JPH0154534B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cylinder number control device for a diesel engine, and more specifically, to a device for controlling the number of cylinders in a multi-cylinder diesel engine, which stops the operation of some cylinders when the load of the multi-cylinder diesel engine is small. The present invention relates to a cylinder number control device for a diesel engine that can improve fuel efficiency and reduce unburned HC (hydrocarbons) by reducing engine friction loss.

[Prior Art] Originally, diesel engines do not have means for restricting the amount of intake air, so from no-load operation to full-load operation, a large amount of air is sucked in, compressed, and exhausted.

The amount of work required for this is enormous, and nearly half of the total friction loss in a diesel engine occurs during the compression and exhaust strokes. In particular, when a diesel engine is operated at low load, the ratio of friction loss to the net work of the engine increases. Conventionally, when a diesel engine is operated at low load, in order to reduce the friction loss that occurs during the compression and exhaust strokes, so-called pumping loss,
There are attempts to reduce the amount of intake air.

However, in conventional diesel engine systems, simply reducing the amount of intake air to significantly reduce pumping loss results in an increase in hydrocarbons (HC), poor startability, and blue-white smoke. The above-mentioned attempts have not yet been put to practical use because of problems such as increased

In addition, in a normal in-line diesel engine, there is only one fuel injection pump, and the amount of fuel injected to each cylinder is the same, so the amount of fuel injected to each cylinder can be changed during engine operation. I couldn't.

Therefore, when the engine is operated at low load, an intake throttle valve is provided in the intake passage to some cylinders, and the throttle valve is closed when the operation of the certain cylinder is stopped. There is an idea in Publication No. 55-161034. In this prior art, negative pressure is introduced into the diaphragm device by operating a solenoid valve using a load switch that is turned on when the engine load is a predetermined value, for example, when the accelerator pedal depression is 1/2 or less, or A solenoid device is used to close the intake throttle valve and cut off fuel supply to the cylinder.

Further, as a means for stopping the fuel supply to the idle cylinder, a switching valve is provided which bypasses the fuel supplied to the fuel injection valve and releases the fuel.
There is an invention in Publication No. 13825. This prior art fuel relief valve discloses means for opening and closing the relief valve by bringing a male thread that drives the valve body into contact with a valve body that is biased in a closing direction, and rotating the male screw with a lever. There is.

In addition, the fuel cutoff solenoid valve was installed in each fuel suction hole of a parallel type fuel injection pump.
There is an idea in Publication No. 122220.

[Problems to be Solved by the Invention] However, in all of the above three prior arts, the engine output is discontinuous because some cylinders are stopped when the engine load reaches a predetermined value. There is a danger that it will change.

Therefore, there is an invention disclosed in Japanese Patent Application Laid-open No. 114819/1983 in which the output of an engine that supplies fuel to the intake pipe is changed continuously when switching to reduced cylinder operation. According to the description in the same publication, this prior art is capable of cutting off the fuel supply by interposing a valve in the fuel passage of an engine operating with reduced cylinders, and also by providing a throttle valve in the intake pipe, so that the fuel The output can be changed continuously when the number of cylinders is changed by opening/closing the intake pipe throttle valve and adjusting the opening degree of the intake pipe throttle valve.

According to the example of the publication, 4 cylinders, 6 cylinders,
When changing the number of cylinders to 8 cylinders, close the fuel valve of the idle cylinder and adjust the opening of the intake throttle valve to match the engine speed to 0 to 90 degrees for 4 cylinders and 30 to 90 degrees for 6 cylinders. , discloses means for controlling the angle between 60 and 90 degrees for eight cylinders. In other words, this prior art opens and closes the fuel passages that supply fuel to the idle cylinders, limits the intake throttle range to a specific range according to the number of cylinders, and furthermore, when changing the number of cylinders, the throttle amount is suddenly increased. By changing the output, continuity of the output can be obtained.

Therefore, as mentioned above, the intake throttle valve requires an extremely complicated structure and operation, and the adjustment and maintenance of the engine is also complicated. Further, when the number of cylinders is changed, if the intake air amount is suddenly reduced, there is a risk of deteriorating the combustion state, which is not preferable. Moreover, in the case of a diesel engine, it is difficult to adjust the output by throttling the intake air.

Therefore, the present invention has been made by focusing on the above-mentioned problem, and in the reduced cylinder operation when the load detection value of the diesel engine is less than the set value, the intake cutoff valve and the exhaust cutoff valve of some cylinders are closed simultaneously. , by blocking air intake from the intake system and the exhaust system to reduce pumping loss of the engine and improve fuel efficiency, and by cutting off fuel in the cylinder using a fuel release amount adjustment valve during the cylinder reduction operation, The fuel efficiency rate is further improved, and the amount of hydrocarbon (HC) in the exhaust gas is also reduced to improve the exhaust purification rate.Furthermore, in the reduced cylinder operation, the cylinders other than the cylinders that do not stop are distributed type. By operating the fuel injection pump, the amount of fuel discharged is maximized and the engine is operated at high output, thereby improving the combustion efficiency of the engine.In addition, in high-load operation exceeding the set value,
It is possible to increase the engine output by supplying fuel according to the load that increases from the set value while maintaining the maximum output of the cylinders that have not been shut down during low-load operation, thereby further improving the combustion efficiency of the engine. ,moreover,
The cylinder number control device has the regulating valve built into the distribution type fuel injection pump, so that the regulating valve instantaneously shuts off and opens the fuel return passage and the chamber chamber, thereby controlling the number of engine cylinders in response to changes in the number of operating cylinders. The purpose of this invention is to provide a cylinder number control device for a diesel engine that can improve driving response.

[Means for solving the problems] In order to achieve the above object, the configuration of the present invention is as follows:
A distribution type fuel injection pump which incorporates a load detection means and a fuel relief amount adjustment valve for some cylinders, and maximizes the discharge amount when the detected value of the load detection means reaches a set value; When the detected value is less than or equal to a set value, both of the shutoff valves are closed and the regulating valve is opened, and when the detected value exceeds the set value, both of the shutoff valves are opened and the load is increased from the set value. The present invention provides a cylinder number control device for a diesel engine, comprising a control means for throttling the regulating valve according to the number of cylinders of the diesel engine.

[Function] The function of the diesel engine cylinder number control device of the present invention having the above configuration is as follows.

First, since the amount of depression of the accelerator pedal is small until the engine load reaches the set value, the fuel relief amount adjustment valve is in a fully open state, and all the fuel injected to the partial cylinder flows to the fuel return passage, Fuel is not supplied to the fuel injection nozzles of some cylinders. Furthermore, the intake cutoff valve and the exhaust cutoff valve are fully closed by the operation of the control means.

Next, the amount of depression of the accelerator pedal increases,
When the engine load reaches the set value, the cylinders other than the above-mentioned partial cylinders are in a full load state, but the load on the engine as a whole is reduced to 1/2.

When the engine load exceeds the set value, the fuel escape amount adjusting valve moves in a direction to close the passage to the fuel return passage, and fuel is gradually supplied to the some cylinders. At the same time, the intake cutoff valve and the exhaust cutoff valve are fully opened by the operation of the control means, and the operation of the partial cylinders is started. moreover,
When the accelerator pedal is depressed, the fuel release amount adjusting valve is fully closed, and the full amount of fuel injection from the fuel injection pump is supplied to the partial cylinders. During this time, the cylinders other than the above-mentioned partial cylinders are always operated at full load, and the diesel engine can obtain maximum output when the above-mentioned fuel relief amount adjusting valve is fully closed. When the accelerator pedal is released, the engine returns to reduced cylinder operation in the exact opposite order.

As described above, according to the cylinder number control device for a diesel engine of the present invention, when the engine load is from idle to a set value, the air intake, fuel, and exhaust are simultaneously shut off for the partial cylinders of the diesel engine;
Only the cylinders other than the above-mentioned part are operated. Therefore, since the pumping loss of the partial cylinders disappears when the engine load is from idle to the set value, the friction loss of the engine is significantly reduced compared to a conventional diesel engine.

For this reason, diesel engines for passenger cars, which are frequently used especially in low load ranges, have significantly improved fuel efficiency compared to conventional engines.

Additionally, when the load is low, the amount of hydrocarbons (HC) in the exhaust generally increases rapidly, but the load on the cylinders other than the above-mentioned cylinders that are operating increases relatively compared to a typical diesel engine. Since it is operated outside the HC rapid increase range and the amount of exhaust gas is halved, it is possible to reduce the HC concentration in the exhaust gas as a whole.

[Example] Hereinafter, an example of the present invention will be described using the drawings.

FIG. 1 is an overall configuration diagram of a cylinder number control device for a diesel engine showing one embodiment of the present invention;
A four-cylinder diesel engine comprising a first cylinder #1, a second cylinder #2, a third cylinder #3, and a fourth cylinder #4,
2 is an intake manifold, 4 is a distribution type fuel injection pump, 5 is a fuel injection nozzle provided for each cylinder of the engine, and 12 and 13 are interlocked with the accelerator pedal 11 to adjust the amount of fuel injected from the fuel injection pump 4. It is a control lever.

The second and third cylinders #2, #2 of the fuel injection pump 4 can stop the supply of fuel to the second cylinder #2 and third cylinder #3 of the four-cylinder diesel engine 1.
A fuel escape amount adjusting valve 6 is built in the middle of the fuel return passage 23 communicating with the fuel pressure feeding passage 4f to #3, and an intake cutoff valve 3 is provided in the intake manifold 2 of the second and third cylinders, Intake air to the cylinders can also be shut off, and an exhaust manifold 27 is also provided with an exhaust shutoff valve 28, so that exhaust air from the cylinders can also be shut off.

The structure of the distribution type fuel injection pump 4 incorporating the fuel relief amount adjusting valve 6 is as shown in FIGS. One plunger 4e that reciprocates by the action of a disk 4d
The fuel is distributed through the fuel pressure passage 4f of each cylinder, passes through the delivery valve 4g, and is injected from the fuel injection nozzle 5 of each cylinder.

Spill ring 4 adjusts this fuel injection amount.
h, which is connected to said control lever 12 via an intermediate link 4k.

In the present invention, a fuel return passage 23 is provided which communicates with the fuel pressure feeding passage 4f of the second and third cylinders #2 and #3 of the fuel injection pump 4 configured as described above and the chamber chamber 4b, and the fuel return passage 23 is provided in the middle thereof. A relief amount adjustment valve 6 is provided.

This fuel release amount adjusting valve 6 is rotated by a spill control lever 18 to control the fuel return passage 2.
The spill control lever 18 is connected to the control lever 13 by a link 24. The operations of the control levers 12, 13 and the cancel spring 17 will be described later.

As shown in Figures 2 and 3, the fuel release amount adjustment valve 6
When the fuel return passage 23 is closed, the fuel pumped by the plunger 4e is supplied to the fuel injection nozzle 5 from any fuel pressure passage 4f, but the spill control lever 18 rotates and the fuel return passage 23 is opened. When the cylinder is opened, the fuel pumped to the second and third cylinders is returned to the chamber chamber 4b from the fuel return passage 23 depending on the opening amount. Therefore, when the fuel escape amount adjusting valve 6 fully opens the fuel return passage 23, the entire amount of fuel that is force-fed to the second and third cylinders returns to the chamber chamber 4b, and no fuel is injected from the fuel injection nozzle 5.

As shown in FIG. 1, the spill control lever 18 is connected to the control lever 13 of the fuel injection pump 4 by a link 24, and rotates when the control lever 13 exceeds a set rotation angle indicated by a chain line C. However, the maximum rotation angle and the reference position are defined by the zero spill limiter 19 and the maximum spill limiter 20. 21 is a return spring.

In the present invention, the control lever that controls the fuel injection amount of the fuel injection pump 4 is a control lever 12 that controls the fuel injection amount of the first and fourth cylinders #1 and #4, and a control lever that controls the fuel injection amount of the second and third cylinders #2 and #3. The control lever 13 controls the fuel injection amount by the fuel release amount adjustment valve 6, and both control levers 12 and 13 are separated by a cancel spring 1.
7.

When the accelerator pedal 11 is not depressed, the levers 12 and 13 are kept stationary at the position shown in FIG. 1 by a return spring 14 and an idle stopper 16. 15 is a full load stopper for the control lever 12.

The configuration of the fuel control system of the present invention has been described above. Next, the configuration of the intake air amount control system provided in the intake manifold 2 will be explained in detail.

The intake cutoff valve 3 provided in the intake manifold 2 of the second and third cylinders is connected to a link 25 by a lever 26, and when this link 25 is attracted by the solenoid 9, it moves in the direction of arrow E and moves the lever 26 to F. The intake valve 3 is rotated as shown in FIG. The solenoid 9 sucks the link 25 when the relay 8 is turned on, and the relay 8 sucks while the movable contact 7a of the exhaust cutoff valve on/off switch 7 is pressed by the spill control lever 18 and is in contact with the fixed contact 7b. It is now only turned on. 10 is boring.

Next, the configuration of the exhaust amount control system provided in the exhaust manifold 27 will be explained in detail.

The exhaust cutoff valve 28 provided in the exhaust manifold 27 of the second and third cylinders is connected to the lever 29 and the link 2.
5a is connected to the link 25, and this link 25 moves in the direction of arrow E when it is attracted by the solenoid 9, rotates the lever 26 as shown in F, opens the exhaust cutoff valve 28, and directs the exhaust gas to the second , the engine is designed to emit more air from the 3rd cylinder.

The cylinder number control device for a diesel engine according to the present invention is constructed as described above.Next, the cylinder number control operation of this cylinder number control device will be explained.

First, the load condition of the engine is set as the full load as 1, and half of it is expressed as 1/2, and the set value of the load condition for controlling the number of cylinders is set as 1/2 of the full load, and the control lever 12 at this time is , 13 is indicated by the dashed line C
If the position is , the amount of depression of the accelerator pedal 11 is small from the idle state to 1/2 load, so the control lever 1 of the fuel injection pump 4 is
2 and 13 rotate together between lever positions B and C shown by chain lines, but link 24 does not move. At this time, the plunger 4e of the fuel injection pump 4
The same amount of fuel is injected to all cylinders, but as mentioned above, the link 24 does not apply force to the spill control lever 18, so the fuel relief amount adjusting valve 6 is in the fully open state, and the second and third Cylinder #2, #3
All the fuel injected into the cylinder flows into the fuel return passage 23, and no fuel is supplied to the fuel injection nozzles 5 of the second and third cylinders.

Also, at this time, the intake and exhaust shutoff valve on/off switch 7
is in the off state, so the relay 8 and solenoid 9 are not operated, and the intake cutoff valve 3 and the exhaust cutoff valve 28 are in the fully closed state.

Next, when the amount of depression of the accelerator pedal 11 increases further, the control lever 12 for the first and fourth cylinders hits the full load stopper 15 and will no longer rotate. At this time, the first and fourth cylinders are under full load, but the load on the engine as a whole is 1/2.
It is becoming.

However, until now, cancel spring 17
The control levers 13 for the second and third cylinders, which used to rotate together with the control lever 13 due to the action of You can continue as is,
When the set rotation angle shown by chain line C is exceeded, link 24
Rotate the spill control lever 18 via the .

Therefore, as the rotation angle of the spill control lever 18 increases, the fuel escape amount adjusting valve 6 moves in the direction of closing the passage to the fuel return passage 23, and the second,
Fuel is gradually supplied to the three cylinders.
At the same time, the intake and exhaust shutoff valve on/off switch 7 is turned on, and the battery 1 is sent to the solenoid 9 via the relay 8.
0 is connected, the links 25, 25a are attracted, the levers 26, 29 are rotated in the direction F in the figure, and the intake cutoff valve 3 and the exhaust cutoff valve 28 are fully opened.
The operation of the second and third cylinders is started. When the accelerator pedal 11 is further depressed, the spill control lever 18 hits the zero spill limiter 19 and will no longer rotate.

At this time, the fuel release amount adjustment valve 6 is fully closed.
The entire amount of fuel injected by the fuel injection pump 4 is supplied to the second and third cylinders. During this time, the first and fourth cylinders are always operated at full load, and the diesel engine 1 of the present invention can obtain maximum output with the fuel release amount regulating valve 6 fully closed. When the accelerator pedal 11 is released, the engine returns to the reduced cylinder operating state in the completely reverse order.

As described above, according to the diesel engine cylinder number control device of the present invention, from idle (no load) to 1/2 load, the intake air, fuel, and exhaust air of the second and third cylinders of the diesel engine 1 are simultaneously shut off. Only the first and fourth cylinders are in operation. Therefore, from idle to 1/2 load, there is no pumping loss in the second and third cylinders, so as shown by the solid line in Figure 4, the friction loss of the engine is significantly greater than that of a conventional diesel engine shown by the broken line. decreases to

For this reason, diesel engines for passenger cars, which are frequently used especially in the low load range, have significantly improved fuel efficiency, as shown by the solid line in FIG. 5, compared to conventional engines shown by the broken line.

Additionally, when the load is low, the amount of hydrocarbons (HC) in the exhaust generally increases rapidly, but the load on the operating No. 1 and 4 cylinders increases relatively compared to a typical diesel engine, and the HC increases rapidly. In addition to being operated in a region outside the normal range, the amount of exhaust gas is also reduced to 1/2, so overall, as shown in Figure 6, the present invention is shown by the solid line, and the conventional system is shown by the broken line, which makes it possible to reduce the HC concentration in the exhaust gas. can.

In the above embodiment, a case has been described in which the operation of two of the four cylinders is stopped at low load, but depending on the difference in load conditions, it is also possible to easily stop the operation of only one cylinder.

Further, in the case of a three-cylinder or six-cylinder diesel engine, the present invention can be easily implemented even if the number of cylinders is different, such as stopping operation of appropriate plural cylinders.

[Effects of the Invention] As described above, the diesel engine cylinder number control device of the present invention incorporates a load detection means and a fuel relief amount adjustment valve for some cylinders, and the detection value of the load detection means is set. a distribution type fuel injection pump that maximizes the discharge amount when a value is reached; an intake and exhaust cutoff valve for the cylinder; and when the detected value is less than a set value, both the cutoff valves are closed and the regulating valve is opened. , when the set value is exceeded, the control means opens both of the shutoff valves and throttles the regulating valve according to the amount of increase in load from the set value, so that reduced cylinder operation is performed when the detected load value is less than the set value. In this case, by simultaneously closing the intake cutoff valve and exhaust cutoff valve of some cylinders, air intake from the intake system and exhaust system is prevented, the pumping loss of the engine is reduced, the fuel efficiency is improved, and the reduced cylinder During operation, by cutting off the fuel in the cylinder using the fuel release amount adjustment valve, the fuel efficiency is further improved, and the amount of hydrocarbon (HC) discharged in the exhaust is also reduced, thereby improving the exhaust purification rate. Furthermore, in the reduced-cylinder operation, the cylinders other than the cylinders that do not stop are operated at a high output with the maximum amount of fuel discharged by the operation of the distributed fuel injection pump, thereby improving the combustion efficiency of the engine. ,
In addition, during high-load operation exceeding the set value, engine output is increased by supplying fuel according to the load increasing from the set value, while maintaining the maximum output of the cylinders that were not shut down during low-load operation. , the combustion efficiency of the engine can be further improved, and furthermore, the cylinder number control device incorporates the regulating valve in the distribution fuel injection pump, thereby controlling the connection between the fuel return passage and the chamber chamber by the regulating valve. Shutdown and opening can be performed instantaneously, and the response of engine operation to changes in the number of operating cylinders can be improved.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of a cylinder number control device for a diesel engine according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a distribution type fuel injection pump incorporating the fuel relief amount adjusting valve of FIG. 1, and FIG. The figure is a cross-sectional view taken along the line A-A in Figure 2, and Figures 4 to 6 are diagrams showing a performance comparison between the diesel engine of the present invention and a conventional diesel engine, and Figure 4 shows the rotation speed and friction. Figure 5 shows the relationship between load conditions and fuel efficiency, Figure 6 shows the relationship between load conditions and HC concentration, and Figure 7 shows the intake system and exhaust system of the diesel engine in the above example. FIG. 1... Diesel engine, 2... Intake manifold, 3... Intake cutoff valve, 4... Fuel injection pump,
5...Fuel injection nozzle, 6...Fuel release amount adjustment valve, 7...Suction/exhaust cutoff valve on/off switch, 8...
Relay, 9... Solenoid, 11... Accelerator pedal, 12, 13... Control lever, 18
...Spill control lever, 22, 22'...
...Fuel injection pipe, 23...Fuel return passage, 25,2
5a...Link, 26, 29...Lever, 28...
...Exhaust shutoff valve.

Claims (1)

[Claims] 1. A distribution fuel injection pump which incorporates a load detection means and a fuel relief amount adjustment valve for some cylinders, and which maximizes the discharge amount when the detected value of the load detection means reaches a set value; , an exhaust cutoff valve, and when the detected value is less than a set value, both the cutoff valves are closed and the regulating valve is opened, and when the detected value exceeds the set value, both the cutoff valves are opened and the load is increased from the set value. A control device for controlling the number of cylinders of a diesel engine, comprising a control means for throttling the regulating valve in accordance with the amount of the control valve.