JPH0121135Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention relates to a diesel engine supercharging control device.

(Prior Art) Some diesel engines employ resonance supercharging in order to increase the intake air filling efficiency of 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. 5, for example (Japanese Utility Model Publication 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.

Then, a passage 11 is formed that communicates the merging parts 7 and 8, and this passage 11 is closed in a high engine load region.
A valve 12 that opens in a low load range is installed.

Note that 13 indicates a load lever of an injection pump 14, and the load lever 13 opens and closes the valve 12 via a wire 15 in accordance with the opening degree of the accelerator.

Therefore, in the engine high load range, valve 12
is fully closed and blocks the passage 11 of 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 cylinder groups #1 to #3 and #4 to #6 interfere with each other, and as a result, a resonance phenomenon is no longer obtained, and resonance supercharging is stopped.

In other words, resonance supercharging is stopped in a low engine load range with a small amount of fuel injection to avoid an increase in pumping loss due to excessive intake.

(Problem to be solved by the invention) By the way, when the above-mentioned resonance supercharging device is adopted in a diesel engine with a turbo supercharger, it is difficult to improve the negative effects (deterioration of fuel efficiency, smoke, etc.) associated with resonance supercharging. It has been experimentally confirmed that, for example, if turbocharging and resonance supercharging are controlled as shown in FIG. 4, good operating performance can be obtained over the entire operating range.

In the figure, A and B are regions where both turbocharging and resonance supercharging are performed, T is a region where only turbocharging is performed, and N
stops turbocharging and resonant charging (i.e.
Indicates the region (to achieve naturally aspirated state).

Therefore, this idea was developed based on the above control characteristics to control turbo supercharging and resonance supercharging for diesel engines to achieve good driving performance (improvement in fuel economy, smoke, etc.) in all operating ranges. The purpose is to provide a supply control device.

(Means for Solving the Problem) Therefore, this invention aims to provide a diesel engine with a turbocharger in which resonance pipes are connected to the cylinders whose intake valve opening timings do not overlap each other through a merging section. and a bypass passage that communicates this passage with the intake passage upstream of the turbocharger, and these passages are opened and closed at the junction of the passage with the bypass passage depending on the engine operating state. Install a rotary valve.

(Function) Therefore, the rotary valve can open and close the bypass passage and the communication passage depending on the engine operating condition to switch to a naturally aspirated region, a turbo supercharging region, and a combination of turbo supercharging and resonance supercharging. As a result, good driving performance can be obtained over the entire driving range.

(Example) In FIG. 1, 9 and 10 indicate resonance pipes, and the resonance pipes 9 and 10 are connected to cylinders #1 to #1 through which the opening timings of the intake valves do not overlap through confluence portions 7 and 8, respectively.
Connect to #3 and #4 to #6.

Note that the resonance pipes 9 and 10 merge on the upstream side, and a turbo supercharger 17 is installed upstream of the merged portion 16.

The turbo supercharger 17 supercharges the cylinders #1 to #3 and #4 to #6 from the resonance pipes 9 and 10 via the confluence section 16 in accordance with the engine speed.

The merging portions 7 and 8 on the downstream side of the resonance pipes 9 and 10 are communicated through a passage 11, and a bypass passage 18 branched from upstream of the turbocharger 17 joins the passage 11.

A rotary valve 20 is interposed at the confluence of the passages 11.

As shown in FIG. 2, the rotary valve 20 is
Three valve plates 22 are arranged radially around a rotating shaft 21 at predetermined intervals, and are rotatably supported inside a cylindrical valve housing 23 via the rotating shaft 21.

The rotary valve 20 is in the first valve position shown by the solid line in the figure, and the merging portions 7 and 8 of the valve housing 23
The openings 24 and 25 on the side and the opening 26 on the side of the bypass passage 18 are all communicated, and the openings 24 to 26 are all blocked at the second valve position shown by the dashed-dotted line, while the bypass is opened at the valve position shown by the dashed-dotted line. The opening 26 on the passage 18 side is blocked, and the openings 24 and 25 on the merging portions 7 and 8 are communicated with each other.

The rotary shaft 21 of the rotary valve 20 is connected to a piston rod 29 of an air cylinder 28 through a lever 27 outside the valve housing 23, as shown in FIG. The valve position is switched to three stages as described above.

The air cylinder 28 has two pistons 30 inside.
and 31 are housed coaxially, and the working chambers 32 and 33 of the first and second pistons 30 and 31 are respectively connected to the first and second solenoid valves 34 and 35 (the working chambers 30 and 31 are set to atmospheric pressure). connected to the air reservoir via the air pressure switch.

The power supply circuit for the first solenoid valve 34 includes a switch 36 that closes when the control lever 13 of the fuel injection pump is opened at a predetermined opening or higher (high load range), and the power supply circuit for the second solenoid valve 35 includes A switch circuit 38 is provided which closes when the engine rotation is within a predetermined rotation speed range (medium rotation range) based on a detection signal from the rotation sensor 37.

The air cylinder 28 is connected to the first piston 3
When air pressure is supplied to the working chamber 32 of 0, the first piston 30 and the second piston 1 extend the piston rod 29 by a predetermined stroke L ₁ (regulated by the partition wall 39), and the lever 27 to move the rotary valve 20 from the first valve position to the second valve position.
When the rotary valve 20 is rotated to the valve position and air pressure is supplied to the working chamber 33 of the second piston 31 in this state, the second piston rod 29 is further extended by a predetermined stroke L ₂ . from the second valve position to the third valve position. 40 indicates a return spring.

Therefore, in the low load range, the rotary valve 20 is in the first valve position and the opening 2 on the bypass passage 18 side is closed.
Since the openings 24 and 25 on the 8 side are all in communication with the merging section 7 and the openings 24 and 25 on the 8 side, intake air is supplied to each cylinder #1 to #6 from upstream of the turbocharger 17 via the bypass passage 18, and resonance supercharging and turbo It becomes a state where supercharging is stopped, that is, a naturally aspirated state.

On the other hand, in a high load range, when the switch 36 is closed, air pressure is applied to the working chamber 32 via the first solenoid valve 34.
The rotary valve 20 is rotated to the second valve position by the expansion of the air cylinder 28 as described above. In this case, since the rotary valve 20 blocks all the openings 24 to 26, turbo supercharging and resonance supercharging are performed.

In addition, when the switch circuit 38 is closed in the high load medium rotation range, the working chamber 33 is opened via the second solenoid valve 35.
Air pressure is supplied to both, which causes the air cylinder 28 to further expand and move the rotary valve 20 to the third position.
Rotate the valve to the valve position.

In this state, the opening 26 on the side of the bypass passage 18 is blocked and the openings 24 and 25 on the merging sections 7 and 8 are communicated with each other, so that resonance supercharging is stopped and supercharging is performed only by the turbo supercharger.

In this way, it is possible to switch to a naturally aspirated state in the low load range, a combination of turbocharging and resonance supercharging in the high load and high speed range, and furthermore, to a turbocharged state in the high load medium speed range. Since substantially the same supercharging characteristics as shown in Fig. 4 can be obtained, good driving performance (improved fuel efficiency and smoke) is ensured over the entire operating range.

Note that if a microcomputer is employed as the control means for the solenoid valves 34 and 35, the control characteristics can be further improved.

(Effects of the invention) In short, according to this invention, it is possible to switch between the naturally aspirated state, turbocharging state, and combination of turbocharging and resonance supercharging depending on the engine operating state, so it can be used in all operating ranges. The effect of improving fuel efficiency and smoke can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of this invention.
Fig. 2 is a sectional view taken along line A-A, Fig. 3 is a rotary valve control circuit, Fig. 4 is an experimentally confirmed supercharging control characteristic diagram, and Fig. 5 is a resonant supercharging device showing the conventional technology. It is a schematic configuration diagram. #1 to #6... Cylinder, 7, 8... Merging section, 9,
10... Resonance tube, 11... Passage, 17... Turbo supercharger, 18... Bypass passage, 20... Rotary valve.

Claims (1)

[Scope of utility model registration request] In a diesel engine equipped with a turbocharger, in which a resonance pipe is connected to each cylinder via a confluence section, the cylinders whose intake valve opening timings do not overlap with each other, a passage connecting the confluence section with each other and a passage connecting this passage to the turbo supercharger are provided. A bypass passage communicating with an upstream intake passage is provided, and a rotary valve for opening and closing these passages in accordance with engine operating conditions is installed at the junction of said passage with the bypass passage. Feeding control device.