JP4759548B2 - Engine electronic governor - Google Patents

Description

  The present invention relates to an electronic governor for an engine.

  Recently, electronic governors that use an actuator to control the engine speed to a target speed are often used. When the engine is a diesel engine, the actuator adjusts the fuel supply amount so that the engine rotation speed approaches the target rotation speed by operating a metering rack that adjusts the fuel supply amount. This actuator has a hysteresis characteristic with respect to the actuator drive current, as shown by the solid line in FIG. FIG. 4 is a diagram illustrating the hysteresis characteristics of the actuator, where the vertical axis indicates the position of the metering rack that moves in accordance with the driving of the actuator, and the horizontal axis indicates the actuator driving current that drives the actuator. Due to this hysteresis characteristic, the actuator may not drive in response to changes in the actuator drive current. For example, if the actuator is driven so that the position of the metering rack is moved from point A to point B, the actuator will not be driven even if the actuator drive current is increased from point C to point D. Need to be increased. The width of the actuator drive current from point C to point D where the actuator is not driven is called the hysteresis width, and the actuator is not driven when the change width of the actuator drive current is shorter than the hysteresis width. In order to prevent the influence of this hysteresis characteristic, in the conventional electronic governor, the actuator is minutely oscillated by superimposing a dither current on the actuator drive current to improve the response of the actuator (see Patent Document 1). In order to minutely vibrate the actuator, the dither current amplitude (hereinafter referred to as dither width) is initially set to at least about half the hysteresis width of the actuator.

JP 2001-20789 A

  Thus, the dither width is initially set corresponding to the hysteresis width of the actuator, but the hysteresis width of the actuator varies depending on the engine temperature and the like.

  The actuator has a plunger, and moves the metering rack in the axial direction by moving the plunger in the axial direction. The sliding resistance of the metering rack changes depending on the viscosity of the engine oil that changes depending on the engine temperature, and the hysteresis width of the actuator also changes depending on the engine temperature. That is, when the engine temperature is lowered and the viscosity of the engine oil is increased, the hysteresis width of the actuator is increased. When the engine temperature is increased and the viscosity of the engine oil is decreased, the hysteresis width of the actuator is decreased.

  FIG. 5 is a diagram showing that the hysteresis width of the actuator is increased by changing the engine temperature. As shown in FIG. 5, the hysteresis width after the engine temperature is lowered (for example, the width from the F point to the G point on the broken line) is the initial hysteresis width (for example, the width from the H point to the I point on the solid line). ) Bigger. For this reason, at the time of cold start, the hysteresis width increases due to a decrease in the engine temperature, and the dither width that is initially set corresponding to the initial hysteresis width becomes smaller than half of the hysteresis width of the actuator. As a result, the actuator and the metering rack do not vibrate slightly, and there is a risk that the response of the actuator will be reduced by the hysteresis characteristic. On the other hand, at the time of warm start, if the dither width is kept large even though the hysteresis width becomes small due to the increase in engine temperature, the dither becomes a disturbance of control and the control stability is lowered.

  The present invention provides an electronic governor for an engine that solves the above problems, that is, an electronic governor for an engine that can improve the response of an actuator during a cold start and maintain high control stability during a warm start. For the purpose.

(Invention of Claim 1)
As shown in FIG. 1, the actuator driving current for driving the actuator (2) is controlled to cause the actuator (2) to operate the fuel metering means. The fuel metering means causes the engine speed to approach the target speed. Adjust the fuel supply amount so that
A rotation speed detection means (3) for detecting the rotation speed of the engine, a target rotation speed setting means (4) for setting the target rotation speed, and the actuator drive current are controlled so that the rotation speed of the engine approaches the target rotation speed. Drive current control means (5), dither current superimposing means (6) for superimposing the dither current on the actuator drive current, and drive means (7) for outputting the actuator drive current with the dither current superimposed on the actuator (2) In the electronic governor of the equipped engine,
Disturbance determining means (8) for determining that the dither is a disturbance of control is provided, and the disturbance determining means (8) is linked to the dither current superimposing means (6),
As shown in FIG. 2A, when the engine is started, the dither current superimposing means (6) gradually increases the dither width of the dither current, and the disturbance discriminating means (8) causes the dither to become a control disturbance. In the engine governor, the dither width of the dither current increased by the dither current superimposing means (6) is reduced based on the determination.

(Invention of Claim 2)
As shown in FIG. 1, the actuator driving current for driving the actuator (2) is controlled to cause the actuator (2) to operate the fuel metering means. The fuel metering means causes the engine speed to approach the target speed. Adjust the fuel supply amount so that
A rotation speed detection means (3) for detecting the rotation speed of the engine, a target rotation speed setting means (4) for setting the target rotation speed, and the actuator drive current are controlled so that the rotation speed of the engine approaches the target rotation speed. Drive current control means (5), dither current superimposing means (6) for superimposing the dither current on the actuator drive current, and drive means (7) for outputting the actuator drive current with the dither current superimposed on the actuator (2) In the electronic governor of the equipped engine,
Disturbance determining means (8) for determining that the dither is a disturbance of control is provided, and the disturbance determining means (8) is linked to the dither current superimposing means (6),
As shown in FIG. 3A, when the engine is started, the dither current superimposing means (6) increases the dither width of the dither current to a predetermined value, and the disturbance determining means (8) is the disturbance of the control of the dither. If it is determined, the dither current superimposing means (6) reduces the dither width of the dither current increased to a predetermined value based on this determination.

(Invention of Claim 1)
<Effect> It is possible to maintain high response of the actuator at the time of cold start.
When starting the engine, the dither width can be increased until just before the dither becomes a disturbance of control, so the minute vibrations of the actuator and fuel metering means (such as the metering rack) that increase the sliding resistance during cold start are appropriate. The response of the actuator during cold start can be maintained high.
<Effect> The stability of control during warm start can be maintained at a high level. When it is determined that the dither is a disturbance of control during engine start, the dither width of the dither current is reduced. Excessive vibrations of the actuator and fuel metering means (such as a metering rack) that sometimes reduce sliding resistance are prevented, and the control stability during warm start can be maintained high.

(Invention of Claim 2)
<Effect> It is possible to maintain high response of the actuator at the time of cold start.
Since the dither width can be increased to a predetermined value when the engine starts, minute vibrations of the actuator and fuel metering means (such as a metering rack) that increase the sliding resistance during cold start are properly performed, and the cold High response of the actuator at the time of starting can be maintained.

<Effect> The stability of control during warm start can be maintained at a high level. When it is determined that the dither is a disturbance of control when the engine is started, the dither width of the increased dither current is reduced. Excessive vibrations of the actuator and the fuel metering means (such as a metering rack) whose sliding resistance decreases during the warm start can be prevented, and the control stability during the warm start can be maintained high.

(Invention of Claim 3)
<Effect> It is possible to efficiently suppress the engine rotation fluctuation based on the dither disturbance.
The disturbance determination means (8) calculates a time difference Δt and an engine speed difference ΔR between adjacent peaks of the engine speed fluctuation, the time difference Δt is less than a predetermined time difference t, and the engine speed difference ΔR is a predetermined engine speed difference R. When the above number of times continues for a predetermined number n or more, the disturbance determination means (8) determines that the dither is a control disturbance, so the engine rotation fluctuation is based on fluctuations in the internal load or the like. Therefore, it is possible to clearly discriminate whether it is based on the disturbance of the dither, and it is possible to efficiently suppress the engine rotation fluctuation based on the disturbance of the dither.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an example of an electronic governor 1 for a diesel engine according to the first embodiment of the present invention. FIG. 2 is a diagram for explaining an electronic governor according to the first embodiment of the present invention. FIG. 2A is a graph for explaining the engine rotation fluctuation and the dither width, and FIG. This engine is used as a generator.
The electronic governor 1 according to the first embodiment of the present invention controls the actuator drive current that drives the actuator 2. When the controlled actuator driving current is output to the actuator 2, the actuator 2 operates a fuel supply adjusting means (not shown) for adjusting the fuel supply amount, so that the engine speed approaches the target speed. Adjust the fuel supply amount. The actuator 2 is a solenoid, and the actuator drive current is an excitation current. The fuel supply adjusting means is, for example, a fuel metering rack provided in the fuel injection pump, and adjusts the fuel supply amount to the engine.
The electronic governor 1 according to the first embodiment includes a rotation speed detection unit 3, a target rotation number setting unit 4, a drive current control unit 5, a dither current superimposing unit 6, a drive unit 7, and a dither that controls disturbance. Disturbance determining means 8 for determining that

The rotational speed detection means 3 detects the rotational speed of the engine. The rotation speed detection means 3 detects the rotation speed based on, for example, the actuator drive current or the number of pulses detected per rotation speed.
The target rotational speed setting means 4 sets the target rotational speed. The target rotation speed setting means 4 is, for example, a speed control lever.

The drive current control means 5 controls the actuator drive current so that the engine speed approaches the target speed. The drive current control means 5 includes a rotation speed deviation calculation means 51, a target current value calculation means 52, a current detection means 53, a current deviation calculation means 54, and a PWM signal calculation means 55. These means of the drive current control means 5 are realized by a computer such as an ECU, for example.
The rotational speed deviation calculating means 51 calculates the rotational speed deviation between the engine rotational speed and the target rotational speed. The target current value calculation means 52 sets the actuator drive current value so that the calculated rotation speed deviation is within an allowable range. The current detection means 53 performs A / D conversion on the current detected from the actuator by a shunt resistor (not shown), and calculates the detected current value of the actuator from the value after the A / D conversion. The current deviation calculation means 54 calculates a current value deviation between the set actuator drive current value and the detected current value of the actuator. The PWM signal calculation means 55 calculates the duty ratio of the PWM signal that makes the calculated current value deviation within an allowable range based on PID control.

The disturbance determining means (8) is linked to the rotation speed detecting means (3) and the dither current superimposing means (6). The dither current superimposing means (6) is linked to the rotation speed detecting means (3). When starting the engine, the dither current superimposing means (6) increases the dither width of the dither current to a predetermined value, and the disturbance determination means (8) determines that the dither is a control disturbance. The dither width of the dither current increased by the dither current superimposing means (6) is reduced based on the above. The dither width is adjusted after the engine is started.
As shown in FIGS. 2A and 2B, the disturbance discriminating means (8) calculates a time difference Δt and an engine speed difference ΔR between adjacent peaks of the engine speed fluctuation, and the time difference Δt is a predetermined time difference t. If the number of times that the rotational speed difference ΔR is greater than or equal to the predetermined rotational speed difference R continues for a predetermined number n or more, the disturbance determination means (8) determines that the dither is a control disturbance. Based on this determination, the dither current superimposing means (6) reduces the dither width of the dither current. The time difference t is 100 ms (milliseconds), the rotational speed difference R is 10 rpm, and the number of times n is 10 times. In general, the time difference associated with the load fluctuation of the external load and the load fluctuation of the internal load (based on the fluctuation of the sliding resistance of the bearing due to the rise in engine oil temperature, etc.) is 600 to 1000 ms, and the rotation speed difference is about 100 rpm. It is possible to clearly discriminate between rotation fluctuations due to load fluctuations and rotation fluctuations caused by dither.
FIG. 2B shows the engine speeds R0 to R7, the time differences Δt0 to Δt7, the rotational speeds at the generation times to to t7 of continuous fluctuations in the engine speed when the dither is a control disturbance. Differences ΔR1 to R7 are shown.

  As shown in FIG. 1, the dither current superimposing means 6 changes the dither width of the dither current based on the determination by the disturbance determining means (8), and then superimposes the dither current on the actuator drive current. The dither current superimposing unit 6 includes a dither width setting unit 61 and a PWM signal output unit 62. These means of the dither current superimposing means 6 are realized by a computer such as an ECU, for example.

  As shown in FIG. 1, the dither width setting means 61 changes the dither width of the dither current based on the determination by the disturbance determination means (8). That is, the dither width setting means 61 reduces the dither width of the dither current by reducing the pulse width of the dither signal based on the fact that the disturbance determination means (8) has determined that the dither is a control disturbance. To do.

  The PWM signal output means 62 superimposes a dither signal having a pulse width controlled to increase the dither width of the dither current on the PWM signal calculated by the PWM signal calculation means 55. Next, the PWM signal output means 62 outputs a PWM signal on which the dither signal is superimposed to the driving means 7.

  Based on the PWM signal input from the PWM signal output means 62, the drive means 7 outputs an actuator drive current on which the dither current is superimposed to the actuator 2. For example, when the actuator 2 is a solenoid, the driving unit 7 includes an excitation circuit.

FIG. 3 is a diagram for explaining the electronic governor according to the second embodiment, and FIG. 3 (A) is a graph for explaining the dither width at the time of engine start and the engine rotation variation according to the second embodiment. ) Is an enlarged view of a portion indicated by an arrow B in FIG.
When starting the engine, the dither current superimposing means (6) increases the dither width of the dither current to a predetermined value, and the disturbance determination means (8) determines that the dither is a control disturbance. The dither width of the dither current increased by the dither current superimposing means (6) is reduced based on the above.
Other configurations and functions are the same as those of the first embodiment, and the same reference numerals are given to the same elements as those of the first embodiment in FIG.

  The electronic governor described above is only one embodiment of the present invention, and the present invention is not limited to the above-described embodiments, and may be appropriately changed within the technical scope based on the claims. Can be implemented.

It is the block diagram which showed an example of the electronic governor which concerns on 1st Embodiment of this invention. FIG. 2A is a diagram for explaining an electronic governor according to the first embodiment of the present invention, FIG. 2A is a graph for explaining engine rotation fluctuation and dither width, and FIG. 2B is a portion viewed from arrow B in FIG. FIG. FIGS. 3A and 3B are diagrams illustrating an electronic governor according to a second embodiment of the present invention, FIG. 3A is a graph illustrating engine rotation fluctuation and dither width, and FIG. 3B is a view of FIG. It is an enlarged view of a part. It is the figure which showed the hysteresis characteristic of the actuator. It is a figure which shows that the hysteresis width of an actuator increases at the time of cold.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electronic governor 2 ... Actuator 3 ... Speed detection means 4 ... Target speed setting means 5 ... Drive current control means 6 ... Dither current superposition means 7 ... Drive means 8 ... Disturbance discrimination means

Claims (3)

By controlling the actuator drive current that drives the actuator (2), the actuator (2) operates the fuel metering means, and the fuel metering means adjusts the fuel supply amount so that the engine speed approaches the target speed. Let
A rotation speed detection means (3) for detecting the rotation speed of the engine, a target rotation speed setting means (4) for setting the target rotation speed, and the actuator drive current are controlled so that the rotation speed of the engine approaches the target rotation speed. Drive current control means (5), dither current superimposing means (6) for superimposing the dither current on the actuator drive current, and drive means (7) for outputting the actuator drive current with the dither current superimposed on the actuator (2) In the electronic governor of the equipped engine,
Disturbance determining means (8) for determining that the dither is a disturbance of control is provided, and the disturbance determining means (8) is linked to the dither current superimposing means (6),
When starting the engine, the dither current superimposing means (6) gradually increases the dither width of the dither current, and the disturbance determining means (8) determines that the dither is a control disturbance. An electronic governor for an engine, characterized in that the dither width of the dither current increased by the dither current superimposing means (6) based on the above is reduced. By controlling the actuator drive current that drives the actuator (2), the actuator (2) operates the fuel metering means, and the fuel metering means adjusts the fuel supply amount so that the engine speed approaches the target speed. Let
A rotation speed detection means (3) for detecting the rotation speed of the engine, a target rotation speed setting means (4) for setting the target rotation speed, and the actuator drive current are controlled so that the rotation speed of the engine approaches the target rotation speed. Drive current control means (5), dither current superimposing means (6) for superimposing the dither current on the actuator drive current, and drive means (7) for outputting the actuator drive current with the dither current superimposed on the actuator (2) In the electronic governor of the equipped engine,
Disturbance determining means (8) for determining that the dither is a disturbance of control is provided, and the disturbance determining means (8) is linked to the dither current superimposing means (6),
When starting the engine, the dither current superimposing means (6) increases the dither width of the dither current to a predetermined value, and the disturbance determination means (8) determines that the dither is a control disturbance. An electronic governor for an engine, characterized in that the dither width of the dither current increased to a predetermined value by the dither current superimposing means (6) is reduced based on the above. In the electronic governor of the engine according to claim 1 or 2,
The disturbance determination means (8) is linked to the rotation speed detection means (3),
The disturbance determination means (8) calculates a time difference Δt and an engine speed difference ΔR between adjacent peaks of the engine speed fluctuation, the time difference Δt is less than a predetermined time difference t, and the engine speed difference ΔR is a predetermined engine speed difference R. An engine electronic governor characterized in that when the number of times described above continues for a predetermined number n or more, the disturbance determination means (8) determines that the dither is a control disturbance.

Images