The present invention relates to a rotational speed variation amount detecting device that detects a rotational speed variation amount of a multi-cylinder four-cycle engine, and an engine control device that performs control causing the rotational speed of the engine to converge on a target rotational speed while calculating a control gain using the rotational speed variation amount detected by the rotational speed variation amount detecting device.
An engine control device, which performs feedback control causing a rotational speed of an engine to converge on a target rotational speed, is provided with, as basic constituent elements, an operating part operated in order to adjust the rotational speed of the engine, a speed deviation calculation part that calculates a deviation between an actual rotational speed of the engine and the target rotational speed, a control gain setting part that sets a control gain, an operation amount calculation part that calculates an operation amount of the operating part needed to cause the rotational speed of the engine to converge on the target rotational speed using the deviation calculated by the speed deviation calculation part and the control gain set by the control gain setting part, and an operating part operation means that operates the operating part by the operation amount calculated by the operation amount calculation part, as is indicated in, for example, patent document 1.
In this type of control device, when the control gain has not been appropriately set, a problem is encountered in that rotational speed overshoot or undershoot occurs when the rotational speed of the engine changes due to load fluctuation, and it takes time for the rotational speed to converge on the target rotational speed. To have rotational speed control be quickly performed, the control gain must be set not to a fixed value but to an appropriate value in accordance with a degree of the rotational speed variation amount.
A widely used method of detecting a rotational speed of the engine is a method in which information on the rotational speed of the engine is obtained by generating an electrical signal having a prescribed waveform as a rotation signal with each rotation of a crankshaft of the engine, and measuring a time interval at which this rotation signal occurs. The rotation signal generated with each rotation of the crankshaft could be, for example, a pulse signal generated from a pulse generator (pick-up coil) attached to the engine, an ignition pulse induced in a primary coil of an ignition coil upon engine ignition, or a rectangle-wave signal or pulse signal indicating a level change when a specific portion (zero-cross point, peak point and the like) is detected in a waveform of AC voltage induced in a generating coil provided within an ignition unit in order to obtain ignition energy.
When the rotational speed is detected by the method described above, a rotational speed variation amount that has occurred while the crankshaft has rotated once can be detected as a degree of the rotational speed variation amount by taking a difference between a currently detected rotational speed and a previously detected rotational speed every time the rotation signals are generated, and a control gain can be set in accordance with the degree of the rotational speed variation amount of the engine by finding the control gain relative to this rotational speed variation amount through map calculation or another method.
With the method described above, the rotational speed variation amount is detected only once while the engine makes one rotation; therefore, when the load of the engine frequently fluctuates, there have been cases in which it is difficult to set the control gain precisely in accordance with the fluctuation in the rotational speed of the engine that accompanies the load fluctuation, and to perform control causing the rotational speed to quickly converge on the target rotational speed.
Particularly, in the case that the engine is a V-type two-cylinder engine in which a first cylinder and a second cylinder are disposed at an angular interval less than 180° (e.g., an angular interval of 90°), an angle of a range from an ignition position of the first cylinder to an ignition position of the second cylinder and an angle of a range from the ignition position of the second cylinder to the ignition position of the first cylinder are different. Therefore, a difference sometimes arises between the rotational speed variation amount occurring while the crankshaft rotates through the range from the ignition position of the first cylinder to the ignition position of the second cylinder and the rotational speed variation amount occurring while the crankshaft rotates through the range from the ignition position of the second cylinder to the ignition position of the first cylinder, but in cases of using the prior-art method in which the rotational speed variation amount of the engine is detected only once while the crankshaft rotates once, there has been a limit on the improvement in the rate of fluctuation of the rotational speed because the difference in these amounts of change in the rotational speed could not be precisely detected and reflected in the control.
Particularly, when the load of the engine is an AC generator that obtains AC voltage at a commercial frequency, an output frequency of the generator must be accurately maintained at a commercial frequency (50 or 60 Hz) and a high-quality AC output having little frequency fluctuation must be obtained; therefore, the control gain must be set with precision in accordance with the fluctuation in the rotational speed of the engine when the rotational speed fluctuates due to load fluctuation in the generator, and it must be possible to cause the rotational speed of the engine to quickly converge on the target rotational speed.
An object of the present invention is to provide an engine rotational speed variation amount detecting device in which the rotational speed variation amount occurring while the crankshaft rotates through a set angular range can be detected at least twice while the crankshaft rotates once, and the rotational speed variation amount can be detected with greater precision than in the prior art.
Another object of the present invention is to provide an engine control device in which control causing the rotational speed of the engine to converge on a target rotational speed can be performed with precision in response to load fluctuations using the aforementioned rotational speed variation amount detecting device.
The present invention is applied to a rotational speed variation amount detecting device that detects a rotational speed variation amount of a multi-cylinder four-cycle engine provided with an engine body having a plurality of cylinders and a crankshaft linked to pistons provided respectively within the plurality of cylinders, and a plurality of ignition units provided correspondingly with respect to each of the plurality of cylinders, the ignition units each being provided with a generating coil that generates AC voltage once per one rotation of the crankshaft, the AC voltage having a waveform in which a first half-wave, a second half-wave of different polarity from the first half-wave, and a third half-wave of the same polarity as the first half-wave appear in the stated order.
The rotational speed variation amount detecting device according to the present invention is provided with: a rotation signal generation means that detects a specific portion of the waveform of the AC voltage outputted by the generating coil provided to the ignition unit corresponding to each of the cylinders, and generates a rotation signal that corresponds to each of the cylinders once per one rotation of the crankshaft; a rotation signal generation interval detection means that, every time the rotation signal generation means generates the rotation signal that corresponds to each of the cylinders, detects, as a rotation signal generation interval for each of the cylinders, an amount of time elapsed from the previous generation to the current generation of the rotation signal that corresponds to each of the cylinders; and a rotation signal generation interval change amount calculation means that, every time the rotation signal generation interval detection means newly detects the rotation signal generation interval for the cylinders, calculates, as a rotation signal generation interval change amount, either a difference between a newly detected rotation signal generation interval for each of the cylinders and a previously detected rotation signal generation interval for the same cylinder or a difference between the newly detected rotation signal generation interval for each of the cylinders and the most recently detected rotation signal generation interval for the other cylinder. And the rotational speed variation amount detecting device is configured so as to detect the rotational speed variation amount of the engine on the basis of the rotation signal generation interval change amount calculated by the rotation signal generation interval change amount calculation means every time the rotation signal generation interval detection means detects the rotation signal generation interval for each of the cylinders.
As described above, when the rotational speed variation amount detecting device is configured so as to detect the rotational speed variation amount of the engine on the basis of the amount of change in the rotation signal generation intervals calculated by the rotation signal generation interval change amount calculation means every time the rotation signal generation interval detection means detects rotation signal generation intervals (amounts of time elapsed from the previous generation to the current generation of rotation signals) for each of the cylinders, the rotational speed variation amount of the engine can be detected a plurality of times during one rotation of the crankshaft, and the rotational speed variation amount of the engine can therefore be detected with greater precision than in the prior art.
The present invention is also applied to an engine control device that performs control causing a rotational speed of a multi-cylinder four-cycle engine to converge on a target rotational speed, the engine being provided with an engine body having a plurality of cylinders and a crankshaft linked to pistons provided respectively within the plurality of cylinders, and a plurality of ignition units provided correspondingly with respect to each of the plurality of cylinders, the ignition units each being provided with a generating coil that generates AC voltage once per one rotation of the crankshaft, the AC voltage having a waveform in which a first half-wave, a second half-wave of different polarity from the first half-wave, and a third half-wave of the same polarity as the first half-wave appear in the stated order.
In the present invention, the engine control device is provided with an operating part operated in order to adjust the rotational speed of the engine, a speed deviation calculation part that calculates a deviation between an actual rotational speed of the engine and the target rotational speed, a rotational speed variation amount detecting device that detects an rotational speed variation amount of the engine that has occurred while the crankshaft rotated through a set angular range, a control gain setting part that sets a control gain in accordance with the rotational speed variation amount detected by the rotational speed variation amount detecting device, an operation amount calculation part that calculates an operation amount of the operating part needed in order to cause the rotational speed of the engine to converge on the target rotational speed using the deviation calculated by the speed deviation calculation part and the control gain set by the control gain setting part, and an operating part drive means that drives the operating part so as to operate the operating part by the operation amount calculated by the operation amount calculation part.
In the present invention, the rotational speed variation amount detecting device is provided with: a rotation signal generation means that detects a specific portion of the waveform of the AC voltage outputted by the generating coil provided to the ignition unit corresponding to each of the cylinders of the engine, and generates a rotation signal that corresponds to each of the cylinders of the engine once per one rotation of the crankshaft; a rotation signal generation interval detection means that, every time the rotation signal generation means generates the rotation signal that corresponds to each of the cylinders, detects, as a rotation signal generation interval for each of the cylinders, an amounts of time elapsed from the previous generation to the current generation of rotation signal that corresponds to each of the cylinders; and a rotation signal generation interval change amount calculation means that, every time the rotation signal generation interval detection means newly detects the rotation signal generation interval for each of the cylinders, calculates, as a rotation signal generation interval change amount, either a difference between a newly detected rotation signal generation interval for each of the cylinders and a previously detected rotation signal generation interval for the same cylinder or a difference between a newly detected rotation signal generation interval for each of the cylinders and the most recently detected rotation signal generation interval for the other cylinder. And the rotational speed variation amount detecting device is configured so as to detect the rotational speed variation amount of the engine on the basis of the rotation signal generation interval change amount calculated by the rotation signal generation interval change amount calculation means every time the rotation signal generation interval detection means detects the rotation signal generation interval for each of the cylinders.
When the engine control device is configured as described above, the rotational speed variation amount that has occurred while the crankshaft of the engine has rotated through a set angular range can be detected a plurality of times while the crankshaft rotates once, and the control gain can be corrected to an appropriate value every time an rotational speed variation amount is detected; therefore, control causing the rotational speed of the engine to converge on the target rotational speed can be performed with precision, the rotational speed of the engine can be caused to quickly converge on the set speed during a load fluctuation, the rate of fluctuation in the rotational speed of the engine can be improved, and the load can be actuated with stability.
Further aspects of the present invention are made clear by the description of the embodiments of the invention, given hereinafter.
The device for detecting a rotational speed variation amount in an engine according to the present invention is provided with: a rotation signal generation means that detects a specific portion of the waveform of the AC voltage outputted by the generating coil provided to each of the ignition units corresponding to each of the cylinders of the engine, and generates a rotation signal that corresponds to the cylinders once per one rotation of the crankshaft; a rotation signal generation interval detection means that detects, as a rotation signal generation interval for each of the cylinders, an amount of time elapsed from the previous generation to the current generation of rotation signal that corresponds to each of the cylinders, every time the rotation signal is generated; and a rotation signal generation interval change amount calculation means that calculates, as a rotation signal generation interval change amount, either a difference between a newly detected rotation signal generation interval for each of the cylinders and a previously detected rotation signal generation interval for the same cylinder or a difference between a newly detected rotation signal generation interval for each of the cylinders and most recently detected rotation signal generation interval for the other cylinder, every time the rotation signal generation interval detection means newly detects a rotation signal generation interval for each of the cylinders; and the rotational speed variation amount detecting device is configured so as to detect the rotational speed variation amount of the engine on the basis of the rotation signal generation interval change amount calculated by the rotation signal generation interval change amount calculation means every time the rotation signal generation interval detection means detects rotation signal generation intervals for the cylinders; therefore, the rotational speed variation amount of the engine can be detected a plurality of times while the crankshaft rotates once, and the rotational speed variation amount of the engine can be detected with greater precision than in the prior art.
With the device for detecting a rotational speed variation amount in an engine according to the present invention, an encoder, a pickup coil, or another special signal generator is not used, a specific portion is detected in the waveform of the AC voltage outputted by the generating coil provided to the ignition unit which is an essential component for actuating the engine, and the generated rotation signal is used to obtain information on the rotational speed of the engine; therefore, the rotational speed variation amount of the engine can be detected without complicating the structure of the engine.
With the engine control device according to the present invention, the rotational speed variation amount that has occurred while the engine made a rotation through the set angular range is detected a plurality of times during one rotation of the engine, and the control gain can be corrected to an appropriate value every time the rotational speed variation amount is detected; therefore, control causing the rotational speed of the engine to converge on the target rotational speed can be performed with higher accuracy than in the prior art, the rate of fluctuation of the rotational speed of the engine can be improved, and the actuation of the load can be stabilized.
In a V-type, two-cylinder, four-cycle engine, it is often the case that different values are observed in the rotational speed variation amount occurring when the crankshaft rotates through a range from the ignition position of the first cylinder to the ignition position of the second cylinder, and the rotational speed variation amount occurring when the crankshaft rotates through a range from the ignition position of the second cylinder to the ignition position of the first cylinder, but in the engine control device according to the present invention, these amounts of change in the rotational speed can be detected individually; therefore, the resolution of the detection of the rotational speed variation amount is increased, control causing the rotational speed to converge on the target rotational speed can be performed with precision, and control causing the rotational speed of the engine to converge on the target rotational speed can be performed with higher accuracy than in the prior art.
Embodiments of the present invention are described in detail below with reference to the drawings.
The present invention can be applied to a multi-cylinder four-cycle engine having n (n is an integer of 2 or greater) cylinders. In the embodiments presented below, the engine is a V-type two-cylinder four-cycle engine.
In a four-cycle engine, spark discharge is caused by a spark plug attached to a cylinder of the engine at a regular ignition position set near a crank angle position (rotational position of a crankshaft of the engine) at which a piston in the cylinder reaches top dead center in a compression stroke, and fuel is caused to combust inside the cylinder once with every two rotations of the crankshaft. Therefore, an ignition device is preferably caused to perform an ignition action once with every two rotations of the crankshaft in order to cause the engine to rotate. To cause the ignition action to be performed once with every two rotations of the crankshaft, a stroke determination must be performed to determine whether the stroke ending when the piston reaches top dead center is a compression stroke or an exhaust stroke. Therefore, a camshaft sensor or another special sensor that generates a signal once with every two rotations of the crankshaft must be attached to the engine. However, a structure of the engine becomes complicated when the special sensor is attached to the engine. Therefore, ignition devices are often configured such that the ignition action is allowed to be performed even in a final stage of the exhaust stroke, and the ignition action is performed near a crank angle position at which the piston reaches top dead center with every rotation of the crankshaft. In the embodiments presented below, the present invention is applied to a one-firing-per one rotation, multi-cylinder, four-cycle engine in which the ignition action is performed with every rotation of the crankshaft.
The term “ignition action” in the present specification means an action in which a high voltage is applied from a secondary coil of an ignition coil provided to the ignition device to spark plug attached to the cylinder of the engine, and spark discharge is caused in the spark plug of the cylinder. This term incorporates both an irregular ignition action performed at a crank angle position near the final stage of the exhaust stroke, and a regular ignition action performed at a crank angle position near the final stage of the compression stroke. The spark caused by the irregular ignition action performed at a crank angle position near the final stage of the exhaust stroke is considered to be a wasteful ignition.
In the present specification, the term “ignition period” or “ignition position” is used where appropriate, with “ignition period” meaning a timing (point in time) at which ignition is performed, and “ignition position” meaning a crank angle position (rotational position of the crankshaft) at which ignition is performed. In the description of the configuration and actions of the present invention, the term “ignition period” is used when the time at which the ignition action is performed is an issue and the term “ignition period” is used when the crank angle position at which the ignition action is performed is an issue.
Provided at head parts of the first cylinder 101 and the second cylinder 102 are intake ports opened and closed by intake valves, and exhaust ports opened and closed by exhaust valves. The intake ports of the first cylinder 101 and the second cylinder 102 are connected to a throttle body 106 via intake manifolds 104 and 105, respectively, and the exhaust ports of the first cylinder 101 and the second cylinder 102 are connected to an exhaust pipe (not shown) via exhaust manifolds 107 and 108, respectively. In the illustrated example, an injector (fuel injection valve) INJ is attached to the throttle body 106, and fuel is injected from the injector INJ into a space inside the throttle body 106. A throttle valve THV constituting an operating part, which is operated when a rotational speed of the engine is adjusted is attached to the throttle body 106 upstream of the injector INJ. The throttle valve THV is operated by an actuator 5 composed of a stepping motor, etc.
A first spark plug PL1 and a second spark plug PL2 are respectively attached to the head part of the first cylinder 101 and the head part of the second cylinder 102, and discharge gaps in these spark plugs are inserted into combustion chambers inside the first cylinder 101 and the second cylinder 102.
The V-type two-cylinder four-cycle engine shown in
A flywheel 109 is attached to one end of the crankshaft 103, and a permanent magnet is attached to an outer periphery of the flywheel 109, whereby a magnetic rotor M is configured having a three-pole magnetic pole part in which S poles are formed on both sides of an N pole. The first ignition unit IU1 and the second ignition unit IU2, provided respectively for the first cylinder 101 and the second cylinder 102 of the engine, are disposed on an outer side of the flywheel 109. The first ignition unit IU1 and the second ignition unit IU2 constitute main parts of ignition devices that ignite the first cylinder 101 and the second cylinder 102, respectively. These ignition units are disposed at positions suitable for causing the ignition action to be performed in the corresponding cylinder and secured to ignition unit attachment parts provided to a case, a cover, etc., of the engine. In the illustrated example, the first ignition unit IU1 is disposed at a position apart from the position of the second ignition unit IU2 by an angular interval of 90° forward in the direction of forward crankshaft rotation. A flywheel magnet is configured by the magnetic rotor M and the ignition units IU1 and IU2.
The ignition units IU1, IU2 are each formed into a unit by having a case accommodate the following: an armature core having at both ends a magnetic pole part facing the magnetic poles of the magnetic rotor M with gaps interposed therebetween; an ignition coil provided with a primary coil and a secondary coil wound as generating coils around the armature core; a constituent element of a primary current control circuit that controls a primary current of the ignition coil so as to induce a high voltage for ignition in the secondary coil of the ignition coil during the ignition period of the engine; and a microprocessor or other constituent element constituting a control means that controls the primary current control circuit.
The primary current control circuit is a circuit that causes a rapid change in the primary current of the ignition coil at the ignition timing of the engine, and induces a high voltage for ignition in the secondary coil of the ignition coil. A capacitor discharge circuit and a current-blocking circuit are known as examples of primary current control circuits. In the present embodiment, a current-blocking circuit is used as the primary current control circuit.
Referring to
The primary current control switch SW is configured from a transistor, a MOSFET, or another semiconductor switch element, and is put into an ON state by the sending of a drive signal from the primary coil W1 side when a voltage of a predetermined polarity has been induced in the primary coil W1 of the ignition coil.
The voltage detection circuit DV is configured from a resistance-voltage-dividing circuit, etc., connected in parallel to both ends of the primary coil W1 of the ignition coil. The voltage detection circuit DV detects voltages (primary voltages) across the primary coils of the ignition coils of the ignition units IU1 and IU2 and outputs primary voltage detection signals V11 and V12 during the ignition period
of the first cylinder and the second cylinder. The primary voltage detection signal V11 outputted from the voltage detection circuit DV of the first ignition unit IU1 and the primary voltage detection signal V12 outputted from the voltage detection circuit DV of the second ignition unit IU2 are sent to the electronic control unit 2 shown in
When three magnetic poles are provided to the magnetic rotor M, an AC voltage Ve is generated once per one rotation of the crankshaft in the primary coils W1 of the ignition coils IG provided to the ignition units IU1, IU2, this AC voltage Ve having a waveform in which a first half-wave voltage Ve1, a second half-wave voltage Ve2 of reverse polarity (positive polarity in the illustrated example) to the first half-wave voltage Ve1, and a third half-wave voltage Ve3 of the same polarity (negative polarity in the illustrated example) as the first half-wave voltage Ve1 appear in the stated order as shown in
The ignition control part Cont shown in
Commonly, in an ignition device for an engine, the rotational speed of the engine is detected, the ignition position θi of the engine is calculated relative to the detected rotational speed, and a high voltage for ignition is applied to the spark plug when the calculated ignition position has been detected, causing an ignition action to be performed.
To enable the ignition position θi to be detected, a reference position is set to a crank angle position advanced further past a maximum advance position of the ignition position of the engine, the reference signal Sf is caused to be generated at this reference position, and when this reference signal is generated, an ignition timer is set to the amount of time needed for the crankshaft to rotate from the reference position to the ignition position as a measurement time for ignition position detection, and measurement of this amount of time is initiated. When the measurement of the measurement time set to the ignition timer is completed, the primary current control switch SW is set to an OFF state and the ignition action is performed. In the present embodiment, a position θ1 where the first half-wave voltage Ve1 is generated, of the parts of the waveform of the voltage Ve induced in the primary coil of the ignition coil, is set as a reference position and the reference signal Sf is generated at this reference position θ1.
The reference signal generation means 11 shown in
The signal identification means that identifies the reference signal Sf can be configured, for example, so as to measure the intervals at which the falls f, f′, . . . in the rectangular-wave voltage Vq occur, and to identify, as the reference signal Sf, the fall f occurring at the start of the time period of the first half-wave voltage Ve1, making use of the fact that the relationship Ta<<Tb exists between a time Ta that elapsed from the fall f until the fall f′ occurring immediately thereafter, and a time Tb that elapsed from the fall f′ until the next fall f.
The rotational speed detection means 12 shown in
The ignition position calculation means 13 is a means that calculates the ignition position θi at the rotational speed detected by the rotational speed detection means 12. The ignition position calculation means 13 calculates measurement values (measurement times for ignition position detection) measured by the ignition timer in order to detect the ignition position at each rotational speed of the engine, by, for example, conducting an interpolative calculation on a value obtained by searching an ignition position calculation map for the rotational speed detected by the rotational speed detection means 12.
The software-based processes needed to constitute the reference signal generation means 11, the rotational speed detection means 12, the ignition position calculation means 13, and the ignition position detection means 14 are performed by microprocessors provided inside the ignition units IU1, IU2.
The primary current control switches SW provided to the ignition units IU1, IU2 are put into an ON state due to a drive signal being sent by the second half-wave voltage Ve2 when this voltage Ve2 is induced in the primary coil of the ignition coil in each unit, and a short-circuit current is flowed to the primary coil of the ignition coil.
When the reference signal generation means 11 in each of the ignition units IU1, IU2 has generated the reference signal Sf, the ignition position detection means 14 provided to each of the ignition units sets the ignition timer to an amount of time to be measured by the ignition timer in order to detect the ignition position, initiates measurement of the set amount of time, and sends an ignition command to the switch control means 15 of each of the ignition units when the ignition timer completed measurement of the set amount of time.
The switch control means 15 of each of the ignition units is a means that puts the primary current control switch SW of the respective ignition unit into an OFF state when an ignition command has been sent from the ignition position detection means 14. This means is configured from, for example, a means that bypasses the drive signal sent to the primary current control switch SW inside the respective ignition unit, the means bypassing the signal from the primary current control switch.
In each of the ignition units, when the switch control means 15 bypasses from the primary current control switch SW the drive signal sent to the switch SW, the primary current control switch SW is put into an OFF state, and the primary current of the ignition coil is blocked. At this time, a high voltage oriented toward causing the primary current that had been heretofore flowing to continue to flow is induced in the primary coil of the ignition coil. This voltage is boosted by a boosting ratio between the primary and secondary coils of the ignition coil, and a high voltage for ignition is therefore induced in the secondary coil of the ignition coil of each of the ignition units. The high voltages for ignition induced in the secondary coils of the ignition coils provided respectively to the ignition units IU1 and IU2 are applied respectively to the spark plugs PL1 and PL2, spark discharge therefore occurs in the spark plugs, and the engine is ignited.
When the primary current control switch SW is put into the OFF state to induce the high voltage for ignition in the secondary coil of the ignition coil, a pulse-form spike voltage (ignition pulse) Spy is induced in the primary coil of the ignition coil as shown in
The electronic control unit (ECU) 2 shown in
The primary voltage detection signals V12 and V12 respectively outputted from the primary voltage detection circuit DV (see
The waveform-shaping circuits 201, 202 can be configured from, for example, a circuit designed to obtain a rectangular-wave signal at a collector of the transistor provided so as to go into an ON state upon being sent a base current while the voltage at both ends of the primary coil of the corresponding ignition coil is equal to or greater than a threshold value, or a monostable multivibrator that is triggered by an ignition pulse equal to or greater than a threshold value to generate a rectangular-wave pulse having a constant pulse width.
In the present embodiment, a rotor of an AC generator (not shown in
In an engine generator that generates an AC voltage at a commercial frequency, an output frequency of the engine must be kept constant; therefore, when a load of the generator fluctuates and a rotational speed of the engine fluctuates, control must be quickly performed to cause the rotational speed of the engine to converge on a target rotational speed. To quickly perform control on the rotational speed of the engine, a control gain multiplied by a deviation between the actual rotation speed of the engine and the target rotational speed must be set not to a fixed value, but to a value that is appropriate according to an rotational speed variation amount of the engine (a degree of the change in the rotational speed of the engine) that occurs while the crankshaft is rotating through a set angular range.
In the present embodiment, control of the ignition period of the engine is performed by the ignition control parts Cont built into the first ignition unit IU1 and the second ignition unit IU2. The electronic control unit 2 is used to perform control of the injector (fuel injection valve) that supplies fuel to the engine, and control that causes the rotational speed of the engine to converge on the target rotational speed when the rotational speed of the engine has fluctuated due to load fluctuation in the generator.
Referring to
The IU1 and IU2 are respectively a first ignition unit and a second ignition unit provided for the first cylinder 101 and the second cylinder 102, and an AC voltage Ve having a waveform in which a first half-wave Ve1, a second half-wave Ve2 of different polarity from the first half-wave, and a third half-wave Ve3 of the same polarity as the first half-wave appear in the stated order, as shown in
In
In the present embodiment, the first rotation signal generation means 203 that detects a specific portion of the waveform of the primary voltage of the first ignition coil IG1 and generates the rotation signal S1 for the first cylinder is configured from the first waveform-shaping circuit 201 shown in
In the example shown in
More specifically, the rotation signal generation interval detection means 2A is a means that detects as a signal generation interval for the cylinders, an amount of time elapsed from the previous generation of a rotation signal that corresponds to each of the cylinders to the current generation of a rotation signal that corresponds to each of the cylinders, every time the rotation signal generation means 203, 204 generate rotation signals that correspond to the cylinders. The rotation signal generation interval(time interval) for the first cylinder 101 and the rotation signal generation interval for the second cylinder 102 are amounts of time needed for the crankshaft to rotate once, and information on the rotational speed of the crankshaft can therefore be obtained from both of these rotation signal generation intervals.
The rotation signal generation interval change amount calculation means 2B is a means that calculates, as a rotation signal generation interval change amount every time the rotation signal generation interval detection means newly detects the rotation signal generation interval for each of the cylinders, either a difference between the newly detected rotation signal generation interval for each of the cylinders and the previously detected rotation signal generation interval for the same cylinder, or a difference between a newly detected rotation signal generation interval for each of the cylinders and the previously detected rotation signal generation interval for the other cylinder. The rotational speed variation amount detection means 2C is a means that detects the rotational speed variation amount of the engine, which occurred while the crankshaft rotated through a set angular range, the set angular range being 360 degrees in the present embodiment, on the basis of a rotation signal generation interval change amount calculated by the rotation signal generation interval change amount calculation means 2B every time the rotation signal generation interval detection means 2A detects the rotation signal generation interval for each of the cylinders.
In
The control gain calculation part 2G can be configured so as to calculate the control gain by searching a control gain calculation map for parameters including information on the rotational speed variation amount. As is well known, control gains used in feedback control are proportional gain, integral gain, and differential gain. Of these control gain, proportional gain must always be calculated, and integral gain and differential gain are calculated only when there are an integral term and a differential term in a calculation formula for finding an operation amount.
In the engine control device according to the present invention, a control gain is calculated for at least the parameter including information on the rotational speed variation amount of the engine, but there is nothing hindering the use of the other parameter such as a target rotational speed in addition to the parameter including information on the rotational speed variation amount as the parameter used when the control gain is calculated.
In
In the present embodiment, the operating part 2J is configured from the throttle valve THV, and the operating part drive means 21 is configured from the drive circuit 207 shown in
When the present invention is carried out, the data indicating the rotational speed of the engine may be the rotation signal generation intervals (time intervals) alone, or the data may be the rotational speed of the engine found from the rotation signal generation intervals and the rotational angle from the previous ignition position to the current ignition position.
In the V-type two-cylinder four-cycle engine shown in
The first rotation signal generation means 203 shown in
Every time the first rotation signal generation means 203 and the second rotation signal generation means 204 respectively generate the first rotation signal S1 corresponding to the first cylinder and the second rotation signal S2 corresponding to the second cylinder, the rotation signal generation interval detection means 2A shown in
In
In
In
Similarly, #2N1 includes information on the average rotational speed of the crankshaft while the crankshaft rotates through a 360° range from the fourth crank angle position θi4 to the second crank angle position θi2, and #2N0 includes information on the average rotational speed of the crankshaft while the crankshaft rotates through a 360° range from the second crank angle position θi2 to the fourth crank angle position θi4. Therefore, when an absolute value |#2N0−#2N1| of a difference between the newly detected rotation signal generation interval #2N0 and the previously detected rotation signal generation interval #2N1 is found as the amount of change in the rotation signal generation interval, information on the rotational speed variation amount that has occurred while the crankshaft rotated through the 360° range can be obtained from the value of this amount of change in the rotation signal generation interval.
Every time the rotation signal generation interval detection means 2A detects rotation signal generation intervals for each of the cylinders, the rotational speed variation amount detection means 2C shown in
When the first cylinder and the second cylinder are disposed at an angular interval less than 180° (an angular interval of 90° in the present embodiment) as in the engine used in the present embodiment, the angle (270° in the present embodiment) of the range from the ignition position of the first cylinder to the ignition position of the second cylinder and the angle (90° in the present embodiment) from the ignition position of the second cylinder to the ignition position of the first cylinder are different. Therefore, a difference arises between the rotational speed variation amount occurring while the crankshaft rotates through the range from the ignition position of the first cylinder to the ignition position of the second cylinder, and the rotational speed variation amount occurring while the crankshaft rotates through the range from the ignition position of the second cylinder to the ignition position of the first cylinder. However, in the present embodiment, the rotational speed variation amount can be detected twice while the crankshaft rotates once; therefore, the rotational speed variation amount of the engine can be precisely detected and the control gain can be appropriately set.
In the above description, the difference between the newly detected rotation signal generation intervals for each of the cylinders and the previously detected rotation signal generation intervals for each of the cylinders is found as the amount of change in the rotation signal generation intervals, and the rotational speed variation amount occurring while the crankshaft rotates through a set angular (360° in the present embodiment) range is detected from this amount of change in the rotation signal generation intervals, but another possible option is that the difference between the rotation signal generation interval for each cylinder newly detected by the rotation signal generation interval detection means and the most recent previously detected rotation signal generation interval for the other cylinder be calculated as the amount of change in the rotation signal generation intervals, and the rotational speed variation amount occurring while the crankshaft rotates through a set angular range be detected from this amount of change in the rotation signal generation intervals.
For example, in
Similarly, when the rotation signal generation interval #2N0 for the second cylinder has been detected and an absolute value |#2N0−#1N0| of a difference with the most recent previously detected rotation signal generation interval #1N1 for the first cylinder is found as the amount of change in the rotation signal generation interval, information can be obtained on the rotational speed variation amount that has occurred while the crankshaft rotated through a 270° (=α°) range from the third crank angle position θi3 to the fourth crank angle position θi4, and information on the rotational speed variation amount that has occurred while the crankshaft rotated 360° can be obtained by performing the calculation |#2N0−#1N1|×(360/270) and converting the amount of change in the rotation signal generation interval that has occurred while the crankshaft rotated through the 270° range to the amount of change in the rotation signal generation interval that has occurred while the crankshaft rotated 360°.
Thus, when the difference between the rotation signal generation interval for each cylinder newly detected by the rotation signal generation interval detection means and the most recent previously detected rotation signal generation interval for the other cylinder is calculated as the amount of change in the rotation signal generation interval, and the rotational speed variation amount that has occurred while the crankshaft rotated through a set angular (360° in the above example) range is detected from this amount of change in the rotation signal generation interval, the responsiveness of detecting the rotational speed variation amount can be improved.
The aforementioned set angle is not limited to 360°; the set angle may be set to 180°, 270°, or another angle.
The rotation signal generation interval detection means 2A shown in
The rotation signal generation interval detection means 2A shown in
The first timing means 2A1 shown in
The first rotation signal generation interval change amount calculation means 2B1 shown in
The second rotation signal generation interval change amount calculation means 2B2 can be configured so as to calculate, as the second first rotation signal generation interval change amount, the absolute value |#2N0−#2N1| of the difference between the second rotation signal generation interval #2N0 newly measured by the second timing means 2A2 and the second rotation signal generation interval #2N1 previously measured by the second timing means 2A2. In this case as well, the rotational speed variation amount detection means 2C is configured so as to detect the rotational speed variation amount of the engine every time the first rotation signal generation interval change amount calculation means 2B1 and the second rotation signal generation interval change amount calculation means 2B2 respectively calculate the first rotation signal generation interval change amount and the second rotation signal generation interval change amount.
Referring to
The rotation signal generation interval detection means 2A shown in
The rotation signal generation interval change amount calculation means 2B is configured from a first per-range rotation signal generation interval change amount calculation means 2B1a, a second per-range rotation signal generation interval change amount calculation means 2B2a, a first rotation signal generation interval change amount calculation means 2B b, and a second rotation signal generation interval change amount calculation means 2B2b.
The first per-range rotation signal generation interval change amount calculation means 2B1a is a means that calculates, as a first per-range rotation signal generation interval change amount including information on the rotational speed variation amount of the crankshaft that has occurred while the crankshaft rotated through a (360−α°) range, an absolute value of a difference between the currently measured first rotation signal generation interval and the second rotation signal generation interval measured by the second timing means 2A2 immediately before the first timing means 2A1 measured this first rotation signal generation interval, this calculation being made every time the first timing means 2A1 measures the first rotation signal generation interval.
The second per-range rotation signal generation interval change amount calculation means 2B2a is a means that calculates, as a second per-range rotation signal generation interval change amount including information on the rotational speed variation amount of the crankshaft that has occurred while the crankshaft rotated through an α° range, an absolute value of a difference between the currently measured second rotation signal generation interval and the first rotation signal generation interval measured by the first timing means 2A1 immediately before the second timing means 2A2 measured this second rotation signal generation interval, this calculation being made every time the second timing means 2A2 measures the second rotation signal generation interval.
Furthermore, the first rotation signal generation interval change amount calculation means 2B1b is a means that performs a calculation to convert the first per-range rotation signal generation interval change amount to a first rotation signal generation interval change amount including information on the amount of change in speed during one crankshaft rotation, and the second rotation signal generation interval change amount calculation means 2B2b is a means that performs a calculation to convert the second per-range rotation signal generation interval change amount to a second rotation signal generation interval change amount including information on the amount of change in speed during one crankshaft rotation.
The rotational speed variation amount detection means 2C is a means that detects the rotational speed variation amount of the engine every time the first rotation signal generation interval change amount calculation means 2B1b and the second rotation signal generation interval change amount calculation means 2B2b respectively calculate the first rotation signal generation interval change amount and the second rotation signal generation interval change amount.
In a case in which the engine is configured so that a spark discharge caused in the first spark plug PL1 and the second spark plug PL2 due to a high voltage for ignition being applied from the first and second ignition coils IG1 and IG2 respectively to the first and second spark plugs PL1 and PL2 attached respectively to the first cylinder 101 and the second cylinder 102 of the engine, the first and second timing means, the first and second per-range rotation signal generation interval change amount calculation means, and the first and second rotation signal generation interval change amount calculation means can be configured as described below.
Specifically, the first timing means 2A1 can be configured so as to measure the rotation signal generation interval of the first cylinder 101 by measuring the generation interval of the first rotation signal S1 generated by the first rotation signal generation means 203 when a high voltage for ignition is applied from the first ignition coil IG1 to the first spark plug PL1. Additionally, the second timing means 2A2 can be configured so as to measure the rotation signal generation interval of the second cylinder 102 by measuring the generation interval of the second rotation signal S2 generated by the second rotation signal generation means 204 when a high voltage for ignition is applied from the second ignition coil IG2 to the second spark plug PL2.
The first per-range rotation signal generation interval change amount calculation means 2B1a can be configured so as to calculate, as the first per-range rotation signal generation interval change amount, the absolute value |#1N0−#2N0| of the difference between the newly measured first rotation signal generation interval #1N0 and the second rotation signal generation interval #2N0 measured by the second timing means 2A2 immediately before the first timing means 2A1 measured the first rotation signal generation interval #1N0, this calculation being made every time the first timing means 2A1 measures the first rotation signal generation interval #1N0. Additionally, the second per-range rotation signal generation interval change amount calculation means 2B2a can be configured so as to calculate, as the second per-range rotation signal generation interval change amount, the absolute value |#2N0−#1N1| of the difference between the newly measured second rotation signal generation interval #2N0 and the first rotation signal generation interval #1N1 measured by the first timing means immediately before the second timing means 2A2 measures the second rotation signal generation interval #2N0, this calculation being made every time the second timing means 2A2 measures the second rotation signal generation interval #2N0.
The first rotation signal generation interval change amount calculation means 2B1b can be configured so as to perform the calculation |#1N0−#2N0|×{360/(360−α)} on the first per-range rotation signal generation interval change amount |#1N0−#2N0|, and to convert the first per-range rotation signal generation interval change amount to a first rotation signal generation interval change amount including information on the amount of change in rotational speed during one rotation of the crankshaft. The second rotation signal generation interval change amount calculation means 2B2b can be configured so as to perform the calculation |#2N0−#1N1|×(360/a) on the second per-range rotation signal generation interval change amount |#2N0−#1N|, and to convert the second per-range rotation signal generation interval change amount to a second rotation signal generation interval change amount including information on the amount of change in rotational speed during one rotation of the crankshaft.
In the embodiment described above, a flywheel magnet is attached to the engine, the flywheel magnet being provided with: a magnetic rotor M joined to the crankshaft of the engine; and ignition units IU1 and IU2, each formed into unit by having a case accommodate an armature core having at both ends a magnetic pole part facing magnetic poles of the magnetic rotor with gaps interposed therebetween, an ignition coil composed of a primary coil and a secondary coil wound around the armature core, and a constituent element of a primary current control circuit that controls a primary current of the ignition coil so as to induce a high voltage for ignition in the secondary coil of the ignition coil at the ignition period of the engine, whereby a high voltage for ignition is applied to spark plugs IL1 and IL2 from the secondary coils of the ignition coils in the first ignition units IU1 and IU2. But the present invention can also be applied to a case of a configuration in which ignition units such as those described above are not used, ignition circuits that control the primary currents of the ignition coils IG1 and IG2 are provided within an electronic control unit (ECU) 2, and the ignition coils IG1 and IG2 are provided on the outside of the electronic control unit.
Next is a description, made with reference to
When the algorithm shown in
When the process using the algorithm shown in
When the first rotation signal generation means 203 generates the rotation signal S1 for the first cylinder at the ignition position of the first cylinder, first, in step S101 of
When it has been determined in step S102 of
When it has been determined in step S105 of
When the second rotation signal generation means 204 generates the second rotation signal S2 at the ignition position of the second cylinder, the S2 interruption process shown in
When it has been determined in step S202 that a previous measurement value exists, in step S203, a value obtained by subtracting the previous timer measurement value from the current measurement value is stored in the RAM as the current second rotation signal generation interval (#2N0), and in step S204, the newest rotational speed of the engine is detected from the current second rotation signal generation interval. Next, in step S205, a determination is made as to whether or not the previous second rotation signal generation interval (#2N1) has been calculated, and as a result of this determination, when it has been determined that the previous second rotation signal generation interval (#2N1) has not been calculated, the interruption process advances to step S209, a process is performed to designate the current timer measurement value measured in step S206 as the previous measurement value, and this process is then ended.
In step S205 of
When the process using the algorithm shown in
When the first rotation signal S1 is generated at the ignition position of the first cylinder of the engine, in step S301 of
When it has been determined in step S302 that a previous timer measurement value exists, the process advances to step S303, and a value obtained by subtracting the previous timer measurement value from the current measurement value is stored in the RAM as the newest first rotation signal generation interval (#1N0). The process then advances to step S304, and after the newest rotational speed of the engine has been detected from the newest first rotation signal generation interval, a determination is made in step S305 as to whether or not the newest second rotation signal generation interval (#2N0) has been calculated. As a result, when it has been determined that the newest second rotation signal generation interval (#2N0) has not been calculated, the interruption process transitions to step S309, a process is performed to designate the current timer measurement value measured in step S301 as the previous measurement value, and this process is then ended.
When it has been determined in step S305 of
The interruption process of
When it has been determined in step S402 that a previous measurement value exists, the process advances to step S403, and a value obtained by subtracting the previous timer measurement value from the current measurement value is stored in the RAM as the newest second rotation signal generation interval (#2N0). The process then advances to step S404, and after the newest rotational speed of the engine has been detected from the newest second rotation signal generation interval (#2N0), a determination is made in step S405 as to whether or not the newest first rotation signal generation interval (#1N1) has been calculated. As a result, when it has been determined that the newest first rotation signal generation interval (#1N1) has not been calculated, the interruption process transitions to step S409, a process is performed to designate the current timer measurement value measured in step S401 as the previous measurement value, and this interruption process is then ended.
When it has been determined in step S405 of
When the process using the algorithm shown in
In the embodiment described above, the rotation signal generation means are configured so as to detect ignition pulses induced in the primary coils of the ignition coils in the ignition units provided for the cylinders and to generate rotation signals that correspond to the cylinders during the ignition periods of the cylinders of the engine, but the rotation signals used in order to detect the rotational speed variation amount of the engine are preferably signals generated once at certain crank angle positions every time the crankshaft rotates once, and are not limited to signals generated due to ignition pulses being detected.
For example, the rotation signals can be signals generated by the detection of specific portions of the AC voltage Ve shown in
The present invention makes it possible to detect, a plurality of times while a crankshaft rotates once, an rotational speed variation amount of an engine that has occurred while the crankshaft rotates through a set angular range. The present invention is widely applicable to cases in which a control gain is set with precision in accordance with a degree of the change in rotational speed, and control must be quickly performed to cause the rotational speed of the engine to converge on a target rotational speed.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2017/023424 | 6/26/2017 | WO | 00 |