JPH0542577B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides an automatic transmission control for controlling an automatic transmission with an overdrive so that the rotation of the output shaft is faster than the rotation of the input shaft from the drive device of a vehicle. Regarding equipment.

[Prior Art] Conventionally, in order to improve fuel efficiency and reduce internal combustion engine noise, automatic transmissions have been equipped with an overdrive mechanism that allows the output shaft to rotate faster than the input shaft from the drive unit. A wide variety of vehicles are available. By shifting to overdrive when driving at high speed and with a small throttle opening, the internal combustion engine's rotational speed is lowered to the minimum necessary, saving fuel and reducing noise.

However, since the air density decreases when driving at high altitudes, it is necessary to increase the throttle opening of the internal combustion engine in order to obtain the same output as when driving at high altitudes.
Further, when the gear is shifted to overdrive, the gear ratio is less than 1 and the driving torque is small. Therefore, when driving at high altitudes and in overdrive, it is necessary to drive with a particularly large throttle opening, and the amount of fuel injected to the internal combustion engine is increased under high load, causing the air-fuel ratio to be lower than the stoichiometric air-fuel ratio. (hereinafter referred to as "rich").As a result, there is a problem in that the emission deteriorates.

For example, Japanese Unexamined Patent Publication No. 58-30554 discloses a technique for expanding the low gear operating range by changing the shift pattern when traveling at high altitudes. According to this technology, there are more opportunities to drive in a low gear when driving at high altitudes, so the gear ratio when driving at high altitudes increases, making it possible to drive with a relatively small throttle opening, which causes the problem of deterioration of emissions. The points can be resolved.

[Problems to be Solved by the Invention] However, when the shift pattern is changed during high-altitude driving to expand the low gear operating range, as in the above-mentioned Japanese Patent Application Laid-open No. 58-30554, the internal combustion engine is The frequency of operation in the (high rotation) state increases. Another problem was that there was a possibility of overheating, especially when the outside temperature was high, such as in summer.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an automatic transmission control device that can prevent deterioration of emissions and also prevent overheating when a vehicle equipped with an automatic transmission with an overdrive is traveling at high altitudes.

[Means for Solving the Problems] As shown in the basic configuration diagram of FIG. 1, the automatic transmission control device of the present invention, which has been made to achieve the above object, is configured such that the throttle opening is equal to or greater than a predetermined value. In an automatic transmission control device for a vehicle M2 that is equipped with an electronically controlled fuel injection device M1 that controls the amount of fuel supplied to the internal combustion engine to be equal to or less than the stoichiometric air-fuel ratio when M3; high-altitude running detection means M4 for detecting high-altitude running of the vehicle M2; and whether or not the internal combustion engine will be in an overheating state when the overdrive automatic transmission device M3 is prohibited from shifting to overdrive. overheat determining means M5 for determining whether the internal combustion engine is not in an overheating state when the high altitude driving detecting means M4 detects that the vehicle is traveling at a high altitude and prohibiting a shift to overdrive; The present invention is characterized in that it includes an overdrive prohibiting means M6 that prohibits the automatic transmission device M3 with overdrive from shifting to overdrive when it is determined that

Note that the automatic transmission with overdrive M3 may have any configuration as long as it is an automatic transmission having a normal overdrive transmission mechanism.

The high-altitude running detection means M4 is for detecting that the vehicle is running at a high altitude, and may be configured to have a separate means for directly detecting the atmospheric pressure, or may be provided with a fuel injection amount correction device for high-altitude running in advance in the vehicle. If the device is equipped, a configuration may be considered in which indirect detection is performed by monitoring the operating state of the device.

The overheat determination means M5 determines whether or not the internal combustion engine becomes overheated when shifting to overdrive is prohibited.
For example, the determination is made based on the detection result of the cooling water temperature of the internal combustion engine.

The overdrive inhibiting means M6 may prevent a shift signal for shifting to overdrive from being output to the automatic transmission with overdrive, or prevent overdrive even if such a shift signal is input to the automatic transmission with overdrive. It consists of something that prevents the drive from shifting gears.

[Function] According to the automatic transmission control device of the present invention having the above configuration, when the high-altitude driving detection means M4 detects that high-altitude driving is occurring and the overheat judgment means M5 prohibits shifting to overdrive, the internal combustion When it is determined that the engine will not overheat, the overdrive inhibiting means M6 will prevent the engine from overheating.
Automatic transmission device M3 with overdrive is prohibited from shifting to overdrive.

In this way, since the speed is not changed to overdrive, it is possible to drive with a small throttle opening even if the air density decreases when driving at high altitudes.
Therefore, one of the conventional problems is that when driving at high altitudes and in overdrive, the throttle opening increases due to the decrease in air density, which increases the fuel injection amount under high load and deteriorates emissions.
This can be prevented.

In addition, even when driving at high altitudes, if prohibiting overdrive driving may cause overheating of the internal combustion engine, shifting to overdrive is permitted, which is another problem. It also prevents the internal combustion engine from overheating due to prohibition of overdrive.

Furthermore, as in the above-mentioned Japanese Patent Application Laid-Open No. 58-30554, in which the shift pattern is changed during high-altitude driving to expand the low gear operating range, each gear (specifically, 1st and 2nd gears) , 3rd gear, and overdrive) (shown as a shift diagram) is changed so that the low gear operating range expands when driving at high altitudes, so in all driving ranges, the internal combustion Since the engine is operated at high rotational speed, it is prone to overheating.

In contrast, the automatic shift control device of the present invention only prohibits shifting to overdrive when driving at high altitudes, and only prohibits shifting to overdrive while driving at other gears (specifically, 1st to 3rd gears).
The transmission pattern will not change. Therefore, in the operating range of the other gears, the rotational speed of the internal combustion engine does not become higher than that on flat ground, making it difficult to fall into an overheating state.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 2 is an explanatory diagram showing a gasoline engine and its peripheral devices of a vehicle equipped with an automatic transmission control device according to an embodiment of the present invention.

1 is the gasoline engine body, 2 is the piston, 3
4 is a spark plug, 4 is an exhaust manifold, 5 is an oxygen sensor provided in the exhaust manifold and detects the residual oxygen concentration in the exhaust gas, 6 is a fuel injection valve that injects fuel into the intake air of the gasoline engine main body 1, and 7 is a fuel injection valve. An intake manifold, 8 is an intake air temperature sensor that detects the temperature of intake air sent to the gasoline engine body 1, 9 is a water temperature sensor that detects the temperature of gasoline engine cooling water, and 10 is for adjusting the intake air amount of the gasoline engine body 1. 11 is a throttle sensor that detects the opening degree of the throttle valve 10; 14 is an air flow meter that measures the amount of intake air; and 15 is a surge tank that absorbs pulsation of the intake air.

16 is an igniter that outputs the high voltage necessary for ignition; 17 is a distributor that is linked to a clink shaft (not shown) and distributes the high voltage generated by the igniter 16 to the spark plugs 3 of each cylinder; and 18 is a distributor A rotation angle sensor 19 is installed in the distributor 17 and outputs 24 pulse signals per one revolution of the distributor 17, that is, two revolutions of the crankshaft. 20 is an electronic control circuit, 21 is a key switch, and 22 is an overdrive automatic transmission with an overdrive that switches gear ratios in response to a shift change signal from the electronic control circuit 20. There is. Further, 26 represents a vehicle speed sensor that is interlocked with the axle and sends out a pulse signal according to the vehicle speed.

Next, the configuration of the electronic control circuit 20 and its related parts will be explained based on the block diagram of the control system shown in FIG.

30 inputs and calculates data output from each of the above sensors according to a control program, and
A central processing unit (hereinafter simply referred to as CPU) performs processing for controlling the operation of various devices, and 31 is a read-only memory (hereinafter simply referred to as ROM) in which control programs and initial data are stored.
32 is a random access memory (hereinafter simply referred to as RAM) in which data input to the electronic control circuit 20 and data necessary for calculations are temporarily read and written.
Reference numeral 33 designates a backup plan random access memory (called ``non-volatile memory'') backed up by a battery (not shown) so as to retain data necessary for subsequent operation of the internal combustion engine even when the key switch 21 is turned off. Simply back up below
RAM).

In addition, 34 to 37 are air flow meters 1, respectively.
4, a multiplexer that selectively outputs output signals from the water temperature sensor 9, intake air temperature sensor 8, and vehicle speed sensor 26 to the CPU 30; 39, an A/D converter that converts analog signals into digital signals; 40, a buffer 37; Or, Batsuhua 34, 35,
36, multiplexer 38 and A/D converter 39
Sends each sensor signal to the CPU 30 via
It represents an input/output port that outputs control signals for the multiplexer 38 and A/D converter 39 from the CPU 30.

On the other hand, 41 represents a buffer that sends the output signal of the oxygen sensor 5 to the comparator 42, and 43 represents a shaping circuit that shapes the waveforms of the output signals of the rotation angle sensor 18 and the cylinder discrimination sensor 19. The output of the throttle opening sensor 11 and the operation signal of the key switch 21 are sent to the CPU 30 through an input/output port 46 either directly or via a buffer 41 or the like.

Further, 47, 48, and 49 represent drive circuits that drive the fuel injection valve 6, igniter 16, and automatic transmission with overdrive 22 by signals from the CPU 30 via output ports 50, 51, and 52, respectively. . Also, 53 is a bus line that serves as a path for signals and data, and 54 is a CPU 30, ROM 3
1. It represents a clock circuit that sends a clock signal serving as control timing to the RAM 32, etc. at predetermined intervals.

In the gasoline engine control system of this embodiment configured as described above, the electronic control device 20
As part of its processing, it executes the following fuel supply control.

First, under normal vehicle running conditions, the load on the gasoline engine 1 is calculated from the throttle opening sensor 11 and the rotation angle sensor 18, and the optimum amount of fuel for that condition is supplied via the fuel injection valve 6. The air-fuel ratio is controlled to the stoichiometric air-fuel ratio.

Further, when the throttle opening sensor 11 is opened to a predetermined value or more due to a large load being applied to the vehicle, etc., which requires an increase in the output of the gasoline engine 1, the amount of fuel injected from the fuel injection valve 6 is set to be lower than the calculated value. A so-called power increase is performed in which the air-fuel ratio is made lower than the stoichiometric air-fuel ratio by increasing the amount.

Furthermore, when the vehicle is traveling at high altitudes, the air density at the high altitudes is low, so in order to maintain the operation of the gasoline engine 1 under the above-mentioned stoichiometric air-fuel ratio, even if the amount of intake air is the same, the air density at the high altitudes is low. The amount of fuel must be reduced. Therefore, oxygen sensor 5
If the system determines that the vehicle is traveling at a high altitude due to a decrease in the oxygen concentration in the exhaust gas based on the output of

By comprehensively executing these controls as appropriate, the gasoline engine 1 can operate favorably.

Next, a first embodiment related to overdrive prohibition control will be described.

FIG. 4 is a flowchart showing the control of the first embodiment. This routine interrupts the CPU 30 at predetermined time intervals when the key switch 21 is turned on when the gasoline engine 1 is started.

When the processing of this routine is started, step 200 is first executed to read the air-fuel ratio learning high altitude correction coefficient FG. As mentioned above, the air-fuel ratio learning high altitude correction is one of the air-fuel ratio controls executed by the CPU 30. When the vehicle is traveling at a high altitude and the density of the air sucked into the gasoline engine 1 becomes low, the air-fuel ratio becomes rich. Therefore, the air-fuel ratio learning high altitude correction coefficient FG is calculated appropriately to reduce fuel injection so that the air-fuel ratio becomes the stoichiometric air-fuel ratio. Therefore, the air-fuel ratio learning high altitude supplementary coefficient FG is calculated by the air-fuel ratio control device so as to take a larger negative value as the altitude increases.

In this step 200, the air-fuel ratio learning high altitude correction coefficient FG calculated by this air-fuel ratio control device is read.

In the next step 210, a reference value FB to be compared with the air-fuel ratio learning control correction coefficient FG, which is stored in advance in the ROM 31, is read and subjected to the processing in the next step 220.

In step 220, the air-fuel ratio learning control correction coefficient FG read in steps 200 and 210 above is set to the reference value.
It is judged whether or not it is smaller than FB, and a negative judgment is made, i.e.
If FG≧FB, the process moves to step 270, and after the process at step 270 is executed, this routine ends.

Step 270 is a process of resetting a flag F for prohibiting overdrive driving (hereinafter referred to as overdrive prohibition flag) to "0". The operation when the overdrive prohibition flag F is "1" will be described in step 260, which will be described later.

On the other hand, an affirmative judgment is made in step 220, that is, FG<FB
In this case, it is determined that the vehicle is traveling at a point above a predetermined altitude, and the next step is
At 230, the output of the water temperature sensor 9 is taken in,
The current cooling water temperature TW of gasoline engine 1 is read. Then, in the next step 240, ROM3
Reference value TB of cooling water temperature stored in advance in 1
is read, and in step 250, the cooling water temperature TW
It is determined whether or not is larger than the reference value TB.

If the determination in step 250 is affirmative, that is, TW > TB, then the coolant temperature has risen considerably, and the overdrive shift is prohibited in this state and the revolution speed of the gasoline engine 1 is further increased. Executing such control may cause overheating, and the step
Move to 270. Then, in step 270, the overdrive prohibition flag F is reset to "0", and this routine ends.

Also, a negative judgment is made at step 250, that is, TW≦TB
If it is determined that this is the case, it is determined that there is no possibility of overheating even if control is executed to prohibit overdrive shifting and further increase the engine speed in this state, and in step 260 overdrive is changed. The prohibition flag F is set to "1" and this routine ends.

If the overdrive prohibition flag F is set to "1", the rotational speed of gasoline engine 1 and throttle 1 are controlled in other automatic shift control routines.
Based on the opening degree of 0, even if it is determined that the automatic transmission with overdrive 22 is in a state of shifting to overdrive, a signal to shift the automatic transmission with overdrive 22 to overdrive is not output.

According to the first embodiment, when the vehicle is traveling at a high altitude and the air density falls below a predetermined value (step
220: YES), and when it is determined that the internal combustion engine will not become overheated if the shift to overdrive is prohibited (Step 250: NO)
Only then is the above-mentioned overdrive prohibition process (that is, setting the overdrive prohibition flag F to "1") executed.

In this way, since the speed is not changed to overdrive, it is possible to drive with a small throttle opening even if the air density decreases when driving at high altitudes.
Therefore, one of the conventional problems was that when driving at high altitudes and in overdrive, the throttle opening becomes large due to the decrease in air density, and the amount of fuel injection is increased under high load, resulting in poor emissions. ” can be prevented.

In addition, even when driving at high altitudes (step 220: YES), if prohibiting overdrive driving may cause overheating (step 250: YES), shifting to overdrive is permitted (step 220: YES). 270), it is also possible to prevent the internal combustion engine from overheating due to prohibition of overdrive.

Next, a second embodiment related to overdrive prohibition control will be described.

FIG. 5 shows the control flowchart. Like the first embodiment, this second embodiment is also applied to the control system of the gasoline engine 1 shown in FIGS. 2 and 3.

This routine includes a step in which throttle opening information is taken in and determined in the first embodiment shown in FIG.
This is an addition of steps 360 to 380.

Steps 300 to 350, steps 390, and 400 of this routine shown in FIG.
The same processing as steps 200 to 270 in the first embodiment shown in the figure is executed.

Therefore, in the second embodiment, steps 360 to 360 are performed when the vehicle is traveling at a high altitude and the water temperature has not yet risen to the point of overheating.
The process in step 390 is executed, and in other cases, the overdrive prohibition flag F is reset in step 400.

In step 360, the throttle opening sensor 11
The current throttle opening information SO is taken in,
In step 370, the throttle opening reference value SB, which is previously stored in the ROM 31, is read. Then, in the following step 380, it is determined whether the current throttle opening information SO is greater than or equal to the reference value SB.

Then, only when the condition of SO≧SB is satisfied (step 380: YES), the next step 390 is executed and the overdrive prohibition flag F becomes “1”.
is set, and this routine ends.

On the other hand, in other cases, the overdrive prohibition flag F is reset to "0" in step 400, and then this routine is ended.

According to the second embodiment, when driving at high altitude (step
320: YES), and even if it is determined that the internal combustion engine will not overheat based on the water temperature (Step 350: NO), overheating will occur only when the throttle opening is large (Step 380: YES). A process for prohibiting the drive from changing gears is executed.

Therefore, during steady driving with a small throttle opening, overdrive driving is possible, and the intended purpose of overdrive driving, such as improving fuel efficiency and reducing noise, can be achieved. Overdrive shifting is prohibited only when the possibility of overdrive is extremely high and the CO concentration is high.

Next, a third embodiment related to overdrive prohibition control will be described.

FIG. 6 shows the control flowchart. The third embodiment is an overdrive prohibition control that further takes into account the vehicle speed as an item to monitor the operating state of the gasoline engine 1 in addition to the control of the second embodiment.

This routine is added to the second embodiment shown in FIG.
This is an addition of step 610.

Steps 500 to 580, steps 620, and 630 of this routine shown in FIG.
This corresponds to steps 300 to 400 in the second embodiment shown in the figure, and the same processing is executed.

Newly added steps 590 to this routine
To explain step 610, we will first explain step 610.
At step 590, the current vehicle speed VR is fetched from the vehicle speed sensor 26, and at step 600, the vehicle speed reference value VB previously stored in the ROM 31 is read. Then, in the following step 610, it is determined whether the current vehicle speed VR is greater than the reference VB.

Then, only when VR≦VB (step 610: NO), the next step 620 is executed, the overdrive prohibition flag F is set to "1", and this routine ends.

On the other hand, in other cases, the overdrive prohibition flag F is reset to "0" in step 630, and then this routine is ended.

According to the third embodiment, the added step
The processing from step 590 to step 610 produces the following effects.

That is, in the second embodiment described above, when driving at high altitudes and the water temperature is low, overdrive driving is always prohibited if the throttle opening is above a predetermined value, but even in such a case, the vehicle speed is further reduced. VR
Overdrive driving is prohibited only when VB is below a predetermined value (VB).

In this way, the overdrive driving prohibition is executed by detecting a state in which the throttle opening is above a predetermined value and the vehicle speed VR is low, that is, a sudden acceleration state, so the driver can prevent sudden acceleration that requires a large output torque. When accelerating, you will feel that the controllability is good due to the shift that is not overdrive driving. When the gasoline engine 1 reaches a high rotation speed at a predetermined speed or higher, by canceling this overdrive prohibition, the gasoline engine rotation speed decreases, and even better gear shift control is possible without the possibility of overheating. It is.

The present invention is not limited to these embodiments in any way, and may be implemented in various forms without departing from the gist of the present invention.

[Effects of the Invention] As described in detail above, according to the automatic shift control device of the present invention, when it is determined that the internal combustion engine will not be in an overheating state when traveling at high altitude and the shift to overdrive is prohibited, Since shifting to overdrive is prohibited, it is possible to prevent a vehicle equipped with an automatic transmission with an overdrive from deteriorating the emission when traveling at high altitudes, and also to prevent overheating.

[Brief explanation of the drawing]

Fig. 1 is a basic configuration diagram of the present invention, Fig. 2 is a schematic diagram of a control system for a gasoline engine of a vehicle equipped with an automatic transmission control device according to an embodiment, Fig. 3 is a block diagram of the control system, and Fig. 4 5 shows a flowchart of the first embodiment, FIG. 5 shows a flowchart of the second embodiment, and FIG. 6 shows a flowchart of the third embodiment. M1...electronically controlled fuel injection device, M2...vehicle, M3...automatic transmission with overdrive,
M4...High altitude driving detection means, M5...Overheat judgment means, M6...Overdrive prohibition means, 1...Gasoline engine, 6...Fuel injection valve, 9...Water temperature sensor, 11...Throttle opening sensor, 22... Automatic transmission with overdrive, 26... Vehicle speed sensor.

Claims (1)

[Claims] 1. When the throttle opening reaches a predetermined value or more,
An automatic transmission control device for a vehicle equipped with an electronically controlled fuel injection device that keeps the amount of fuel supplied to the internal combustion engine below the stoichiometric air-fuel ratio, comprising: an automatic transmission with an overdrive that varies the traveling speed of the vehicle; a high altitude driving detection means for detecting driving; an overheat determination means for determining whether or not the internal combustion engine is in an overheating state when the automatic transmission with overdrive is prohibited from shifting to overdrive; When the traveling detecting means detects that the vehicle is traveling at a high altitude and the overheat determining means determines that the internal combustion engine will not become overheated when shifting to overdrive is prohibited, the automatic transmission with overdrive An automatic shift control device comprising: overdrive prohibition means for prohibiting shifting to overdrive;