JPH0514133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic transmission control device for an electronically controlled transmission.

(Prior art) Vehicles with internal combustion engines, such as automobiles,
In order to effectively utilize the output of the internal combustion engine, a transmission is provided between the internal combustion engine and the drive wheels. When the vehicle travels at low speeds, the gear ratio is increased to increase the rotational speed of the internal combustion engine, and when the vehicle travels at high speeds, the gear ratio is decreased.

Nowadays, automatic transmission devices have been proposed that automatically change gears of a transmission using an actuator whose operation is controlled by an electronic control device. This device has, for example, a select actuator that can be displaced in the Y direction and a shift actuator that can be displaced in the X direction, and the continuous operation of these actuators automatically selects and switches gears of the transmission. It is configured to be implemented.

The computer-based electronic control device is provided with a storage device that stores data (shift map) that stores the gear positions of the transmission corresponding to the vehicle speed and the amount of depression of the accelerator pedal. While the vehicle is driving, the electronic control unit constantly detects the vehicle speed and the amount of accelerator pedal depression, searches the shift map based on this data to find the optimal gear, and then activates the select actuator according to a command from the electronic control unit. The actuator and shift actuator are alternately driven to switch the gear ratio of the transmission to the optimum one.

In other words, in such conventional electronic control devices, the shift point is determined based on an automatic shift shift map that is determined and set in advance from the vehicle speed and the accelerator opening, regardless of fuel consumption.

(Problems with the prior art) However, when shifting gears based on such a shift map, as described above, the gear stage is automatically selected only from the vehicle speed and the accelerator opening.
It is not designed to achieve driving at the gear position that minimizes fuel consumption. In other words, even if the vehicle is driven in a different, lower speed range, the accelerator opening remains the same and the fuel consumption rate remains high. This case applies, for example.

Of course, in order to solve such problems, we emphasize output,
Electronically controlled transmission systems are also available that have two types of maps: a power mode for when fuel efficiency is not a concern and an economy mode for improving fuel efficiency.

However, in this case, instructions are only given to the fuel efficiency indicator etc. based on the equal fuel consumption map of the engine, and if the driver does not follow these instructions, there is a drawback that the fuel efficiency cannot be improved. Ta.

(Purpose of the Invention) The present invention has been made by focusing on the above-mentioned problems of the conventional technology.The equal fuel consumption curve of the engine is stored in ROM, etc., and the fuel consumption when the vehicle is running is calculated. An object of the present invention is to provide a speed change control method for an electronically controlled transmission that automatically changes gears to a gear position that results in fuel efficiency.

(Summary of the Invention) In order to achieve the above object, an automatic transmission control device for an electronically controlled transmission that automatically switches gears by an actuator whose operation is controlled by an electronic control device includes: A detection means for detecting a quasi-steady running state in which the acceleration change of the vehicle is gradual, a search means for searching for the fuel consumption of the engine at the current gear, a means for calculating the engine torque at another gear, Means for determining the engine torque margin of a gear with respect to other gears, means for reading fuel consumption in other gears with torque margin, and means for determining the gear with the smallest fuel consumption. This is an automatic transmission control device for an electronically controlled transmission.

(Example) Examples of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a block diagram of a speed change control circuit for implementing the present invention. In the figure, 1 is an accelerator opening sensor, and 2 is an accelerator opening sensor that detects whether it is a sudden acceleration such as when starting after the engine has started or a kickdown, or whether the change in acceleration is in a gradual quasi-stable state. The degree change sensor 3 is an acceleration detection sensor, and each of these sensors 1, 2,
3 outputs are input to the controller 4, and the accelerator opening degree A/P and the accelerator opening change amount ΔA/P are input to the controller 4.
If both exceed a certain value, or if the acceleration △V/P exceeds a certain value, control in E mode, which will be described later, will not be performed, and the optimum speed change will be performed from the memory 9 that stores normal automatic speed change map data. Data is output, and based on this output, the shift actuators 5, 6,
7, 8 in one direction, R, L,
The vehicle is operated in a normal automatic transmission mode by selecting a transmission gear having a larger gear ratio among the 2nd, 3rd, 4th, 5th, and 6th gears.

On the other hand, unlike the above, when the acceleration change of the vehicle is gradual and the accelerator opening is small and the acceleration is small, that is, when driving in a quasi-steady state, the economy mode (called E mode) where the fuel consumption is the minimum is used. ) to drive a vehicle. Further, the shaft average pressure Pme corresponding to the engine torque is read out from the memory 10 storing Pme map data, and if the read Pme value is smaller than a certain value, it is determined that a load is directly applied to the engine itself. Holds the current gear. In this case, the engine brake and the exhaust brake are applied, and when the vehicle speed reaches a predetermined speed or less in the current gear during deceleration, each actuator 5 to 8 is controlled so as to further shift to a lower gear.

In the E mode control state, the engine torque Pmei in other gears is calculated. this
Pmei is calculated from the equal horsepower line for gears other than the current gear.

The controller 4 compares and calculates how much the Pmei obtained in this way is with respect to the maximum value of Pme of the current gear, that is, whether there is a margin in the engine torque.If it is determined that there is a margin, this The fuel consumption SFCi in other gears when
The SFC data map is read out from the memory 11, and the gear stage that provides the minimum fuel consumption at this time is selected, and one of the actuators 5 to 8 is selectively controlled.

That is, in the embodiment, during semi-steady running, the engine torque and fuel consumption are calculated, and automatic gear shifting is performed to the gear that provides the lowest fuel consumption.

Furthermore, when starting or downhill, the vehicle speed is controlled according to the normal automatic transmission diagram, so the desired large acceleration is obtained, making it possible to start and overtake smoothly.

Next, the speed change control method of the present invention will be explained with reference to the flow chart of FIG.

First, in step a, the controller of the electronic control unit determines whether the vehicle is in a start state (start mode) or in a normal driving state, that is, whether the vehicle has started traveling. When the mode is confirmed, E
Shifting to normal driving control, which is not a mode, the automatic shift map of vehicle speed - accelerator opening is searched (step b), the optimum gear position for achieving a predetermined vehicle speed according to the accelerator opening is found (step c), and the electronic control unit The controller sets the gear ratio using a shift actuator, etc.

On the other hand, while the vehicle is running normally, there are cases where the vehicle is overtaking or climbing a slope, and it is desired to perform a so-called kickdown operation in which the accelerator pedal is fully depressed. In this kick-down operation, the accelerator opening A/P is a constant value (different for each gear).
It is determined whether or not it is greater than or equal to (step d), and furthermore, the amount of change in accelerator opening in a time of 25 msec △A/
It is determined whether P is also greater than a certain value (step e),
If the accelerator opening degree A/P and the change amount ΔA/P in the accelerator opening degree are equal to or greater than a certain value, shift control (normal control) based on the automatic shift map is performed (step b).

Next, the accelerator opening A/P and its change amount △
Even if it is determined that A/P is below a certain value, the amount of change in vehicle speed △V/△ in a period of 25 msec
If T exceeds a certain value, it is determined that the acceleration state is close to kickdown, as in steps d and e (step f), and shift control is performed based on the automatic shift map. In this case, a constant value to be compared with the amount of change ΔV/ΔT in vehicle speed is searched using the map shown in FIG.

If ΔV/ΔT is determined to be below a certain value, the vehicle is in a quasi-steady state in which acceleration changes are gradual.

In such a quasi-steady state, the engine torque, that is, the shaft average pressure Pme of the output shaft is read from the Pme search map in FIG. 4 (step g), and when it is determined that this shaft average pressure Pme is not greater than a certain value. (step h), it is determined that the engine brake or exhaust brake is in operation,
Hold the current gear (step i).

Here, when it is determined that the shaft average pressure Pme is equal to or higher than a certain value, the fuel consumption amount SFC of the current gear is read (step j). This fuel consumption amount SFC is determined by the reciprocal of thermal efficiency α. Note that this fuel consumption amount SFC is searched using the SFC data map shown in FIG.

Next, the torque Pmei of the other gears is obtained from the search data map of the current torque Pme shown in Fig. 4 (step k), and the maximum value of this Pmei and this Pme is determined.
It is checked whether the difference from Pme ^max is larger than a certain value, that is, the torque margin for other gears is checked (step 1).Here, Pme ^max -
When Pmei is greater than a certain value, the fuel consumption SFCi of a gear other than the current gear is read (step m). The values of Pmei for other gears can be determined from the equal horsepower line X passing through the point Pme of the current gear using the following equation, as shown in FIG.

Pmei=Pme・N/Ni Here, N and Ni are the engine speeds in the current gear and other gears, and Ni is determined by multiplying the vehicle speed or the current engine speed by the gear ratio.

Next, in step n, a search is made for the minimum fuel consumption in another gear, and the gear is shifted to the gear with the lowest fuel consumption (step o).

In this way, when the vehicle is running in a quasi-steady state, the engine torque and fuel consumption are detected for each gear, and if the engine torque has a surplus, the fuel consumption is detected for the gear with the surplus. Then, the optimum gear stage is determined to minimize this fuel consumption.

(Effects of the Invention) As described in detail above, according to the present invention, while monitoring the engine torque and fuel consumption in a quasi-steady running state, the combination of engine speed and transmission gear is adjusted. In addition to being able to select and shift gears to achieve the lowest fuel efficiency, the system also maintains transient characteristics that follow the normal automatic shift map when starting or kicking down, providing smooth acceleration.

[Brief explanation of the drawing]

Figure 1 is a block connection diagram of the automatic transmission control system for implementing the present invention, Figure 2 is a flow chart, Figure 3 is a vehicle speed acceleration characteristic diagram, Figure 4 is a search data map of engine torque, and Figure 5 is fuel consumption. The quantity data map, Figure 6, is an equal horsepower diagram. 4... Controller, 5, 6, 7, 8... Actuator, 9... Automatic transmission map, 10... Engine torque map memory, 11... Fuel consumption data map memory.

Claims (1)

[Claims] 1. In an automatic transmission control device for an electronically controlled transmission that automatically switches gears using an actuator whose operation is controlled by an electronic control device, a quasi-steady running state in which the acceleration change of the vehicle is gradual is detected. a detection means for searching for the fuel consumption of the engine at the current gear;
A means for calculating the engine torque in other gears, a means for determining the engine torque margin of the current gear with respect to other gears, and a means for reading out the fuel consumption in other gears with torque margin. means and
An automatic transmission control device for an electronically controlled transmission, comprising means for determining a gear position with the lowest fuel consumption.