JPS6233089B2 - - 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 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,
Similar problems arose in transmissions as well, as they were 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. . 8 is a signal conversion device that converts the engine output command signal from the detector 7 into an engine rotation speed command signal; 9 is an air flow sensor that measures the intake air flow rate of the engine 1; the air flow sensor 9 forms engine output measurement means. do. 10 is an engine control device that receives the output signal of the detector 7 and the output signal of the air flow sensor 9 and outputs a difference signal; 11;
is a throttle valve of the carburetor or mixer of the engine 1, and the throttle valve 11 adjusts the amount of air and fuel taken into the engine 1. Throttle valve 1
1 is not interlocked with the accelerator pedal 6. 12 is a throttle valve adjusting device that adjusts the opening degree of the throttle valve 11 in accordance with the output of the engine control device 10;
13 is an adder that receives the output signal of the signal conversion device 8 and the output signal of the engine control device 10 and outputs a sum signal thereof; and 14 is an engine rotation speed sensor provided on the output shaft 2 to measure the engine rotation speed. ,
15 is a transmission control device which receives the output signal of the adder 13 and the output signal of the engine rotation speed sensor 14 and outputs a difference signal; 16 is a continuously variable transmission corresponding to the output of the transmission control device 15; This is a gear ratio adjustment device that adjusts the gear ratio of No. 3.

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 12 via the engine control device 10, and the throttle valve adjustment device 12 adjusts the opening degree of the throttle valve 11 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 9, and this output signal is fed back to the engine control device 10, and the throttle valve 11 detects the output signal of the air flow sensor 9 and the output signal of the detector 7. controlled to be equal.

On the other hand, the engine output command signal from the detector 7 is converted into an engine rotation speed command signal in the signal conversion device 8, and this command signal and the engine control device 1
0 output signal is added in the adder 13,
This addition signal and the output signal of the engine rotation speed sensor 14 are compared in the transmission control device 15,
A signal is sent from the transmission control device 15 to the speed ratio adjustment device 16 so that the speed change ratio is adjusted so that both signals are equal.

For example, if you try to accelerate by depressing the accelerator pedal 6, first the engine output command signal from the detector 7 will increase, and a difference will occur between it and the output signal of the air flow sensor 9, and the engine control device 10 will A signal is sent to the throttle valve adjusting device 12 to increase the opening degree of the throttle valve 11. However, since the vehicle speed does not suddenly increase, the output of the air flow sensor 9 also does not increase suddenly. Further, the engine speed command signal from the signal conversion device 8 also increases, and the input signals of the adder 13 also increase, so that the output signal of the adder 13 further increases and is applied to the transmission control device 15. However, since the output of the engine speed sensor 14 does not suddenly increase, a large signal is applied from the transmission control device 15 to the gear ratio adjusting device 16, and the gear ratio of the continuously variable transmission 3 increases. As the gear ratio increases in this manner, the torque of the drive shaft 4 increases, and the vehicle speed increases. Therefore, the engine speed increases, the air flow rate also increases, and the engine output also increases. Therefore, the output of the air flow sensor 9 increases, the output of the engine control device 10 gradually approaches zero, and the engine output becomes stable. Further, the output signal of the adder 13 decreases and approaches the engine speed command signal, and the output signal of the engine speed sensor 14 increases, so the output of the transmission control device 15 approaches zero, and the gear ratio becomes smaller. Stabilize. In this way, the throttle valve 11
By feedback-controlling the continuously variable transmission 3, the engine output and engine speed are controlled to correspond to the depression of the accelerator pedal 6, and the gear ratio is controlled to be large during sudden acceleration and small during constant speed operation. be done.

Incidentally, in the above control process, the fuel consumption amount is not necessarily optimized. For this reason,
For example, the signal conversion device 8 is programmed in advance so that the engine output command signal and the engine speed command signal have a relationship along the minimum fuel consumption curve, and the engine output, engine speed, and gear ratio are controlled accordingly. By doing so, the fuel consumption can be controlled to be reliably minimized. Further, in the above embodiment, the air flow rate sensor 9 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 signal conversion means converts the output signal of the command means into an engine rotation speed command signal, and the measurement means measures the engine output and rotation speed, respectively. , a throttle valve, a gear ratio adjustment means, etc. are provided, and the engine output adjustment means is controlled according to a difference signal between the engine output command signal and the engine output measurement signal, and the difference signal is added to the output signal of the signal conversion means. The gear ratio adjusting means is controlled according to the difference signal between the signal and the engine rotation 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. Such 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. DESCRIPTION OF SYMBOLS 1... Engine, 2... Output shaft, 3... Continuously variable transmission, 4... Drive shaft, 5... Drive wheel, 6... Accelerator pedal, 7... Detector, 8... Signal conversion device, 9...Air flow rate sensor, 10...Engine control device, 11...Throttle valve, 12...Throttle valve adjustment device, 13...Adder, 14...Engine speed sensor, 15...Transmission control device, 1
6... Gear ratio adjustment device.

Claims (1)

[Claims] 1. In a vehicle in which engine output is transmitted to the drive shaft via a power transmission device with a continuously variable gear ratio, a command means for the vehicle driver to command the engine output, and an output signal of the command means as an engine rotation speed command signal. a signal conversion means for converting the output signal into a signal, an engine output measurement means for measuring the engine output, an engine rotation speed measurement means for measuring the engine rotation speed, and a difference signal between the output signal of the command means and the output signal of the engine output measurement means. a throttle valve that adjusts the engine output accordingly, and a gear ratio of the power transmission device that adjusts the gear ratio of the power transmission device according to a difference signal between a signal obtained by adding the difference signal to the output signal of the signal converting means and an output signal of the engine rotation speed measuring means. 1. A power system control device for a vehicle, comprising a gear ratio adjusting means.