JPH01176838A - Automatic speed shift control device for vehicle - Google Patents

Abstract

PURPOSE:To aim at enhancing the feeling of deceleration by shifting down an automatic transmission compulsorily by at least one stage when the rotational speed of an engine exceeds a fuel supply cut releasing speed by a predetermined amount and a brake operation is detected. CONSTITUTION:In a control circuit 7, a computing means 11 calculate a basic fuel injection amount in accordance with an intake-air amount detected by an air flows 5, and a fuel control means 13 drives a fuel injection valve 3. Further, when a judging means 12 determines a fuel cut zone in accordance with a throttle opening degree and an engine rotational speed detected by sensors 8, 9, the supply of fuel is cut off and a control means 14 compulsorily fastens a lock-up clutch. In this fuel cut operation range, when a judging means 15 detects an engine rotational speed exceeding a critical engine rotational speed which is set to be higher than the fuel supply cut-off speed by a predetermined amount while a judging means 16 detects a brake operation, a judging means 18 and a speed stage control means 17 compulsorily shift down the transmission by at least one stage.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an automatic transmission control device for a vehicle, and more particularly to an automatic transmission control for a vehicle that improves fuel efficiency and deceleration feeling. It is related to the device.

Prior Art When the vehicle is coasting with the accelerator pedal released and the engine speed is above a predetermined value, power from the engine is not required, so a fuel cut signal is generated in such a driving state. Equipped with fuel cut determination means, when a fuel cut signal is output,
2. Description of the Related Art An engine control device is known that prevents the discharge of unburned gas and improves fuel efficiency by controlling the supply of fuel to the engine to be cut. In this control device, by limiting the operating range in which fuel supply is cut to a predetermined engine speed at which the engine can be restarted (hereinafter referred to as fuel cut release speed), when fuel supply is restarted, However, in vehicles where engine power is transmitted to the vehicle drive wheels through an automatic transmission, the automatic transmission has a torque converter in the power drive system, which prevents the engine from stopping. Since it is not possible to directly connect the drive wheels to the
The reverse driving force transmitted from the drive wheels to the engine is small, and when the accelerator pedal is released, the engine speed drops rapidly compared to a manual transmission vehicle. In vehicles equipped with automatic transmissions, the engine is likely to stop even if the fuel supply is restarted after sudden deceleration in driving conditions where engine braking is applied and the fuel supply is resumed. The engine speed at which the fuel supply must be restarted has to be set higher than that of a manual transmission vehicle, and as a result, there was a problem in that it was not possible to fully achieve the effect of improving fuel efficiency by cutting the fuel supply. .

Japanese Patent Publication No. 60-38584 discloses, in order to solve the problem with such an engine control device, that when the engine speed is higher than the fuel cut release speed during coasting (coasting) driving with the accelerator pedal released, , detects brake operation in a vehicle automatic transmission control device that includes a fuel cut determination means that generates a fuel cut signal, and controls to cut fuel supply to the engine when the fuel cut signal is output. It is equipped with a brake sensor that generates a brake activation signal, and when a fuel cut signal and a brake activation signal are generated and output,
An automatic transmission control device is proposed that includes a downshift command means for generating and outputting a downshift signal, and is configured to forcibly downshift the automatic transmission using the downshift signal. According to this automatic transmission control device, the automatic transmission is forcibly downshifted when the fuel supply is cut, when the driver is in the driving range, and when the brakes are applied when the driver desires a relatively large deceleration. increases, and the time it takes for the engine speed to drop to the fuel cut release speed becomes longer, making it possible to expand the fuel cut operation range. Since downshifting is prohibited when a large deceleration is not desired, it is possible to obtain the effect that in such a case, the engine brake will not be applied too much due to downshifting, and the driver will not be shocked.

Problems to be Solved by the Invention However, in the automatic transmission control device disclosed in Japanese Patent Publication No. 60-38584, the engine speed decreases until the downshift is completed, and the fuel cut is canceled. Since fuel injection is restarted when the rotational speed is reached, the downshift and the restart of fuel injection overlap,
There was a problem with the occurrence of shock.

OBJECTS OF THE INVENTION An object of the present invention is to provide a control device for an automatic transmission that improves fuel efficiency and deceleration feeling.

Structure of the Invention The object of the present invention is to provide a first detection means for detecting that the engine rotation speed or the rotation speed corresponding thereto is higher than a reference value set by a predetermined amount higher than the fuel cut release rotation speed; a second detection means for detecting the first detection means;
This is achieved by providing a downshift means that receives the outputs of the detection means and the second detection means and forcibly shifts down the automatic transmission by at least one gear.

In a preferred embodiment of the present invention, the predetermined amount is
It is set to a value corresponding to the amount of decrease in engine speed within the time required for forcibly downshifting.

In another preferred embodiment of the present invention, the predetermined amount is set to be larger as the deceleration of the vehicle at the time of output from the second detection means is larger.

EXAMPLES Hereinafter, examples of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is an overall schematic diagram of an engine including an automatic transmission control device according to an embodiment of the present invention.

In FIG. 1, an intake passage 2 is connected to an engine 1, and in the intake passage 2, an injector 3, a throttle valve 4, and an air flow meter 5 are arranged toward the upstream side.
are provided for each. Also, in engine 1,
An automatic transmission 6 is coupled thereto, and the automatic transmission 6 has a plurality of shift solenoids and lock-up solenoids (not shown), and a hydraulic circuit (not shown) is switched by a combination of turning on and off the shift solenoids. By selectively engaging a plurality of hydraulic engagement elements, the transmission mechanism is configured to switch to a plurality of gear stages, and by turning on and off a lock-up solenoid, a torque converter (not shown) is activated. The lock-up clutch is engaged or released.

Further, a control unit 7 is provided, which includes a throttle valve opening signal detected by a throttle valve opening sensor 8, an intake air amount detection signal detected by an air flow meter 5, an engine rotation speed sensor 9 such as a crank, angle sensor, etc. The engine speed detection signal detected by the brake switch 10 and the brake activation signal detected by the brake switch 10 are input.

The control unit 7 calculates the fuel injection amount based on these input signals, calculates the fuel injection amount signal to the fuel injection valve 3, calculates the gear position, sends the gear position control signal to the gear change solenoid, and also outputs the lock-up signal. It determines whether or not it is in the state, and outputs a lock-up control signal to each lock-up solenoid.

12H1 indicates a block diagram in the control unit 7, and the control unit 7 is
A basic fuel injection amount calculation means 11 receives the intake air amount detection signal detected by the air flow meter 5 and calculates the basic fuel injection amount, and the throttle valve opening signal and the engine rotation speed sensor are detected by the throttle valve opening sensor 8. Fuel cut zone determination means 12) receives the output signals from the basic fuel injection amount calculation means 11 and the fuel cut zone determination means 12, which receives the engine rotational speed detection signal detected by 9 and determines whether or not it is in the fuel cut operation region. The fuel control means 13 generates a fuel control signal and outputs it to the fuel injection valve 3, and receives the output signal from the fuel cut zone determination means 12. A lock-up control means 14 that outputs a control signal to a lock-up solenoid.
, calculates the engine speed Nc at which the downshift is performed in an operating range of engine speeds higher than that, and determines whether the detected value of the engine speed input from the engine speed sensor 9 is greater than the critical engine speed Nc. A critical engine rotation speed determining means 15 receives a brake activation signal from the brake switch 10 and determines whether the brake switch 10 is turned on or not and whether it is in the ON state. A fuel cutoff is performed. Zone determining means 12) Upon receiving the output signals from the critical engine speed determining means 15 and the brake operation determining means 16, the engine speed is determined to be the critical engine speed Nc in the fuel cut operation region.
a shift-down determination means 18 and a shift-down determination means for generating a shift-down signal for forcibly performing a down-shift only when the brake is activated and outputting the generated shift-down signal to the gear position control means 17; The gear shift control means 17 receives an output signal from the shift gear control means 17 and outputs a gear shift control signal to a shift solenoid. Although not shown in FIG. 2, the lockup control means 14 receives a signal from a means for making a normal lockup determination, and the gear position control means 17 also receives a signal from a means for making a normal lockup determination. A signal from a signal for determining the state is input.

FIG. 3 is a flowchart showing a method of speed change control by the automatic transmission control device according to the present embodiment.

In FIG. 3, first, the throttle valve opening sensor 8
The throttle valve opening signal detected by , the engine rotational speed detection signal detected by engine rotational speed sensor 9 , and the intake air amount detection signal detected by air flow meter 5 are manually input and read into control unit 8 .

Next, the basic fuel injection amount is calculated by the basic fuel injection amount calculating means 11 based on the intake air amount detection signal from the air flow meter 5, and is output to the fuel control means 13.

Further, based on the throttle valve opening signal from the throttle valve opening sensor 8, the fuel cut zone determining means 12 determines whether or not the vehicle is in a deceleration state.

As a result, when it is determined that the deceleration state is not present, the fuel cut zone determination means 12 outputs a fuel injection signal to the fuel control means 13, and the fuel control means 13 receives the basic fuel injection amount inputted from the basic fuel injection amount calculation means 11. A predetermined correction is made to the fuel injection amount as necessary, a fuel injection amount signal is output to the fuel injection valve 3, and the fuel is injected from the fuel injection valve 3.

On the other hand, when it is determined that the vehicle is in a deceleration state, the fuel cut zone determination means 12 further determines the fuel cut zone determination map based on the engine rotational speed detection signal and that has been experimentally determined and stored in advance. Determine whether or not it is in the fuel cut operation region. Figure 4 shows an example of a fuel cut zone determination map, where the vertical axis shows the throttle valve opening, the horizontal axis shows the engine speed, and the line A
indicates the fuel cut rotation speed Nf at which the fuel cut is canceled and fuel injection is restarted. The fuel cut operation region is indicated by diagonal lines.

As a result of the determination, when it is determined that the operation is not in the fuel cut operation region, the fuel cut zone determination means 12 outputs a fuel injection signal to the fuel control means 13, and the fuel control means 13 outputs a fuel injection signal from the basic fuel injection amount calculation means 11. A predetermined correction is added to the input basic fuel injection amount as necessary, a fuel injection amount signal is output to the fuel injection valve 3, and fuel is injected from the fuel injection valve 3.

On the other hand, when it is determined that the vehicle is in the fuel cut operation region, the fuel cut zone determination means 12 outputs a fuel cut determination signal to the fuel control means 13, the lockup control means 14, and the shift down determination means 18.

When the fuel cut determination signal is input from the fuel cut zone determination means 12, the fuel control means 13 transmits the fuel cut signal to the fuel injection valve regardless of the basic fuel injection amount input from the basic fuel injection amount calculation means 11. 3 to prohibit fuel injection from the fuel injection valve 3.

Further, when a fuel cut determination signal is input from the fuel cut zone determination means 12, the lockup control means 14 outputs a lockup control signal for forcibly locking up the engine in order to apply the engine brake more effectively. It outputs to the solenoid and locks up.

Furthermore, based on the brake activation signal from the brake switch, the brake activation determination means 16 determines whether or not the brake has been activated. While the brake is in operation,
A brake activation signal is output to the downshift determining means 18.

When the brake operation start signal is input, the critical engine speed determination means 15 calculates the deceleration at that point by differentiating the engine speed detection signal from the engine speed sensor 10, and calculates the deceleration at that time by differentiating the engine speed detection signal from the engine speed sensor 10. Based on the deceleration, a critical engine rotational speed Nc for performing a downshift is calculated in an operating range of engine rotational speeds higher than the deceleration. More specifically, the critical engine rotational speed determination means 15 determines a value a corresponding to the deceleration according to the stored addition value determination map, and determines the critical engine rotational speed Nc when the fuel cut is canceled to restart fuel injection. It is calculated by adding this additional value a to the value of the rotation speed Nf. That is, the critical engine rotational speed Nc is calculated using the following equation. (The critical engine speed Nc calculated in this way is shown on line b in Fig. 4.
It is shown as. ) Nc=Nf+a FIG. 5 shows an example of an additional value determination map for determining the additional value a. In this example, the additional value a is set to increase in proportion to the deceleration. There is. In this way, the critical engine speed Nc at which downshifting is performed in the operating range of engine speeds higher than that is set to a value higher by the additional value a than the fuel cut release speed Nf at which fuel injection is restarted. Since it is set to , the engine speed decreases due to the fuel cut, and the downshift is executed before the fuel cut is canceled and fuel injection is restarted.
It is possible to prevent a shock from occurring due to temporal overlap between restart of fuel injection and downshift. Furthermore, in this embodiment, the larger the deceleration, the larger the additional value a, that is, the difference between the critical engine speed Nc and the fuel cut release speed Nf is set to become larger. Even when the engine speed decreases rapidly in an operating state where the deceleration is large, it is possible to effectively prevent the possibility that the downshift and the restart of fuel injection overlap in time. In this embodiment, the value of the additional value a is determined based on the deceleration at the time when the brake operation start signal is input, that is, when the brake switch 10 is turned on, and is kept constant during downshift control. There is. Critical engine speed determination means 1
5 outputs the value of the critical engine rotational speed Nc thus calculated to the downshift determining means 18.

The shift down determination means 18 is the brake operation determination means 1.
6, it is determined whether or not the brake is in operation based on whether or not a brake operation signal is input.

As a result, when it is determined that the brakes are not operating, if a downshift is performed, engine braking may be too effective and the driver may feel uncomfortable, so a downshift signal is not generated, and the brakes are not activated. When it is determined that the engine is operating, it is further determined whether the engine rotation speed N is equal to or higher than the critical engine rotation speed Nc.

As a result, the engine speed N becomes the critical engine speed N
If it is determined that it is less than c, if a downshift is performed, the cancellation of the fuel cut, that is, the restart of fuel injection, and the downshift will overlap in time, causing a shock, so the downshift determining means 18 A downshift signal is not generated, and on the other hand, when it is determined that the engine speed N is higher than the critical engine speed Nc, a downshift signal is output to the gear position control means 17.

When a shift down signal is input from the shift down determining means 18, the gear position control means 17 determines the gear position n at that time, and applies the gear position control signal to the gear position so that the gear position becomes n-1. The gear shift solenoid is selected so that the output is output to the solenoid and a predetermined downshift is performed.

Thereafter, the fuel cut zone determining means 12 determines whether the engine rotation speed N is equal to or lower than the fuel cut release rotation speed Nf, and when it is determined that the engine rotation speed N is equal to or lower than the fuel cut release rotation speed Nf, A fuel cut release signal is output to the lockup control means 14 and the fuel control means 13, a lockup release signal is output to the lockup solenoid, the lockup is released, and a fuel injection amount signal is output to the fuel control means 13. 13
The fuel is outputted to the fuel injection valve 3, and the fuel is injected from the fuel injection valve 3. On the other hand, when the engine rotational speed N exceeds the fuel cut release rotational speed Nf, the same control is resumed without locking, releasing, or fuel injection.

As described above, according to the present embodiment, the critical engine rotation speed Nc at which a downshift is executed at a higher engine rotation speed is changed to the fuel cut release rotation speed Nf at which fuel injection is resumed.
Since it is set to a higher value by the additional value a,
The engine speed decreases due to operation in a fuel cut state, and the downshift is completed before fuel injection is restarted, so the shock is caused by the overlap in time between the restart of fuel injection and the downshift. This makes it possible to prevent the occurrence of Furthermore, in this embodiment, the larger the deceleration, the larger the additional value a, that is, the larger the difference between the critical engine rotation speed Nc and the fuel cut release rotation speed Nf. Even when the engine speed decreases rapidly in an operating state where the engine speed is large, it is possible to effectively prevent the possibility that the downshift and the restart of fuel injection overlap in time.

The present invention is not limited to the above-mentioned examples, and various modifications can be made within the scope of the invention described in the claims, and these are also included within the scope of the present invention. It goes without saying that there is.

For example, in the above embodiment, the control unit 7 includes a basic fuel injection amount calculation means 11, a fuel cut zone determination means 12), a fuel control means 13, a lockup control means 14, a critical engine speed determination means 15, and a brake operation determination means. Although means 16, gear position control means 17, and downshift determining means 18 are provided, these means do not need to be physical devices, and the control unit 8 may be configured by, for example, a microcomputer or the like. The scope of the present invention also includes a case where these functions are implemented as a whole using software.

Therefore, the connections between the various means in the control unit 7 and the input/output of signals in the above embodiment are not particularly limited, and there is no problem in making changes as long as these functions are realized as a whole. .

Effects of the Invention According to the present invention, it is possible to obtain a control device for an automatic transmission that improves fuel efficiency and deceleration feeling.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram of an engine including a control device for an automatic transmission according to an embodiment of the present invention, FIG. 2 is a block diagram inside the control unit, and FIG. 3 is a diagram according to an embodiment of the present invention. 3 is a flowchart showing a shift control method in an automatic transmission control device. FIG. 4 is a graph showing an example of a fuel cut zone determination map, and FIG. 5 is a graph showing an example of an addition value determination map. DESCRIPTION OF SYMBOLS 1... Engine, 2... Intake passage, 3... Fuel injection valve, 4-1-throttle valve, 5... Air flow meter, 6... Automatic transmission, 7... Control unit , 8... Throttle valve opening sensor, 9... Engine rotation speed sensor, 10... Brake switch, 11... Basic fuel injection amount calculation means, 12... Fuel cut zone determination means, 13. ...Fuel control means, 14.Lockup control means, 15.Critical engine speed determination means, 16.Brake operation determination means, 17.Gear position control means, 18.Shift down determination. means. The outside of the tongue is dark and dark

Claims (2)

[Claims] (1) Automation of vehicles equipped with an engine configured to cut fuel supply in a predetermined operating range and an automatic transmission that automatically shifts between multiple gears receiving the driving force of the engine. In the transmission control device, a first detection means detects that the engine rotation speed or the rotation speed corresponding thereto is higher than a reference value set a predetermined amount higher than the rotation speed at which the fuel supply cut is canceled; and a brake operation. The automatic transmission is characterized by comprising: a second detection means for detecting; and a downshift means for forcibly downshifting the automatic transmission by at least one gear in response to the outputs of the first detection means and the second detection means. Vehicle automatic transmission control device. (2) In the automatic transmission control device for a vehicle according to claim 1, the predetermined amount is a value corresponding to the amount of decrease in engine speed within the time required for forcibly downshifting. A control device for an automatic transmission, characterized in that: (3) In the automatic transmission control device for a vehicle according to claim 1, the predetermined amount is
A control device for an automatic transmission, characterized in that the larger the deceleration of the vehicle at the time of output from the second detection means, the larger the setting is.