JP2004270512A - Hybrid vehicle controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a throttle opening according to the presence or absence of automatic traveling during motor traveling accompanied by a fuel cut and effectively improve both fuel consumption and a response. <P>SOLUTION: A hybrid vehicle includes an driving motor 12 connected to an engine 11 and a driving wheel 10, and a setting switch 47 of an automatic speed controller that automatically maintains a constant vehicle speed and a distance between vehicles. During the motor traveling accompanied by a fuel cut, a crankshaft of the engine 11 directly connected to the motor 12 idles away to cause pumping loss and so on. Thus, if the vehicle is in the automatic traveling during the motor traveling, a throttle 23 is opened to reduce the pumping loss and improve the fuel consumption, and if it is not in automatic traveling, the throttle 23 is closed to improve the response. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for a hybrid vehicle that uses both an engine and a motor as a vehicle drive source.
[0002]
[Prior art]
In a hybrid vehicle that uses both an engine and a motor as a vehicle propulsion source, the throttle loss is increased by stopping the fuel supply to the engine, that is, while the vehicle is running with a fuel cut, by increasing the throttle opening. Loss due to the throttle) is reduced, and the fuel efficiency can be improved. For example, in Patent Literature 1, during a vehicle deceleration operation with a fuel cut, the throttle opening is fully opened to reduce pump loss.
[0003]
[Patent Document 1]
JP 2002-166754 A
[Problems to be solved by the invention]
During the running of the motor, which stops the fuel supply to the engine (fuel cut) and rotates the drive wheels while idling the engine's crankshaft, the drive wheels are mainly driven by the engine due to an acceleration request such as depressing the accelerator. When the engine shifts to driving, the negative pressure downstream of the throttle is adjusted so that the engine torque temporarily does not greatly increase immediately after the start of fuel injection and gives unexpected rushing feeling to the occupants of the vehicle. Needs to be sufficiently large so that the amount of intake air to the cylinder is sufficiently small before supplying and igniting fuel.
[0005]
However, due to the volume of the intake passage downstream of the throttle, etc., it takes some time from the opening of the throttle to the closing to the development of the negative pressure, so if the throttle is fully opened during motor running, During the transition period to the engine running, fuel supply and ignition cannot be performed until the negative pressure is sufficiently developed, and there is a concern that responsiveness to acceleration requests and the like may be reduced.
[0006]
By the way, in recent years, some vehicles equipped with an automatic speed control device (ACC; adaptive cruise control) for performing automatic traveling for automatically keeping at least one of the traveling speed and the inter-vehicle distance of the vehicle constant have been put to practical use. ing. During such automatic running, it is unlikely that rapid acceleration will be required, and the response to an acceleration request or the like (the transition from motor running to engine running) is less than when automatic running is not performed. Responsiveness) does not matter much.
[0007]
The present invention has been made in view of such a technical problem that has been uniquely found, and during motor driving with a fuel cut, by controlling the throttle opening in accordance with the presence or absence of automatic driving, fuel efficiency is improved. It is a main object of the present invention to provide a new hybrid vehicle control device capable of effectively achieving both improvement in responsiveness and responsiveness.
[0008]
[Means for Solving the Problems]
The motor includes a motor connected to the engine and drive wheels, and a throttle for opening and closing the intake passage of the engine. The vehicle is provided with automatic traveling means such as an automatic speed control device for automatically traveling to keep at least one of the traveling speed and the inter-vehicle distance of the vehicle constant. During motor running in which fuel supply to the engine is stopped and drive wheels are driven by the motor, the motor drives the crankshaft of the engine to rotate, that is, idle. During the motor running, the throttle opening is controlled so that the throttle opening is larger when the vehicle is running automatically than when the vehicle is not running automatically.
[0009]
【The invention's effect】
When the motor is running and the vehicle is running automatically, the throttle opening is relatively large compared to when the vehicle is not running automatically, so pump loss is reduced and fuel efficiency is improved. Can be. However, since the opening degree of the throttle is relatively large, the responsiveness of the transition from the motor running to the engine running is relatively reduced, but the demand for the responsiveness during the automatic running is low, and there is no practical problem.
[0010]
When the vehicle is not running automatically, for example, it is necessary to quickly accelerate and decelerate following the accelerator operation of the driver, and there is a high demand for responsiveness. According to the present invention, when the motor is running and the vehicle is not running automatically, the opening degree of the throttle is made relatively small. It also has excellent responsiveness to the like.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic configuration diagram showing a hybrid vehicle to which a control device according to one embodiment of the present invention is applied. This vehicle is a hybrid vehicle that uses both an engine 11 and a drive motor 12 as a vehicle propulsion source that rotationally drives a drive wheel 10. The engine 11 and the drive motor 12 are directly connected, that is, directly connected by the shaft 13, and rotate integrally. A belt-type continuously variable transmission 15, a speed reducer 16, and a differential gear 17 are provided in a power transmission path from the engine 11 and the drive motor 12 to the drive wheels 10. Further, a generator 21 is connected to the engine 11 via a belt 18 and pulleys 19 and 20.
[0012]
The engine 11 is, for example, an in-line four-cylinder gasoline engine. A throttle 23 for adjusting the amount of intake air is provided upstream of the collector in the intake passage 22 of the engine 11, and a muffler 26 is provided in the exhaust passage 25. The throttle 23 is an electromagnetic throttle valve, and its opening is controlled by an engine ECU 35, which will be described later, mainly in accordance with the operation of an accelerator pedal 44 in an engine running mode or the like. It is also possible to change and control the degree.
[0013]
Both the drive motor 12 and the generator 21 are three-phase AC type motor generators electrically connected to a battery 28 that stores power via an inverter 27, and can perform both power running operation and regenerative operation. However, the drive motor 12 mainly functions as an electric motor for powering and driving the drive wheels 10, and the generator 21 mainly functions as a generator driven by the engine 11 to regenerate electric power.
[0014]
In this vehicle, a plurality of electronic control units (ECUs) 30 to 35 are provided for each functional unit such as an engine, and all ECUs operate in synchronization under a single hybrid ECU 30 while sharing information. Controller, area network, etc.). Each ECU is a known digital computer that can store and execute various control processes.
[0015]
The battery ECU 31 performs, for example, current accumulation based on detection signals of a voltage sensor 41 that detects a voltage of the battery and a current sensor 42 that detects a charging / discharging current of the battery, and stores a charged amount of the battery, that is, an SOC (state of charge). Charge). Generator ECU 32 controls the rotation speed and torque of generator 21. The motor ECU 33 controls the rotation speed and torque of the drive motor 12. The CVT ECU 34 controls the speed of the continuously variable transmission 15. The engine ECU 35 controls the fuel injection amount and timing of the engine 11, the ignition timing, the throttle opening, and the like.
[0016]
The hybrid ECU 30 sends to the hybrid ECU 30 various signals representing the vehicle driving state, in addition to the SOC from the battery ECU 31, a vehicle speed signal detected by a vehicle speed sensor 43, and an opening signal of an accelerator pedal 44 corresponding to a driver's acceleration request. , A hydraulic pressure signal of the brake master cylinder 46 corresponding to the opening of the brake pedal 45, a signal of a setting switch 47 of an automatic speed controller (ACC; adaptive cruise control), and the like. Based on these signals, the hybrid ECU 30 outputs control signals to the ECUs 32 to 35, various actuators, and the like, and controls the operation of the entire vehicle as a whole.
[0017]
As the setting switch 47 of the above-mentioned automatic speed control device, in addition to a main switch for turning on / off the automatic traveling by this device, a vehicle speed setting switch for setting a target / desired set vehicle speed in a range of 40 to 100 km / h, for example. A set vehicle speed increase switch that increases the vehicle speed at intervals of, for example, 5 km / h, a set vehicle speed lowering switch that decreases the set vehicle speed at intervals of, for example, 5 km / h, and a set inter-vehicle distance is switched between, for example, “long”, “medium”, and “short”. A set inter-vehicle distance switch and the like are provided. During automatic running (follow-up running) by the automatic speed control device, basically, when there is no preceding vehicle, automatic constant speed running is performed to maintain the vehicle speed at the set vehicle speed, and when there is a preceding vehicle, the set vehicle speed is set. Is performed and the set inter-vehicle distance is kept as an upper limit (automatic traveling means).
[0018]
As a driving mode of the vehicle, an engine running mode in which fuel is injected and supplied to the engine 11 and the driving wheels 10 are mainly driven by the driving force generated by the engine 11 and a so-called fuel cut in which the fuel supply to the engine 11 is stopped are performed. There is a motor running mode (motor running means) in which the driving wheels 10 are driven only by the driving force of the drive motor 12, and both modes are switched by the hybrid ECU 30 according to the vehicle driving state. In the engine running mode, the driving motor 12 may be driven by power as needed, and the driving motor 12 may assist the vehicle propulsion. In the motor running mode, the crankshaft of the engine 11 directly connected to the drive motor 12 is also driven to rotate. That is, the crankshaft of the engine 11 idles and rotates. For this reason, when the motor is traveling with a fuel cut, the fuel efficiency is reduced by the loss of the engine friction and the pump loss. Even if the clutch is provided between the engine 11 and the drive motor 12, if the motor is run with the clutch engaged in preparation for the next start of the engine, the crankshaft runs idle and the pump Incurs losses and the like.
[0019]
The above-described pump loss during motor running can be reduced by opening the throttle 23. However, when the throttle 23 is opened, the negative pressure downstream of the throttle is reduced. Therefore, when shifting from the motor running to the engine running by depressing the accelerator, changing the set vehicle speed during automatic running, increasing running resistance due to climbing a hill, or the like. In order to prevent the amount of intake air flowing into the cylinder from increasing excessively and the combustion torque from increasing rapidly, the negative pressure downstream of the throttle is sufficiently developed to reduce the amount of intake air into the cylinder sufficiently. It is necessary to supply fuel and ignite after waiting. However, even if the throttle 23 is closed due to a response delay or the like due to the intake pipe volume, the negative pressure does not develop immediately, and there is a concern that the responsiveness may decrease. In this embodiment, when the motor is running, the throttle opening is controlled in accordance with the presence or absence of the automatic running (throttle control means), thereby improving the fuel efficiency and the responsiveness by reducing the pump loss. At a high level.
[0020]
FIG. 2 is a flowchart illustrating a flow of control forming a main part of the present embodiment. This control is started when the ignition switch is turned on by the hybrid ECU 30, for example, and is repeatedly executed at predetermined intervals (for example, 10 ms).
[0021]
In S (step) 10, it is determined whether the SOC is equal to or more than a predetermined value. In S20, the target driving force of the vehicle is compared with a motor traveling lower limit value which is a lower limit value of the driving force at which the motor traveling can be stably performed. For example, as shown in FIG. 3, the target driving force is calculated by mapping the vehicle speed and the accelerator opening to a target driving torque setting map 50 which is set and stored in advance, and a target driving torque is calculated. It is calculated by multiplying the driving torque by the vehicle speed. The above-mentioned motor running lower limit value is calculated by multiplying a value obtained by subtracting a margin electric power from a usable electric power of the driving motor (motor driving electric power) calculated based on the SOC, electric power distribution, and the like, for example, and then multiplying the efficiency. The margin power is set in consideration of the driving force so as to guarantee the necessary driving force during the transition from the motor running to the engine running. The above efficiency is set in consideration of the electric loss of the drive motor 12.
[0022]
Referring to FIG. 2 again, if both S10 and S20 are affirmed, that is, if the SOC is equal to or more than the predetermined value and the target driving force is equal to or less than the motor driving lower limit value, the process proceeds to S30 and S40. Proceed, permitting the motor running, and permitting the fuel cut. Specifically, each permission flag is set (set to 1). Thus, the motor running is performed by another routine (not shown). That is, the supply of fuel to the engine 11 is stopped (fuel cut), and the drive wheels 10 are driven only by the drive motor 12. The power generated by the drive motor 12 causes the crankshaft of the engine 11 to idle and follow.
[0023]
In S50, it is determined whether the vehicle is traveling automatically. Specifically, it is determined whether the main switch of the setting switch 47 of the above-described automatic speed control device is turned on.
[0024]
If it is determined in S50 that the vehicle is not running automatically, the process proceeds to S60, and a throttle close request is output to the engine ECU 35. Thereby, the engine ECU 35 changes and controls the opening degree of the throttle 23 to the fully closed state. As described above, when it is determined that the vehicle is traveling by the motor and that the vehicle is not traveling automatically, the throttle 23 is fully closed. Therefore, the negative pressure downstream of the throttle is sufficiently maintained even during the motor running with the fuel cut, and the responsiveness is improved at the next shift to the engine running.
[0025]
If it is determined in S50 that the vehicle is traveling automatically, the process proceeds to S90 via S70 described later, and the target throttle opening is calculated. Specifically, as shown in FIG. 3, the accelerator opening and the vehicle speed are mapped on a target driving torque setting map 50 of the vehicle which is set and stored in advance, and a target driving torque is calculated. The target driving force is calculated by multiplying the driving torque by the SOC. The target driving force and the SOC are mapped to a target throttle opening setting map 52 set and stored in advance to calculate a target throttle opening.
[0026]
FIG. 4 schematically shows the target throttle opening degree setting map 52 described above. In the transitional period from the motor running to the engine running, the vehicle must be driven by the drive motor 12 until the negative pressure is sufficiently developed. It depends on the driving force and the SOC. Therefore, the target throttle opening is set according to the target driving force and the SOC. Specifically, the larger the target driving force, the smaller the target throttle opening. Further, the target throttle opening is increased as the SOC increases. Further, in a situation where the SOC is higher than a certain value, electric power can be supplied to the drive motor 12 with a margin during the transition to the engine drive mode, so that the target throttle opening is set to the maximum value for each target drive force. The target throttle opening calculated in S90 is transmitted to the engine ECU 35, and the engine ECU 35 controls the throttle 23 toward the target throttle opening.
[0027]
As described above, when the motor is traveling and the vehicle is traveling automatically, the throttle 23 is opened based on the target driving force and the SOC, so that pump loss can be reduced and fuel efficiency can be improved. . By opening the throttle, the responsiveness of the transition from the motor running to the engine running is reduced, but as described above, the demand for the responsiveness is relatively low during the automatic running, so that there is no practical problem. .
[0028]
Referring to FIG. 2 again, in S70, it is determined whether the fuel cut is being performed, that is, whether the fuel cut process is completed. Until the fuel cut is completed, S90 is bypassed. After the fuel cut is completed, the process proceeds from S70 to S90, and the throttle opening is calculated. That is, the opening control of the throttle 23 is prohibited until the fuel cut is completed. Thus, there is no possibility that the throttle 23 is opened carelessly before the fuel cut is completed, which may cause a decrease in combustion stability, and the stability and reliability are excellent.
[0029]
In the above S10, if it is determined that the SOC is less than the predetermined value, and if the motor running is continued or started, there is a possibility that the motor running and the engine running may be hunting. Prohibit motor travel with cutting. Also in S20, if the target driving force exceeds the motor running lower limit value, the process proceeds to S100, and the motor running with fuel cut is prohibited. Specifically, the above-mentioned motor running permission flag is set to 0. In response to this, by another routine (not shown), for example, when the motor is running, the mode is shifted to the engine running mode, the throttle 23 is closed and the negative pressure is sufficiently developed, and then the fuel injection is started. I do.
[0030]
In subsequent S105, it is determined whether or not the transition from the motor running to the engine running is being performed, that is, it is in a transition transition period. If it is determined that it is the transition transition period, the process proceeds from S105 to S110, in which a request to close (fully close) the throttle 23 is output to the engine ECU 35, and the closing of the throttle 23 is started. In S120, it is determined whether the closing of the throttle 23 has been completed, that is, whether the throttle 23 has been fully closed. When it is confirmed that the throttle 23 is fully closed, the process proceeds from S120 to S130, and the fuel cut is prohibited. That is, the fuel cut is canceled and the fuel injection is started.
[0031]
If the fuel supply is started before the throttle 23 is completely closed during the transition from the motor running to the engine running, the filling air in the cylinder becomes excessive, the combustion torque rises rapidly, and the There is a risk of giving a rushing feeling. On the other hand, in the present embodiment, since the cancellation of the fuel cut is prohibited until the closing of the throttle 23 is completed by the processing of S110 to S130, there is no possibility of giving the above-mentioned rushing feeling, and the stable You can drive.
[0032]
In the above-described embodiment, the automatic speed control device that controls the distance between the vehicle and the preceding vehicle or the traveling speed of the own vehicle is described as a combination. However, the function of controlling the traveling speed of the own vehicle constant is described. It is needless to say that the same effect can be obtained even in combination with an automatic speed control device having only an automatic speed control device (constant speed traveling control device ASCD; auto speed control device).
[0033]
As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above embodiments, and includes various modifications and changes without departing from the gist of the present invention. . For example, the present invention can be applied to a hybrid vehicle in which a transmission such as a planetary gear mechanism is incorporated between an engine and a drive motor.
[Brief description of the drawings]
FIG. 1 is a configuration diagram schematically showing a hybrid vehicle to which a control device according to an embodiment of the present invention is applied.
FIG. 2 is a flowchart showing a control flow according to the embodiment.
FIG. 3 is an explanatory diagram showing a process for calculating a target driving force and a target throttle opening.
FIG. 4 is a setting map of a target throttle opening.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Drive wheel 11 ... Engine 12 ... Drive motor 23 ... Throttle 28 ... Battery 30 ... Hybrid ECU

Claims (5)

A motor connected to the engine and drive wheels,
A throttle that opens and closes the intake passage of the engine,
Automatic traveling means for automatic traveling for automatically maintaining at least one of the traveling speed of the vehicle and the inter-vehicle distance constant;
Motor running means for stopping the fuel supply to the engine and driving the drive wheels by the motor, and running the motor with the crankshaft of the engine being rotationally driven by the motor;
A throttle control means for controlling the throttle opening so that the throttle opening is larger when the motor is running than when the vehicle is not running automatically during the motor running. apparatus. A power storage battery electrically connected to the motor, means for calculating an amount of power stored in the battery, and means for calculating a target driving force of the vehicle,
The throttle control means closes the throttle fully when the automatic driving is not being performed, and sets the throttle opening based on the charged amount of the battery and the target driving force of the vehicle when the automatic driving is being performed. The control device for a hybrid vehicle according to claim 1, wherein the control is performed. 3. The throttle control device according to claim 2, wherein the throttle control means increases the throttle opening as the charged amount of the battery increases, and decreases the throttle opening as the target driving force of the vehicle increases, during the automatic running. Control device for hybrid vehicle. The control of the hybrid vehicle according to any one of claims 1 to 3, wherein fuel supply to the engine is prohibited until the throttle is closed during a transition period from the motor running to the engine running in which driving wheels are mainly driven by the engine. apparatus. A storable battery electrically connected to the motor;
Means for calculating the charged amount of the battery;
Means for calculating a target driving force of the vehicle;
Means for calculating a motor running lower limit capable of stably performing the motor running, the motor running lower limit being a predetermined margin electric power from the motor usable electric power calculated from the charged amount of the battery. Calculated by multiplying the deducted value by a predetermined efficiency,
And means for comparing the target driving force with the motor traveling lower limit value,
Means for permitting motor travel when the amount of charge of the battery is equal to or greater than a predetermined value and the target driving force is equal to or less than the motor travel lower limit;
The control device for a hybrid vehicle according to any one of claims 1 to 4, further comprising: means for prohibiting motor driving when the amount of charge of the battery is less than a predetermined value or when the target driving force exceeds the motor driving lower limit.

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