JPS6233090B2 - - 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 FIG. 1, using the negative pressure of the intake manifold as a parameter. ), if the intake pressure of the air and fuel mixture is constant, the output torque will change depending on the rotation speed, and the output torque will be small at low and high speed rotations, and will reach its maximum at an appropriate rotation speed in between. Become. 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 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, and the continuously variable transmission 3 is connected to a drive 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; the accelerator pedal 6 and the detector 7 form a command means. . Reference numeral 8 denotes an air flow rate sensor that measures the intake air flow rate of the engine 1, and the air flow rate sensor 8 forms engine output measuring means. Reference numeral 9 denotes an engine control device which receives the output signal of 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, and adjusts the engine output. The throttle valve 10 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 response to the output of the engine control device 9; 12 is a function generator that generates an engine rotation speed command signal in response to the output of the air flow sensor 8; A converter 13 converts the output signal of the engine control device 9 into a signal suitable for the adder 14. The adder 14 receives the outputs of the function generator 12 and the converter 13, and outputs a sum signal. 15 is an engine rotation speed sensor provided on the output shaft 2 and measures the engine rotation speed; 16 is a transmission control device that receives the output signals of the adder 14 and the engine rotation speed sensor 15 and outputs a difference signal; Reference numeral 17 denotes 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 16.

In the above device, when the driver depresses the accelerator pedal 6, the detector 7 detects the state of depressing the accelerator pedal 6 and senses the driver's intention, such as whether to accelerate suddenly or what the vehicle speed is. Accordingly, an engine output command signal is output. This signal is given to the throttle valve adjustment device 11 via the engine control device 9, and the throttle valve adjustment device 12 adjusts the opening degree of the throttle valve 10 and adjusts the engine output. 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 output signal of the detector 7. controlled to be equal.

On the other hand, an engine rotation speed command signal is generated from the function generator 12 in response to the output signal of the air flow sensor 8, and the output of the engine control device 9 is converted by the converter 13 into a signal suitable for the adder 14. , the output signals of the function generator 12 and the converter 13 are added in the adder 14, and this added signal and the output signal of the engine rotation speed sensor 15 are compared in the transmission control device 16 so that the two become equal. A signal is sent from the transmission control device 16 to the speed ratio adjustment device 17 so that the speed change ratio is adjusted accordingly.

For example, if you now try to accelerate by depressing the accelerator pedal 6, the engine output command signal from the detector 7 will first increase, causing a difference between the output signal from the air flow sensor 8 and the engine control device 9. A signal is sent to the throttle valve adjusting device 11 to increase the opening degree of the throttle valve 10.
However, since the vehicle speed does not suddenly increase, the engine speed also does not increase, and the engine output does not increase either. In order to increase the vehicle speed, it is necessary to increase the torque of the drive shaft 4, and for this purpose, the gear ratio of the continuously variable transmission 3 is controlled based on the engine rotation speed command signal. A function generator 12 corresponds to the output of the air flow sensor 8.
An engine rotational speed command signal is applied to the adder 14 from the adder 14, and an output signal of the converter 13 corresponding to the output of the engine control device 9 is applied to the adder 14.
Since the output signal of the converter 14 increases as the accelerator pedal 6 is depressed, the output signal of the adder 14 increases, and since the output of the engine rotation speed sensor 15 does not suddenly increase, the transmission control device 16 determines the gear ratio. A large signal is applied to the adjustment device 17, and the gear ratio of the continuously variable transmission 3 increases. As a result, the torque of the drive shaft 4 increases, so the vehicle speed increases, and the engine rotational speed increases, so the engine output also increases. Therefore, the output of the air flow sensor 8 increases, the output of the engine control device 9 gradually approaches zero, and the engine output becomes stable. Further, the output of the adder 14 decreases and approaches the engine speed command signal, and the output of the engine speed sensor 15 increases, so the output of the transmission control device 16 approaches zero, and the gear ratio gradually decreases and becomes stable. . By controlling the throttle valve 10 and the continuously variable transmission 3 in this way, the engine output and engine speed are controlled to correspond to the depression of the accelerator pedal 6, and the gear ratio increases during sudden acceleration to reduce the vehicle speed. It is controlled so that it becomes smaller as it rises.

Incidentally, in the above control process, fuel consumption and drivability are not necessarily optimized. Therefore, in order to optimize the fuel consumption, it is best to control the engine output and engine speed so that they follow the minimum fuel consumption curve shown by the dotted line in Figure 2. It is preferable that the function generator 12 is provided with a calculation function based on a map or a program in advance so that the engine output command signal and the engine rotation speed command signal change over time along the minimum fuel consumption curve. Further, in the above embodiment, the air flow rate sensor 8 is used as the engine output measuring means, but a fuel flow rate sensor that measures the intake fuel flow rate of the engine 1 may also be used.

As described above, in the present invention, the driver commands the engine output, the measuring means for measuring the engine output and the engine speed, and the engine speed command signal corresponding to the output signal of the engine output measuring means. A function generating means, an engine output adjusting means, a speed ratio adjusting means, etc. are provided, and the throttle valve is controlled according to the difference signal between the engine output command signal and the engine output measurement signal, and the output signal of the function generating means is The gear ratio adjusting means is controlled in accordance with the difference signal between the signal added with the difference signal and the engine rotational speed measurement signal. 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 is automatically increased to obtain a large torque, smoothing the sudden acceleration, and increasing the vehicle speed. As the speed increases, the gear ratio automatically decreases, so there is no need to unnecessarily increase the engine speed. As a result, the vehicle can be driven efficiently as intended by the driver and 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... Output shaft, 3... Continuously variable transmission, 4... Drive shaft, 5... Drive wheel, 6... Accelerator pedal, 7... Detector, 8... Air flow sensor, 9... Engine control device, 10... Throttle valve, 11... Throttle valve adjustment device, 12...
Function generator, 13... converter, 14... adder,
15... Engine speed sensor, 16... Transmission control device, 17... Gear ratio adjustment device.

Claims (1)

[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, an engine output measurement means for measuring engine output, An engine rotation speed measurement means for measuring engine rotation speed, a function generation means for generating an engine rotation speed command signal in response to an output signal of the engine output measurement means, and an output signal of the command means and an output signal of the engine output measurement means. a throttle valve that adjusts the engine output according to the difference signal between the two; and a throttle valve that adjusts the engine output according to the difference signal between the output signal of the function generating means and the output signal of the engine rotation speed measuring means. 1. A power system control device for a vehicle, comprising a gear ratio adjusting means for adjusting a gear ratio.