JPH05149155A - Shift shock reducing device of automatic transmission for power train - Google Patents

Abstract

PURPOSE:To reduce the generation of a shift shock through switching of engine output characteristics by detecting the shift of an automatic transmission by a speed change detecting means, and varying engine output characteristics so that the direction of an engine output may be changed in a direction, in which the generation of the shift shock is reduced, by means of an output characteristics varying means. CONSTITUTION:It is checked by an engine controller 12 whether a shift command is outputted to a control valve 11 by means of a transmission controller 13. When it is discriminated that a shift command is effected, it is checked whether a transmission under an up shift or a down shift. During an up shift, a shift to a P-cam is executed so that an engine output is reduced and during a down shift, a shift to an H-cam is executed so that the engine output is increased. As noted above, since engine output characteristics are varied in a direction in which the generation of a shift shock is reduced, during a shift, engine output characteristics are not switched so that the generation of a shift shock is increased and the generation of a shift shock can be reliably reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift shock reducing device for an automatic transmission in a power train in which a variable output characteristic engine and the automatic transmission are connected in tandem.

[0002]

2. Description of the Related Art As an output characteristic variable engine, for example, as described in Japanese Patent Laid-Open No. 3-111610, the output characteristic with respect to the throttle opening is switched by not using only one type of intake and exhaust valves of the engine but by properly using a plurality of cams. There is known a so-called variable valve type engine which is adapted to obtain the above.

This engine has three kinds of cams for each intake and exhaust valve. These cams, that is, the fuel economy cams for which the fuel economy is emphasized for partial engine load as shown in FIG. P-cam), a low-speed cam useful at low rotation (hereinafter referred to as L-cam), and a high-speed cam useful at high rotation (hereinafter referred to as H-cam) based on engine drive load and engine speed. It is used properly to match the driving conditions of. By selectively using this, the engine can switch the output characteristics between when the P cam is used, when the L cam is used, and when the H cam is used, as shown in FIG. 8, which shows the output shaft torque characteristics when the throttle opening is fully opened. ..

On the other hand, the automatic transmission has, for example, as shown in the RE4R01A type automatic transmission which the applicant of the present application is developing and using (see the same maintenance manual), a suitable gear position that matches the current operating condition from the throttle opening and the vehicle speed. Determined, by the selective hydraulic operation of various friction elements (clutch, brake), automatically select the appropriate gear stage,
By changing the friction element that operates when the operating state changes, the gear is shifted to another suitable gear.

[0005]

By the way, in the power train in which the variable output characteristic engine and the automatic transmission are tandem-coupled as represented by these, switching of the engine output characteristic occurs at the same time as the shift of the automatic transmission. However, in this case, if the change in the engine output shaft torque due to the switching of the output characteristics is in the direction of increasing the shift shock of the automatic transmission, the commercial value of the power train is significantly reduced. Further, even if such shift and engine output characteristic switching do not occur at the same time, it is necessary to minimize shift shock of the automatic transmission.

An object of the present invention is to solve the above-mentioned problem by switching the engine output characteristic so that the engine output torque changes in the direction in which the shift shock is reduced during the shift of the automatic transmission.

[0007]

To this end, the present invention, as shown in the concept of FIG. 1, uses a variable output characteristic engine for switching and using a plurality of output characteristics with respect to a throttle opening, and a switching use for a plurality of shift speeds. In a power train that is tandem-coupled with an automatic transmission, shift detecting means for detecting a shift of the shift speed by the automatic transmission, and the output of the engine in the direction of reducing shift shock when the shift is detected by the means. And an output characteristic changing means for changing the engine output characteristic so as to change.

[0008]

The engine is operated in accordance with the selected output characteristic, and the power from this point is output by the automatic transmission with a gear ratio changed in accordance with the selected gear. On this occasion,
When the shift detecting means detects that the automatic transmission is shifting, the output characteristic changing means changes the output characteristic of the engine,
The shift shock is reduced by the change in the engine output accompanying this.

Therefore, during the shift of the automatic transmission, the output characteristics of the engine do not switch so as to increase the shift shock, and the shift shock of the automatic transmission can be reliably reduced.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows an embodiment of the shift shock reducing device of the present invention, in which 1 is an engine, 2 is an automatic transmission, and the device of the present embodiment surely reduces the shift shock of the automatic transmission in a power train which is a tandem connection of these. It shall be.

The engine 1 burns the injected fuel with the air sucked from the air cleaner 3 through the throttle valve 4, inputs the output thus obtained into the automatic transmission 2, and outputs the combustion exhaust gas from the exhaust pipe 5 to the outside. To release. By the way, the engine 1 is assumed to be electronically controlled via the throttle actuator 7 without mechanically connecting the throttle valve 4 to the accelerator pedal 6 operated by the driver, and the intake / exhaust described above is performed in synchronization with the engine rotation. The intake / exhaust valve for opening the intake / exhaust valve is as described above with reference to FIGS.
A variable valve as described in Japanese Patent No. 610 is used, and the three types of cams are switched by a cam switching mechanism 9 that responds to the cam switching control valve 8.

The automatic transmission 2 shifts the rotational power from the engine 1 at a gear ratio corresponding to the selected shift speed and transmits it to the output shaft 10 for driving the wheels of the vehicle, for example. As described in "RE4R01A Automatic Transmission Maintenance Manual" issued by Co., Ltd., the shift control is electronically controlled through the control valve 11.

The engine controller 12 controls the opening of the throttle valve 4 via the throttle actuator 7 in the engine 1 (control command TVO), the cam switching control via the control valve 8 (control command CAM), and other engine controls. The transmission control (control command S) via the control valve 11 of the automatic transmission 2 and the control of other automatic transmissions are performed by the transmission controller 13, and information is mutually exchanged between the controllers 12 and 13. It fits. For these controls, information such as the engine speed Ne is input to the controller 12 from the engine 1 and a signal from an accelerator stroke sensor 14 that detects the depression amount AST of the accelerator pedal 6 is input to the controller 12, and the transmission is also transmitted. The controller 13 stores automatic transmission information such as the transmission output speed (vehicle speed V) in the automatic transmission 2.
Enter from.

The engine controller 12 executes the control program of FIG. 3 while receiving the information from the transmission controller 13 to execute the engine output characteristic switching control (cam switching control) for mitigating the shift shock, which is the object of the present invention. And That is, first, in steps 21 and 22, the accelerator stroke AST and the vehicle speed V are read, and in the next step 23, a suitable gear position that matches the driving state based on the preset two-dimensional map of the accelerator stroke AST and the vehicle speed V in FIG. And a combination of suitable cams (the number at the beginning of each area indicates the gear and the code at the back indicates the cam)
Ask for.

The preferred gear stage is commanded to the transmission controller 13, and this controller uses the signal S through the control valve 11 to obtain the gear stage.
Shift control.

In the next step 24, it is checked whether or not the transmission controller 13 has output a shift command to the control valve 11 due to the difference between the selected shift speed and the preferred shift speed. If there is no gear change command, step 25 is skipped, and control is passed to step 28 via steps 26 and 27.
Then, the signal CAM is set to the optimum cam obtained in step 23, and the switching to the optimum cam is immediately executed via the control valve 8 and the switching mechanism 9.

However, if it is determined in step 24 that there is a gear shift command, the elapsed time from the gear shift command instant T0 (see FIGS. 5 and 6) is measured in step 25 which is executed only once when this gear shift command is issued. The timer TM for resetting is reset to 0, and it is checked in steps 26 and 27 whether the upshift or downshift is in progress.

During the upshift gear shifting, while it is determined in step 29 that the timer TM indicates the time T1 to T2 in FIG.
At 0, switching to the P cam is performed to reduce the engine output for reducing the upshift shift shock, and at other times, at step 31, switching to the optimum cam (H cam in FIG. 5) is performed. As a result, as shown in FIG. 5, the engine output is reduced by switching to the P-cam between T1 and T2. If this is not executed, the step of the transmission output torque becomes large as ΔTQ2.
This step difference can be made smaller as ΔTQ1, and the upshift shift shock can be reliably reduced. It should be noted that, until the timer TM reaches the instant T3 at which the gear shift ends in FIG.
Keep M stepping forward to enable the above action.

On the other hand, during downshift gear shifting, step 3
While it is determined in step 4 that the timer TM indicates the time T4 to T5 in FIG. 6 in which gear shift shock mitigation measures should be taken, in step 35, switching to the H cam is performed in order to increase the engine output for mitigating downshift gear shift shock. Run and
Otherwise, in step 36, switching to the optimum cam (P cam in FIG. 6) is executed. As a result, as shown in FIG. 6, the engine output is increased by switching to the H-cam between T4 and T5, and if this is not executed, the step of the transmission output torque becomes large as ΔTQ4. It can be made small like TQ3, and the downshift shift shock can be reliably reduced. The timer TM continues to advance in step 38 until the timer TM reaches the shift end instant T6 in FIG. 6 to enable the above operation.

In the above example, the timing at which the engine output characteristic switching control for gear shift shock reduction is to be executed is determined based on the management of the elapsed time from the gear shift command instant T0. While the effective gear ratio represented by the ratio is a value G2 to G3 between the gear ratios G1 and G4 shown in FIG. 5 (during an upshift), or FIG.
While values G6 to G7 between the gear ratios G5 and G8 before and after the shift shown in FIG.
It goes without saying that step 5 may be executed.

[0021]

As described above, according to the first aspect of the present invention, since the engine output characteristic is changed so that the engine output at the time of shifting of the automatic transmission changes in the direction to reduce the shift shock, the shift at the time of shifting is performed. The engine output characteristic does not switch so as to increase the shift shock, and the shift shock of the automatic transmission can be reliably reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a shift shock reducing device according to the present invention.

FIG. 2 is a schematic diagram of a power train and its control system showing an embodiment of the present invention.

FIG. 3 is a flowchart showing a control program executed by the engine controller of the same example.

FIG. 4 is a map diagram showing a combination control pattern of a suitable shift stage and a suitable cam in the same example.

FIG. 5 is an operation time chart during upshift gear shifting in the same example.

FIG. 6 is an operation time chart during downshift gear shifting in the same example.

FIG. 7 is an operational characteristic diagram of three types of intake / exhaust valve cams.

FIG. 8 is an output performance diagram of the engine depending on the proper use of the cam.

[Explanation of symbols] 1 engine 2 automatic transmission 3 air cleaner 4 throttle valve 5 exhaust pipe 6 accelerator pedal 7 throttle actuator 8 cam switching control valve 9 cam switching mechanism 10 transmission output shaft 11 control valve 12 engine controller 13 transmission controller 14 Accelerator stroke sensor

Claims (1)

[Claims] Claim: What is claimed is: 1. A power train in which a variable output characteristic engine that switches and uses a plurality of output characteristics with respect to a throttle opening degree and an automatic transmission that switches and uses a plurality of gears are connected in tandem. And a gear shift detecting means for detecting a gear change, and an output characteristic changing means for changing an engine output characteristic so that the output of the engine changes in a direction to reduce a gear shift shock when the gear shift is detected by the gear shift detecting means. A shift shock reducing device for an automatic transmission in a power train, which is characterized by: