JP2913960B2 - Transmission control device for automatic transmission in power train - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission in a power train in tandem connection with an engine having variable output characteristics and an automatic transmission.

[0002]

2. Description of the Related Art As an engine with variable output characteristics, for example, as disclosed in Japanese Patent Application Laid-Open No. 3-111610, an output characteristic with respect to a throttle opening degree is determined by selectively using a plurality of engine intake / exhaust valve control cams. There is known a so-called variable valve type engine capable of switching between the two. This engine is provided with three types of cams for each intake and exhaust valve. These cams, that is, fuel efficiency cams (hereinafter referred to as P-cams) with an emphasis on fuel efficiency when the engine is partially loaded as shown in FIG. ), And a low-speed cam (hereinafter, referred to as L cam) useful during low rotation and a high-speed cam (hereinafter, referred to as H cam) useful during high rotation, based on the required engine load and engine speed. They are used properly to match the state. As shown in FIG. 4, which shows the output characteristics when the throttle is fully opened, the engine can switch the output characteristics when using the P cam, when using the L cam, and when using the H cam.

[0003] On the other hand, as shown in, for example, an RE4R01A type automatic transmission (see the maintenance manual) developed and used by the present applicant, an automatic transmission is shown in Fig. 5 which is preset as a combination of an engine throttle opening and a vehicle speed. It is customary to determine a suitable gear position based on the exemplified shift pattern and selectively hydraulically actuate (engage) various friction elements (clutch, brake) so as to select the suitable gear position.

[0004]

However, in such a power train in which the engine and the automatic transmission are connected in tandem, the automatic transmission performs shift control based on one type of shift pattern. The gear stage is determined separately from the combination of the throttle opening and the engine speed. Therefore, this gear shift control does not take into account what cam is being selected, which causes the following problems. Is generated.

That is, the engine output differs depending on the selected cam (engine output characteristic) even under the same throttle opening as shown in FIG. In the conventional automatic transmission that performs shift control from the throttle opening and the vehicle speed based on the cam, the selected shift speed is not determined in consideration of the cam, and the shift speed is not necessarily a suitable shift speed that matches a different engine output according to the cam. .

According to the present invention, the automatic transmission is not limited to one type of shift pattern, but is switched in accordance with a change in the engine output characteristic, thereby taking into account the currently selected engine output characteristic in the shift control. The aim is to eliminate the problem. However, in this case, since the change of the shift pattern often involves a shift, and this shift is performed simultaneously with the switch of the engine output characteristic, the shock due to the switch of the engine output characteristic and the shift shock are simultaneously performed. It is feared that the shock will increase. The problem of the shock is particularly remarkable when the shift accompanying the switching of the shift pattern is a downshift to a low gear, and conversely, when the shift is an upshift to a high gear, an unpleasant increase in the engine speed is caused. In order to prevent this, it is preferable that the shift be performed without delay. SUMMARY OF THE INVENTION It is an object of the present invention to propose a shift control device for an automatic transmission, which solves the above-mentioned problem of the shock while taking these circumstances into consideration.

[0007]

For this purpose, claim 1 is provided.
According to a first aspect of the present invention, there is provided a power train in tandem coupling between an output characteristic variable engine that switches and uses a plurality of output characteristics with respect to a throttle opening and an automatic transmission that is controlled to shift based on a preset shift pattern. A shift pattern switching means for changing the preset shift pattern in accordance with the selected engine output characteristic, wherein the first shift control immediately after the switching of the engine output characteristic is performed based on the shift pattern before the change. It is characterized in that pattern change delay means is provided. According to a second aspect of the present invention, there is provided a tandem coupling between an output characteristic variable engine that switches between a plurality of output characteristics with respect to a throttle opening and an automatic transmission that is controlled to be shifted based on a preset shift pattern. The power train includes a shift pattern switching unit that changes the preset shift pattern according to the selected engine output characteristic, and performs the first shift control immediately after switching of the engine output characteristic to the changed shift pattern. If the shift based on is a downshift to a lower gear, the shift pattern is changed based on the shift pattern before the change, and if the shift is an upshift to a higher gear, the shift pattern is changed based on the changed shift pattern. A mode determining means is provided.

[0008]

According to the first aspect of the invention, the output characteristics of the engine are switched, and the power determined by the output characteristics is generated and input to the automatic transmission. The automatic transmission shifts and outputs the engine power at a gear ratio corresponding to the selected shift speed. When the automatic transmission determines a gear, the gear shift pattern switching means determines the gear based on the gear shift pattern selected according to the current engine output characteristics.
For this reason, the engine output characteristics are taken into account in the shift control of the automatic transmission, and even if the engine output differs for each engine output characteristic, the gear stage can always be a suitable gear stage that matches the engine output. On the other hand, the shift pattern change delay means causes the first shift control immediately after the switching of the engine output characteristic to be performed based on the shift pattern before the change. As a result, it is possible to prevent a shift from occurring immediately after the switching of the engine output characteristics, and it is possible to eliminate the problem that the shift shock and the shock accompanying the switching of the engine output characteristics occur simultaneously and adversely affect the drivability. it can. In the second invention, the shift pattern change mode determining means changes the shift pattern as follows. That is, the first shift control immediately after the switching of the engine output characteristic is changed to the high speed stage based on the shift pattern before the change, if the shift based on the changed shift pattern is a downshift to the low speed stage. In the case of the upshift, the shift pattern is changed so as to be performed based on the changed shift pattern. As a result, a downshift can be prevented from occurring immediately after the switching of the engine output characteristics, and the downshift shift shock and the shock accompanying the switching of the engine output characteristics occur simultaneously, which adversely affects the drivability. Can be eliminated. However, in the case of an upshift in which the adverse effect on the drivability does not become a major problem, the shift can be immediately performed, thereby preventing an unpleasant increase in the engine speed and thereby improving the drivability. Deterioration can be prevented.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a power train control system showing one embodiment of the transmission control apparatus of the present invention. Reference numeral 1 denotes an engine with variable output characteristics, and reference numeral 2 denotes an automatic transmission. It is assumed that the transmission is appropriately shifted.

The engine 1 burns the injected fuel by the air sucked from the air cleaner 3 via the throttle valve 4, inputs the resulting power to the automatic transmission 2, and outputs the combustion exhaust gas to the outside through an exhaust pipe 5. To be released. The engine 1 has a variable valve as described in Japanese Patent Laid-Open No. 3-111610 described above with reference to FIGS. The three types of cams are switched by the cam switching mechanism 6.

The automatic transmission 2 changes the rotational power from the engine 1 at a gear ratio corresponding to the selected gear and transmits it to an output shaft.
It is used for driving the wheels of the vehicle and is described in "RE4R01A-type automatic transmission maintenance manual" issued by Nissan Motor Co., Ltd., and is controlled electronically via the control valve 7.

The cam switching control via the cam switching mechanism 6 of the engine 1 is performed by the cam switching control means 8, and the shift control via the control valve 7 of the automatic transmission is performed by the shift control means 9.

The cam switching control means 8 obtains a preferred cam among the three types of cams based on a map set in advance from the required engine load and the engine speed, and supplies a corresponding cam command to the cam switching mechanism 6. , Causes the engine 1 to select a suitable cam.

The shift control means 9 is provided for each of the three types of cams as shown in FIG.
Has three built-in speed change patterns. In the present embodiment, in view of the above object of the present invention, a shift pattern switching means 10 is provided, and this means detects a cam currently selected by the engine from a signal from the cam switching control means 8 and responds to the selected cam. It is assumed that the shift control means 9 selects the shift pattern thus set. The shift control means 9 determines the shift speed from the throttle opening and the vehicle speed based on the shift pattern thus determined, and supplies a corresponding command to the control valve 7 to change the shift speed to the automatic transmission 2. To select.

By the way, as is clear from the above-mentioned processing,
Since the shift control is performed based on the shift pattern switched according to the selected cam, the selected cam is taken into account in the shift control. It can be a good one that matches the output.

When the means 8, 9, and 10 in FIG. 1 are constituted by one microcomputer, the control program is as shown in FIG. That is, first, step 11
, The cam switching control is executed, and in the next step 12, it is checked whether or not the cam has been switched as a result of the control. If there is a cam switch, step 1
The gear shift pattern corresponding to the cam after the switch is switched in step 3, and in the next step 14, the gear position is determined from the throttle opening and the vehicle speed based on the gear shift pattern, and the gear shift control for switching the automatic transmission 2 to this gear position is performed. Execute.

When it is determined in step 12 that there is no cam switching, step 13 is skipped and the shift pattern is not switched, and the shift control based on the same shift pattern is performed in step 14.

Also in this case, the gear shift pattern is switched according to the selected cam, so that even if the engine output differs according to the cam, the gear stage can always be set to a suitable one that matches the engine output. .

In this embodiment, the switching of the cam and the switching of the shift pattern are executed by the following timing control. The first shift control immediately after the cam switching is executed based on the previous shift pattern, and the shift control is performed based on the shift pattern updated from the next time. The reason is that in the shift control based on the shift pattern changed in response to the switching of the cam, there is a high possibility that the shift stage is switched, and when the shift control is performed from the first time based on the updated shift pattern, The gears are changed at the same time as the gears are changed, and the shocks accompanying these changes occur simultaneously.
This is because drivability is adversely affected. According to the shift pattern switching delay control described above, it is possible to shift the shift generation timing associated with the shift pattern switching from the cam switching timing, so that a shock due to the shift and a shock due to the cam switching occur simultaneously. As a result, the above problem that drivability deteriorates can be solved. In another method, a suitable shift speed is determined based on the updated shift pattern for the time being. As a result, if a downshift to a lower speed is required, switching of the shift pattern is similarly delayed for the same purpose as above, and if an upshift is required, The shift is immediately executed to prevent an unpleasant increase in the engine speed due to the delay of the upshift, and prioritize drivability. In other words, when the first shift control immediately after the cam changeover is performed, if the shift based on the changed shift pattern is a downshift to the lower gear, the upshift to the higher gear is performed based on the shift pattern before the change. If it is a shift, the shift pattern is changed so as to be performed based on the changed shift pattern. For this reason, it is possible to avoid the occurrence of a downshift immediately after the cam is switched, and it is possible to eliminate the problem that the downshift gear shift shock and the shock accompanying the cam switching occur simultaneously, which adversely affects the drivability. However, in the case of an upshift in which the adverse effect on the drivability does not become a major problem, the shift is immediately performed, thereby preventing an unpleasant increase in the engine speed and deteriorating the drivability. Priority can be given to the shift control for preventing the shift. Of course,
If the shift determination based on the changed shift pattern is such that neither a downshift nor an upshift is necessary, there is no shock associated with the shift, so there is no need to delay switching of the shift pattern. The same processing as that for shifting can be performed.

[0020]

As described above, the shift control device according to the present invention has a structure in which the shift pattern is changed in accordance with the switching of the engine output characteristic as described in the first and second aspects. The shift control of the automatic transmission according to the above takes into account the engine output characteristics being selected.Although the engine output varies depending on the output characteristics, it is necessary to always make the selected shift speed suitable for the engine output. Can be. In the first invention, in particular, since the first shift control immediately after the switching of the engine output characteristic is performed based on the shift pattern before the change, it is possible to avoid a shift from occurring immediately after the switching of the engine output characteristic, It is possible to eliminate the problem that the shift shock and the shock accompanying the switching of the engine output characteristics occur simultaneously, which adversely affects the drivability. Further, in the second invention, the first shift control immediately after the switching of the engine output characteristic is performed based on the shift pattern before the change when the shift based on the changed shift pattern is a downshift to a lower gear. Conversely, in the case of an upshift to a higher gear, the shift pattern is changed so as to be performed based on the changed shift pattern, so that a downshift can be avoided immediately after switching of the engine output characteristics. This eliminates the problem that the downshift gear shift shock and the shock accompanying the switching of the engine output characteristics occur simultaneously to adversely affect the drivability, and is an upshift in which the adverse effect on the drivability does not become a major problem. In this case, the shift can be performed immediately, thereby preventing an unpleasant increase in the engine speed. Driveability deterioration due can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram of a power train control system showing one embodiment of a transmission control device of the present invention.

FIG. 2 is a flowchart showing a control program when the same example is configured by a microcomputer.

FIG. 3 is an operational characteristic diagram of three types of intake and exhaust valve cams.

FIG. 4 is an output performance diagram of the engine when the cam is used properly.

FIG. 5 is a conventional shift pattern diagram of an automatic transmission.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 engine 2 automatic transmission 3 air cleaner 4 throttle valve 5 exhaust pipe 6 cam switching mechanism 7 control valve 8 cam switching control means 9 shift control means 10 shift pattern switching means

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48 B60K 41 / 04

Claims (2)

(57) [Claims] 1. A power train that is in tandem with an output characteristic variable engine that switches and uses a plurality of output characteristics with respect to a throttle opening degree and an automatic transmission that is controlled to shift based on a preset shift pattern, is selected. A shift pattern changing means for changing the preset shift pattern in accordance with the engine output characteristic of the engine, wherein a first shift control immediately after the switching of the engine output characteristic is performed based on the shift pattern before the change. A shift control device for an automatic transmission in a power train, characterized by comprising means. 2. A power train that is in tandem with an output characteristic variable engine that switches and uses a plurality of output characteristics with respect to a throttle opening degree and an automatic transmission that is shifted based on a preset shift pattern is selected. A shift pattern switching means for changing the previously set shift pattern in accordance with the engine output characteristic of the first shift control. The first shift control immediately after the switching of the engine output characteristic shifts the shift based on the changed shift pattern to a lower gear. If the downshift is an upshift to a higher gear based on the shift pattern before the change,
A shift control device for an automatic transmission in a power train, further comprising shift pattern change mode determining means for performing a shift pattern change based on the changed shift pattern.