JP3237395B2 - Shift hunting prevention device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing shift hunting of an automatic transmission in a vehicle equipped with a power train including an engine whose output is controlled by an electronically controlled throttle and a hydraulically controlled automatic transmission. Things.

[0002]

2. Description of the Related Art An electronically controlled throttle detects an amount of depression of an accelerator pedal operated by a driver with a potentiometer or the like and inputs the detected amount to a throttle controller. The opening is controlled so as to correspond to the amount of depression, and is already used in some vehicles.

On the other hand, a hydraulically controlled automatic transmission is mechanically connected to the engine throttle by a wire or the like, and is rotated by a transmission output shaft and a throttle valve for generating a throttle pressure corresponding to the throttle opening. A governor valve that generates a governor pressure corresponding to the vehicle speed, and a shift valve that receives the throttle pressure and the governor pressure in opposition and has a stroke position corresponding to a combination of the two, and is defined by a combination of the throttle opening and the vehicle speed. The shift is performed by the stroke of the shift valve on the set shift line.

[0004]

By the way, in a vehicle equipped with a power train including an engine whose output is controlled by the electronically controlled throttle and the hydraulically controlled automatic transmission, an automatic transmission is provided. However, shift hunting easily occurs as described below. That is, FIG. 5 shows the 3 → 4 upshift shift line and 4
→ A shift diagram showing only the 3 downshift shift line, with the 3rd speed 6% load load (R / L) line a, the 3rd speed 7% load load (R / L) line b, and the 4th speed 5% load load. (R /
L) line c, 4-speed 6% load road (R / L) line d are also shown.

Here, a third speed 6% road load (R / L) line a represents a throttle opening for maintaining a corresponding vehicle speed while traveling on a 6% gradient road at a third speed, and other speeds. 3rd gear 7
% Load load (R / L) line b, 4th gear 5% load load (R / L) line c, 4th gear 6% load load (R / L) line d
Mean the same content. Regarding the road load line, December 20, 1979, Kokaido Co., Ltd. published, 3 volumes of automotive engineering, "Automobile Performance and Testing"
On page 31 to page 36, "2.1 Power Performance".

[0006] In FIG. 5, for example, a 6% gradient road consider the case of traveling at the vehicle speed V _1, above the 4-speed 6% load load (R / L) line d is 4 → 3 downshift characteristic curve At 4th speed, it is impossible to run due to insufficient torque.
Accordingly, the driver depresses the accelerator pedal to compensate for the decrease in vehicle speed, and in response, the throttle opening increases as indicated by arrow e, but as a result, the downshift is performed to the third speed. By the way, at the third speed, the torque becomes excessive because the third-speed 6% load road (R / L) line a is below the 3 → 4 upshift line. Therefore, the driver returns the accelerator pedal to avoid the increase in the vehicle speed, and in response, the throttle opening decreases as indicated by arrow f.
As a result, the upshift is performed to the fourth speed.

At 4th speed, the vehicle cannot travel due to insufficient torque as described above, and the driver depresses the accelerator pedal again to compensate for the decrease in vehicle speed. In response, the driver opens the throttle opening as indicated by arrow e. As a result, the gear is downshifted to the third speed. However, in the third speed, as described above, as a result of excessive torque, the driver returns the accelerator pedal again in order to avoid an increase in the vehicle speed, and in response to this, the throttle opening decreases as indicated by arrow f. As a result, the upshift is performed to the fourth speed. With the above repetition, the automatic transmission is inevitably subject to shift hunting in which the shift is repeated between the third speed and the fourth speed.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problem relating to shift hunting of the hydraulically controlled automatic transmission by operating an electronically controlled throttle.

[0009]

SUMMARY OF THE INVENTION To this end, a shift hunting prevention device for an automatic transmission according to the first invention is shown in FIG.
As shown in the concept, in a vehicle equipped with a power train including an engine whose output is controlled by an electronically controlled throttle and a hydraulically controlled automatic transmission, a vehicle speed for maintaining a predetermined vehicle speed for at least two shift speeds Vehicle speed maintaining throttle opening calculating means for calculating a maintaining throttle opening, an upshift generating throttle opening in which a shift from a low speed to a high speed occurs between the shift speeds, and a shift from a high speed to a low speed A shift generating throttle opening calculating means for calculating a downshift generating throttle opening at which the shift is generated, a vehicle speed maintaining throttle opening related to the low speed stage is smaller than the upshift generating throttle opening, and When the throttle opening for maintaining the vehicle speed concerned is larger than the throttle opening at which the downshift occurs, the oil Shift hunting determining means for determining that the controlled automatic transmission is in an operating state in which shift hunting occurs; and, in response to a signal from the control means, in a driving state in which shift hunting occurs, a throttle opening corresponding to an accelerator pedal depression amount. A shift hunting preventing throttle opening calculating means for calculating a throttle opening at which the shift hunting does not occur by reducing the difference between the vehicle speed maintaining throttle opening related to the low speed stage and the upshift generating throttle opening. And a throttle opening correction means for correcting the electronically controlled throttle to a throttle opening calculated by the means.

A shift hunting prevention device for an automatic transmission according to a second aspect of the present invention further includes a road surface gradient calculating means for calculating a gradient of a road surface on which the vehicle is traveling, in addition to the first aspect of the invention. The throttle opening calculating means is configured to calculate the vehicle speed maintaining throttle opening in consideration of the road surface gradient calculated by the road surface gradient calculating means.

According to a third aspect of the present invention, in the second aspect of the invention, the road surface gradient calculating means is configured to determine the road surface gradient in relation to a vehicle uphill torque, a vehicle weight, and a wheel turning radius. Things.

According to a fourth aspect of the present invention, in the third aspect, the road surface gradient calculating means obtains the uphill torque by subtracting the running resistance and the acceleration torque of the vehicle from the engine output torque when obtaining the uphill torque of the vehicle. It is characterized by having such a configuration.

[0013]

In the first aspect of the invention, the output of the engine is controlled by an electronically controlled throttle, and the vehicle is driven by power from a power train including the engine and a hydraulically controlled automatic transmission.

Here, the vehicle speed maintaining throttle opening calculating means calculates the vehicle speed maintaining throttle opening for maintaining a predetermined vehicle speed for at least two shift speeds, and the shift generating throttle opening calculating means comprises: An upshift generating throttle opening at which a shift from a low gear to a high gear occurs between the gears and a downshift generating throttle opening at which a shift from the high gear to the low gear occurs are calculated.

On the basis of the calculation results of these calculation means, the shift hunting determination means determines that the vehicle speed maintaining throttle opening related to the low speed stage is smaller than the upshift occurrence throttle opening and the vehicle speed related to the high speed stage is controlled. When the maintenance throttle opening is larger than the downshift occurrence throttle opening, it is determined that the hydraulically controlled automatic transmission is in an operating state in which shift hunting occurs.

The shift hunting preventing throttle opening calculating means responds to the signal from the shift hunting judging means to calculate the above-mentioned throttle opening from the throttle opening corresponding to the depression amount of the accelerator pedal when the operating state causes shift hunting. The difference between the throttle opening for maintaining the vehicle speed related to the low speed stage and the above-described upshift-occurring throttle opening is reduced to calculate a throttle opening at which the shift hunting does not occur. Is corrected to the throttle opening calculated as described above.

Therefore, shift hunting of the automatic transmission, which tends to occur in a vehicle equipped with a power train including an engine with an electronically controlled throttle and a hydraulically controlled automatic transmission, can be reliably prevented, and the operability of the vehicle is improved. Can be improved.

As described above, the operating state that causes shift hunting is determined by comparing the throttle opening for maintaining the vehicle speed related to the low speed stage and the high speed stage with the throttle opening for generating the upshift and the downshift. Since the determination is made, the shift hunting can be reliably determined, and the above operation and effect can be made more remarkable. Further, the shift hunting preventing throttle opening calculating means subtracts the difference between the throttle opening for maintaining the vehicle speed related to the low speed stage and the throttle opening for generating the upshift from the throttle opening corresponding to the accelerator pedal depression amount. Since the throttle opening at which the shift hunting does not occur is obtained, the throttle opening at which the shift hunting does not occur can be easily obtained by directly using the data obtained at the time of the shift hunting determination. Can be.

In the second invention, the road surface gradient calculating means provided in addition to the first invention calculates the gradient of the vehicle running road surface, and the vehicle speed maintaining throttle opening calculating means considers the calculated road surface gradient. Then, the throttle opening for maintaining the vehicle speed is calculated. In this case, the throttle opening for maintaining the vehicle speed becomes accurate in consideration of the road surface gradient, the shift hunting can be determined with higher accuracy regardless of the road surface gradient, and the throttle opening correction is performed. It can be prevented from being performed wastefully.

In the third invention, the road surface gradient calculating means determines the road surface gradient in the second invention in relation to a vehicle uphill torque, a vehicle weight, and a wheel turning radius. In this case, the road surface gradient θ can be accurately obtained, and the shift hunting can be determined with higher accuracy.

According to a fourth aspect of the present invention, when the road surface gradient calculating means calculates the uphill torque of the vehicle according to the third aspect, the road resistance and the acceleration torque are subtracted from the engine output torque to obtain the uphill torque. In this case, the climbing torque can be accurately calculated, and thus the road surface gradient θ can be accurately determined.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a control system diagram of a vehicle power train illustrating a shift hunting prevention device for an automatic transmission according to the present invention. In the figure, reference numeral 1 denotes an engine whose output is controlled by an electronically controlled throttle, and 2 denotes a hydraulically controlled automatic transmission, respectively. A tandem combination of the engine 1 and the automatic transmission 2 constitutes a power train for a vehicle.

The engine 1 is controlled by a well-known engine controller (not shown) to control the fuel injection amount, ignition timing, exhaust gas recirculation amount, and the like, and the throttle controller 3 controls the throttle opening through a throttle actuator 4. And the above-described engine output control. In controlling the engine output, the throttle controller 3 basically responds to a signal from a potentiometer 6 for detecting the amount of depression of an accelerator pedal 5 operated by the driver, and adjusts the throttle opening degree via a throttle actuator 4. It is assumed that the opening is set to correspond to the depression amount of the pedal 5.

The automatic transmission 2 is a four-speed forward transmission, and includes a control valve 7 having a throttle valve 8, a governor valve 9, and shift valves 10 and 11. Here, the throttle valve 8 generates a throttle pressure corresponding to the throttle opening in mechanical linkage with the throttle of the engine, and the governor valve 9 is rotated by a transmission output shaft to generate a governor pressure corresponding to the vehicle speed.
The shift positions of the shift valves 10 and 11 are determined by receiving the throttle pressure and the governor pressure, respectively, and the first to fourth speeds are selected based on a combination of the stroke positions of the shift valves 10 and 11. Shall be. It should be noted that the third shift speed and the fourth shift speed achieved by one of the shift valves 11 switching the stroke position.
The speed change is performed on the 3 → 4 upshift shift line and the 4 → 3 downshift shift line similar to those in FIG.

The throttle controller 3 detects the throttle opening TH in addition to the normal throttle opening control described above in order to correct the throttle opening to be performed in order to prevent shift hunting of the automatic transmission 2 according to the present invention. The signal from the throttle opening sensor 12, the signal from the transmission output rotation sensor 13 for detecting the transmission output rotation speed No, and the signal from the engine rotation sensor 14 for detecting the engine rotation speed Ne are separately input. The control program shown in FIG. 3 is executed based on the input information.
The control program shown in FIG. 3 is for preventing shift hunting in 3 → 4, 4 → 3 shift.

In FIG. 3, first, at step 21 corresponding to the road surface gradient calculating means, the road surface gradient θ is changed to θ = sin ^−1.
It is calculated by [vehicle uphill torque / (vehicle weight × wheel turning radius)]. Here, when obtaining the climbing torque of the vehicle, the throttle opening TH and the engine speed Ne are calculated.
Of the vehicle running resistance and the change of the vehicle speed which can be obtained from the 0% load road line (from the map of the vehicle speed VSP obtained from the transmission output rotation speed No) from the engine output torque which can be obtained from the map (or from the characteristics of the torque converter). The climbing torque is obtained by subtracting the acceleration torque that can be obtained from the ratio x the vehicle weight x the wheel turning radius.

The next step 22 corresponds to a shift generating throttle opening calculating means.
Using a virtual shift line map that stores the relationship between the vehicle speed and the throttle opening TH at which a shift of the transmission is likely to occur due to the strokes 0 and 11 described above, a downshift of 4 → 3 from the detected current vehicle speed. Shift occurrence throttle opening T
H (4 → 3) and the upshift occurrence throttle opening TH (3 → 4) for shifting 3 → 4 are calculated.

The next step 23 corresponds to a vehicle speed maintenance throttle opening calculating means. Here, the road surface gradient θ in step 21 and the current vehicle speed VSP are calculated using a road road map which is a running characteristic of the vehicle. The throttle opening TH (3) for maintaining the vehicle speed at the low speed where the vehicle can travel on the road gradient θ at the current speed at the third speed, and the vehicle speed at the high speed where the road gradient θ can travel at the current speed at the fourth speed The maintenance throttle opening TH (4) is calculated.

The next step 24 corresponds to a shift hunting determining means. Here, the road surface gradient θ is set to the current vehicle speed at the fourth speed from the downshift occurrence throttle opening TH (4 → 3) at which the 4 → 3 shift occurs. The throttle opening TH (4) for maintaining the vehicle speed of the high speed stage capable of traveling at high speed is large and the throttle opening TH (3
From (4), it is determined whether or not the throttle opening TH (3) for maintaining the vehicle speed at the low speed where the vehicle can travel on the road gradient θ at the current vehicle speed at the third speed is small. Here it is added that every case where the gradient θ is traveling at a vehicle speed that indicates the upper 6% of the road at V ₁ of the FIG. 5, the downshift occurs throttle opening TH (4 →
3) is the throttle opening value at the intersection of the arrow e with the 4 → 3 downshift line in FIG. 3 and the throttle opening TH (4) for maintaining the vehicle speed at the high speed is V _{1 in} FIG. , The throttle opening value on the 4th speed 6% load road (R / L) line d, and the upshift occurrence throttle opening TH (3 → 4) is the 3 → 4 upshift shift line in FIG. and a throttle opening value at the intersection of the arrows f, the vehicle speed maintained throttle opening TH (3) of the low-speed stage, third speed 6% loading load when the vehicle speed is V ₁ of the drawing (R / L )
This is the throttle opening value on the line a. As is apparent from the above description, if step 24 is determined to be YES, shift hunting is caused. If it is determined to be NO, shift launching is not caused.

If it is determined in step 24 that the shift hunting is to be performed, in step 25 corresponding to the shift hunting preventing throttle opening calculating means, the program proceeds to step 2 based on the throttle opening corresponding to the accelerator pedal depression amount.
Upshift occurrence throttle opening TH (3 → 2)
The difference value between 4) and the throttle opening TH (3) for maintaining the vehicle speed at the low speed stage in step 23 is subtracted to obtain the throttle opening of the electronically controlled throttle of the engine.

If it is determined in step 24 that the shift hunting is not performed, in step 26, the accelerator pedal depression amount is made to correspond to the throttle opening of the electronically controlled throttle of the engine by normal control.

By this correction of the throttle opening, for example, the throttle opening is made smaller than the opening corresponding to the amount of depression of the accelerator pedal.
As shown in FIG. 4, a load load (R / L) line a and a 3rd-speed 7% load load (R / L) line b are shown in FIG. 4, respectively. It becomes a load (R / L) line. Thus becomes the third speed 6% load load (R / L) line b is present above the 3 → 4 upshift line, running keeping the vehicle speed V ₁ by the operation of the X-point of the line Can be realized without causing shift hunting. In this embodiment, 3
Although the description has been given of the shift hunting prevention of the → 4, 4 → 3 shift, it is obvious that the shift hunting may be used in other shift speeds. In this embodiment, the throttle opening is reduced in order to prevent the shift hunting. Conversely, the gear ratio may be increased to maintain the higher gear by increasing the engine torque.

[0033]

As described above, the shift hunting preventing device for an automatic transmission according to the first aspect of the present invention generates the shift hunting when the hydraulically controlled automatic transmission is in an operating state in which the shift hunting occurs. Since the throttle opening that disappears is calculated and the electronically controlled throttle is corrected to the throttle opening calculated as described above, a power train including an engine with an electronically controlled throttle and a hydraulically controlled automatic transmission is provided. , The shift hunting of the automatic transmission, which is likely to occur in the vehicle equipped with the vehicle, can be reliably prevented, and the drivability of the vehicle can be improved. By the way, in the first aspect of the invention, when determining that the vehicle is in an operating state in which shift hunting occurs, a throttle opening for maintaining a vehicle speed for maintaining a predetermined vehicle speed for at least two shift speeds, and a low speed between the shift speeds. Compare the upshift occurrence throttle opening at which the shift from the first gear to the high gear occurs and the downshift occurrence throttle opening at which the shift from the high gear to the low gear occurs,
Shift hunting is performed when the throttle opening for maintaining the vehicle speed at the low speed stage is smaller than the throttle opening at which the upshift occurs, and the throttle opening for maintaining the vehicle speed at the high speed stage is greater than the throttle opening at which the downshift occurs. Since it is determined that the operating state occurs, the shift hunting can be reliably determined, and the above operation and effect can be further remarkable.

In the first aspect of the present invention, when determining the throttle opening at which the shift hunting does not occur,
Since the difference between the throttle opening for maintaining the low-speed gear and the above-described throttle opening for upshifting is obtained from the throttle opening corresponding to the amount of depression of the accelerator pedal, the throttle opening at which shift hunting does not occur is determined. When obtaining the shift hunting, the throttle opening at which the shift hunting does not occur can be easily obtained by diverting the data obtained in the determination of the shift hunting as it is.

According to a second aspect of the present invention, a shift hunting prevention device for an automatic transmission calculates a gradient of a road surface on which a vehicle is running, and calculates the above-mentioned throttle opening for maintaining vehicle speed in consideration of the road surface gradient. Because of the calculation, the throttle opening for maintaining the vehicle speed is accurate considering the road surface gradient,
The shift hunting can be determined with higher accuracy irrespective of the road gradient, and the throttle opening correction can be prevented from being wasted.

According to a third aspect of the present invention, there is provided a shift hunting prevention device for an automatic transmission, wherein a road surface gradient θ is provided.
Is determined in relation to the climbing torque of the vehicle, the vehicle weight, and the wheel turning radius, the road surface gradient θ can be accurately obtained, and the shift hunting can be determined with higher accuracy. .

According to a fourth aspect of the present invention, a shift hunting prevention device for an automatic transmission according to a fourth aspect of the present invention calculates a climbing torque by subtracting a running resistance and an acceleration torque of the vehicle from an engine output torque. Since the configuration is such that the torque is obtained, the climbing torque can be accurately calculated, and thus the road surface gradient θ can be accurately obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a shift hunting prevention device for an automatic transmission according to the present invention.

FIG. 2 is a control system diagram of a vehicle power train showing one embodiment of a shift hunting prevention device according to the present invention.

FIG. 3 is a flowchart showing a throttle opening correction control program for shift hunting prevention executed by a throttle controller in the example.

FIG. 4 is a shift diagram and a road load diagram showing a shift hunting prevention effect by the throttle opening correction operation.

FIG. 5 is a shift diagram and a road load diagram of a conventional vehicle equipped with a power train including an engine with an electronically controlled throttle and a hydraulically controlled automatic transmission.

[Explanation of symbols]

 Reference Signs List 1 engine with electronically controlled throttle 2 hydraulically controlled automatic transmission 3 throttle controller 4 throttle actuator 5 accelerator pedal 6 potentiometer 7 control valve 8 throttle valve 9 governor valve 10 shift valve 11 shift valve 12 throttle opening sensor 13 transmission output rotation sensor 14 Engine rotation sensor

────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification symbol FI // F16H 59:68 F16H 59:68 (58) Investigated field (Int.Cl. ⁷ , DB name) F02D 29/00 B60K 41 / 00,41 / 04 F16H 59/00-61/02

Claims (4)

(57) [Claims] 1. A vehicle equipped with a power train including an engine whose output is controlled by an electronically controlled throttle and a hydraulically controlled automatic transmission, for maintaining a vehicle speed for maintaining a predetermined vehicle speed for at least two shift speeds. A vehicle speed maintenance throttle opening calculating means for calculating a throttle opening, an upshift occurrence throttle opening in which a shift from a low speed to a high speed occurs between the shift speeds, and a shift from a high speed to a low speed. A shift generating throttle opening calculating means for calculating a downshift generating throttle opening; and a vehicle speed maintaining throttle opening for the low speed stage is smaller than the upshift generating throttle opening, and a vehicle speed for the high speed stage. When the maintenance throttle opening is larger than the downshift occurrence throttle opening, the hydraulic control type A shift hunting determining means for determining that the dynamic transmission is in an operating state in which shift hunting occurs; and, in response to a signal from the means, in an operating state in which shift hunting is performed, the throttle opening corresponding to the amount of depression of the accelerator pedal, A shift hunting preventing throttle opening calculating means for calculating a throttle opening which reduces the difference between the vehicle speed maintaining throttle opening related to the low speed stage and the upshift generating throttle opening to prevent the shift hunting; Electronically controlled throttle
A shift hunting prevention device for an automatic transmission, comprising: throttle opening correction means for correcting the throttle opening calculated by the means. 2. The vehicle according to claim 1, further comprising a road surface gradient calculating means for calculating a gradient of a road surface on which the vehicle is traveling, wherein said vehicle speed maintaining throttle opening calculating means includes a road surface calculated by said road surface gradient calculating device. A shift hunting prevention device for an automatic transmission, wherein the throttle opening for maintaining the vehicle speed is calculated in consideration of a gradient. 3. The shift hunting of an automatic transmission according to claim 2, wherein said road surface gradient calculating means is configured to calculate the road surface gradient in relation to a vehicle uphill torque, a vehicle weight, and a wheel turning radius. Prevention device. 4. The vehicle according to claim 3, wherein the road surface gradient calculating means is configured to obtain the uphill torque by subtracting the running resistance and the acceleration torque of the vehicle from the engine output torque when obtaining the uphill torque of the vehicle. Shift hunting prevention device for an automatic transmission.