JP2002339792A - Stroke determining method and device for 4-cycle internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stroke determining method capable of determining a stroke of a 4-cycle internal combustion engine without using a cam shaft sensor. SOLUTION: A section for one rotation from a position where a piston of the 4-cycle internal combustion engine 1 reaches a top dead center to the next top dead center is set as a subject section to determination. Output of a pressure sensor 12 to detect intake pressure of the internal combustion engine in which change of a stroke executed in a specified cylinder 1a in the internal combustion engine is reflected is sampled at a prescribed sampling interval. The minimum value of the intake pressure sampled in each subject section to determination is determined. When the minimum value of the intake pressure determined for each subject section to determination is smaller than the minimum value of the intake pressure determined for the preceding subject section to determination, the subject section to determination is determined to be a section where a suction stroke and a compression stroke were executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stroke determination method for determining a stroke of a four-stroke internal combustion engine and a stroke determination device used for executing the method.

[0002]

2. Description of the Related Art As means for supplying fuel to an internal combustion engine,
An injector (electromagnetic fuel injection valve), a fuel pump that supplies fuel to the injector, and an electronic controller (E) that generates an injection command signal at a predetermined fuel injection timing.
CU) and an injector driving circuit that supplies a driving current to the injector when an injection command signal is given.

When fuel is injected into, for example, an intake pipe of an engine using this fuel injection device, it is desirable to inject the fuel near the intake stroke of the engine in order to efficiently feed the injected fuel into a cylinder. . In order to inject fuel near the intake stroke, it is necessary to detect the intake stroke. However, in a four-stroke internal combustion engine, one combustion cycle is performed during two revolutions of the crankshaft. , The suction stroke cannot be determined.

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 each time the crankshaft rotates a unit angle. Attach a crankshaft sensor that generates a position detection pulse,
By specifying each position detection pulse generated by the crankshaft sensor with reference to a reference signal generated by the camshaft sensor, the engine can perform any stroke at the rotational angle position of the crankshaft detected by each position detection pulse. Was determined.

However, in this method, it is necessary to attach a sensor for generating a pulse signal to both the crankshaft and the camshaft, so that there is a problem that the cost is increased.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. Hei 10-227252, a crankshaft sensor that generates a rotation angle detection pulse every time the crankshaft rotates a predetermined angle is attached to the crankshaft, and the crankshaft sensor is mounted on a specific cylinder. A pressure sensor for detecting a corresponding intake 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 reduced by one rotation before. A method for determining the stroke of a four-stroke internal combustion engine by comparing the intake pressure detected at the same position with the intake pressure has been proposed.

In the proposed method, for example, FIG.
As shown in the figure, seven reluctors r1 to r7 are provided on the outer periphery, and the angular interval between one reluctor r1 and the reluctor r7 adjacent to the reductor r1 is twice the angular interval between the other reluctors. The rotor Rt set to
And a signal generator SG for generating a rotation angle detection pulse having a different polarity when detecting the front end side and the rear end side in the rotation direction of r7, respectively. Attach Rt to the crankshaft CS of the engine. A series of rotation angle detection pulses P1 to P1 generated when the signal generator SG detects the front edge of each of the reluctors r1 to r7 in the rotation direction.
7, the interval between the pulse P7 generated when the front edge of the reluctor r7 is detected and the pulse P1 generated when the front edge of the next reluctor r1 is detected in the rotational direction is determined by the generation of other pulses. The pulse P7 is specified as a reference pulse indicating the reference position by utilizing the fact that it is larger than the interval, and as shown in FIG. 6, pulse numbers 1 to 7 are assigned in order from the next pulse of 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 the specific cylinder of the engine.

A pressure sensor is attached to an intake pipe provided for a specific cylinder of the engine to detect a pressure in the intake pipe (intake pressure). 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, a curve a represents a change in the intake pressure of a specific cylinder when the engine is normally operated without sudden acceleration / deceleration with the throttle valve fully opened, and the change in the crank pressure (the crankshaft of the crankshaft). (Rotation angle position) 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 (the position where the throttle valve opening is minimized), and curve c shows the throttle valve The graph shows a change in the intake pressure of a specific cylinder with respect to the crank angle θ when the engine is suddenly decelerated from a fully opened state or a state close to the fully opened state to a fully closed state at a stretch.

In the proposed method, for example, the intake pressure of the curve b or c detected when the rotation angle detection pulse with pulse number 3 is generated is generated one rotation before the rotation angle detection pulse of the same number is generated. When the intake pressure detected this time is lower than the intake pressure detected one rotation before as compared with the intake pressure detected at the position, almost one rotation from the generation position of the pulse of pulse number 4 generated thereafter. It is determined that the section up to the position where the pulse of pulse number 3 that occurs later occurs is the section where the combustion stroke and the exhaust stroke are performed.

[0010]

According to the above-mentioned proposed method, it is not necessary to attach a camshaft sensor, so that the stroke can be determined without increasing the cost.
Further, when the pulsation of the intake pressure is small, as in the curve b or c in FIG. 6, the stroke determination can be accurately performed.

However, when the engine is operated with the throttle valve sufficiently opened and a large amount of air constantly flowing into the intake pipe, as shown by curve a in FIG. Due to the fine pulsation, the difference between the intake pressure at the position where the pulse of the current pulse number 3 is generated and the intake pressure at the position where the pulse of the previous pulse number 3 is generated cannot be clearly identified, or the intake pressure cannot be clearly identified. However, the magnitude relationship of the two may be reversed, so that there is a problem that the stroke determination cannot be performed accurately.

An object of the present invention is to determine whether a section of each rotation of a four-cycle internal combustion engine is a section where a suction stroke and a compression stroke are performed or a section where a combustion stroke and an exhaust stroke are performed without using a camshaft sensor. An object of the present invention is to provide a stroke determination method and a stroke determination device used for performing the method.

[0013]

According to the present invention, the stroke determination is performed when 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 thereof, or in the case of a multi-cylinder internal combustion engine having two or more cylinders). A section that makes one rotation from a position corresponding to the top dead center of the piston of any one of the predetermined cylinders) is determined as 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. This is a method for determining whether the section is a section where the combustion stroke and the exhaust stroke are performed.

The inventor of the present invention pays attention to the fact that a minimum value always appears remarkably in the intake pressure of a specific cylinder in one rotation section in which the intake stroke and the compression stroke are performed in the specific cylinder. By detecting the minimum value of the pressure, the section of one rotation in which the suction stroke and the compression stroke are performed and the section of one rotation in which the combustion stroke and the exhaust stroke are performed are determined.

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 determined, and the minimum value of the intake pressure corresponding to the specific cylinder determined in each determination target section is determined before the determination target section. When it is smaller than the minimum value of the intake pressure corresponding to the same cylinder obtained in the determination target section, it is determined that each determination target section is a section in which the intake stroke and the compression stroke are performed in a specific cylinder.

In a four-cycle internal combustion engine, when the throttle valve is sufficiently opened to operate the engine, fine pulsation occurs in the intake pressure. However, even in such a state, the intake pressure is not increased in the section where the intake stroke and the compression stroke are performed. A noticeable minimum in pressure appears. Therefore, if the section where the minimum value appears in the intake pressure as described above is determined to be the section where the intake stroke and the compression stroke are performed, the stroke determination of the engine can be performed accurately.

In a preferred aspect of the present invention, a rotation angle sensor for generating a rotation angle detection signal including 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 a crank for the internal combustion engine A reference signal generator that generates a reference signal at a reference rotation angle position set at a specific rotation angle position of the shaft is provided, and a plurality of sampling positions are respectively detected from the rotation angle detection signal, and a specific cylinder is used. The intake pressure of the internal combustion engine reflecting the change in the stroke to be performed is sampled every time each sampling position is detected. In addition, each determination target section is detected based on the reference signal, and from a series of intake pressures sampled each time a plurality of sampling positions are detected,
A minimum value of the intake pressure corresponding to a specific cylinder in each determination target section is obtained. When the minimum value of the intake pressure corresponding to the specific cylinder in each determination target 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, It is determined that each determination target section is a section where the intake stroke and the compression stroke have been performed in a specific cylinder.

As the rotation angle detection signal, for example, a signal having a sine waveform in which a zero cross point and positive and negative peak points appear many times during one rotation of the crankshaft, and a rectangular signal can be used.

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 signal or a pulse waveform signal is used as the rotation angle detection signal, each rising or falling edge of the signal is used as a sampling position.

In the above embodiment, a rotation angle sensor for generating a rotation angle detection signal including a plurality of rotation angle positions of the crankshaft of the internal combustion engine as information of a plurality of sampling positions is provided, and a stroke performed in a specific cylinder is provided. The intake pressure of the internal combustion engine in which the change of the internal combustion engine is reflected is sampled every time each sampling position is detected, but a sample timing signal generator for generating a sample timing signal at a predetermined cycle (time interval) is provided. Alternatively, the intake pressure reflecting a change in the stroke performed in a specific cylinder may be sampled (at a constant time interval) every time a sample timing signal is generated.

Further, the stroke determination device according to the present invention sets a section in which the crankshaft of the 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 sets each determination target section as a determination target section. An apparatus for determining whether a section in which the intake stroke and the compression stroke are performed in the specific cylinder or a section in which the combustion stroke and the exhaust stroke are performed. In the present invention, a plurality of different rotation angles of the crankshaft of the internal combustion engine are provided. A rotation angle sensor that generates a rotation angle detection signal that includes position information as information of a plurality of sampling positions, and a reference signal that is generated at a reference rotation angle position set at a specific rotation angle position of a crankshaft of an internal combustion engine. A reference signal generator;
The determination target section detection means for detecting each determination target section based on the generation position of the reference signal, the sampling position detection means for detecting each of the plurality of sampling positions from the rotation angle detection signal, and a specific cylinder. Intake pressure sampling means for sampling the intake pressure of the internal combustion engine reflecting the change of the stroke each time each sampling position is detected; and intake air corresponding to a specific cylinder from a series of intake pressures sampled by the intake pressure sampling means. An intake pressure minimum value calculating means for obtaining a minimum value in each determination target section of the pressure, and a minimum value of the intake pressure corresponding to the specific cylinder determined in each determination target section being one immediately before each determination target section. When the intake pressure corresponding to the same cylinder determined in the determination target section is smaller than the minimum value, And a determination unit intake and compression strokes in the cylinder is made a section is provided.

When a sine waveform 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-shaped or rectangular-wave-shaped signal is used as the rotation angle detection signal, the sampling position detection means can be constituted by a differentiating circuit for differentiating each rising or falling edge of the signal.

In the above example, a plurality of different rotation angle positions of the crankshaft are used as sampling positions. However, the rotation angle sensor is replaced by a sample timing signal generator that generates a sample timing signal at a constant cycle. Alternatively, the intake pressure sampling means may be configured to sample the intake pressure reflecting the change in the stroke performed in a specific cylinder every time a sample timing signal is generated.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An embodiment of the present invention will be described.

FIG. 1 is a block 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. , An intake valve 1g and an exhaust valve 1h for opening and closing an intake port and an exhaust port, respectively, and a camshaft 1 driven by a crankshaft 1c.
i, a valve drive mechanism 1j for driving the intake valve 1g and the exhaust valve 1h with the rotation of the camshaft 1i, and an intake pipe 1k connected to the intake port 1d. A valve 1m is provided.

An ignition plug 2 is attached to a cylinder head of the internal combustion engine 1, and the ignition plug 2
Is connected to the secondary coil through a high-voltage cord.

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 a front end and a fuel supply port near a rear end, and a position (open position) at which the fuel injection port is opened in the injector body.
A valve member provided so as to be displaceable between the valve member and a closing position (closed position), biasing means for constantly biasing the valve member to the closed position side, and a solenoid for driving the valve member to the open position side A fuel injection port is opened to inject fuel into an intake pipe of an internal combustion engine while a drive current is applied to a solenoid.

4 is a fuel tank for storing fuel to be supplied to the engine, 5 is an electric fuel pump for supplying the fuel in the fuel tank 4 to the injector 3, and 6 is connected to a pipe leading to a fuel supply port of the injector 3. Pressure regulator. The pressure regulator 6 adjusts the fuel pressure to be substantially maintained 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 given to the injector 3 exceeds the set value. I do.

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 reduced.
Is determined by the time during which the injection port is open. The time during which the injection port of the injector 3 is open is substantially determined by the time during which a drive current is applied to the injector. Therefore, when controlling the fuel injection amount, the fuel injection amount required by the engine is calculated in accordance with various control conditions, and the injection time required to obtain the injection amount is obtained. A drive current is supplied to the injector for the injection time calculated when the detection is made, and the fuel is injected.

Reference numeral 7 denotes a magnet generator driven by the crankshaft 1c of the engine.
And a stator 7b fixed to an engine case or the like. The illustrated magnet rotor 7a is composed of a well-known flywheel magnet rotor having 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. 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.

The stator 7b is composed of a multipolar star core having a large number of teeth formed radially, and a large number of power generating coils wound around the multiple teeth of the core. The magnetic pole portion at the tip of each tooth portion of the multipole star core constituting the rotor 7b is opposed to the magnetic pole portion of the magnet rotor 7a via a predetermined gap.

An ECU 8 controls the fuel injection amount from the injector and the ignition timing of the engine, and 9 is charged through a regulator 10 by an output voltage Vb of a battery charging generator coil provided on a stator of the magnet generator 7. The output voltage of the battery 9 is supplied to a power supply terminal of the electric fuel pump 5 and a power supply terminal of the ECU 8. EC
A power supply circuit for adjusting the voltage of the battery to a constant voltage suitable for driving the microcomputer is provided in U8, and the power supply voltage is applied from the power supply circuit to the power supply terminal of the microcomputer.

The outputs of various sensors for detecting the control conditions for controlling the amount of fuel injected from the injector 3 and the control conditions for controlling the ignition timing of the engine are input to the ECU 8.

In the illustrated example, the pressure sensor 12 detects the pressure in the intake pipe 1k as the intake pressure, the intake temperature sensor 13 detects the intake temperature of the engine, and the water temperature sensor 14 detects the temperature of the cooling water of the engine. The outputs of these sensors are input to the A / D input port of the ECU 8.

A pulser 15 for generating a pulse at a specific rotation angle position of the crankshaft is provided, and the output of the pulser is input to the ECU 8. Pulsa 15
A pulse is generated by detecting an edge of a reluctor 7e formed of a protrusion or a recess formed on the outer periphery of the flywheel 7c. For example, an iron core having a magnetic pole portion at the tip facing the reluctor 7e and a magnetic coupling to the iron core And a signal coil wound around the iron core.

The pulser 15 generates a pair of pulses having different polarities when detecting the leading edge in the rotational direction of the reluctor 7e and detecting the trailing edge in the rotational direction of the reluctor 7e. The pulsar 15 constitutes a reference signal generating means, and one of a pair of pulses generated by the pulsar is used as a reference signal.

Here, as shown in FIG. 3C, when the pulser 15 detects the front edge and the rear edge of the reluctor 7e, the pulse Vp1 of the negative polarity and the pulse Vp2 of the positive polarity are respectively transmitted. Shall occur. Of these pulses Vp1 and Vp2, the pulse Vp1 of negative polarity is used as a reference signal, and the position where the pulse Vp1 is generated (the position where the pulse Vp1 reaches a threshold value) is set as the reference rotation angle position.

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 coincides with 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.

In the example shown in the figure, a power generation coil wound around one tooth of the iron core of the stator of the magnet generator 7 is used as the rotation angle sensor 16, and the power generation coil constituting the rotation angle sensor outputs The sinusoidal AC voltage Vg is input to the ECU 8 as a rotation angle detection signal.

The ECU 8 is provided with an injector drive circuit and a primary current control circuit for controlling the primary current of the ignition coil IG. The output terminal of the injector drive circuit and the output terminal of the primary current control circuit are respectively connected to the injector. 3 and the primary coil of the ignition coil IG.

The ECU 8 causes the microcomputer to execute a predetermined program, thereby controlling the injector 3
In addition to configuring various functions necessary for controlling the primary current of the ignition coil IG, the process of determining the stroke of the engine together with the pulsar (reference signal generator) 15, the rotation angle sensor 16 and the pressure sensor 12 A determination device is configured.

FIG. 2 is a block diagram showing a hardware configuration of the system shown in FIG. 1 and a configuration of a function realizing means constituted by a microcomputer in the ECU 8 and a program executed by the microcomputer. Things.

In FIG. 2, the injector driving circuit 80
1 and the ignition coil primary current control circuit 802 are provided as a hardware circuit in the ECU 8. The sampling position detecting means 804 includes a zero-crossing detecting circuit for detecting a zero-crossing point generated when the AC voltage (rotational angle detection signal) Vg generated by the rotation angle sensor 16 shifts from a negative half-wave to a positive half-wave. ing. Other functions realizing means are realized by causing a microcomputer in the ECU 8 to execute a predetermined program.

Hereinafter, a method and an apparatus for judging the stroke according to the present invention and the configuration of each part in FIG. 2 will be described.

First, a stroke determination method and a stroke determination device according to the present invention will be described.

FIG. 3 shows the intake pressure PB of the four-cycle internal combustion engine.
Of the change with respect to the crank angle θ and the rotation angle sensor 1
6 shows the waveform of the rotation angle detection signal Vg output by the reference numeral 6 and the waveform of the pulse signal generated by the reference signal generator 15.
In FIG. 3A, a curve a indicates the intake pressure detected by the pressure sensor 12 when the engine is operated with the engine throttle valve 1m fully opened, and a curve b indicates that the throttle valve is closed. 3 shows the change in the intake pressure PB when the engine is idling (minimizing the throttle valve opening). A curve c shows a change in the intake pressure PB when the engine is suddenly decelerated by suddenly closing the throttle valve from the fully open state.

FIG. 3B shows a rotation angle detection signal Vg generated by a rotation angle sensor 16 composed of a generating coil provided in a magnet generator 7 driven by the crankshaft of the engine.
3C shows the waveforms of the pulses Vp1 and Vp2 generated by the reference signal generator 15. FIG.

As described above, in this embodiment, the pulse signal Vp1 generated when the reference signal generator detects the leading edge in the rotational direction of the reluctor 7e is used as the reference signal.

Each zero cross point (hereinafter simply referred to as a 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 set as a sampling position for sampling the intake pressure. Used.
In this example, since the rotor of the magnet generator 7 has 12 poles, the rotation angle detection signal Vg is generated in six cycles during one rotation of the crankshaft, and the six zero cross points of the rotation angle detection signal are generated. Are used as sampling positions.

In the illustrated example, the reference position θo, which is the position where the reference signal signal Vp1 is generated, is set to a position immediately before the rotation angle position of the crankshaft when the piston of the engine reaches the top dead center. The reference signal generator 15 and the magnet generator so that the zero cross point of the rotation angle detection signal Vg appearing immediately after the signal Vp1 is generated coincides with the rotation angle position of the crankshaft when the piston of the engine reaches the top dead center. 7 are provided.

In the present embodiment, in order to specify each zero-cross point (sampling position) of the rotation angle detection signal Vg, it is identified as a zero-cross point of the rotation angle detection signal Vg that appears immediately after the generation of the reference signal Vp1. Numbered 0,
In the following, the zero cross point used as the sampling position is 1 to
5 shall be assigned. When an identification number is assigned to a series of zero-cross points of the rotation angle detection signal in this manner, the section from the zero-cross point of each identification number 0 to the next zero-cross point of the identification number 0 has a specific crankshaft of the four-cycle internal combustion engine. It can be detected as a section (judgment section) that makes one rotation from a position corresponding to the top dead center of the cylinder piston.

As can be seen from the curves a to c in FIG. 3A, the minimum value of the intake pressure PB of the four-cycle internal combustion engine always appears in 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 sufficiently opened and the intake pressure changes as shown by curve a.
And PBmin3 are the minimum values of the intake pressure when the engine is idling and the intake pressure changes as shown by curve b, and when the engine is rapidly decelerated and the intake pressure changes as shown by curve c, respectively. Indicates the value.

When the throttle valve is fully opened, a fine pulsation is observed in the intake pressure as shown by a curve a in FIG. 3 (A). In this case, too, one rotation in which the intake stroke and the compression stroke are performed is performed. , The minimum value appears remarkably in the intake pressure.

From this, it can be seen that in the four-cycle internal combustion engine, the determination target section where the minimum value of the intake pressure appears can be determined to be the section where the intake stroke and the compression stroke have been performed.

Therefore, in the stroke determination method according to the present invention, a rotation angle sensor 16 for generating a rotation angle detection signal Vg including information on a plurality of different rotation angles of the crankshaft of the internal combustion engine as information on a plurality of sampling positions, respectively; A reference signal generator 1 that generates a reference signal Vp1 at a reference rotation angle position set at a specific rotation angle position of a crankshaft of an internal combustion engine.
5, a plurality of sampling positions (zero cross points numbered 0 to 5 in the illustrated example) are respectively detected from the rotation angle detection signal Vg, and a change in the stroke performed in a specific cylinder is reflected. The obtained intake pressure of the internal combustion engine is sampled every time each sampling position is detected. Further, each determination target section is detected based on the reference signal Vp1, and a 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 each time a sampling position is detected. . Then, the minimum value of the intake pressure corresponding to the specific cylinder in each determination target section is:
When the intake pressure of the same cylinder is smaller than the minimum value of the intake pressure of the same cylinder obtained in the immediately preceding determination target section of each determination target section, each determination target section is defined as a section in which a suction stroke and a compression stroke are performed in a specific cylinder. It is determined that there is.

In the example shown in FIG. 2, a stroke determination device for implementing the stroke determination method according to the present invention uses information on a plurality of different rotational 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 a rotation angle detection signal including a reference signal; a reference signal generator (pulsar) 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; Sampling position detecting means 804 for detecting a plurality of sampling positions from the rotation angle detection signal.
A determination target section detecting means 805 for detecting each determination target section based on the position where the reference signal Vp1 is generated; and a plurality of sampling positions at which the intake pressure of the internal combustion engine reflecting a change in a stroke performed in a specific cylinder is reflected. Pressure sampling means 806 for sampling each time is detected, and the intake pressure for obtaining the minimum value of the intake pressure corresponding to a specific cylinder in each determination target section from a series of intake pressures sampled by the intake pressure sampling means 806 Minimum value calculation means 807 and minimum value storage means 808 for storing the minimum value of the intake pressure determined by minimum value calculation means 807
And 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 immediately before each determination target section. Is smaller, the determination means 80 that determines that each determination target section is a section in which the suction stroke and the compression stroke have been performed.
9.

As described above, the sampling position detecting means 804 is composed of a zero cross detecting circuit, and detects a zero cross point when the rotation angle detection signal shifts from a negative half wave to a positive half wave, and detects each of the zero cross points. A zero-cross detection pulse is generated at the zero-cross point.

The determination target section detection means 805 assigns an identification number 0 to the zero-cross detection pulse generated immediately after the generation of the reference signal Vp1, and assigns an identification number 1 to 5 to a series of zero-cross detection pulses generated thereafter. Thereby, a section from the zero-cross point of each number 0 to the next zero-cross point of number 0 is detected as a determination target section.

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.

The intake pressure minimum value calculating means 807 compares the intake pressure sequentially sampled in each determination target section to obtain the minimum value in each determination target section, and stores the obtained minimum value in the minimum value storage means 808. Let it.

The determination means 809 compares the minimum value of the intake pressure obtained in the current determination target section with the minimum value of the intake pressure obtained in the immediately preceding determination target section and stored in the storage means 808. 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 immediately before each determination target section. Is smaller, it is determined that each determination target section is a section in which the intake stroke and the compression stroke are performed in a specific cylinder.

In the above example, the zero-cross point when the rotation angle detection signal Vg shown in FIG. 3B shifts from a negative half-wave to a positive half-wave is set as the sampling position. The zero-cross point at the transition from the positive half-wave to the negative half-wave may be set as the sampling position, or all the zero-cross points may be set as the sampling positions. The rotation angle position detected by the positive and negative peak points of the rotation angle detection signal can be used as the sampling position, and both the zero cross point and the positive and negative peak points can be used as the sampling position. If both the zero-cross point and the peak point are set as the sampling positions, the sampling interval can be shortened, so that the change of the intake pressure can be detected more finely and the stroke determination can be made accurately.

In the above-described example, the power generation coil in the magnet generator driven by the engine is used as the rotation angle sensor, but the rotation angle sensor generates a signal including information on a plurality of rotation angle positions of the internal combustion engine. Any signal generator may be used as long as it generates a pulse signal every time the internal combustion engine rotates by a predetermined angle. In this case, the intake pressure sampling means sets at least one of the rotation angle position of the crankshaft corresponding to the rising edge of the pulse signal generated by the signal generator and the rotation angle position of the crankshaft corresponding to the falling edge of the pulse signal as the sampling position. It is configured as follows.

As a signal generating device for generating a pulse every time the crankshaft rotates by a predetermined angle, for example, a ring attached to the outer periphery of a flywheel for meshing with a pinion gear driven by an engine starting motor is used. A device that detects a gear tooth and generates a pulse signal (gear sensor) can be used. Further, a rotary encoder generally used for detecting a rotation angle position of a rotating member can be used as the rotation angle sensor.

When an encoder is used as the rotation angle sensor, by generating both a rotation angle detection pulse and a reference pulse from the encoder, the encoder can be used as a rotation angle sensor and a 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 be partially unequal, In this case, the ECU may recognize the pulse generated at step (1) as a rotation angle detection pulse, and may recognize the pulse generated at irregular intervals as a reference pulse.

Also, the pulse width of a series of pulses generated by the encoder every time the internal combustion engine rotates by a minute angle is made different from other pulses, and a series of pulses having the same pulse width are recognized as a rotation angle detection pulse. Alternatively, a pulse having a pulse width different from other pulses may be recognized as a reference pulse.

In the above example, the sampling intervals of the intake pressure are made equal, but the sampling intervals of the intake pressure may be unequal.

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.
Numeral 3 is provided for detecting the rotation speed of the internal combustion engine at each moment. This rotation speed calculation means calculates the rotation speed of the engine from the generation interval of the pulse output from the pulser 15.

The injection amount calculating means 810 outputs the output of various sensors such as the intake air temperature detected by the intake air temperature sensor 13 and the engine cooling water temperature detected by the water temperature sensor 14.
The fuel injection amount is calculated based on control conditions such as the rotation speed of the engine calculated by the rotation speed calculation means 803. When calculating the injection amount, another condition such as the atmospheric pressure may be used as the control condition.

The injection timing calculating means 811 determines the injection timing (the timing at which fuel injection is started) at each rotational speed calculated by the rotational speed calculating means 803 from the reference position θo to the rotational angle corresponding to the injection timing. The calculation is performed in the form of the time required to rotate to the position, and the calculated injection timing is given to the injection command generation means 812.

The injection command generating means 812 calculates the injection time required for injecting the amount of fuel calculated by the injection amount calculating means 810 from the injector, and obtains the rotation angle obtained from the output of the reference signal generator 15. When a predetermined injection timing calculated by the injection timing calculation means is detected based on the information, an injection command signal having a signal width corresponding to the calculated injection time is given to the injector drive circuit 801.

The injector drive circuit 801 applies a drive current to the injector 3 while the injection command signal is being generated, and causes the injector to inject fuel.

The ignition timing calculation means 813 calculates the ignition timing of the internal combustion engine based on the rotation speed calculated by the rotation speed calculation means 803.

The ignition command generation means 814 starts detecting the ignition timing calculated by the ignition timing calculation means when the pulser 15 generates a specific pulse, for example, and detects the calculated ignition timing of the engine. An ignition command signal is given to the ignition coil primary current control circuit 802.

The primary current control circuit 802 causes a sudden change in the primary current of the ignition coil IG when the ignition command signal is given, and induces a high voltage for ignition in the secondary coil of the ignition coil. This ignition high voltage is applied to the spark plug 2
, A spark discharge occurs in the spark plug 2 and the engine is ignited.

FIG. 4 shows an example of an algorithm of a stroke judgment routine of a program executed by the microcomputer of the ECU 8 to configure the stroke judgment apparatus shown in FIG.
It was shown to.

The stroke determination routine shown in FIG. 4 is executed at regular intervals. In this routine, first in step 1, the intake pressure P
B is read, and it is determined in step 2 whether the identification number N of the sampling position (zero cross point) is 0 or not. If 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 process returns to the main routine for performing the calculation of the rotational speed without performing anything. When it is determined in step 3 that the intake pressure PB is smaller than the latest minimum value PBmin, the process proceeds to step 4 and the intake pressure PB sampled this time is set to the minimum value PBmin.

If it is determined in step 2 that the identification number N is 0, the process proceeds to step 5 where the minimum value PBmin of the intake pressure in the immediately preceding determination target section and the intake pressure in the immediately preceding determination target section are determined. Minimum value PBmin (B)
When PBmin <PBmin (B), the routine proceeds to step 6 and determines whether or not the stroke determination flag BAKU is 0 (determination that the current determination target section is the section of the suction stroke and the compression stroke). Is performed last time). As a result, when the stroke determination flag BAKU is 0 (when the current determination target section is determined to be the section of the suction stroke and the compression stroke), the process proceeds to step 7 and the stroke determination flag BAKU is set to 1 Then, it is determined that the next determination target section is a section in which the combustion stroke and the exhaust stroke are performed. Then, 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 preceding determination target section, and the process returns to the main routine.

If it is determined in step 6 that BAKU is not equal to 0 (determined that BAKU = 1), the results of the determination are inconsistent, and the process proceeds to step 8 with determination impossible.

In step 5, PBmin ≧ PBmin (B)
When it is determined that
It is determined whether or not Bmin> PBmin (B), and as a result,
When it is determined that PBmin> PBmin (B), the routine proceeds to step 11, where it is determined whether or not the stroke determination flag BAKU is 1 (when it is determined that the current determination target section is the section of the combustion stroke and the exhaust stroke). Is determined).
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 suctioned. After it is determined that the section is the section of the stroke and the compression stroke, the process proceeds to step 8.

In step 10, PBmin ≦ PBmin
When it is determined to be (B), and when it is determined that BAKU = 0 in step 11, the determination results are inconsistent, and the process proceeds to step 8 with the stroke determination impossible.

In the above example, a plurality of sampling positions are obtained from the rotation angle detection signal by a process (not shown in FIG. 4) of sequentially assigning identification numbers N from the zero-cross point immediately after the generation of the reference signal Vp1. Of the internal combustion engine reflecting the change of the stroke performed in the specific cylinder in step 1 of FIG. 4 each time a plurality of sampling positions are detected. An intake pressure sampling means is constituted. Step 2 constitutes a determination target section detection means, and steps 3 and 4 realize an intake pressure minimum value calculation means for calculating the minimum value of the intake pressure in each determination target section. Steps 5 to 7 and 10
According to the above, the minimum value of the intake pressure corresponding to the specific cylinder determined in each determination target section is determined as the minimum value of the intake pressure corresponding to the same cylinder determined in the immediately preceding determination target section of each determination target section. When it is smaller than the minimum value, each determination target section is determined to be a section in which the intake stroke and the compression stroke have been performed in the specific cylinder, and the intake pressure corresponding to the specific cylinder determined in each determination target section is determined. Is larger than the minimum value of the intake pressure corresponding to the same cylinder obtained in the immediately preceding determination target section of each determination target section, each determination target section is subjected to a combustion stroke and an exhaust A determining means for determining that the section has been performed is configured.

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 matched with the top dead center of 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 top dead center of the piston.

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. May be used as the sample timing signal S, and the intake pressure PB may be sampled each time each sample timing signal is generated.

FIG. 5A shows the change in 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 result of the stroke determination.

In the example shown in FIG. 5, the generation position of the pulse Vp2 generated when the reference signal generator detects the trailing edge of the rotational direction of the reluctor is set as the reference position, and the reference position is set above the piston of the engine. Matches to dead point.

As described above, when the timing for sampling the intake pressure is determined by the sample timing signal generated at a constant period, the sample timing signal is not synchronized with the crankshaft. May be different, but in the present invention, since the minimum value of the 360 ° determination target section only needs to be obtained, the difference in the number of times of sampling does not matter.

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 needs to be provided as a mechanical sensor. Is unnecessary, so that the configuration can be simplified. FIG.
In the example shown in (1), since there is no need to use the power generation coil in the magnet generator 7 as the rotation angle sensor 16, the load that can be driven by the magnet generator 7 can be increased.
When the load driven by the magnet generator 7 is the same, the size of the magnet generator can be reduced.

In the example shown in FIG. 1, the pressure sensor 12 is provided in the vicinity of the throttle valve 1m. However, when a surge tank for absorbing fluctuations in the intake pressure is provided in the intake pipe, the throttle valve 1m is provided. It is difficult for pressure fluctuations due to changes in the stroke of the engine to appear in the intake pressure detected near
It is preferable to detect the intake pressure at a portion between the surge tank and the intake port of the engine.

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, a specific value is obtained by obtaining the minimum value of the intake pressure reflecting the stroke change of one specific cylinder. The strokes of the cylinder may be determined, and the strokes of the other cylinders may be determined based on the deviation of the mechanical angle with respect to the change of the stroke in the specific cylinder.

In a multi-cylinder internal combustion engine, if an intake pipe is provided independently for each cylinder, the pressure in the intake pipe provided for the specific cylinder is detected, and the operation is performed in the specific cylinder. Thus, it is possible to detect the intake pressure on which the change in the stroke is reflected.

In a multi-cylinder internal combustion engine, when the intake pipes of a plurality of cylinders are collectively connected to one intake pipe, a specific intake cylinder is detected by detecting the intake pressure near the intake port of the specific cylinder. It is possible to detect the intake pressure reflecting the change in the stroke performed in the cylinder.

[0093]

As described above, according to the present invention, the minimum value of the intake pressure in each determination target section is determined, and the minimum value of the intake pressure determined in each determination target section is determined by the immediately preceding determination target. When the suction pressure is smaller than the minimum value of the intake pressure obtained in the section, each determination target section is determined to be a section in which the suction stroke and the compression stroke are performed, so that when the throttle valve is in the fully opened state. As described above, the stroke determination can be performed even when the intake pressure 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 illustrating a configuration example of a system that controls an internal combustion engine by an ECU.

FIG. 2 is a block diagram showing a configuration of a system showing a stroke determination device according to the present invention.

FIG. 3 is a diagram showing a change in intake pressure of an internal combustion engine detected in an embodiment of the present invention, a waveform of a rotation angle detection signal, and a waveform of a reference signal, together with a stroke determination result.

FIG. 4 is a flowchart illustrating an example of an algorithm of a program executed by a microcomputer of an ECU to configure the stroke determination device in the system illustrated in FIG. 1;

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 for determining a timing of sampling of the intake pressure, and a waveform of a reference signal together with a result of stroke determination. 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]

1 ... 4 cycle internal combustion engine, 2 ... Spark plug, 3 ... Injector, 7 ... Magnet generator, 8 ... ECU, 12 ... Pressure sensor, 15 ... Reference signal generator (pulsar), 16 ... Rotation angle sensor (Magnet generator) Power generation coil).

Claims (5)

[Claims] 1. A section in which a crankshaft of a four-cycle internal combustion engine makes one rotation from a position corresponding to a top dead center of a piston of a specific cylinder is set as a determination target section. A stroke determination method for determining whether a compression stroke is performed or a combustion stroke and an exhaust stroke are performed, wherein the intake pressure of the internal combustion engine, which reflects a change in stroke performed in the specific cylinder, is determined. Sampling is performed at a predetermined sampling interval, a minimum value of the intake pressure corresponding to the specific cylinder sampled in each determination target section is obtained, and an intake pressure corresponding to the specific cylinder obtained in each determination target section is obtained. When the minimum value 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, each determination target section is set in the specific cylinder in the intake stroke. Stroke determination method for a four-cycle internal combustion engine and determines that a section in which fine compression stroke is performed. 2. A section in which a 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 the section where the compression stroke was performed,
A method for determining a stroke in which a combustion stroke and an exhaust stroke are performed, comprising: a rotation angle detection signal including information on a plurality of different rotation angles of a crankshaft of the internal combustion engine as information on a plurality of sampling positions. A rotation angle sensor that generates a reference signal generator 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. Each of the plurality of sampling positions is detected, and the intake pressure of the internal combustion engine, which reflects a change in the stroke performed in the specific cylinder, is sampled every time each sampling position is detected, based on the reference signal. Corresponding to the specific cylinder from a series of intake pressures sampled each time the sampling position is detected. The minimum value in each determination target section of the intake pressure corresponding to the specific cylinder is obtained by calculating the minimum value of the intake pressure in each determination target section. And determining that each of the determination target sections is a section in which the intake stroke and the compression stroke have been performed in the specific cylinder when the intake pressure is smaller than the minimum value of the intake pressure of the four-stroke internal combustion engine. . 3. A section in which the crankshaft of the 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. What is claimed is: 1. A stroke determination method for determining whether a compression stroke is performed or a combustion stroke and an exhaust stroke are performed, comprising: a sample timing signal generator that generates a sample timing signal at a constant cycle; A reference signal generator that generates a reference signal at a reference rotation angle position set at a specific rotation angle position of the crankshaft, wherein the change in the stroke performed in the specific cylinder is reflected. The sampling pressure is sampled each time a sample timing signal is generated, each determination target section is detected based on the reference signal, and the sample timing signal is generated. The minimum value in each determination target section of the intake pressure corresponding to the specific cylinder is obtained from a series of intake pressures sampled each time, and the minimum value in each determination target section of the intake pressure corresponding to the specific cylinder is: When the intake pressure is smaller than the minimum value of the intake pressure corresponding to the same cylinder obtained in the immediately preceding determination target section of each determination target section, the suction stroke and the compression stroke of each determination target section are performed in the specific cylinder. A stroke determination method for a four-stroke internal combustion engine, wherein the stroke is determined to be a section where the stroke has occurred. 4. A section in which a 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 determined as a determination target section. A stroke judging device for judging whether a section where a compression stroke has been performed or a section where a combustion stroke and an exhaust stroke have been performed. A rotation angle sensor that generates a rotation angle detection signal including as position information, a reference signal generator 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 a reference signal generation position; and detecting each of the plurality of sampling positions from the rotation angle detection signal. Sampling position detection means; intake pressure sampling means for sampling the intake pressure of the internal combustion engine, in which the change in the stroke performed in the specific cylinder is reflected, each time the plurality of sampling positions are detected; Intake pressure minimum value calculating means for obtaining the minimum value of the intake pressure corresponding to the specific cylinder in each determination target section from a series of intake pressures sampled by the sampling means; and the specific cylinder determined in each determination target section When the minimum value of the intake pressure corresponding to is smaller than the minimum value of the intake pressure corresponding to the same cylinder obtained in the immediately preceding determination target section of each determination target section, Determining means for determining a section in which the intake stroke and the compression stroke have been performed in the cylinder; Institutions of stroke determination device. 5. A section in which a crankshaft of a four-cycle internal combustion engine makes one rotation from a position corresponding to a top dead center of a piston of a specific cylinder is determined as a determination target section. What is claimed is: 1. A stroke determination device for determining whether a compression stroke is performed or a combustion stroke and an exhaust stroke are performed, comprising: a sample timing signal generator that generates a sample timing signal at a constant cycle; A reference signal generator that generates a reference signal at a reference rotation angle position set at a specific rotation angle position of the crankshaft; and a determination target section detection that detects each determination target section based on the generation position of the reference signal. Means for sampling the intake pressure of the internal combustion engine reflecting the change in the stroke performed in the specific cylinder each time a sample timing signal is generated. Sampling means, 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, and the specific cylinder When the minimum value of the corresponding intake pressure in each determination target section is smaller than the minimum value of the intake pressure corresponding to the same cylinder obtained in the immediately preceding determination target section of each determination target section, each determination target section And a determining means for determining that the section is a section in which the suction stroke and the compression stroke have been performed in the specific cylinder.