JPH0232821Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a resonant supercharging control device for a diesel engine.

Some diesel engines employ resonance supercharging to increase the efficiency of air filling in each cylinder.

Resonant supercharging is a method that matches the frequency of the air column vibration in a resonance pipe formed in a part of the intake manifold with the frequency of the intake pulsation that occurs when the intake valve opens and closes, and uses this resonance to push a large amount of intake air into the cylinder. be.

Conventionally, there is a resonance supercharging device constructed as shown in FIG. 1, for example (Japanese Utility Model Application No. 57-92021).

Resonance pipes 9 and 10 are connected to cylinders #1 to #3 and #4 to #6, whose intake valve opening timings do not overlap with each other, via confluence portions 7 and 8, respectively.

A passage 11 is formed that communicates the merging parts 7 and 8, and a valve 12 that closes in a high engine load range and opens in a low engine load range is interposed in the passage 11.

Reference numeral 13 denotes a fuel injection device, and by detecting the angle of a load lever of this fuel injection device, a signal is generated to close the valve 12 when the engine load exceeds a set value.

Therefore, in the engine high load range, valve 12
blocks the communication path 11 between the merging portions 7 and 8, so that resonance supercharging is performed centering on the region where the air column frequency of each resonance tube 9 and 10 and the frequency of the intake pulsation match.

In other words, a large amount of fuel is injected in a high engine load range, but resonance supercharging ensures an amount of intake air commensurate with the increase in fuel.

On the other hand, in a low engine load range, the valve 12 opens the passage 11 of the merging sections 7 and 8, and the intake valve opening timings of cylinder groups #1 to #3 and #4 overlap.
~ #6 are communicated.

Therefore, the intake pulsations of the cylinder groups #1 to #3 and the intake pulsations of the cylinder groups #4 to #6 interfere with each other, and as a result, a resonance phenomenon cannot be obtained, and resonance supercharging is stopped.

In other words, resonance supercharging is stopped in a low engine speed range where the fuel injection amount is small, thereby avoiding an increase in pumping loss due to excessive intake.

Note that resonance supercharging cannot achieve good supercharging except in an extremely limited engine rotation range where the air column frequency of the resonance pipes 7 and 8 and the frequency of the intake pulsation match.

In addition, a structure as shown in FIG. 2 has been proposed in which the engine rotational speed is increased so that resonance supercharging can be performed satisfactorily (Japanese Patent Application Laid-Open No. 115818/1983).

In this case, resonance pipes 9 and 10 connected to cylinders #1 to #3 and #4 to #6, whose intake valve opening timings do not overlap, through merging portions 7 and 8, respectively, merge on the upstream side.

In addition, resonance pipes 9 and 10 are cylinder groups #1 to #3 and #4.
~The frequency of the air column from #6 to the upstream merging portion 14 via the downstream merging portions 7 and 8 is the frequency of the intake pulsation in the low engine speed range, and the cylinder groups #1 to #3 and #4 The frequency of the air column from #6 to the downstream merging portions 7 and 8 is formed to match the frequency of the intake pulsation in the engine high rotation range.

A valve 12 is interposed in a passage 11 that communicates the merging parts 7 and 8 on the downstream side, which closes in a low engine speed range and opens when the engine speed exceeds a set value.

According to this, in the low engine speed range where the valve 12 is closed, the air column portions of the resonance pipes 7 and 8 from the cylinder groups #1 to #3 and #4 to #6 to the upstream merging section 14, and the valve 12 In the high engine speed range where the
Resonance in the air column portions of the resonance pipes 9 and 10 extending from the cylinder groups #1 to #3 and #4 to #6 to the merging portions 7 and 8 on the downstream side provides the effect of supercharging.

By the way, FIG. 3 is a comparison diagram of equal fuel consumption curves based on experimental data for supercharging using only a turbo supercharger and when resonant supercharging is added to supercharging using a turbo supercharger.

In the figure, the dotted line A shows an equal fuel consumption curve when supercharging is performed only with a turbo supercharger, and the solid line B shows an equal fuel efficiency curve when resonance supercharging is added to the supercharging of the turbo supercharger.

As is clear from this figure, the cross point between the equal fuel consumption curve A for only turbocharging and the equal fuel consumption curve B for the case where resonance supercharging is performed in addition to the turbocharger supercharging. In the operating region above the curve C that connects the curve C, adding resonance supercharging to the supercharging of the turbocharger results in better fuel efficiency; in the operating region below the curve C, however, it is better to It's more fuel efficient.

However, even in the operating range below curve C, in the low speed and high load range, supercharging using only a turbo supercharger results in worse fuel efficiency.

Note that a curve C connecting the cross points of both equal fuel consumption curves A and B substantially coincides with the equal boost curve.

This idea focused on this point, and the resonance pipes, which are connected to multiple cylinders whose intake pulp valve opening timings do not overlap with each other through a merging section, are merged upstream of each other, and a turbo supercharger is installed upstream of the merging section. In a diesel engine equipped with this, a passage is formed that connects the converging parts on the downstream side of the resonance tubes with each other, and a valve that opens only when the boost pressure is below a set value based on the boost pressure downstream of the turbocharger is installed in this passage. ,
This diesel engine is equipped with a valve that opens only when the load is below a set value based on the engine load, and controls resonance supercharging based on boost pressure and engine load, improving fuel efficiency over the entire range of motion. The purpose is to provide a resonance supercharging control device for engines.

This invention will be explained below with reference to the embodiment shown in FIG. Note that the same reference numerals are used for the same parts as in FIGS. 1 and 2.

Reference numerals 9 and 10 indicate resonance pipes, and the resonance pipes 9 and 10 connect cylinders #1 to #3 and #4 to cylinders #1 to #3 and #4 to
Connected to #6.

The resonance pipes 9 and 10 join on the upstream side, and a turbo supercharger 16 is installed upstream of the joining part 15.

The turbo supercharger 16 supercharges the cylinders #1 to #6 from the resonance pipes 9 and 10 via the merging section 15 in accordance with the engine speed.

A passage 11 is formed which communicates the confluence parts 7 and 8 on the downstream side of the resonance tubes 9 and 10, and two valves 17 and 18 are interposed in this passage 11.

One valve 17 is downstream of the turbocharger 16,
In this case, boost pressure is introduced from one of the downstream merging parts 7 and 8 to the diaphragm 19, and opens only when the boost pressure is below a set value.

The other valve 18 is the injection pump 2
0 via a linkage 22, and is configured to close when the opening degree of the load lever 21 that is linked to the accelerator, that is, the engine load, exceeds a set value.

In this case, the lever 23 formed on the rotation shaft of the valve 18 is inserted into the link 24 of the linkage 22 through the elongated hole 25.
When the load lever 21 reaches a predetermined opening degree, it engages with the end of the elongated hole 25 and is pushed by the link 24 to rotate the valve 18 in the closing direction.

The set boost pressure value that determines the opening timing of the valve 17 is an equal boost pressure value that approximates curve C in FIG. A load value D is taken at which fuel efficiency is worse when only supercharging is performed by a turbo supercharger.

Next, the operation based on such a configuration will be explained.

The valve 17 opens when the boost pressure is below the set value and closes when the boost pressure exceeds the set value. On the other hand, the valve 18 opens when the engine load is below the set value and closes when the load exceeds the set value.

That is, the passage 11 connecting the merging parts 7 and 8 communicates only when the two valves 17 and 18 are open.

Therefore, in the operating region where the passage 11 is blocked (the shaded area in Fig. 3, that is, the region where resonance supercharging is better in addition to turbocharging),
Resonance pipes 9 and 1 are installed in cylinder groups #1 to #3 and #4 to #6 whose intake valve opening timings overlap with each other.
Based on resonance due to zero, resonance supercharging is performed in addition to turbocharging of the turbocharger.

On the other hand, in the movement region where the passage 11 is opened (the area other than the shaded area in FIG. For communication, cylinder group #1~
The intake pulsations of #3 and #4 to #6 interfere with each other, and resonance supercharging is stopped, resulting in supercharging of only the turbo supercharger 16.

Therefore, fuel efficiency can be improved in all operating ranges from low engine speeds and low loads to high engine speeds and high loads.

As described above, according to this invention, in addition to supercharging from the turbo supercharger, resonance supercharging is controlled based on the engine load and boost pressure to ensure the amount of intake air that provides the best combustibility in all operating ranges. As a result, it is possible to achieve the effect of improving fuel efficiency and output.

[Brief explanation of the drawing]

1 and 2 are schematic configuration diagrams of a resonant supercharging device showing the prior art, FIG. 3 is an equal fuel consumption curve diagram based on experimental data, and FIG. 4 is a diagram of a resonant supercharging device showing an embodiment of this invention. It is a schematic block diagram. #1 to #6... Cylinder, 7, 8... Downstream merging section, 9, 10... Resonance tube, 11... Passage, 15...
...Upstream side merging section, 16...Turbo supercharger, 17,
18...Valve.

Claims (1)

[Scope of utility model registration request] A plurality of cylinder groups are provided in which intake passages of cylinders whose intake valve opening timings do not overlap with each other are connected to each other at a downstream merging portion, and a plurality of cylinder groups are each connected to the downstream merging portion of the plurality of cylinder groups. In a diesel engine in which upstream portions of resonance pipes are joined to each other and a turbocharger is provided upstream of the upstream joining portion of the resonance pipe, a passage is formed that connects the plurality of downstream joining portions with each other. In this passage, a valve that opens only when the boost pressure is below the set value based on the boost pressure downstream of the turbocharger, and a valve that opens only when the load is below the set value based on the engine load are installed in series. A resonance supercharging control device for a diesel engine, which is characterized by: