JPS63219852A - Automatic control method in carburetor - Google Patents

Abstract

PURPOSE:To promote the compactness of a heat sink and to ensure the stable operation of a carburetor, by controlling feedback voltage in accordance with a motor speed pulse by a D/A converter serving for the reference voltage to a comparator. CONSTITUTION:An electronic control unit 3 is electrically connected to a valve opening sensor switch 7, valve opening sensor 11, engine speed sensor 12 and an engine stop circuit 13. The electronic control unit 3 controls a carburetor valve shaft 5 rotating in its closing direction by a step motor 4 so as to obtain a predetermined speed, performing a speed governing control. Inputting voltage Vref to a D/A converter 14 by a data bus 17, the voltage Vref is supplied performing a current control in accordance with a motor required speed. In this way, by promoting the compactness of a heat sink, a carburetor enables stable operation to be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic control method for a carburetor for an internal combustion engine having a regulating side MS function.

[Conventional technology]

Conventionally, it is known that engine rotation is controlled by operating a step motor with a controller to adjust the throttle valve opening of the carburetor. , is a device that can be remotely controlled electrically via an electronic control unit and a step motor, and as shown in FIG. Detected with [V, = II
RI) L/, reference voltage Vref and comparator 1
5, and ■, when ≧Vref, the transistor 16 is turned OFF to cut the current, and when VF<Vref, the transistor 16 is turned ON, and the current flowing to the mork coil 41 is controlled by chopping control that causes the L current to flow. There is.

[Problem that the invention seeks to solve]

However, in such conventional control methods,
At the characteristic point where the characteristics of the required torque (load) of the step motor and the generated torque of the motor intersect as shown in Figure 5 ■, torque can be obtained efficiently, but in the region where the motor speed is low, for example at the L+ point, the T width The current corresponding to the extra torque shown in is wasted, that is, there is power loss in the shaded area, so a transistor with a larger capacity must be used, which generates more heat, and the heat sink of the heat dissipation plate must also be larger. was there.

The present invention aims to eliminate these conventional drawbacks, and uses electronic control to control the current according to the required speed of the step motor, thereby reducing power loss, significantly reducing heat generation, and reducing the size and cost of each transistor and heat sink. The purpose of the present invention is to provide a highly reliable control method for a vaporizer that greatly improves operability.

[Means for solving problems]

When controlling the throttle valve of a carburetor using a drive step motor, the present invention provides electronic data on engine rotation and throttle angle using a rotation sensor and a throttle valve opening sensor after initial setting by the step motor. The input is input to the control unit and the ignition is controlled accordingly, and the current flowing to the step motor coil is detected by a feedback resistor, compared with a reference voltage by a comparator, and the transistor is ON-OFF controlled to energize the step motor coil. In devices that control current, the feedback voltage is controlled by a D/A converter so that the optimal current for the required output can be supplied to each step motor coil according to the motor speed pulse calculated and set in advance, and the reference voltage is set to the comparator. This is an automatic control method for a vaporizer characterized by using voltage.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. In this embodiment, a throttle valve 2 of a carburetor 1 is opened and closed by a step motor 4 controlled by an electronic control unit 3 via a valve shaft 5. The motor output shaft 51 and the valve shaft 5 are connected by a universal joint 6, and an output signal is transmitted to the child control unit 3 by a valve opening detection switch 7 which is operated by pressing the valve shaft 5. One valve shaft 5 is equipped with a slip joint mechanism 8 and a throttle lever 9, and a valve opening sensor 1) is provided via a universal joint 10.
The output signal of this valve opening sensor 1) is sent to the electronic control unit 3. That is, in order to detect the input angle of the throttle, D
/A converter 14 and compares it with current feedback resistance R1 (Ω) by comparator 15 and outputs it to transistor 16.
ON-OFF control. The electronic control unit 3 receives the rotation signal from the engine rotation sensor 12 and calculates it with the valve opening signal, and uses the output signal to control the engine stop circuit 13 in addition to the drive circuit for the step motor 4. It looks like this.

The step motor 4 rotates forward and backward by a fixed angle in response to the output signal of the transistor 16 of the electronic control unit 3, and the optimum current for the required output is applied to each step motor coil 41 according to the motor speed pulse calculated and set in advance. Connect the feedback voltage to D/A to supply
The converter 14 controls the reference voltage to the comparator 15 and compares it with the voltage V detected by the feedback resistor R+ (Ω), turning the transistor 16 ON -OF.
The current flowing to the step motor coil 41 is controlled by F control.

Note that the drive signal for the step motor 4 is a reference voltage V ref corresponding to the required pulse speed at the start of the control output.
It is preferable to output the motor drive pulse after the output cassette is output from the A converter 14, and the step motor 4 is connected to the engine ignition timing determining bag WECU including the electronic control unit 3, and the step motor 4 is connected to the engine ignition timing determining bag WECU including the electronic control unit 3. A slip joint mechanism 8 is attached to the manually operated throttle lever 9, which can be controlled arbitrarily.
The throttle lever 9 is connected to the throttle lever 9 by a universal joint 10, and is provided with a potentimeter as a valve opening sensor 1) for sensing the opening. Electronic control unit 3
are the valve opening detection switch 7 and the valve opening sensor 1).
and is electrically connected to the engine rotation sensor 12 and the engine stop circuit 13.

In this case, the electronic control unit 3 receives the rotation signal of the internal combustion engine, the signal of the valve opening of the carburetor l, and the signal of the predetermined valve opening from the valve opening detection switch 7, and calculates the predetermined rotation. The step motor 4 rotates the carburetor valve shaft 5 in the closing direction to perform speed regulating control.

Since the voltage Vref inputted to the D/A converter 14 via the data bus 17 is supplied with current controlled according to the required speed of the motor, efficiency is increased at each characteristic point of the step motor as shown in FIG. 5I. Good torque can be obtained, there is no current consumption corresponding to the extra torque, power loss is extremely low, and heat generation can be reduced. In addition, if the frequency of use in the high speed range is small, the feedback current can be increased to easily increase the speed. It also becomes possible. In any case, the feedback voltage V is set so that the optimum current for the required output can be supplied to each motor coil 41 according to the motor speed pulse calculated and set in advance to control the step motor 4.
It controls ref.

Note that a rotation sensor 12 used to detect the engine rotation speed
Alternatively, outputting an excitation pulse from a ring gear to a counter may be used.

Furthermore, it is preferable to use a stepping motor that rotates left and right by a constant angle using an output signal from a transistor. The opening detection switch 7 has a function of detecting the position origin of the step motor 4 and recognizing step-out, and drives the step motor 4 toward the valve opening side at startup, recognizes the 0 point at switch 08, and fully closes the throttle input. It is preferable to use a method that determines whether the signal is out of synchronization by checking whether it is ON or OFF.

C Effects of the Invention] The present invention detects the current flowing to the step motor coil with a feedback resistor, compares it with a reference voltage using a comparator, and controls the ON and OFF of the transistor to control the current flowing to the step motor coil. , the feedback voltage is controlled by a D/A converter and used as a reference voltage to the comparator so that the optimum current for the required output can be supplied to each step motor coil according to the motor speed pulse calculated and set in advance. At the start of output, a reference voltage corresponding to the required pulse speed of the step motor is outputted from the D/A converter, and then the motor drive pulses are output, making it easy to control the current according to the required motor speed, reducing power loss and increasing capacity. Since only a small transistor is required and there is little heat generation, it is possible to make the heat sink more compact, and it is also possible to create a step motor drive circuit that can easily increase the speed of the step motor, and the supply current for the motor drive can be adjusted to the optimum supply current for the required load. This provides the effect of ensuring stable operation of the carburetor through control, and also enables highly reliable control with reasonable operability of the carburetor.

[Brief explanation of drawings]

Fig. 1 is an electric circuit, Fig. 2 is a system explanatory diagram, Fig. 3 is an electric circuit diagram of a conventional example, Fig. 4 is a system explanatory diagram of a conventional example, and Figs. 5 (I) and (U) are motor torque diagrams. 1 is a characteristic diagram of motor speed showing the relationship between generated torque and load; (1) shows an example of the present invention, and (II) shows a conventional example. 1... Carburetor, 2... Throttle valve, 3... Electronic control unit, 4... Step motor, 41
...Step motor coil, 5...Valve shaft, 5.・・・
・Motor output shaft, 6, 10... Universal joint, 7... Valve opening detection switch, 8... Slip joint mechanism, 9...
・Throttle lever, 1)...Valve opening sensor, 12・
... Engine rotation sensor, 13 ... Engine stop circuit, 1
4...D/A converter, 15...Comparator,
16...Transistor, 17...Data bus. Patent Applicant Nissan Koki Co., Ltd. Representative Patent Attorney Minoru Yakushi Representative Patent Attorney Yori 1) Takatsugu Department Representative Patent Attorney Takashi
Masayuki KiFigure 1Figure 3Figure 5

Claims (3)

[Claims] (1) When controlling the throttle valve of the carburetor with a drive step motor, after initial setting by the step motor, engine rotation and throttle angle data are electronically controlled using a rotation sensor and a throttle valve opening sensor. The input is input to the unit and the ignition is controlled accordingly, and the current flowing to the step motor coil is detected by a feedback resistor, compared with a reference voltage by a comparator, and the transistor is ON-OFF controlled to control the current flowing to the step motor coil. , the reference voltage to the comparator is controlled by controlling the feedback voltage with a D/A converter so that the optimum current for the required output can be supplied to each step motor coil according to the motor speed pulse calculated and set in advance. An automatic control method for a vaporizer, characterized in that: (2) The step motor drive signal is such that at the start of control output, a reference voltage Vref corresponding to a required pulse speed is output from a D/A converter and then a motor drive pulse is output. Automatic control method for vaporizer. (3) The step motor is connected to an engine ignition timing determining device ECU including an electronic control unit, and can be controlled arbitrarily according to the engine condition. The automatic control method for a vaporizer according to item 1 or 2.