JPS606012A - Suction/exhaust valve controller for internal- combustion engine - Google Patents

Abstract

PURPOSE:To achieve electronic control of suction/exhaust valve by employing means for detecting the absolute angle of cam shaft and detecting the piston position even under stoppage or starting of engine. CONSTITUTION:A signal indicating the current cam shaft angle is fed from an encoder 1 to I/O port 24 of microcomputor in the form of binary code. The absolute cam shaft angle is calculated against the referential position where the output from the encoder 1 will be 0 and stored in RAM22. The output from the encoder 1 is inputted to comparators 27a, b to operate the engine speed in CPU 21. The optimal valve open/close timing corresponding to the engne condition is inquired to ROM23 to control the solenoid valves 3, 4 in the hydraulic system for driving the suction and exhaust valves thus to drive the suction/exhaust valve under the optimal condition corresponding to the engine condition. Since the absolute cam shaft angle is detected, it can be controlled even under stoppage or immediately after starting.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake/exhaust valve control device for an internal combustion engine that electronically controls the opening/closing timing of the intake/exhaust valves, fuel injection timing, etc. When electronically controlling the engine according to the operating status of the engine, it is necessary to detect the piston position. Conventionally, it is necessary to detect the piston position by detecting the position of the piston. It is generally known that the piston position can be determined by counting the signals from the mark on the crankshaft after the signal from the mark on the camshaft is received by using the signal when a certain mark passes. .

According to this method, the piston position can be detected without any problem while the engine is rotating, but the piston position cannot be detected while the engine is stopped or immediately after starting until the signal from the mark on the camshaft is received. First, in the case of 4-cycle ia, control is impossible until the crankshaft rotates a maximum of two revolutions. Therefore, in the past, the above-mentioned problems were avoided by taking measures such as not using electronic control for starting, but starting electronic control after starting, and using electronic control functions to adjust the opening and closing timing of intake and exhaust valves appropriately. However, no effort had been made to improve the startability of the engine.

The present invention has been made in view of the above-mentioned problems, and aims to provide an intake/exhaust valve control device that can perform electronic control board functions even when the engine is stopped or immediately after starting. In internal combustion engines that electronically control the opening and closing timing of intake and exhaust valves according to the engine operating status, camshaft absolute angle detection is used to detect the rotation angle of the camshaft with respect to a certain camshaft position as a reference position. means, an engine rotation speed detection means for detecting the engine rotation speed, and a piston position 'G3Me' detected from the detected camshaft angle, and a predetermined engine rotation speed detection means, which detects the piston position from the detected engine rotation speed, The present invention is characterized by comprising calculation means for calculating the opening timing and closing timing of the intake valve and the opening timing and closing timing of the exhaust valve in the operating range, and outputting a control output for the six valves.

That is, the present invention makes use of the fact that the camshaft rotates at a speed of 172 degrees of the crankshaft in a four-cycle engine, while maintaining a constant relationship with the crankshaft, and calculates the angle of the camshaft based on the absolute angle of the camshaft with respect to a certain reference position. The piston position can be recognized even when the engine is stopped or immediately after starting, and it becomes possible to properly control the intake and exhaust valves from the beginning of the engine starting operation.

Hereinafter, the present invention will be specifically explained with reference to illustrations and legends. In this embodiment, a special engine rotation speed detection means is not used, and the camshaft absolute angle detection means is utilized to detect the root circumference rotation speed.

@1 diagram is the shelf, smoked Z system ratio 1, and in the diagram, (1)
I″i is an absolute type rotary encoder used as a camshaft absolute angle detection means, (2) is a microcomputer used as a calculation means, +: nh exhaust valve solenoid, (4) is an intake valve solenoid 0 encoder (1) is directly connected to a camshaft (not shown) that rotates at 1/2 the engine rotational speed, and the current angle of the camshaft with respect to a certain reference position is detected, and the detection result is expressed in the form of a binary code. ○ The microcomputer (2) is configured to have a CPU (2]), a sink ((2, ROM 1%), an I10 boat (1), a Kakunta company, an oscillator (a), The encoder (1) is equipped with a first comparator (27a), a second comparator (27b), etc., and these are connected to each other through a bus. ) The knot is nine.

The solenoid (:1)+4) is for operating the hydraulic exhaust valve and intake valve (none of which are shown), and the transistors (3I) and (41) are turned on and off by the output of the above-mentioned I10 port +24). ) are connected in series.

First, to explain the camshaft angle detection button, the encoder (1) sends a binary signal indicating the current camshaft angle.
It is sent in the form of a code to the I10 port of the microcomputer (2). If the numerical value indicated by this detection signal is A, and the resolution of the encoder (1) is B, then the current camshaft angle is the position where the numerical value of the encoder (1) output becomes 0,
In other words, it can be calculated by calculating 720 x A/13 points with respect to the reference position, and the result of this calculation is stored in the memory as appropriate.

Next, detection of engine rotation speed will be explained.

First, from the CPU (2 (transition)) to the comparator (27a)
Similarly, a certain force is applied to the comparator (27b) at 72
0 × θ2 is given, t and i each comparator (27a)
The output of encoder (1) is input to (27b). When the camshaft angle reaches θIK due to engine rotation, the signal input from the encoder (1) corresponds to the value given to the comparator (27a). )
A signal is sent to the first interrupt terminal (21a) of the CPU (21), and the counting of the number of pulses output from the oscilloscope (2) is started.

Subsequently, when the camshaft angle reaches 02, the signal from the encoder (1) causes the K signal to be sent from the converter and the parator (27b) to the stop terminal (25b) of the kakuntai (to), and the kakuto operation at the kakunta (to) stops. will be stopped. At the same time, the ``I'' signal of the comparator (27b) is also input to the second interrupt terminal (21b) of the CPU υ, and the CPU (21) outputs θ
The number N of pulses counted during the angle of 2-θ1 is input from the counter (b), and the rotational speed n at that time is calculated.

The rotational speed n at this time is given by the following equation.

When no signal is received from either of the comparators (27a) and (27b), or when only one signal is received, it is determined that the ramming is stopped, and n =
0 is given.

Next, according to the flowcharts shown in Figures 2 to 4,
The opening/closing timing control of the intake and exhaust valves will be explained.

FIG. 2 relates to the setting of the initial opening/closing timing, which is performed prior to starting the engine. First the control device is switched on, in step 1 the encoder (1)
The value of the camshaft angle X is input from . Next, in step 2, it is determined whether the camshaft angle X is at a position between the initial exhaust valve opening timing x0 and the initial exhaust valve closing timing The valve closing timing x1 is input to the comparator (27a), and when there is no time, α=0 and the valve opening timing X0 is input to the comparator (27a). Follow the same procedure to determine the camshaft angle X and initial intake valve opening timing Y for the intake valve. , the initial intake valve closing timing Y0 is compared in step 3, and the camshaft angle X is Y. When it is between and Qi, set β=1 and use comparator
Input the valve closing timing Y into the comparator (27b), and input the valve opening timing Y into the comparator (27b) with β=0 if there is no time. The initial setting when n=o is performed as described above.

FIGS. 3 and 4 respectively relate to control of the optimum opening/closing timing of the exhaust valve and intake valve when the engine is rotating. This control is performed by interrupting the bottom end of the 70-chart shown in FIG. ing.

The optimum opening/closing timing of the intake air valve varies depending on the engine speed, so the initial opening/closing timing X0, X engineering, Y
In addition to o, Yl, etc., the optimum intake valve opening timing, optimum exhaust valve closing timing X1, optimum intake valve opening synchronization Yo, and optimum intake valve closing timing Y1 at each rotation speed are plotted, for example, in a graph R.
OM (Z'l) Introverted memorization.

Regarding Figs. 3 and 4, we will first explain the valve opening WiJ. The optimum intake valve opening timing corresponding to the engine rotational speed at that time is selected from the ROM (iln) and given to the comparator (27a). Select the optimum intake valve opening timing y0 from the ROM (ROM), and set the Kumperator (27b) K.
(steps 4 and 4'). When the output of the encoder (1) matches the value given to the comparator (27a),
:ff n/< V-ta (27a) to CPU (21
), a signal enters the interrupt terminal (21a) of the CPU (21
) outputs a signal to turn on the transistor (3I) to energize the exhaust valve solenoid (3) (step 5), and the ROM' (23) selects the optimal exhaust valve closing timing x1 as the comparator ( 27a) (step 6). Also, when the output of the encoder (1) matches the value given to the comparator (27b), the output from the comparator (27b) is sent to the interrupt terminal (21b) of the CPU (21).
), a signal is input from the CPU 1) to turn on the transistor 1) to excite the intake valve solenoid (4) (step 5'), and a signal is output from the ROM 1).
The optimal intake valve closing timing yl selected from
The value of the PU transmission counter (b) is input, the engine rotational speed is calculated according to the procedure described above, and the authorized rotational speed n is updated (step 8).

Similarly, when the closing timing of the six valves is reached, a signal is output from each comparator (27a) and (27b), and the CPU
A signal is output to turn off the transistors (31) GLI from 20, each solenoid (3H4) is de-energized, and the six valves are closed (steps 7 and 7'). At the same time, the valve opening timing equation and yo are given to each comparator (27a) (27b), and the procedure from steps 4 and 4' described above is repeated.

In this way, in this embodiment, from the absolute '-type rotary encoder f1+ to fj'-, t
The detection signal of the camshaft angle is rounded both when the camshaft is rotating and when the camshaft is rotating, and the opening and closing timing of the exhaust valve is controlled according to the rotational speed of each shaft. This makes it possible to properly control the opening and closing of the valve even in the early stages of startup, when operation is unstable. In addition, the opening and closing timing of the intake and exhaust valves is as follows.
It is also possible to perform a correction calculation according to the rotation speed between piles based on the initial value, and it can be determined by a comprehensive correction calculation that includes not only the rotation speed between piles but also corrections based on other factors. It can also be treated.

As is clear from the above embodiments, according to the present invention,
It has the advantage that the piston position can be detected even during a gradual opening stop or immediately after starting, and the built-in electronic control #l1 function can be effectively used to appropriately control the opening and closing timing of the intake and exhaust valves. There is no need to provide a sensor on both the shaft and the crankshaft, and it is only necessary to provide a sensor on the camshaft, which simplifies the structure and reduces costs.

[Brief explanation of the drawing]

FIG. 1 is a conceptual system diagram of an embodiment of the present invention, and FIGS. 2 to 4 are control flowcharts. (1)...Absolute type rotary encoder,
(2)...Microcomputer, (3)...Exhaust valve solenoid, (4)...Intake valve solenoid, t
2])...CPU, (transfer))...ROM, (
25j - Kakunta, (27a) (27b) -
Con/Crake O Special]: Applicant Yanmar Diesel Co., Ltd. Agent
Patent Attorney Shino 1) True! #1 Figure 3 Figure 4 Figure 69-

Claims (1)

[Claims] fl) In an internal combustion engine in which the opening/closing timing of intake and exhaust valves is electronically controlled according to the operating state of the engine, the rotation angle of the camshaft with respect to a certain camshaft position is detected as a reference position. camshaft absolute angle detection means for detecting the engine rotational speed; and engine rotational speed detection means for detecting the engine rotational speed.The piston position is recognized from the detected camshaft angle, and the stopped state of the V&amp; intake valve opening timing and valve closing timing in a predetermined operating range including
An intake/exhaust valve control device for an internal combustion engine, comprising: a calculation means for calculating the opening timing and closing timing of the exhaust valve and outputting a control output for the six valves.