JPS6342108B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to improvements in speed governors for internal combustion engines.

Conventional diesel engines have mainly used jerk-type fuel injection pumps, which use a fuel cam to move a plunger up and down to increase the pressure of the fuel and send it to the injection valves.

The main part is shown in Figure 1, and the fuel passes through the port 02 provided in the barrel 01 to the plunger 0.
3. Enters the upper part, becomes highly pressurized, and is sent to the injection valve. When the plunger 03 rises to a certain height, the groove 04 of the plunger and the port 02 overlap, and the pressure in the plunger chamber escapes to the port, ending the discharge of the pump. This plunger groove 04 influences the injection characteristics of the engine, and is designed for each engine and has various shapes.

FIG. 2 shows an example of the shape and the corresponding injection amount characteristics. a is the simplest shape,
b is used to improve characteristics in the low rotation (low load) region. On the other hand, recent diesel engines have been designed to achieve lower fuel consumption in order to save energy, and one effective means of achieving this is to increase the pressure inside the cylinder. Therefore, a method of increasing the cylinder pressure under normal load up to the pressure limit value of the maximum continuous load of the engine is actively adopted, and the type c is put into practical use.

However, in the shapes b and c, as shown in the injection quantity characteristics, the relationship between the stroke S (pump rack scale) on the horizontal axis and the injection quantity Q on the vertical axis is not constant, resulting in a change in the Q/S ratio. Become.

On the other hand, the governor, which is installed to keep the engine speed constant, is used to adjust the amount of fuel, and it detects the deviation between the setting and the actual speed and compensates for the stroke S. There is.

Here, in the conventional one, (1) The compensation characteristic of the speed governor is one mode that is optimally set, and the output mode (change in stroke S) is constant for the rotational speed deviation amount Δn. However, in shapes b and c, even if the governor output (stroke S) is constant, the Q/S ratio of the plunger is different, resulting in a large difference in the amount of change in the injection amount Q. . That is, a change in speed control performance occurs at a point where Q/S changes.

(2) In general, the speed governor settings are made to be optimal for regular operation, so at low loads with a small injection amount, the settings will not match, resulting in a hunting state where the rotation speed does not stabilize. This causes frequency fluctuations in power generating engines, causing major problems. At the same time, in the power generating engine, the characteristics at the time of load on and off will change depending on the injection amount characteristics.

(3) It is possible to optimize the speed governor settings by changing the speed governor settings each time, but this operation is extremely complicated. Furthermore, since hunting is accompanied by excessive fluctuations in the fuel amount setting mechanism, it causes backlash or premature abnormal wear of the setting mechanism.

The purpose of the present invention is to solve problems in the adjustment performance of engines equipped with fuel injection pumps that have specially shaped plungers, which have been recently adopted as a means of reducing fuel consumption, and to reduce rotational speed (frequency) fluctuations as much as possible. Our goal is to provide a speed governor that can improve maneuverability as a land-use, low-consumption engine, and its features include a fuel injection pump that has multiple injection modes with different injection amounts and pump rack stroke ratios. In a speed governor for an internal combustion engine, a rotation speed comparator receives the set rotation speed and actual rotation speed and detects the rotation speed deviation, a fuel position transmitter detects the stroke of the pump rack, and a signal from the fuel position transmitter. a discriminator that discriminates the injection mode by;
A certifying device receives the signals of the rotational speed deviation amount and the injection mode and corrects the rotational speed deviation amount in accordance with the same injection mode; The present invention includes a controller that sets the stroke increase/decrease in the injection mode, and an actuator that transmits the stroke increase/decrease to the pump rack based on a signal from the controller.

In this case, the characteristics of the fuel injection pump and speed governor are analyzed together, and the settings of the speed governor are automatically compensated according to the pump characteristics to achieve optimal speed control performance over the entire operating range of the engine. can be realized.

Furthermore, fluctuations in rotational speed when switching settings can be minimized.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is an explanatory diagram showing one embodiment of the apparatus according to the present invention.

In the figure, 1 is a rotation speed comparator, 2 is a controller, 3 is an actuator (fuel amount setting device), and 4
5 is a fuel injection pump, 5 is a rotation speed transmitter, 6 is a fuel position transmitter, 7 is a mode discriminator, and 8 is a corrector. Note that 11 is a gear train, 12 is a camshaft, and 13 is a cam.

In conventional speed regulation, when the rotation speed comparator 1 compares the set rotation speed with the actual rotation speed detected by the rotation speed transmitter 5 and a deviation amount Δn occurs, the controller 2 adjusts the response speed. Compensation is performed to increase or decrease the amount of fuel in the fuel injection pump 4 via the actuator 3.

In a mechanical-hydraulic speed governor, the functions of members 1, 2, 3, and 5 are built-in.

In the present invention, the fuel position transmitter 6 is included in the speed governing system.
A mode discriminator 7 and a corrector 8 are newly provided.

The stroke position signal of the pump rack of the fuel injection pump detected by the fuel position transmitter 6 is calculated by the modifier 8 via the mode discriminator 7, and the settings of the controller 2 are automatically optimized.

Further, the corrector 8 always checks the signal from the rotational speed comparator 1 and switches the controller 2 only at a specific timing, thereby preventing rotational speed fluctuations that would be expected at the time of switching.

In the conventional system, when the rotation speed comparator 1 detects the deviation amount Δn as shown in FIG. 4a, the output of the controller 2 becomes as shown in FIG. Ratio Q/S
Due to the characteristics of , a change like the two modes shown in c in the same figure will occur. As a result, the matching of the speed governing system changes, causing rotational speed fluctuations.

According to the present invention, the mode discriminator 7
By detecting a change in the S characteristic and using the controller 2 via the corrector 8 to modify Δn ₀ =Δn×α×β or G(S) ₀ =G(S)×α×β, the engine This makes it possible to ensure optimal speed control performance over the entire operating range.

Here, Δn ₀ and Δn are the rotational speed deviation amounts after compensation and the original, G(S) ₀ and G(S) are the governor transfer functions after compensation and the original, α is the correction coefficient obtained from the Q/S characteristic, β is a correction coefficient determined from driving characteristics.

Normally, β can be ignored, but it is necessary to make corrections especially when suppressing rotational speed fluctuations, such as during rapid reversal operations when a marine vessel has a main engine-driven generator.

On the other hand, if the controller 2 is switched while the speed (or load) is stable, a wide change in speed will occur.

Therefore, in principle, the switching is performed instantaneously when the mode of the mode discriminator 7 changes and a deviation amount occurs in the rotational speed comparator 1. For example, when a marine engine is in an accelerated state, even if the speed setting is increased by operating the steering wheel, it takes time for the vessel to accelerate, so the set rotational speed is not reached immediately and fuel is injected to a level allowed by the engine. In other words, in this state, there is more fuel than is in balance with the set rotation speed,
Even if the settings of the controller 2 are changed at this time, no speed change will occur.

Conversely, in a deceleration state, the fuel is 0 while there is a rotational speed deviation amount, resulting in the same result.

Furthermore, when the speed is set at the mode switching point, the switching of the controller 2 is repeated, but when the switching is repeated for a certain period of time, a setting with good speed regulation is maintained, and when a certain period of time has elapsed, the switching circuit is turned on again. I'm trying to make it work.

Note that although the present invention is a device for switching with one controller, there is a patent application No. 1988-88622 entitled "Governing System" for switching between two controllers.
It is also possible to use this method.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the main parts of the fuel injection pump;
Figures 2a, b, and c are explanatory diagrams showing the reed shape and injection amount characteristics of the fuel injection pump, respectively; Figure 3 is an explanatory diagram showing the device according to the present invention; Figure 4a is an explanatory diagram showing the governor input; FIG. 4b is a diagram showing the governor output, and FIG. 4c is a diagram showing the injection amount Q. 1...Rotation speed comparator, 2...Controller, 3
... Actuator, 4 ... Fuel injection pump, 5
...Rotational speed transmitter, 6...Fuel position transmitter, 7...
...mode discriminator, 8...corrector.

Claims (1)

[Claims] 1. In a speed governor for an internal combustion engine equipped with a fuel injection pump having a plurality of injection modes with different injection amounts and pump rack stroke ratios, a rotation speed comparator that receives a set rotation speed and an actual rotation speed and detects a rotation speed deviation amount. , a fuel position transmitter that detects the stroke of the pump rack, a mode discriminator that determines the injection mode based on the signal from the fuel position transmitter, and a mode discriminator that receives the rotational speed deviation amount and the injection mode signal to correspond to the injection mode. a controller that sets an increase/decrease of the stroke in the injection mode in response to the corrected rotational speed deviation from the corrector; A speed governor for an internal combustion engine, comprising an actuator that transmits an increase or decrease to a pump rack.