JP3373822B2 - Engine start determination device and engine start control device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely decide engine start, without impairing accelerating performance, even if it is mounted in a so-called hybrid car equipped with a single motor and a single engine. SOLUTION: A start deciding device is applied to a drive device in which a motor 34 directly coupled with an engine 32 is formed so as to start the engine 32, where the driving force of the motor 34 is changed in the decremental direction, after the fuel supply to the engine 32 and ignition therein are commenced. If the engine revolving speed rises regardless of this change, decision is made that the engine 32 has attained the completely combusted condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine start determination device in which a motor connected to an engine is applied to a drive device configured to start the engine, and more particularly to this motor. The present invention relates to an engine start determination device suitable for application when a vehicle has a function of running a vehicle and an engine start control device using the same.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a so-called hybrid vehicle or the like in which an internal combustion engine and an electric motor are mounted and which can output driving power from the electric motor, in which the internal combustion engine is started by the electric motor.

An engine start control device mounted on a hybrid vehicle of this type is disclosed in, for example, Japanese Patent Laid-Open No. 11-1530.
75, and the outline of the portion related to the present invention in the contents will be described below with reference to FIG.

This hybrid vehicle 1 is equipped with an engine 2 that outputs power using gasoline as fuel, and first and second motor generators MG1 and MG2. Specifically, the crankshaft of the engine 2 is a power split. Mechanism 4
Are connected to the first motor generator MG1 and the second motor generator MG2 via the.

The power split mechanism 4 has a planetary gear structure including a carrier that holds a planetary gear, a sun gear, and a ring gear. The crankshaft of the engine 2 is connected to the carrier, and the rotor of the first motor generator MG1 is the sun. The rotor of the second motor generator MG2 is connected to a gear, and is connected to a ring gear (not shown).

First and second motor generators MG1,
The MG2 is controlled by the controller 8 via the inverter 6, and the inverter 6 is connected to the battery 10 as a power supply source.

A speed reducer 14 is arranged on a connecting shaft 12 connecting the first motor generator MG1 and the power split mechanism 4, and the rotational power of the connecting shaft 12 is applied to the wheels 16, 16 with a predetermined reduction ratio. Transmitted.

The first motor generator MG1 is driven mainly by electricity supplied from the battery 10 as an energy source, and transmits the rotational power to the wheels. Further, during braking, it also acts as a generator to regenerate the braking energy of the wheels, and the regenerative energy charges the battery 10 via the inverter 6.

The second motor generator MG2 mainly functions as a generator, is driven by receiving a part of the rotational power of the engine 2, and charges the battery 10 via the inverter 6. Further, when a predetermined driving force is required for the first motor generator MG1 at the time of sudden acceleration or the like, the electricity generated by the second motor generator MG2 is directly transmitted via the inverter 6 to the first motor generator M1.
Supplied to G1.

The engine 2 outputs rotary power using gasoline as fuel, and this rotary power is split by the power split mechanism 4, one of which is transmitted to the wheels through the speed reducer 14 and the other of which is the second motor generator. Used for power generation of MG2. The engine 2 is controlled by the controller 8 and does not always operate like a conventional engine vehicle, and is stopped when a predetermined stop condition is satisfied even while traveling, and a predetermined start condition is set. If it is established, it will be started. The stop / start conditions are determined by the driving power required by the vehicle (determined by the driver's accelerator depression, etc.), the battery voltage, the engine required power obtained from the operation of the air conditioner, etc. The engine 2 is started when a predetermined threshold value as a condition is exceeded, and is stopped when a predetermined threshold value as a stop condition is exceeded.

Since the hybrid vehicle 1 functions as described above, (1) a mode in which only the power of the engine 2 is mechanically transmitted to the wheels for traveling, (2) the power of the engine 2 drives the second motor generator MG2. Is generated and the vehicle is driven only by the first motor-generator MG1, and (3) the mode in which the engine 2 is stopped and the vehicle is driven by the first motor-generator MG1 alone as an electric vehicle. You can switch efficiently. Therefore, the fuel efficiency is significantly improved and the emission is reduced as compared with the conventional gasoline engine vehicle, and the restriction of the following distance and the trouble of external charging, which are found in the electric vehicle, are eliminated.

In such a hybrid vehicle 1, generally, when the engine is started, an operation for switching to a traveling control system different from that before is often performed. If this switching is not performed exactly in accordance with the complete explosion / starting of the engine, smooth vehicle drive control is impaired to that extent, and in particular, despite the fact that the engine has not completed complete explosion / starting for some reason, If the next control is performed assuming that the explosion has been completed / started, it has a great influence on the running. Therefore, it is important to accurately determine the complete explosion / start of the engine.

The conventional complete explosion / starting determination when the engine 2 is started up when the starting condition is satisfied will be described below.

The starting control device for the engine 2 is mainly composed of the controller 8. First motor generator M
The second motor-generator MG2 is controlled so that the crankshaft of the engine 2 is stopped during traveling only with G1, that is, the first motor-generator M.
The rotation of G1 is transmitted (or absorbed) only to the second motor generator MG2 via the power split mechanism 4.

When the starting condition of the engine 2 is satisfied in this state, the controller 8 controls the second motor generator MG2 to drive the engine 2 via the power split mechanism 4. Specifically, when the second motor generator MG2 drives the engine 2, the power split mechanism 4
The first motor generator MG via the (planetary gear structure)
Although the driving force is also transmitted to the 1 side, the first motor generator MG1 is controlled so as to overcome this driving force to drive the hybrid vehicle 1 at a predetermined speed, and the second motor generator MG2 directly drives the engine 2. It intentionally creates a driving state.

The engine 2 is started by a series of starting operations in which the rotation speed of the engine 2 is gradually increased by the second motor-generator MG2 and fuel supply and ignition are started when a predetermined ignition rotation speed is reached. Will be realized. Here, the engine 2 is used to determine the start of the engine 2.
2) so that the rotation speed of is maintained at a predetermined target rotation speed.
Controls motor generator MG2. This control is achieved by PI-controlling the second motor generator MG2 by the controller 8 to which the rotation speed of the engine 2 is constantly input. Specifically, the difference between the rotation speed of the engine 2 and the target rotation speed is determined. The calculation is performed and the target torque value required for the second motor generator MG2 is calculated accordingly.

When the engine 2 is maintained at the target rotation speed in this way, the engine 2 becomes a "load" in the state where the complete explosion has not occurred, so that the second motor generator MG2 is required to operate as described above. The target torque value is always positive.

On the other hand, when the engine 2 is completely detonated, that is, when the engine 2 is operated independently by explosion / combustion, the controller 8
The target torque value calculated by is less than or equal to zero. Therefore, the second speed for maintaining the rotation speed of the engine 2 constant
If the target torque value of the motor generator MG2 changes from plus to minus, it can be determined that the engine 2 has completely exploded / started there.

[0019]

In the hybrid vehicle 1 configured as described above, the complete explosion of the engine 2 is determined under the control of maintaining the rotation speed of the engine 2 constant. In a hybrid vehicle including one engine and one motor generator, the above starting control cannot be performed for the following reason.

In this hybrid vehicle, one motor generator is connected to the crankshaft of the engine, and (1) a mode in which only the rotational power of the engine is transmitted to the wheels for traveling, (2) the engine is in the idling state ( It is possible to select three modes: a mode of traveling only with the rotational power of the motor in a rotation state without combustion) and a mode of traveling with the rotational power of the engine and the motor (3).

When the engine starting condition is satisfied in the mode (2) in which the vehicle is driven only by the rotational power of the motor-generator, fuel is supplied to the engine to start the engine and determine the complete explosion. Must be,
The rotation speed of the motor generator is required for the vehicle speed (determined by the degree of accelerator depression by the driver)
Since it is controlled over time based on the above, it is impossible to control the engine rotation speed to be constant in the first place. That is, in order to keep the engine rotation speed constant, this means maintaining the motor generator rotation speed constant, and as a result, the "vehicle speed" must be kept constant, which is irrational.

After all, if two motor generators such as the hybrid vehicle shown in the conventional example are provided, one vehicle can be in charge of running and the other can be in charge of starting the engine. The load condition of the motor generator can be observed by the feedback control that keeps the rotation speed constant. However, when the vehicle travels and the engine is started by one motor generator, the feedback control itself cannot be performed. was there.

Further, in a vehicle having two motor generators, although it is certainly possible to determine the start by the conventional method, basically the engine speed is kept constant until the start is determined. Since there is a request to maintain, even if there is a sudden acceleration request, it will dare to suppress the rise of the engine speed for the start judgment.
There is a problem that the acceleration response is sacrificed.

The present invention has been made in view of the above problems, and can be applied to a hybrid vehicle or the like provided with an engine and only one motor generator, and sacrifices the smooth startup of the engine at an early stage. It is an object of the present invention to provide an engine start determination device that enables complete explosion / start determination of an engine without doing so and an engine start control device using the same.

[0025]

SUMMARY OF THE INVENTION The present invention is a start determination device for an engine, which is applied to a drive device configured to start the engine by a motor directly connected to the engine. Means for starting the starting operation of the engine, and a driving force changing means for changing the driving force applied to the engine by the motor from a predetermined time point to a reducing direction after the starting operation of the engine is started. Provided that the change in the direction of reduction of the driving force is followed by the engine rotation speed, it is determined that the engine has not completely exploded,
The object is achieved by determining that the engine has completed the complete explosion / starting when the engine does not follow.

The present invention focuses on the relationship between the engine rotation speed and the driving force of the motor for increasing the engine rotation speed. In this start-up determination device, after the engine start operation (fuel injection and ignition at a predetermined rotation speed) is started, it is given to the engine from a predetermined time point (a time point when normal complete explosion is considered to be completed). Change the driving force of the motor to "reduction direction".

If, for some reason, the engine has not reached the complete explosion state at this point, the engine rotational speed also shifts / follows the reduction direction in accordance with the change in the reduction direction of the driving force.

However, when the engine has already reached the complete explosion state at this time, the engine rotation speed does not follow the driving force of the motor even though the driving force of the motor is changed to the reducing direction. Continues to rotate as it is. Therefore, by observing the engine rotation speed when the driving force of the motor is changed in the reducing direction, it is possible to determine whether or not the engine has reached a complete explosion / starting.

This change in the "reduction direction" may be, for example, a change to reduce the increase in the driving force that has been increased, or to stop the increase. It may be changed (Claim 2), or the driving force may be actually lowered (Claim 3). The stronger the degree of reduction, the sooner and more clearly the complete combustion state of the engine can be determined. In this case, however, if the complete explosion has not been completed, the engine speed will decrease by that much. Therefore, there is a fear that it will take longer to complete the final explosion. Therefore, the degree of change in the reduction direction may be appropriately set according to the nature of control performed after completion of engine start.

The change of the "reduction direction" of the driving force is changed to the direction of decreasing the current value of the motor which has been given so far (when the increase rate is reduced, the increase is stopped, or the increase is stopped). Including) to include the concept.

According to this start-up determination device, in many cases, the "predetermined time point" is set so that it is determined that the complete explosion / startup is completed, so that the engine rotation speed can be continuously increased without being stagnant. Therefore, the acceleration response is not impaired. This advantage is a great advantage considering that most of the reason that the engine that was in the stopped state is started is that the driver depresses the accelerator pedal.

Further, this start determination can be applied to a one-motor type vehicle or a two-motor type vehicle. Furthermore, it can be applied while the vehicle is stopped or running.

If the engine is judged to be in the non-complete explosion state by this start judgment, the starting control of the engine may be re-executed after increasing the driving force of the motor.

In this way, even if the engine cannot be easily started and it takes a long time to start, the motor driving force is once restored (increased) and then the complete explosion determination is performed again. As a result, the start of the engine can be further promoted, and it is possible to prevent the driving force of the motor from being excessively reduced and affecting the traveling of the vehicle.

It should be noted that the increase in the driving force of the motor may be restored to the driving force currently required by the vehicle so as to exhibit reliable running performance.

Further, in the above invention, if it is determined that the engine does not reach the complete explosion / starting state as a result of the re-execution means performing the engine start determination a predetermined number of times, the engine start itself is stopped. You may

By doing so, it is possible to prevent unnecessary fuel supply or power consumption and improve fuel efficiency when the engine cannot be started.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a hybrid vehicle 30 to which an engine start determining device according to a first embodiment of the present invention is applied.
Shows the configuration of.

This hybrid vehicle 30 has an engine 3
The motor 34 directly connected to the motor 2 is provided with a drive device configured to start the engine 32. More specifically, the rotor of the motor 34 is directly connected to the crankshaft of the engine 32. The rotational power of the motor 34 is configured to be transmitted to the transmission 38 via the torque converter 36.

The engine 32 explodes and burns by the supply of gasoline fuel to generate rotational power, and this rotational power is mainly used for running the hybrid vehicle 30, but depending on the situation, a part of the motor 34 may be used. It is used to drive the rotor.

A battery 42 is connected to the motor 34 via an inverter 40, and mainly functions as an electric motor, and rotational power is generated by using an AC voltage converted from the battery 42 via the inverter 40. This rotational power is mainly transmitted to the transmission 38 via the torque converter 36 and is used for traveling of the vehicle. However, as described later, when the engine 32 is not supplied with fuel, the engine 32 runs idle. It is also used to let people do it.

When braking energy is generated in the vehicle by a brake or the like, or when the voltage of the battery 42 is below a predetermined value, the motor 34 functions as a generator and the braking energy or the engine 32 drives the rotor. Output AC voltage. This AC voltage is applied to the inverter 40
Is converted into a DC voltage and the battery 42 is charged.

The engine 32, the motor 34, the transmission 38 and the like are controlled by a control signal from an electronic control unit ECU 44, and the ECU 44 has rotational speed (rotation speed) information from the engine 32, voltage information of the battery 42 and an accelerator. Accelerator sensor 4 provided at 46
The accelerator depression amount information and the like from 8 are input.

The hybrid vehicle 30 is constructed as described above, and (1) a mode in which the engine 32 alone is used for driving, (2) a mode in which the motor 34 alone is used as an electric vehicle, and (3) the engine 32 and the motor 34. The mode in which the vehicle is driven by the rotational power of
It is possible to drive with a minimum consumption of gasoline supplied to the vehicle. Further, in the mode (2) in which the electric motor vehicle is driven only by the motor 34, the crankshaft directly connected to the rotor is driven by the motor 34, and the engine 32 becomes idling (rotating without combustion). It rotates at the rotation speed.

Next, the start control accompanied by the start determination control of the engine 32 applied to the hybrid vehicle 30 will be described in detail.

This start control device mainly consists of the ECU 44.
The engine 32 is started according to the processing flowchart shown in FIG.

When the starting condition of the engine 32 is satisfied from various information input to the ECU 44, the engine starting process shown in FIG. 2 is started. First, at step 100, it is judged whether or not the vehicle speed is zero, that is, the vehicle speed is zero. If not, the process proceeds to step 102. If this determination is positive, that is, the vehicle speed is zero, the routine proceeds to step 104. Where step 1
The engine starting process on the 02 side (or later) shows the starting process of the engine 32 when the hybrid vehicle 30 is driven by the motor 34, and is a part directly related to the present invention. Further, the step 104 side (or later) is the engine 32 when the hybrid vehicle 30 is stopped.
The starting process is performed, and the same process as that of the conventional example is performed. First, the starting process on the step 102 side will be described.

In step 102, the engine 32
Is in the idling state, fuel injection and ignition by the plug are executed for this engine 32. Next, after continuing the fuel injection and ignition for a predetermined time by passing through step 106, the process proceeds to step 108, and the torque of the motor is reduced. It should be noted that this is performed by lowering the voltage value supplied to the motor 34 via the inverter 40 or the like.

Next, in step 110, the engine 32
It is determined whether the rotation speed of the engine 3 has decreased, and if this determination is negative, that is, the torque of the motor 34 is decreased, the engine 3
When the rotation speed of 2 does not decrease, it is determined that the engine 32 has completely exploded, and the routine proceeds to step 112, where the complete explosion determination flag is turned on. This completes the start of the engine 32.

On the other hand, the determination in step 110 is positive,
That is, the engine 32 follows the decrease in the torque of the motor 34.
If the rotation speed of the engine has decreased, it is determined that the engine 32 has not completed the explosion yet, and the routine proceeds to step 114. In step 114, the torque of the motor 34 is returned to the torque value required at present, and in step 116, the number of times of starting failure is counted (+1). Next, in step 118, it is determined whether or not the startup failure counter (startup failure frequency) is greater than or equal to a predetermined value. If the result of the determination is negative, that is, the failure frequency is less than the predetermined value, the process returns to step 102 and engine startup determination is re-executed. . On the other hand, if the determination in step 118 is positive, that is, if the number of times of starting failures is equal to or greater than the predetermined value, step 120
Then, the start of the engine 32 itself is stopped.

Next, the starting process on the step 104 side will be described.

In step 104, the hybrid vehicle 30 is stopped, and the motor 34 and the engine 3 are stopped.
Since both rotations of 2 are stopped, the motor 34 starts driving the engine 32. The motor 34 is controlled so that the rotation speed gradually increases with a predetermined determination rotation speed as a target value. In this case, the clutch (not shown) in the transmission 38 is released,
It is performed in a state where the rotational power of the motor 34 is not transmitted to the wheels.

Thereafter, in step 130, when the engine 32 reaches the ignition rotation speed, fuel injection and ignition by the plug are executed (starting of the starting operation). The ignition rotation speed is set lower than the determination rotation speed, that is, fuel supply or the like is started while the engine is being pulled up to the determination rotation speed by the motor 34.

Next, at step 132, the ECU 44
It is determined whether the required torque value required for the motor 34 calculated by the above is negative, and if the determination is positive, that is, the target torque value is negative, it is determined that the engine 32 has completely exploded and the step 1
In 12, the complete explosion determination flag is turned on. On the other hand, if the determination in step 132 is negative, that is, if the target torque value is positive, it is determined that the engine 32 is in the non-complete explosion state, and the routine proceeds to step 134, where it is determined from the start of raising the engine 32 rotation speed in step 104. Determine if time has passed. If this determination is negative, that is, if it is within the predetermined time, the process returns to step 130, and fuel is supplied (step 130).
Then, the complete explosion determination (step 132) is performed again. On the other hand, if the determination in step 134 is positive, that is, if the engine does not complete explosion after the elapse of a predetermined time, the start itself of the engine 32 is stopped in step 136. The predetermined time is set to about 10 seconds in this embodiment.

According to the start control device for the engine 32, even when the hybrid vehicle 30 is traveling by the motor 34, the complete explosion determination of the engine 32 can be reliably performed and the engine 32 can be started. Further, even when the vehicle is traveling, the complete explosion of the engine 32 can be determined only by controlling the drive torque of the motor 34.
The traveling of the hybrid vehicle 30 is not significantly affected. That is, if the complete explosion can be determined in the first determination step, the increase in the engine rotation speed is not suppressed at all for the determination. Therefore, it is possible to start the engine 32 while maintaining high acceleration response. it can.

Further, when the complete explosion of the engine 32 is judged, the torque of the motor 34 is changed in the decreasing direction. Therefore, if the rotation speed of the engine 32 is increased or maintained, it means that the engine is operating independently. Is clear, and the complete explosion can be reliably determined. Moreover, although the torque of the motor 34 is reduced to determine the complete explosion, the engine 32
If is not a complete explosion, the torque of the motor 34 is once returned (increased), and the start determination is re-executed. Therefore, a large drop in the torque of the motor 34 does not occur.
It is possible to drive the vehicle stably. In the present embodiment, the torque converter 36 is arranged between the motor 34 and the transmission 38, so that the above torque fluctuation is particularly absorbed.

If it cannot be determined that the engine 32 has completely exploded even after the engine start determination has been performed a predetermined number of times,
Since the starting of the engine 32 itself is stopped, it is possible to prevent unnecessary fuel consumption and power consumption of the battery 42, which contributes to improvement of fuel consumption.

Incidentally, in the first embodiment described above, FIG.
In the step 108 shown in FIG. 5, the torque of the motor 34 is reduced to perform the complete explosion determination, but the present invention is not limited to this. For example, in step 108, the torque increase of the motor is stopped and kept constant, Nevertheless, if the rotation speed of the engine 32 increases in step 110, it may be determined that the complete explosion has occurred. In short, from step 108 (predetermined time point), the driving force that the motor 34 has given to the engine 32 up to then is changed to the “reduction direction”, and the engine rotation speed nevertheless follows the change. If it rises without a hit, it can be judged as a complete explosion.

When the degree of reduction is moderated in this way, torque fluctuation (pulsation) of the motor 34 is further prevented, so that the engine 32 can be reliably started while maintaining more stable running.

As a method of changing the driving force in the decreasing direction, for example, the current value of the motor 34, which has an increasing tendency, is controlled so as to reduce the increasing rate.

Further, in the first embodiment, the engine start control is different between when the motor is running and when the vehicle is stopped, but the present invention is not limited to this, and the torque of the motor can be controlled even when the vehicle is stopped. The complete explosion determination of the engine may be performed in a state where the engine is lowered or kept constant (the same state as when the motor is running).

In the present embodiment, the case where the engine start determination device is applied to a one-motor type hybrid vehicle has been shown, but the present invention is not limited to this, and the engine and the engine start only The present invention can also be applied to an engine vehicle equipped with the motor (motor capable of controlling driving force), and also to a two-motor type hybrid vehicle as described with reference to FIG.

[0064]

According to the present invention, it is possible to reliably determine whether or not the engine has started without impairing the acceleration performance, and in particular, including a hybrid vehicle having one engine and one motor, In various types of vehicles, it is possible to reliably determine the start of the engine regardless of whether the vehicle is stopped or running.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a hybrid vehicle to which a start determination device according to a first embodiment of the present invention is applied.

FIG. 2 is a flowchart showing engine starting control by the starting control device.

FIG. 3 is a block diagram showing a configuration of a hybrid vehicle to which a conventional engine start control device is applied.

[Explanation of symbols]

30 ... Hybrid vehicle 32 ... Engine 34 ... Motor 36 ... Torque converter 38 ... Transmission 40 ... Inverter 42 ... Battery 44 ... ECU

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI B60K 6/04 553 B60K 6/04 553 730 730 B60L 11/14 B60L 11/14 F02N 11/04 F02N 11/04 D 11/08 11/08 G (72) Inventor Takashi Suzuki 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Daifumi Okada 1 Daihatsu Town, Ikeda City, Osaka Prefecture Daihatsu Industry Co., Ltd. ( 56) References JP-A 2000-186654 (JP, A) JP-A 10-331749 (JP, A) JP-A 9-296771 (JP, A) JP-A 59-116032 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60K 6/02-6/04 B60L 11/02-11/14 F02D 29/02-29/06 F02D 45/00 F02N 11/04-11/08

Claims (5)

(57) [Claims] 1. A start determination device for the engine, which is applied to a drive device configured to start the engine by a motor directly connected to the engine, comprising means for starting a starting operation of the engine. A driving force changing unit that changes the driving force that the motor has given to the engine from a predetermined time point to a reducing direction after starting the engine starting operation, the driving force reducing direction When the engine rotation speed follows the change of No., it is determined that the engine has not completed explosion, and when it does not follow, it is determined that the engine has completed explosion / starting. Judgment device. 2. The driving force changing means according to claim 1, after the start operation of the engine is started, the increase of the driving force which the motor has given to the engine until a predetermined time point is stopped. An engine start determination device characterized by being a thing. 3. The driving force changing means according to claim 1, wherein the driving force changing means reduces the driving force applied to the engine by the motor from a predetermined time point after starting the engine starting operation. An engine start determination device characterized by being present. 4. The engine start determination device according to claim 1, further comprising increasing the driving force of the motor when it is determined that the engine has not completely exploded. After that, the engine start determination device is provided with a re-execution unit that re-executes the complete explosion / start-up determination. 5. The engine start determination device according to claim 4 is applied, and even if the re-execution means executes the engine complete explosion / start determination a predetermined number of times, it is possible to confirm the complete explosion / start of the engine. If not, the engine start control device stops the engine start itself.