JP2004257442A - Vehicular control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve fuel consumption by prolonging the fuel cut time by reliably couple a lockup clutch when a vehicle is decelerated. <P>SOLUTION: A lockup control device for vehicle has a lockup clutch to uncouple an engine 1 from an automatic transmission 3, auxiliary machinery to be driven by the rotation of the engine 1, and a lockup clutch coupling means to couple the lockup clutch when the vehicle is decelerated, and is further provided with an auxiliary machinery load reducing means to reduce the load on the auxiliary machinery. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to control of a vehicle including an auxiliary device and a torque converter having a lock-up clutch.
[0002]
[Prior art]
There is a method of improving fuel efficiency by performing a fuel cut to temporarily suspend the supply of fuel to the engine at the time of deceleration. However, by performing the fuel cut, the decrease in the engine speed is accelerated, and if the engine speed is reduced too much during the fuel cut at the time of deceleration, the engine may be stalled when the fuel supply is restarted. The area was small. In addition, if the load on the auxiliary equipment such as the air conditioner is large when the fuel supply is restarted, the engine may be similarly stalled.
[0003]
Therefore, during the fuel cut, the lock-up clutch provided in the torque converter of the automatic transmission is engaged to transmit the rotation of the drive wheels to the engine to maintain the engine rotation speed, and to execute the lock-up of the air conditioner compressor during the lock-up. Patent Document 1 discloses a control device that further reduces the speed of decrease in engine rotation by reducing the engine speed, widens the execution area of fuel cut during deceleration, and improves fuel efficiency.
[0004]
[Patent Document 1]
JP, 2002-234340, A
[Problems to be solved by the present invention]
However, the control method described in Patent Document 1 reduces the capacity of the air conditioner compressor (A / C compressor) after the lock-up clutch is engaged. When the load on the air-conditioning compressor is large, the engine speed drops rapidly when the accelerator is off, and the deviation from the torque converter speed increases, so that it is easy to fail to engage the lock-up clutch. The area where cutting can be performed was narrow.
[0006]
Therefore, an object of the present invention is to improve the fuel efficiency by quickly and reliably engaging the lock-up clutch at the time of deceleration, thereby increasing the time for performing the fuel cut.
[0007]
[Means for Solving the Problems]
A vehicle control device according to the present invention includes a lock-up clutch that disconnects an engine and an automatic transmission, an auxiliary device that is driven by rotation of the engine, and a lock-up that engages the lock-up clutch when the vehicle decelerates. And an auxiliary equipment load reducing means for reducing a load on the auxiliary equipment prior to the engagement of the lock-up clutch at the time of deceleration.
[0008]
[Action / Effect]
According to the present invention, prior to engagement of the lock-up clutch at the time of deceleration, the load on the accessory is reduced, so that failure of engagement of the lock-up clutch can be prevented even when the load on the accessory is large. become. As a result, it is possible to increase the time for performing the fuel cut, thereby improving the fuel efficiency.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0010]
FIG. 1 is a diagram showing an outline of the system of the first embodiment. The output shaft of the engine 1 is connected to a transmission 3 via a torque converter 2 that transmits torque via an internal differential fluid, and further connected to drive wheels (not shown) through the transmission 3.
[0011]
The torque converter 2 includes a lock-up clutch 2a, and the operation thereof causes the engine 1 and the transmission 3 to be directly connected.
[0012]
Reference numeral 4 denotes a transmission control unit (hereinafter, referred to as a transmission ECU) that controls a shift operation between the torque converter 2 and the transmission 3 and reads a differential rotation speed and the like. Reference numeral 5 denotes a control unit (hereinafter, referred to as an ECU) that controls the entire system. Reference numeral 6 denotes a power generation controller (hereinafter, referred to as USM) that controls a generator (alternator) 9 based on the generated voltage amount calculated by the ECU 5, and 7 denotes an air conditioner amplifier that controls an air conditioner compressor 8 based on a signal from the ECU 5. (Hereinafter, referred to as A / C amplifier).
[0013]
In the present embodiment, when the vehicle is decelerated, the ECU 5 performs control to reduce the load on the auxiliary devices such as the air conditioner compressor 8 and the alternator 9 prior to the engagement of the lock-up clutch 2a.
[0014]
FIG. 3 shows a control flow of the present embodiment executed by the ECU 5.
[0015]
In step S100, it is determined whether or not the current area is the lock-up permission area with reference to the table of FIG. If not, the process proceeds to step S107, and the process ends.
[0016]
FIG. 2 is a diagram showing an area where lock-up control can be performed during deceleration. Dotted line A indicates the boundary between the 4th and 3rd speed shifts (hereinafter referred to as 3-4 shift line). The accelerator opening is constant from zero to about 15 degrees at a vehicle speed of about 40 km / h. At the above accelerator opening, the vehicle speed increases in proportion to the accelerator opening.
[0017]
Dotted line B indicates the boundary between the 5th and 4th speed shifts (hereinafter referred to as the 4-5 shift line), and the accelerator opening is constant from fully closed to about 15 degrees while the vehicle speed is about 60 km / h. At the above accelerator opening, the vehicle speed increases in proportion to the accelerator opening.
[0018]
Accordingly, it can be seen from FIG. 2 that if the accelerator opening is larger than the dotted line A, the third speed is set, if the accelerator opening is between the dotted lines A and B, the fourth speed is set, and if the accelerator opening is smaller than the dotted line B, the fifth speed is set.
[0019]
A region C having a vehicle speed of about 55 km / h or more indicated by oblique lines and having an accelerator opening of about 10 degrees from zero is a lock-up permission area, and a constant vehicle speed of about 50 km / h is provided from zero to about 12 degrees of accelerator opening. A dotted line D in which only the vehicle speed increases with the accelerator opening kept at about 12 degrees indicates a boundary line for releasing lockup (hereinafter referred to as a lockup release line).
[0020]
In step S101, the capacity correction time (initial value of the timer) of the auxiliary equipment (air conditioner compressor 8) is calculated with reference to the table of FIG. 7, and the process proceeds to step S102. FIG. 7 is a table for searching for a correction time from a differential rotation speed (hereinafter referred to as an operation rotation speed) between the engine rotation speed and the torque converter rotation speed when the accelerator is turned off, and the differential rotation speed is less than 50 rpm. The correction time is 1 sec, and the correction time is 2 sec at 50 rpm or more.
[0021]
In step S102, the timer initial value calculated in step S101 is set in the timer, and the process proceeds to step S103.
[0022]
In step S103, referring to the table in FIG. 8, a correction torque amount necessary for securely engaging the lock-up clutch is calculated from the current differential speed of the torque converter, and the process proceeds to step S104. The table in FIG. 8 shows the relationship between the differential rotation speed of the torque converter and the torque correction amount, and the torque correction amount increases in proportion to the increase in the operating rotation speed.
[0023]
In step S104, an operation degree change amount is calculated so as to reduce the load on the air conditioner compressor 8 according to the correction torque amount obtained in step S103, and the process proceeds to step S105. The operation degree change amount is calculated by the ECU 5, and the operation degree is controlled by the air conditioner amplifier 7 according to a signal from the ECU 5. Since the specific method is a known technique, the description is omitted.
[0024]
In step S105, a timer value is obtained by subtracting 1 from the timer initial value set in step S102, and the process proceeds to step S106.
[0025]
In step S106, it is determined whether the value obtained in step S105 is zero. If the value is zero, the process proceeds to step S107, in which the operation degree correction of the air conditioner compressor 8 is prohibited, and the process ends. If the value is not zero, the process proceeds to step S103, in which a correction torque amount is calculated from the torque converter differential rotation speed at that time, and the above processing is repeated until the timer value becomes zero in step S106.
[0026]
The above control will be described with reference to the time chart of FIG.
[0027]
When the accelerator is turned off at t1, the engine speed and the torque converter speed begin to decrease. At this time, the speed at which the torque converter rotation speed decreases is smaller than the engine rotation speed. This is because the load of auxiliary equipment acting as a rotational resistance acts on the engine, while the inertia force of the driving wheels connected acts on the torque converter.
[0028]
At t1, the operating degree (load) of the air conditioner compressor 8 is reduced according to the flowchart of FIG.
[0029]
If the auxiliary equipment load (the operation degree of the air conditioner compressor 8) is not reduced as in the conventional case, the decrease in the engine speed is large as indicated by the dashed line A, and the difference from the torque converter speed is large. Therefore, there is a high possibility that the engagement of the lock-up clutch 2a will fail. In the event of failure, it is necessary to inject fuel to maintain the engine speed in an idling state. Disappears.
[0030]
In the present embodiment, the load on the auxiliary equipment is reduced by lowering the operation degree of the air conditioner compressor 8. By reducing the degree of operation of the air conditioner compressor 8, the torque of the air conditioner compressor 8 is reduced, and the load on the engine is also reduced. Therefore, the rate of decrease of the engine speed decreases.
[0031]
If the lock-up clutch 2a is engaged at the time (t2) when the rotational speed of the torque converter decreases and becomes substantially equal to the rotational speed of the engine, the engagement can be surely performed.
[0032]
By engaging the lock-up clutch 2a, the inertia of the drive wheels also acts on the engine rotation, so that it is possible to prevent the engine speed from being excessively reduced even when the fuel is cut. Therefore, it is possible to improve fuel efficiency by fuel cut during deceleration.
[0033]
As described above, in this embodiment, prior to the engagement of the lock-up clutch 2a at the time of deceleration, the load on the engine is reduced by reducing the degree of operation of the air conditioner compressor 8, so that the lock-up clutch 2a is securely engaged. Becomes possible.
[0034]
At the time of deceleration, the lock-up clutch 2a is engaged to maintain the engine speed by the inertia force of the drive wheels, so that it is possible to perform fuel cut and improve fuel efficiency.
[0035]
Next, a second embodiment will be described with reference to the flowchart of FIG.
[0036]
This embodiment is basically the same as the first embodiment, except that the supplementary load is reduced by changing the power generation voltage of the alternator 9 instead of changing the operation degree of the air conditioner compressor 8. Therefore, steps S200 to S203, and steps S205 and S206 correspond to steps S100 to S103 and steps S105 and S106 of the first embodiment. Steps S107 and S207 are synonymous in that processing for covering the correction torque amount is prohibited.
[0037]
The difference from the first embodiment is that the power generation voltage of the alternator is calculated according to the correction torque amount in step S204. The power generation voltage is calculated by the ECU 5 and a signal is input to the power generation controller (USM) 6. The USM 6 controls the power generation voltage of the alternator 9 according to the signal. Since the generated voltage variable control of the alternator 9 is known, a specific calculation method is omitted.
[0038]
The torque correction by the variable control of the alternator 9 generated voltage will be described with reference to FIG.
[0039]
When the accelerator is turned off at t1, the generated voltage is reduced, and the torque of the alternator 9 is reduced. At this time, unlike the decrease in the torque of the air conditioner compressor 8, the torque instantaneously decreases. This is because the air conditioner compressor 8 uses a refrigerant (fluid), so that a response is delayed even if a signal is input from the ECU 5 to the A / C amplifier 7, whereas a response delay is generated between the alternator 9 and the ECM 5. This is because there is no element that causes the above, and all of them can be electrically controlled.
[0040]
As described above, this embodiment has an effect that the same effect as that of the first embodiment can be obtained more quickly.
[0041]
A third embodiment will be described.
[0042]
In this embodiment, the load on the auxiliary equipment is reduced by using both the degree of operation of the air conditioner compressor 8 and the voltage generated by the alternator 9.
[0043]
FIG. 5 shows a control flow of the present embodiment. Steps S300 to S303 correspond to steps S200 to S203 of the second embodiment.
[0044]
In step S304, the load distribution and the correction rate of the air conditioner compressor 8 and the alternator 9 are determined according to the torque correction rate calculation table shown in FIG.
[0045]
The left column in FIG. 11 shows the correction torque amount calculated in step S303, which is divided into three ranges according to the magnitude of the correction torque.
[0046]
The second and third columns from the left are the torques of the air conditioner compressor 8 and the alternator 9 before the correction control, respectively.
[0047]
As a method of detecting the torque of the air conditioner compressor 8 before the correction control, there are a method of detecting with a torque sensor attached to the compressor, a method of estimating from a refrigerant discharge pressure (PD pressure), and the like.
[0048]
The method of detecting the torque of the alternator 9 before the correction control includes a method of estimating the torque from the current value detected by the current sensor, a method of estimating the engine torque by subtracting the torque of another accessory (such as the torque of the air conditioner compressor) from the engine torque, and the like. There is.
[0049]
The fourth and fifth columns from the left represent the torque correction rates of the air conditioner compressor 8 and the alternator 9, respectively. From Table 1, it can be seen that, for example, when the correction torque amount is equal to or greater than zero and less than 5 Nm and the torques of the air conditioner compressor 8 and the alternator 9 are both less than 5 Nm, the torque is not corrected.
[0050]
The basic idea of this control is to give priority to the correction by the alternator 9 first, and to compensate for the part that cannot be corrected by the alternator 9 with the correction by the air conditioner compressor 8. This is because the correction by the alternator 9 has better responsiveness as described above.
[0051]
The order of the calculation performed in step S304 is as follows. First, it is determined where the correction torque amount calculated in step S303 falls within the three ranges. Then, the alternator torque and the air conditioner compressor torque are applied. Read the numbers and determine each correction factor.
[0052]
Next, the process proceeds to step S305, where the power generation variable amount of the alternator 9 is determined based on the correction rate determined in step S304, and the process proceeds to step S306.
[0053]
In step S306, the operation degree of the air conditioner compressor 8 is determined as in step S305, and the process proceeds to step S307.
[0054]
Hereinafter, steps S307 to S309 correspond to steps S205 to S207 of the second embodiment.
[0055]
An example of the torque correction of the present embodiment (when both the alternator 9 and the air conditioner compressor 8 have non-zero correction rates) is shown in a time chart as “air conditioner + alter total torque” in FIG. The waveform is obtained by adding the waveform of the correction by the alternator 9 and the waveform of the torque correction by the air conditioner compressor 8.
[0056]
As described above, in this embodiment, in addition to the same effects as those of the first and second embodiments, the correction torque amount is covered by using both the alternator 9 and the air conditioner compressor 8, so that, for example, the power generation amount of the alternator is small, If it is not desired to lower the generated voltage for the correction of the air conditioner, it is possible to carry out detailed control in accordance with the required performance of the vehicle, for example, by increasing the sharing ratio of the air conditioner compressor 8, thereby improving the fuel efficiency.
[0057]
The fourth embodiment will be described with reference to the control flowchart of FIG.
[0058]
In the present embodiment, when the air conditioner compressor 8 and the alternator 9 cannot cover the correction torque amount of the engine required for engagement of the lock-up clutch, the engagement hydraulic pressure of the lock-up clutch 2a is increased according to the insufficient torque amount. Perform control.
[0059]
Steps S400 to S403 correspond to steps S300 to S303 of the third embodiment.
[0060]
In step S404, the total torque of the air conditioner compressor 8 and the alternator 9 is compared with the correction torque amount calculated in step S403. Here, if the correction torque amount is larger, the process proceeds to step S405. If the correction amount is smaller, the process proceeds to step S407.
[0061]
In step S405, the amount of torque (oil pressure sharing torque) to be covered by increasing the engagement oil pressure of the lock-up clutch 2a is calculated. That is, the correction torque obtained by subtracting the total torque of the air conditioner compressor 8 and the alternator 9 from the correction torque amount is added to the correction rate obtained from the table in FIG. 9 and the process proceeds to step S406. FIG. 9 is a table of the hydraulic pressure correction rate. The value obtained by subtracting the total torque of the air conditioner compressor 8 and the alternator 9 from the correction torque amount is classified into three ranges. When the value is small, the correction rate is 1.0, that is, No correction is performed. As the value increases, the correction rate also increases.
[0062]
In step S406, the engagement hydraulic pressure of the lock-up clutch 2a is increased according to the hydraulic pressure sharing torque calculated in step S405, and the flow proceeds to step S407.
[0063]
Steps S407 to S412 correspond to steps S304 to S309 of the third embodiment.
[0064]
As described above, in the present embodiment, in addition to obtaining the same effects as in the third embodiment, the lock-up is performed even when the amount of torque that can be corrected by the air conditioner compressor 8 and the alternator 9 is smaller than the corrected torque amount. By increasing the engagement hydraulic pressure of the clutch 2a, the lock-up clutch 2a can be securely engaged, and the fuel efficiency can be improved.
[0065]
It is needless to say that the present invention is not limited to the above embodiment, and various changes can be made within the scope of the technical idea described in the claims.
[Brief description of the drawings]
FIG. 1 is a diagram showing a system configuration of the present invention.
FIG. 2 is a deceleration-time lock-up clutch engagement permission determination table.
FIG. 3 is a control flowchart of the first embodiment.
FIG. 4 is a control flowchart of a second embodiment.
FIG. 5 is a control flowchart according to a third embodiment.
FIG. 6 is a control flowchart of a fourth embodiment.
FIG. 7 is a table for searching for a timer initial value.
FIG. 8 is a torque converter correction amount search table.
FIG. 9 is a table for searching a lock-up clutch engagement hydraulic pressure correction rate.
FIG. 10 is a time chart showing the control of the present invention.
FIG. 11 is a table for searching for a sharing ratio of a torque correction amount.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 3 Transmission 4 Transmission ECU
5 Control unit (ECU) (Auxiliary equipment load reduction means)
6 Power generation controller (USM)
7 Air conditioner amplifier (A / C amplifier)
8 Air conditioner compressor 9 Alternator

Claims (8)

A torque converter with a lock-up clutch connecting the engine and the automatic transmission,
Accessories driven by the rotation of the engine,
A lock-up clutch engaging means for engaging the lock-up clutch when the vehicle is decelerating;
A control device for a vehicle, comprising: an auxiliary load reduction unit configured to reduce a load on the auxiliary machine prior to engagement of the lock-up clutch during the deceleration. The control device for a vehicle according to claim 1, wherein the auxiliary device load reducing unit reduces a load on an air conditioner compressor. The control device for a vehicle according to claim 1, wherein the auxiliary load reduction unit reduces the load on the alternator. The vehicle control device according to claim 1, wherein the auxiliary load reduction unit reduces loads on both an air conditioner compressor and an alternator. 5. The vehicle control device according to claim 4, wherein the auxiliary load reduction unit distributes and reduces the loads on both the air conditioner compressor and the alternator according to the required performance of the vehicle. The said auxiliary equipment load reduction means does not reduce auxiliary equipment load, when the load of an air conditioner compressor and an alternator satisfy | fills predetermined conditions, The auxiliary equipment load as described in any one of Claims 1-5 characterized by the above-mentioned. Vehicle control device. The control device for a vehicle according to any one of claims 4 to 6, wherein the auxiliary load reduction unit performs load reduction of the alternator first, and then reduces load of the air conditioner compressor. The lock-up clutch fastening unit increases the engagement hydraulic pressure of the lock-up clutch when the amount of reduction in the auxiliary load by the auxiliary load reduction unit is less than the correction load of the engine required for engagement of the lock-up clutch. The control device for a vehicle according to any one of claims 1 to 8, wherein:

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