WO2019187645A1

WO2019187645A1 - Control device for internal combustion engine

Info

Publication number: WO2019187645A1
Application number: PCT/JP2019/003949
Authority: WO
Inventors: 賢一藤澤; 豊原　正裕; 鈴木　邦彦
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2018-03-28
Filing date: 2019-02-05
Publication date: 2019-10-03
Also published as: JPWO2019187645A1

Abstract

A control device for an internal combustion engine, wherein an amount of air suctioned into a cylinder of the internal combustion engine is accurately calculated. An ECU 108 for controlling an engine 100 having camshafts 121, 209 that drive an intake valve 102 and an exhaust valve 103 so as to open and close, and cam angle sensors 122, 209a that detect the angle of rotation of the camshafts 121, 209. The camshaft 121 has a reference angle formation unit 220 configured so as to be detected by the cam angle sensor 122, and the reference angle formation unit 220 is provided at an angle position corresponding to (matching) a valve closing timing of at least the intake valve 102.

Description

Control device for internal combustion engine

The present invention relates to a control device for an internal combustion engine.

In recent years, many internal combustion engines for vehicles are provided with a variable valve timing mechanism for the purpose of improving fuel consumption and reducing exhaust gas. With this variable valve timing mechanism, it is possible to arbitrarily control the operating angle of an intake valve that supplies air to a cylinder of an internal combustion engine and an exhaust valve that discharges combustion gas from the cylinder.

The control device for an internal combustion engine provided with such a variable valve timing mechanism controls the intake valve or the exhaust valve to a desired operating angle by the variable valve timing mechanism, as well as the injection timing of the fuel injection device and the ignition timing of the ignition device. Is controlled in accordance with the operating state of the internal combustion engine, thereby improving the fuel consumption, exhaust, output, and driving performance of the internal combustion engine.

In Patent Document 1, the cam position (angle) is calculated from the output signals of the crank angle sensor and the cam angle sensor, and the cam position is calculated by performing various correction control learning the variation of the components of the variable valve timing mechanism. A control device for an internal combustion engine is disclosed.

Further, in the control device for an internal combustion engine disclosed in Patent Document 1, abnormality determination of the output signal is performed from the form of the output signals of the crank angle sensor and the cam angle sensor, and if it is determined to be abnormal, fail-safe control is performed. carry out. Therefore, in this internal combustion engine control device, a stable combustion state of the internal combustion engine can be realized even when the variable valve timing mechanism is in a normal state or an abnormal state.

JP 2013-167223 A

However, in the control device for an internal combustion engine described above, the control of the operation angle of the intake valve and the exhaust valve by the variable valve timing mechanism does not consider the closing of the intake valve or the exhaust valve. Cannot be determined, and the amount of air in the cylinder cannot be calculated accurately.

As a result, in a control device for an internal combustion engine, during steady operation in which the combustion state is relatively constant, there is no problem in the accuracy of air amount calculation even if the air amount in the cylinder is not determined. At the time of transient operation in which the operation timing of the intake valve by the variable valve timing mechanism changes, the air amount calculation accuracy becomes insufficient unless the air amount in the cylinder is determined.

Therefore, the present invention has been made paying attention to the above problems, and an object of the present invention is to accurately calculate the amount of air taken into the cylinder of the internal combustion engine in the control device for the internal combustion engine.

In order to solve the above-described problem, there is provided a control device for an internal combustion engine that controls an internal combustion engine having a camshaft that opens and closes an intake valve and an exhaust valve, and a cam angle sensor that detects a rotation angle of the camshaft. The shaft has a reference angle forming portion configured to be detected by a cam angle sensor, and the reference angle forming portion is provided at an angular position corresponding to at least the valve closing timing of the intake valve.

According to the present invention, the amount of air taken into the cylinder of the internal combustion engine can be accurately calculated in the control device for the internal combustion engine.

It is a figure explaining the principal part of the engine concerning an embodiment. It is a perspective view explaining the structure of a variable valve timing mechanism. It is a figure explaining the detection timing of a cam angle sensor. It is sectional drawing explaining the structure of a variable valve timing mechanism. It is a functional block diagram explaining ECU. It is a figure explaining the relationship between each sensor signal concerning each prior art example, and each stroke of an engine. It is a figure explaining an example of the detection timing of a cam angle sensor. It is a figure explaining the relationship between each sensor signal concerning each embodiment, and each stroke of an engine. It is a block diagram explaining the function in ECU. It is a flowchart explaining the process of the fuel injection control by ECU. It is a flowchart explaining the request ignition timing arithmetic operation by ECU. It is a figure explaining the comparison result of the air fuel ratio control by the control device of the conventional internal combustion engine and the air fuel ratio control by the control device of the internal combustion engine to which the present invention is applied during the transient operation of the engine. It is a figure explaining the detection timing of the cam angle sensor concerning 2nd Embodiment. It is a figure explaining the detection timing of the cam angle sensor concerning 3rd Embodiment.

[engine]
A main part of an internal combustion engine (hereinafter referred to as engine 100) according to an embodiment of the present invention will be described. In the embodiment, the case where the engine 100 is a four-cycle engine 100 having a plurality of cylinders will be described as an example. Engine 100 is a direct injection spark ignition internal combustion engine that directly injects fuel into each cylinder and ignites sparks on the injected fuel.

FIG. 1 is a diagram for explaining a main part of an engine 100 according to an embodiment.

As shown in FIG. 1, the engine 100 is provided with a piston 101, an intake valve 102, and an exhaust valve 103. The intake air passes through an air flow meter (AFM) 118 and is throttled. It enters the valve 117 and is supplied from a collector 113 serving as a branching portion to a combustion chamber 119 of a cylinder (not shown) of the engine 100 through an intake pipe 109 and an intake valve 102.

The intake valve 102 is driven to open and close (open or close) by a cam 201 (see FIG. 2) provided on the intake side camshaft 121. Is provided with a cam angle sensor 122 for detecting the rotation angle of the intake camshaft 121.

The exhaust valve 103 is also driven to open and close (open or close) by a cam 210 (see FIG. 2) provided on the exhaust side camshaft 209. Is provided with a cam angle sensor 209a for detecting the rotation angle of the exhaust camshaft 209.

Fuel supplied from a fuel tank (not shown) is injected into the combustion chamber 119 of the engine 100 by the fuel injection valve 104. The combustion chamber 119 is provided with an ignition plug 105, and the fuel supplied to the combustion chamber 119 explodes when the ignition plug 105 is ignited.

The piston 101 is pushed down by the explosion of fuel in the combustion chamber 119, and the crankshaft 116 connected to the piston 101 rotates in conjunction with the depression of the piston 101. The rotation of the crankshaft 116 is transmitted to a transmission (not shown) and becomes a driving force of the engine 100.

The rotation angle of the crankshaft 116 is detected by a crank angle sensor 114 provided outside the crankshaft 116 in the circumferential direction. The crank angle sensor 114 detects the rotation angle of the crankshaft 116 around the rotation axis by detecting an angle detector 115 (projection or groove) provided on the crankshaft 116.

The exhaust gas after combustion is discharged to the exhaust pipe 110 through the exhaust valve 103. The exhaust pipe 110 is provided with a three-way catalyst 111 for purifying exhaust gas. An air-fuel ratio sensor 112 that detects an air-fuel ratio in the exhaust gas is provided upstream of the three-way catalyst 111 in the exhaust gas flow direction.

A knock sensor 107 is provided in the cylinder block of the engine 100, and the knock sensor 107 detects an abnormal noise (knocking) generated when the engine 100 is abnormally burned.

The vehicle (not shown) is provided with an accelerator opening sensor 120, and the accelerator opening sensor 120 detects the accelerator opening according to the amount of depression of the driver's accelerator (not shown). Is done.

The crank angle sensor 114, the

cam angle sensors

122 and 209a, the air flow meter 118, the air-fuel ratio sensor 112, the knock sensor 107, and the accelerator opening sensor 120 are connected to the ECU 108. The output signal from is input to the ECU 108.

The ECU 108 calculates the required torque for the engine 100 based on the output signal of the accelerator opening sensor 120 and determines the idle state. The ECU 108 calculates the intake air amount necessary for the engine 100 based on the calculated required torque, and outputs an opening signal corresponding to the intake air amount to the throttle valve 117.

Further, the ECU 108 outputs an injection control signal to the fuel injection valve 104 and outputs an ignition signal to the spark plug 105. The ECU 108 performs feedback control of the ignition signal based on the detection of knocking by the knock sensor 107.

As described above, the ECU 108 performs various controls on the engine 100 (internal combustion engine) and corresponds to a control device for the internal combustion engine.

Here, a variable valve timing mechanism 123 is provided on the intake camshaft 121 and the exhaust camshaft 209 described above. The variable valve timing mechanism 123 is a mechanism that changes the valve timing of the intake valve 102 and the exhaust valve 103 by changing the rotational phase of the intake camshaft 121 or the exhaust camshaft 209 relative to the crankshaft 116. The valve timings of the intake valve 102 and the exhaust valve 103 are calculated by the ECU 108 based on detection signals of the

cam angle sensors

122 and 209a.

The variable valve timing mechanism 123 is not limited to the one that changes the valve timing of the intake valve 102 of the embodiment, and is applied to the exhaust valve 103 or both the intake valve 102 and the exhaust valve 103. Also good.

[Variable valve timing mechanism]
Next, the structure of the variable valve timing mechanism 123 according to the embodiment will be described.

FIG. 2 is a perspective view for explaining the structure of the variable valve timing mechanism 123.
FIG. 3 is a diagram for explaining the detection timing of the cam angle sensor 122.
FIG. 4 is a cross-sectional view illustrating the structure of the variable valve timing mechanism 123, and shows the connection relationship between the oil control valve 207 and the variable valve timing mechanism 123.

As shown in FIG. 2, a variable phase cam pulley 202 is provided at one end of the intake camshaft 121, and the variable phase cam pulley 202 is a continuously variable phase type in which the rotational phase continuously changes. . The phase variable cam pulley 202 is formed with a gear over the entire circumference in the circumferential direction around the rotation axis of the phase variable cam pulley 202.

The intake side camshaft 121 has a reference angle forming part 220 configured such that the reference angle of the intake side camshaft 121 is detected by the cam angle sensor 122. The reference angle forming portion 220 of the intake camshaft 121 is provided at an angular position corresponding to at least the valve closing timing (valve closing position IVC) of the intake valve 102.
The reference angle forming part 220 is a protrusion provided to protrude radially outward from the outer periphery of the cam rotor 208 having a disk shape provided on the outer periphery of the intake side camshaft 121. The reference angle forming unit 220 may be provided by any method that is integral with or separate from the camshaft 121.

As shown in FIG. 3, in the embodiment, two reference angle forming portions 220 are provided at 180 ° positions that are symmetrical with respect to the rotation center of the cam rotor 208. Each reference angle forming section 220 is provided at a position corresponding to (coincidence with) a position where the intake valve 102 is closed (valve closing position IVC) as the cam 201 (intake side camshaft 121) rotates.

Therefore, the ECU 108 detects the reference angle forming unit 220 (protrusion) with the cam angle sensor 122, thereby closing the intake valve 102 and the process of the detection timing determined to be closed (in the embodiment, the intake air Process) can be determined.

In the embodiment, the case where a total of two reference angle forming units 220 are provided at symmetrical 180 ° positions has been described. However, the reference angle forming unit 220 may be a position where it is possible to determine whether the intake valve 102 is closed. It is not limited to this, and it may be one or three or more.

In the above-described embodiment, the reference angle forming unit 220 is described as an example of a protrusion protruding from the outer periphery of the cam rotor 208 to the outer side in the radial direction of the rotation shaft. However, the reference angle is determined by the cam angle sensor 122. Various configurations are conceivable as long as they can be detected. For example, the reference angle forming portion 220 is a groove 220A or a hole that is recessed radially inward from the outer periphery of the cam rotor 208 having a disk shape provided on the outer periphery of the intake camshaft 121 (see the dotted line in FIG. 3). And may be a groove 220A or a hole. In this case, the groove 220A or the hole is provided at an angular position corresponding to at least the valve closing timing (the valve closing position IVC) of the intake valve 102. Further, the reference angle forming unit 220 may be configured to be set at an angular position corresponding to the intake stroke, the compression stroke, the explosion stroke, and the exhaust stroke of the engine 100.

Referring back to FIG. 2, a cam pulley 203 whose rotational phase does not change is provided at one end of the exhaust side camshaft 209. The cam pulley 203 is formed with a gear over the entire circumference in the circumferential direction around the rotation axis. The gear is engaged with the gear of the variable phase cam pulley 202 and combined.

A crank pulley 204 is fixed to one end of the crankshaft 116 described above, and a gear is formed on the crank pulley 204 over the entire circumference in the circumferential direction around the rotation axis of the crank pulley 204.

Also, an oil pump 205 is provided at one end of the crankshaft 116, and the oil pump 205 rotates in synchronization with the rotation of the crankshaft 116, thereby discharging oil and generating hydraulic pressure. As a result, lubrication in the engine 100 and oil supply to a hydraulically driven actuator are performed.

A timing belt 206 is wound around the phase variable cam pulley 202, the cam pulley 203, and the crank pulley 204. The phase variable cam pulley 202 and the cam pulley 203 are connected to the crank pulley 204 via the timing belt 206. Driven by.

The phase variable cam pulley 202 includes an actuator driven by hydraulic pressure.

As shown in FIG. 4, a cam housing 251 is provided on the inner peripheral side of the phase variable cam pulley 202, and a vane 252 fixed to the intake side camshaft 121 is provided inside the cam housing 251. ing.

A space is formed around the vane 252 by the vane 252 and the cam housing 251. Within this space, the vane 252 can operate around the rotation axis.

A space formed by the vane 252 and the cam housing 251 is partitioned into an advance chamber 253 and a retard chamber 254 by the vane 252, and the advance chamber 253 is connected to the phase advance hydraulic passage 281. The retard chamber 254 is connected to the phase retard hydraulic passage 282. The phase advance hydraulic passage 281 and the phase retard hydraulic passage 282 are connected to an oil control valve (Oil Control Valve: OCV) 207.

The oil control valve 207 includes a solenoid 255, a plunger 256, a housing 257, a spool 258, and a spring 259.

In the oil control valve 207, the spool 258 is provided so as to be movable in the axial direction (left-right direction in FIG. 4), and the axial movement of the spool 258 is controlled by energizing or de-energizing the solenoid 255. In the oil control valve 207, when the solenoid 255 is not energized, the spool 258 is pressed by the spring 259 and is positioned in the right direction in FIG. In order to press in the direction, the spool 258 moves to the left in FIG. 4 against the pressing force of the spring 259. The amount of movement of the spool 258 in the left direction increases in proportion to the amount of current supplied to the solenoid 255.

The housing 257 includes a hydraulic pressure supply port 261, an advance port 262, a retard port 263, and a drain port 260. These hydraulic supply port 261, advance port 262, retard port 263, drain The ports 260 are connected to an oil passage 280, a phase advance hydraulic passage 281, a phase retard hydraulic passage 282, and a drain passage (not shown), respectively.

The variable valve timing mechanism 123 is not limited to the structure described above, and any known variable valve timing mechanism can be applied.

[ECU]
Next, functions of the ECU 108 according to the embodiment will be described.

FIG. 5 is a functional block diagram for explaining the ECU 108 according to the embodiment.

The ECU 108 includes an input circuit 301, an A / D (Analog-to-Digital Converter) 302, a CPU (Central Processing Unit) 303, a ROM (Read Only Memory) 304, a RAM (Random Access Memory) 305, and the like. , And a microcomputer having an output circuit 306.

When an analog input signal 300 (for example, an output signal from the air flow meter 118 or the accelerator opening sensor 120 described above) is input, the input circuit 301 removes a noise component from the input signal 300, and The input signal 300 is output to the A / D converter 302.

The A / D conversion unit 302 converts the analog input signal 300 received from the input circuit 301 into a digital signal and outputs it to the CPU 303.

The CPU 303 takes in the digital input signal 300 converted by the A / D conversion unit 302 and executes the fuel injection control program stored in the ROM 304 and other control programs, whereby the fuel injection valve 104 and other Perform device control, diagnosis, etc.

The calculation result by the CPU 303 and the conversion result by the A / D conversion unit 302 are temporarily stored in the RAM 305, and the calculation result is output as a control signal 307 via the output circuit 306. In the engine 100, the fuel injection valve 104, the ignition coil 106, and the like are controlled by the control signal 307. Note that the control signal 307 calculated by the CPU 303 based on the input signal 300 such as the air flow meter 118 and the accelerator opening sensor 120 corresponds to an operating condition described later.

[Relationship between Sensor Signals and Processes of Engine 100 According to Conventional Example]
Next, the relationship between each sensor signal and each stroke of the engine 100 according to the conventional example will be described.

FIG. 6 is a diagram for explaining the relationship between each sensor signal and each stroke of the engine 100 according to the conventional example, and the uppermost stage in FIG. 6 is a time chart of the output signal of the cam angle sensor 122 provided in the engine 100. The second stage from the top in the figure is a time chart of the output signal of the crank angle sensor 114 provided in the engine 100, and the third stage from the top in the figure is a time chart of the stroke of the engine 100. Yes, the lowermost stage in the figure shows the opening degree sensor signals of the accelerator opening degree sensor 120 and the throttle valve 117 when the engine 100 is in a transient operation. In the embodiment, the case where engine 100 has four cylinders is illustrated, and therefore the cycle of the output signal of cam angle sensor 122 occurs every 180 degrees.

As shown in FIG. 6, in the conventional engine 100, the rotation angle of the intake camshaft 121 is calculated based on the rotation angle of the crankshaft 116 detected by the crank angle sensor 114, and the rotation of the intake camshaft 121 is calculated. The valve closing position (Intake Valve Close: IVC) of the intake valve 102 was calculated from the angle. Here, since the intake side camshaft 121 and the intake valve 102 are integrally provided, the position of the intake valve 102 is physically determined from the rotation angle of the intake side camshaft 121.

On the other hand, in the engine 100, a number of components such as a timing belt 206, a phase variable cam pulley 202, and a cam pulley 203 are interposed between the crankshaft 116 and the intake camshaft 121, for example. For this reason, component errors, combination errors, and the like are accumulated, resulting in variations in the rotation angle of the intake camshaft 121 calculated from the rotation angle of the crankshaft 116.

As a result, the valve closing position IVC of the intake valve 102 calculated from the rotation angle of the intake camshaft 121 varies, and the amount of air in the cylinder cannot be obtained accurately.

As shown in the lowermost stage of FIG. 6, in the engine 100, during the transient operation of the engine 100, the engine 100 is controlled according to the opening degree of the throttle valve 117 controlled by the ECU 108 based on the output signal of the accelerator opening degree sensor 120. The amount of air taken into the engine 100 increases, and the amount of air taken into the cylinder of the engine 100 is physically determined at the timing when the intake valve 102 is closed (valve closing position IVC).

As described above, during the transient operation of the engine 100, when the calculation of the fuel injection control and the ignition timing control is determined and executed before the air amount in the cylinder is physically determined (valve closing position IVC), the accelerator is Various corrections need to be made from recognized values such as changes in the opening degree, changes in the throttle valve 117, and the control position of the variable valve timing mechanism 123 obtained from the cam angle sensor 122.

However, in the ECU 108, the timing at which the amount of air in the cylinder is determined is corrected (varied in the calculated valve closing position IVC of the intake valve 102) or affected by the variation in the variable valve timing mechanism 123. The accuracy of control cannot be improved. As a result, at the time of transient operation of the engine 100, sufficient accuracy of the desired air-fuel ratio control cannot be ensured, and many man-hours are required to improve the accuracy of the air-fuel ratio control, and the air-fuel ratio control becomes complicated. turn into.

Therefore, in the embodiment of the present invention, the reference angle forming portion 220 (protrusion) of the cam rotor 208 provided on the intake side camshaft 121 is provided at an angular position corresponding to the valve closing position IVC of the intake valve 102. Based on the detection result of the reference angle forming unit 220 by the cam angle sensor 122, the valve closing position IVC of the intake valve 102 can be accurately detected. Therefore, even during the transient operation of engine 100, the amount of air in the cylinder can be accurately calculated.

FIG. 7 is a diagram for explaining an example of the detection timing of the cam angle sensor 122 according to the embodiment of the present invention. In FIG. 7, the cam angle for detecting the opening / closing operation (lift amount) of the intake valve 102 and the rotation angle of the intake camshaft 121 in a predetermined one of the four cylinders (cylinders) provided in the engine 100. The relationship with the detection signal of the sensor 122 is shown.

As shown in FIG. 7, in the embodiment, the cam angle sensor 122 detects a reference angle forming portion 220 (protrusion) provided on the cam rotor 208, and thereby the timing corresponding to the valve closing position IVC of the intake valve 102. The ECU 108 can accurately detect the closing timing of the intake valve 102.

The detection timing of the cam angle sensor 122 is preferably coincident with the valve closing position IVC of the intake valve 102. However, it is not completely coincident as long as it does not affect the calculation accuracy of the air amount in the cylinder. May be. For example, the detection timing of the cam angle sensor 122 may be within a predetermined set angle (for example, ± 0.3 deg) with respect to the valve closing position IVC of the intake valve 102.

Here, the range that does not affect the calculation accuracy of the air amount in the cylinder differs depending on the cylinder volume per cylinder of the engine 100, the operation lift amount of the intake valve 102, the open / close time, and the like, and therefore the engine to which the present invention is applied. It is desirable to set according to 100 specifications.

[Relationship between Sensor Signals and Processes of Engine According to Embodiment of the Present Invention]
Next, the relationship between each sensor signal and each stroke of the engine 100 according to the embodiment of the present invention will be described.

FIG. 8 is a diagram for explaining the relationship between each sensor signal and each stroke of the engine 100 according to the conventional example, and the uppermost stage in FIG. 8 is a time chart of the output signal of the cam angle sensor 122 provided in the engine 100. The second stage from the top in the figure is a time chart of the output signal of the crank angle sensor 114 provided in the engine 100, and the third stage from the top in the figure is a time chart of the stroke of the engine 100. Yes, the lowermost stage in the figure shows the opening degree sensor signals of the accelerator opening degree sensor 120 and the throttle valve 117 when the engine 100 is in a transient operation. In the embodiment, the case where engine 100 has four cylinders is illustrated, and therefore the cycle of the output signal of cam angle sensor 122 occurs every 180 degrees.

As shown in FIG. 8, the cam angle sensor 122 detects the timing of the valve closing position IVC of the intake valve 102 by detecting a reference angle forming portion 220 (protrusion) provided on the cam rotor 208. Thus, the valve closing position IVC of the intake valve 102 can be accurately detected. Thus, the ECU 108 can accurately calculate the amount of air in the cylinder after the intake valve 102 is closed, and calculates the fuel injection amount based on this amount of air so that a desired air-fuel ratio is obtained. The ECU 108 can inject a predetermined amount of fuel into the cylinder from the fuel injection valve 104 by controlling the fuel injection valve 104 based on the calculation result of the fuel injection amount.

When the ECU 108 determines that the fuel injection amount calculated at the valve closing position IVC of the intake valve 102 is insufficient by a predetermined threshold or more than the required fuel injection amount, the ECU 108 performs the subsequent stroke (for example, the compression stroke). Interrupt injection is performed and adjustment is performed so that a desired air-fuel ratio is obtained.

Here, the control block of the ECU 108 will be described.

FIG. 9 is a block diagram for explaining functions in the ECU 108.

As shown in FIG. 9, the ECU 108 includes an air amount calculation unit 801, a required fuel injection amount calculation unit 802, an interrupt fuel injection calculation unit 803, and a required ignition timing calculation unit 804.

The air amount calculation unit 801 receives the detection signal output from the air flow meter (AFM) 118 and the detection signal output from the cam angle sensor 122, and calculates the air amount in the cylinder based on these detection signals. To do.

The requested fuel injection amount calculation unit 802 receives the operating conditions of the engine 100, the detection signal of the crank angle sensor 114, and the like, and the detection timing of the reference angle detection unit 220 by the cam angle sensor 122 calculated by the air amount calculation unit 801. The required fuel injection amount is calculated based on the air amount in the cylinder.

The interrupt fuel injection calculation unit 803 determines that the fuel injection amount calculated from at least the air amount at the detection timing of the reference angle forming unit 220 is less than the required fuel injection amount calculated by the required fuel injection amount calculation unit 802. An interruption fuel injection amount is calculated, and an arithmetic process for outputting the interruption fuel injection amount to the fuel injection valve 104 is performed.

The ECU 108 controls the fuel injection valve 104 based on the required fuel injection amount calculated by the required fuel injection amount calculation unit 802 and the interrupt fuel injection amount calculated by the interrupt fuel injection calculation unit 803, The valve 104 injects fuel into the cylinder based on these fuel injection amounts.

The control of the fuel injection valve 104 performed by the ECU 108 based on the required fuel injection amount and the interrupt fuel injection amount is referred to as fuel injection control.

The requested ignition timing calculation unit 804 receives the operating conditions of the engine 100, the detection signal of the crank angle sensor 114, and the like, and the cylinder at the detection timing of the reference angle forming unit 220 by the cam angle sensor 122 calculated by the air amount calculation unit 801. The required ignition timing is calculated on the basis of the amount of air inside and is output to the ignition coil 106. The ignition coil 106 generates a high current for igniting the ignition plug 105, and supplies the high current to the ignition plug 105 at the required ignition timing, so that the ignition plug 105 performs ignition at the required ignition timing. Note that the spark plug 105 may be ignited at a timing (retard angle) later than the required ignition timing, and in this way, knocking or the like can be appropriately prevented.

The ignition coil 106 generates a predetermined current according to the required ignition timing output from the required ignition timing calculation unit 804, and the ignition plug 105 is ignited by this current.

[Fuel injection control process]
Next, fuel injection control processing by the ECU 108 will be described.

FIG. 10 is a flowchart for explaining fuel injection control processing by the ECU 108.

In step S101, the ECU 108 processes the operating conditions. Here, the driving conditions include acceleration travel from an idle state of a vehicle (not shown), deceleration travel from acceleration travel, steady travel maintaining a constant engine speed, driver's accelerator operation, It refers to conditions including environmental changes in the engine 100 such as temperature, humidity, and altitude (air density decreases).

In step S102, the air amount calculation unit 801 of the ECU 108 is based on the air flow rate detected by the air flow meter 118, the position of the reference angle forming unit 220 of the intake camshaft 121 detected by the cam angle sensor 122, and the like. Then, the air amount Q1 in the cylinder at the present time (the estimated air amount in the state before the intake valve 102 is closed) is calculated.

In step S103, the required fuel injection amount calculation unit 802 of the ECU 108 is based on the operating conditions processed by the ECU 108 in step S101 and the air amount Q1 in the cylinder calculated by the air amount calculation unit 801 in step S102. To calculate the required fuel injection amount.

In step S104, the ECU 108 determines whether or not there is an interrupt from the cam angle sensor 122 that detects the rotation angle of the intake-side camshaft 121, and determines that there is an interrupt (step S104: YES), step S106. If it is determined that there is no interruption (step S104: NO), the process proceeds to step S105.

If there is no interruption from the cam angle sensor 122 in step S105, the ECU 108 controls the fuel injection valve 104 in accordance with the required fuel injection amount calculated in step S103, performs normal fuel injection by the fuel injection valve 104, The process ends.

In step S106, when there is an interruption from the cam angle sensor 122, the air amount calculation unit 801 of the ECU 108 determines the amount of air in the cylinder at the timing when the interruption from the cam angle sensor 122 occurs (closing timing of the intake valve 102). Q2 is calculated.

In step S107, the ECU 108 calculates the air amount Q1 in the cylinder calculated at a timing other than the detection timing of the reference angle forming unit 220 in step S102 and the detection timing of the reference angle forming unit 220 in step S106. A difference ΔQ (= Q2−Q1) from the air amount Q2 in the cylinder is calculated. The ECU 108 determines the air amount Q1 in the cylinder calculated at a timing other than the detection timing of the reference angle forming unit 220 in step S102 and the in-cylinder calculated in the detection timing of the reference angle forming unit 220 in step S106. A ratio Qt (= Q2 / Q1) with the air amount Q2 may be calculated.

In step S108, the ECU 108 needs additional fuel injection so that the air-fuel ratio of the engine 100 detected by the air-fuel ratio sensor 112 becomes a desired air-fuel ratio based on the air amount difference ΔQ calculated in step S107. It is determined whether or not.

When it is determined that additional fuel injection is necessary (step S108: YES), the ECU 108 performs interrupt fuel injection control in step S109. On the other hand, when it is determined that additional fuel injection is unnecessary (step S108: NO), the ECU 108 does not perform the interrupt fuel injection and ends the process as it is.

[Required ignition timing calculation processing]
Next, the required ignition timing calculation process by the ECU 108 will be described.

FIG. 11 is a flowchart for explaining the required ignition timing calculation by the ECU 108.

In step S201, the ECU 108 processes the operating conditions in the same manner as in step S101.

In step S202, the air amount calculation unit 801 of the ECU 108, similarly to step S102, detects the air flow rate detected by the air flow meter 118 and the reference angle forming unit 220 of the intake camshaft 121 detected by the cam angle sensor 122. Based on the position and the like, the current air amount Q1 in the cylinder is calculated.

In step S203, the required ignition timing calculation unit 804 of the ECU 108 determines the ignition plug 105 based on the operation conditions in step S201, the air amount Q1 in the cylinder calculated in step S202, the detection result of the crank angle sensor 114, and the like. Calculate the required ignition timing.

In step S204, the ECU 108 determines whether or not there is an interruption (detection of a reference angle) from the cam angle sensor 122 that detects the rotation angle of the intake camshaft 121, and determines that there is an interruption (step S204). : YES), the process proceeds to step S205, and if it is determined that there is no interruption (step S204: NO), the process ends.

In step S205, ignition control of the spark plug 105 is performed based on the required ignition timing calculated in step S203. Here, in step S205, the case where the ignition control of the spark plug 105 is performed at the detection timing of the reference angle forming unit 220 by the cam angle sensor 122 has been described as an example, but the detection of the reference angle forming unit 220 by the cam angle sensor 122 is described. The ignition control of the spark plug 105 may be performed after the timing (retard angle). For example, ignition control of the ignition plug 105 may be performed based on a detection signal of a desired crank angle sensor 114 after the detection timing of the reference angle forming unit 220 by the cam angle sensor 122.

FIG. 12 shows a comparison between the conventional air-fuel ratio control (method A) by the control device for the internal combustion engine and the air-fuel ratio control (method B) by the control device for the internal combustion engine to which the present invention is applied during the transient operation of the engine 100. It is a figure explaining a result.

As shown in FIG. 12, in the conventional method A, as shown in the upper part A-2 of the graph, the timing at which the amount of air in the cylinder is determined is different, and the variation of the variable valve timing mechanism 123 is affected. The accuracy of air-fuel ratio control with respect to the target air-fuel ratio was poor.

On the other hand, in the system B to which the present invention is applied, the amount of air in the cylinder is accurately obtained, so that control close to the target air-fuel ratio becomes possible. Thus, by applying the present invention, it becomes possible to accurately calculate the amount of air in the cylinder even when the engine 100 is in a transient operation state, and the accuracy of air-fuel ratio control with respect to the target air-fuel ratio is improved. be able to.

As described above, in the embodiment,
(1) Controlling an engine 100 (internal combustion engine) having

camshafts

121 and 209 that open and close the intake valve 102 and the exhaust valve 103, and

cam angle sensors

122 and 209a that detect rotation angles of the

camshafts

121 and 209. ECU 108 (control device for an internal combustion engine), and camshaft 121 has a reference angle forming unit 220 configured to be detected by cam angle sensor 122, and reference angle forming unit 220 includes at least an intake valve. The configuration is such that it is provided at an angular position corresponding to (matching) the valve closing timing 102.

With this configuration, the ECU 108 closes the intake valve 102 from the detection signal of the reference angle forming unit 220 by the cam angle sensor 122 (the intake valve 102 and the exhaust valve 103 are both closed, and the cylinder is closed). State) can be detected. Therefore, in the cylinder of engine 100, the internal air amount is determined at the closing timing of intake valve 102, and ECU 108 can accurately calculate the air amount in the cylinder.

(2) Further, an interruption occurs when it is determined that the fuel injection amount at least at the detection timing of the reference angle forming unit 220 (in the above-described embodiment, the valve closing position IVC of the intake valve 102) is less than the required fuel injection amount. An interrupt fuel injection calculation unit 803 that calculates the fuel injection amount is provided.

With this configuration, the interrupt fuel injection calculation unit 803 has the fuel injection amount calculated at the valve closing position IVC of the intake valve 102 smaller than the required fuel injection amount calculated based on the air amount and the control signal 307. When the determination is made, the interrupt fuel injection amount is calculated, so that the engine 100 can be maintained in an appropriate combustion state.

(3) Further, the required fuel injection amount is calculated based on the air amount in the cylinder calculated at the detection timing of the reference angle forming unit 220 (in the above-described embodiment, the valve closing position IVC of the intake valve 102). The required fuel injection amount calculation unit 802 is provided.

With this configuration, the required fuel injection amount calculation unit 802 calculates the required fuel injection amount based on the accurate air amount calculated in a state where the air amount in the cylinder is fixed. It can be calculated accurately.

(4) In addition, the interrupt fuel injection calculation unit 803 is configured to calculate the air amount Q2 in the cylinder (first value) calculated at the detection timing of the reference angle forming unit 220 (in the above-described embodiment, the valve closing position IVC of the intake valve 102). 1 air amount) and the difference or ratio between the air amount Q1 (second air amount) in the cylinder calculated at a timing different from the detection timing of the reference angle forming unit 220, the interrupt fuel injection amount It was set as the structure which determines the necessity of the calculation of this.

If comprised in this way, the interruption fuel injection calculating part 803 will calculate the air quantity Q2 calculated at the detection timing of the reference angle formation part 220, and the air quantity Q1 calculated at a timing different from the detection timing of the reference angle formation part 220. Since it is determined whether or not to calculate the interrupt fuel injection amount on the basis of the difference or the ratio, it is possible to appropriately determine whether or not additional fuel injection is necessary.

(5) Further, it has an ignition device (ignition plug 105 and ignition coil 106) that ignites the air-fuel mixture in the cylinder of the engine 100. The ignition device detects the reference angle forming unit 220 or the reference angle forming unit 220. The air-fuel mixture is ignited at a timing (retarding angle) later than the detection timing.

With this configuration, the ignition timing by the ignition device is retarded from the valve closing position IVC of the intake valve 102, so that knocking of the engine 100 can be prevented.

(6) Further, the reference angle forming part 220 is configured to be a protrusion provided to protrude radially outward from the outer periphery of the cam rotor 208 having a disk shape provided on the outer periphery of the camshaft 121.

With this configuration, an existing cam angle sensor used in a general vehicle can be used, and an additional sensor or device for detecting the reference angle forming unit 220 is not necessary. Therefore, almost no additional cost for detecting the reference angle forming unit 220 is required.

(7) Further, the reference angle forming part 220 is configured to be a groove 220A or a hole provided so as to protrude radially inward from the outer periphery of the cam rotor 208 having a disk shape provided on the outer periphery of the camshaft 121.

Even with this configuration, the groove 220A or the hole can be detected by the cam angle sensor 122, and the reference angle of the camshaft 121 can be reliably detected.

(8) Further, the reference angle forming unit 220 is configured to be provided at angular positions corresponding to the intake stroke, compression stroke, explosion stroke, and exhaust stroke of the engine 100.

With this configuration, the ECU 108 can determine whether the intake stroke, the compression stroke, the explosion stroke, or the exhaust stroke is based on the detection timing of each reference angle forming unit 220, and the air in the intake stroke In addition to the accurate calculation of the amount, the fuel injection valve and the ignition device can be controlled at an appropriate timing.

[Second Embodiment]
Next, a control device for an internal combustion engine according to a second embodiment of the present invention will be described.
In the control apparatus for an internal combustion engine according to the second embodiment, the detection timing of the reference angle forming unit 220 by the

cam angle sensors

122 and 209a is determined based on the intake valve opening position IVO (Intake Valve Open) and the exhaust valve opening. The point of being configured to correspond to the valve position EVO (Exhaust Valve Open) or the valve closing position EVC (Exhaust Valve Close) is different from the above-described embodiment.

FIG. 13 is a diagram illustrating the detection timing of the reference angle forming unit 220 by the

cam angle sensors

122 and 209a according to the second embodiment. In addition, the same code | symbol is attached | subjected about the structure similar to embodiment mentioned above, and it demonstrates as needed.

As shown in FIG. 13, in the control apparatus for an internal combustion engine according to the second embodiment, the detection timing of the reference angle forming unit 220 by the

cam angle sensors

122 and 209a is not only the valve closing position IVC of the intake valve 102. The valve opening position IVO of the intake valve 102, the valve closing position EVC of the exhaust valve 103, and the valve opening position EVO are set to angular positions corresponding to all or all timings. That is, in the control device (ECU 108) for the internal combustion engine of the second embodiment, the reference angle forming portion 220 (protrusion) of the cam rotor 208 is the valve closing timing (valve closing position IVC) or valve opening timing (opening) of the intake valve 102. Valve position IVO), or a position corresponding to at least one of valve closing timing (valve closing position EVC) or valve opening timing (valve opening position EVO) of exhaust valve 103.

As a result, the control device (ECU 108) for the internal combustion engine can detect the opening / closing timings of all of the intake valves 102 and the exhaust valves 103. Therefore, the closing timings of the intake valves 102 and the exhaust valves 103 are closed. By detecting both of these, the amount of air in the cylinder can be determined more reliably.

As explained above, in the second embodiment,
(9) Control engine 100 (internal combustion engine) having

camshafts

121 and 209 that open and close intake valve 102 and exhaust valve 103, and

cam angle sensors

122 and 209a that detect rotation angles of

camshafts

121 and 209. The ECU 108 (control device for an internal combustion engine), and the

camshafts

121 and 209 have a reference angle forming unit 220 configured to be detected by

cam angle sensors

122 and 209a. , At least one of valve closing timing (valve closing position IVC) or valve opening timing (valve opening position IVO) of the intake valve 102, valve closing timing (valve closing position EVC) or valve opening timing (EVO) of the exhaust valve 103 It was set as the structure provided in the angular position corresponding to this timing.

With this configuration, the ECU 108 can detect the valve closing position IVC and the valve opening position IVO of the intake valve 102 and the valve closing position EVC and the valve opening position EVO of the exhaust valve 103, so that the amount of air in the cylinder Can be detected more accurately. Therefore, the ECU 108 can calculate the amount of air in the cylinder more accurately based on these detection timings.

[Third Embodiment]
Next, a control device for an internal combustion engine according to a third embodiment of the present invention will be described.
In the control apparatus for an internal combustion engine according to the third embodiment, the detection timing of the reference angle forming unit 220 by the

cam angle sensors

122 and 209a is set to the valve opening position IVO of the intake valve and the valve closing position EVC of the exhaust valve. The point which is comprised so that it may correspond differs from embodiment mentioned above.

FIG. 14 is a diagram illustrating the detection timing of the reference angle forming unit 220 by the

cam angle sensors

122 and 209a according to the third embodiment. In addition, the same code | symbol is attached | subjected about the structure similar to embodiment mentioned above, and it demonstrates as needed.

As shown in FIG. 14, in the control apparatus for an internal combustion engine according to the third embodiment,

cam angle sensors

122 and 209a are provided on the intake camshaft 121 and the exhaust camshaft 209, respectively. The detection timing of the cam angle sensor 122 provided on the intake side camshaft 121 coincides with the valve opening position IVO of the intake valve 102, and the cam angle sensor 209a provided on the exhaust side camshaft 209 closes the exhaust valve 103. The configuration matches the valve position EVC. That is, in the control device (ECU1) for the internal combustion engine according to the third embodiment, the reference angle forming unit 220 is provided at an angular position corresponding to the valve opening timing (the valve opening position IVO) of the intake valve 102. At the same time, it is provided at an angular position corresponding to the valve closing timing (EVC) of the exhaust valve 103.

By configuring the detection timing of the reference angle forming unit 220 by the

cam angle sensors

122 and 209a to coincide with the valve opening position IVO of the intake valve 102 and the valve closing position EVC of the exhaust valve 103, respectively, the intake valve 102 and the exhaust gas are exhausted. The overlap period during which both valves 103 are open can be calculated. Therefore, the ECU 108 can accurately calculate the internal EGR amount that takes in the exhaust gas burned in the engine 100 into the cylinder because the intake valve 102 and the exhaust valve 103 are simultaneously opened.

As a result, the ECU 108 can accurately calculate the internal EGR amount of the engine 100 without performing complicated calculation and correction control, and can perform optimum combustion control with high accuracy according to the internal EGR amount. .

As explained above, in the third embodiment,
(10) The reference angle forming unit 220 is provided at an angular position corresponding to the valve opening timing (valve opening position IVO) of the intake valve 102, and corresponds to the valve closing timing (valve closing position EVC) of the exhaust valve 103. It was set as the structure provided in the angle position to do.

With this configuration, the ECU 108 can detect an overlap period between the exhaust stroke and the intake stroke of the engine 100, and based on this overlap period, the variable valve timing mechanism 123 causes the intake valve 102 or the exhaust valve 103 to be detected. The combustion state of engine 100 can be appropriately controlled by adjusting the operating angle.

In the above, an example of the embodiment of the present invention has been described. However, the present invention may combine all of the above-described embodiments, and may arbitrarily combine any two or more embodiments.

Further, the present invention is not limited to the one having all the configurations of the above-described embodiment, and a part of the configuration of the above-described embodiment is replaced with the configuration of another embodiment. In addition, the configuration of the above-described embodiment may be replaced with the configuration of another embodiment.

Further, a part of the configuration of the above-described embodiment may be added to, deleted from, or replaced with the configuration of another embodiment.

100: engine, 101: piston, 102: intake valve, 103: exhaust valve, 104: fuel injection valve, 105: ignition plug, 106: ignition coil, 107: knock sensor, 108: ECU, 110: exhaust pipe, 111: Three-way catalyst, 112: air-fuel ratio sensor, 114: crank angle sensor, 116: crankshaft, 117: throttle valve, 118: air flow meter, 119: combustion chamber, 120: accelerator angle sensor, 121: intake side camshaft, 122: Cam angle sensor, 123: Variable valve timing mechanism, 201: Cam, 202: Phase variable cam pulley, 203: Cam pulley, 204: Crank pulley, 205: Oil pump, 206: Timing belt, 207: Oil control valve, 208: Cam rotor, 220A: groove, 209: intake air Cam shaft, 209a: Cam angle sensor, 210: Cam, 220: Reference angle forming part, 251: Cam housing, 252: Vane, 253: Advance chamber, 254: Delay chamber, 255: Solenoid, 256: Plunger, 257 : Housing, 258: spool, 259: spring, 260: drain port, 261: hydraulic pressure supply port, 262: advance angle port, 263: retard angle port, 280: oil passage, 281: phase advance hydraulic passage, 282: phase Retarded hydraulic passage, 300: input signal, 301: input circuit, 302: A / D converter, 303: CPU, 304: ROM, 305: RAM, 306: output circuit, 307: control signal

Claims

A control device for an internal combustion engine that controls an internal combustion engine having a cam shaft that opens and closes an intake valve and an exhaust valve, and a cam angle sensor that detects a rotation angle of the cam shaft,
The camshaft has a reference angle forming portion configured to be detected by the cam angle sensor;
The control apparatus for an internal combustion engine, wherein the reference angle forming unit is provided at an angular position corresponding to at least a valve closing timing of the intake valve.
2. The internal combustion engine according to claim 1, further comprising an interrupt injection calculation unit that calculates an interrupt fuel injection amount when it is determined that at least the fuel injection amount at the detection timing of the reference angle forming unit is less than the required fuel injection amount. Control device.
The control apparatus for an internal combustion engine according to claim 2, further comprising a required fuel injection amount calculation unit that calculates the required fuel injection amount based on an air amount in a cylinder calculated at a detection timing of the reference angle forming unit.
The interrupt injection calculating unit is configured to calculate the first air amount in the cylinder calculated at the detection timing of the reference angle forming unit and the first air amount in the cylinder calculated at a timing different from the detection timing of the reference angle forming unit. The control device for an internal combustion engine according to claim 3, wherein whether or not the calculation of the interrupt fuel injection amount is necessary is determined based on either a difference or a ratio with the two air amounts.
An ignition device for igniting an air-fuel mixture in the cylinder of the internal combustion engine;
The control device for an internal combustion engine according to claim 4, wherein the ignition device ignites the air-fuel mixture at a detection timing of the reference angle forming unit or a timing later than a detection timing of the reference angle forming unit.
A control device for an internal combustion engine that controls an internal combustion engine having a cam shaft that opens and closes an intake valve and an exhaust valve, and a cam angle sensor that detects a rotation angle of the cam shaft,
The camshaft has a reference angle forming portion configured to be detected by the cam angle sensor;
The reference angle forming unit is an internal combustion engine provided at an angular position corresponding to at least one of the closing timing or opening timing of the intake valve or the closing timing or opening timing of the exhaust valve. Control device.
The internal combustion engine according to claim 6, wherein the reference angle forming unit is provided at an angular position corresponding to a valve opening timing of the intake valve and is provided at an angular position corresponding to a valve closing timing of the exhaust valve. Engine control device.
The reference angle forming unit is
2. The control device for an internal combustion engine according to claim 1, wherein the control device is a protrusion provided to protrude radially outward from an outer periphery of a cam rotor having a disk shape provided on an outer periphery of the camshaft.
The reference angle forming unit is
2. The control device for an internal combustion engine according to claim 1, wherein the control device is a groove or a hole that is recessed radially inward from an outer periphery of a cam rotor having a disc shape provided on an outer periphery of the camshaft.
The internal combustion engine according to any one of claims 1 to 9, wherein the reference angle forming unit is provided at an angular position corresponding to an intake stroke, a compression stroke, an explosion stroke, and an exhaust stroke of the internal combustion engine. Control device.