JP4247374B2 - Control method of fuel injection amount for marine engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for controlling the fuel injection amount of a marine engine.
[0002]
[Prior art]
The governor controller obtains information on the current engine speed, accelerator position, and rack position for adjusting the fuel injection amount, and controls the engine so as to obtain an appropriate engine speed. Here, droop control and isochronous control are conventionally used to adjust the fuel injection amount.
[0003]
Droop control is a control method in which when the engine is loaded, the fuel injection amount is increased while the engine speed is decreased according to the magnitude of the load. When droop control is used, the inertia of the hull is small. In the no-load region (below the two-dot chain line A in FIG. 2), the reduction amount of the engine speed with respect to the fuel injection amount is increased to prevent hunting, and the load region (the two points in FIG. On the upper side of the chain line A), the responsiveness of the boat speed to the accelerator insertion amount is improved by reducing the decrease amount of the engine speed with respect to the fuel injection amount.
[0004]
Isochronous control is a control method in which when a load is applied to the engine and the engine speed decreases, the engine speed is restored by the reduced amount and corrected to the original engine speed to maintain a constant engine speed.
[0005]
When isochronous control is implemented, the engine speed can be kept constant regardless of the load on the engine, but conversely, the operator can recognize whether the engine is currently loaded. For example, the load increases when a fish school hits the net on a fishing boat, but if the engine speed is kept constant by isochronous control, the ship operator visually confirms that the fish school has hit the net with an engine speed meter. Can not do it.
[0006]
Further, if the basic governor control (droop control) itself has a large gradient, that is, the gradients of the straight lines a, b, and d in FIG. In contrast, the engine speed does not converge with respect to load fluctuations, causing hunting.
[0007]
In this case, if the control cycle (for example, 5 ms) of basic governor control (droop control) is changed to the same as the control cycle (for example, 20 ms) of rotation speed correction control (isochronous control), hunting can be prevented, but engine acceleration and deceleration responses Sex worsens. From experience, it is not preferable to set the control period of droop control to a large value, because setting the control period of droop control to about 5 ms can exhibit responsiveness that the operator does not feel stress.
[0008]
[Problems to be solved by the invention]
In order to solve these problems, the present invention is similar to isochronous control in which when the engine is loaded, the amount of decrease in the engine speed is reduced more than when only droop control is performed, and hunting does not occur. An object is to provide a control method (hereinafter referred to as pseudo-isochronous control).
[0009]
[Means for Solving the Problems]
In the method for controlling the fuel injection amount of a marine engine that performs droop control in which the engine speed decreases from the engine speed at no load as the load increases, the load is reduced from the target engine speed set at no load. Calculates the target engine speed at load when the engine speed is reduced according to the load when applied, and the actual engine speed decreases according to the droop characteristic from the target engine speed at no load in the loaded state. Control is performed such that rotation speed correction control (isochronous control) for correcting the rotation speed is interrupted in the droop control so that the number becomes the target engine rotation speed at the time of load.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a signal transmission path of an electronic governor controller 1 used in a marine engine. In FIG. 1, the electronic governor controller 1 includes a CPU 11, an analog input circuit 12, a setting input circuit 13, a rotation speed input circuit 14, and a transistor output circuit 15.
[0011]
The accelerator sensor 3 detects the amount of accelerator insertion, and inputs an accelerator position detection signal to the CPU 11 via the analog input circuit 12. The rack position detection device 2 detects the position of the rack for adjusting the fuel injection amount, and inputs a rack position detection signal to the CPU 11 via the analog input circuit 12. The engine speed detection device 4 detects the engine speed and inputs an engine speed detection signal to the CPU 11 via the speed input circuit 14.
[0012]
The CPU 11 calculates the target engine speed at the time of load (for example, the engine speed N _{4 at} the point G on the broken line e in FIG. 2) from the accelerator position detection signal, and grasps it with the current engine speed (engine speed detection signal). For example, output is made to the rack actuator 5 via the transistor output circuit 15 so as to correct the difference from the engine speed N _{2 at} the point F on the solid line a in FIG. Adjust the amount.
[0013]
FIG. 2 is a graph showing the relationship between the fuel injection amount (rack position) to which the marine engine fuel injection amount control method of the present invention is applied and the engine speed. The broken line rising to the right is a plot of the engine speed and fuel injection amount (rack position) at no load (idle state). Hereinafter, the engine speed at no load will be referred to as idle speed.
[0014]
Now, a case where the engine is loaded when the idling speed is N ₁ will be considered with reference to FIG. In the idle state at the engine speed N ₁ o'clock, only one point E is determined. Based on a map (not shown) in which the ratio of reduction in engine speed with respect to a previously created combustion injection amount input to the CPU 11 (FIG. 1) is set, the load applied to the engine starting from this point E Only one solid line a is selected depending on the size of.
[0015]
The idle rotation speed (for example, N ₁ ) is calculated from an accelerator position detection signal detected by the accelerator sensor 3 (FIG. 1). Also, solid lines a and b that are drawn from the upper right broken line to the left are drawn. These solid lines a and b indicate the engine when the engine is loaded at idle speeds N ₁ and N ₆ , respectively. This is a plot of the relationship between the rotational speed and the rack position. A solid line a is defined by the engine speed N ₁ and a solid line b is a graph showing the droop control defined by the engine speed N ₆ .
[0016]
When the load at the time of idling speed N ₁ in loop control is applied, the engine speed becomes N _2. That is, the engine speed is reduced by (N ₁ −N ₂ ). When the load on the engine with respect to the this applied, there is isochronous control as a control method for automatically correcting the engine speed to the first N _1. The droop control shifts from the point E to the point F on the solid line a determined by the idle speed N ₁ , whereas the isochronous control shifts from the solid line a to the H point on the solid line d determined by the engine speed N _5. Let
[0017]
In FIG. 2, the graph parallel to the solid line a shows only the solid lines b and d, but there are innumerable rack position-engine speed graphs parallel to the solid line a and determined by the idle speed between the solid lines a and d. In these myriad graphs, the point H (engine speed: N ₁ ) is reached in a loaded state while shifting to the upper (right) graph. Of course, the rack position-engine speed graph parallel to the solid line a also exists other than between the solid lines a-d.
[0018]
In isochronous control, the amount of decrease in engine speed is used as the reference for calculating the rack position correction amount. Therefore, the calculated fuel correction amount is insufficient by the amount of time lag, and the corrected fuel injection amount The decrease cannot be corrected. Therefore, the load although the reduction of that amount engine speed is increased larger, the adjusting operation of the rack position to the engine speed converges to the target rotational speed is repeated, correcting the engine speed to N ₁ Can do.
[0019]
As described above, in the conventional isochronous control, when the engine speed is N ₁ (point E), the load increases and moves to point F along the solid line a, and the engine speed increases while increasing the fuel injection amount. When drops N _2, it is moved to the point H from point F on the graph. Point H is the engine speed N _1, the conventional isochronous control is maintained the engine speed N ₁ is set. However, in the marine engine fuel injection amount control method of the present invention, it returns to the point G ( the target engine speed at the time of load : N ₄ ) on the broken line e rising from the point E (the return process will be described later). The engine speed is intentionally reduced by (N ₁ −N ₄ ) than the engine speed N ₁ of the engine.
[0020]
That is, apart from the solid lines a, b and d indicating the droop control, an engine speed map (broken line e) corresponding to the load determined by the idle speed is set in advance and stored in the CPU 11 (FIG. 1). deep. Here, the broken line e shown in FIG. 2 exists not only for the point E of the engine speed N ₁ but also over the entire area (for example, the point Q) on the broken line showing the idle state in FIG.
[0021]
After transition from point E to point F by the loop control along the solid line a, increasing only the fuel injection amount while you are the engine speed N ₂ stable at point F, it reaches the point P in FIG. Point P is a point on the droop line defined by the idle speed N ₆ , and when the target engine speed is changed to R ₁ after moving to the point P, the load applied at the time of the idle speed N ₁ at point E at the beginning Therefore, the amount of fuel injection does not require the amount of fuel injection R ₁ , so that the engine speed changes from point P to point G along the solid line b, and the engine speed is N ₄ .
[0022]
In normal isochronous control, the engine speed is constant (maintains constant while being repeatedly corrected) with an increase in the fuel injection amount, and is on a line parallel to the vertical axis of FIG. 2 (engine speed is N ₁ ). In the present invention, the engine speed is controlled so as to decrease, for example, by Δn in FIG. 2 so as to shift on the broken line e having a negative slope. That is, as shown by a plurality of thin line arrows in FIG. 2, control is performed so as to exist on the broken line e like the point G and the point J through the point F and the point I.
[0023]
FIG. 3 is a flowchart showing the relative relationship between the two controls while separating basic governor control (droop control) and rotational speed correction control (pseudoisochronous control) with a broken line. Basically, droop control is performed at a control cycle of 5 ms, and pseudo-isochronous control is performed at a control cycle of 20 ms.
[0024]
First, the basic governor control (droop control) on the right side of FIG. 3 will be described. The actual rack position R ₃ is detected by the rack position detection sensor 2 (FIG. 1) and is input to the CPU 11 (FIG. 1). The CPU 11 (FIG. 1) determines the target engine speed based on the accelerator insertion amount input by the accelerator sensor 3. The number N ₁ is calculated, and the current engine speed N ₂ is input from the engine speed detector 4 to the CPU 11 (FIG. 1). These rack position R ₃ , target engine speed N ₁ , and engine speed N ₂ , the CPU 11 (FIG. 1) calculates the target rack position R ₁ by the following equation.
R ₁ = (N ₁ −N ₂ + ΔN) · D + R ₂
[0025]
Here, D is the absolute value of the slopes of the straight lines a, b and d (hereinafter referred to as the droop coefficient), and ΔN is the isochronous correction rotational speed. The rack is moved by the rack actuator 5 (FIG. 1) to the target rack position calculated by this calculation formula, and the fuel injection amount is controlled. This control is performed every 5 ms (control cycle 5 ms).
[0026]
Next, the rotation speed correction control (pseudo isochronous control) on the left side of FIG. 3 will be described. That is, a method for calculating ΔN will be described. First, the rack position R ₃ detected by the position detecting sensor 2 (FIG. 1) is input to the CPU 11, to calculate the rotational speed decrease amount Δn by the following equation.
Δn = (R ₃ −R ₂ ) / K _n
Wherein the R ₂ is rack position at point E (idle speed), and the K _n is the absolute value of the slope of the dashed line e, which is the engine rotational speed decrease amount gain.
[0027]
A value obtained by subtracting the rotation speed reduction amount Δn from the target engine speed N ₁ calculated from the detection signal detected from the accelerator sensor 3 is a target engine speed at the time of loading (a point on the broken line e in FIG. 2). If there is a difference from the actual rotational speed, the rotational speed correction amount ΔN is calculated by integrating the deviation.
[0028]
The rotational speed correction amount ΔN can be calculated by the following equation where the pseudo isochronous integral value (rotational speed correction amount) is N (n) and the pseudo isochronous gain is K _s .
ΔN = {(N ₁ −Δn−N ₂ ) + N (n−1)} · K _s
[0029]
If the magnitude of the load on the engine changes and the actual rotational speed changes, the above control is performed to adjust the rotation reduction amount according to the magnitude of the load. The above control can change the responsiveness at the time of load change by changing the control cycle. Further, by changing the engine speed decrease amount gain K _n, it can be set the engine speed decrease amount arbitrarily by changing a decrease amount gain engine speed by speed range or the like, freely engine load characteristic Can be set.
[0030]
【The invention's effect】
When the fuel injection amount control method of the present invention is applied, the decrease in engine speed can be reduced and hunting can be prevented as compared with the case where only droop control is performed, and the load on the hull is reduced in the load region. The ship operator can visually confirm that this has occurred by swinging the needle of the engine speed meter, which improves the maneuverability.
[0031]
The present invention is characterized in that the engine speed lowered along the solid lines a and b showing the droop control in FIG. 2 is improved by a predetermined amount and placed on a broken line e having a predetermined negative slope, By reducing the engine speed while carrying out isochronous control, it is possible to visually check with the engine speed meter that it is affected by waves and that a fish school has caught the net on a fishing boat. It can be carried out.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an electronic governor controller of a marine engine.
FIG. 2 is a graph showing the relationship between the fuel injection amount and the engine speed.
FIG. 3 is a flowchart of a method for controlling the fuel injection amount of a marine engine according to the present invention.
[Explanation of symbols]
4 Engine speed detector

Claims (1)

In the method for controlling the fuel injection amount of a marine engine that performs droop control in which the engine speed decreases from the engine speed at no load as the load increases,
Target engine speed (N ₁ ) To load (R ₃ -R ₂ ) Is applied, the rotational speed reduction amount (Δn = N ₁ -N ₄ ), The target engine speed at load (N ₄ )
The target engine speed (N ₁ ) From the actual engine speed (N ₂ ) For the target engine speed (N ₄ ) So that the rotational speed is corrected (ΔN = N ₄ -N ₂ A control method for controlling the fuel injection amount of the marine engine, wherein control for interrupting the rotational speed correction control (isochronous control) to be performed in the droop control is performed.

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