JPH10129305A - Speed controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve responsiveness and an acceleration property by providing an engine target rotational speed correcting means which gives an engine target rotational speed on an engine target rotational speed increase curve at an elapsed time to a speed ratio controlling means. SOLUTION: From a sensor, an engine rotational speed nE, an output shaft rotational speed nO, an accelerator pedal displacement (x), and an engine brake switch on/off condition (y) are sequently inputted into a controller 13. Subsequently, on the basis of a predetermined corresponding relationship between the accelerator pedal displacement (x) and the engine target rotational speed NE(x), an engine target rotational speed NE(x) matching with the present accelerator pedal displacement (x) is obtained. At a certain elapsed time (t), if the target rotational speed NE(x) exceeds the upper limit value, the upper limit value is outputted as a target rotational speed NE. If the target rotational speed NE(x) is the upper limit value or less at a certain elapsed time (t), the target rotational speed NE(x) is outputted as the engine target rotational speed NE.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle equipped with a continuously variable transmission or a mechanism equivalent thereto, which is operated in response to an operation of an accelerator operator for indicating an engine target rotational speed. The present invention relates to a vehicle speed control device for controlling a speed ratio of a step transmission or a parameter corresponding thereto.

[0002]

2. Description of the Related Art Generally, in a vehicle equipped with a continuously variable transmission, an accelerator pedal as an accelerator operator indicates an engine target rotation speed corresponding to an operation position (accelerator depression amount). When the actual engine speed is higher than the engine target speed indicated by the accelerator pedal, the speed ratio of the continuously variable transmission (the reciprocal of the reduction ratio: When the actual engine speed is lower than the engine target speed indicated by the accelerator pedal, the speed ratio decreases in accordance with the deviation between the two speeds. Output a control signal for changing the speed ratio to the continuously variable transmission so that the speed ratio is changed and the actual engine Rotation speed is controlled to match the target rotational speed.

However, when the above-described control is performed using an engine target rotation speed set in advance in accordance with the accelerator pedal position, the following problems occur.

[0004] That is, 1) When the accelerator pedal is depressed, only the target value of the engine speed increases, so that the speed ratio decreases, and the engine is accelerated by the inertia energy of the vehicle body. The driver will behave differently from the driver's intention to temporarily decrease.

On the other hand, Japanese Patent Publication No. 5-43862 measures the actual rate of increase of the engine speed, and when the rate of increase is equal to or higher than a set value, the above-described normal control is stopped and (increased). A method is shown in which the speed ratio is changed in a direction that suppresses an increase in the engine rotation speed by an amount proportional to the (ratio-set value).

However, in this method, since there is only one set value regardless of the value of the engine speed, the set value is too large in an area where the engine speed is high, and the engine speed overshoots, and the vehicle speed increases. There was a problem in terms of acceleration.

2) When the accelerator pedal is released,
Only the target value of the engine rotational speed decreases, so that the speed ratio increases, and the vehicle body is temporarily accelerated by the inertia energy of the engine, so that the driver performs a motion different from the driver's intention.

Also, by returning the accelerator pedal,
There are times when it is desired to apply the engine brake, but the control described above causes a movement contrary thereto. vice versa,
By returning the accelerator pedal, there is a case where it is desired that the vehicle coasts without applying the engine brake and travels with good fuel efficiency.

On the other hand, in Japanese Patent Application Laid-Open No. 60-95254, if the return speed when the accelerator pedal is released is faster than a set value, the target engine speed is increased to apply the engine brake. I have to.

However, in this method, the control changes on and off depending on whether or not the accelerator pedal is returned faster than a set value. Therefore, there is a possibility that the engine brake is applied but the engine brake is not applied.

Further, if the effectiveness of the engine brake is constant irrespective of the speed of the vehicle, the controllability of the vehicle speed may not be good.

The present invention has been made in view of such circumstances. 1) When the accelerator pedal is depressed, the vehicle speed is increased according to the driver's intention, and regardless of the engine speed, A first object is to improve responsiveness and acceleration.

2) A second object is to reduce the vehicle speed according to the driver's intention when returning the accelerator pedal.

3) A third object of the present invention is to enable coasting when it is not desired to apply the engine brake when returning the accelerator pedal.

4) When it is desired to apply the engine brake when the accelerator pedal is released, the degree of the effect of the engine brake changes at each return speed of the accelerator pedal, and the degree of the effect of the engine brake varies according to the operator's intention. Is the fourth object.

5) A fifth object is to improve the controllability of the vehicle speed by changing the effectiveness of the engine brake according to the vehicle speed when returning the accelerator pedal.

[0017]

Therefore, in order to achieve the first object, in the first invention of the present invention,
An accelerator operator for instructing an engine target rotational speed corresponding to the operation position, and a driving force of the engine are transmitted, and a speed ratio of the output shaft rotational speed to the engine rotational speed is continuously changed based on a given control signal. A continuously variable transmission, rotation speed detection means for detecting an actual rotation speed of the engine, and an actual engine rotation speed detected by the rotation speed detection means based on the given engine target rotation speed. When the engine speed is higher than the target engine speed, the speed ratio is increased in accordance with the deviation between the two engine speeds, and the detected actual engine speed is lower than the given engine target speed. Sometimes, a control signal for changing the speed ratio is output so that the speed ratio decreases in accordance with the difference between these two rotation speeds. A vehicle speed control device comprising a speed ratio control unit, wherein the setting unit sets an engine target rotation speed increase curve indicating an engine target rotation speed that increases and changes according to elapsed time, and is instructed by the accelerator operator. Calculating means for calculating the engine target rotation speed for each elapsed time; an engine target rotation speed calculated by the calculation means; and an engine target rotation speed on an engine target rotation speed rising curve set by the setting means. Is compared for each elapsed time, and when the calculated engine target rotation speed is higher than the engine target rotation speed on the engine target rotation speed rise curve, the engine target rotation speed at the elapsed time is compared Means for correcting the target engine speed on the rising curve to the speed ratio control means. .

According to the configuration of the first aspect, the engine target rotation speed calculated by the calculation means and the engine target rotation speed on the engine target rotation speed rising curve set by the setting means are set for each elapsed time. When the calculated engine target rotation speed is higher than the engine target rotation speed on the engine target rotation speed increase curve, the engine target rotation speed on the engine target rotation speed increase curve for the elapsed time is compared with Is provided to the speed ratio control means, so that the engine target rotation speed is suppressed to a target value on a predetermined engine target speed rise curve in any rotation speed range, and the target value alone is suppressed from being excessively increased.

As a result, when the accelerator operator such as the accelerator pedal is depressed, the vehicle speed increases according to the driver's intention, and the responsiveness of the vehicle speed to the accelerator operator regardless of the magnitude of the engine speed. And the acceleration is improved without overshoot of the engine speed.

In order to achieve the second object,
According to a second aspect of the present invention, in the same vehicle speed control device, a setting means for setting an engine target rotation speed descent curve indicating an engine target rotation speed that changes in accordance with the elapsed time, and an engine designated by the accelerator operator Calculating means for calculating a target rotation speed for each elapsed time; an engine target rotation speed calculated by the calculation means; and an engine target rotation speed on an engine target rotation speed descent curve set by the setting means. When the calculated engine target rotation speed is smaller than the engine target rotation speed on the engine target rotation speed decrease curve, the engine target rotation speed is reduced during the elapsed time. Means for correcting the target engine speed on the curve to the speed ratio control means.

According to the configuration of the second aspect, the engine target rotation speed calculated by the calculation means and the engine target rotation speed on the engine target rotation speed falling curve set by the setting means are changed for each elapsed time. When the compared and calculated engine target speed is lower than the engine target speed on the engine target speed drop curve,
The engine target rotation speed on the engine target rotation speed drop curve at the elapsed time is given to the speed ratio control means, and the engine target rotation speed in any rotation speed range is set to a target value on a preset engine target speed reduction curve. Thus, it is possible to prevent only the target value from being too low.

As a result, when the accelerator operation member such as the accelerator pedal is returned, the vehicle speed decreases according to the driver's intention.

In order to achieve the third object,
In a third aspect of the present invention, in the configuration of the second aspect, the engine target rotational speed descent curve set by the setting means is set to be substantially equal to the descent speed when the engine is not loaded. I have.

As described above, the engine target rotational speed descent curve set by the setting means is set to be substantially the same as the descent speed when the engine is not loaded. In this range, the engine target rotation speed is suppressed to a value higher than the rotation speed in the coasting state, and the driver can coast the vehicle in line with the driver's desire not to apply the engine brake. Is achieved.

In order to achieve the fourth object,
According to a fourth aspect of the present invention, in the configuration of the second aspect, the engine target rotation speed descent curve set by the setting means is set to be a descent speed lower than the descent speed when the engine is not loaded. . Further, the engine target rotation speed given to the speed ratio control means is increased by an amount corresponding to the speed at which the accelerator operator is operated in the direction of decreasing the engine target rotation speed.

According to this configuration, the engine target rotational speed descent curve set by the setting means is set so as to be lower than the descent speed when the engine is not loaded. In the rotational speed range, the engine target rotational speed is suppressed to a value equal to or higher than the rotational speed when the engine brake is applied, and the vehicle can be decelerated in accordance with the driver's desire to apply the engine brake. . In addition, the engine target rotational speed given to the speed ratio control means is increased by an amount corresponding to the magnitude of the speed at which the accelerator operator is operated in the direction of decreasing the engine target rotational speed. The degree of effectiveness of the engine brake can be changed according to the return speed of the engine.

As described above, when it is desired to apply the engine brake when the accelerator pedal is released, the degree of the effect of the engine brake changes at each return speed of the accelerator pedal.
The effectiveness of the engine brake can be changed according to the operator's intention.

In order to achieve the fifth object,
According to a fifth aspect of the present invention, in the configuration of the second aspect, the engine target rotational speed decreasing curve set by the setting means is set to be a lowering speed than the lowering speed when the engine is not loaded. . Further, the minimum value of the engine target rotation speed on the engine target rotation speed descent curve is set to decrease as the vehicle speed decreases.

According to such a configuration, the engine target rotational speed descent curve set by the setting means is set to be lower than the descent speed when the engine is not loaded. In the rotational speed range, the engine target rotational speed is suppressed to a value equal to or higher than the rotational speed when the engine brake is applied, and the vehicle can be decelerated in accordance with the driver's desire to apply the engine brake. . In addition, the minimum value of the engine target rotation speed on the engine target rotation speed descent curve is set so as to decrease as the vehicle speed decreases. Therefore, when the vehicle speed is high, the engine brake is always applied, and the vehicle speed is reduced. The controllability of the vehicle speed is improved in such a manner that the engine brake becomes ineffective as the vehicle speed decreases.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle speed control device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a vehicle to which the present invention is applied.

As shown in FIG. 1, the vehicle runs with the engine 1 as a drive source, and the driving force of the engine 1 is transmitted through the continuously variable transmission 2 and the differential 3 to the left and right tires 6. 7.

An engine rotation speed sensor 8 for detecting the rotation speed nE of the engine 1 is provided on the output shaft of the engine 1, and a detection signal nE of the sensor 9 is output to the control device 13.

The output shaft of the continuously variable transmission 2 is provided with an output shaft rotation speed sensor 10 for detecting the rotation speed n0 of the output shaft. Is done.

The continuously variable transmission 2 has a speed ratio e (= the ratio of the output shaft rotation speed n0 to the rotation speed nE of the engine 1).
(n0 / nE) is provided with a speed ratio control actuator 9 for shifting the continuously variable transmission 2 so as to become the target speed ratio E.

By operating an accelerator pedal as an accelerator operator provided in the cab of the vehicle,
The engine 1 is driven. Also, the engine brake switch as a selection means provided in the cab is turned on and off.
The engine brake is activated or released by being turned off. The engine brake switch is turned on when the engine brake is to be applied, such as when descending a slope, and is turned off when the engine brake is not required to be performed unnecessarily and a fuel-efficient coasting operation is desired.

The accelerator pedal has an accelerator pedal displacement sensor 11 for detecting a displacement x of the accelerator pedal.
The detection signal x of the sensor 11 is output to the control device 13. The engine brake switch is provided with a state sensor 12 for detecting an on / off state y of the switch. A detection signal y of the sensor 12 is output to the control device 13.

The continuously variable transmission 2 includes a control device 1
3. Controlled by the speed ratio control actuator 9.

That is, the controller 13 is a control signal for setting the speed ratio e to the target speed ratio E by performing an arithmetic process described later based on the sensor output signals nE, n0, x, and y. The actuator command value S is output to the gear ratio control actuator 9.

The speed ratio control actuator 9 is driven according to the input actuator command value S. As a result, the continuously variable transmission 2 is changed to the desired speed ratio E.

The structure of the vehicle to which the present invention is applied is as follows.
FIG. 2 may be a block diagram.

As shown in FIG. 2, this vehicle is driven by a motor 18 driven by a generator 15 driven by the engine 1 as a power source. Differential tires 6 and 7 via differential 3
It is configured to be transmitted to.

The same reference numerals as those in FIG. 1 denote the same components, and a duplicate description thereof will be omitted.
Note that the output shaft rotation speed sensor 10 is disposed on the output shaft of the motor 18 and detects the rotation speed nM of the motor 18.

That is, the control device 13 obtains the target rotation speed NM of the motor output shaft by performing a calculation process described later, and outputs the target rotation speed NM to the inverter control device 20.

Further, in the control device 13, a target rotation speed NE of the engine output shaft is obtained by performing a calculation process described later, and the target rotation speed NE is output to the converter control device 17.

In this way, the inverter 19 is controlled according to the target rotation speed NM output from the control device 13, and the converter 16 is further controlled according to the target rotation speed NE output from the control device 13.

That is, a control signal corresponding to the target rotation speed NM input to the inverter control device 20 is output to the inverter 19, and the inverter 19 changes the drive voltage frequency of the motor 18 according to the control signal, and
Is made to match the rotation speed of the output shaft with the target rotation speed NM.
That is, the inverter control device 20 controls the motor rotation speed n
The inverter frequency and the motor action or the generator action are calculated and output so that the motor rotation speed gradually approaches NM from the deviation between M and the control target motor rotation speed NM.

A control signal corresponding to the target rotational speed NE input to the converter control device 17 is output from the converter 16.
The converter 16 rectifies the power supplied from the generator 15 in response to the control signal,
To control the engine 1 in a driving state and an engine braking state. That is, converter control device 17 detects a DC voltage between converter 16 and inverter 19, and when the DC voltage is equal to or lower than the power generation voltage of generator 15, rectifies the power from generator 15 to generate the DC voltage. When the voltage is equal to or higher than the power generation voltage of the
Is operating, the generator 15 is actuated as a motor from the deviation between the engine rotation speed nE and the target rotation speed NE during engine braking, and the generator rotation speed (= engine rotation speed) gradually becomes the target value NE. The converter 16 acts as an inverter so as to approach, and calculates and outputs the frequency.

The above-mentioned vehicle is assumed to have two left and right drive wheels (for example, a four-wheeled vehicle).
The vehicle to which the present invention is applied may be a one-wheel drive vehicle (for example, a two-wheeled vehicle). Further, the present invention is not limited to a vehicle traveling by wheels, and can be naturally applied to a vehicle traveling by crawler tracks.

The type of the continuously variable transmission 2 is arbitrary.
For example, HST, HMT, and a belt type can be used.

The generator 15 and the motor 18 are assumed to be of the AC type. However, if the converter 15 and the inverter 18 can be combined to perform both the generator function and the motor function, The format is not limited. Also,
In addition to the AC type, a DC type may be used.

Next, the arithmetic processing performed by the control device 13 shown in FIG. 1 will be described with reference to the control block diagram of FIG.

As shown in FIG. 3, first, the sensor rotation speed nE, the output shaft rotation speed n0, the accelerator pedal displacement x, and the on / off state y of the engine brake switch are obtained from the sensors 8, 10, 11, and 12. Each data is sequentially taken into the control device 13 (step 101).

Next, based on a predetermined relationship between the accelerator pedal displacement x and the engine target rotational speed NE (x), an engine target rotational speed NE (x) corresponding to the current accelerator pedal displacement x is obtained. (Step 1
02).

In the next step 103, the engine target rotational speed NE is obtained as follows. here,
As shown in FIG. 5, an engine target rotation speed increase curve L1 indicating the engine target rotation speed NE that changes in accordance with the elapsed time t is set in advance. The target engine speed increase curve L1 is set to be slightly slower than the speed at which the accelerator pedal is depressed when the engine 1 is not loaded.

Each point on the engine target rotation speed increase curve L1 indicates the upper limit of the target rotation speed NE at each elapsed time t.

Therefore, at a certain elapsed time t,
If the target rotational speed NE (x) obtained in step 102 exceeds this upper limit, the upper limit is output to the next step 105 as the engine target rotational speed NE. If the acquired target rotation speed NE (x) is equal to or less than the upper limit,
The target rotational speed NE (x) obtained in step 102 is used as the engine target rotational speed NE as it is in step 10.
5 is output.

This will be described in the case of digital control in which control is performed every cycle Δt. As shown in FIG.
Assuming that the output engine target rotational speed NE is NE1 at an arbitrary time t1, the next one cycle Δ
The upper limit value of the target rotation speed NE at the control time point t2 after t is NE2 from the rising curve L1. Here, at time t2, the target rotational speed NE obtained in step 102 is obtained.
If (x) exceeds the upper limit value NE2, the target rotation speed NE = NE2 is set. If the target rotation speed NE (x) obtained in step 102 is equal to or less than the upper limit value NE2, the target rotation speed NE is set. = NE (x).

In short, the increase speed ((NE NE) of the engine target rotational speed NE (x) instructed by the accelerator pedal
(X) -NE1) / [Delta] t) and a rising speed ((NE2-NE1) / [Delta] t) corresponding to the engine target rotation speed rising curve L1 are compared for each engine target rotation speed NE1, NE2,.
When the instructed increase speed is higher than the increase speed according to the engine target rotation speed increase curve L1, the engine target rotation speed NE is increased along the engine target rotation speed increase curve L1. The target engine speed NE2 on the target engine speed curve L1
Can be output. Therefore, a sensor for directly detecting the increase speed of the engine target rotation speed NE (x) instructed by the accelerator pedal is provided instead of calculating the difference between the rotation speeds, and the sequential output of this sensor and the engine target rotation speed increase curve are provided. You may make it compare with the inclination of the tangent of each point on L1.

Further, when outputting the engine target rotational speed NE to step 105, it is also possible to perform the output after subtracting a predetermined amount ΔNE.

FIG. 7 shows the accelerator pedal depression speed Δx.
6 is a graph showing a relationship between the speed decrease amount ΔNE and the speed decrease amount ΔNE.
As shown in FIG. 7, the speed decrease ΔNE has a relationship that increases as the accelerator depression speed Δx increases. Therefore, as the accelerator pedal depressing speed Δx increases, the engine target rotational speed NE output to step 105 has a relationship of decreasing. As the accelerator pedal depressing speed Δx increases, the effect of decreasing the engine target rotational speed increases. Thus, the effect of suppressing reduction in vehicle speed can be enhanced.

For example, if the engine target rotational speed NE at time t2 in FIG. 5 is the target rotational speed NE2 on the rising curve and the accelerator pedal depression speed Δx is Δx1, the target rotational speed NE2 is reduced to Δx1. The speed obtained by subtracting the corresponding speed decrease ΔNE1 is output to step 105, ie, NE = NE2-ΔNE1.

As described above, the engine target rotational speed is obtained, so that the engine target rotational speed is suppressed to a target value on a predetermined engine target speed increase curve in all rotational speed ranges, and only the target value is obtained. Is suppressed from rising too much. As a result, when the accelerator pedal is depressed, the vehicle speed increases in accordance with the driver's intention, and irrespective of the engine speed, the responsiveness of the vehicle speed to the accelerator pedal is improved, and the engine speed is reduced. There is no overshoot, and the acceleration is improved.

When the engine target rotational speed NE (x) decreases, the engine target rotational speed NE is obtained in the same manner as when the engine target rotational speed NE (x) increases, and is output to step 105.

As shown in FIG. 6, engine target rotation speed decreasing curves L2 and L3 indicating the engine target rotation speed NE that changes in accordance with the elapsed time t are preset. Among them, the descending curve L2 is selected in response to the on-operation of the engine brake switch, and the descending curve L3 is selected in response to the off-operation of the engine brake switch. Here, the descending curve L3 corresponding to the turning off of the engine brake switch is set to be substantially the same as the descending speed when the accelerator pedal is released when the engine 1 is not loaded. Further, the descending curve L2 corresponding to the turning on of the engine brake switch is set so that the descending speed is lower than the descending speed when the accelerator pedal is released when the engine 1 is not loaded.

The minimum value of the engine target rotational speed on the descending curve L2 corresponding to the turning on of the engine brake switch is larger than the minimum value of the engine target rotational speed on the descending curve L3 corresponding to the turning off of the engine brake switch. Is set to a value.

These engine target rotational speed drop curves L
2. Each point on L3 indicates the lower limit of the target rotation speed NE at each elapsed time t.

Therefore, at a certain elapsed time t,
If the target rotation speed NE (x) obtained in step 102 is smaller than this lower limit value, the lower limit value is output as the engine target rotation speed NE to the next step 105, and at a certain elapsed time t, it is obtained in step 102. If the target rotation speed NE (x) is equal to or greater than the lower limit,
The target rotational speed NE (x) obtained in step 102 is used as the engine target rotational speed NE as it is in step 10.
5 is output.

This will be described in the case of digital control in which control is performed at every cycle Δt. As shown in FIG.
After the engine brake switch is turned on (the descending curve L
If the output engine target rotational speed NE is NE3 at an arbitrary time t3 of (2 is selected), the lower limit value of the target rotational speed NE at the control point in time t4 after the next one cycle Δt decreases NE4 is obtained from the curve L2. Here, at time t4, if the target rotation speed NE (x) obtained in step 102 is smaller than the lower limit value NE4, the target rotation speed NE is set to NE4, and step 1 is executed.
If the target rotational speed NE (x) obtained in step 02 is equal to or higher than the lower limit NE4, the target rotational speed NE = NE (x).

In short, the lowering speed ((NE NE) of the engine target rotational speed NE (x) instructed by the accelerator pedal
(X) -NE3) / [Delta] t) and a lowering speed ((NE4-NE3) / [Delta] t) corresponding to the engine target rotational speed lowering curve L2 are compared for each of the engine target rotational speeds NE3, NE4,.
When the instructed descending speed is higher than the descending speed according to the engine target rotational speed descending curve L2, the engine target rotational speed NE is increased along the engine target rotational speed descending curve L2. The target engine speed NE4 on the target engine speed decrease curve L2
Can be output. Therefore, a sensor for directly detecting the decrease speed of the engine target rotational speed NE (x) instructed by the accelerator pedal is provided, instead of taking the difference between the rotational speeds. You may make it compare with the inclination of the tangent of each point on L2.

Further, when outputting the engine target rotational speed NE to step 105, it is also possible to add a predetermined amount ΔNE and then output it.

FIG. 7 is a graph showing the relationship between the accelerator pedal return speed Δx and the speed increase ΔNE. As shown in FIG. 7, the speed increase ΔNE has a relationship that increases as the accelerator return speed Δx increases. Therefore, as the accelerator pedal return speed Δx increases, the engine target rotational speed NE output to step 105 has a relationship of increasing. The greater the accelerator pedal return speed Δx, the greater the effect of increasing the engine target rotational speed. Therefore, the effect of suppressing the increase in the vehicle speed can be enhanced.

For example, the engine target rotational speed NE at time t4 in FIG.
If the accelerator return speed Δx at that time is Δx1, a speed obtained by adding the speed increase ΔNE1 corresponding to Δx1 to the target rotation speed NE4, ie, NE = NE4 + ΔNE1 is output to step 105. Will be.

When the engine brake switch is turned off,
When the descending curve L3 is selected, the same processing as when the descending curve L2 is selected is performed.

By obtaining the engine target rotational speed as described above, the engine target rotational speed in all rotational speed ranges is suppressed to a target value on a predetermined engine target speed decrease curve, and only the target value is reduced. Is suppressed from falling too much.

As a result, when the accelerator pedal is released, the vehicle speed decreases according to the driver's intention.

Further, in particular, when the descending curve L3 is selected, the engine target rotational speed is suppressed to a value higher than the rotational speed in the coasting state in all rotational speed ranges, so that the driver can apply the engine brake. The vehicle can be coasted in line with the desire to not want to, and fuel-efficient traveling is realized.

In particular, when the descending curve L2 is selected and the engine target rotational speed NE is increased by an amount ΔNE corresponding to the magnitude of the accelerator pedal return speed Δx, any rotational speed In this range, the engine target rotation speed is suppressed to a value higher than the rotation speed when the engine brake is applied, and the vehicle can be decelerated in accordance with the driver's desire to apply the engine brake, and Thus, the degree of effectiveness of the engine brake can be changed according to the operator's intention.

Further, the minimum value NE (v) of the engine target rotational speed on the descending curve L2 corresponding to the turning on of the engine brake switch can be changed so as to decrease as the vehicle speed v decreases. FIG. 8 is a graph showing the relationship between the vehicle speed v and the minimum value NE (v).

Therefore, when the descending curve L2 is selected and the minimum value NE (v) is changed in accordance with the vehicle speed v, the engine target rotational speed becomes equal to the engine brake speed in all rotational speed ranges. The engine speed can be reduced to more than the rotation speed when the vehicle is in effect, and the vehicle can be decelerated in accordance with the driver's desire to apply the engine brake. As a result, the controllability of the vehicle speed is improved in such a manner that the engine brake becomes ineffective as the vehicle speed decreases (step 103).

On the other hand, the speed ratio e (= n0 / nE) of the continuously variable transmission 2 is calculated based on the engine speed nE and the output shaft speed n0 obtained in step 101 (step 104).

Further, based on the current engine target rotational speed NE obtained in step 103, the current engine rotational speed nE, and the current speed ratio e obtained in step 104, the target of the continuously variable transmission 2 is determined. The speed ratio E is calculated as follows: E = e + k (nE-NE) (1) Here, k is a constant (step 10).
5).

Next, the current speed ratio e is calculated in step 10
An actuator command value S for obtaining the target speed ratio E obtained in step 5 is calculated (step 106), and the actuator command value S is output to the speed ratio control actuator 9. As a result, the speed ratio e of the continuously variable transmission 2 becomes
The speed is changed according to the actuator command value S, and gradually approaches the target speed ratio E. That is, according to the above equation (1) in step 105, the actual engine speed nE becomes
When the engine rotation speed NE is higher than the engine target rotation speed NE, the speed ratio e is increased in accordance with the difference nE-NE between these two rotation speeds. The speed ratio e is controlled so that the speed ratio e decreases in accordance with the difference nE-NE between the two rotation speeds (step 107).

Next, the arithmetic processing performed by the control device 13 shown in FIG. 2 will be described with reference to the control block diagram of FIG.

The contents of FIG. 4 are obtained by replacing the speed ratio e in FIG. 3 with the rotation speed nM of the motor 18, and replacing the target speed ratio E in FIG. 3 with the target rotation speed NM of the motor 18.

As shown in FIG. 4, first, the respective data of the engine rotation speed nE, the motor rotation speed nM, the accelerator pedal displacement x, and the on / off state y of the engine brake switch are obtained from the sensors 8, 10, 11, and 12. Are sequentially taken into the control device 13 (step 201).

Then, based on a predetermined relationship between the accelerator pedal displacement x and the engine target rotational speed NE (x), an engine target rotational speed NE (x) corresponding to the current accelerator pedal displacement x is obtained. (Step 2
02).

In the next step 203, the engine target rotational speed NE is obtained as follows. here,
As shown in FIG. 5, an engine target rotation speed increase curve L1 indicating the engine target rotation speed NE that changes in accordance with the elapsed time t is set in advance. The target engine speed increase curve L1 is set to be slightly slower than the speed at which the accelerator pedal is depressed when the engine 1 is not loaded.

Each point on the engine target rotation speed increase curve L1 indicates the upper limit of the target rotation speed NE at each elapsed time t.

Therefore, at a certain elapsed time t,
If the target rotation speed NE (x) obtained in step 202 exceeds this upper limit, the next step 204 and 205 is set with the upper limit as the engine target rotation speed NE.
If the target rotation speed NE (x) obtained in step 202 is equal to or less than the upper limit value at a certain elapsed time t, the target rotation speed NE (x) obtained in step 202 is output to the engine target rotation speed NE (x). The speed NE is directly output to steps 204 and 205.

This will be described in the case of digital control in which control is performed every cycle Δt. As shown in FIG.
Assuming that the output engine target rotational speed NE is NE1 at an arbitrary time t1, the next one cycle Δ
The upper limit value of the target rotation speed NE at the control time point t2 after t is NE2 from the rising curve L1. Here, at time t2, the target rotational speed NE obtained in step 202
If (x) exceeds the upper limit NE2, the target rotational speed NE is set to NE2. If the target rotational speed NE (x) obtained in step 202 is equal to or less than the upper limit NE2, the target rotational speed NE is set. = NE (x).

In short, the increase speed ((NE NE) of the engine target rotational speed NE (x) instructed by the accelerator pedal
(X) -NE1) / [Delta] t) and a rising speed ((NE2-NE1) / [Delta] t) corresponding to the engine target rotation speed rising curve L1 are compared for each engine target rotation speed NE1, NE2,.
When the instructed increase speed is higher than the increase speed according to the engine target rotation speed increase curve L1, the engine target rotation speed NE is increased along the engine target rotation speed increase curve L1. The target engine speed NE2 on the target engine speed curve L1
Can be output. Therefore, a sensor for directly detecting the increase speed of the engine target rotation speed NE (x) instructed by the accelerator pedal is provided instead of calculating the difference between the rotation speeds, and the sequential output of this sensor and the engine target rotation speed increase curve are provided. You may make it compare with the inclination of the tangent of each point on L1.

Further, when outputting the engine target rotational speed NE to steps 204 and 205, a predetermined amount ΔΔ
It is also possible to output after subtracting NE.

FIG. 7 shows the accelerator pedal depression speed Δx.
6 is a graph showing a relationship between the speed decrease amount ΔNE and the speed decrease amount NE.
As shown in FIG. 7, the speed decrease ΔNE has a relationship that increases as the accelerator depression speed Δx increases. Therefore, as the accelerator pedal depression speed Δx increases, the engine target rotation speed NE output to steps 204 and 205 has a relationship of decreasing. As the accelerator pedal depression speed Δx increases, the engine target rotation speed decreases. Therefore, the effect of suppressing a decrease in vehicle speed can be enhanced.

For example, assuming that the engine target rotational speed NE at time t2 in FIG. 5 is the target rotational speed NE2 on the rising curve and the accelerator pedal depression speed Δx at that time is Δx1, the target rotational speed NE2 is reduced to Δx1. The speed obtained by subtracting the corresponding speed decrease ΔNE1, NE = NE2-ΔNE1, will be output to steps 204 and 205.

As described above, the engine target rotational speed is obtained, so that the engine target rotational speed is suppressed to a target value on a predetermined engine target speed rise curve in any rotational speed range, and only the target value is obtained. Is suppressed from rising too much. As a result, when the accelerator pedal is depressed, the vehicle speed increases in accordance with the driver's intention, and irrespective of the engine speed, the responsiveness of the vehicle speed to the accelerator pedal is improved, and the engine speed is reduced. There is no overshoot, and the acceleration is improved.

When the engine target rotational speed NE (x) decreases, the engine target rotational speed NE is obtained in the same manner as when the engine target rotational speed NE (x) is increased.
Is output to

As shown in FIG. 6, engine target rotation speed decreasing curves L2 and L3 indicating the engine target rotation speed NE that changes in accordance with the elapsed time t are preset. Among them, the descending curve L2 is selected in response to the on-operation of the engine brake switch, and the descending curve L3 is selected in response to the off-operation of the engine brake switch. Here, the descending curve L3 corresponding to the turning off of the engine brake switch is set to be substantially the same as the descending speed when the accelerator pedal is released when the engine 1 is not loaded. Further, the descending curve L2 corresponding to the turning on of the engine brake switch is set so that the descending speed is lower than the descending speed when the accelerator pedal is released when the engine 1 is not loaded.

The minimum value of the engine target rotational speed on the descending curve L2 corresponding to the turning on of the engine brake switch is larger than the minimum value of the engine target rotational speed on the descending curve L3 corresponding to the turning off of the engine brake switch. Is set to a value.

The engine target rotational speed drop curve L
2. Each point on L3 indicates the lower limit of the target rotation speed NE at each elapsed time t.

Then, at a certain elapsed time t,
If the target rotational speed NE (x) obtained in step 202 is smaller than this lower limit, the lower limit is set as the engine target rotational speed NE and the following steps 204 and 205 are performed.
If the target rotation speed NE (x) obtained in step 202 is equal to or greater than the lower limit value at a certain elapsed time t, the target rotation speed NE (x) obtained in step 202 is output to the engine target rotation speed NE (x). The speed NE is directly output to steps 204 and 205.

This will be described in the case of digital control in which control is performed at intervals of one cycle Δt. As shown in FIG.
After the engine brake switch is turned on (the descending curve L
If the output engine target rotational speed NE is NE3 at an arbitrary time t3 of (2 is selected), the lower limit value of the target rotational speed NE at the control point in time t4 after the next one cycle Δt decreases NE4 is obtained from the curve L2. Here, at time t4, if the target rotation speed NE (x) obtained in step 202 is smaller than the lower limit value NE4, the target rotation speed NE = NE4 is set, and step 2 is executed.
If the target rotational speed NE (x) obtained in step 02 is equal to or higher than the lower limit NE4, the target rotational speed NE = NE (x).

In short, the descending speed ((NE NE) of the engine target rotational speed NE (x) instructed by the accelerator pedal
(X) -NE3) / [Delta] t) and a lowering speed ((NE4-NE3) / [Delta] t) corresponding to the engine target rotational speed lowering curve L2 are compared for each of the engine target rotational speeds NE3, NE4,.
When the instructed descending speed is higher than the descending speed according to the engine target rotational speed descending curve L2, the engine target rotational speed NE is increased along the engine target rotational speed descending curve L2. The target engine speed NE4 on the target engine speed decrease curve L2
Can be output. Therefore, a sensor for directly detecting the decrease speed of the engine target rotational speed NE (x) instructed by the accelerator pedal is provided, instead of taking the difference between the rotational speeds. You may make it compare with the inclination of the tangent of each point on L2.

Further, when outputting the engine target rotational speed NE to steps 204 and 205, a predetermined amount ΔΔ
It is also possible to add only NE and then output.

FIG. 7 is a graph showing the relationship between the accelerator pedal return speed Δx and the speed increase ΔNE. As shown in FIG. 7, the speed increase ΔNE has a relationship that increases as the accelerator return speed Δx increases. Therefore, as the accelerator pedal return speed Δx increases, the engine target rotational speed NE output to steps 204 and 205 has a relation of increasing. The effect that the engine target rotational speed increases as the accelerator pedal return speed Δx increases. Therefore, the effect of suppressing the increase in the vehicle speed can be enhanced.

For example, the engine target rotational speed NE at time t4 in FIG.
Assuming that the accelerator return speed Δx at that time is Δx1, a speed obtained by adding a speed increase ΔNE1 corresponding to Δx1 to the target rotation speed NE4, NE = NE4 + ΔNE1 is obtained for steps 204 and 205. Will be output.

When the engine brake switch is turned off,
When the descending curve L3 is selected, the same processing as when the descending curve L2 is selected is performed.

By obtaining the engine target rotational speed as described above, the engine target rotational speed is suppressed to a value equal to or higher than a target value on a predetermined engine target speed decreasing curve in all rotational speed ranges. Is suppressed from falling too much.

As a result, when the accelerator pedal is released, the vehicle speed decreases according to the driver's intention.

Further, in particular, when the descending curve L3 is selected, the engine target rotational speed is suppressed to a value higher than the rotational speed in the coasting state in all rotational speed ranges, and the driver can apply the engine brake. The vehicle can be coasted in line with the desire to not want to, and fuel-efficient traveling is realized.

In particular, when the descending curve L2 is selected and the engine target rotational speed NE is increased by an amount ΔNE corresponding to the magnitude of the accelerator pedal return speed Δx, any rotational speed In this range, the engine target rotation speed is suppressed to a value higher than the rotation speed when the engine brake is applied, and the vehicle can be decelerated in accordance with the driver's desire to apply the engine brake, and Thus, the degree of effectiveness of the engine brake can be changed according to the operator's intention.

Further, the minimum value NE (v) of the engine target rotational speed on the descending curve L2 corresponding to the turning on of the engine brake switch can be changed so as to decrease as the vehicle speed v decreases. FIG. 8 is a graph showing the relationship between the vehicle speed v and the minimum value NE (v).

Therefore, when the descending curve L2 is selected and its minimum value NE (v) is changed in accordance with the vehicle speed v, the engine target rotational speed becomes equal to the engine brake speed in all rotational speed ranges. The engine speed can be reduced to more than the rotation speed when the vehicle is in effect, and the vehicle can be decelerated in accordance with the driver's desire to apply the engine brake. As the vehicle speed decreases, the controllability of the vehicle speed is improved (step 203).

The engine target rotational speed NE output in this way is output to a converter control device 17, which controls the engine 1 in a driving state and an engine braking state. In this control, the output nE of the engine speed sensor 8 is used as a feedback amount (step 205).

Then, the target engine speed NE obtained in step 203 and the current engine speed n
E, Based on the current motor rotation speed nM, the target rotation speed NM of the motor 18 is calculated as follows: NM = nM + k (nE-NE) (2) Here, k is a constant (step 20).
4).

The motor target rotation speed NM obtained in step 204 is output to the inverter control device 20, and the inverter control device 20 controls the rotation speed of the motor 18 to become the target rotation speed NM. You. That is, when the actual engine rotation speed nE is higher than the engine target rotation speed NE according to the above equation (2) in step 204, the motor rotation speed nM increases according to the difference nE-NE between these two rotation speeds. As described above, when the actual engine rotation speed nE is smaller than the engine target rotation speed NE, the motor rotation speed nM is controlled such that the motor rotation speed nM decreases in accordance with the difference nE-NE between these two rotation speeds. You. In this control, the output n of the motor rotation speed sensor 10 is
M is used as the feedback amount (step 20)
5).

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of an embodiment of a vehicle speed control device according to the present invention.

FIG. 2 is a block diagram illustrating a configuration example of an embodiment of a vehicle speed control device according to the present invention.

FIG. 3 is a control block diagram showing control contents applied to the apparatus of FIG. 1;

FIG. 4 is a control block diagram showing control contents applied to the apparatus of FIG. 1;

FIG. 5 is an engine target rotation speed rise curve diagram used to explain the control contents performed in FIGS. 3 and 4;

FIG. 6 is an engine target rotation speed decrease curve diagram used for explaining the control contents performed in FIGS. 3 and 4;

FIG. 7 is a diagram used to explain the control contents performed in FIGS. 3 and 4, and is a diagram showing a relationship between an operation speed of an accelerator pedal and a decrease or an increase in an engine target rotation speed. It is.

FIG. 8 is a diagram used to explain the control contents performed in FIGS. 3 and 4, and is a graph showing a relationship between a vehicle speed and a minimum value of an engine target rotation speed.

[Explanation of symbols]

 1 engine 13 control device 18 motor

Claims (20)

[Claims] An accelerator operating member for instructing an engine target rotation speed corresponding to an operation position, and a driving force of an engine are transmitted, and a speed ratio of an output shaft rotation speed to an engine rotation speed is determined based on a given control signal. A continuously variable transmission that changes continuously, rotation speed detection means for detecting the actual rotation speed of the engine, and an actual engine speed detected by the rotation speed detection means based on a given engine target rotation speed When the speed is higher than the given engine target speed, the speed ratio is increased in accordance with the deviation between the two speeds, and the detected actual engine speed is set to the given engine target speed. When the rotation speed is lower than the rotation speed, control for changing the speed ratio is performed so that the speed ratio decreases in accordance with the difference between the two rotation speeds. A speed control device for a vehicle, comprising: a speed ratio control unit that outputs a signal; a setting unit that sets an engine target rotation speed increase curve indicating an engine target rotation speed that increases and changes according to elapsed time; Calculating means for calculating the engine target rotation speed indicated by the following for each elapsed time; an engine target rotation speed calculated by the calculation means; and an engine on the engine target rotation speed rise curve set by the setting means. The target rotation speed is compared for each elapsed time, and when the calculated engine target rotation speed is higher than the engine target rotation speed on the engine target rotation speed increase curve, the An engine target rotation speed correction means for giving the engine target rotation speed on the engine target rotation speed rise curve to the speed ratio control means. DOO speed control device for a vehicle equipped with. 2. An engine target rotation speed rising curve set by said setting means is set so as to be a rising speed lower than a rising speed when the engine is not loaded. Vehicle speed control device. 3. The engine target rotation speed given to the speed ratio control means is reduced by an amount corresponding to the speed at which the accelerator operator is operated in a direction to increase the engine target rotation speed. Item 2. The vehicle speed control device according to Item 1. 4. An accelerator operator for instructing an engine target rotation speed corresponding to an operation position, and a driving force of the engine is transmitted, and a speed ratio of an output shaft rotation speed to an engine rotation speed is determined based on a given control signal. A continuously variable transmission that changes continuously, rotation speed detection means for detecting the actual rotation speed of the engine, and an actual engine speed detected by the rotation speed detection means based on a given engine target rotation speed When the speed is higher than the given engine target speed, the speed ratio is increased in accordance with the deviation between the two speeds, and the detected actual engine speed is set to the given engine target speed. When the rotation speed is lower than the rotation speed, control for changing the speed ratio is performed so that the speed ratio decreases in accordance with the difference between the two rotation speeds. A speed ratio control unit that outputs a signal; a speed control device that outputs a signal; a setting unit that sets an engine target rotation speed descent curve indicating an engine target rotation speed that changes in accordance with elapsed time; Calculating means for calculating the engine target rotation speed indicated by the following for each elapsed time; an engine target rotation speed calculated by the calculation means; and an engine on the engine target rotation speed falling curve set by the setting means. The target rotation speed is compared with each elapsed time, and when the calculated engine target rotation speed is smaller than the engine target rotation speed on the engine target rotation speed drop curve, An engine target rotation speed correction means for giving the engine target rotation speed on the engine target rotation speed drop curve to the speed ratio control means. DOO speed control device for a vehicle equipped with. 5. The engine target rotational speed lowering curve set by the setting means is set to be substantially the same as the lowering speed when the engine is not loaded. Vehicle speed control device. 6. The engine target rotational speed lowering curve set by the setting means is set to be a lowering speed than a lowering speed when the engine is not loaded. Vehicle speed control device. 7. A first curve having a substantially same descent speed as a descent speed when the engine is not loaded, as a target engine speed descent curve set by the setting means, 5. The vehicle speed control device according to claim 4, further comprising a selection unit for selecting one of a second curve having a lowering speed than the lowering speed in the case of (1). 8. The vehicle according to claim 7, wherein the minimum value of the engine target rotation speed on the second curve is set to a value larger than the minimum value of the engine target rotation speed on the first curve. Speed control device. 9. The minimum value of the engine target rotational speed on the engine target rotational speed decreasing curve according to claim 6 or the minimum value of the engine target rotational speed on the second curve according to claim 8 is the speed of the vehicle. The vehicle speed control device is set so as to decrease as the vehicle speed decreases. 10. An engine target rotation speed given to said speed ratio control means is increased by an amount corresponding to a magnitude of a speed at which said accelerator operator is operated in a direction to decrease an engine target rotation speed. Item 5. A vehicle speed control device according to item 4. 11. An accelerator operator for instructing an engine target rotation speed corresponding to an operation position, a generator driven by the engine, a motor driven by the power of the generator, and a control signal supplied thereto. A motor control device that changes the speed of the vehicle by changing the rotation speed of the motor, a rotation speed detection unit that detects an actual rotation speed of the engine, and the rotation speed based on a given engine target rotation speed. When the actual engine rotation speed detected by the speed detection means is higher than the given engine target rotation speed, the rotation speed of the motor increases in accordance with the deviation between the two rotation speeds,
Further, when the detected actual engine rotation speed is lower than the given engine target rotation speed, the motor rotation speed is changed so that the rotation speed of the motor decreases in accordance with the difference between these two rotation speeds. Speed control means for outputting a control signal for controlling the speed of the vehicle, comprising: setting means for setting an engine target rotation speed increase curve indicating an engine target rotation speed that increases and changes according to elapsed time; Calculating means for calculating an engine target rotation speed designated by an operator for each elapsed time; an engine target rotation speed calculated by the calculation means; and an engine target rotation speed rising curve set by the setting means. The engine target rotational speed is compared with the engine target rotational speed for each elapsed time, and the calculated engine target rotational speed is compared with the engine target rotational speed. When the engine target rotation speed is higher than the engine target rotation speed on the speed increase curve, the engine target rotation speed on the engine target rotation speed increase curve at the elapsed time is given to the speed control unit by engine target rotation speed correction means. A vehicle speed control device comprising: 12. The engine target rotation speed rise curve set by the setting means is set to be a rise speed lower than the rise speed when the engine is not loaded. Vehicle speed control device. 13. The engine target rotation speed given to the speed control means is reduced by an amount corresponding to the speed at which the accelerator operator is operated in a direction to increase the engine target rotation speed. 12. The vehicle speed control device according to claim 11. 14. An accelerator operator for instructing an engine target rotation speed corresponding to an operation position, a generator driven by the engine, a motor driven by the power of the generator, and a control signal supplied thereto. A motor control device that changes the speed of the vehicle by changing the rotation speed of the motor, a rotation speed detection unit that detects an actual rotation speed of the engine, and the rotation speed based on a given engine target rotation speed. When the actual engine rotation speed detected by the speed detection means is higher than the given engine target rotation speed, the rotation speed of the motor increases in accordance with the deviation between the two rotation speeds,
Further, when the detected actual engine rotation speed is lower than the given engine target rotation speed, the motor rotation speed is changed so that the rotation speed of the motor decreases in accordance with the difference between these two rotation speeds. A speed control device for outputting a control signal for the vehicle, comprising: a setting device for setting an engine target rotation speed descent curve indicating an engine target rotation speed that changes in accordance with the elapsed time; Calculating means for calculating an engine target rotation speed designated by an operator for each elapsed time; an engine target rotation speed calculated by the calculation means; and an engine target rotation speed falling curve set by the setting means. The engine target rotational speed is compared with the engine target rotational speed for each elapsed time, and the calculated engine target rotational speed is compared with the engine target rotational speed. When the engine target rotational speed on the speed decrease curve is smaller than the engine target rotational speed, the engine target rotational speed on the engine target rotational speed decrease curve at the elapsed time is provided to the speed control unit. A vehicle speed control device comprising: 15. The engine target rotational speed decreasing curve set by the setting means is set to be substantially the same as the descending speed when the engine is not loaded. Vehicle speed control device. 16. The engine target rotational speed lowering curve set by the setting means is set to be a lowering speed than a lowering speed when the engine is not loaded. Vehicle speed control device. 17. A first curve, which is substantially equal to a lowering speed when the engine is not loaded, as the engine target rotational speed lowering curve set by the setting means; 15. The vehicle speed control device according to claim 14, further comprising a selection unit for selecting one of a second curve having a lowering speed than the lowering speed in the case of (1). 18. The vehicle according to claim 17, wherein the minimum value of the engine target rotation speed on the second curve is set to a value larger than the minimum value of the engine target rotation speed on the first curve. Speed control device. 19. The minimum value of the engine target rotation speed on the engine target rotation speed decreasing curve according to claim 16 or the minimum value of the engine target rotation speed on the second curve according to claim 18 is the speed of the vehicle. The vehicle speed control device is set so as to decrease as the vehicle speed decreases. 20. The engine target rotation speed given to the speed control means is increased by an amount corresponding to the speed at which the accelerator operator is operated in the direction of decreasing the engine target rotation speed. 15. The vehicle speed control device according to claim 14.