JP2011038413A - Control method of internal combustion engine and internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent breaking of an internal combustion engine caused by a collision between suction-exhaust valves and a piston, in the internal combustion engine having a variable valve train capable of varying the opening-closing timing and a lift quantity of the suction-exhaust valves by hydraulic pressure. <P>SOLUTION: A diesel engine 1 includes variable valve train parts 15a and 15b capable of varying the opening-closing timing and the lift quantity of the suction-exhaust valves 11a and 11b by the hydraulic pressure, and controls so as to close the suction-exhaust valves 11a and 11b with every preset time without synchronizing with a crank angle in a synchronization fall of the crank angle. Thus, the collision between the valves 11a and 11b and the piston 3 can be prevented in the synchronization fall of the crank angle, and breaking of the diesel engine 1 caused by the collision can be prevented. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an internal combustion engine control method and an internal combustion engine. More specifically, the present invention relates to an intake / exhaust valve in an internal combustion engine having a variable valve mechanism that varies the opening / closing timing and lift amount of the intake / exhaust valve by hydraulic pressure. The present invention relates to an internal combustion engine control method and an internal combustion engine capable of preventing destruction of the internal combustion engine due to a collision between the piston and the piston.

  In recent years, combustion control has become more advanced with the increasing demand for exhaust gas regulations and fuel efficiency improvements for automobile engines. As one method for improving combustion control, variable valve timing technology (hereinafter referred to as VVT) that makes it possible to adjust the opening / closing timing and lift amount of the intake / exhaust valves according to the engine speed and load. (See, for example, Patent Document 1).

  The basic operation of this VVT technique is to set the closing timing of the intake valve to the retarded angle side from the bottom dead center of the piston, and to close the intake valve late (for example, refer to Patent Document 2). This slow closing control of the intake valve is forcibly performed by a mechanical mechanism once in one cycle (720 ° CA) of engine operation. In this control, in order to close the intake valve, the hydraulic pressure is released by energizing the solenoid of the hydraulic drive device according to an instruction from the controller. For this reason, the controller must recognize the crank angle (0 to 720 ° CA) while the engine is running, and control energization at a necessary timing in synchronization with this angle.

  However, if the crank angle is lost due to some reason such as engine rotation at engine start or stop, or rotation sensor failure or harness disconnection, the solenoid is energized due to crank angle synchronization. As a result, there is a problem that the intake valve and the piston collide with each other and the engine may be damaged.

JP 2007-303438 A JP 2004-052551 A

  An object of the present invention is to break down an internal combustion engine caused by a collision between an intake / exhaust valve and a piston in an internal combustion engine having a variable valve mechanism that makes the opening / closing timing and lift amount of the intake / exhaust valve variable by hydraulic pressure. It is an object of the present invention to provide a method for controlling an internal combustion engine and an internal combustion engine that can prevent the above-described problem.

  In order to achieve the above object, an internal combustion engine control method according to the present invention includes a rotating cam that opens and closes an intake / exhaust valve in conjunction with a crankshaft, and an opening / closing timing and lift amount of the intake / exhaust valve. In a control method of an internal combustion engine including a variable valve mechanism having a hydraulic drive device, a first signal for closing the intake / exhaust valve in synchronization with a crank angle of the crankshaft is sent to the hydraulic drive device. A first control step for transmitting and closing the intake / exhaust valve and a second signal for closing the intake / exhaust valve at the preset time when the crank angle is not synchronized. And a second control step for closing the intake / exhaust valves by transmitting to the driving device.

  In the internal combustion engine control method, the crank angle synchronization failure is recognized by the crank angle detection signal. As a result, by recognizing the crank angle synchronization failure using the standard cam crank angle detection signal, the intake and exhaust valves and pistons can be connected without requiring special equipment or complicated software. Can be prevented.

  In the control method for an internal combustion engine, the first signal and the second signal are pulse signals having a constant frequency. Thus, a plurality of intake and exhaust valves having different phases can be closed without complicating the device and control.

  In order to achieve the above object, an internal combustion engine of the present invention adjusts an opening / closing timing and a lift amount of an intake / exhaust valve, a rotating cam that opens / closes an intake / exhaust valve in conjunction with a crankshaft. In an internal combustion engine including a variable valve mechanism having a hydraulic drive device, a first signal for closing the intake and exhaust valves in synchronization with a crank angle of the crankshaft is transmitted to the hydraulic drive device. A control unit; a second control unit that transmits a second signal for closing the intake / exhaust valve to the hydraulic drive device at predetermined time intervals when the crank angle is out of synchronization; and Signal switching means for switching between the signal and the second signal.

  In the internal combustion engine, when the crank angle detection signal is recognized by the crank angle detection signal, the signal switching means is instructed to output the second signal.

  In the internal combustion engine, the first signal and the second signal are pulse signals having a constant frequency.

  According to the present invention, when the internal combustion engine is started, stopped, or when other crank angles are out of synchronization, the intake and exhaust valves are reliably closed by the second signal generated every preset time, Since the collision between the intake / exhaust valve and the piston can be prevented, the destruction of the internal combustion engine due to the collision can be prevented. Therefore, the safety of the internal combustion engine can be improved.

It is principal part sectional drawing of the internal combustion engine of embodiment of this invention. FIG. 2 is a cross-sectional view of a main part of an example of a variable valve mechanism part of the internal combustion engine of FIG. 1. FIG. 3 is a cross-sectional view of a main part when the variable valve mechanism of FIG. 2 is in operation. FIG. 4 is a cross-sectional view of a main part at the time of operation of the variable valve mechanism mechanism following FIG. 3. FIG. 5 is a cross-sectional view of a main part during operation of the variable valve mechanism mechanism following FIG. 4. It is a wave form diagram of the valve lift by the variable valve mechanism part of FIG. It is a block diagram of the controller of the internal combustion engine of FIG. It is a block diagram of the controller of FIG. It is a wave form diagram of the pulse signal output from the 1st control part of the controller of FIG. It is a wave form diagram of the pulse signal output from the 2nd control part of the controller of FIG.

  Hereinafter, an internal combustion engine according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a cross-sectional view of a main part of the internal combustion engine of the present embodiment. The internal combustion engine of the present embodiment is configured as, for example, a diesel engine 1 mounted on an automobile such as a truck. In addition, this invention is not limited to a diesel engine, It can also apply to a gasoline engine etc.

  This diesel engine (hereinafter simply referred to as an engine) 1 is supplied with fuel to air that has been compressed in the combustion chamber of the cylinder 2 and heated to self-ignite, and the cylinder is expanded by self-ignition at this time. 2 has a structure for extruding the piston 3 in the interior. FIG. 1 shows the time when the piston 3 is at the top dead center.

  The cylinder 2 is a cylindrical part that supports the reciprocating motion of the piston 3 and stores fuel gas, and a liner 2a is provided on the inner wall thereof. Further, a cooling passage 2b through which a cooling medium for cooling the cylinder flows is provided in a thick portion outside the liner 2a in the cylinder 2.

  Inside the cylinder 2, the piston 3 is installed in a state where the axis of the piston 3 coincides with the axis A of the cylinder 2 by design and can reciprocate along the liner 2 a on the inner wall of the cylinder 2. A cavity (combustion chamber) 4 is recessed in the center of the top surface of the piston 3. Although not particularly limited, a convex portion that protrudes upward is formed at the center of the bottom surface of the cavity 4 so that the depth of the cavity 4 gradually decreases toward the center. The piston 3 is connected to a crankshaft (not shown) through a connecting rod 5, and the reciprocating motion of the piston 3 is converted into rotational motion by the crankshaft.

  A cylinder head 6 is installed on the upper portion of the cylinder 2. In this cylinder head 6, an injector (fuel injection portion) 7 that directly injects fuel into the cavity 4 of the cylinder 2 is positioned at a position facing the center of the top surface of the piston 3 so as to coincide with the axis A of the cylinder 2. is set up. The injector 7 is constantly supplied with high-pressure fuel stored in a common rail (not shown).

  In the injector 7, a plurality of fine nozzle holes are formed at the protruding tip of the nozzle 7 a protruding into the cylinder 2, and fuel is simultaneously injected radially from the plurality of fine nozzle holes. The injection axis B of the fuel injected from each nozzle hole at the tip of the nozzle 7a is inclined with respect to the above-described axis A by a predetermined injection angle θ. This injection angle θ is set to an angle that allows the fuel to be accommodated in the cavity 4 in the cylinder 2 over the entire fuel injection period.

  In the cylinder head 6, an intake port 9 a and an exhaust port 9 b are installed on the left and right of the injector 7 so as to sandwich the injector 7. The intake port 9a is connected to the intake pipe 10a, and the exhaust port 9b is connected to the exhaust pipe 10b.

  The intake port 9a is provided with an intake valve 11a, and the exhaust port 9b is provided with an exhaust valve 11b. The intake valve 11a opens and closes between the cylinder 2 and the intake pipe 10a, and the exhaust valve 11b opens and closes between the cylinder 2 and the exhaust pipe 10b.

  These intake / exhaust valves 11a and 11b are mechanically connected to the variable valve mechanisms 15a and 15b, respectively. The variable valve mechanisms 15a and 15b are mechanisms that drive the intake and exhaust valves 11a and 11b.

  Next, FIG. 2 shows a cross-sectional view of an essential part of an example of the variable valve mechanism 15a (15b). In FIG. 2, one variable valve mechanism 15a (15b) and one valve 11a (11b) are shown.

  The variable valve mechanism 15a (15b) includes a rotating cam 16, a rocker arm 17, a valve spring 18, and a hydraulic drive device 19. Note that the hydraulic drive device 19 is used only for the variable valve mechanism 15a for the intake valve 11a, and the variable valve mechanism 15b for the exhaust valve 11b is not provided with the hydraulic drive device 19. A variable valve mechanism may be used.

  The rotating cam 16 presses the valve 11a (11b) via the rocker arm 17, thereby causing the valve 11a (11b) to open against the urging force of the valve spring 18 (the face portion in the valve 11a (11b)). Is a member pushed down in the direction away from the valve guide 20.

  A cam mountain (nose) 16n having a partly long radial distance from the center is formed on a part of the outer periphery of the rotating cam 16, and the entire cross-sectional shape of the rotating cam 16 (perpendicular to the extending direction of the camshaft 21). The cross section is formed in a substantially oval shape.

  The rotating cam 16 is provided on the camshaft 21. The camshaft 21 is provided with a number of rotating cams 16 corresponding to the number of valves along the axial direction thereof. The camshaft 21 is rotatably supported by a bearing and is connected to the crankshaft through a gear or a belt. Thereby, the rotating cam 16 is interlocked with the crankshaft.

  The rocker arm 17 is pivotally supported by a rocker shaft 22 disposed at one end in the longitudinal direction, and is rocked in conjunction with the rotation of the rotary cam 16. A valve 11 a (11 b) is connected to the other end side in the longitudinal direction of the rocker arm 17. FIG. 2 shows a state where the face portion of the valve 11a (11b) is separated from the valve guide 20 and the valve 11a (11b) is open.

  The valve spring 18 is a member that urges the valve 11 a (11 b) in the valve closing direction (a direction in which the face portion of the valve 11 a (11 b) approaches the valve guide 20), and is formed between the retainer 23 and a part of the cylinder head 6. It is installed in a compressed state at a position surrounding the stem portion of the valve 11a (11b).

  The hydraulic drive device 19 described above is a device that adjusts (changes) the opening / closing timing and lift amount of the valve 11a (11b), and includes a device main body 25 and a hydraulic tank (working fluid tank) 26.

  The hydraulic piston 27 of the apparatus body 25 has a position where one end thereof is not directly pressed by the rotating cam 16 in the rocker arm 17, that is, a pressing portion where the rotating cam 16 is pressed by the rocker arm 17, and the valve 11a (11b). ) Are connected to the valve connection part to which the connection is made.

  The hydraulic piston 27 is installed in the piston insertion hole 28 of the apparatus main body 25 so as to be vertically movable. In the piston insertion hole 28, the other end side of the hydraulic piston 27 communicates with the control chamber 29, and the upper surface of the other end side of the hydraulic piston 27 faces the control chamber 29.

  The control chamber 29 is connected to an inlet 31 of hydraulic oil (working fluid) via a check valve (first operating valve; check valve) 30 and further connected to the hydraulic tank 26 via an inflow pipe 32a. . The inlet side of the check valve 30 is the hydraulic tank 26 side, and the outlet side of the check valve 30 is the control chamber 29 side. The check valve 30 is automatically opened when the pressure in the control chamber 29 becomes negative, and introduces hydraulic oil in the hydraulic tank 26 into the control chamber 29 when the valve is opened.

  The control chamber 29 is connected to a hydraulic oil outlet 34 via a poppet valve (second operating valve; control valve) 33 and further connected to the hydraulic tank 26 via an outlet pipe 32b. The poppet valve 33 discharges hydraulic oil in the control chamber 29 to the hydraulic tank 26 when the valve is opened. The poppet valve 33 is composed of an electromagnetic valve, and its opening / closing operation is electrically controlled by the controller 35.

  Next, the slow closing operation of the intake valve 11a of the variable valve mechanism 15a will be described with reference to FIGS.

  First, as shown in FIG. 3, the rocker arm 17 is pressed by the cam crest 16 n of the rotating cam 16 to open the intake valve 11 a against the urging force of the valve spring 18 as usual. At that time, the poppet valve 33 is closed and the hydraulic piston 27 connected to the rocker arm 17 is also lowered at the same time, whereby the pressure in the control chamber 29 becomes negative and the check valve 30 is automatically opened. As a result, the hydraulic oil in the hydraulic tank 26 is sucked and filled into the control chamber 29 through the inlet 31.

  Subsequently, as shown in FIG. 4, when the rotary cam 16 passes the peak position and the intake valve 11 a starts the valve closing operation as usual, the valve 11 a moves in the valve closing direction by the urging force of the valve spring 18. . As a result, the hydraulic piston 27 also moves in the valve closing direction. At this time, the poppet valve 33 is closed, and the hydraulic oil in the control chamber 29 is compressed as the hydraulic piston 27 rises, and the pressure in the control chamber 29 rises to a positive pressure. As a result, the check valve 30 is automatically closed, the pressure in the control chamber 29 suddenly increases, and the force of the valve spring 18 and the balance valve 11a continue to be opened.

  Thereafter, by energizing the solenoid for driving the poppet valve 33 at a desired valve timing to open the poppet valve 33, the hydraulic oil in the control chamber 29 is supplied from the outlet 34 to the hydraulic tank as shown in FIG. Escape to 26. As a result, the pressure in the control chamber 29 decreases, the urging force of the valve spring 18 raises the hydraulic piston 27 and the intake valve 11a, and the intake valve 11a closes. In this way, the slow closing operation of the intake valve 11a is performed. FIG. 6 shows the valve lift amount by the variable valve mechanism 15a (15b). The symbol PC indicates the normal valve lift amount by the rotating cam 16 that does not perform the slow closing operation, and the symbol PO indicates the valve lift amount during the slow closing operation.

  Next, the controller 35 that controls the operation of the hydraulic drive device 19 in the engine 1 of the present embodiment will be described with reference to FIGS.

  FIG. 7 is a circuit block diagram of the controller 35, and FIG. 8 is a block diagram of the controller 35 (extracted only for one solenoid). The controller 35 controls the operation of the drive solenoid of the poppet valve 33 of the hydraulic drive device 19 shown in FIG. 2 based on the cam / crank signal CCS, so that the valve closing timings of the intake and exhaust valves 11a and 11b are closed. And a function of adjusting the lift amount.

  As shown in FIG. 8, the controller 35 includes a first control unit 36, a second control unit 37, and a selector circuit (signal switching means) 38. The outputs of the first controller 36 and the second controller 37 are electrically connected to the input terminals CS1 and CS2 of the selector circuit 38, respectively.

  The first control unit 36 is a pulse generation circuit that transmits a pulse signal (first signal) for closing the intake and exhaust valves 11 a and 11 b to the hydraulic drive device 19 in synchronization with the crank angle. That is, the first control unit 36 is a pulse generation circuit that generates a pulse signal (first signal) for performing control for closing the intake and exhaust valves 11a and 11b by the hydraulic drive device 19 in synchronization with the crank angle. is there.

  FIG. 9 shows a pulse signal for forced closing that is output from the first control unit 36 and transmitted to the poppet valve 33. This pulse signal is output in synchronization with the crank angle. Thus, by making the control signal a pulse signal, the burden on the driving solenoid of the poppet valve 33 can be reduced, and the power consumption can be reduced. The pulse signal is a constant frequency pulse signal having a fixed number of repetitive pulse signals within a predetermined time (pulse width Tw1) (the signal output from the first control unit 36 is a single pulse signal). Is a pulse signal having a constant frequency via a driver circuit (not shown) in the subsequent stage). It is possible to adjust (change) the valve closing time and lift amount of the intake / exhaust valves 11a and 11b by duty control of this pulse signal (controlling the ratio of the pulse width to control the magnitude of the average current). it can.

  Also, the first control unit 36 shown in FIG. 8 determines whether or not the crank angle can be synchronized based on the cam / crank signal CCS. The pulse signal (second signal) output from the unit 37 is instructed to be transmitted to the drive solenoid of the poppet valve 33.

  The second control unit 37 transmits a pulse signal (second signal) for closing the intake / exhaust valves 11a and 11b to the hydraulic drive device 19 every predetermined time when synchronization of the crank angle is lost. It is a generation circuit. That is, the second control unit 37 controls the hydraulic drive device 19 to close the intake and exhaust valves 11a and 11b when the engine 1 starts, stops, or fails to synchronize the crank angle due to other reasons such as failure. Is a pulse generation circuit that generates a pulse signal (second signal) for performing the above operation at preset time intervals (that is, in synchronization with a clock signal).

  FIG. 10 shows a pulse signal for forced closing that is output from the second control unit 37 and transmitted to the poppet valve 33. This pulse signal is output at regular intervals. The period T of the pulse signal is not particularly limited, but is, for example, 50 ms. Further, the pulse width Tw2 is not particularly limited, but is, for example, 5 ms. Reference symbols Cy1 to Cy4 denote cylinders. Also in this case, each pulse signal is a pulse signal having a constant frequency having a fixed number of repetitive pulse signals within a predetermined time (pulse width Tw2) (a signal output from the second control unit 37 is Although it is a single pulse signal, it becomes a pulse signal with a constant frequency via a driver circuit (not shown) in the subsequent stage.

  The selector circuit 38 is a switching circuit that selects and switches which of the pulse signal of the first control unit 36 and the pulse signal of the second control unit 37 is transmitted to the driving solenoid of the poppet valve 33. The selector circuit 38 has a 2-input / 1-output configuration. The selector circuit 38 performs the switching described above based on the signal sent from the first control unit 36 to the determination terminal S. Instead of the selector circuit 38, an OR circuit may be used.

  Next, a method for controlling the engine 1 according to the present embodiment will be described.

  In the control of the engine 1 according to the present embodiment, the intake and exhaust valves 11a and 11b are closed in synchronism with the crank angle, and the intake / exhaust at every preset time when the synchronization of the crank angle is lost. And a second control step for closing the exhaust valves 11a and 11b. Hereinafter, the case where the intake valve 11a is closed in the first and second control steps will be described as an example, but the same applies to the exhaust valve 11b.

  First, the first control unit 36 determines whether or not synchronization at the crank angle can be achieved based on the cam / crank signal CCS. When synchronization can be established, the crank angle (0-720 ° CA) is recognized, and a pulse signal (see FIG. 9) for closing the intake valve 11a in synchronization with the crank angle is sent from the first controller 36 to the selector. The signal is transmitted to the driving solenoid of the poppet valve 33 via the circuit 38. Thus, the poppet valve 33 can be opened and the intake valve 11a can be closed at an optimal timing synchronized with the crank angle.

  In this mode, for example, the above-described slow closing control of the intake valve 11a is performed by a pulse signal synchronized with the crank angle. In this case, the valve lift amount is the valve lift amount PO during the slow closing operation shown in FIG. Thus, by closing the intake valve 11a late, for example, even in an engine 1 without an intake throttle, the intake work can be reduced and the compression work can be reduced in a low load range, and the compression stroke can be shortened with respect to the expansion stroke. Therefore, the illustrated work in the cycle can be improved.

  On the other hand, when the first control unit 36 determines that the crank angle cannot be synchronized based on the cam / crank signal CCS (when the crank angle is not synchronized), the first control unit 36 outputs the selector circuit 38 to the second control unit 37. The pulse signal is instructed to be transmitted to the drive solenoid of the poppet valve 33.

  That is, when the engine 1 is started, stopped, or when the crank angle is lost due to some reason, a pulse signal (see FIG. 10) for closing the intake valve 11a at a preset time is sent to the second control unit. 37 to the driving solenoid of the poppet valve 33 via the selector circuit 38. As a result, when the synchronization of the crank angle of the engine 1 is lost, the poppet valve 33 of the hydraulic drive device 19 can be opened and the intake valve 11a can be closed every preset time.

  In this mode, the intake valve 11a is not slowly closed, and the valve lift amount becomes the normal valve lift amount PC by the rotating cam 16 shown in FIG. In this mode, the valve signal for closing the valve continues to be applied even during a period other than the valve slow closing period in which the energization to the driving solenoid of the poppet valve 33 is not required, and the solenoid moves unnecessarily. There is no adverse effect on the operation of 11a.

  As described above, in the engine 1 of the present embodiment, when the synchronization of the crank angle at which the controller 35 cannot have the crank angle information is lost, the intake valve 11a is closed every preset time, Since the collision between the valve 11a and the piston 3 at the time of crank angle synchronization failure can be prevented, the engine 1 can be prevented from being destroyed due to the collision. Therefore, the safety of the engine 1 including the variable valve mechanism mechanisms 15a and 15b can be improved.

  Even when the crank angle is lost, the controller 35 (second control unit 37) can transmit a control signal to the drive solenoid of the poppet valve 33 of the hydraulic drive device 19, so that the engine 1 can be started and operated. Variable valve timing (VVT) control is possible in the entire stop process.

  In addition, by recognizing the crank angle synchronization failure by the cam / crank signal CCS provided in the standard engine 1, the intake valve 11a and the piston can be used without requiring any special device or complicated software. 3 can be prevented.

  The control method for an internal combustion engine and the internal combustion engine of the present invention close the intake / exhaust valves every predetermined time when the crank angle is out of synchronization, thereby starting or stopping the internal combustion engine or other crank angles. In this case, the collision between the intake / exhaust valve and the piston can be prevented, and the internal combustion engine can be prevented from being destroyed due to the collision. Available.

1 Diesel engine (internal combustion engine)
2 Cylinder 3 Piston 4 Cavity (combustion chamber)
11a Intake valve 11b Exhaust valve 15a Variable valve mechanism 15b Variable valve mechanism 16 Rotating cam 19 Hydraulic drive unit 25 Device body 26 Hydraulic tank (working fluid tank)
27 Hydraulic piston 28 Piston insertion hole 29 Control chamber 30 Check valve (first actuating valve)
31 Inlet port 33 Poppet valve (second operating valve)
34 Outlet 35 Controller 36 First controller 37 Second controller 38 Selector circuit (signal switching means)

Claims (6)

Control of an internal combustion engine comprising a variable valve mechanism having a rotary cam that opens and closes an intake / exhaust valve in conjunction with a crankshaft, and a hydraulic drive device that adjusts the opening / closing timing and lift amount of the intake / exhaust valve In the method
A first control step of transmitting a first signal for closing the intake / exhaust valve in synchronization with a crank angle of the crankshaft to the hydraulic drive device and closing the intake / exhaust valve;
Second control for closing the intake / exhaust valve by transmitting a second signal for closing the intake / exhaust valve to the hydraulic drive device at the preset time when the crank angle is out of synchronization. And a control method for the internal combustion engine.   2. The control method of an internal combustion engine according to claim 1, wherein the crank angle synchronization failure is recognized by the crank angle detection signal.   The method of controlling an internal combustion engine according to claim 1 or 2, wherein the first signal and the second signal are pulse signals having a constant frequency. In an internal combustion engine comprising a variable valve mechanism having a rotating cam that opens and closes an intake / exhaust valve in conjunction with a crankshaft, and a hydraulic drive device that adjusts the opening / closing timing and lift amount of the intake / exhaust valve.
A first control unit that transmits a first signal for closing the intake and exhaust valves to the hydraulic drive device in synchronization with a crank angle of the crankshaft;
A second control unit that transmits a second signal for closing the intake / exhaust valve to the hydraulic drive device at predetermined time intervals when the crank angle is out of synchronization;
An internal combustion engine comprising signal switching means for switching between the first signal and the second signal.   5. The internal combustion engine according to claim 4, wherein when the crank angle detection signal is recognized by the crank angle detection signal, the signal switching means is instructed to output the second signal.   The internal combustion engine according to claim 4 or 5, wherein the first signal and the second signal are pulse signals having a constant frequency.

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