JPS61171618A - Speed control device for engine vehicle equipped with stepless transmission - Google Patents

Abstract

PURPOSE:To enable a constant speed running to be accomplished by configurating a device in such a manner that a required quantity of fuel and a required change gear ratio are determined based on both an engine necessary horse power which is computed on the basis of a deviation of an actual speed, and the actual speed so as to control a fuel feed device and the transmission. CONSTITUTION:An actual speed NW from a speed sensor 5, and a target speed NWC from a target speed command device 6 are inputted into No.1 arithmetic circuit 8 of a control device 7. An engine necessary horse power is computed based on the computed difference between the actual speed NW and the target speed NWO and then is inputted into No.2 arithmetic circuit 9 computes the obtained data together with the actual speed NW and determines a required change gear ratio (e) and a required quantity of fuel Q, signals for which are then outputted to the stepless transmission 3 and a fuel feed device 2 respective ly in controlling both the engine 1 and the transmission 3 so as to maintain a constant speed. This configuration enables a constant speed running to be accomplished.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides an engine vehicle equipped with a transmission (hereinafter referred to as a continuously variable transmission) capable of continuously changing the gear ratio without any steps. The present invention relates to a device that controls traveling speed by controlling fuel supply amount and gear ratio.

(Prior Art) Conventionally, as a control device for controlling the engine (fuel injection amount) and gear ratio of an engine vehicle equipped with a continuously variable transmission,
There is one described in Japanese Patent Application Laid-Open No. 58-398.70. This device uses the amount of depression of the accelerator pedal as a value that indicates what percentage of the engine's maximum output the driver wants to drive.
Based on the amount of depression of the accelerator pedal, the engine target rotation speed and fuel supply amount are determined based on a predetermined functional relationship (for example, the relationship with the lowest fuel consumption), and the deviation between the engine target rotation speed and the actual rotation speed is determined. This is to control the gear ratio of the continuously variable transmission in the direction of decreasing the gear ratio.

(Problems to be Solved by the Invention) On the other hand, today even in engine vehicles equipped with continuously variable transmissions, constant speed driving control, which is widely practiced in conventional engine vehicles equipped with multi-stage transmissions, cannot be applied. desired. However, when trying to perform constant speed driving control using the above conventional example, the above conventional example focuses on the engine speed and controls the engine and continuously variable transmission so that the engine speed becomes the target speed. Therefore, although it is possible to keep the engine speed constant, it is not possible to keep the vehicle running speed constant when the load on the vehicle changes due to driving conditions. It was impossible to control it.

Accordingly, the present invention provides a speed control device that enables constant speed running in an engine vehicle equipped with a continuously variable transmission.

(Means for Solving the Problems) In order to solve the above problems, the present invention commands a target traveling speed as a target vehicle speed signal by a target vehicle speed command device, and measures the actual traveling speed by a vehicle speed sensor of the actual vehicle. A first arithmetic circuit calculates the required horsepower as an engine required horsepower signal from the target vehicle speed signal and the actual vehicle speed signal based on the deviation between both signals, and calculates the required horsepower as an engine required horsepower signal from the target vehicle speed signal and the actual vehicle speed signal. A second arithmetic circuit calculates the fuel supply amount and gear ratio as electrical signals, respectively, and controls the fuel supply device and the continuously variable transmission, respectively, thereby enabling constant speed running.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In Fig. 1, 1 is an engine, 2 is a combustion engine instructed by an external electric signal ([eJIQi=”°1”′
With the fuel supply system ``'°''''''l[&t;i, the engine 1 outputs an engine torque TE that is a function of the fuel q supplied from the fuel supply system 2. 3 is engine 1
A continuously variable transmission mechanically connected to the engine 1 transmits the engine 1~LUQ TE from the engine 1. The continuously variable transmission 3 has an axle 4 mechanically connected to its output shaft, and converts the engine torque TE into an axle torque TV according to the gear ratio e instructed as an electric signal from the outside, and transmits it to the 1f axle 4. . 5 is mechanically connected to the output shaft of the continuously variable transmission 3 and represents the actual running speed of the vehicle.

That is, the speed sensor detects the actual vehicle speed NW and outputs the detection result as an electrical signal. 6 is a target vehicle speed command device that commands the target running speed of the vehicle, that is, the target vehicle speed NWO, which uses a sensor that detects the amount of depression of the accelerator pedal and the throttle opening, and an adjustment lever to set the vehicle speed when driving at a constant speed. It may be any device that commands the vehicle speed using an electrical signal, such as a vehicle speed setting device or an electronic device that commands the vehicle speed. Reference numeral 7 calculates the fuel supply amount Q and gear ratio e by inputting electrical signals indicating the actual vehicle speed NW and target vehicle speed NWO from the vehicle speed sensor 5 and the target vehicle speed command device 6, respectively, and calculates the fuel supply amount Q and the gear ratio e using each calculation result as an electrical signal. This is a control device that issues commands to the supply device 2 and the continuously variable transmission 3, and is composed of a microcomputer and the like.

This control device 7 includes first and second arithmetic circuits 8 and 9.
The first arithmetic circuit 8 compares the actual vehicle speed NW and the target vehicle speed NWO output as electrical signals from the vehicle speed sensor 5 and the target vehicle speed command device 6, respectively, and determines the engine demand which is a function of the deviation between the two. The second arithmetic circuit 9 calculates the horsepower P, and the second arithmetic circuit 9 calculates the actual vehicle speed NW and engine required horsepower P output from the vehicle speed sensor 5 and the first arithmetic circuit 8, respectively.
Based on this, the fuel supply amount Q and the gear ratio e are calculated and output as electric signals to the fuel supply device 2 and the continuously variable transmission 3, respectively.

Next, the operation of this embodiment will be explained using the flowchart shown in FIG. FIG. 2 is a diagram showing a control routine in the control device 7. When the operation is started in step 10,
After proceeding to step 11 and performing necessary initialization, proceeding to step 12, it is determined whether or not the vehicle is in a constant speed running state. Here, whether or not the vehicle is in a constant speed driving state can be determined from the presence or absence of an output from the target vehicle speed command device 16, etc.

If it is determined in step 12 that the vehicle is not in a constant speed running state, step 12 is repeated and the process waits at step 12 until the constant speed running state is reached, and when it is determined that the constant speed state is present, the process proceeds to step 13.

In step 13, the target vehicle speed N from the target vehicle speed command device 6 is
W○ is taken in, and then in step 14, the actual vehicle speed NW detected by the vehicle speed sensor 5 is taken in, and in step 15, the deviation (NWO-NW) between the target vehicle speed NWO and the actual vehicle speed Nv is calculated, and the steps are performed based on this deviation. In step 16, the engine required horsepower P is calculated. This step 13 to step 1
The series of processes up to 6 are carried out by the first arithmetic circuit 8 in the control bag W7.
However, when a microcomputer is used as the control device 7 as in this embodiment,
Data on the engine required horsepower P corresponding to the vehicle speed deviation may be stored in a read-only memory (ROM), or
Alternatively, the engine required horsepower P may be directly determined by map search from both the target NWO and actual vehicle speed NW data without calculating the vehicle speed deviation. Step 17 to Step 19
is a process performed by the second arithmetic circuit 9. First, in step 17, the actual vehicle speed NW from the vehicle speed sensor 5 is taken in again, and then, based on this actual vehicle speed NW and the engine required horsepower P calculated in step 16, In step 18, the gear ratio e
is calculated and commanded to the continuously variable transmission 3, and then in step 19, the fuel supply amount Q is calculated and this is sent to the fuel supply device 2.
command. When the process of step 19 is completed, the process returns to step 12 and the above process is repeated.

Here, the method of calculating the gear ratio e and the fuel supply IQ in steps 18 and 19 will be explained.

FIG. 3 is a diagram showing a performance curve of the engine 1, in which the horizontal axis shows the engine speed NE and the vertical axis shows the engine torque TE. In addition, each curve shown by a broken line is an equal engine output horsepower curve (
10,20,30,40゜50.60,70 PS)
, each curve shown by a thin solid line is an equal fuel consumption rate curve (200
・210・220・! )240.260,
300 G/PS-H), and the curve shown by the dashed line is the maximum torque curve. The maximum torque curve shows the maximum torque at each engine speed, and the engine 1 cannot generate a torque larger than this maximum torque curve, and from the equal engine output horsepower curve and the equal fuel consumption rate curve, a certain engine output horsepower can be calculated. The lowest fuel consumption rate curve is obtained by finding the lowest fuel consumption rate over the entire range of engine output horsepower, and connecting each point is the minimum fuel consumption rate curve shown by the thick solid line. By operating the engine 1, it is possible to always operate the engine 1 with the minimum fuel consumption amount for the engine required horsepower P. Therefore, the target engine speed NER and the target engine torque TER are uniquely determined by the minimum fuel consumption rate curve for the engine required horsepower P calculated by the first calculation circuit 8, and the target engine speed NER and the actual vehicle speed NW are uniquely determined by the minimum fuel consumption rate curve. From this, the gear ratio e of the continuously variable transmission 3 can be calculated using the following equation.

Here, h is a constant and varies depending on the vehicle, and the actual vehicle speed NW is input separately when calculating the engine required horsepower P and when calculating the gear ratio e and fuel supply amount Q (see Figure 3). Since the actual vehicle speed NW fluctuates very slowly compared to the responses of the continuously variable transmission 3 and the engine 1, it can be considered to be constant when performing a series of calculations. Next, in a normal engine, since engine torque and fuel supply amount are almost proportional, fuel supply -uQ can be calculated by the following equation.

Q=TERXk Here, k is a proportionality constant, and has a unique value depending on the engine model. Furthermore, if the fuel supply amount and engine torque are not proportional, the fuel supply JilQ may be calculated using the following equation as a unique function of the engine torque.

Q"f (TER) As described above, by calculating the gear ratio e and the fuel supply amount Q based on the engine required horsepower P and the actual vehicle speed NW corresponding to the deviation between the target vehicle speed NWO and the actual vehicle speed NW, Even if the running load fluctuates, the actual vehicle speed NW remains the target vehicle speed NWO.
Since the continuously variable transmission 3 and the fuel supply device 2 can be controlled so that the following occurs, constant speed driving is possible.

In the above embodiment, the first and second arithmetic circuits 8 and 9 are configured by microcomputers, but it is clear that they can be easily configured by an arithmetic equivalent circuit using an OP amplifier.

(Effects of the Invention) As explained above, the present invention consists of a fuel supply device that controls the amount of fuel supplied using external electricity (no. In an engine vehicle equipped with a transmission, a target vehicle speed is commanded by a target vehicle speed command device, an actual vehicle speed is detected by a vehicle speed sensor, and a first calculation circuit calculates the engine required horsepower based on the deviation between the target vehicle speed and the actual vehicle speed. A second calculation circuit calculates the gear ratio and fuel supply amount based on the actual vehicle speed and engine required horsepower to control the continuously variable transmission and fuel supply system. By focusing on the deviation of This has the effect of making it possible.

[Brief explanation of drawings]

The first is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a flow chart for explaining the operation of an embodiment of the present invention, and FIG. 3 is a diagram showing an engine performance curve. be. DESCRIPTION OF SYMBOLS 1... Engine, 2... Fuel supply device 3... Continuously variable transmission, 4... Axle. 5...Vehicle speed sensor, 6...Target vehicle speed command device, 8.
...first arithmetic circuit, 9...second arithmetic circuit. Sentry

Claims (1)

[Claims] (1) Target for vehicles equipped with an engine equipped with a fuel supply device that controls the amount of fuel supplied using external electrical signals, and a continuously variable transmission whose gear ratio changes continuously based on external electrical signals. a target vehicle speed command device that commands the traveling speed as a target vehicle speed signal; a vehicle speed sensor that detects the actual traveling speed as the actual vehicle speed signal; a first arithmetic circuit that calculates the engine required horsepower by using the actual vehicle speed signal and the engine required horsepower signal and outputs it as an engine required horsepower signal; and calculates the fuel supply amount and the gear ratio using the actual vehicle speed signal and the engine required horsepower signal as input signals, and outputs the calculation results as an electrical signal. A speed control device for an engine vehicle equipped with a continuously variable transmission, comprising: a second arithmetic circuit that outputs signals to the fuel supply device and the continuously variable transmission, respectively.