A - Engine starter, engine starting method and hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ease an uncomfortable feeling of a passenger at the time of starting an engine by an engine starting motor and a drive motor. SOLUTION: When required to start an engine, if a speed (v) is a reference speed SPD1, the engine 10 is started by a drive motor 20 used as a power source for a vehicle. In this case, the revolution of the drive motor 20 is transmitted to the engine 10 by gradually engaging a clutch 38, and engine power is transmitted to a driving wheel after starting the engine. On the other hand, if the speed (v) is not more than the reference speed SPD1, the engine 10 is started by carrying out various controls such as a fuel injection control to start the engine and the like, while cranking the engine 10 by a starter motor 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technique for starting an engine in a configuration having an engine and an electric motor as power sources.

[0002]

2. Description of the Related Art In recent years, hybrid vehicles using an engine and an electric motor as power sources have been proposed. In such a hybrid vehicle, in addition to being able to run on either the engine or the electric motor, it is also possible to run using the engine and the electric motor in combination while driving with the electric motor due to insufficient torque or the like. Further, while the vehicle is stopped, the engine is stopped, the vehicle is started by the electric motor while the engine is stopped, and then the engine is started as needed. Since the engine is frequently stopped and started during the operation of the vehicle, various proposals have been made for starting the engine.

For example, in Japanese Patent Laid-Open No. Hei 10-136508, an engine is started by an electric motor mounted as a power source. If it is difficult to start the engine with the electric motor due to a shortage of the battery charge, the engine is started with a starter motor for starting the engine.

[0004]

However, the following problems have been pointed out in the prior art proposed in the above publication. When the engine is started by an electric motor while the vehicle is running, since the electric motor can generate a high torque because it is used for traveling,
The engine can be started quickly. The power of the engine thus started is transmitted to the vehicle drive shaft. This engine power is relatively large from the beginning because it is generated by rotation of an electric motor capable of generating high torque. As a result, the engine power that has not been transmitted is transmitted, so that a shock occurs in the vehicle due to the power transmission. This shock tends to increase as the vehicle speed decreases when power of the same magnitude is transmitted.
Occasionally, passengers may feel uncomfortable due to shock.

[0005] The present invention has been made to solve these problems, and has as its object to alleviate the occupant's discomfort when the engine is started.

[0006]

In order to solve at least a part of the above-mentioned problems, an engine starting device according to the present invention includes an engine as a power source of a moving body, and an engine for starting the engine. A starter motor, an electric motor used as a power source other than the engine and capable of starting the engine, and start control means for starting the engine, wherein the start control means comprises: An engine start by the electric motor and an engine start by the electric motor for start are selectively executed in accordance with a moving state of a moving body, and when the moving state is lower than a predetermined state, the engine start by the electric motor for starting is preferentially executed. It is characterized by having means for performing.

Further, the engine starting method of the present invention comprises a starting motor for starting an engine as a power source of a moving body, and a motor used as a power source other than the engine and capable of starting the engine. An engine starting method for starting the engine using the method, wherein a step of detecting a moving state of the moving body, and when the detected moving state is lower than a predetermined state, starting the engine by the electric motor and starting the engine. Of the engine start by electric motor,
Prioritizing execution of the engine by the starting motor.

Further, a hybrid vehicle according to the present invention is provided with an engine and an electric motor as power sources, and has the electric motor as an electric motor capable of starting the engine. The hybrid electric vehicle further includes a starting electric motor for starting the engine. Means for detecting the moving state of the vehicle, and when the detected moving state is less than a predetermined state, the engine starting by the electric motor and the engine starting by the starting electric motor,
Means for prioritizing execution of the engine by the starting motor.

In each of the present inventions having the above-described structure, when the moving condition is lower than a predetermined condition, for example, when the speed is lower than a predetermined speed, the engine starting by the starting motor is preferentially executed, and the motor is started by the motor. Do not start the engine. Since the starting motor is for starting the engine, the power of the engine after starting is smaller than that in the case of starting the engine by the electric motor as the power source. In addition, since the engine is started by the starting motor at a low speed, the power of the engine started by the starting motor is also reduced. Therefore, even if this engine power is transmitted to the vehicle or the moving body, the shock due to the transmission of the engine power can be reduced, so that the occupant is less likely to feel uncomfortable due to the power transmission shock.

At a high speed exceeding a predetermined speed, the engine is started by the electric motor, and relatively large engine power is transmitted. However, since the speed at this time is high, it is difficult for the occupant to feel uncomfortable feeling due to the power transmission shock. in this case,
It is preferable to gradually transmit the power of the engine started by the electric motor, because the engine power can be smoothly transmitted and the above-mentioned discomfort can be further reduced.

Further, although the engine is started by the starting motor, its execution opportunity is limited to a low speed running at a predetermined speed or less. Therefore, the frequency of executing the engine start by the starting motor can be reduced, and a small starting motor having a simple structure can be used.

In each of the above-described embodiments of the present invention, it is possible to adjust a predetermined speed when selectively using the engine start by the starting motor and the engine starting by the motive motor. This makes it possible to lower the frequency of execution of the engine start by the starting motor.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a calling name according to the present invention will be described based on an embodiment. FIG. 1 is an explanatory diagram showing a schematic configuration of a power system of a hybrid vehicle as an embodiment.

As shown, the hybrid vehicle of the embodiment includes an engine 10, a planetary gear 30, a traveling motor 20, and a continuously variable transmission (hereinafter referred to as CVT) 40 as main mechanisms for outputting power. . Engine 1
0 is a gasoline engine. The traveling motor 20 is a three-phase synchronous motor having a permanent magnet attached to the outer periphery of the rotor, and is driven by electric power of a battery 22 supplied through an inverter 21 functioning as a driving circuit. When the traveling motor 20 is rotated by an external force, the traveling motor 20 functions as a generator and can charge the battery 22 with the obtained power. In the following description, such an operation state in which the motor is driven by electric power is referred to as power running operation, and an operation state in which the motor is rotated by an external force to function as a generator is referred to as regenerative operation.

The planetary gear 30 includes a sun gear 31 that rotates at the center, pinion gears 32a and 32b that revolve while rotating around the sun gear 31, and these pinion gears 32.
a, a planetary carrier 33 rotatably supported by a shaft 32b
And a ring gear 36 that rotates on the outer periphery of the pinion gear 32b. In the planetary gear 30 having such a configuration, the sun gear 31 and the planetary carrier 3
3. It is known that the rotation speed and the torque of the ring gear 36 are represented by the following relational expressions. Ns = Nc · (1 + ρ) / ρ−Nr / ρ; Nc = Ns · ρ / (1 + ρ) + Nr / (1 + ρ); Nr = (1 + ρ) · Nc−ρNs; Ts = Tc · ρ / (1 + ρ) = ρ Tr: Tr = Tc / (1 + ρ); ρ = number of teeth of sun gear / number of teeth of ring gear;

Here, Ns is the number of revolutions of the sun gear 31; T
s is the torque of the sun gear 31; Nc is the rotation speed of the planetary carrier 33; Tc is the torque of the planetary carrier 33; Nr is the rotation speed of the ring gear 36;

The CVT 40 has a configuration in which a belt 43 is hung between two pulleys 41 and 42. Pulley 4
The effective radii 1 and 42 are configured to be variable by adjusting the width thereof by a hydraulic mechanism (not shown). Pulley 4
When the widths of the belts 43 are continuously changed,
Since the effective radius of the portion where the first and second portions are connected to each other changes continuously, the reduction ratio of power transmission can be changed steplessly.

The connected state of the engine 10, the planetary gear 30, the traveling motor 20, and the CVT 40 is as follows. The crankshaft 11 is connected to a sun gear 31. The traveling motor 20 is connected to a planetary carrier 33. Rotary plates 35 and 39 for inputting power are coupled to the pulley 41 of the CVT 40, and the planetary carrier 33 is configured to be coupled to and decoupled from the rotary plate 35 via a first clutch 34. The ring gear 36 is connected to the rotating plate 3 via a second clutch 38.
9 can be connected and disconnected. The ring gear 36 has a brake 37 for stopping its rotation.
Is also provided. A pulley 42 of the CVT 40 has a differential gear 5 on an axle 52 to which wheels 53 are coupled.
A drive shaft 50 capable of transmitting power via the drive shaft 1 is connected. By switching the engagement states of the clutches 34 and 38 and the brake 37, the hybrid vehicle of the present embodiment can input the power from the engine 10 and the driving motor 20 to the CVT 40 in various modes to be described later. The output can be output to the axis 50. Then, the rotation of the drive shaft 50 is transmitted to the wheels 53 via the differential gear device 51, and the wheels are rotated. In this case, the first and second clutches 34 and 38 have a multi-plate type hydraulic clutch structure having a plurality of mutually combined clutch plates and a hydraulic actuator for applying a pressing force to the clutch plates. The clutch is engaged and released by pressing and releasing the plate. The same applies to the brake 37.

In the hybrid vehicle of the embodiment, in addition to a system for outputting power, a mechanism for starting the engine 10,
Further, a mechanism for driving the auxiliary machine 12 is provided. The accessory 12 includes an air conditioner, an oil pump, and the like. The accessory 12 is connected to the engine 10 and the starter motor 14 by a transmission mechanism using a belt 13. The starter motor 14 is a three-phase synchronous motor in which a permanent magnet is attached to a rotor, and transmits rotational power in only a predetermined rotational direction to the belt 13 via a one-way clutch 15. By switching the inverter 16, more specifically, by switching each switching element in the inverter at an appropriate timing, if the starter motor 14 is powered by the power of the battery 22, the engine 10 is cranked by the power and the engine 10 is started. can do. Since the starter motor 14 is a synchronous motor and can control the number of revolutions with high accuracy, the number of revolutions of the engine 10 can be smoothly increased and a smooth start can be realized. On the other hand, when the engine 10 is operating, the auxiliary machine 12 is driven by transmitting its power by the transmission mechanism. When it is necessary to drive the auxiliary machine 12 when the operation of the engine 10 is stopped,
The starter motor 14 is powered, and the power of the
2 is driven. At this time, the engine 10 is idled.

The configuration of the inverter 16 serving as a drive circuit for the starter motor 14 will be described. FIG. 2 is a circuit diagram of the inverter. Inverter 16 is configured as a transistor inverter. U of the starter motor 14,
In the V and W phases, a total of six transistors (Tu +, Tu−, Tv +, Tv−, Tw +, Tw +,
Tw-) is provided. Each transistor has a flywheel diode (Du +, Du−, Dv +, Dv +).
−, Dw +, Dw−). These transistors include switching control signals VU, VV,
VW is input from the control unit 60. The control signal input for each phase is inverted high / low by the inverters INU, INV, INW with respect to the transistor on the sink side and then input. Therefore, the transistors on the source side and the sink side are switched so that one is high and the other is low. When each transistor of the inverter 16 is so-called PWM controlled, the pseudo three-phase alternating current becomes U,
The flow starts in the V and W phases, and the starter motor 14 rotates. In addition,
Although a shutdown signal for turning off all transistors and a signal for dead time control are also input from the control unit 60 to the inverter 16, they are not illustrated here. The inverter 21 that drives the traveling motor 20 has the same configuration as the inverter 16, and is PWM-controlled by a control signal from the control unit 60.

The control unit 60 has a CPU, RA
The microcomputer is configured as a microcomputer including an M and a ROM, and plays a role of comprehensively controlling the power system of the hybrid vehicle including the inverters 16 and 21. FIG.
Signals exchanged with the control unit 60 are shown by broken lines. The objects controlled by the control unit 60 are the engine 10, the clutches 34 and 38, the brake 37, and the CVT 40 in addition to the inverters 16 and 21.
In order to realize these controls, the control unit 60 includes a rotation speed sensor 17 for detecting the rotation speed of the starter motor 14, a vehicle speed sensor 54 for detecting the vehicle speed based on the rotation speed of the wheels 53, Signals from various sensors such as an outside air temperature sensor 55 for detecting the outside air temperature are input. The rotation speed sensor 17, the vehicle speed sensor 54,
The sensors other than the outside air temperature sensor 55 are not shown in FIG.

Next, a general operation related to the output of power in the hybrid vehicle of the present embodiment will be described. FIG. 3 is an explanatory diagram showing engagement states of the clutches 34 and 38 and the brake 37 in each operation mode. These engagement states are switched according to the operation of a shift lever (not shown) by the driver, the vehicle speed, the state of charge of the battery 22, and the like. Note that the process when starting the engine 10 will be described later.

When the shift lever is in a forward shift position called a B range or a D range, three types of operation modes, an electric torque converter (ETC) mode, a direct connection mode, and a motor running mode, can be selected. ETC
In the mode, the first clutch 34 and the brake 37 are disengaged, and the second clutch 38 is engaged. At this time, the rotation speed and the torque of the ring gear 36 depend on the rotation speed and the torque of the engine 10 connected to the sun gear 31 and the running motor 20 connected to the planetary carrier 33, as is clear from the above-described relational expression. It is determined. Therefore, if the rotation speed of the traveling motor 20 is controlled while operating the engine 10 at a constant rotation speed and torque, the rotation speed of the ring gear 36 can be changed smoothly, and smooth acceleration of the vehicle is realized. be able to.
Since the operation state of the traveling motor 20 in the ETC mode is a regenerative operation, it is effective to use the ETC mode in a state where the charged amount of the battery 22 is low or in a cold state.

In the direct connection mode, the clutches 34 and 38 are engaged, and the brake 37 is disengaged. At this time, as is apparent from the above-mentioned relational expression, the planetary gear 30 rotates integrally, so that the power of the engine 10 is directly transmitted to the CVT 40. Therefore, during the running of the vehicle in the direct connection mode, the vehicle can be driven only by the power of the engine 10 (engine running mode).
At this time, since the operation state of the traveling motor 20 can be a regenerative operation, a part of the power of the engine 10 can be regenerated during this traveling mode. In addition, since the running motor 20 can be powered in conjunction with the transmission of the engine power, the vehicle can be run with the power of the engine 10 assisted (engine / motor running mode).

In the motor running mode, the first clutch 3
4, only the second clutch 38, the brake 37
Is disengaged. Therefore, the vehicle can be driven by the motor while the engine 10 is stopped. At this time, the traveling motor 20 is connected to the CVT 40. In the state where the second clutch 38 and the brake 37 are released, the rotation state of the ring gear 36 is not determined, and the rotation state of the planetary gear 30 is not determined, which is equivalent to the engine 10 being substantially disconnected.

Here, the situation immediately after switching from the N range or the P range to the above-described forward shift position will be described. In this situation, the vehicle that has been stopped because it has been in the N range or the P range starts running (starts). At the time of this start, the start in the ETC mode and the start in the motor traveling mode are used properly. Even when the vehicle starts in both modes, the engagement and disengagement states of the first and second clutches and brakes are as described in the above-described modes. The vehicle is started with 10 powers. At this time, since the traveling motor 20 can be charged by the regenerative operation, the start of the ETC mode is effective when the charged amount is low or when the vehicle is cold. In the motor running mode start, the vehicle is started by the motor while the engine 10 is stopped. After starting in this way,
The operation mode is changed to one of the above three types of operation modes at any time according to the state of the charged amount or the torque required for running the vehicle. The start of the ETC mode and the start of the motor drive mode are also used when starting the vehicle from a situation where the vehicle is stopped at the B / D running position. Also, E
Since the start in the TC mode is based on the assumption that the engine is operating, if the engine is stopped before the start, the start in the TC mode is performed after the engine is started by an engine start process described later.

When the shift lever is in the N range or the P range, a neutral mode or a charging or engine starting mode can be selected. In the neutral mode, all of the clutches 34 and 38 and the brake 37 are disengaged. Therefore, no power can be transmitted to the CVT 40, and at the same time, the engine 10 and the traveling motor 20 are stopped. charging,
In the engine start mode, only the brake 37 is engaged,
The clutches 34 and 38 are disengaged. Clutch 34, 3
8 is disengaged, power is not transmitted to the CVT 40, but the rotation state of the planetary gear 30 can be determined by engaging the brake 37. Therefore, it becomes possible to regenerate the power of the engine 10 by the traveling motor 20 or conversely crank the engine 10 by powering the traveling motor 20. It is effective to regenerate the engine power in a situation where the charged amount of the battery 22 is reduced. At the time of starting the engine, in addition to the starting by the power running of the traveling motor 20, the clutches 34 and 38 and the brake 37 as in the neutral mode described above.
May be disengaged, and the starter motor 14 may be powered to crank and start the engine 10. In this way, in the N / P range, the engine start by the traveling motor 20 and the engine start by the starter motor 14 can be executed, but which engine start is executed will be described later.

Since it is not necessary to use the belt 13 to start the engine by the powering of the traveling motor 20, the following advantages are obtained when adopted for starting the engine at a low temperature.

When the outside temperature and the temperature in the engine room are low, the belt 13 made of an elastic material such as rubber
It is harder than after warming or at high temperatures. If the belt 13 remains hardened, belt slip is likely to occur during engine cranking. Also, at low temperatures, the engine oil also has a high viscosity, so that the friction of each part of the engine sliding is not sufficiently reduced and the belt load during cranking may be large. Therefore, if the engine is started by the power running of the traveling motor 20 at a low temperature at which the belt hardening and the load increase are likely to occur, the engine can be started reliably without incurring the above-mentioned problems. If the engine is started by the power running of the starter motor 14 except when the temperature is low, the engine can be reliably started without causing the above-described problems.

When the shift lever is in the R range, a motor traveling mode and a friction traveling mode can be selected. In the motor drive mode, the first clutch 34
Only the second clutch 38 and the brake 37 are disengaged. At this time, the traveling motor 20 is set to CVT4
It is in a state of being connected to 0. In the friction running mode, the first clutch 34 is engaged and the second clutch 3
8 is disengaged, and the brake 37 is slip-engaged. This makes it possible to cause the vehicle to travel backward by using the power of the traveling motor 20 and the engine 10 or only by the power of the engine 10.

The hybrid vehicle of this embodiment travels by using these operation modes properly. The description will be made by taking the case of moving forward as an example. First, the operation of the engine 10 is stopped during a stop, including a temporary stop such as waiting for a traffic light. As described above, during this time, the auxiliary machine 12 is driven by powering the starter motor 14. When the driver steps on the accelerator pedal to perform an acceleration operation, the engine 10 starts operating based on an engine start process described later. And
By adjusting the regenerative power of the traveling motor 20 in the ETC mode, the engine 10 starts and accelerates by outputting while changing the rotational speed of the engine 10 smoothly. In some cases, the vehicle may be started using only the power of the traveling motor 20 in the motor traveling mode. When the vehicle starts in the motor running mode, the engine 10 is stopped at the time of starting, but the engine 10 is started appropriately by an engine start process described later.
Thereafter, the direct connection mode is selected when the driving state is sufficient for shifting the power of the engine 10 only by the CVT 40, and the ETC mode is selected when the shifting is required beyond the shifting range by the CVT 40. To run.

Next, an engine starting process for starting the engine 10 will be described. FIG. 4 is a flowchart showing the contents of the engine start process. The CPU of the control unit 60 repeatedly executes the engine start process together with other control processes. When this process starts,
First, the CPU determines whether there is a request to start the engine 10 (step S100). The request to start the engine 10 is issued by a control process (not shown) for performing traveling control by using each of the operation modes described above. For example, when the running control is performed in the motor running mode, when the running mode is switched from the motor running mode to the direct connection mode in which regenerative charging can be performed due to a predicted shortage of stored power,
It is necessary to start the engine 10. Further, in the engine running mode, it is necessary to start the engine 10 even when the mode is switched to a mode in which the engine is used together (direct connection mode) because a torque shortage is expected. Therefore,
In such a case, an engine start request is issued in the traveling control process. The same applies when the vehicle is traveling backward.

If it is determined in step S100 that there is no request to start the engine, this routine is temporarily terminated without performing any processing. On the other hand, if it is determined in step S100 that an engine start request has been made, the vehicle speed sensor 54 is scanned to read the vehicle speed v (step S110).

Subsequently, the read vehicle speed v is compared with a predetermined reference vehicle speed SPD1 (step S120).
According to the result, the engine start by the traveling motor 20 (step S130) or the engine start by the starter motor 14 (step S140) is executed.

Before starting the engine by the traveling motor 20 in step S130, the vehicle is traveling in the motor traveling mode at a vehicle speed v exceeding the reference vehicle speed SPD1. Accordingly, the clutch / brake engagement state shown in FIG. 3 is switched in preparation for starting the engine by the traveling motor 20.
In other words, the braking 37
Is disengaged and the second clutch 38 is gradually engaged while the first clutch 34 is in the engaged state, so that the second clutch 38 is engaged in the direct connection mode. Thereby, the planetary gear 30
, The rotation of the traveling motor 20 can be transmitted to the engine 10, so that while the engine 10 is cranked by the traveling motor 20, other control for starting the engine, specifically, fuel injection control or Execute ignition control and the like. After starting the engine 10 in step S130 including such a series of processes, this routine is temporarily ended.

When the engine is started in step S130, the vehicle is running at a relatively high speed exceeding the reference vehicle speed SPD1, as described above. For this reason, even if a shock occurs in the vehicle due to the clutch engagement and the transmission of the engine power started by the traveling motor 20, the occupant is less likely to feel uncomfortable due to the shock. Moreover,
Since the engine is started while gradually engaging the clutch as described above, the engine power can be smoothly transmitted, and the above-mentioned uncomfortable feeling can be further reduced.

It should be noted that the traveling motor 20
After the engine 10 is started, the direct connection mode, the ETC mode, or the motor driving mode is used properly as described above, depending on the subsequent driving conditions and the like.

On the other hand, in step S140 when the vehicle speed v is equal to or lower than the reference vehicle speed SPD1, while the engine 10 is cranked by the starter motor 14, various controls such as fuel injection control for starting the engine are executed.
Start 0. After starting the engine in this way, the present routine is temporarily ended.

Here, the engagement state of the clutch / brake at the time of starting the engine by the starter motor 14 in step S140 will be described. If it is determined in step S120 that the vehicle speed v is equal to or less than the reference vehicle speed SPD1, the vehicle is traveling at a low speed (motor traveling mode) or stopped (vehicle speed v = 0) at a vehicle speed v equal to or less than the reference vehicle speed SPD1. It is in. Further, even when the vehicle is stopped, the shift position may be a forward drive position of B / D and a stop position of N / P, and as shown in FIG.
The engagement state of the brake differs in the operation mode in each of these shift positions. Therefore, step S14
The engagement state of the clutch / brake when the engine is started by the starter motor 14 at 0 is as follows.

When the engine is started in step S140 and the vehicle is in the forward traveling position (motor traveling mode) and the vehicle is traveling at a low speed below the reference vehicle speed SPD1, the clutch / brake engagement state is in the motor traveling mode. Therefore, at this time, the cranking by the starter motor 14 is performed in a state where the CVT 40 and the engine 10 are separated from each other, so that the engine 10 can be started by the low torque starter motor 14 without any trouble. The power of the engine 10 started by the starter motor 14 is changed from the engagement state in the motor drive mode to the engagement state in the direct connection mode in which the second clutch 38 is engaged, so that the CVT 40 is transmitted through the planetary gear 30. Can be transmitted to As described above, when transmitting the power of the engine 10 to the CVT 40, the engine power at the time of starting is small because the start is performed by the low-torque starter motor 14, and the vehicle is running at low speed as described above. Since the engine 10 only needs to be operated at a low speed, the shock due to the transmission of the engine power can be reduced. Whether the vehicle is in the forward running position can be detected by a shift sensor (not shown) or the like. If the vehicle is traveling at low speed (0 ≠ vehicle speed v ≦ SPD1), it can be determined that the vehicle is in the forward position.

Even if the vehicle is stopped (vehicle speed v = 0) and the vehicle is stopped (vehicle speed v = 0) when the engine is started in step S140, the clutch / brake engagement state is the state of the motor travel mode. Because it is in
As described above, the engine 10 can be started without any trouble. In the case of this engine start, the vehicle is prepared for the subsequent vehicle start. Therefore, in order to start the vehicle with the engine 10 started by the starter motor 14, the first clutch 34 is disengaged and the second clutch is engaged while the brake 37 is disengaged, and the engagement in the motor drive mode is performed. ET from state
The C-mode is engaged. As a result, the driving mode is set to the ETC mode start described above, and the engine 1 after the start is started.
The power of 0 can be transmitted to the CVT 40 via the planetary gear 30 to start the stopped vehicle. Even when such engine power is transmitted, the shock due to engine power transmission can be reduced as described above. In the hybrid vehicle according to the present embodiment, the vehicle can be started by starting in the motor running mode instead of starting in the ETC mode as described above. However, the start of the motor running mode does not involve the start of the engine, and is executed by another control.

When the engine is in the stop position at the time of starting the engine in step S140 and the vehicle is stopped (vehicle speed v = 0), the clutch / brake engagement state is the engagement corresponding to each operation mode of the stop position (see FIG. 3). In state. Therefore, even in the case of the cranking by the starter motor 14 at this time, since the CVT 40 and the engine 10 are separated from each other, the engine 10 can be started without any trouble. If the engine 10 started in this way is to charge the battery or to start the vehicle, the operation may be continued until the charging is sufficient or the warm-up is completed, and it is not necessary to transmit the engine power to the CVT 40. Therefore, after the engine is started by the starter motor 14, the engagement state of the clutch / brake corresponding to each operation mode of the stop position (see FIG. 3) may be maintained.

In this case, if the engine is started in the neutral mode shown in FIG. 3, since the brake 37 is disengaged and the engine 10 is also disconnected from the traveling motor 20, cranking by the starter motor 14 is performed. The engine 10 can be started quickly. If the engine is started in the charging and engine start mode, the traveling motor 20 rotates regeneratively even during engine cranking due to the engagement of the brake 37. Therefore, the cranking by the starter motor 14 is in a state where the rotation fluctuation is suppressed by the regenerative rotation of the traveling motor 20 and the cranking speed is stabilized. Therefore, the engine start timing can be stabilized. In addition, the cranking speed is reduced by an amount corresponding to the regenerative operation of the traveling motor 20. Therefore, in addition to stabilizing the engine start timing, the start timing can be delayed.

In addition, according to the present engine start routine, the engine is started when the vehicle is shifted to the forward traveling position and started when the vehicle is stopped in the N / P range.
The engine starts in step S140. Even in this case, before the shift change, the CVT 40 and the engine 1
Since 0 is an engaged state of the disengaged clutch / brake, the engine 10 can be first started by the starter motor 14 in this engaged state. Then, after the engine is started, the ETC is changed from the engaged state of the stop position.
If the mode is engaged, the situation becomes the same as the above-described ETC mode start, and the power of the engine 10 can be transmitted to the CVT 40 via the planetary gear 30 to start the stopped vehicle. Even in such an engine start, the engine 10 can be started without any trouble as described above, and the shock due to the transmission of the engine power can be reduced.

As described above, in the hybrid vehicle of the present embodiment, even when the start request of the engine 10 is issued, if the vehicle speed v at that time exceeds the reference vehicle speed SPD1, the engine by the traveling motor 20 is used. A start is performed (step S130). In this manner, the power transmission of the engine 10 started by the traveling motor 20 is performed, and even if a shock is generated in the vehicle due to the power transmission, the shock is generated in a vehicle traveling at a relatively high speed exceeding the reference vehicle speed SPD1. Not just. Therefore, it is possible to make it difficult for the vehicle occupant to feel uncomfortable feeling due to the shock accompanying the transmission of the engine power. In addition, when the engine is started by the traveling motor 20, the engine is started while gradually engaging the clutch for transmitting the engine power, so that the engine power can be transmitted smoothly and the above-mentioned uncomfortable feeling can be further reduced.

Even when a request to start the engine 10 is issued, the engine is started by the starter motor 14 only when the vehicle speed v at that time is equal to or lower than the reference vehicle speed SPD1 (step S140). Motor 1
4 can be performed less frequently. For this reason, the starter motor 14 can have a simple structure and a small size.

Further, when the engine is started by the starter motor 14, the cranking by the starter motor 14 is performed in a state where the CVT 40 and the engine 10 are separated. Therefore, the engine 10 can be started by the small and low-torque starter motor 14 without any trouble. Then, the engine 1 is first driven by the starter motor 14.
0 is started and the engine power transmission is
, The shock caused by the transmission of the engine power can be reduced.

Next, a modified example will be described. This modification is characterized in that the process for starting the engine by the traveling motor 20 is limitedly incorporated into the engine start routine even when the vehicle speed v is equal to or lower than the reference vehicle speed SPD1. FIG. 5 is a flowchart showing a main part of an engine start process according to a modification.

As shown in the figure, in this modification, a negative determination (0 ≦ vehicle speed v ≦ SPD) in step S120 is performed.
Subsequent to 1), it is determined whether the shift position is in the P range and the outside air temperature at that time is equal to or lower than the predetermined temperature T0 (step S135). The shift range can be detected by the shift sensor, and the outside temperature can be detected by the outside temperature sensor 55. The predetermined temperature T0 may be a temperature at which the belt 13 is expected to be hardened or the viscosity of the engine oil is increased, for example, about 0 ° C. If the belt 13 and the engine oil are of a cold district specification, the predetermined temperature T0 can be set to a temperature of 0 ° C. or lower.

If it is determined in step S135 that the shift position is in the P range and the outside air temperature is equal to or lower than the predetermined temperature T0, the process proceeds to step S13.
Then, the engine 10 is started by the traveling motor 20. In this case, the engine is started by the traveling motor 20 in the P range. Therefore, the clutch / brake that can power the engine 10 by the traveling motor 20 is set to the engaged state in the charging and engine start mode, and then the engine 1 is driven by the traveling motor 20.
Other control for starting the engine is executed while cranking 0. Thus, the engine 10 can be started by the traveling motor 20. That is, the vehicle speed v
Even if the vehicle speed is equal to or lower than the reference vehicle speed SPD1, in a limited situation where the shift position is in the P range and the outside air temperature is equal to or lower than the predetermined temperature T0, the engine can be started not by the starter motor 14 but by the traveling motor 20. it can.

According to this modification, the starter motor 14
The engine start by the starter motor 14 should be started under the condition that the belt 13 for the engine cranking is hardened or the engine oil becomes highly viscous and the belt load at the time of the cranking is expected to increase. You can not do it. For this reason, since the belt 13 is not used while being hardened or under a high load, careless damage to the belt can be avoided. In such a situation, the engine 10 is started by the traveling motor 20 connected to the engine 10 via the planetary gear 30, so that the engine can be started reliably.

Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it goes without saying that various configurations can be adopted without departing from the spirit of the present invention. For example, the above-described control processing may be realized by software or by hardware. The starter motor 14 is not limited to a synchronous motor, and various AC motors and DC motors can be applied.

In the above embodiment, the reference vehicle speed SP
Although D1 is described as being fixed, the reference vehicle speed S depends on the amount of battery charge at the time of engine start request.
PD1 can also be set. For example, in a case where the amount of power storage is so small that cranking by the traveling motor 20 is impossible, the reference vehicle speed SPD1 is increased. This allows the starter motor 14 that consumes less power to start the engine. In addition, the set reference vehicle speed SPD1 and the frequency at which the start of the engine by the starter motor 14 is executed are stored and learned, and the reference vehicle speed SPD1 is reset so that the frequency decreases as the start of the engine by the starter motor 14 increases. You can also.

Further, the above-described engine start processing can be applied to the traveling motor 20 described in the present embodiment. In addition to a motor directly connected to a drive shaft and directly driving the drive shaft, an electric power for distributing engine output can be used. The present invention is also applicable to a motor that does not directly drive a drive shaft, such as a clutch motor in a distribution hybrid vehicle and a generator in a mechanical distribution hybrid vehicle.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a power system of a hybrid vehicle as an embodiment.

FIG. 2 is a circuit diagram of an inverter.

FIG. 3 is an explanatory diagram showing engagement states of clutches 34 and 38 and a brake 37 in each operation mode.

FIG. 4 is a flowchart showing the contents of an engine start process for starting the engine 10.

FIG. 5 is a flowchart showing a main part of an engine start process according to a modified example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Engine 11 ... Crankshaft 12 ... Auxiliary equipment 13 ... Belt 14 ... Starter motor 15 ... One-way clutch 16, 21 ... Inverter 17 ... Rotation speed sensor 20 ... Running motor 22 ... Battery 30 ... Planetary gear 31 ... Sun gear 32a, 32b ... Pinion gear 33 Planetary carrier 34 First clutch 35 Rotating plate 36 Ring gear 37 Brake 38 Second clutch 39 Rotating plate 40 Continuously variable transmission (CVT) 41, 42 Pulley 43 Belt 54 Vehicle speed sensor 55 ... Outside air temperature sensor 60 ... Control unit

Continued on the front page (72) Inventor Takanori Moriya 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3G093 AA06 AA07 AA16 BA02 CA01 DB01 DB05 DB09 DB11 DB12 EB00 FA11 5H115 PA01 PG04 PI16 PO17 PU10 PU24 PU28 PV09 PV23 QA01 QH03 QH04 QI04 QI07 QN03 RB08 RB22 RE01 SE04 SE05 TB01 TO05

Claims (3)

[Claims] 1. An engine as a power source of a moving body, a starting motor for starting the engine, an electric motor used as a power source other than the engine and capable of starting the engine, and starting the engine An engine start device comprising: a start control unit configured to perform an engine start by the electric motor and an engine start by the start electric motor in accordance with a moving state of the moving body. An engine starting device comprising: means for prioritizing execution of the engine by the starting motor when the situation is lower than a predetermined situation. 2. The engine is started by using a starting motor for starting an engine as a power source of a moving body and an electric motor used as a power source other than the engine and capable of starting the engine. Detecting a moving state of the moving body; and, if the detected moving state is lower than a predetermined state, the engine starting method using the electric motor and the engine starting using the starting electric motor. Prioritizing execution of the engine by the starting motor. 3. An engine and an electric motor are provided as power sources,
A hybrid vehicle having the electric motor as a motor capable of starting the engine, comprising: a starting motor for starting the engine; a unit for detecting a moving state of the vehicle; and the detected moving state being lower than a predetermined state. In a case, the hybrid vehicle includes means for prioritizing execution of the engine by the starting motor among the engine starting by the electric motor and the engine starting by the starting motor.