JP2003329124A - Transmission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the temperature of an engine coolant from increasing to an abnormally high value, while executing a shift-down operation when a driver travels at a low speed on a road of a long ascending slope by relying on control of a transmission control device. <P>SOLUTION: Under a condition that an engine revolution speed is at a value allowing shift down, and accelerator opening at a predetermined value or more is continued over a predetermined period, and under other conditions, the shift down is automatically executed by interrupt control even if a driving operation is not executed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an automatic transmission of an automobile. The present invention relates to improvement of downshift control by an automatic transmission. The present invention is for preventing a vehicle traveling on a long uphill from continuing to operate without performing downshifting and increasing the engine temperature.

The term "automatic transmission" as used herein refers to selection control of a combination of transmission gears set stepwise by arithmetic control, using information including engine rotation or accelerator opening as an input, even without a driver's operation. A device that does.
This "automatic transmission" is a transmission that automatically selects a transmission gear according to input information, and is equipped with a transmission lever for selecting the transmission gear by operation, or by opening and closing the clutch by operation. The so-called semi-automatic control system is equipped with a clutch pedal for operating the vehicle, and the driver can operate these to interrupt the control automatically executed by the control device and perform gear shifting operation by the operation. Type transmission is also included in the category.

[0003]

2. Description of the Related Art Automatic transmissions have come to be widely used in commercial vehicles such as lorries and buses. In a commercial vehicle, the weight of the vehicle fluctuates greatly depending on the cargo loading state or the number of passengers, so it is practically difficult to design the automatic shifting operation to satisfy the driver under all conditions. . In particular, many commercial vehicle drivers are skilled in driving as a profession, and instead of relying on the control of an automatic transmission for all gear shifting operations, they select their gears or use clutches.・
A device capable of performing a fine driving operation by operating a pedal is preferred. Therefore, even in a device configured so that the clutch is automatically disengaged by hydraulic control in accordance with a gear shift operation, the clutch pedal is provided, and the automatic control interrupt control controls the clutch operation. A device configured so that it can be disengaged or controlled to a half-clutch state by the operation of has become widespread.

In many of these devices, the gear shift lever can be operated to instruct UP and DOWN in addition to N (neutral), D (drive) and R (reverse). An example of the shift state of the shift lever is shown at the left end of FIG. 1, which is a reference drawing of an embodiment device described later. That is, when the shift lever is operated and set to the D (drive) position, the optimum gear ratio is selected and set from the information of the engine rotation and the accelerator pedal opening at that time by the automatic control of the shift control device. It In this state, if the driver operates the shift lever to the UP position or the DOWN position without stepping on the clutch pedal, the shift control device automatically lowers the fuel supply amount to the engine, disengages the clutch, and shifts the shift gear. Is upshifted or downshifted according to the instruction of the shift lever, and when the shift gear is changed, the operation of automatically engaging the clutch is executed. Even if there is no change in the depression amount of the accelerator pedal during the period in which the shift operation is executed, the control device executes the control so as to properly adjust the fuel supply amount to the engine in accordance with the engagement and disengagement of the clutch. . In addition, the driver can change the speed change lever to DOWN.
If the position is operated twice at short intervals, the transmission gear is downshifted by two steps while the clutch is disengaged. Such an operation is also possible.

In a vehicle equipped with such a shift control device, in a steady running state, depending on the slope of the running road surface,
That is, an appropriate shift gear is selected and set by calculation according to the state of the vehicle speed and the engine load to run. At this time, in many control devices, the control logic is selected so as to maximize the fuel efficiency of the engine in accordance with the accelerator opening at that time.

[0006] Further, some vehicles sold in recent years have a structure in which an automatic transmission is provided with a manual mode and can be switched by a switch operation. When the normal auto mode is set, the automatic gear shift control is executed from the information on the engine rotation and the accelerator pedal opening as described above, but when the driver sets the manual mode by operation, the automatic shift control starts from that point. After that, until the manual mode is released, the automatic selection operation of the transmission gear is prohibited, and the U of the transmission lever is set by the driver.
It follows the operation instruction of P or DOWN. An example of the manual mode setting operation is to provide an H (hold) position at the position of the shift lever as shown at the left end of FIG. When the shift lever is set to the H (hold) position, the automatic shift operation by the transmission control device is prohibited.

[0007]

The inventors of the present application have conducted tests to design the above-mentioned device to a new standard. Among them, when traveling on a long uphill with a large cargo load, everything depends on automatic control,
I have noticed that the temperature of the engine coolant may rise. When the coolant temperature rises, the cooling capacity of the radiator is automatically controlled accordingly, and when the coolant temperature rises, the fuel flow rate to the engine is controlled automatically. Therefore, in practice, it will not overheat immediately. However, if the fuel flow rate is limited, there will be inconveniences such as a poor feeling of climbing and a decrease in the fuel consumption rate.

Upon further study of this phenomenon, the control state that causes such a phenomenon is set so that the control logic maintains an optimum fuel efficiency state with respect to the accelerator opening that is being operated at that time. It turned out that it occurs because it is being done. Furthermore, such a phenomenon happens to occur when the vehicle runs at a low speed after the preceding vehicle that is climbing uphill, and it is impossible to overtake, and it is necessary to follow the speed of the preceding vehicle for a long time. It has also been found that it often occurs when in a critical state.

When the engine coolant temperature is rising in this way, the driver operates the speed change lever to shift down without depending on automatic control of everything, and even if the traveling speed is the same. By increasing the engine speed, it is possible to prevent the coolant temperature from further increasing. This is because by increasing the engine speed, the wind speed sent to the radiator is increased and the cooling capacity is improved. However, not all drivers perform such driving operations. Considering that some drivers may continue to run for a long time without noticing the rise in the temperature of the engine coolant, it has come to be considered that some design measure is necessary.

Further, as described above, in the device constructed so that the automatic shift control can be prohibited by the operation and all the trains can be operated by the manual operation, after the driver sets the manual state, it is long. It has been found that the phenomenon in which the engine coolant temperature rises may also occur when low-speed running is continued without properly performing a downshift operation on an uphill. The inventors of the present application have decided to adopt a design that avoids a rise in the coolant temperature even in such an improper operation.

The present invention has been made against such a background, and even when the driver does not properly perform the downshift operation while traveling on a long uphill at a low speed, the engine is not properly operated. An object of the present invention is to provide a control device that avoids an increase in the coolant temperature. SUMMARY OF THE INVENTION It is an object of the present invention to provide a device capable of avoiding an increase in engine coolant temperature even when a low speed running is continued for a long time in a special state that depends on the control of an automatic transmission. To do. The present invention provides a control device in which the coolant temperature does not rise even if the driver sets the automatic transmission in a manual state and runs at low speed for a long time without performing appropriate shift control. The purpose is to do.

[0012]

SUMMARY OF THE INVENTION The present invention provides a transmission control device for selectively controlling a transmission gear using information including engine rotation (ω) and accelerator opening (α) as input.
Even if there is no downshift operation, (i) the engine speed is a value that allows downshifting, and (ii) the state in which the accelerator opening is equal to or greater than the predetermined value α ₀ continues for a predetermined time t It is characterized by including means for automatically performing a downshift. Where the above conditions
(i) and (ii) are indispensable conditions. The present invention can be implemented even if the control logic is configured by adding a condition other than this condition. That is, the present invention can be implemented by using information other than engine rotation and accelerator opening as input information and adding control according to the input information.

As examples of conditions that can be added in addition to the above conditions, (iii) the engine coolant temperature (θ) is in a predetermined high temperature state, (iv) the change in accelerator opening (Δα) over t minutes. Is within a predetermined range, (v) the clutch pedal is not operated, and (vi) the vehicle speed (V) is below a predetermined value. It is appropriate that the time t in the condition (iv) is the same value as the time t in the condition (ii), but different values can be set.

"The engine rotational speed is a value that can be downshifted" means that the engine after the downshift is maintained even if the transmission is downshifted by n stages (n is an integer of 1 or more) and the traveling speed is continued. It means that the rotation speed is currently in the range of rotation speed that can stably generate the required output. This is a value that is determined for each vehicle type from the engine characteristics of each vehicle and each gear ratio of the transmission. More specifically, the control logic will be described. According to each gear ratio of the transmission, a range of engine rotation speeds that can be supported from engine characteristics, that is, a range of vehicle speeds that can be supported is determined and stored as a table in the control device. Then, it is determined whether or not the downshift is possible by referring to this table during the shift operation.

The predetermined value α _{0 of the} accelerator opening and the predetermined time t are selected according to the characteristics of the vehicle. It is especially desirable to select from the results of running tests. As an example of a vehicle tested by the inventors of the present application, the predetermined value α ₀ of the accelerator opening may be selected to be 35% to 75%, and more preferably 40% to 60%. Further, exemplifying the predetermined time t is 2
It takes about 8 to 8 minutes.

Specific numerical values for the above conditions (iii) to (vi) should be determined from the vehicle characteristics in each design. For reference, here are these numerical values, and the engine coolant temperature (θ) is 90
When the temperature exceeds the value set between 0 ° C and 95 ° C, the high temperature state can be obtained. Regarding the change (Δα) in the accelerator opening, up to about ± 5% can be set as the predetermined range. About vehicle speed (V) 35km / h to 60km
A value selected in the range of / h can be used as the predetermined value.

Another feature of the present invention is to implement it in a device which can set a manual mode in which an automatic shifting operation is prohibited by an operation. This is configured to include means for automatically performing downshifting according to the condition (i) and the condition (ii) even when a manual mode for prohibiting an automatic gear shift operation is set by operation. Is. Similarly, the conditions (iii) to (vi) can be added as conditions.

With this configuration, even when the engine coolant temperature rises, the driver does not notice this even when the vehicle is traveling at a low speed on a long uphill road surface, and the downshift operation is executed. Even when not performed, it is possible to avoid the occurrence of other inconvenient phenomenon that the engine output decreases.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION First, an outline of an automatic transmission according to the present invention will be described with reference to FIG. This example relates to the semi-automatic transmission described above.

The rotation output of the engine 1 is transmitted to the transmission 3 via the clutch 2 and further transmitted from the propeller shaft 4 to an axle (not shown). Fuel injection pump 5 of engine 1
Is an engine EC composed of a program control circuit
Controlled by U6. The clutch 2 of this device is a so-called mechanical clutch, and its engagement / disengagement operation is controlled by a clutch actuator 37. In this example, the transmission 3 is a mechanical type having seven forward gears and one reverse gear, and is controlled by the shift unit 7 in the XY directions. This clutch
The actuator 37 and the shift unit 7 are controlled by the air pressure supplied from the air tank 8. The air pressure supplied to the clutch actuator 37 is controlled by the clutch control valve 9. Shift unit 7
Has X direction (shift) and Y direction (select) inside
The control valves of the
Air pressure is supplied to each of the cylinder and the select cylinder. The clutch control valve 9 and the control valve built in the shift unit 7 are electrically controlled by a transmission control device 10 constituted by a program control circuit. The present invention is implemented in the transmission control device 10, and is implemented by adding the control logic of the transmission control device 10.

The clutch 2 is controlled by the clutch actuator 37 as well as the clutch pedal 11
A hydraulic pump 12 driven by means of a hydraulic system 13 allows direct mechanical control via a hydraulic system 13.
That is, when the clutch 2 is in the connected state, the driver can perform the connection / disconnection control including the half clutch by stepping on the clutch pedal 11 in the driver's seat. Utilizing the clutch control by this clutch pedal 11,
When the vehicle starts from a stopped state, the driver can perform control by his / her clutch operation without depending on the control of the automatic clutch. The clutch connection / disconnection operation by the clutch pedal 11 has priority over the clutch control by the transmission control device 10. Generally, the clutch operation by the clutch pedal 11 is often used only when starting the vehicle, that is, when starting the vehicle from a state where the vehicle speed is zero.
As described above, the driver of this type of commercial heavy vehicle is generally a professional driver, and does not find it troublesome to control the connection state of the clutch with his / her left foot when starting. Rather, the delicate clutch control in the low gear at the time of starting is performed by itself as desired, and the smooth starting can be performed, so this device is popular with the driver. And
By performing clutch control with the driver's left foot when starting, it is possible to save fuel consumption and reduce the amount of exhaust gas.

Returning to the explanation of the configuration shown in FIG. 1, the clutch pedal 11 is interlocked with the operation of the clutch pedal 11.
Clutch switch 1 to detect that the vehicle is in the released state
4 and a clutch switch 15 for detecting the depression of the clutch pedal 11 are provided, and the detection outputs of these are input to the transmission control device 10. The accelerator pedal 16 is provided with an accelerator position sensor 17, whose output is taken into the engine ECU 6.

The state of the speed change lever 18 provided in the driver's seat is taken into the transmission control device 10. The gear shift lever 18 has an N line as shown at the left end of FIG.
It can be set to four positions of range (neutral position), D range (drive position), H range (hold position), and R range (retracted position). Here, the H range is for temporarily prohibiting the shift control of the transmission control device 10 by a driver's operation, and is an operation position for setting the manual mode described above.

When the gear shift lever 18 is set to the D range at the time of starting, all the gear selection settings after starting are automatically executed by the control of the transmission control device 10. For example, when the shift lever 18 is shifted to the D range and the vehicle is started, the second speed is selectively set when the vehicle speed is zero, and after the vehicle is started, the shift gear is automatically shifted up according to the acceleration state. Go on. Each time the shift gear is changed, the clutch 2 is repeatedly connected and disconnected under the control of the transmission control device 10, and the fuel flow rate supplied to the engine 1 is adjusted in synchronization with the connection and disconnection.

Further, when the speed change lever 18 is in the H range (hold position), by operating the lever up or down, the driver shifts up or down exceptionally for automatic gear selection. It is possible to instruct downshift. This operation can be performed upshift or downshift by two steps by shaking upshift or downshift twice. Also at this time, the clutch 2 is automatically disengaged, the gear shift is executed, the clutch 2 is controlled to be automatically connected, and the fuel flow rate is automatically adjusted.

The vehicle speed information is taken into the transmission control device 10 from a vehicle speed sensor 35 which detects the rotation of the propeller shaft 4. In order to detect the state of the transmission 3, the transmission 3 is provided with a counter shaft rotation sensor 36, and this output information is taken into the transmission control device 10.

The auxiliary construction of FIG. 1 will be further described. The transmission control device 10 is connected to the engine ECU 6 by a communication bus 34. And engine ECU
6 is also connected via the communication bus 34 to the monitor interface 20 and the display 21 arranged in the driver's seat. Further, the transmission control device 10 is connected to an operation switch 22 arranged in the driver's seat, and the transmission control device 10 is connected to an alarm buzzer 23 arranged in the driver's seat. The transmission control device 10 receives an operation input of the emergency operation end 24 arranged at the driver's seat. The operation switch 22, the alarm buzzer 23, and the emergency operation end 24 are used when the operation of the transmission control device 10 is in an abnormal state, and their configurations and operations are directly related to the present invention. Since it does not exist, a more detailed description is omitted here.

The transmission controller 10 includes an air tank 8
The state information of the pressure sensor 25 is fetched. This is the emergency valve 2 when the air pressure in the air tank 8 drops.
The control signal is sent to 6 to utilize the emergency air pressure 27, and the reliability of the automatic transmission is improved. In addition to this, the transmission control device 10
Includes status information 28 of the PTO (Power Take Off) device,
State information 29 of the retarder device, state information 30 of the brake control system, state information 31 of the exhaust brake control system, brake pressure information 33 and the like are fetched.

The transmission control device 10 includes an engine ECU.
Information on the engine load factor is fetched from 6. The engine load factor is defined as the ratio of the engine output torque at that time to the maximum engine output torque that can be output depending on the engine speed at that time. This calculation is performed by the engine ECU 6, is taken into the transmission control device 10 via the communication bus 34, and is used as information for selection control of the transmission gears.

The shift control of the transmission control device 10 will now be described. The transmission control device 10 inputs information on the output of the vehicle speed sensor 35, the output of the position sensor 17 of the accelerator pedal 16 and the engine load factor. According to, the software for selecting the optimum gear is set. When the accelerator pedal 16 is depressed greatly in the steady running state, the downshift gear is automatically selected and set. When the vehicle changes from a steady running state to an uphill state, the shift down gear is automatically selected and set according to the output of the vehicle speed sensor 35, the information of the engine load factor and the output of the accelerator position sensor 17.

Here, the features of the present invention are that, in the control logic of the transmission control device 10, (i) the engine rotational speed is a value that allows downshifting, and (ii) the accelerator opening is a predetermined value α. It is configured so as to include means for automatically performing a downshift even if there is no downshift operation, provided that the state of ₀ or more continues for a predetermined time t. That is, while the driver should normally perform the downshift operation while traveling on a long uphill at a low speed, when the time elapses without the downshift operation being performed, the shift of the present invention is performed. The machine control device 10 is configured to forcibly execute the downshift. In the apparatus of this embodiment, the above condition (i)
In addition to (ii) and (ii), the engine coolant temperature is in a predetermined high temperature state, (iv) the accelerator opening is within a predetermined range for t minutes, and (v) the clutch pedal is not operated. (Vi) When all the conditions that the vehicle speed is equal to or lower than a predetermined value are satisfied, the transmission is controlled to be downshifted by one gear regardless of the driving operation.

Further, in the device of the present invention, when the speed change lever 18 is set to the H (hold) position and the vehicle is also traveling uphill for a long time, the driving operation prohibits the speed change operation. Even in the hold state, the control is performed so as to forcibly execute the downshift.

FIG. 2 shows a flow chart of the main part of control according to the embodiment of the present invention. That is, the transmission control device 10 identifies whether the accelerator opening is 50% or more according to the input information, and sequentially executes the condition determination of the present invention when the accelerator opening is 50% or more. The history information of the accelerator opening is taken in and it is identified whether the change is within 5%. Then, the engine rotation information is fetched and it is determined whether the rotation speed can be shifted down by referring to the map. Further, the vehicle speed information is fetched to identify whether the vehicle speed is 50 km / h or less. Further, when it is identified that the clutch pedal is not operated and the coolant temperature is 95 ° C. or higher, the interrupt control is executed to execute the downshift of the predetermined number of steps (one step in this embodiment apparatus).

[0034]

As described above, according to the present invention, when the vehicle is traveling on a long uphill at a low speed, the engine coolant temperature is prevented from increasing even if the driver does not properly perform the downshift operation. It can be avoided. According to the present invention, even if the driver sets the automatic transmission to the manual state and then runs at a low speed for a long time without performing appropriate shift control, the coolant temperature does not rise.

[Brief description of drawings]

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

FIG. 2 is a control flowchart of a main part of the apparatus according to the embodiment of the present invention.

[Explanation of symbols]

1 engine 2 clutch 3 transmission 4 propeller shaft 5 Fuel injection pump 6 engine ECU 7 shift units 8 air tanks 9 Clutch control valve 10 Transmission control device 11 clutch pedal 12 hydraulic pump 13 Hydraulic system 14 Clutch switch (upper end) 15 Clutch switch (bottom end) 16 accelerator pedal 17 Accelerator position sensor 18 gear shift lever 19 blinker switch 20 monitor interface 21 Display 22 Operation switch 23 Alarm buzzer 24 Emergency operation end 25 Pressure sensor 26 Emergency valve 27 Emergency air pressure 28 PTO equipment information 29 Retarder information 30 Brake control system information 31 Exhaust brake control system information 32 Brake status information 33 Brake pressure information 34 Communication Bus 35 vehicle speed sensor 36 counter shaft rotation sensor 37 Clutch / Actuator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16H 59:78 F16H 59:78

Claims (3)

[Claims] 1. A transmission control device for selectively controlling a transmission gear by inputting information including an engine rotation (ω) and an accelerator opening (α), (i) the engine rotation speed is a value that can be downshifted, (Ii) a means for automatically performing a downshift even if there is no downshift operation provided that the state in which the accelerator opening is equal to or greater than a predetermined value α ₀ continues for a predetermined time t Transmission control device. 2. In addition to the above conditions (i) and (ii),
(iii) The engine coolant temperature is a predetermined high temperature state, (iv) The accelerator opening is within a predetermined range for t minutes, (v) The clutch pedal is not operated, (v)
i) The transmission control device according to claim 1, wherein one or a plurality of vehicle speeds are equal to or lower than a predetermined value. 3. The transmission control device according to claim 1, further comprising means for automatically performing a downshift under the above condition even when a manual mode for prohibiting an automatic gearshift operation is set by an operation.