JP3405185B2 - Driving force control device for vehicle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle equipped with a continuously variable transmission, and more particularly to a control device for controlling deceleration by engine braking or the like during downhill driving.

[0002]

2. Description of the Related Art An engine capable of controlling torque independently of accelerator operation by a driver and a continuously variable transmission (CVT: Con) capable of continuously controlling a gear ratio.
tinous Variable Transmis
There is a concept of "driving force control" that realizes a positive and negative target driving torque calculated based on an accelerator operation amount, a driving condition, and the like with a predetermined engine torque and a CVT gear ratio in a vehicle equipped with an engine operating condition. By using this driving force control, it is possible to easily change the dynamic characteristics of the vehicle by the method of producing the target driving torque, and use the point where the engine fuel consumption rate is the smallest when calculating the engine torque and the CVT gear ratio. If the logic is configured as described above, there is an advantage that a desired target driving force can be realized with optimal fuel consumption. Here, in general, the engine and the CVT are often controlled by separate controllers, and it is necessary to send and receive data between the controllers by communication in order to realize the driving force control.

When the accelerator opening is equal to or less than a predetermined value near the fully closed position, a predetermined negative target drive torque is set according to the accelerator opening so as to realize the negative target drive torque. In addition, there is known a technique for controlling an engine torque and a gear ratio of a vehicle to realize engine braking according to a driver's intention (see Japanese Patent Laid-Open No. 62-199536).

[0004]

However, in a state where the data transmission and reception between the controllers cannot be normally performed (fail state), the driving force control based on the target driving torque cannot be performed, so that the engine and the CVT are separately provided. Need to control. Here, when the conventional engine drive control based on the target drive torque is applied to the system for performing the drive force control, when the control based on the target drive torque request can be performed, the engine drive control is normally executed using the negative target drive torque. However, when the control based on the target drive torque request cannot be performed due to the failure, the engine and the CVT are individually controlled, and therefore the engine shake control based on the target drive torque cannot be executed. Therefore, when such a failure occurs, it is not possible to control the appropriate embrace force according to the slope even if it goes downhill, and if a failure occurs during the embrace control, it is performed until then. In addition, there is a possibility that a driving force level difference may occur due to the elimination of the correction control of the embracing force, and as a result, the driver feels uncomfortable.

For this reason, according to the present invention, when the accelerator opening is fully closed or at a predetermined opening near the fully closed position or less, the gear ratio correction amount for realizing the target deceleration of the vehicle is first set. Calculated, and then the gear ratio correction amount and the operating state of the vehicle at that time (engine speed, presence or absence of fuel cut, etc.)
From the above, it is calculated in advance how much the drive torque changes when the above gear ratio is corrected, and this is used as the correction amount of the target drive torque. With this, when control based on the target drive torque request can be performed, engine braking is realized by the calculated correction amount of the target drive torque, and when control based on the target drive torque request cannot be performed due to a failure, the calculation is performed first. The object of the present invention is to solve the above-mentioned problems by realizing engine braking using the gear ratio correction amount.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 is an engine capable of controlling torque independently of the accelerator operation of a driver,
A continuously variable transmission capable of continuously controlling the gear ratio, and a driving force control capable of realizing a positive and negative target drive torque calculated based on operating conditions and the like with a predetermined engine torque and a gear ratio. A vehicle equipped with a system, a deceleration detecting means for detecting a deceleration of the vehicle, and a target input rotation for calculating a correction amount of a target input rotation speed of the continuously variable transmission based on an output of the deceleration detecting means. Number correction amount calculation means, target drive torque correction amount calculation means for calculating the correction amount of the target drive torque based on the output of the target input rotation speed correction amount calculation means, and driver operation detection means for detecting the operation of the driver. A target drive torque calculation means for calculating a target drive torque based on the output of the driver operation detection means, an output of the target drive torque calculation means, and a target drive torque correction amount calculation means Target drive torque correction means for correcting the target drive torque based on the output, and drive torque distribution calculation for calculating the distribution of the gear ratio and engine torque for realizing the drive torque based on the output of the target drive torque correction means. Means, a driving force control execution determining means for determining whether or not the driving force control can be performed, an output of the driving force control execution determining means, an output of the target input speed correction amount calculating means, and the driving torque. Based on the gear ratio control means for controlling the gear ratio based on the output of the distribution calculating means, the output of the driving force control execution judging means, the output of the driving torque distribution calculating means, and the output of the driver operation detecting means. In a vehicle having an engine torque control means for controlling the engine torque, the drive force control execution determination means determines that the drive force control based on the target drive torque can be executed. In this case, the gear ratio control means performs gear ratio control based on the output of the drive torque distribution calculation means, and the engine torque control means performs engine torque control based on the output of the drive torque distribution calculation means. When the drive force control execution determination means determines that the drive force control based on the target drive torque cannot be performed, the gear ratio control means determines the target input rotation speed calculated in the gear ratio control means and the The gear ratio control is performed based on the output of the target input rotation speed correction amount calculation means, and the engine torque control means controls the engine torque based on the output of the driver operation detection means.

The invention described in claim 2 is the same as claim 1
In the vehicle driving force control device described in (1), the target drive torque correction amount calculation means has previously checked the output of the target input speed correction amount calculation means and the vehicle speed or the output side rotation speed of the continuously variable transmission. It is characterized in that it is means for calculating a correction amount of the target drive torque based on the engine characteristics and the specifications of the vehicle.

The invention described in claim 3 is the same as claim 1
Alternatively, in the vehicle driving force control device according to the second aspect, when the driving force control execution determination means determines that data transmission / reception cannot normally be performed between the gear ratio control and engine torque control control devices, the target It is characterized in that it is means for judging that the driving force control based on the driving torque cannot be executed.

Further, in the invention described in claim 4, in the vehicle driving force control device according to any one of claims 1 to 3, the drive torque distribution calculation means is output from the target drive torque correction means. When the target drive torque is positive, the target input rotational speed of the transmission and the target engine torque are calculated so that the energy consumption of the engine is minimized when the target drive torque is positive. In this case, it is a means for calculating a target input rotation speed of the transmission and a negative engine torque for realizing the target driving torque.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a vehicle driving force control device according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing a basic configuration of a vehicle driving force control device according to the present invention.

First, the configuration will be described with reference to FIG.
Reference numeral 01 is a deceleration detection means for detecting the deceleration of the vehicle, and 102 is a target input rotation speed correction amount calculation means for calculating the correction amount of the target input rotation speed of the CVT based on the output of the deceleration detection means 101. Reference numeral 103 is a target drive torque correction amount calculation means for calculating the correction amount of the target drive torque based on the output of the target input rotation speed correction amount calculation means 102. Reference numeral 104 is a driver operation detecting means for detecting an operation of the driver, and 105 is a driver operation detecting means 10.
4 is a target drive torque calculation means for calculating a target drive torque based on the output of No. 4. Reference numeral 106 denotes a target drive torque correction amount calculation means 103 and a target drive torque calculation means 105.
Is a target drive torque correction means for correcting the target drive torque based on the output of the target drive torque. is there. 108
Reference numeral 109 is a driving force control execution determining means for determining whether control based on the target driving torque can be performed. 110 is a gear ratio control means for controlling the gear ratio based on the output of 108.
Is an engine torque control means for controlling the engine torque based on the outputs of the driver operation detection means 104, the driving torque distribution calculation means 107, and the driving force control execution determination means 108.

FIG. 2 is a drive system configuration diagram of a vehicle to which an embodiment of the present invention is applied. Explaining the configuration, the engine 1 is equipped with an electronically controlled throttle 2 for controlling the intake air amount, an air filter 3 and an exhaust catalyst 4 for cleaning exhaust gas, and the like. A torque converter 5 for increasing the torque is connected. The torque converter 5 is connected with a CVT 6 capable of continuously controlling the gear ratio, and the CVT 6 is connected with a final gear 7. And final gear 7
Brake 8 and drive wheel 9 are connected to the output shaft of
The driving force is transmitted to the road surface.

Input / output of information to / from the outside and various operations are realized by a circuit centered on the microcomputer shown in FIG. The CPU 301 executes the calculation and RO
The M302 stores in advance control programs, various data, and the like, which will be described later. The RAM 303 temporarily stores information during program execution. Input port 304
Inputs information from an external sensor or the like, and the A / D converter 305 performs A / D conversion for handling an analog signal from the outside by a computer. The output port 306 outputs a signal for driving an external device.

A vehicle equipped with an electronically controlled throttle or the like that can control the engine torque independently of driver operation, and a transmission that can continuously control the gear ratio (or input rotation) like the CVT. In the above, there is an idea of "driving force control" in which a target drive torque is calculated based on the driver's accelerator operation amount and the vehicle body speed, and the engine torque and the gear ratio are controlled so as to realize the target drive torque. In this method, the dynamic characteristics of the vehicle can be easily changed by the method of making the target drive torque, and the logic is used to calculate the engine torque and the CVT gear ratio so that the point where the fuel consumption rate of the engine is the smallest is used. If configured, there is an advantage that a desired target driving force can be realized with optimum fuel consumption. In such a vehicle, the engine and the CVT are generally controlled by separate controllers, and it is necessary to send and receive data between the controllers in order to realize driving force control. A state in which sending and receiving of messages cannot be performed normally (failed state)
In this case, since the driving force control based on the target driving torque cannot be performed, it is necessary to "individually control" the engine and the CVT as in the conventional vehicle.

Now, consider the case where the engine brake is controlled on a downhill in such a vehicle. While the "driving force control" is being performed, the conventional technique (Japanese Patent Laid-Open No. 62-1 / 1987)
FIG. 4 shows a case where the engine shake control is performed by correcting the target drive torque as in Japanese Patent Publication No. 99536). In this case, if the state of "driving force control" is changed to "non-driving force control (individual control)" for the reasons described above while the engine shake control is being performed, as shown in FIG. Since the calculated correction amount of the target drive torque is no longer reflected in the target input rotation speed, the drive torque does not always change continuously before and after that, and a torque step may occur.

Therefore, when the "non-driving force control (individual control)" is performed, the target input rotational speed correction amount is constantly calculated so that the engine shake control by the correction of the target input rotational speed can be realized. In this state, if the target drive torque correction amount is calculated based on the target input rotation speed correction amount and the engine control is realized using this, the "driving force control" will be changed from "drive force control" during the engine control as in the above example. Even if the mode is switched to the non-driving force control (individual control), the engine braking can be continued smoothly. Also, even if the "driving force control" is switched to "non-driving force control (individual control)" while the engine is not being controlled, the driver will feel uncomfortable because similar engine characteristics are obtained before and after that. Can be prevented.

It is now assumed that the input rotation speed correction amount ΔtNin of the CVT for obtaining the desired deceleration is calculated. Also,
Considering the case where the torque converter is locked up (L / U), engine speed Ne = CVT input speed N
Since the delay of CVT is small, the input rotation speed Ni
It can be regarded that n≈target input speed tNin.

Here, the relationship between the engine speed and the engine torque can be experimentally investigated in advance as the relationship shown in FIG. 6, and the engine speed Ne0 and the engine torque Te0 (here, when the fuel is cut off) When the CVT input speed is corrected by ΔtNin under the condition of (1), the engine torque changes by ΔTe and Te1
It turns out that

Now, engine torque Te0, CVT input rotation Nin0 (= Ne0), CVT output rotation Nout,
Given the final gear ratio Gf, the driving torque Td0 at that time can be obtained as follows.

[0020]

[Equation 1]

Now, the input rotation speed is changed from Nin0 to Nin0.
If corrected to + ΔtNin, the engine torque becomes Te1 from the relationship of FIG. 6, so the vehicle speed is constant (Nout
If it is regarded as 0 constant), the driving torque Td1 at that time can be calculated as follows.

[0022]

[Equation 2]

That is, the input rotation speed of the CVT is ΔtNin
The change in the drive torque when only the correction is performed is represented by the second and third terms on the right side of the equation (2). Therefore, FIG.
The engine characteristics such as those shown in are investigated beforehand, and the CVT input rotation Nin0 (= Ne0) and CVT at that time are
From the output rotation Nout and the final gear ratio Gf, the second and third terms on the right side of the equation (2) are calculated to obtain the target drive torque correction amount ΔtTd, which is used to correct the target drive torque. It is possible to realize a correction substantially equivalent to the correction ΔtNin.

Using this method, as shown in FIG.
While "driving force control" is being performed, the engine drive control is performed using the calculated target drive torque correction amount ΔtTd, and when "non-driving force control (individual control)" is being performed, the engine drive control is performed using ΔtNin. By doing so, even if the "driving force control" and the "non-driving force control (individual control)" are switched during the engine control, the engine control can be smoothly continued. Also, even if the "driving force control" is switched to "non-driving force control (individual control)" while the engine is not being controlled, the driver will feel uncomfortable because similar engine characteristics are obtained before and after that. Can be prevented.

Up to this point, the case where the fuel is cut has been described. However, as shown in FIG. 6, the engine torque characteristic changes depending on whether the fuel is cut or the fuel is not cut. Each has its own data, and the data to be used will be selected according to the state of the engine (whether fuel is cut or not) at that time.

Further, regarding the calculation of ΔtTd, the equation (2)
Although it has been described that the second and third terms on the right side are used, ΔtTd may be calculated using only the second term on the right side of Expression (2) because the third term on the right side is minute.

The operation of this embodiment will be described with reference to FIG. The procedure of FIG. 11 is executed every 10 [ms],
In step S1101 in the figure, the acceleration α of the vehicle body is detected, and in step S1102, the correction amount ΔtNin of the target input rotation speed of the CVT is calculated based on the detected acceleration α.

In step S1103, the engine speed N
e, the CVT output speed Nout, the vehicle speed VSP, and the accelerator operation amount APS are detected, and it is determined in step S1104 whether the driving force control can be executed. Here, whether or not the driving force control can be executed is determined by another routine (not shown), and the determination is executed based on the flag or the like in step S1104.

When it is determined in step S1104 that the driving force control cannot be executed, the process proceeds to step S1105, and the target input rotation speed map (see FIG. 7) is used when the engine and the CVT are individually controlled. tNin0
Is calculated.

In step S1106, step S11
The final target input speed tNin is calculated from the target input speed correction amount ΔtNin calculated in 02 and the target input speed tNin0 calculated in step S1105. In step S1107, the engine and the CVT are individually controlled. The target engine torque tTe is calculated from the target engine torque map (see FIG. 8), and the process ends.

When it is determined in step S1104 that the driving force control can be executed, the process proceeds to step S1108, the target driving torque tTd0 is calculated from the target driving force torque map (see FIG. 9), and the fuel cut is performed in step S1109. To determine if Here, whether or not the fuel cut is to be performed is determined by an engine torque control logic (not shown), and step S1109
Then, it is assumed that the judgment is executed based on the flag or the like.

If it is determined in step S1109 that the fuel is being cut, the process proceeds to step S1110, and the target drive torque is calculated based on the above equation (2) using the data of "with F / C" in the engine characteristics of FIG. When the correction amount ΔtTd is calculated, and it is determined in step S1109 that the fuel cut is not being performed, the process proceeds to step S1111 and the above equation (2) is used using the data of “F / C not included” in the engine characteristics of FIG. The target drive torque correction amount ΔtTd is calculated based on

Step S1110 or step S1
After the target drive torque correction amount ΔtTd is calculated in 111, the process proceeds to step S1112, and the final target drive torque is calculated by the target drive torque tTd0 calculated in step S1108 and the target drive torque correction amount ΔtTd calculated in step S1110 or step S1111. Calculate tTd.

Next, in step S1113, the target input speed tNin is calculated from the target input speed map (see FIG. 10) during driving force control, and in step S1114,
The target engine torque tTe is calculated from the target drive torque tTd calculated in step S1112, the actual gear ratio G, the final gear ratio Gf, and the engine torque correction amount ΔtTe calculated in a routine (not shown), and the process ends. Here, the engine torque correction amount ΔtTe is for correcting the amount by which the drive torque decreases in proportion to the time change rate of the gear ratio and the time change rate of the vehicle speed (inertia torque).

Although not shown here, FIG.
CVT in another routine based on the target input speed tNin and the target engine torque tTe calculated in the routine
Shift control and engine torque control are executed.

Although the embodiment in which a gasoline engine is used as the "engine" in the claims is shown here, the "engine" can also achieve the same effect with a diesel engine or a motor. .

[0037]

As described above in detail, the first aspect of the present invention is as follows.
According to the invention, the deceleration of the vehicle is detected and the gear ratio and the engine torque are controlled, so that the optimum deceleration characteristic can be obtained according to the driving condition, and the driving force control based on the target driving torque is performed. If possible, perform gear ratio control and engine torque control based on the output of the drive torque distribution calculation means,
When the driving force control cannot be performed, the gear ratio control is performed based on the target input speed calculated in the gear ratio control means and the output of the target input speed correction amount calculation means, and based on the output of the driver operation detection means. When the engine torque is controlled by the control of the engine torque to switch from the state in which the driving force can be controlled to the state in which the driving force cannot be controlled due to a communication failure or the like,
It is possible to prevent the driver from feeling uncomfortable because the behavior of the engine control changes before and after that.

According to the second aspect of the present invention, the target drive torque correction amount corresponding to the target input rotational speed correction amount can be calculated with high accuracy, and thus the driving force control can be performed or not. However, the same deceleration characteristic can be obtained.

Further, according to the third aspect of the present invention, the drive force control based on the target drive torque cannot be executed when the transmission / reception of data between the control devices for the gear ratio control and the engine torque control cannot be performed normally. Even if the driving force control cannot be performed, it is possible to obtain the same deceleration characteristic as in the case where the driving force control cannot be performed.

Further, according to the invention of claim 4, when the target drive torque output from the target drive torque correction means is realized, and the target drive torque is positive, the energy consumption of the engine is minimized. In this way, the target input speed of the transmission and the target engine torque are calculated, and when the target drive torque is negative, the target input speed of the transmission and the negative engine torque to achieve the target drive torque are calculated. It is possible to obtain optimum deceleration characteristics while minimizing the energy consumption of the engine.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of a vehicle driving force control device according to the present invention.

FIG. 2 is a drive system configuration diagram of a vehicle to which an embodiment of the present invention is applied.

FIG. 3 is a configuration diagram of an electric circuit that inputs / outputs information to / from the outside and executes various calculations.

FIG. 4 is a diagram for explaining a problem in the conventional technique.

FIG. 5 is a diagram showing an effect of the present invention.

FIG. 6 is a diagram showing characteristics of an engine.

FIG. 7 is a diagram showing an example of a target input rotation speed map when the engine and the CVT are individually controlled.

FIG. 8 is a diagram showing an example of a target engine torque map when the engine and the CVT are individually controlled.

FIG. 9 is a diagram showing an example of a target drive torque map when drive force control is performed.

FIG. 10 is a diagram showing an example of a target input rotation speed map when driving force control is performed.

FIG. 11 is a flowchart showing a specific procedure according to the embodiment of the present invention.

[Explanation of symbols]

101 deceleration detection means 102 target input speed correction amount calculation means 103 target drive torque correction amount calculation means 104 driver operation detecting means 105 Target drive torque calculation means 106 target drive torque correction means 107 Drive torque distribution calculation means 108 driving force control execution determination means 109 gear ratio control means 110 Engine torque control means

Continuation of front page (51) Int.Cl. ⁷ Identification code FI F16H 9/00 F16H 9/00 F 61/12 61/12 // F16H 59:18 59:18 59:48 59:48 (56) References JP 9-112680 (JP, A) JP 60-98254 (JP, A) JP 4-50551 (JP, A) JP 62-110536 (JP, A) JP 9-202158 (JP, A) JP-A-6-201003 (JP, A) JP-A-5-118347 (JP, A) JP-A-3-144163 (JP, A) JP-A-59-187153 (JP, A) Kaihei 11-51172 (JP, A) JP 8-318765 (JP, A) JP 10-299885 (JP, A) JP 5-168110 (JP, A) JP 11-78621 ( (58) Fields investigated (Int.Cl. ⁷ , DB name) B60K 41/14 B61K 41/00 301 F02D 29/00 F16H 9/00 F16H 61/12

Claims (4)

(57) [Claims] 1. An engine capable of controlling torque independently of accelerator operation by a driver, and a continuously variable transmission capable of continuously controlling a gear ratio, and calculated based on operating conditions and the like. A deceleration detecting means for detecting a deceleration of the vehicle, the deceleration detecting means for detecting a deceleration of the vehicle, the vehicle comprising a driving force control system capable of realizing the positive and negative target drive torques with a predetermined engine torque and a gear ratio. Target input speed correction amount calculation means for calculating the correction amount of the target input speed of the continuously variable transmission based on the output of the means, and correction of the target drive torque based on the output of the target input speed correction amount calculation means. Target drive torque correction amount calculation means for calculating the amount, driver operation detection means for detecting the driver's operation, and target drive for calculating the target drive torque based on the output of the driver operation detection means. And a target drive torque correction means for correcting the target drive torque based on the output of the target drive torque calculation means and the output of the target drive torque correction amount calculation means, and the output of the target drive torque correction means. Drive torque distribution calculating means for calculating a gear ratio and engine torque distribution for realizing the drive torque based on the above, drive force control execution determining means for determining whether or not the drive force control is possible, and the drive force A gear ratio control means for controlling a gear ratio based on the output of the control execution determination means, the output of the target input speed correction amount calculation means, and the output of the drive torque distribution calculation means, and the drive force control execution determination means. Output, the output of the drive torque distribution calculation means, and the engine torque control means for controlling the engine torque based on the output of the driver operation detection means. In the vehicle, when the drive force control execution determination means determines that the drive force control based on the target drive torque can be executed, the gear ratio control means performs the gear ratio control based on the output of the drive torque distribution calculation means. The engine torque control means performs engine torque control based on the output of the drive torque distribution calculation means, and the drive force control execution determination means determines that drive force control based on the target drive torque cannot be performed. In this case, the gear ratio control means performs gear ratio control based on the target input speed calculated in the gear ratio control means and the output of the target input speed correction amount calculation means, and the engine torque control means Is a drive force control device for a vehicle, wherein the engine torque is controlled based on the output of the driver operation detection means. 2. The vehicle drive force control device according to claim 1, wherein the target drive torque correction amount calculation means outputs the output of the target input rotation speed correction amount calculation means and the output side of the vehicle speed or the continuously variable transmission. A vehicle driving force control device, which is a means for calculating a correction amount of a target driving torque based on a rotational speed, an engine characteristic that has been checked in advance, and a specification value of the vehicle. 3. The vehicle driving force control device according to claim 1, wherein the driving force control execution determining means can normally transmit and receive data between the gear ratio control and engine torque control control devices. A driving force control device for a vehicle, which is means for determining that the driving force control based on the target driving torque cannot be executed when it is determined that the driving force control is not possible. 4. The vehicle drive force control device according to claim 1, wherein the drive torque distribution calculation means realizes the target drive torque output from the target drive torque correction means. , When the target drive torque is positive, the target input speed of the transmission and the target engine torque are calculated so that the energy consumption of the engine is minimized, and when the target drive torque is negative, the target drive torque is realized. Is a means for calculating a target input rotation speed of the transmission and a negative engine torque for the vehicle.