JP2008267145A - 4-stroke diesel engine control device and cam pulse signal generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a diesel engine only by a pulse signal generated with rotation of a crankshaft without using a cam.
A rotation detection sensor 40a outputs one pulse signal each time a crankshaft 8 rotates by a predetermined rotation angle. Each time the crankshaft 8 makes one rotation, one rotation detection sensor 42a outputs one pulse signal. Sensors 40 a and 40 b are connected to the cylinder controller 14. The controller resets the count of the pulse signal of the sensor 40a when the pulse signal of the sensor 42a is input for the first time after the engine is started, and when the pulse signal of the next sensor 42a is input, the controller When the pulse signal of the sensor 42a is input next, the count of the pulse signal of the sensor 40a is reset. The controller 14 counts the pulse signal of the sensor 40a over two revolutions of the crankshaft 8, and controls the fuel injection valve 10, the intake valve 26, and the exhaust valve 24 based on the pulse signal of the sensor 40a.
[Selection] Figure 1

Description

  The present invention relates to control of a four-stroke diesel engine, and more particularly to generation of a cam pulse signal generated with rotation of a crankshaft in order to control a fuel injection valve, an intake valve, and an exhaust valve.

  Generally, in a 4-stroke diesel engine, as shown in FIG. 2 of Patent Document 1, a cam for driving an intake valve and an exhaust valve is rotated once every two crankshafts of the diesel engine. Driven by. A technique for driving an intake valve and an exhaust valve with an electromagnetic valve or a hydraulic cylinder without using this cam is shown in FIG.

JP-A-8-170551

  According to the technique of Patent Document 1, cams for driving the intake valve and the exhaust valve can be omitted. However, in a 4-stroke diesel engine, the strokes of compression, explosion, exhaust, and intake are performed while the crankshaft rotates twice. It is not possible to determine which of the strokes or the stroke of explosion or intake.

  The present invention relates to a control device for a four-stroke diesel engine that can be controlled only by a pulse signal generated with the rotation of the crankshaft, and generates a virtual cam pulse signal based on the pulse signal generated with the rotation of the crankshaft. An object of the present invention is to provide a cam pulse signal generation method.

  In the control device according to one aspect of the present invention, each time the crankshaft of the four-stroke diesel engine rotates by a predetermined rotation angle, for example, an angle smaller than the angle at which the crankshaft rotates once, one pulse signal is sent to the first rotation sensor. Is output. Each time the crankshaft makes one revolution, the second rotation sensor outputs one pulse signal. First and second rotation sensors are connected to the controller, and the controller calculates a fuel injection timing, an intake valve opening / closing timing, and an exhaust valve opening / closing timing of the 4-stroke diesel engine. Fuel injection means, intake valve opening / closing means, and exhaust valve opening / closing means are connected to the controller. The starting means rotates the crankshaft when starting the diesel engine. The controller resets the count of the pulse signal of the first rotation sensor when the pulse signal of the second rotation sensor is input at the start. The controller continues counting the pulse signal of the first rotation sensor when the pulse signal of the second rotation sensor is input next, and the first rotation sensor when the pulse signal of the second rotation sensor is input next. Reset the pulse signal count. That is, the pulse signal of the first rotation sensor is counted while the crankshaft rotates twice. The controller controls the fuel injection means, the intake valve opening / closing means, and the exhaust valve opening / closing means based on a pulse signal of the first rotation sensor, for example, a count value of the pulse signal.

  In the control device configured as described above, the pulse of the first rotation sensor is performed during two revolutions of the crankshaft, that is, from the start of the compression, explosion, exhaust and intake strokes of the four-stroke diesel engine until the end. Since the signal is counted, the rotation state of the crankshaft can be known without using a cam, and the fuel injection means, the intake valve opening / closing means and the exhaust valve opening / closing means are controlled based on this. Can do. In addition, a pump rotation shaft such as a drive source of an oil supply device connected to the crankshaft, a drive source of an intake valve, or an exhaust valve is operated so as to rotate once by a half rotation of the crankshaft. The cam pulse signal generating mechanism for outputting the cam pulse signal from the above can be omitted.

  When the pulse signal of the second rotation sensor is input at the start, the controller sets the virtual cam pulse signal to the first state, for example, the level is H level, and then the pulse signal of the second rotation sensor is input next. For example, when the crankshaft rotates 1/2 times from when the virtual cam pulse signal is in the first state, the virtual cam pulse signal is set to the second state, for example, L level. Each time one rotation of the shaft is detected, for example, every time the count value of the pulse signal of the first rotation sensor becomes a value corresponding to one rotation of the crankshaft, the state of the virtual cam pulse signal is changed between the first and second states. Of these, it can be changed to a state different from the current state, for example, to the L level if the current state is the H level, and to the H level if the current state is the L level. When the virtual cam pulse signal is in the second state, the controller continues counting the pulse signal of the first rotation sensor even if the pulse signal of the second rotation sensor is input.

  With this configuration, for example, every time the crankshaft makes one rotation, the state of the virtual cam pulse signal can be changed from the first state to the second state or from the second state to the first state. Therefore, by checking the state of the virtual cam pulse signal, it is possible to grasp whether the stroke is compression / exhaust or explosion / intake. In addition, even if the pulse signals of the first and second rotation sensors are not detected several times, the timing of compression / exhaust or explosion / intake does not change.

  The cam pulse signal generation method according to one aspect of the present invention is used for engine control together with the pulse signal of the first rotation sensor that outputs one pulse signal each time the crankshaft of a four-stroke diesel engine rotates by a predetermined rotation angle. A cam pulse signal is generated. When the pulse signal output from the second rotation sensor for each rotation of the crankshaft is generated for the first time after the diesel engine is started, the cam pulse signal is set to a first state, for example, its level is set to H level, and then Before the two-rotation sensor outputs a pulse signal, for example, when the crankshaft makes a half rotation, the cam pulse signal is set to the second state, for example, its level is set to the L state. Each time one rotation of the shaft is detected, the state of the cam pulse signal is changed to a state different from the current state among the first and second states. For example, if the current state is L level, it is changed to H level, and if the current state is H level, it is changed to L level.

  As described above, according to the present invention, it is possible to control a four-stroke diesel engine only with a pulse signal generated with the rotation of the crankshaft without using a cam.

  A four-stroke diesel engine in which the control device of one embodiment of the present invention is implemented has a cylinder 2 as shown in FIG. In FIG. 1, only one cylinder 2 is shown, but actually, a plurality of cylinders 2 are provided. A piston 4 is provided in the cylinder 2, and the piston 4 is coupled to a crankshaft 8 via a connecting rod 6.

  Fuel injection means, for example, a fuel injection valve 10 is provided in a chamber 9 on the opposite side of the connecting rod 6 across the piston 4 in the cylinder 2. The fuel injection valve 10 is supplied with fuel from a fuel pump 12, and the fuel pump 12 is controlled by a servo valve 16 in accordance with an instruction from a controller, for example, a cylinder controller 14.

  In this chamber 9, starting means, for example, a starting valve 18 is provided. The start valve 18 is controlled by the electromagnetic valve 20 in accordance with an instruction from the cylinder controller 14, and supplies start air into the room 9 at the start.

  Further, an intake valve 24 and an exhaust valve 26 are provided in the room 9. The intake valve 24 is opened / closed by an intake valve opening / closing means, for example, a servo valve 28, and the exhaust valve 26 is opened / closed by an exhaust valve opening / closing means, for example, a servo valve 30. The servo valves 28 and 30 are controlled by the cylinder controller 14.

  Lubricating valves 30 and 32 are also provided in the chamber 9, and these are controlled by electromagnetic valves 34 and 36 controlled by the cylinder controller 14, and lubricate between the piston rings of the piston 4.

  The servo valves 16, 28, 30 and the electromagnetic valves 20, 34, 36 are controlled by the cylinder controller 14. In order to perform this control, the cylinder controller 14 includes a plurality of first rotation sensors that detect rotations of the flywheel 38 attached to the crankshaft 8 at predetermined angles, for example, pulses of rotation detection proximity switches 40a to 40c. A signal and a plurality of second rotation sensors for detecting one rotation of the flywheel 38, for example, detection signals from one rotation detection proximity switches 42a and 42b are supplied.

  The rotation detection proximity switches 40a to 40c detect teeth provided at predetermined angles on the flywheel 38 and generate pulse signals. The pulse signals generated by the rotation detection proximity switches 40a, 40b, and 40c are arranged so that the phases differ by a predetermined amount. By making the phases different, the rotation direction can be detected based on the phase difference between two pulse signals among the pulse signals of the rotation detection proximity switches 40a, 40b, and 40c. Actually, although the rotation direction and the rotation angle can be detected by the two rotation detection proximity switches, since the three rotation detection proximity switches 40a to 40c are provided, any one of the proximity switches 40a to 40c fails. Or even if a disconnection occurs.

  The one-rotation detection proximity switches 42a and 42b detect one dog provided on the flywheel 38 and generate a pulse signal. The dog is arranged so as to be detected by the one-turn detection proximity switches 42a and 42b, for example, when the piston 4 reaches the top dead center. The one-rotation detection proximity switches 42a and 42b are arranged so that the phases of the pulse signals generated by these switches are different. As a result, it is possible to detect that one of the one-rotation detection proximity switches 42a and 42b has failed or disconnected. Further, the one-rotation detection proximity switch 42b is generated so that the pulse signal generated by the one-rotation detection proximity switch 42a is generated between two pulse signals generated successively by the rotation-detection proximity switch 40a. The dog is provided so that the pulse signal to be generated is generated between two pulse signals generated successively by the rotation detection proximity switch 40b.

  The cylinder controller 14 normally outputs a virtual cam pulse signal that can distinguish the stroke of the four strokes of the cylinder 2 using the signals of the rotation detection proximity switches 40a and 40b and the signal of the one rotation detection proximity switch 42a. And the direction of rotation of the crankshaft 8 is detected.

  The rotation direction is determined by the cylinder controller 14 based on, for example, pulse signals from the rotation detection proximity switches 40a and 40b. For example, when the pulse signal of the rotation detection proximity switch 40a shown in FIG. 2 (a) is at the H level and the pulse signal of the rotation detection proximity switch 40b shown in FIG. 2 (b) rises to the H level, the cylinder controller 14 is determined to be normal rotation, and the direction signal is set to the H level as shown in FIG. If the pulse signal of the rotation detection proximity switch 40a rises to H level when the pulse signal of the rotation detection proximity switch 40b is H level, the cylinder controller determines that the rotation is reverse and sets the direction signal to L level. .

  The cylinder controller 14 includes a counter that counts the pulse signal of the rotation detection proximity switch 40a. This counter is reset when the proximity switch 42a for one rotation detection generates a pulse signal for the first time after the cylinder 2 starts operation. This counter counts at the up and down edges of the pulse signal of the rotation detection proximity switch 40a, and increases the count value in the case of normal rotation and decreases the count value in the case of reverse rotation. The cylinder controller 14 has a virtual cam pulse signal generation circuit in addition to the counter. The virtual cam pulse signal generation circuit has a first output level as shown on the left side of FIG. State, for example, H level. The count value of the counter is supplied to the virtual cam signal generation circuit. Two reference values are set in the virtual cam pulse signal generation circuit. The first reference value is, for example, a value corresponding to the count value when the flywheel 38 rotates 1/2 forward after the generation of the pulse signal of the one-rotation detection proximity switch 40a. The virtual cam pulse generation circuit compares the count value of the counter with the first reference value, and when the count value reaches the first reference value, as shown at time t1 in FIG. The signal is changed to a second state, for example, L level. The second reference value is a value corresponding to the count value when the flywheel 38 rotates 3/2 forward after the generation of the pulse signal of the one-rotation detection proximity switch 40a, and the time of FIG. When the count value of the counter reaches the second reference value as indicated by t2, the virtual cam pulse signal is changed from the L level to the H level. The counter is reset when the virtual cam pulse signal is at the H level and the pulse signal of the one-rotation detection proximity switch 42a is at the H level, that is, when the crankshaft rotates twice forward. Thereafter, the same operation is repeated.

  The reverse operation is performed in the same manner. That is, when the operation of the cylinder 2 is started, the virtual cam pulse signal becomes H level and the direction signal becomes L level. The counter is reset by a pulse signal of the one-rotation detection sensor 42a that is first generated from the start of operation, and performs a subtraction count every time the rotation detection sensor 40a generates a pulse signal. When the value coincides with a third reference value (this value is smaller by 1 than the second reference value) corresponding to the count value at the time of reverse rotation, the virtual cam signal changes to L level, and the subtraction count value becomes 3 / When it coincides with a fourth reference value (this value is 1 smaller than the first reference value) corresponding to the count value of 2 reverse rotation, the virtual cam pulse signal changes to the H level. When the one-rotation detection proximity switch 42a generates a pulse signal while the virtual cam pulse signal is at the H level, the counter is reset.

  In either case of forward rotation or reverse rotation, the period from when the pulse signal of the one-rotation detection proximity switch 40a is generated while the virtual cam pulse signal is at the H level until the virtual cam pulse signal becomes the L level, for example, in the intake stroke There is, for example, a compression stroke from when the virtual cam pulse signal becomes L level until the pulse signal of the one-rotation detection proximity switch 40a is generated, and the virtual signal is generated after the pulse signal of the one-rotation detection proximity switch 40a is generated. Until the cam pulse signal becomes H level, for example, is an explosion stroke, and from when the virtual cam pulse signal becomes H level until the pulse signal of the proximity switch for one rotation detection 40a is generated, for example, is an exhaust stroke.

  The count value of the counter changes according to each stroke, and the servo valves 16, 18, 30, and the electromagnetic valves 20, 34, 36 are controlled based on the virtual cam pulse signal and the count value of the counter.

  FIG. 3 (a) shows the pulse signal of the rotation detection proximity switch 40a when the cylinder 2 rotates in the reverse direction after 1/2 forward rotation, and FIG. 3 (b) shows the pulse signal of the rotation detection proximity switch 40b. The pulse signal of the proximity switch 42a for detecting one rotation is shown in FIG. 5C, the virtual cam pulse signal is shown in FIG. 4D, and the same direction signal is shown in FIG.

  The cylinder operates in the same manner as described above until the cylinder rotates 1/2 forward and the virtual cam pulse signal becomes L level. Then, when the cylinder rotates in reverse at t3, the cylinder controller determines reverse rotation from FIGS. 10A and 10B, and sets the direction signal to the L level as shown in FIG. At the same time, the counter performs a subtraction count. Since the count value when the subtraction count is started is a value that is 1 larger than the fourth reference value, which is the reference value at the time of 3/2 reverse rotation, when the subtraction count is performed, the count value is Immediately, it becomes equal to the fourth reference value, and the virtual cam pulse signal becomes H level as shown in FIG. In this state, the one-rotation detection proximity switch 42a generates the pulse signal shown in FIG. 5C, thereby resetting the counter. However, the virtual cam pulse signal remains at the H level. When the count value of the counter becomes equal to the third reference value, the virtual cam pulse signal becomes L level. Hereinafter, the same operation is performed.

  When the rotation detection proximity switch 40a fails or is disconnected, the cylinder controller 14 uses the pulse signal of the rotation detection proximity switch 40b according to an instruction from a failure detection circuit (not shown) to continue the control. At this time, there is a period in which the supply of the pulse signal to the counter is stopped, the change in the count value of the counter is delayed, and the generation timing of the virtual cam pulse signal is shifted, but based on the output of the one-turn detection proximity switch 42a This deviation is eliminated when the counter is reset.

  When the one-rotation detection proximity switch 42a fails or is disconnected, the cylinder controller 14 uses the pulse signal of the one-rotation detection proximity switch 42b according to an instruction from the failure detection circuit to continue the control. At this time, when the counter should be reset, the count value of the counter may be different from a predetermined value. For example, during normal forward rotation, the counter is reset after the count value reaches 240, and the count value should become 0 because of the failure or disconnection of the one-rotation detection proximity switch 42a. 243... In this case, when the count value becomes a value that is larger than the count value to be reset by a predetermined value, the cylinder controller 14 sets the count value of the counter to a predetermined value. For example, if the predetermined value is 4, when the count value of the counter reaches 244, the count value of the counter is set to 4. This has no effect on the generation of the virtual cam pulse signal. In the case of reverse rotation, when the counter becomes smaller than the count value to be reset by a predetermined value, the count value of the counter is set to a predetermined value.

  In the above embodiment, the proximity switch is used for detection of rotation of the crankshaft at a predetermined angle and detection of one rotation. However, the present invention is not limited to this, and for example, a photoelectric switch can also be used.

1 is a block diagram of a control device for a 4-stroke diesel engine according to an embodiment of the present invention. FIG. It is a wave form diagram of each part of the control apparatus of FIG. 1 when the diesel engine is rotating forward. It is a wave form diagram of each part of the control apparatus of Drawing 1 when a diesel engine reverses from normal rotation on the way.

Explanation of symbols

2 cylinder 8 crankshaft 40a to 40c rotation detection proximity switch (first rotation sensor)
42a, 42b 1 rotation detection proximity switch (second rotation sensor)
14 Cylinder controller (controller)
10 Fuel injection valve (fuel injection means)
24 exhaust valve 26 intake valve 28 servo valve (exhaust valve opening / closing means)
30 Servo valve (Intake valve opening / closing means)

Claims (3)

A first rotation sensor that outputs one pulse signal each time the crankshaft rotates by a predetermined rotation angle;
A second rotation sensor that outputs one pulse signal each time the crankshaft makes one rotation;
A controller that is connected to the first and second rotation sensors and calculates fuel injection timing, intake valve opening / closing timing, and exhaust valve opening / closing timing;
Fuel injection means connected to the controller;
Intake valve opening and closing means connected to the controller;
Exhaust valve opening / closing means connected to the controller,
In the control device of the four-stroke diesel engine provided,
The controller resets the pulse signal count of the first rotation sensor when the first pulse signal of the second rotation sensor is input after starting,
The controller continues counting the pulse signal of the first rotation sensor when the next pulse signal of the second rotation sensor is input,
The controller resets the count of the pulse signal of the first rotation sensor when the pulse signal of the second rotation sensor is input next,
The controller counts the pulse signal of the first rotation sensor over two rotations of the crankshaft, and based on the pulse signal of the first rotation sensor, the fuel injection means, the intake valve opening / closing means, and the exhaust valve opening / closing means 4 stroke diesel engine control device. The control device for a four-stroke diesel engine according to claim 1,
The controller sets the virtual cam pulse signal to the first state when the pulse signal of the second rotation sensor is input at the start, and then the virtual cam pulse signal before the pulse signal of the second rotation sensor is input next. Is changed to the second state, and thereafter, each time the first rotation sensor detects one rotation of the crankshaft, the state of the virtual cam pulse signal changes to a state different from the current state among the first and second states. Let
When the virtual cam pulse signal is in the second state, the controller continues to count the pulse signal of the first rotation sensor even if the pulse signal of the second rotation sensor is input. In a cam pulse signal generation method for generating a cam pulse signal used for controlling a four-stroke diesel engine together with a pulse signal of a first rotation sensor that outputs one pulse signal each time the crankshaft rotates by a predetermined rotation angle,
When the pulse signal output from the second rotation sensor for each rotation of the crankshaft is generated for the first time after starting the diesel engine, the cam pulse signal is set to the first state, and then the second rotation sensor Before outputting the pulse signal, the cam pulse signal is set to the second state, and thereafter, every time the first rotation sensor detects one rotation of the crankshaft, the state of the cam pulse signal is changed to the first and second states. Of generating a cam pulse signal that changes the current state to a state different from the current state.

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