JP3481906B2 - Automatic transmission control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a transmission of an automobile. The present invention relates to an improvement of a device for calculating an appropriate transmission gear to be selected by a program calculation circuit. INDUSTRIAL APPLICABILITY The present invention is used not only for an automatic vehicle without a clutch pedal, but also only when the clutch pedal requires a delicate clutch operation such as when starting, and the gear shift during running is automatically executed without operating the clutch pedal each time. It can be used for semi-automatic vehicles. The present invention is a device developed to be applied to a large-sized tow vehicle equipped with a forward speed change gear of a dozen stages, but can be widely used in other vehicles.

[0002]

2. Description of the Related Art Automatic transmissions having a program calculation circuit have been widely used in large vehicles. The automatic transmission is characterized in that the driver's fatigue can be reduced, the transmission gear can be properly selected, and smooth traveling can be performed.

The automatic transmission takes in vehicle speed information, engine rotation speed information, accelerator operation information and other states and operation information, and should be selected at that time in light of the engine characteristics set as reference data in advance. It is provided with a program control circuit for estimating and calculating an optimum transmission gear. If the program control circuit determines that there is a possibility that the currently selected transmission gear may exceed the range that can be covered by the engine characteristics in response to changes in vehicle speed, the clutch is disengaged even if there is no driving operation. Automatically execute a series of shift operations such as reducing the fuel supply of the engine, changing the shift gear to the optimum one by estimation calculation, engaging the clutch, increasing the fuel supply of the engine, etc. Control. Further, the program control circuit is configured to execute and control a shift operation such as forward, backward, shift up, shift down, and neutral according to operation information of a shift instruction lever provided in a driver's seat.

For example, when the driver intends to overtake a preceding vehicle while the vehicle is traveling at a steady speed and the gear shift instruction lever is operated to shift down to increase the speed, the program control circuit shifts down according to the driving operation. Is configured to run. The same applies to shift-up.

Further, in a transmission having an extremely large number of shift gears (for example, 16 forward gears), when the automatic shift operation is executed, the driver cannot know which shift gear is currently selected. A configuration is known in which the number of the currently selected transmission gear is displayed on the driver's seat as a number. A device for displaying the number of gears that can be changed from the current traveling state by an upward arrow and a downward arrow is also widely used for the numerical display. When the driver inputs an operation instruction while looking at this display, for example, if the shift instruction lever is operated twice to the "UP" side, a two-step shift up is executed, and if the shift instruction lever is operated once to the "DOWN" side.
Downshift of the stage is executed.

While the vehicle is traveling on the road, the driver intends to execute downshifting or upshifting in large steps to move the gear shift instruction lever to "DOWN" or "U" many times.
Even if it is operated to "P", it is designed so that the shift is not executed beyond the displayed number of gears. Especially in the case of downshifting, if the clutch is brought into contact at the final stage of the gear shifting operation, the engine speed may become abnormally high (red zone) corresponding to the vehicle speed at that time. The program control circuit of (1) has safety measures taken so that it will not be executed even if such a downshift is performed.

[0007]

The inventor of the present application repeatedly performed various running tests in order to design a new automatic transmission. Among them, in order to use the engine brake more effectively while the vehicle is traveling on a downhill, when the gear change instruction lever is operated to “DOWN” and the downshift is executed, the gear change operation is executed during execution. When the vehicle is accelerating due to the road gradient and the shift operation is completed and the clutch is in the engagement state, we encountered a phenomenon in which the engine rotation speed became higher than the rotation speed estimated before execution of the shift operation. . The automatic speed change operation is an operation in which the clutch is disengaged, the accelerator is squeezed, the transmission gear is replaced with another gear, the clutch is put in the contact state, and the accelerator is opened. The time required for this is 2 to 4 seconds. is there.
During this time, the vehicle accelerates downhill without engine braking. That is, this is an inconvenient phenomenon that, when the clutch is brought into the engagement state at the final stage of the gear shifting operation, the engine rotation speed becomes temporarily higher than the value estimated at the time when the gear shifting operation was started.

In reality, in the downshift gear shifting operation,
When you try to remove a previously used gear and insert a new gear, the clutch is temporarily put in the neutral state and the engine speed is automatically increased so that the gears are easily engaged. It is designed. Therefore, if the vehicle speed increases after the clutch is disengaged as described above, the engine speed limiting device operates when the engine speed approaches the abnormal range even if the engine speed is increased, Does not increase to a suitable rotation speed for gear engagement. Therefore, the above-mentioned inconvenient phenomenon often appears in a state where the gear instructed to shift down does not enter the neutral state while traveling on the downhill. Such a state is extremely inconvenient for driving. Further, such a state may be understood by the user as a malfunction of the automatic transmission.

In the conventional automatic transmission, no consideration is given to such a phenomenon. That is, the conventional device is designed to execute downshifting assuming that the vehicle speed immediately before the shift operation is maintained even if the vehicle speed changes unplanned due to the road surface gradient during the shift operation. If the downshift gear is engaged while the vehicle speed is increasing, this does not cause the engine to malfunction immediately, but if this is repeated, deterioration of the engine will be accelerated and this is not desirable.

The same inconvenience can occur in the case of upshifting, though the effect is relatively slight. That is, if the driver performs an instruction to shift up while the vehicle is traveling on a gentle uphill, the vehicle decelerates beyond the estimated value during the shift operation execution period for shifting up, It is also possible that the engine speed becomes abnormally low when the clutch is brought into the engaged state after the shift operation is executed. I get the impression that running is not smooth when the engine speed becomes abnormally low. In other words, the riding comfort becomes poor.

The present invention has been made against such a background, and an automatic transmission capable of selecting a transmission gear in consideration of a change in vehicle speed due to a gradient of a traveling road surface which occurs during execution of a gear shifting operation. The purpose is to provide. The present invention, during the shifting operation of the automatic transmission,
An object of the present invention is to prevent the engine speed from becoming an abnormally high speed or an abnormally low speed at the time when the vehicle speed fluctuates and the shift operation is completed. According to the present invention, the speed change operation cannot be executed because the engine speed does not follow the vehicle speed after downshifting or upshifting.
Another object of the present invention is to provide an automatic transmission capable of avoiding a phenomenon such as a gear not entering. An object of the present invention is to provide an automatic transmission capable of extending the life of the engine. SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic transmission that runs smoothly and has a comfortable ride.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a vehicle according to a vehicle gradient according to a vehicle gradient in a period during which a shift operation is performed, that is, in a few seconds until a clutch is disengaged to change a transmission gear and a clutch is engaged. When the speed change gear is selected in consideration of the amount of change in the speed increasing (down slope) or decreasing speed (up slope), if the vehicle speed is changing during the speed change operation after the speed change operation is finished, It is characterized in that the shift to a shift gear in which the engine becomes an abnormally high speed or an abnormally low speed at the end of the shifting operation is prohibited.

That is, the present invention takes in vehicle speed information (1), engine rotation speed information (2), accelerator operation information (4), and gear change instruction lever operation information (6) and automatically selects the optimum shift gear. The program control circuit (10) is provided with a means for performing selective control, and further, when the program control circuit (10) causes an abnormally high engine speed when the selected shift gear is shifted, the program control circuit (10) In an automatic shift control device having means for prohibiting shifting to a selected shift gear, the program control circuit (10) has means for recognizing a gradient of a traveling road surface, and the gradient according to the gradient during execution of a shift operation. Means for estimating and calculating the engine speed after the gear shift operation by adding the vehicle speed variation is provided, and the means for inhibiting the gear shift is the engine calculated by the means for estimating and calculating. Down rotational speed, characterized in that it comprises a means for inhibiting the shifting of the gear to be abnormally fast.

Further, according to the present invention, the program control circuit (10) further includes, as means for inhibiting the shift, a shift to a shift gear at which the engine rotation speed calculated by the estimation calculation means becomes an abnormally low speed. The configuration may include a prohibition unit.

The numerals in the above parentheses are the reference numerals in the drawings of the embodiment apparatus which will be described later. This is given so that the structure of the invention can be easily understood, and is not intended to limit the structure of the invention to an understanding.

With this configuration, when the engine speed becomes abnormally high speed or abnormally low speed after shifting due to a change in vehicle speed that occurs during execution of the shifting operation, such a shifting gear is the target of the shifting target gear. Therefore, it is possible to avoid such a problem that the rotation speed of the engine becomes abnormally high speed (or abnormally low speed), or the gear is not engaged during the automatic shift execution operation.

There are the following two methods for recognizing the gradient of the traveling road surface.

First, a gradient sensor is provided in the vehicle and the output information is used. Alternatively, when the vehicle is already provided with a gradient sensor for use other than the transmission, the output of the gradient sensor is used. Regarding the longitudinal acceleration of the vehicle, the gradient of the traveling road surface can be estimated from the output of the gradient sensor. For example, it can be used by subtracting the influence of the acceleration due to the change in the vehicle speed from the output information obtained from the gradient sensor regarding the longitudinal acceleration of the vehicle. This technique is already known. Further, it is not always necessary to recognize the gradient of the road surface (angle θ or tan θ) itself, and it is possible to recognize and use some physical quantity having a functional relationship with the gradient. For the physical quantity, the exact functional relationship with respect to the road surface gradient does not have to be clear from a mathematical formula. This is referred to as "gradient information" in this specification.

The second method for recognizing the gradient of the traveling road surface is used when the present invention is applied to a vehicle in which a gradient sensor is not provided. This is to estimate the gradient of the traveling road surface by utilizing the changes in the engine load and the vehicle speed before the shift operation is performed, preferably immediately before the shift operation is performed. Even in this case, even if the road surface gradient is not accurate or the quantity is not exactly in the functional relationship, it is "gradient information" as in the above-mentioned purpose and can be used accordingly.

Specifically, the engine load can be obtained as a value proportional to the engine fuel supply amount per hour, that is, the fuel flow rate. The change in vehicle speed is a time differential value (acceleration) of the vehicle speed. Further, information such as the gear ratio of the transmission gear used at that time and the mass of the vehicle is required. The control circuit is always aware of the gear ratio of the transmission gear used.

The vehicle mass relates to the weight of the vehicle (fixed value) and the size of the load (variable value). When there is a towed vehicle, it is necessary to consider the weight of the towed vehicle and the size of the load. However, in principle, the vehicle mass does not fluctuate during driving. The theoretical fluctuation is related to fuel consumption and is small. The approximate value of the vehicle mass can be input by the driver's operation setting at the start of running, and it can also be taken in from the change in the body suspension, and the engine can be used for acceleration on a flat road surface after starting running. It is also possible to automatically set the measurement from the load. For setting and taking in the vehicle mass, a technology already known in the art such as a vehicle attitude control device or a rollover prevention device can be used.

In the case where the output information of the gradient sensor cannot be obtained, a more specific example for obtaining the gradient information will be described. A plurality of control maps prepared in advance according to the engine characteristics are set in the program control circuit. This can be achieved reasonably by keeping it.
That is, the engine load is calculated from the information of the fuel supply amount per hour of the engine and the engine rotation speed information, and the corresponding curve of the engine load (or the torque generated by the engine) and the vehicle acceleration is set with the magnitude of the road surface gradient as a parameter. What you draw is the control map. A large number of the control maps are prepared corresponding to the combination of the transmission gear ratio and the vehicle mass, and it is configured to select which control map to use according to the changing situation.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a block diagram of an apparatus according to the first embodiment of the present invention. The first embodiment device is a device that can detect the gradient information of the traveling road surface by using the gradient sensor. This apparatus includes a program control circuit 10, and the program control circuit 10 includes:
Vehicle speed information 1, engine rotation speed information 2, gradient sensor output information 3, accelerator operation information 4, auxiliary brake operation information 5, gear change instruction lever operation information 6, and transmission gear position via the respective interfaces. Information 7 is input. The auxiliary brake is either an exhaust brake that blocks the exhaust passage of the engine, a retarder that electrically brakes the axle rotation, regenerative braking by a generator installed in the engine, or a combination thereof, and is installed near the steered wheels. It is turned on and off by the driver operating the switch.

From this program control circuit 10,
A fuel supply amount control signal 8 is sent to the engine governor 11, a control signal 9 is sent to the clutch actuator 12, and a transmission actuator control signal 14 is sent to the transmission actuator 13 via an interface. Further, this device is provided with a display device 15 at the driver's seat, and this display device 15 is connected to the program control circuit 10 via an interface. Then, the number of gears of the currently used transmission gear is displayed on the display unit 15 by numbers, the number of gears that can be shifted up is indicated by the upward arrow, and the number of gears that can be shifted down are indicated by the downward arrow. Incidentally, this embodiment is an example applied to a large towing vehicle, and this transmission is equipped with transmission gears of 16 forward gears and 2 reverse gears.

In the device thus constructed, when the driver tries to start the vehicle from the stopped state, the driver depresses the clutch and shifts the gear shift instruction lever from the neutral position (N) to the drive position (D). Program control circuit 10
Refers to the output information 3 of the gradient sensor and selects the optimum transmission gear according to the gradient. When the vehicle is on a flat road surface, one of the three to six speed change gears is selected as the start gear. When the driver recognizes the selected gear on the display unit 15 and wants to start from a lower gear because the load capacity of the towed vehicle is large, if the gear change instruction lever is operated from the D position to the DOWN position once, for example, Is downshifted one step. When the gear shift instruction lever is released, it automatically returns to the D position. Further, when it is desired to select a transmission gear lower than the transmission gear displayed on the display unit 15, for example, if the transmission instruction lever is operated twice to the DOWN position, the transmission gear is shifted up by two steps. When the start gear is set, the driver can start by gently pulling out the clutch pedal while depressing the accelerator pedal.

When the vehicle starts moving, the automatic transmission thereafter determines from the vehicle speed information, the engine rotation information, the output information of the gradient sensor, the accelerator operation information, etc., and automatically shifts up the transmission gears sequentially. Acceleration takes place. At this time, the driver does not have to step on the clutch pedal each time. The clutch actuator 12 automatically disengages the clutch under the control of the program control circuit 10, the transmission actuator 13 automatically selects and sets the transmission gear under the control of the program control circuit 10, and the clutch actuator 12 automatically Set the clutch to the contact state and control it. It is not necessary to adjust the amount of depression of the accelerator pedal according to the gear shifting operation, and the program control circuit 10 automatically controls the engine governor 11 in accordance with the gear shifting operation.

The shift control, which is a feature of the present invention, will now be described. FIG. 2 is a flow chart for explaining the main part of the control logic of the program control circuit of the apparatus of the present invention. It is assumed that a state of downshifting occurs during traveling. This is either the case where the shift down is automatically started when the vehicle speed is increasing even though there is no instruction to increase the speed from the accelerator pedal, or the case where the shift down is instructed by the operation of the shift instruction lever. The case may be.

At this time, the program control circuit 10 takes in the vehicle speed information 1, the engine rotation speed information 2, and the output information 3 of the gradient sensor, and the gradient is within a predetermined range (-3% in this example).
Steeper downhill, or steeper uphill than + 1%)
Is determined. If it is within this predetermined range, it is assumed that the vehicle is traveling on a flat road surface, and the shift operation is executed without correction. If the gradient is a steep downhill or a steep uphill that exceeds a predetermined range, the engine speed when the clutch is engaged is determined by the amount by which the vehicle speed increases or decreases during the period in which the gear shifting operation is executed. Is calculated as a correction value of. Then, the display of the number of shiftable steps of the display 15 is changed so that the shift gear whose corrected engine speed value is within the range from the lower limit value to the upper limit value allowed for the engine characteristic is selected, The shifting operation is executed within the range of the shiftable speed.

With this configuration, even if the vehicle speed increases during the period in which the clutch is in the disengaged state, it is estimated and the speed change gear to be the selection target is considered in consideration of the vehicle speed. Since the selection is made, it is possible to avoid an inconvenient operation such as the engine becoming abnormally high speed after the gear shifting operation is performed, or the gear shifting is not engaged during the gear shifting operation.

(Second Embodiment) FIG. 3 is a block diagram of the apparatus of the second embodiment of the present invention. In this second embodiment, when the vehicle is not equipped with a gradient sensor, the engine load,
Specifically, the gradient of the traveling road surface is estimated and calculated from the fuel flow rate of the engine and the vehicle speed information. Compared to FIG. 1 described in the first embodiment, there is no information on the gradient sensor, and the engine fuel flow rate information 20 is incorporated into the program control circuit 10. That is, the gradient of the traveling road surface is estimated and calculated from the load information of the engine, more specifically, the fuel supply information per unit time and the change of the vehicle speed.

FIG. 4 is a diagram showing the flow of information for the calculation. The vehicle acceleration calculator 21 calculates the vehicle acceleration from the change in the vehicle speed information 1 while the forward gear is being applied. The engine load calculator 22 calculates an engine load (or engine torque) from the engine rotation speed information 2 and the fuel flow rate information 20. The vehicle mass calculation unit 23 calculates the vehicle mass from the state of vehicle acceleration with respect to the engine load when the clutch is in the engaged state and the transmission gear is in the forward drive state. Since the vehicle mass does not change during traveling after the load is determined, the mass value can be held by calculating once or a few times based on the state when traveling on a flat road surface. deep. The gradient information calculation unit 24 estimates and calculates the gradient of the traveling road surface at that time from the vehicle acceleration information, the vehicle mass, and the engine load.

FIG. 5 is a conceptual diagram for explaining the logic for calculating the gradient information. That is, the horizontal axis represents the engine load and the vertical axis represents the vehicle acceleration, and the acceleration characteristic of the vehicle is drawn using the gradient as a parameter. Assuming that the vehicle is going uphill, the acceleration of the vehicle decreases with respect to the engine load generated as the gradient increases. This is the vehicle mass M
X for M ₁ , M ₂ , ... Mn and the gear ratio X
N × m pieces are prepared for the combination of ₁ , X ₂ , ..., Xm, and n × m pieces are similarly prepared for the case of downhill. This is set as a control map in the gradient information calculation unit 24 in advance. Then, the vehicle mass determines the mass Mp according to the size of the load, and when the current gear ratio is Xq, one control map (Mp,
Xq) can be taken out. Then, the road surface gradient can be estimated and calculated depending on where on the map the corresponding point of the vehicle acceleration with respect to the engine load at that time appears.

This is illustrated on the control map of (M ₁ , X ₁ ) as shown in FIG. 5, that is, the mass M ₁ and the gear comparison X ₁ , and the input value (Ex) of the engine load immediately before execution of the gear shifting operation is illustrated.
The intersection point P of the input value (Ay) of the vehicle acceleration with respect to is the value on this control map, and the gradient of about 4% corresponding to the position of this point P can be known.

This control map can be created from the engine characteristics and other logical values, but it is realistic to create it for each vehicle type based on the data obtained by actual measurement from the running characteristics of a vehicle equipped with a predetermined engine. Is. In that case, even if the logical relations of all the parameters are not clear, it is possible to create a control map sufficient for executing practical control.

After the running road surface gradient is estimated, the control is equivalent to the logic of FIG. 2 explained in the case of the first embodiment, and the engine rotation speed after the gear shifting operation is executed corresponding to the road surface gradient information. The shift gears that become abnormally high speed or abnormally low speed are excluded from the shiftable gears.

[0036]

As described above, according to the present invention, when the vehicle speed changes during the shift operation execution period, the change gear of the vehicle speed is predicted to select the speed change gear as the selection target. It is possible to prevent a phenomenon in which the engine rotation speed becomes abnormally high or abnormally low at the time when the gear shifting operation is completed, or the gear does not smoothly enter.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an apparatus according to a first embodiment of the present invention.

FIG. 2 is a main part flowchart for explaining a control operation of a device program control circuit according to the first embodiment of the present invention.

FIG. 3 is a block configuration diagram of a second embodiment device of the present invention.

FIG. 4 is a diagram for explaining the flow of information in the gradient information calculation of the device of the second embodiment of the present invention.

FIG. 5 is an explanatory diagram of a control map for calculating gradient information of the second embodiment device of the present invention.

[Explanation of symbols]

1 vehicle speed information 2 Engine speed information Output information of 3 gradient sensors 4 Accelerator operation information 5 Auxiliary brake operation information 6 Gear change instruction lever operation information 7 Gear position information for transmission 8 Fuel supply control signal 9 Clutch actuator control signal 10 Program control circuit 11 engine governor 12 clutch actuator 13 Transmission actuator 14 Transmission actuator control signal 15 Indicator 20 Fuel flow rate information 21 Vehicle acceleration calculator 22 Engine load calculator 23 Vehicle mass calculator 24 Gradient information calculator

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Claims (2)

(57) [Claims] 1. A means for automatically selecting and controlling an optimum shift gear by taking in vehicle speed information, engine rotation speed information, accelerator operation information, and shift instruction lever operation information, and shifting is performed on the selected shift gear. When the engine speed becomes abnormally high, the automatic shift control device is provided with means for prohibiting shifting to the selected shift gear, and means for recognizing the gradient of the traveling road surface and shifting operation. Means for estimating and calculating the engine rotation speed after the gear shift operation is performed by adding the vehicle speed variation due to the gradient during the execution period of, and the means for prohibiting the gear shift is the engine rotation speed calculated by the estimation and calculation means. look including a means for inhibiting the shift to shift gears becomes abnormal fast, means for recognizing the gradient of the traveling road surface, the speed change operation performed before
Engine load information, vehicle speed acceleration information, was used
Based on the transmission gear and vehicle mass information,
For each combination of stored vehicle mass and transmission gear ratio,
Running from the relationship between the engine load and vehicle acceleration
Use the map to determine the road surface slope to obtain information about the road surface slope
An automatic shift control device comprising means for estimating and calculating information . 2. The automatic shift according to claim 1, wherein the means for prohibiting the shift includes a means for prohibiting a shift to a shift gear in which the engine rotation speed calculated by the estimating and calculating means becomes an abnormally low speed. Control device.