JPH0331612Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) This invention relates to an improvement of an automatic transmission device for a vehicle equipped with an automatic constant speed traveling device.

(Background technology) In automobiles, in order to reduce gear shifting operations,
2. Description of the Related Art Automatic transmission devices that automatically shift up and down based on a preset pattern depending on driving conditions have already been widely adopted.

For vehicles equipped with such automatic transmissions, automatic constant-speed driving controls the governor of the fuel injection pump in the case of a diesel engine, for example, to keep the vehicle speed constant in order to further reduce the need for accelerator pedal operations. A device equipped with a device (auto cruise device) was filed by the applicant in 1982.
Proposed in No. 178926.

To explain this according to FIG. 4, a transmission 3 equipped with a known countershaft is attached to a diesel engine 1 equipped with a fuel injection pump 8 via a clutch 2. is linked to a rear axle (not shown).

The engine 1 includes an engine rotation sensor 7 that detects the engine rotation speed, and a fuel injection pump 8.
A governor control device 12 is provided for driving a governor 20 and controlling the fuel injection amount.

The transmission 3 includes a vehicle speed sensor 11 that detects the rotation speed of the main shaft to detect the vehicle speed, and a shift position sensor 34 that detects the gear shift position.
A gear shift device 35 for controlling gear shifting is provided.

Further, for example, a control lever of a governor 20 that is interlocked with an accelerator pedal is provided with a load sensor 10 that detects the pedal opening degree, that is, the engine load.

On the other hand, the control device 6 determines the optimal shift stage based on the detection signals of the engine rotation sensor 7 and the load sensor 10, and also outputs a signal for changing the shift based on the determination signal and the shift position based on the detection signal of the sensor 34. A shift change control circuit 6A outputs to the gear shift device 35, and an auto cruise control circuit that controls the governor control device 12 to keep the vehicle speed constant based on the detection signal of the vehicle speed sensor 11 when an on signal is input from the set switch 13. It consists of a control circuit 6B.

In addition to the set switch, the auto cruise control circuit 6B also includes a volume switch 14, a set coast switch 15, and a set axle switch 1.
6 is provided, and when the resume switch 14 is turned on, the vehicle speed is returned to the previously set speed and auto cruise control is restarted, while when the set coast switch 15 is turned on during auto cruise, the speed is decelerated, and when the set coast switch 15 is turned off, the speed is reduced. Similarly, when the set axle switch 16 is turned on during autocruise, the governor control device 12 is controlled to accelerate the vehicle, and when it is turned off during autocruise, the governor control device 12 is controlled to maintain the vehicle speed at that time. Reference numeral 17 indicates a main switch of the control device 6.

During auto-cruise, the shift change control circuit 6A calculates the engine speed N and the engine speed Ni when switching to each shift stage on the equal horsepower line on the engine characteristic map shown in Fig. 5 from the engine speed N and load T. Calculate the load Ti based on the following formula.

Ni = N × Target shift reduction ratio / Current shift reduction ratio Ti = T × Current shift reduction ratio / Target shift reduction ratio Next, engine speed for each of these shift stages
The fuel efficiency rate corresponding to Ni and load Ti is read from the map, and the shift gear with the best fuel efficiency (in this case, 5th gear) is selected. If this does not match the current shift gear, select the shift gear Outputs a signal to shift gears.

In addition, if you change the shift frequently depending on the road condition during autocruise, the driving condition will become unstable.To avoid this, once the shift is changed during partial load operation, the It is designed to maintain the gear shift.

By the way, in a vehicle equipped with such a device, when the shift change control circuit 6A downshifts to maintain a constant vehicle speed when driving up a hill during autocruise, the vehicle speed of the vehicle in front changes. There was a problem in that they could approach suddenly when the temperature was low, which was undesirable.

(Purpose of the invention) This invention was developed with the focus on these problems, and it is an automatic transmission system for vehicles that maintains the same shift gear to achieve the minimum fuel consumption regardless of road surface conditions during autocruise. For the purpose of providing.

(Disclosure of the invention) In order to achieve the above object, this invention uses an automatic transmission system for a vehicle that performs shift changes based on a preset pattern depending on the operating state of the engine, to adjust the vehicle speed as shown in Fig. 1. Automatic constant speed running means B that controls the fuel injection amount to keep it constant
and an automatic transmission means A for shifting the transmission to the optimal shift gear that provides the minimum fuel consumption calculated from the engine characteristic map at the start of the automatic constant speed traveling, and after shifting to the optimal shift gear during the automatic constant speed traveling. A limiting means C is provided to maintain the optimum shift stage until the automatic constant speed driving control is reset.

According to this, unlike before, a shift change to keep the vehicle speed constant is not performed during autocruise, for example, when driving uphill, so a situation where the vehicle suddenly approaches the vehicle in front can be avoided. Further, at the start of automatic constant speed driving control, the gear is shifted to the shift gear that provides the minimum fuel consumption and then the shift gear is restricted, so that deterioration of fuel efficiency due to maintaining the shift gear is suppressed.

(Example) This invention will be explained below according to the example shown in FIGS. 2 and 3. Note that the same parts as in FIG. 4 are given the same reference numerals.

11 is a vehicle speed sensor, 34 is a shift position sensor,
7 is an engine rotation sensor, 10 is a load sensor,
These detection signals are input to the control device 30 (microcomputer).

The microcomputer 30 mainly includes a microprocessor (central processing unit) 31, a memory (storage device) 32, and an interface (input/output signal processing device) 33.

Then, during normal driving, the microcomputer 30 determines the optimal shift stage based on the detection signals of the engine rotation sensor 7 and the load sensor 10, and uses this determination signal and the shift position sensor 3 as before.
Based on the detection signal No. 4, a signal to change the shift is output to the gear shift device 35.

On the other hand, during autocruise, the microcomputer 30 outputs a control signal to the governor control device 12 to keep the vehicle speed constant, and at the same time, at the start of autocruise control, the microcomputer 30 outputs a control signal to the governor control device 12 as shown in FIG. The most fuel-efficient shift gear that is on the equal horsepower line is calculated from the engine characteristic map, and if this differs from the current shift gear, the gear shift device 35 is operated to change the shift, and from now on, auto cruise is disabled. The shift stage is maintained until it is reset.

13 is the auto cruise set switch, 14
15 is a set coast switch, and 16 is a set accelerator switch.

Next, FIG. 3 shows a flowchart for executing control during auto cruise.

For example, when the set switch is turned on, auto cruise control is started in step 100.

In step 101, a predetermined period of time, for example 5 seconds, is waited until the vehicle speed stabilizes, and when that time has elapsed, the current engine speed N and load T are read in step 102.

In step 103, Ni and Ti are calculated from N and T when gears are shifted to each shift stage on the equal horsepower line as shown in FIG. 5, and the shift stage with the highest fuel efficiency is read out.

Then, in step 104, the above shift gear is compared with the current shift gear, and if different, the auto cruise control is temporarily stopped in step 105,
Set the accelerator opening to 0%, that is, to the idle state.

In step 106, a shift change is carried out when the rotational speeds of the main shaft and countershaft of the transmission become approximately the same (from then on, the gear is maintained at that shift position until the auto cruise is reset), and in step 107, the shift change is carried out. Restart cruise control.

On the other hand, if the current shift gear is the one with the best fuel efficiency in step 104, the shift gear is maintained at that shift gear.

Therefore, even if the engine load changes depending on the road surface conditions during autocruise, the transmission 3 is maintained at the shift gear at the start of autocruise. Compared to downshifting (in which the vehicle speed temporarily decreases despite auto-cruise control), recovery of vehicle speed is also slower, thereby avoiding a sudden approach to the vehicle in front.

Note that if you simply maintain the same shift position as when you started automatic constant speed driving control, you may end up being stuck in a driving state with an inappropriate gear ratio, resulting in poor fuel efficiency. Since the gear is changed in advance to the shift position that provides the minimum fuel consumption before starting the automatic constant speed driving control, such a problem will not occur.

(Effects of the invention) In summary, according to this invention, since no shift change is performed during autocruise, it is possible to avoid a sudden approach with a vehicle in front when traveling uphill, for example.

Furthermore, this invention also has the effect that deterioration in fuel efficiency can be avoided because the shift stage is set to achieve the minimum fuel consumption at the beginning of autocruise.

[Brief explanation of the drawing]

Fig. 1 is a diagram corresponding to claims of this invention, Fig. 2 is a schematic configuration diagram showing an embodiment of this invention, Fig. 3 is a flowchart showing an example of control operation, and Fig. 4 is a schematic configuration diagram of a conventional device. FIG. 5 is an engine characteristic map diagram. 7... Engine rotation sensor, 10... Load sensor, 11... Vehicle speed sensor, 12... Governor control device, 30... Microcomputer, 34... Shift position sensor, 35... Gear shift device.

Claims (1)

[Scope of utility model registration request] In an automatic transmission device for a vehicle that performs a shift change based on a preset pattern depending on the operating state of an engine, an automatic constant speed driving means for controlling a fuel injection amount to maintain a constant vehicle speed, and the automatic constant speed driving start A transmission means for shifting the transmission to the optimum shift gear that provides the minimum fuel consumption calculated from an engine characteristic map, and a transmission means for shifting the transmission to the optimum shift gear that provides the minimum fuel consumption calculated from an engine characteristic map, and a transmission means that shifts the transmission to the optimum shift gear that provides the minimum fuel consumption calculated from an engine characteristic map, and until automatic constant speed driving control is reset after shifting to the optimum shift gear during automatic constant speed driving. An automatic transmission device for a vehicle, comprising a limiting means for maintaining the optimum shift gear.