JPS6233091B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle power system control device that comprehensively controls a vehicle engine and transmission.

Generally, in an engine, the relationship between its rotational speed and output torque is as shown in Figure 1 (the negative pressure of the intake manifold is used as a parameter). The output torque changes depending on the number of rotations, and the output torque is small at low speed rotation and high speed rotation, and the output torque is maximum at an appropriate rotation speed between them. Furthermore, as the suction pressure of the air-fuel mixture increases, the output torque also increases. A in FIG. 1 shows the case where the throttle valve is fully open and the suction pressure of the air-fuel mixture is at its highest.

Furthermore, the output torque of the engine also changes depending on the mixture ratio of air and fuel, that is, the air-fuel ratio, and the ignition timing. For this reason, engine control is performed primarily by controlling the air-fuel ratio and ignition timing.

However, in conventional vehicle power system control, engine control and transmission control are performed separately, and engine control is performed only by the engine, so if the transmission gear ratio is not appropriate, the power system will not function properly. There was a problem that the performance could not be demonstrated. For example, when you want to rapidly accelerate a vehicle, even if you increase the output torque of the engine, if the gear ratio of the transmission is small, sufficient torque will not be obtained and only fuel consumption will increase. Furthermore, if the gear ratio is increased when the vehicle wants to run at a constant high speed, the engine rotational speed will increase, which will also increase the amount of fuel consumed. on the other hand,
A similar problem arose in the transmission because it was individually controlled.

The present invention has been made in an attempt to eliminate the above-mentioned problems, and it is possible to drive the vehicle efficiently with minimum fuel consumption by comprehensively controlling the engine and transmission of the vehicle. The purpose of the present invention is to provide a vehicle power system control device that can perform the following tasks.

Figure 2 shows an example of fuel consumption per unit of output power of the engine.The solid line is the equal fuel consumption curve, and the dotted line is the line that vertically cuts the equal fuel consumption curve as the engine speed increases, and the lowest This is the fuel consumption curve. Fuel consumption decreases as you move toward the center of the isofuel consumption curve. When trying to set the output torque and rotation speed on the output side of the transmission to a certain value, various combinations of the engine condition and the gear ratio of the transmission can be considered, but the control device according to the present invention can minimize fuel consumption. It controls the engine condition and gear ratio so that the

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 3, reference numeral 1 denotes an engine, and the engine 1 is connected to a continuously variable transmission 3 that can continuously change the gear ratio via its output shaft 2. The continuously variable transmission 3 is connected to a propulsion shaft 4. The drive wheels 5 are connected via, for example. 6 is an accelerator pedal operated by the driver of the vehicle; 7 is a detector that detects the amount of operation of the accelerator pedal 6 and outputs a corresponding engine output command signal and engine rotation speed command signal; This forms a command means. Reference numeral 8 denotes an air flow sensor for measuring the intake flow rate of the engine 1, and the air flow sensor 8 forms engine output measuring means. Reference numeral 9 denotes an engine control device which receives the engine output command signal from the detector 7 and the output signal of the air flow sensor 8 and outputs a difference signal therebetween; 10;
is a throttle valve of the carburetor or mixer of the engine 1, and the throttle valve 10 adjusts the amount of air and fuel taken into the engine 1. Throttle valve 1
0 is not interlocked with the accelerator pedal 6. 11 is a throttle valve adjusting device that adjusts the opening degree of the throttle valve 10 in accordance with the output of the engine control device 9;
2 is an engine rotation speed sensor provided on the output shaft 2 and measures the engine rotation speed; 13 is an engine rotation speed command signal from a detector 7 and an engine control device 9
14 is a transmission control device which receives the output signal of the adder 13 and the output signal of the engine rotation speed sensor 12 and outputs a difference signal thereof; 15 is a gear ratio adjustment device that adjusts the gear ratio of the continuously variable transmission 3 in accordance with the output of the transmission control device 14.

In the above device, when the driver depresses the accelerator pedal 6, the detector 7 detects the state of depressing the accelerator pedal 1 and detects the driver's intention, such as whether to accelerate suddenly or what the vehicle speed is.
In response to this, an engine output command signal and an engine rotation speed command signal are output. These signals are sent to the engine 1 via a feedback control circuit, respectively.
and a device for controlling the continuously variable transmission 3. First, an engine output command signal is applied to the engine 1 via the engine control device 9 to the throttle valve adjusting device 11 to open the throttle valve 10 . In the case of sudden acceleration, a command is also given to increase the amount of fuel. On the other hand, since the engine output corresponds to the mass of the intake air-fuel mixture, the engine output can be measured, for example, by measuring the air flow rate or fuel flow rate to the engine 1. Therefore, the engine output can be detected by the output of the air flow sensor 8, and this output signal is fed back to the engine control device 9, and the throttle valve 10 detects the output signal of the air flow sensor 8 and the engine output from the detector 7. Control is performed so that the command signals are equal to each other. Further, the engine rotation speed command signal from the detector 7 and the output signal of the engine control device 9 are added in an adder 13, and the difference signal between this added signal and the output signal of the engine rotation speed sensor 12 is sent to the gear ratio adjustment device. 15, and the gear ratio of the continuously variable transmission 3 is controlled according to the difference signal.

Now, when you try to accelerate by depressing the accelerator pedal 6, the engine output command signal and the engine speed command signal from the detector 7 increase, but since the engine speed does not suddenly increase, the air flow sensor 8 The output of the engine does not suddenly increase, and a difference occurs between the engine output command signal and the output signal of the air flow sensor 8, and the engine control device 9 sends the throttle valve adjustment device 11 to increase the opening degree of the throttle valve 10. A signal is sent. On the other hand, since both the engine speed command signal and the output signal of the engine control device 9 increase, the output signal of the adder 13 becomes even larger, and the output signal of the engine speed sensor 12 does not rise suddenly, so the transmission control device 14
A signal is applied to the gear ratio adjusting device 15 from the control unit 15 to increase the gear ratio of the continuously variable transmission. In order to increase the vehicle speed, it is necessary to increase the torque of the propulsion shaft 4, but now that the gear ratio has been increased, the torque of the propulsion shaft 4 increases, and the vehicle speed increases. As a result, the rotation speed and output of the engine 1 increase,
As the output signal of the air flow rate sensor 8 increases, the output signal of the engine control device 9 gradually approaches zero, and the engine output becomes stable. Further, the output signal of the adder 13 approaches the engine rotation speed command signal, and the output signal of the engine rotation speed sensor 12 increases, so the output signal of the transmission control device 14 also approaches zero.
The gear ratio becomes smaller and stabilizes at the command value. By controlling the throttle valve 10 and the continuously variable transmission 3 in this way, the engine output and rotation speed are controlled according to the depression of the accelerator pedal 6, and the gear ratio is large during sudden acceleration and small during constant speed operation. controlled so that

In the above embodiment, the air flow sensor 8 is used as the engine output measuring means, but a fuel flow sensor that measures the intake fuel flow rate of the engine 1 may also be used. Furthermore, in the above control process, the fuel consumption may not always be optimal. For this purpose, for example, the engine output and engine speed may be controlled by a computer so that they change along the minimum fuel consumption curve shown by the dotted line in FIG. By making the engine output command signal and the engine rotational speed command signal change over time along the minimum fuel efficiency curve, it is possible to control the fuel consumption to be optimal.

As described above, in the present invention, a command means for commanding engine output and engine speed, an engine output measuring means, a throttle valve, an engine speed measuring means, a gear ratio adjusting means, etc. are used to control the engine output command signal and the engine speed. The engine output is controlled according to the difference signal between the output signal of the engine output measurement means and the difference signal between the signal obtained by adding the difference signal to the engine rotation speed command signal and the output signal of the engine rotation speed measurement means. Controls the gear ratio.
Therefore, it is possible to control the engine output and the gear ratio at the same time. For example, when accelerating suddenly, the gear ratio automatically increases and a large torque is obtained, allowing sudden acceleration to be performed smoothly, or at a constant speed at high speed. During operation, the gear ratio is automatically reduced so that the engine speed does not need to be increased unnecessarily. Such a result,
The vehicle can be operated efficiently with minimum fuel consumption.

[Brief explanation of the drawing]

FIG. 1 is an engine output characteristic diagram, FIG. 2 is an engine fuel consumption characteristic diagram, and FIG. 3 is a configuration diagram of a vehicle power system control device according to the present invention. 1...Engine, 2...Engine output shaft, 3
... Continuously variable transmission, 4... Propulsion shaft, 5... Drive shaft,
6... Accelerator pedal, 7... Detector, 8... Air flow rate sensor, 9... Engine control device, 10...
... Throttle valve, 11... Throttle valve adjustment device, 12... Engine rotation speed sensor, 13... Adder, 14... Transmission control device, 15... Gear ratio adjustment device.

Claims (1)

[Scope of Claims] 1. In a vehicle in which engine output is transmitted to a drive shaft via a continuously variable transmission ratio power transmission device, a command means for a vehicle driver to command engine output and engine rotation speed; an engine output measuring means for measuring engine output; a throttle valve for adjusting the engine output according to a difference signal between the engine output command signal of the command means and the output signal of the engine output measuring means; and an engine rotation for measuring the engine speed. speed ratio adjusting means for adjusting the speed ratio of the power transmission device in accordance with a difference signal between a signal obtained by adding the difference signal to the engine speed command signal of the commanding means and an output signal of the engine speed measuring means; A vehicle power system control device comprising: 2. The power system control device for a vehicle according to claim 1, wherein the engine output measuring means is constituted by an engine intake air flow rate measuring device that measures the intake air flow rate of the engine. 3. The power system control device for a vehicle according to claim 1, wherein the engine output measuring means is constituted by an engine intake fuel flow rate measuring device that measures the intake fuel flow rate of the engine. 4. According to any one of claims 1 to 3, wherein the command means is configured such that the engine output command signal and the engine rotation speed command signal have a relationship along a minimum fuel consumption curve. A power system control device for the vehicle described above.