JPS6233087B2 - - 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, the engine is controlled primarily by controlling the air-fuel ratio and ignition timing so as to obtain the intended operating performance.

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 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, similar problems have arisen in transmissions because they are 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 of a vehicle. A power transmission device including a continuously variable transmission 3 and the like is connected to the engine 1 via a connecting shaft 2, and a drive wheel 4 is further connected to the engine 1. The continuously variable transmission 3 can continuously change the gear ratio. 5 is an accelerator pedal operated by the driver of the vehicle; 6 is a detector that detects the amount of operation of the accelerator pedal 5 and outputs an engine output command signal and an engine rotation speed command signal of a corresponding magnitude; The detector 6 forms a command means. Reference numeral 7 denotes a throttle valve of a carburetor or mixer of the engine, and the throttle valve 7 adjusts the amount of air and fuel taken into the engine 1 in conjunction with the accelerator pedal 5. The throttle valve 7 forms a first engine power regulating means. Reference numeral 8 denotes an air flow sensor that measures the amount of air taken into the engine, 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 6 and the output signal of the air flow sensor 8 and outputs a difference signal therebetween;
0 is a throttle valve that adjusts the amount of air taken into the engine 1; 11 is a throttle valve adjustment device that adjusts the throttle valve 10 in accordance with the output of the engine control device 9; A second engine power adjustment means is formed. 12 is an engine rotation speed sensor provided on the connecting shaft 2 to measure the rotation speed of the engine 1;
13 is an adder; 14 is a converter that converts the output signal of the engine control device 9 into a signal suitable for the adder 13; the adder 13 converts the engine rotation speed command signal from the detector 6 and the output signal of the converter 14; is input and outputs the sum signal. 15 is a transmission control device which receives the output signals of the engine rotation speed sensor 12 and the adder 13 and outputs a difference signal; 16 is a gear ratio of the continuously variable transmission 3 according to the output signal of the transmission control device 15; This is a gear ratio adjustment device that adjusts the

Next, the operation of the apparatus having the above configuration will be explained.
First, when the driver of the vehicle depresses the accelerator pedal 5, the throttle valve 7 operates in conjunction with this, and the detector 6 also outputs an engine output command signal and an engine rotation speed command signal in response to the operation of the accelerator pedal 5. issue. This engine output command signal is applied to the throttle valve adjustment device 11 via the engine control device 5, and the throttle valve 10 is adjusted accordingly.
is operated to adjust the intake air amount of the engine 1. Engine output corresponds to the flow rate of the air-fuel mixture, so it also corresponds to the air flow rate. Therefore, by measuring the air flow rate to the engine 1 using the air flow rate sensor 8, the engine output can be measured. The output of the air flow sensor 8 is fed back to the engine control device 9, and the throttle valve 10 is adjusted so that the output signal of the air flow sensor 8 becomes equal to the engine output command signal.

On the other hand, the engine rotation speed command signal output from the detector 6 is input to the adder 13 together with a signal obtained by converting the signal from the engine control device 9 by the converter 14, and is added. The output signal from the adder 13 is applied to the gear ratio adjusting device 16 via the transmission control device 15, and the gear ratio of the continuously variable transmission 3 is adjusted accordingly. The output signal of the engine speed sensor 12 is applied to the transmission control device 15, and the transmission control device 15 uses a gear ratio adjustment device so that the signal from the adder 10 and the signal from the engine speed sensor 12 become equal. Add a signal to 16.

Next, if we examine the above operation in more detail in a transient manner, for example, if we now press the accelerator pedal 5 to accelerate, the opening of the throttle valve 7 increases in conjunction with the accelerator pedal 5, and at the same time the engine signal from the detector 6 increases. The output command signal and the engine speed command signal increase. The engine output command signal is given to the engine control device 9, but since the output of the engine 1 does not suddenly increase, there is a difference between the signal from the air flow sensor 8 and the throttle valve adjustment device 11. 10 is controlled so that the opening degree becomes large. As the intake air amount of the engine 1 increases and the rotational speed of the engine 1 increases, the engine output also increases, and the air flow sensor 8
The output signal gradually approaches the engine output command signal.

On the other hand, immediately after the accelerator pedal 5 is depressed, the engine speed command signal increases and the output signal of the engine control device 9 also increases, so the output signal of the adder 13 further increases. However, since the rotation speed of the engine 1 does not suddenly increase, a large difference occurs between the output signal of the adder 13 and the output signal of the engine rotation speed sensor 12.
output increases, and the continuously variable transmission 3 is controlled via the gear ratio adjustment device 16 so that the gear ratio increases. To increase the vehicle speed, it is first necessary to increase the torque of the propulsion shaft, and for this purpose it is necessary to increase the gear ratio. Now, as the gear ratio increases as described above, the vehicle speed increases, and as a result, the rotational speed of the engine 1 increases and the engine output also increases. Therefore, the output of the air flow sensor 8 increases and the output of the engine control device 9 decreases. Therefore, the output signal of the adder 13 approaches the engine rotational speed command signal, and the output of the engine rotational speed sensor 12 increases, so the signal to the gear ratio adjustment device 16 becomes smaller and the gear ratio also becomes smaller. In this way, when the vehicle speed suddenly accelerates, the gear ratio automatically increases to obtain a large torque, and as the vehicle speed increases, the gear ratio automatically decreases. Therefore, engine output is efficiently transmitted to the drive wheels, and fuel consumption can be reduced.

In the above embodiment, the air flow rate sensor 8 is used as the engine output measuring means, but a sensor that measures the amount of fuel taken into the engine may also be used. Alternatively, a sensor may be provided to measure the intake air pressure of the engine, and the engine output may be measured from the product of the intake air pressure and the engine speed. Furthermore, a sensor may be provided to measure the shaft torque of the engine, and the engine output may be measured from the product of the shaft torque and the engine rotational speed.

Further, by providing a suitable map with a program calculation function in the detector 6 or converter 14, the relationship between engine output and engine frequency is controlled so that it follows the minimum fuel efficiency curve shown by the dotted line in Fig. 2. You can also. For example, the detector 6 is configured so that the engine output command signal and the engine rotational speed command signal have a relationship along a minimum fuel consumption curve.

As described above, in the present invention, in addition to the first throttle valve that adjusts the engine output in conjunction with the command means, the engine is controlled by the difference signal between the engine output command signal of the command means and the output signal of the engine output measurement means. A second throttle valve is provided to control the output, and the speed of the power transmission device is changed by the difference signal between the signal obtained by adding the engine rotation speed command signal of the command means to the difference signal and the output signal of the engine rotation speed measurement means. A gear ratio adjusting means for adjusting the ratio is provided.
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, and at constant speed at high speeds, the gear ratio automatically increases. Since the gear ratio is automatically reduced, there is no need to increase the engine speed unnecessarily. As 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, 3...Continuously variable transmission, 4...Drive wheel, 5...Accelerator pedal, 6...Detector,
7, 10...throttle valve, 8...air flow rate sensor, 9...engine control device, 11...throttle valve adjustment device, 12...engine rotation speed sensor,
15... Transmission control device, 16... Gear ratio adjustment device.

Claims (1)

[Scope of Claims] 1. In a vehicle in which engine output is transmitted to drive wheels via a continuously variable transmission ratio power transmission device, a command means for a vehicle driver to command engine output and engine rotation speed; a first throttle valve that adjusts engine output in conjunction with a command means;
an engine output measuring means for measuring the engine output;
a second throttle valve that adjusts the engine output independently of the throttle valve; an engine rotation speed measuring means for measuring the engine rotation speed; and a signal obtained by adding the difference signal to the engine rotation speed command signal of the command means. 1. A power system control device for a vehicle, comprising a gear ratio adjusting means for adjusting a gear ratio of a power transmission device according to a difference signal between the output signal and the output signal of an engine rotation speed measuring means. 2. The vehicle power system control device according to claim 1, wherein the engine output measuring means is constituted by an engine intake air amount measuring device. 3. The vehicle power system control device according to claim 1, wherein the engine output measuring means is constituted by an engine intake fuel amount measuring device. 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.