JP3788269B2 - 4-stroke internal combustion engine stroke determination method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stroke determination method for determining a stroke of a four-cycle internal combustion engine and a stroke determination device used for carrying out the method.
[0002]
[Prior art]
As means for supplying fuel to the internal combustion engine, an injector (electromagnetic fuel injection valve), a fuel pump for supplying fuel to the injector, and an electronic controller (ECU) for generating an injection command signal at a predetermined fuel injection timing, A fuel injection device (EFI) including an injector drive circuit that supplies a drive current to the injector when an injection command signal is given is used.
[0003]
For example, when fuel is injected into an intake pipe of an engine using this fuel injection device, it is desirable to inject fuel near the intake stroke of the engine in order to efficiently send the injected fuel into the cylinder. In order to inject fuel in the vicinity of the intake stroke, it is necessary to detect the intake stroke, but in a four-cycle internal combustion engine, one combustion cycle is performed while the crankshaft rotates twice. It is not possible to determine the inhalation stroke only by detecting.
[0004]
Therefore, conventionally, a camshaft sensor that generates a reference signal having a pulse waveform only once per combustion cycle is attached to a camshaft that rotates once per combustion cycle, and position detection is performed every time the crankshaft rotates by a unit angle. Crank detected by each position detection pulse by attaching a crankshaft sensor that generates a pulse and specifying each position detection pulse generated by the crankshaft sensor with reference to a reference signal generated by the camshaft sensor It is determined which stroke the engine is in at the rotational angle position of the shaft.
[0005]
However, this method has a problem that the cost increases because it is necessary to attach sensors for generating pulse signals to both the crankshaft and the camshaft.
[0006]
Therefore, as disclosed in Japanese Patent Application Laid-Open No. 10-227252, a crankshaft sensor that generates a rotation angle detection pulse every time the crankshaft rotates by a predetermined angle is attached to the crankshaft, and an intake air corresponding to a specific cylinder. A pressure sensor for detecting pressure is provided, and the intake pressure detected when the crankshaft sensor generates a rotation angle detection pulse at a reference rotation angle position set at a specific rotation angle position is the same position before one rotation. A method for determining the stroke of a four-cycle internal combustion engine by comparing with the intake air pressure detected in step 1 was proposed.
[0007]
In this proposed detection method, for example, as shown in FIG. 7, there are seven reluctors r1 to r7 on the outer periphery, and an angular interval between one reluctator r1 and a reluctator r7 adjacent to the reluctor r1. Rotation angle detection pulses with different polarities are generated when the rotor Rt is set to twice the angular interval between the other relucters and the front and rear edges of the reluctators r1 to r7 are detected. A crankshaft sensor comprising a signal generator SG is provided, and the rotor Rt of the crankshaft sensor is attached to the crankshaft CS of the engine. When the signal generator SG detects the edge on the front end side of the reluctator r7 out of the series of rotation angle detection pulses P1 to P7 generated when the signal generator SG detects the edge on the front end side in the rotation direction of each of the reluctors r1 to r7. Using the fact that the interval between the generated pulse P7 and the pulse P1 generated when the front edge in the rotation direction of the next reluctator r1 is detected is larger than the generation interval of other pulses, the pulse P7 is set to the reference position. As shown in FIG. 6, pulse numbers 1 to 7 are assigned in order from the pulse next to the reference pulse P7. Furthermore, the rotor Rt and the signal generator SG are provided so that the generation position of a specific pulse, for example, the pulse of pulse number 3, coincides with the position corresponding to the top dead center of the piston of a specific cylinder of the engine.
[0008]
Further, a pressure sensor is attached to an intake pipe provided for a specific cylinder of the engine to detect a pressure (intake pressure) in the intake pipe. In a four-cycle internal combustion engine, the intake pressure changes, for example, as shown by curves a to c in FIG. In FIG. 6, curve a shows the change in the intake pressure of a specific cylinder when the engine is operating normally without sudden acceleration / deceleration with the throttle valve fully open. The rotation angle position is shown with respect to θ. Curve b shows the intake pressure of a specific cylinder when the engine is idling with the throttle valve returned to the fully closed position (position where the throttle valve opening is minimized), and curve c shows the throttle valve. A change with respect to the crank angle θ of the intake pressure of a specific cylinder when the engine is suddenly decelerated from the fully open state or a state close to the fully open state to the fully closed state at once is shown.
[0009]
In the proposed method, for example, the intake pressure of the curve b or c detected when the rotation angle detection pulse with the pulse number 3 is generated is detected at the generation position of the rotation angle detection pulse of the same number before one rotation. When the intake pressure detected this time is lower than the intake pressure detected one revolution before the intake pressure detected this time, it is generated approximately one revolution after the generation position of the pulse of the pulse number 4 generated thereafter. It is determined that the section up to the pulse generation position of the pulse number 3 is the section where the combustion stroke and the exhaust stroke are performed.
[0010]
[Problems to be solved by the invention]
According to the previously proposed method, it is not necessary to attach a camshaft sensor, and therefore it is possible to perform a stroke determination without causing an increase in cost. Further, when the intake pressure pulsation is small as shown by the curve b or c in FIG. 6, the stroke determination can be performed accurately.
[0011]
However, when the engine is operated in a state where the throttle valve is sufficiently opened and a large amount of air constantly flows into the intake pipe, the intake pressure pulsates finely due to the large amount of air flow as shown by curve a in FIG. Therefore, the difference between the intake pressure at the pulse generation position of the current pulse number 3 and the intake pressure at the pulse generation position of the pulse number 3 generated last time cannot be clearly identified, or the magnitude relationship of the intake pressure Since there is a reverse rotation, there has been a problem that it is not possible to accurately determine the stroke.
[0012]
An object of the present invention is to determine whether each one-rotation section of a four-cycle internal combustion engine is a section in which an intake stroke and a compression stroke are performed, or a section in which a combustion stroke and an exhaust stroke are performed without using a camshaft sensor. The object is to provide a determination method and a stroke determination apparatus used for carrying out the method.
[0013]
[Means for Solving the Problems]
In the stroke determination according to the present invention, the crankshaft of the four-cycle internal combustion engine is a specific cylinder (in the case of a single-cylinder internal combustion engine, the cylinder is any one cylinder in the case of a multi-cylinder internal combustion engine having two or more cylinders). A section that rotates once from a position corresponding to the top dead center of the piston is a determination target section, and each determination target section is a section in which a suction stroke and a compression stroke are performed in a specific cylinder, or a combustion stroke and an exhaust stroke are performed. This is a method for determining whether or not a section has been reached.
[0014]
The inventor pays attention to the fact that the minimum value always appears prominently in the intake pressure of the specific cylinder in the one rotation section in which the intake stroke and the compression stroke are performed in the specific cylinder. By detecting the value, a one-rotation interval in which the intake stroke and the compression stroke are performed and a one-rotation interval in which the combustion stroke and the exhaust stroke are performed are discriminated.
[0015]
Therefore, in the present invention, the intake pressure of the internal combustion engine is sampled at a predetermined sampling interval, the minimum value of the intake pressure corresponding to the specific cylinder sampled in each determination target section is obtained, and is obtained in each determination target section. Each determination target section is specified when the minimum value of the intake pressure corresponding to the specific cylinder is smaller than the minimum value of the intake pressure corresponding to the same cylinder obtained in the determination target section before each determination target section. It is determined that this is a section in which the intake stroke and the compression stroke are performed in the cylinder.
[0016]
In a four-cycle internal combustion engine, fine pulsation occurs in the intake pressure when the throttle valve is fully opened and the engine is operating, but even in this state, the intake pressure is significant in the section where the intake stroke and the compression stroke are performed. Minimum value appears. Therefore, if it is determined that the section where the minimum value appears in the intake pressure as described above is the section where the intake stroke and the compression stroke are performed, the engine stroke determination can be performed accurately.
[0017]
In a preferred aspect of the present invention, a rotation angle sensor that generates a rotation angle detection signal that includes information on a plurality of different rotation angle positions of a crankshaft of an internal combustion engine as information on a plurality of sampling positions, and specification of the crankshaft of the internal combustion engine A reference signal generator for generating a reference signal at a reference rotation angle position set at a rotation angle position of the engine, and detecting a plurality of sampling positions from the rotation angle detection signal to perform a process performed in a specific cylinder The intake pressure of the internal combustion engine that reflects this change is sampled every time each sampling position is detected. In addition, each determination target section is detected based on the reference signal, and the minimum of the intake pressure corresponding to a specific cylinder in each determination target section from a series of intake pressures sampled each time a plurality of sampling positions are detected. Find the value. And, when the minimum value in each determination target section of the intake pressure corresponding to a specific cylinder is smaller than the minimum value of the intake pressure of the same cylinder obtained in the determination target section immediately before each determination target section, Each determination target section is determined to be a section in which a suction stroke and a compression stroke are performed in a specific cylinder.
[0018]
As the rotation angle detection signal, for example, a sine waveform signal in which a zero cross point and positive and negative peak points appear many times during one rotation of the crankshaft, or a rectangular wave signal can be used.
[0019]
When a sine waveform signal is used as a rotation angle detection signal, each zero cross point or peak point is used as a sampling position. When a rectangular wave signal or a pulse waveform signal is used as the rotation angle detection signal, each rising or falling edge of the signal is set as a sampling position.
[0020]
In the above aspect, there is provided a rotation angle sensor that generates a rotation angle detection signal that includes a plurality of rotation angle positions of the crankshaft of the internal combustion engine as information on a plurality of sampling positions, and a change in stroke performed in a specific cylinder is provided. The reflected intake pressure of the internal combustion engine is sampled every time each sampling position is detected, but a sample timing signal generator that generates a sample timing signal at a predetermined period (time interval) is provided, and a specific timing is provided. The intake pressure reflecting the change in the stroke performed in the cylinder may be sampled every time the sample timing signal is generated (at a constant time interval).
[0021]
Further, the stroke determination apparatus according to the present invention uses a section in which the crankshaft of a four-cycle internal combustion engine makes one rotation from a position corresponding to the top dead center of a piston of a specific cylinder as a determination target section, and each determination target section has the specified specific section. A device for determining whether a cylinder is performing an intake stroke and a compression stroke, or a combustion stroke and an exhaust stroke, and in the present invention, information on a plurality of different rotation angle positions of a crankshaft of an internal combustion engine. A rotation angle sensor that generates a rotation angle detection signal that includes a plurality of sampling positions as information, and a reference signal generation that generates a reference signal at a reference rotation angle position set at a specific rotation angle position of the crankshaft of the internal combustion engine A determination target section detecting means for detecting each determination target section based on the generation position of the reference signal, and the plurality of sampling positions from the rotation angle detection signal. A sampling position detecting means for detecting the intake pressure, an intake pressure sampling means for sampling the intake pressure of the internal combustion engine in which a change in stroke performed in a specific cylinder is reflected each time the sampling position is detected, and an intake pressure sampling means Intake pressure minimum value calculating means for obtaining the minimum value in each judgment target section of the intake pressure corresponding to a specific cylinder from a series of sampled intake pressures, and the intake air corresponding to the specific cylinder obtained in each judgment target section When the minimum value of pressure is smaller than the minimum value of the intake pressure corresponding to the same cylinder obtained in the determination target section immediately before each determination target section, each determination target section is inhaled in the specific cylinder. And determination means for determining that the compression stroke has been performed.
[0022]
When a sinusoidal AC signal is used as the rotation angle detection signal, the sampling position detection means can be constituted by a zero cross detection circuit or a peak detection circuit. When a pulse waveform or rectangular wave signal is used as the rotation angle detection signal, the sampling position detection means can be configured by a differentiation circuit that differentiates each rising edge or each falling edge of the signal.
[0023]
In the above example, a plurality of different rotation angle positions of the crankshaft are used as sampling positions, respectively, but the rotation angle sensor is replaced with a sample timing signal generator that generates a sample timing signal at a constant cycle, The intake pressure sampling means may be configured to sample the intake pressure reflecting the stroke change performed in a specific cylinder every time the sample timing signal is generated.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0025]
FIG. 1 is a configuration diagram showing a configuration example of a system for controlling an internal combustion engine by an ECU. The illustrated internal combustion engine 1 is a single-cylinder four-cycle engine, and includes a cylinder 1a, a piston 1b, a crankshaft 1c connected to the piston 1b via a connecting rod, a cylinder head 1f having an intake port 1d and an exhaust port 1e. The intake valve 1g and the exhaust valve 1h for opening and closing the intake port and the exhaust port, the cam shaft 1i driven by the crankshaft 1c, and the valves for driving the intake valve 1g and the exhaust valve 1h as the cam shaft 1i rotates. A drive mechanism 1j and an intake pipe 1k connected to the intake port 1d are provided, and a throttle valve 1m is provided in the intake pipe 1k.
[0026]
A spark plug 2 is attached to the cylinder head of the internal combustion engine 1, and the spark plug 2 is connected to a secondary coil of the ignition coil IG through a high-voltage cord.
[0027]
An injector (electromagnetic fuel injection valve) 3 is attached to the intake pipe 1k of the internal combustion engine. The illustrated injector 3 has an injector body having a fuel injection port at the front end and a fuel supply port near the rear end, a position (open position) for opening the fuel injection port, and a position (closed position) for opening the fuel injection port in the injector body. And a solenoid for driving the valve member to the open position side, a biasing means for biasing the valve member to the normally closed position side, and a solenoid for driving the valve member to the open position side. Therefore, while the drive current is applied to the solenoid, the fuel injection port is opened to inject fuel into the intake pipe of the internal combustion engine.
[0028]
4 is a fuel tank that stores fuel to be supplied to the engine, 5 is an electric fuel pump that supplies the fuel in the fuel tank 4 to the injector 3, and 6 is a pressure regulator connected to a pipe connected to the fuel supply port of the injector 3. It is a vessel. The pressure regulator 6 is adjusted so as to keep the fuel pressure substantially at the set value by returning a part of the fuel supplied from the fuel pump 5 to the fuel tank 4 when the fuel pressure applied to the injector 3 exceeds the set value. To do.
[0029]
As described above, since the fuel pressure applied to the injector 3 is kept substantially constant, the amount of fuel injected from the injector 3 (fuel injection amount) is determined by the time during which the injection port of the injector 3 is open. The time during which the injection port of the injector 3 is open is substantially determined by the time during which the drive current is applied to the injector. Therefore, when controlling the fuel injection amount, the fuel injection amount required by the engine is calculated according to various control conditions, the injection time required to obtain the injection amount is obtained, and the predetermined injection timing is determined. During the injection time calculated when detected, a drive current is applied to the injector to cause fuel injection.
[0030]
Reference numeral 7 denotes a magnet generator driven by an engine crankshaft 1c. The illustrated magnet generator includes a magnet rotor 7a attached to the crankshaft 1c and a stator 7b fixed to an engine case or the like. ing. The illustrated magnet rotor 7a is a well-known flywheel magnet rotor including a cup-shaped flywheel 7c attached to the crankshaft 1c and a plurality of permanent magnets 7d attached to the inner periphery of the flywheel. It has become. In the illustrated example, six permanent magnets 7d are attached to the inner periphery of the flywheel, and these permanent magnets are magnetized to 12 poles.
[0031]
The stator 7b includes a multipolar star-shaped iron core in which a large number of teeth are radially formed and a large number of power generation coils wound around the numerous teeth of the iron core. The magnetic pole part at the tip of each tooth part of the multipolar star-shaped core to be configured is opposed to the magnetic pole part of the magnet rotor 7a via a predetermined gap.
[0032]
8 is an ECU that controls the fuel injection amount from the injector and the ignition timing of the engine, and 9 is a battery that is charged through the regulator 10 by the output voltage Vb of the battery charging generator coil provided in the stator of the magnet generator 7. The output voltage of the battery 9 is applied to the power supply terminal of the electric fuel pump 5 and the power supply terminal of the ECU 8. A power supply circuit for adjusting the battery voltage to a constant voltage suitable for driving the microcomputer is provided in the ECU 8, and the power supply voltage is applied from the power supply circuit to the power supply terminal of the microcomputer.
[0033]
The ECU 8 receives outputs from various sensors that detect a control condition for controlling the amount of fuel injected from the injector 3 and a control condition for controlling the ignition timing of the engine.
[0034]
In the illustrated example, a pressure sensor 12 that detects the pressure in the intake pipe 1k as an intake pressure, an intake air temperature sensor 13 that detects the intake air temperature of the engine, and a water temperature sensor 14 that detects the temperature of cooling water of the engine are provided. The outputs of these sensors are input to the A / D input port of the ECU 8.
[0035]
Further, a pulser 15 that generates a pulse at a specific rotational angle position of the crankshaft is provided, and an output of this pulser is input to the ECU 8. The pulsar 15 generates a pulse by detecting the edge of the reluctator 7e formed of a protrusion or a recess formed on the outer periphery of the flywheel 7c. For example, the pulsar 15 has an iron core having a magnetic pole portion facing the reluctator 7e at the tip, The permanent magnet is magnetically coupled to the iron core and a signal coil wound around the iron core.
[0036]
The pulser 15 generates a pair of pulses having different polarities when detecting the front end edge in the rotation direction of the reluctator 7e and when detecting the rear end edge in the rotation direction of the reluctator 7e. The pulser 15 constitutes a reference signal generating means, and one of a pair of pulses generated by the pulser is used as a reference signal.
[0037]
Here, as shown in FIG. 3C, the pulser 15 generates a negative pulse Vp1 and a positive pulse Vp2 when detecting the front edge and the rear edge of the reluctator 7e, respectively. And Of these pulses Vp1 and Vp2, the negative pulse Vp1 is used as a reference signal, and the generation position of the pulse Vp1 (position where the pulse Vp1 reaches the threshold value) is set as the reference rotation angle position.
[0038]
When the ECU 8 recognizes that the reference signal Vp1 has been generated, the ECU 8 detects that the rotation angle position of the crankshaft of the engine matches the reference rotation angle position. Since the illustrated internal combustion engine is a four-cycle engine, the reference signal Vp1 is generated twice per combustion cycle.
[0039]
In the illustrated example, a power generation coil wound around one tooth portion of the stator core of the magnet generator 7 is used as the rotation angle sensor 16, and a sine waveform output from the power generation coil constituting the rotation angle sensor. Is input to the ECU 8 as a rotation angle detection signal.
[0040]
In the ECU 8, an injector driving circuit and a primary current control circuit for controlling the primary current of the ignition coil IG are provided. The injector 3 and the ignition are respectively connected to the output terminal of the injector driving circuit and the output terminal of the primary current control circuit. A primary coil of the coil IG is connected.
[0041]
The ECU 8 causes the microcomputer to execute a predetermined program so as to constitute various function realizing means necessary for controlling the primary current of the injector 3 and the ignition coil IG, as well as a pulsar (reference signal generator) 15, Together with the rotation angle sensor 16 and the pressure sensor 12, a stroke determination device for determining the stroke of the engine is configured.
[0042]
FIG. 2 is a block diagram showing the hardware configuration of the system shown in FIG. 1 and the configuration of function realizing means constituted by a microcomputer in the ECU 8 and a program executed by the microcomputer. .
[0043]
In FIG. 2, an injector drive circuit 801 and an ignition coil primary current control circuit 802 are provided as hardware circuits in the ECU 8. The sampling position detection means 804 includes a zero cross detection circuit that detects a zero cross point generated when the AC voltage (rotation angle detection signal) Vg generated by the rotation angle sensor 16 shifts from a negative half wave to a positive half wave. ing. Other function realizing means is realized by causing the microcomputer in the ECU 8 to execute a predetermined program.
[0044]
The process determination method and apparatus according to the present invention and the configuration of each unit in FIG. 2 will be described below.
[0045]
First, a process determination method and a process determination apparatus according to the present invention will be described.
[0046]
FIG. 3 shows an example of a change in the intake pressure PB of the four-cycle internal combustion engine with respect to the crank angle θ, the waveform of the rotation angle detection signal Vg output from the rotation angle sensor 16, and the waveform of the pulse signal generated by the reference signal generator 15. Is shown. In FIG. 3 (A), a curve a indicates the intake pressure detected by the pressure sensor 12 when the engine is operating with the throttle valve 1m of the engine being sufficiently opened, and a curve b closes the throttle valve. This shows the change in the intake pressure PB when the engine is idling (with the throttle valve opening being minimized). A curve c shows a change in the intake pressure PB when the throttle valve is suddenly closed from the fully opened state and the engine is suddenly decelerated.
[0047]
FIG. 3B shows the waveform of the rotation angle detection signal Vg generated by the rotation angle sensor 16 composed of a power generation coil provided in the magnet generator 7 driven by the crankshaft of the engine. ) Shows the waveforms of the pulses Vp1 and Vp2 generated by the reference signal generator 15.
[0048]
As already described, in this embodiment, the pulse signal Vp1 generated when the reference signal generator detects the front edge in the rotation direction of the reluctator 7e is used as the reference signal.
[0049]
Each zero cross point (hereinafter simply referred to as zero cross point) when the rotation angle detection signal generated by the rotation angle sensor 16 shifts from a negative half wave to a positive half wave is used as a sampling position for sampling the intake pressure. In this example, since the rotor of the magnet generator 7 has 12 poles, the rotation angle detection signal Vg is generated 6 cycles while the crankshaft makes one rotation, and the six zero cross points of the rotation angle detection signal are generated. Are used as sampling positions.
[0050]
In the illustrated example, the reference position θo, which is the generation position of the reference signal signal Vp1, is set to a position immediately before the rotation angle position of the crankshaft when the piston of the engine reaches top dead center, and the reference signal Vp1 is The reference signal generator 15 and the magnet generator 7 are provided so that the zero-cross point of the rotation angle detection signal Vg appearing immediately after the occurrence coincides with the rotation angle position of the crankshaft when the piston of the engine reaches the top dead center. It has been.
[0051]
In this embodiment, in order to identify each zero cross point (sampling position) of the rotation angle detection signal Vg, an identification number 0 is assigned to the zero cross point of the rotation angle detection signal Vg that appears immediately after the occurrence of the reference signal Vp1 is detected. In the following, identification numbers 1 to 5 are attached to zero cross points used as sampling positions. Thus, when an identification number is assigned to a series of zero cross points of the rotation angle detection signal, the crankshaft of the four-cycle internal combustion engine specifies a section from the zero cross point of each identification number 0 to the next zero cross point of identification number 0. It can be detected as a section (determination target section) that rotates once from a position corresponding to the top dead center of the cylinder piston.
[0052]
As can be seen from the curves a to c in FIG. 3A, a minimum value always appears in the intake pressure PB of the four-cycle internal combustion engine in a one-rotation section in which the intake stroke and the compression stroke are performed. In FIG. 3A, PBmin1 indicates the minimum value that appears when the throttle valve is fully opened and the intake pressure changes as shown by curve a, and PBmin2 and PBmin3 each indicate that the engine is idling. The minimum value of the intake pressure when the intake pressure shows a change like the curve b and when the engine is suddenly decelerated and the intake pressure shows the change like the curve c is shown.
[0053]
When the throttle valve is fully opened, a fine pulsation is seen in the intake pressure as shown by curve a in FIG. 3A. In this case as well, in the section of one rotation in which the intake stroke and the compression stroke are performed. The minimum value appears in the intake pressure.
[0054]
From this, it can be seen that in the four-cycle internal combustion engine, the determination target section where the minimum value in the intake pressure appears can be determined as the section where the intake stroke and the compression stroke are performed.
[0055]
Therefore, in the stroke determination method of the present invention, the rotation angle sensor 16 for generating the rotation angle detection signal Vg including information on a plurality of different rotation angle positions of the crankshaft of the internal combustion engine as information on the plurality of sampling positions, respectively, A reference signal generator 15 for generating a reference signal Vp1 at a reference rotation angle position set at a specific rotation angle position of the crankshaft is provided, and a plurality of sampling positions (in the illustrated example, from the rotation angle detection signal Vg). Zero cross points (numbered 0 to 5) are respectively detected, and the intake pressure of the internal combustion engine in which the change of the stroke performed in a specific cylinder is reflected is sampled every time each sampling position is detected. Further, each determination target section is detected based on the reference signal Vp1, and the minimum value in each determination target section of the intake pressure corresponding to a specific cylinder is obtained from a series of intake pressures sampled every time the sampling position is detected. . And, when the minimum value in each determination target section of the intake pressure corresponding to a specific cylinder is smaller than the minimum value of the intake pressure of the same cylinder obtained in the determination target section immediately before each determination target section, Each determination target section is determined to be a section in which a suction stroke and a compression stroke are performed in a specific cylinder.
[0056]
In the example shown in FIG. 2, the stroke determination device that implements the stroke determination method according to the present invention includes rotation information that includes information on a plurality of different rotation angle positions of a crankshaft of an internal combustion engine (not shown) as information on a plurality of sampling positions. A rotation angle sensor 16 for generating an angle detection signal, a reference signal generator (pulser) 15 for generating a reference signal Vp1 at a reference rotation angle position set at a specific rotation angle position of the crankshaft of the internal combustion engine, and a rotation angle Sampling position detection means 804 for detecting a plurality of sampling positions from the detection signal, determination target section detection means 805 for detecting each determination target section based on the generation position of the reference signal Vp1, and strokes performed in a specific cylinder An intake pressure sampler that samples the intake pressure of the internal combustion engine that reflects the change in each time a plurality of sampling positions are detected. Means 806, an intake pressure minimum value calculating means 807 for obtaining a minimum value in each determination target section of the intake pressure corresponding to a specific cylinder from a series of intake pressures sampled by the intake pressure sampling means 806, and a minimum value calculating means The minimum value storage means 808 for storing the minimum value of the intake pressure obtained by 807, and the minimum value of the intake pressure corresponding to the specific cylinder obtained in each determination target section are the previous one of each determination target section. The determination unit 809 determines that each determination target section is a section in which the intake stroke and the compression stroke are performed when the intake pressure corresponding to the same cylinder obtained in the determination target section is smaller than the minimum value. ing.
[0057]
As described above, the sampling position detection means 804 is composed of a zero cross detection circuit, detects a zero cross point when the rotation angle detection signal shifts from a negative half wave to a positive half wave, and at each zero cross point. Generate zero-cross detection pulse.
[0058]
The determination target section detection means 805 attaches an identification number 0 to the zero-cross detection pulse generated immediately after the reference signal Vp1 is generated, and assigns identification numbers 1 to 5 to a series of zero-cross detection pulses generated thereafter. As a result, a section from the zero cross point of each number 0 to the next zero cross point of the number 0 is detected as a determination target section.
[0059]
The intake pressure sampling means 806 samples the intake pressure Pb detected by the pressure sensor 12 at a plurality of sampling positions detected from the rotation angle detection signal output from the rotation angle sensor 16.
[0060]
The intake pressure minimum value calculation means 807 compares the intake pressure sampled sequentially in each determination target section, finds the minimum value in each determination target section, and stores the calculated minimum value in the minimum value storage means 808.
[0061]
The determination unit 809 compares the minimum value of the intake pressure obtained in the current determination target section with the minimum value of the intake pressure calculated in the previous determination target section and stored in the storage unit 808. When the minimum value of the intake pressure corresponding to a specific cylinder determined in the determination target section is smaller than the minimum value of the intake pressure corresponding to the same cylinder determined in the determination target section immediately before each determination target section In addition, each determination target section is determined to be a section in which a suction stroke and a compression stroke are performed in a specific cylinder.
[0062]
In the above example, the zero cross point when the rotation angle detection signal Vg shown in FIG. 3B shifts from the negative half wave to the positive half wave is set as the sampling position, but the rotation angle detection signal is positive half. A zero cross point when shifting from a wave to a negative half wave may be set as a sampling position, or all zero cross points may be set as sampling positions. Further, the rotation angle position detected by the positive and negative peak points of the rotation angle detection signal can be set as the sampling position, and both the zero cross point and the positive and negative peak points can be set as the sampling position. If both the zero-cross point and the peak point are set as sampling positions, the sampling interval can be shortened, so that the stroke determination can be made accurately by detecting the change in the intake pressure more finely.
[0063]
In the above example, the power generation coil in the magnet generator driven by the engine is used as the rotation angle sensor. However, the rotation angle sensor generates a signal including information on a plurality of rotation angle positions of the internal combustion engine. A signal generator that generates a pulse signal each time the internal combustion engine rotates by a predetermined angle can also be used. In this case, the intake pressure sampling means has at least one of the rotation angle position of the crankshaft corresponding to the rise of the pulse signal generated by the signal generator and the rotation angle position of the crankshaft corresponding to the fall of the pulse signal as the sampling position. The configuration is as follows.
[0064]
As a signal generator that generates a pulse every time the crankshaft rotates by a predetermined angle, for example, teeth of a ring gear attached to the outer periphery of a flywheel to mesh with a pinion gear driven by an engine starting motor Can be used to generate a pulse signal (gear sensor). Further, a rotary encoder generally used for detecting the rotation angle position of the rotating member can also be used as the rotation angle sensor.
[0065]
When an encoder is used as the rotation angle sensor, by generating both the rotation angle detection pulse and the reference pulse from the encoder, the encoder can serve as both the rotation angle sensor and the reference signal generator. In order to generate both the rotation angle detection pulse and the reference pulse from the encoder, for example, the generation interval of a series of pulses generated from the encoder every time the internal combustion engine rotates by a small angle is set to an equal angular interval. In this case, the ECU may recognize the pulses generated at step S4 as rotation angle detection pulses, and the pulses generated at unequal intervals may be recognized as reference pulses.
[0066]
The pulse width of a series of pulses generated from the encoder every time the internal combustion engine rotates by a small angle is different from other pulses, and a series of pulses with the same pulse width is recognized as a rotation angle detection pulse, and the pulse width However, a pulse different from other pulses may be recognized as a reference pulse.
[0067]
In the above example, the sampling intervals of the intake pressure are set to be equal intervals, but the sampling intervals of the intake pressure may be unequal intervals.
[0068]
Next, in the control system shown in FIG. 1 and FIG. 2, the function realizing means other than the acceleration / deceleration detecting means realized by the ECU 8 will be described. The rotational speed calculating means 803 detects the rotational speed of the internal combustion engine at each instant. The rotational speed calculating means calculates the rotational speed of the engine from the generation interval of pulses output from the pulser 15.
[0069]
The injection amount calculation means 810 outputs the outputs of various sensors such as the intake air temperature detected by the intake air temperature sensor 13, the engine coolant temperature detected by the water temperature sensor 14, and the engine rotation calculated by the rotation speed calculation means 803. The fuel injection amount is calculated for control conditions such as speed. When calculating the injection amount, still other conditions such as atmospheric pressure may be used as control conditions.
[0070]
The injection timing calculation means 811 rotates the crankshaft from the reference position θo to the rotation angle position corresponding to the injection timing at each rotation speed calculated by the rotation speed calculation means 803 (time to start fuel injection). Calculation is performed in the form of the time required to perform the operation, and the calculated injection timing is given to the injection command generating means 812.
[0071]
The injection command generation means 812 calculates the injection time required for injecting the amount of fuel calculated by the injection amount calculation means 810 from the injector, and based on the rotation angle information obtained from the output of the reference signal generator 15. Thus, when a predetermined injection timing calculated by the injection timing calculation means is detected, an injection command signal having a signal width corresponding to the calculated injection time is given to the injector drive circuit 801.
[0072]
The injector drive circuit 801 applies a drive current to the injector 3 while the injection command signal is generated, and injects fuel from the injector.
[0073]
The ignition timing calculation means 813 calculates the ignition timing of the internal combustion engine with respect to the rotation speed calculated by the rotation speed calculation means 803.
[0074]
The ignition command generation means 814 starts detection of the ignition timing calculated by the ignition timing calculation means when the pulser 15 generates a specific pulse, for example, and when the calculated ignition timing of the engine is detected, the ignition coil primary An ignition command signal is given to the current control circuit 802.
[0075]
The primary current control circuit 802 causes a sudden change in the primary current of the ignition coil IG when an ignition command signal is given, and induces a high voltage for ignition in the secondary coil of the ignition coil. Since the ignition high voltage is applied to the spark plug 2, a spark discharge is generated in the spark plug 2 and the engine is ignited.
[0076]
FIG. 4 shows an example of a program stroke determination routine algorithm to be executed by the microcomputer of the ECU 8 in order to configure the stroke determination apparatus shown in FIG.
[0077]
The stroke determination routine shown in FIG. 4 is executed at regular intervals. In this routine, first, in step 1, the intake pressure PB sampled this time is read, and in step 2, the sampling position (zero cross point) is read. It is determined whether or not the identification number N is 0. When the identification number N is not 0, the routine proceeds to step 3 where it is determined whether or not the intake pressure PB is smaller than the latest minimum value PBmin calculated so far. As a result, when it is determined that the intake pressure PB is not smaller than the latest minimum value PBmin, the routine returns to the main routine for calculating the rotational speed without doing anything. If it is determined at step 3 that the intake pressure PB is smaller than the latest minimum value PBmin, the routine proceeds to step 4 where the intake pressure PB sampled this time is set to the minimum value PBmin.
[0078]
When it is determined in step 2 that the identification number N is 0, the process proceeds to step 5 and the minimum value PBmin of the intake pressure in the immediately preceding determination target section and the minimum value PBmin of the intake pressure in the immediately previous determination target section. (B) is compared, and when PBmin <PBmin (B), the routine proceeds to step 6 and whether or not the stroke determination flag BAKU is 0 (this determination target section is the section of the suction stroke and the compression stroke) Whether or not the previous determination was made). As a result, when the stroke determination flag BAKU is 0 (when it is determined that the current determination target section is a section of the intake stroke and the compression stroke), the routine proceeds to step 7 and the stroke determination flag BAKU is set to 1. Thus, it is determined that the next determination target section is a section in which the combustion stroke and the exhaust stroke are performed. Next, in preparation for the next determination, in step 8, the minimum value PBmin of the intake pressure in the immediately preceding determination target section is set as the minimum value PBmin (B) of the intake pressure in the immediately previous determination target section, and the process returns to the main routine.
[0079]
When it is determined in step 6 that BAKU = 0 is not satisfied (when it is determined that BAKU = 1), the determination result is contradictory, and the process proceeds to step 8 because determination is impossible.
[0080]
When it is determined in step 5 that PBmin ≧ PBmin (B), the process proceeds to step 10 to determine whether or not PBmin> PBmin (B). As a result, it is determined that PBmin> PBmin (B). If YES, the routine proceeds to step 11, where it is determined whether or not the stroke determination flag BAKU is 1 (whether or not it is determined that the current determination target section is a combustion stroke and exhaust stroke section). As a result, when BAKU = 1 (when it is determined that the current determination target section is the combustion stroke and the exhaust stroke), the routine proceeds to step 12 where BAKU = 0 and the next determination target section is inhaled. After determining that it is a section of the stroke and the compression stroke, the process proceeds to step 8.
[0081]
If it is determined in step 10 that PBmin ≦ PBmin (B), and if it is determined in step 11 that BAKU = 0, the determination results are contradictory, and the process determination is impossible and the process proceeds to step 8.
[0082]
In the above example, a plurality of sampling positions are detected from the rotation angle detection signal by the process of assigning the identification number N in order from the zero cross point immediately after the generation of the reference signal Vp1 (not shown in FIG. 4). Sampling position detection means configured to sample the intake pressure of the internal combustion engine, which reflects the change in the stroke performed in a specific cylinder in step 1 of FIG. 4, every time a plurality of sampling positions are detected. Means are configured. Step 2 constitutes the determination target section detection means, and Steps 3 and 4 realize the intake pressure minimum value calculation means for calculating the minimum value of the intake pressure in each determination target section. Also, in steps 5 to 7 and steps 10 to 12, the minimum value of the intake pressure corresponding to the specific cylinder obtained in each determination target section is determined in the determination target section immediately before each determination target section. When the intake pressure corresponding to the same cylinder is smaller than the minimum value, it is determined that each determination target section is a section in which the intake stroke and the compression stroke are performed in the specific cylinder, and is obtained in each determination target section. Each determination target section when the minimum value of the intake pressure corresponding to the specific cylinder is larger than the minimum value of the intake pressure corresponding to the same cylinder obtained in the determination target section immediately before each determination target section The determination means is configured to determine that the combustion stroke and the exhaust stroke are performed in a specific cylinder.
[0083]
In the above example, the zero-cross point of the rotation angle detection signal detected immediately after the generation of the reference signal Vp1 is made coincident with the top dead center of the engine piston, but the generation position of the reference signal Vp1 is set above the engine piston. The section from the generation position of each reference signal Vp1 to the generation position of the next reference signal may be set as the determination target section in accordance with the dead point.
[0084]
In the above example, the zero cross point of the AC voltage waveform output from the rotation angle sensor 16 is used as the sampling position. However, as shown in FIG. 5B, a series of pulse signals generated by the oscillator at a constant cycle. May be used as the sample timing signal S to sample the intake pressure PB every time each sample timing signal is generated.
[0085]
FIG. 5A shows the change of the intake pressure with respect to the crank angle θ, and FIG. 5C shows the output signal waveform of the reference signal generator. FIG. 5D shows the determination result of the stroke.
[0086]
In the example shown in FIG. 5, the generation position of the pulse Vp2 generated when the reference signal generator detects the rear end edge in the rotation direction of the reluctator is set as the reference position, and the reference position is set as the top dead center of the engine piston. Match.
[0087]
In this way, when the timing for sampling the intake pressure is determined by the sample timing signal generated at a constant cycle, the sampling timing is different from the crankshaft, so the number of times of sampling in each determination target section is different. However, in the present invention, since the minimum value of the determination target section of 360 ° may be obtained, the difference in the number of samplings does not matter.
[0088]
As shown in FIG. 5, when the sampling timing is determined by a sample timing signal generated at a constant period, only the reference signal generator 15 is provided as a mechanical sensor, and the rotation angle sensor is unnecessary. Therefore, the configuration can be simplified. In the example shown in FIG. 1, it is not necessary to use the power generation coil in the magnet generator 7 as the rotation angle sensor 16, so that the load that can be driven by the magnet generator 7 can be increased. Further, when the loads driven by the magnet generator 7 are the same, the magnet generator can be miniaturized.
[0089]
In the example shown in FIG. 1, the pressure sensor 12 is provided in the vicinity of the throttle valve 1m. However, when the intake pipe is provided with a surge tank that absorbs fluctuations in the intake pressure, in the vicinity of the throttle valve 1m. It is preferable to detect the intake pressure at a portion between the surge tank and the intake port of the engine because a pressure fluctuation accompanying a change in the engine stroke hardly appears in the detected intake pressure.
[0090]
In the above example, a single-cylinder internal combustion engine is taken as an example. However, in the case of a multi-cylinder internal combustion engine, by obtaining the minimum value of the intake pressure reflecting the stroke change of a specific cylinder, The stroke may be determined, and the strokes of the other cylinders may be determined from a mechanical angle shift with respect to a stroke change in a specific cylinder.
[0091]
In a multi-cylinder internal combustion engine, when an intake pipe is provided independently for each cylinder, the stroke performed in a specific cylinder is detected by detecting the pressure in the intake pipe provided for the specific cylinder. The intake pressure that reflects the change can be detected.
[0092]
In a multi-cylinder internal combustion engine, when the intake pipes of a plurality of cylinders are connected together into one intake pipe, the intake pressure is detected in the vicinity of the intake port of the specific cylinder. It is possible to detect the intake pressure reflecting the change in the stroke.
[0093]
【The invention's effect】
As described above, according to the present invention, the minimum value of the intake pressure in each determination target section is obtained, and the minimum value of the intake pressure obtained in each determination target section is obtained in the previous determination target section. When the intake pressure is smaller than the minimum value of the intake pressure, it is determined that each determination target section is a section where the intake stroke and the compression stroke are performed. Therefore, as in the case where the throttle valve is fully opened, the intake pressure The stroke determination can be performed even when the engine pulsates finely, and there is an advantage that the stroke determination can be accurately performed regardless of the operating state of the engine.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a configuration example of a system for controlling an internal combustion engine by an ECU.
FIG. 2 is a block diagram showing the configuration of a system showing a process determination apparatus according to the present invention.
FIG. 3 is a diagram showing a change in intake pressure of the internal combustion engine detected in the embodiment of the present invention, a waveform of a rotation angle detection signal, and a waveform of a reference signal together with a determination result of a stroke.
4 is a flowchart showing an example of an algorithm of a program executed by a microcomputer of an ECU in order to constitute a stroke determination device in the system shown in FIG.
FIG. 5 is a line showing a change in intake pressure detected in another embodiment of the present invention, a waveform of a sample timing signal that determines the sampling timing of the intake pressure, and a waveform of a reference signal together with a determination result of a stroke; FIG.
FIG. 6 is a diagram for explaining a conventional stroke determination method.
FIG. 7 is a configuration diagram showing a configuration of a signal generator used in a conventional stroke determination method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 4 cycle internal combustion engine, 2 ... Spark plug, 3 ... Injector, 7 ... Magnet generator, 8 ... ECU, 12 ... Pressure sensor, 15 ... Reference signal generator (pulser), 16 ... Rotation angle sensor (Magnet generator) Power generation coil).

Claims (5)

A section in which the crankshaft of a four-cycle internal combustion engine makes one rotation from a position corresponding to the top dead center of a piston of a specific cylinder is set as a determination target section, and each determination target section performs an intake stroke and a compression stroke in the specific cylinder. And a stroke determination method for determining whether a combustion stroke and an exhaust stroke are performed,
The intake pressure of the internal combustion engine that reflects the stroke change performed in the specific cylinder is sampled at a predetermined sampling interval, and the minimum value of the intake pressure corresponding to the specific cylinder sampled in each determination target section is obtained. Seeking
When the minimum value of the intake pressure corresponding to the specific cylinder determined in each determination target section is smaller than the minimum value of the intake pressure corresponding to the same cylinder determined in the determination target section before each determination target section In addition, the stroke determination method for a four-cycle internal combustion engine, wherein each determination target section is determined to be a section in which an intake stroke and a compression stroke are performed in the specific cylinder. A section in which the crankshaft of a four-cycle internal combustion engine makes one rotation from a position corresponding to the top dead center of a piston of a specific cylinder is set as a determination target section, and each determination target section performs an intake stroke and a compression stroke in the specific cylinder. It is a stroke determination method for determining whether it is a broken section or a section in which a combustion stroke and an exhaust stroke are performed,
A rotation angle sensor that generates a rotation angle detection signal that includes information on a plurality of different rotation angle positions of the crankshaft of the internal combustion engine as information on a plurality of sampling positions, A reference signal generator for generating a reference signal at a set reference rotation angle position;
Detecting each of the plurality of sampling positions from the rotation angle detection signal, sampling the intake pressure of the internal combustion engine in which a change in stroke performed in the specific cylinder is reflected, each time each sampling position is detected;
Detect each determination target section based on the reference signal,
Each determination target of the intake pressure corresponding to the specific cylinder is obtained by obtaining a minimum value in each determination target section of the intake pressure corresponding to the specific cylinder from a series of intake pressures sampled every time the sampling position is detected. When the minimum value in the section is smaller than the minimum value of the intake pressure of the same cylinder obtained in the determination target section immediately before each determination target section, each determination target section is suctioned and compressed in the specific cylinder. A stroke determination method for a four-cycle internal combustion engine, wherein the stroke is determined to be a section in which a stroke is performed. A section in which the crankshaft of a four-cycle internal combustion engine makes one rotation from a position corresponding to the top dead center of a piston of a specific cylinder is set as a determination target section, and each determination target section performs an intake stroke and a compression stroke in the specific cylinder. And a stroke determination method for determining whether a combustion stroke and an exhaust stroke are performed,
A sample timing signal generator for generating a sample timing signal at a constant period, and a reference signal generator for generating a reference signal at a reference rotation angle position set at a specific rotation angle position of the crankshaft of the internal combustion engine are provided. And
Sampling the intake pressure of the internal combustion engine reflecting the change in stroke performed in the specific cylinder every time each sample timing signal is generated,
Detect each determination target section based on the reference signal,
Obtaining a minimum value in each determination target section of the intake pressure corresponding to the specific cylinder from a series of intake pressures sampled each time the sample timing signal is generated;
When the minimum value in each determination target section of the intake pressure corresponding to the specific cylinder is smaller than the minimum value of the intake pressure corresponding to the same cylinder obtained in the determination target section immediately before each determination target section The method for determining a stroke of a four-cycle internal combustion engine, wherein each determination target section is determined to be a section in which an intake stroke and a compression stroke are performed in the specific cylinder. A section in which the crankshaft of a four-cycle internal combustion engine makes one rotation from a position corresponding to the top dead center of a piston of a specific cylinder is set as a determination target section, and each determination target section performs an intake stroke and a compression stroke in the specific cylinder. A stroke determination device for determining whether a combustion stroke and an exhaust stroke are performed,
A rotation angle sensor for generating a rotation angle detection signal including information on a plurality of different rotation angle positions of the crankshaft of the internal combustion engine as information on a plurality of sampling positions, respectively.
A reference signal generator for generating a reference signal at a reference rotation angle position set at a specific rotation angle position of the crankshaft of the internal combustion engine;
Determination target section detection means for detecting each determination target section based on the generation position of the reference signal;
Sampling position detection means for detecting each of the plurality of sampling positions from the rotation angle detection signal;
An intake pressure sampling means for sampling the intake pressure of the internal combustion engine in which a change in stroke performed in the specific cylinder is reflected, each time the plurality of sampling positions are detected;
An intake pressure minimum value calculating means for obtaining a minimum value in each determination target section of the intake pressure corresponding to the specific cylinder from a series of intake pressures sampled by the intake pressure sampling means;
The minimum value of the intake pressure corresponding to the specific cylinder determined in each determination target section is greater than the minimum value of the intake pressure corresponding to the same cylinder determined in the determination target section immediately before each determination target section. Determining means for determining that each determination target section is a section in which an intake stroke and a compression stroke are performed in the specific cylinder, when small;
A stroke determination apparatus for a four-cycle internal combustion engine, comprising: A section in which the crankshaft of a four-cycle internal combustion engine makes one rotation from a position corresponding to the top dead center of a piston of a specific cylinder is set as a determination target section, and each determination target section performs an intake stroke and a compression stroke in the specific cylinder. A stroke determination device for determining whether a combustion stroke and an exhaust stroke are performed,
A sample timing signal generator for generating a sample timing signal at a constant period; and
A reference signal generator for generating a reference signal at a reference rotation angle position set at a specific rotation angle position of the crankshaft of the internal combustion engine;
Determination target section detection means for detecting each determination target section based on the generation position of the reference signal;
An intake pressure sampling means for sampling the intake pressure of the internal combustion engine in which a change in stroke performed in the specific cylinder is reflected each time each sample timing signal is generated;
An intake pressure minimum value calculating means for obtaining a minimum value in each determination target section of the intake pressure corresponding to the specific cylinder from a series of intake pressures sampled by the intake pressure sampling means;
When the minimum value in each determination target section of the intake pressure corresponding to the specific cylinder is smaller than the minimum value of the intake pressure corresponding to the same cylinder obtained in the determination target section immediately before each determination target section Determining means for determining that each determination target section is a section in which an intake stroke and a compression stroke are performed in the specific cylinder;
A stroke determination apparatus for a four-cycle internal combustion engine, comprising:

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