JP2012117402A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control device that is capable of expanding an operation region of an alternator by actuating the alternator in a region not deteriorating a fuel economy rate.SOLUTION: The optimum fuel economy line and a fuel economy rate map based on engine torque and an engine rotation speed are stored in advance. The current position on the fuel economy rate map in a non-actuation state of an alternator is estimated on the basis of an engine drive state. When the estimated current position is closer to a low-torque region side than to the optimum fuel economy line, a torque difference ΔT being the torque difference between the estimated current position and the optimum fuel economy line is obtained, and the engine torque is increased by a torque-up means in accordance with the torque difference ΔT. When the torque difference ΔT is smaller than the maximum load torque Ta of the alternator, the actuation of the alternator is inhibited. When the torque difference ΔT is larger than the maximum load torque Ta of the alternator, the actuation of the alternator is allowed.

Description

The present invention relates to a vehicle control device including an engine, a belt-type continuously variable transmission, and an alternator, and more particularly to a control device that improves fuel consumption and prevents battery deterioration.

In a conventional vehicle, when the battery is deteriorated, the alternator has a function of automatically generating power when it is detected. However, if the battery is not deteriorated, it is desired to reduce the alternator load as much as possible and increase the output torque. For this reason, a method has been implemented in which power generation by the alternator is concentrated in deceleration (fuel cut) to improve fuel efficiency. However, if power generation is concentrated only during deceleration, battery charging may be insufficient.

In particular, in the case of a continuously variable transmission, when the vehicle speed becomes low, the secondary pressure increases due to the low return, resulting in an increase in the load of the oil pump and further increase in deceleration. Therefore, in a vehicle equipped with a continuously variable transmission, if power generation is concentrated only at the time of deceleration, power generation by the alternator can be performed only in a limited region, and the power balance is deteriorated, which easily causes battery deterioration.

Patent Document 1 discloses a vehicle control device for suppressing battery deterioration and fuel consumption deterioration. That is, the amount of electricity required for power generation is calculated from the battery state, the torque required for the engine is calculated from the running state, the vehicle required torque is determined by arbitrating between the amount of electricity required for power generation and the engine required torque, and thereby the target engine speed It is characterized by determining.

In this case, the target engine speed is determined from the amount of electricity required for power generation and the required torque of the engine. However, in the case of a vehicle equipped with a continuously variable transmission, the target input speed (at lockup) Since the target engine speed is set and feedback control is performed, there is a possibility that the above-described torque control and the transmission control of the continuously variable transmission interfere with each other. Moreover, there is no description regarding a transmission in patent document 1, and it is unknown what kind of control is performed. Since the load torque is changed by the operation of the alternator, the fuel consumption may be worse than in the current driving state in the control as described above.

JP 2007-239526 A

An object of the present invention is to provide a vehicle control device that can expand an operation range of an alternator by operating the alternator in a region where the fuel consumption rate does not deteriorate.

In order to achieve the above object, the present invention is a vehicle comprising an engine, a belt-type continuously variable transmission, and an alternator driven by the engine, and driving wheels via the continuously variable transmission by engine power. The continuously variable transmission determines a target input speed corresponding to the accelerator opening and the vehicle speed, and feedback-controls the speed ratio toward the target input speed, and the engine increases the engine torque. In a vehicle provided with torque-up means for causing the fuel consumption rate map to be stored based on the engine torque and the engine speed and the optimum fuel consumption line in advance, the fuel consumption rate in the non-operating state of the alternator from the engine driving state is stored. Means for estimating a current position on a map; and when the estimated current position is on a lower torque region side than the optimum fuel consumption line, A means for obtaining a torque difference ΔT between the shape position and the optimum fuel consumption line, a means for increasing the engine torque by the torque-up means according to the torque difference ΔT, and the torque difference ΔT is a maximum load torque of the alternator. A vehicle control device comprising: means for prohibiting the operation of the alternator when smaller than Ta, and permitting the operation of the alternator when the torque difference ΔT is larger than the maximum load torque Ta of the alternator. provide.

In the present invention, the current position on the fuel consumption rate map in the non-operating state of the alternator is estimated from the engine driving state, and when this estimated current position is on the low torque region side of the optimal fuel consumption line, the estimated current position and the optimal fuel consumption By obtaining a torque difference ΔT with respect to the line and increasing the engine torque in accordance with the torque difference ΔT, the current position is brought closer to the optimum fuel consumption line. The increase in engine torque can be easily performed using a known torque-up means (for example, an electronic throttle, an ignition timing control device, etc.). Next, the torque difference ΔT is compared with the maximum load torque Ta of the alternator. When ΔT <Ta, the alternator operation is prohibited, and when ΔT ≧ Ta, the alternator operation is permitted. In other words, even when the load torque of the alternator becomes maximum, by permitting the operation of the alternator only when the torque increasing action can be obtained, the fuel consumption is deteriorated by the operation of the alternator or the driving torque of the vehicle is lower than the current state. Can be prevented. Furthermore, while the operation range of the alternator is limited during deceleration in a vehicle equipped with a conventional continuously variable transmission, the present invention allows the alternator to operate in a region other than during deceleration. Can be improved and battery deterioration can be prevented.

There are two types of alternators: a simple type with only ON / OFF control and a load adjustment type. In the former case, it can be used only in an area where the fuel consumption does not deteriorate, but the control is simple. In the case of the load adjustment type, for example, by changing the required power generation amount, the load torque can be freely changed, so that the operating range of the alternator can be further expanded.

As described above, according to the present invention, it becomes possible to operate the alternator even in a region other than during deceleration, so that the deterioration of the battery can be suppressed and the alternator is operated only in a region where the deterioration of fuel consumption is small. Deterioration of fuel consumption due to operation of the alternator can be suppressed. Moreover, since it can suppress that the drive torque of a vehicle falls by the action | operation of an alternator, there is no sense of incongruity during driving | running | working.

1 is a system diagram of a vehicle according to the present invention. It is a speed change characteristic figure of a continuously variable transmission. It is a figure which shows the relationship between the rotation speed of an engine, and a torque. It is a flowchart figure of an example of the operation control of the alternator which concerns on this invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a vehicle system according to the present invention. The engine 1 is provided with a known torque-up device (electronic throttle, ignition timing control device, etc.) 12. The engine output shaft 11 is connected to an input shaft (turbine shaft) 20 of the continuously variable transmission 2 via a torque converter 3 with a lock-up clutch. The input shaft 20 is connected to a drive shaft 25 via a belt type continuously variable transmission mechanism 21 to drive a wheel. Note that other mechanisms such as a forward / reverse switching mechanism are not shown. As is well known, the continuously variable transmission mechanism 21 wraps a belt 24 between a primary pulley 22 and a secondary pulley 23 and changes the belt wrapping diameters of the pulleys 22 and 23 to change the speed ratio. It will change in stages.

The continuously variable transmission 2 is provided with a hydraulic control device 26 for operating the pulleys 22 and 23 and for controlling the lock-up clutch of the torque converter 3. The hydraulic control device 26 includes a plurality of solenoid valves. By controlling these solenoid valves with the control unit 40, the continuously variable transmission mechanism 21 is controlled to be shifted, and the lockup clutch is connected and disconnected. In general, the shift control is performed by controlling the flow rate of the hydraulic oil supplied to the oil chamber of the primary pulley 22, and the belt clamping pressure control is performed by controlling the pressure of the hydraulic oil supplied to the oil chamber of the secondary pulley 23. Is done.

An alternator 15 is provided in the vicinity of the engine 1, and this alternator 15 is driven by the output shaft 11 of the engine 1 via a belt 16. In the alternator 15 of this embodiment, the load torque is automatically determined by switching the voltage ON / OFF. An alternator that can electrically change the load torque by changing the required power generation amount by the control unit 40 may be used.

The control unit 40 includes vehicle speed (secondary rotational speed), accelerator opening (throttle opening), engine speed, primary pulley rotational speed (input rotational speed), brake signal, P, R, N, D, L, etc. Signals are input from various sensors 41 to 47 that detect a shift position, battery voltage, and the like, and the engine 1 and the continuously variable transmission 2 are controlled in an integrated manner, and the alternator 15 is also controlled. The memory of the control unit 40 stores an engine control program, a continuously variable transmission control program, an alternator control program, and various data. Since engine control and continuously variable transmission control are known per se, detailed description thereof is omitted.

A shift characteristic map of the continuously variable transmission 2 is set in the control unit 40 in advance. For example, as shown in FIG. 2, the speed change characteristic map has a target input rotational speed (target primary rotational speed) on the vertical axis and a vehicle speed (secondary rotational speed) on the horizontal axis, and the accelerator opening (or throttle opening). It is set as a parameter. In FIG. 2, four characteristics of accelerator opening 0%, 25%, 50%, and 100% are shown. Normally, these characteristics are set to characteristics substantially along the optimal fuel consumption line of the engine at each accelerator opening in the traveling pattern for fuel efficiency evaluation. However, in general driving conditions, it is often the case that the engine deviates from the optimum fuel consumption line.

The control unit 40 obtains a target input rotational speed (target primary rotational speed) from the vehicle speed and the accelerator opening during traveling, and changes the gear ratio (the amount of oil to the primary pulley so that the actual input rotational speed approaches the target input rotational speed). ) To control. Further, the belt clamping pressure is determined according to the load torque, and the hydraulic pressure of the secondary pulley is controlled to the target belt clamping pressure.

FIG. 3 shows an example of an engine fuel consumption rate map and an optimum fuel consumption line stored in the control unit 40 in advance. The fuel consumption rate map is represented by contour lines plotting the engine speed and the position of the engine torque at the equal fuel consumption rate, and the fuel efficiency rate is better at the center. The optimum fuel consumption line is a line depicting characteristics that can achieve the best fuel consumption state of the engine, and is represented by a line connecting the intersections of the equal fuel consumption rate line and the equal output line.

For example, it is assumed that point A in FIG. 3 is the current traveling state. The torque-up device 12 performs, for example, an increase in the electronic throttle opening degree or control of the ignition timing in order to improve the fuel consumption in the traveling state at the current time A to the state B of the optimal fuel consumption line without changing the engine speed. To increase the engine torque as shown by the arrow. At that time, if the battery voltage is lower than the reference value, it is desirable to operate the alternator. However, since the operation of the alternator was limited to the time of deceleration conventionally, the alternator could not be operated. In the present invention, by operating the alternator during such engine torque amplification, the operating range of the alternator is expanded and the battery is prevented from deteriorating. However, driving the alternator generates load torque, and depending on the load torque, there is a possibility that the fuel efficiency is worse than the current point A. Therefore, in the present invention, the engine torque increase value is compared with the maximum load torque of the alternator, and even if the alternator is operated, the fuel efficiency rate line at the present time A is not deteriorated, and the alternator only in a region where the drive torque of the vehicle does not decrease. Allow operation.

FIG. 4 shows an example of the operation control of the alternator according to the present invention. First, the current engine speed is detected (step S1), and the current engine torque A is calculated from the fuel consumption rate map at the same speed (step S2). Next, the engine torque (optimum torque) B of the optimum fuel consumption line at the same engine speed as the current engine speed is read (step S3), and the torque difference (ΔT) between the optimum torque B and the current torque A is calculated (step S3). Step S4). This torque difference becomes the power generation possible torque.

Next, a battery voltage or the like is detected to determine whether charging is necessary (step S5). If charging is necessary, the maximum load torque Ta when the alternator is driven is compared with the power generation possible torque ΔT (step S6), and if ΔT ≧ Ta, the operation of the alternator is permitted (step S7). That is, the torque-up control is performed to the engine torque value corresponding to the optimum fuel consumption line together with the operation of the alternator. If it is not necessary to charge the battery or ΔT <Ta, the operation of the alternator is prohibited and only torque-up control is performed (step S8). By this control, it becomes possible to drive the alternator 15 at times other than during deceleration, so that the power balance can be improved and the deterioration of the battery can be prevented. Further, since the torque increase device 12 increases the engine torque so as to approach the optimum fuel consumption line, it is possible to prevent a situation in which the fuel consumption is worse than the current time due to the operation of the alternator 15, and to reduce the driving torque of the vehicle (the continuously variable transmission). Output side torque) does not decrease from the current level, so that a sense of incongruity during traveling can be prevented.

In the above embodiment, the operation / non-operation of the alternator is determined by comparing the power generation possible torque ΔT and the maximum load torque Ta of the alternator. However, when the maximum load torque of the alternator can be adjusted, the maximum load torque of the alternator is determined. The alternator may be operated after setting the maximum load torque Ta so that Ta does not exceed the torque difference ΔT. For example, there is a regulator that adjusts the field current of a field coil of an alternator, and the power generation amount of the alternator can be adjusted by inputting a duty signal called F duty to the regulator. In this case, after calculating the power generation possible torque ΔT (step S4), the F duty ratio may be calculated from the power generation possible torque ΔT, and the F duty ratio may be indicated to control the alternator load. In this case, the alternator can be operated even in a region where the power generation possible torque ΔT is smaller than the maximum load torque Ta, and the alternator can be operated in a wider region.

DESCRIPTION OF SYMBOLS 1 Engine 2 Continuously variable transmission 3 Torque converter 12 Torque-up apparatus 15 Alternator 20 Input shaft 22 Primary pulley 23 Secondary pulley 24 Belt 25 Output shaft (drive shaft)
26 Hydraulic control device 40 Control unit 41 Vehicle speed sensor 42 Accelerator opening sensor 43 Engine speed sensor 44 Turbine (primary) speed sensor 47 Battery voltage sensor

Claims (1)

A vehicle comprising an engine, a belt-type continuously variable transmission, and an alternator driven by the engine, and driving wheels via the continuously variable transmission by engine power,
The continuously variable transmission determines a target input speed corresponding to the accelerator opening and the vehicle speed, and feedback-controls the speed ratio toward the target input speed,
In the vehicle provided with torque-up means for increasing the engine torque,
Storage means for storing in advance a fuel consumption rate map based on engine torque and engine speed and an optimum fuel consumption line;
Means for estimating a current position on the fuel efficiency map in an inoperative state of the alternator from an engine driving state;
Means for obtaining a torque difference ΔT, which is a torque difference between the estimated current position and the optimum fuel consumption line, when the estimated current position is on a lower torque region side than the optimum fuel consumption line;
Means for increasing engine torque by the torque-up means according to the torque difference ΔT;
Means for prohibiting the operation of the alternator when the torque difference ΔT is smaller than the maximum load torque Ta of the alternator, and permitting the operation of the alternator when the torque difference ΔT is larger than the maximum load torque Ta of the alternator;
A vehicle control device comprising:

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