JPS61244838A - Throttle-valve driving apparatus for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent the deterioration of control for the opening degree of a throttle valve due to the adhesion of carbon by moving a throttle valve in reciprocation at least in one time in the initial time in driving the throttle valve and removing the carbon adhering around the throttle valve and the driving shaft for the throttle valve. CONSTITUTION:A throttle valve 1 is fixed onto a driving shaft 2, which is axially supported in rotatable ways onto the bearing part 4 of a fuel feeding passage 3. The output shaft 6 of a stepping motor 5 is connected to one edge part of the driving shaft 2. A perfectly opened stopper 7 and a perfectly closed stopper 8 for regulating the revolution over a certain degree of the throttle valve 1 are arranged at the perfect opened position and the perfect closed position of the throttle valve 1. Therefore, at the initial time in driving the throttle valve 1, the stepping motor 5 is driven to move the throttle valve 1 in reciprocation at least in one time between the perfectly opened stopper 7 and the perfectly closed stopper 8. A prescribed purpose can be achieved by removing the carbon adhering onto the part between the throttle valve 1, driving shaft 2 for the throttle valve 1, and a bearing part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a throttle valve drive device for an internal combustion engine having a throttle valve in its intake system.

(Prior Art) A throttle valve is provided in the intake system of an internal combustion engine, and this throttle valve is an extremely important element as a means for adjusting the amount of fuel supplied to the combustion chamber, and requires highly accurate driving.

By the way, this throttle valve is located near the combustion chamber, so due to the rapid combustion of the mixed gas.

Exhaust gas may blow back from the intake boat into the intake system. In addition, in an internal combustion engine equipped with an exhaust gas recirculation system (EGR), a part of the exhaust gas is taken out from the exhaust system and recirculated to the intake system in order to reduce NOx in the exhaust gas. There are some that return the mixed gas of fuel and fuel to the combustion chamber via a throttle valve and combust it.

(Problem to be solved) By the way, when exhaust gas is blown back from the intake boat in this way, and when a part of the exhaust gas is recirculated to the intake system in an internal combustion engine using an EGR system, the throttle Since the valve is constantly exposed to exhaust gas components, carbonized components (carbon) adhere to the drive shaft of the throttle valve. This carbon deposition obstructs the opening and closing operations of the throttle valve, making it difficult to control the opening using a highly accurate actuator. This problem is especially serious in electronically controlled throttle valves, which are now available.

(Means for solving problems) This invention was made in view of these circumstances.

The internal combustion engine is equipped with a throttle valve for controlling the amount of fuel supplied to the intake system, and is characterized in that the throttle valve is reciprocated at least once at the initial stage of driving the throttle valve.

(Function) In this invention, the throttle valve is specially caused to reciprocate at the initial stage of driving the throttle valve. As a result, carbon adhering to the throttle valve and around its drive shaft is shaken off, and deterioration of opening control of the throttle valve due to adhesion of carbon can be prevented.

(Example) Hereinafter, an example in which the present invention is applied to an EGR system will be described in detail based on the accompanying drawings.

First, the principle of this invention will be explained. 1 and 2 show a throttle valve which is the main part of the present invention, and FIG. 3 shows an aspect of the throttle valve according to the present invention based on changes in operation over time.

As shown in FIGS. 1 and 2, the throttle valve l is fixed to a drive shaft 2, and this drive shaft 2 is rotatably supported by a bearing 4 of a fuel supply passage 3. As shown in FIGS. One end of the drive shaft 2 is connected to an output shaft 6 of an actuator, for example, a stepping motor 5.

This throttle valve 1 takes out a part of the exhaust gas from the exhaust system,
EGR recirculates the mixture of exhaust gas and fuel to the intake system and returns it to the combustion chamber of the internal combustion engine for combustion.
Used to control the gas mixture in the system. Opening/closing control of the throttle valve 1 is performed by a stepping motor 4, and the opening control range is the fully open position (horizontal two-dot chain line position).
to the fully closed position (shaded position with two-dot chain line), and is normally set at about 70°.

A fully open stopper 7 and a fully closed stopper 8 are arranged at the fully open position and the fully closed position to restrict and prevent further rotation of the throttle valve l. At this time, in order to always accurately contact and regulate the position of the throttle valve l in the fully open position or the fully closed position, the control signal supporting the rotation range of the throttle valve l is
When the stepping motor 5 is used as the actuator, the position regulated by the fully open stopper 7 and the fully closed stopper 8 is set as the reference position for controlling the opening of the throttle valve 1. , opening angle θ
is changed by the stepping motor rotation angle Δθ, as shown in equation (1) below.

θ = Δθ·n (1) Here, n is a signal (number of steps) given to the stepping motor 5 from the reference position to instruct sequential rotation.

In the throttle valve drive system configured as shown in FIGS. 1 and 2, the opening degree of the throttle valve is controlled in the manner shown in FIG.

The throttle valve 1 located at an arbitrary position at power 08:00 Tl is first operated in the fully closed direction and brought into contact with the fully closed stopper 8, and a predetermined time has elapsed from this contact time point T2 at a time point T3. , the rotation in the opposite direction to the full-open direction is started, and the full-open stopper 7 is brought into contact with the full-open stopper 7 at the full-open position (time point T4
), and then, at time point T5, the throttle valve l is again rotated in the fully closed direction and brought into contact with the fully closed stopper 8 (time point T6).
Then, the fully closed position is regulated until time point T7, and that position is set as the initial (reference) position, and the throttle valve is adjusted to the deviation angle θ from the fully closed angle as the standard for subsequent normal opening angle control. Control 1. That is, the throttle valve l reciprocates between the fully closed stopper 8 and the fully open stopper 7 at least once. This removes the carbon that has adhered to the throttle valve l itself and between the drive shaft 2 and bearing part 4 of the throttle valve 1. Furthermore, by bringing the throttle valve l into contact with the fully open position, you can check the operation of the actuator and open the throttle valve. You can check whether it is fully closed or fully open.

FIG. 3 shows an example of application of this invention to GHP (GAS).
This is the configuration of the main parts of the ENGINE HEAT PUMP) system.

A GHP system normally uses city gas as engine fuel to operate a heat pump, for example, to supply hot water or provide air conditioning.

In the figure, reference numeral 9 denotes a fuel valve, and this fuel valve 9 is opened and closed under the control of an engine control unit 1O, thereby adjusting the amount of fuel (city gas) supplied to the engine 11 side. The city gas that has passed through the fuel valve 9 is transferred to the mixer 12
The mixture is mixed with air and exhaust gas components of EGR (exhaust gas relubrication device), and then passed through the intake passage 13 to the engine 11.
The fuel is sent to the combustion chamber 4. The mixed gas is burned in the combustion chamber 14, and the exhaust gas is passed from the exhaust passage 15 to the exhaust muffler 1.
6. A portion of this exhaust gas is taken out from the exhaust system, controlled in terms of temperature, flow rate, etc., recirculated to the intake system, and returned to the mixer 12.
3 is opened and closed by an intake valve 17, and the exhaust passage 15 is opened and closed by an exhaust valve 18.

The amount of the mixed gas is controlled by the throttle valve l, and the amount of the mixed gas is controlled by the throttle valve l.
1. The opening degree of this throttle valve l is controlled to maintain the rotational speed of the engine 11 constant. In other words, fluctuations in engine speed due to load fluctuations, disturbances in intake air volume, etc. are detected by the detection signal from the crank rotation sensor 19 on the signal line 2.
Detected via 0. Based on this detection signal, the engine control unit 10 controls the stepping motor 5 as a driving means (actuator) for the throttle valve l. The engine control unit IO controls the output of the cooling water temperature sensor 21 from the engine 11 and the oil level sensor 22 in addition to controlling the engine speed to maintain a constant engine speed.
The ignition coil 2 (for example, an engine control unit) 10 receives the output of the engine and controls various engine systems.
3 to send an optimum ignition timing signal to the spark plug 24.

FIG. 5 and FIG. 6 show the engine control unit 10.
FIG. 2 is a configuration diagram of a stepping motor 5. FIG.

The engine control unit TO receives direct current m+t2v as an input power source, and includes a power supply circuit 101 that outputs +5cm direct current power for operating a CPU (for example, a 1-chip 8-bit microcomputer), and a crank rotation sensor 19 (for detecting the engine speed). Engine pulse input circuit 1 which receives the output from the engine pulse piper (2 pump coils) and supplies a rotation speed signal indicating the engine rotation speed to the CPU 102
03, and a sensor input circuit 104 that receives various status output signals such as the output of the cooling water temperature sensor 21 and the output of the engine oil level sensor 22 indicating the engine engine temperature, and inputs them to the CPU 102.

The CPU 102 operates rapidly in response to a clock signal of a predetermined frequency from the oscillation circuit 105. The CPU 102 sets the current engine rotation speed N to a predetermined reference rotation speed Nre.
When a difference occurs between the two rotational speeds, the stepping motor 5 is controlled to rotate via the stepping motor drive circuit IQ6 in order to make the difference zero. Taking an example in which the stepping motor 5 is a four-phase motor and has four excitation windings, the stepping motor drive circuit 106 sequentially receives a pulse sequence in the form of A pulse is sent out.

In FIG. 6, a timing chart of signals supplied to each terminal 51 to 54 in order to rotate the stepping motor 5 at a constant speed is shown in chronological order in response to the clock from the oscillation circuit 105.

In Figure 6, the numbers 1 to 9 at the top represent the number of clocks C
n), and a pulse sequence is determined for each numerical state. In order to determine the absolute position of the stepping motor 5, which is the relative position change control means, a stopper is provided corresponding to the fully open position and the fully open position of the throttle valve 1, so that the stepping motor 5 when the throttle valve 1 is fully closed and fully open is provided. The state of is set as the initial state, the pulse sequence in this initial state is set as the initial value of the angle, and thereafter the opening angle of the throttle valve I is controlled from this initial value.6 For example, after the fully closed position is detected. , set the opening degree to O° with that position as the initial position, and
Set the clock number i to 0 to create the pulse sequence in chronological order, then check the front closed position with the fully open stopper, perform initial confirmation of the operation, and then control the engine speed N to be constant. Start. That is, the control signal is determined based on the current engine speed N and a predetermined reference speed Nref. This control signal Vref is usually
It is determined by the following formula based on so-called PID control.

Vref=P+I+D+offset Here, P is a proportional term, [Nref-N] number KpI
is an integral term, [Σ(Nref-N)]・Ki D is a differential term, [N-N (pgs t)]・Kd (Kd, Ki, Kd are coefficients) The control signals obtained in this way correspond to The signal is supplied to the stepping motor drive circuit 106 to adjust the opening angle of the throttle valve l.

(Effects of the Invention) As explained above, in this invention, when the throttle valve is driven, the throttle valve is reciprocated at least once to remove carbon. This will prevent it from becoming a hindrance. Therefore, the opening degree can be smoothly controlled by a particularly highly accurate actuator, and is particularly suitable for the operation of throttle valves that are recently electronically controlled.

[Brief explanation of drawings]

1 and 2 are schematic configuration diagrams of a throttle valve showing an embodiment of the present invention, FIG. 3 is a diagram showing the operating principle of the throttle valve, and FIG. 4 is a diagram showing the operating principle of the throttle valve.
5 is a block diagram of the main parts of a GHP system showing an application example of the present invention, FIG. 5 is a block diagram of the engine control and stepping motor shown in FIG. 3, and FIG. 6 is a timing chart of operation signals of the stepping motor. l... Throttle valve 2... Drive shaft 3... Fuel supply passage 4... Bearing portion 5... Stepping motor 6... Output shaft 7... Fully open stopper 8.
...Fully closed stopper lO...Engine control unit Fig. 1
Figure 2 Figure 3 □ Daily schedule A') Figure 6 Human Power Pond) 54

Claims (1)

[Claims] A valve drive device for an internal combustion engine, which is equipped with a throttle valve for controlling the amount of fuel supplied to an intake system, wherein the throttle valve is reciprocated at least once at an initial stage of driving the throttle valve.