JPH03199624A - Inertia supercharging device for diesel engine - Google Patents

Abstract

PURPOSE:To enlarge the matching range of inertia supercharging by connecting an air cleaner and the innermost ends of intake air ports with both auxiliary resonance passages and auxiliary manifolds so as to add simple pipelines. CONSTITUTION:In a Diesel engine 1 in which inertia supercharging is carried out by providing the intake air system with resonance passages 5 for utilizing the air vibration caused in the resonance passages 5, auxiliary resonance passages 8a, 8b corresponding to the cylinder groups whose suction strokes are not coincident are extendedly provided from an air clearner 4. And by providing auxiliary manifolds 3a, 3b corresponding to the respective cylinder groups, the ends of the auxiliary resonance passages 8a, 8b are opened to the innermost ends of respective intake air ports. In this case, the effective length of the auxiliary resonance passages 8a, 8b is made longer than that of the resonance passages 5, and the sectional area of the pipe for the former is made less than that for the latter. Thus, when the engine 1 is operated in a low-speed range, by the resonance effect of the auxiliary resonance passages 8a, 8b, inertia supercharging of a high efficiency can be enabled.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an intake system for a diesel engine, and more specifically, to an intake system for a diesel engine that can obtain good intake volumetric efficiency over the entire operating range of the engine. This invention relates to an inertial supercharging device for a diesel engine.

<Conventional technology> In order to improve the intake volumetric efficiency of diesel engines,
Inertial supercharging devices that do not consume energy are often provided. By the way, when such an inertial supercharging device is provided, the supercharging characteristics are determined by the resonance frequency of the resonance passage provided in the intake passage, so conventionally two resonance passages with different resonance frequencies have been provided. These resonant passages are selectively used depending on the operating condition of the engine, or the length of the resonant passage is changed to change the resonant frequency, thereby substantially increasing the matching area of the inertial supercharging effect. (Refer to JP-A-59-126028, etc.).

<Problems to be Solved by the Invention> However, even when two resonance passages are used or the length of the resonance passage is changed as in the past, the volume of intake air remains the same throughout the entire operating range of the engine. Improving efficiency has been difficult.

The present invention has been made in view of these circumstances,
The aim is to dramatically expand the matching range of inertial supercharging by adding a simple conduit.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a resonant passage in the intake system so that inertial supercharging is performed using air vibrations generated in the resonant passage. In a diesel engine, the cylinders of the engine are divided into cylinder groups consisting only of cylinders whose intake strokes do not overlap, and the gathering part of the intake manifold and the air cleaner provided corresponding to each cylinder group are connected to resonance passages. are connected via. Further, a communication passage is provided that communicates between the two resonance passages, and a normally closed on-off valve is provided that opens the communication passage only when the engine is operating in a high speed range.

On the other hand, by extending an auxiliary resonance passage corresponding to each cylinder group from the air cleaner and providing an auxiliary manifold corresponding to each cylinder group, the tip of the auxiliary resonance passage can be connected to the innermost end of each intake port. Each of them is opened. The effective length of the auxiliary resonance passage is made longer than the maximum effective length of the resonance passage, and at the same time, the cross-sectional area of the auxiliary resonance passage is made smaller than the cross-sectional area of the 03 passage, thereby inertial supercharging of the diesel engine. configuring the device.

<Operation> In the inertial supercharging device for a diesel engine having such a configuration, when the on-off valve provided in the communication passage that communicates the middle of the resonance passage with each other opens, the effective length of this O1 passage becomes shorter. , when the on-off valve is closed, its effective length increases. Furthermore, as the effective length of the passage becomes shorter or the cross-sectional area of the tube becomes larger, the resonant frequency of the resonant passage becomes higher. Therefore, when the on-off valve provided in the communication passage is opened, the resonant frequency of the resonant passage increases, and when the on-off valve is closed, the resonant frequency is lowered. By opening the on-off valve to increase the resonant frequency, and closing the on-off valve to lower the resonant frequency when the engine is operating in the medium speed range.
This means that sufficient inertial supercharging can be performed in both medium and high speed ranges.

On the other hand, the auxiliary resonance passage is the same as D! Since it is longer than the maximum effective length of the four passages and the cross-sectional area of this auxiliary resonant passage is smaller than that of the resonant passage, the resonant frequency of this auxiliary resonant passage is the lowest resonant frequency of the resonant passage. will be lower than Therefore, when the engine is operated in a low speed (very low speed) region, the auxiliary resonance passage resonates, and the air pushed by this resonance effect is guided from the auxiliary manifold to the inner depths of each intake port. In addition, highly efficient inertial supercharging can be performed even in the low-speed range, which could not be achieved using only the resonance passage, and the overall matching range is dramatically expanded. Also, the air introduced into the intake port via the intake manifold and the air introduced deep into the intake port via the auxiliary manifold flow into the combustion chamber while attracting each other without interfering with each other within the intake port. Therefore, highly efficient supercharging can be performed in the same way as if an air jet were installed.

<Example> Examples of the present invention will be described in detail below based on the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of an inertial supercharging device for a diesel engine according to the present invention, and the fuel injection order is shown in the first cylinder, the fourth cylinder, the second cylinder, the sixth cylinder, and the third cylinder. The intake strokes of the cylinders of an inline 6-cylinder engine 1 set to the cylinder, the fifth cylinder, or the first cylinder, the fifth cylinder, the third cylinder, the sixth cylinder, the second cylinder, and the fourth cylinder do not overlap. The cylinder group is divided into a first cylinder group consisting of only the first to third cylinders and a second cylinder group consisting of only the fourth to sixth cylinders, and each cylinder group is provided with an intake manifold 2a, 2b and an auxiliary manifold 3a, 3b, respectively. has been established.

Further, the gathering portion of the intake manifolds 2a, 2b and the air cleaner 4 are connected through resonance passages 5.5, respectively, and an on-off valve 6 is connected between the resonance passages 5.5.
They are connected to each other via a communication path 7 provided with. The on-off valve 6 is a normally closed valve that opens and closes based on the output of a rotation sensor (not shown), and opens only when it is detected that the engine 1 is being operated in a high-speed region. By shortening the effective length of the resonance passages 5, 5, the resonance frequency can be adjusted to this operating region (high speed region).
When the engine 1 is operated in a medium/low speed range, the on-off valve 6 closes the communication passage 7 to increase the effective length of the resonance passage 5.5. This causes the resonance frequency to match the pulsating frequency of the intake air that occurs in this operating region (medium speed region).

Further, the collecting portions of the auxiliary manifolds 3a, 3b and the air cleaner 4 are connected to auxiliary resonance passages 8a, 8, respectively.
By connecting via b, the auxiliary resonance passage 8a,
Air is introduced from 8a through the auxiliary manifolds 3a and 3b to the innermost end of the intake port 9.

Further, the length of each of the auxiliary resonance passages 8a, 8b is made longer than the maximum effective length of the resonance passage 5, and the tube cross-sectional area of the auxiliary resonance passages 8a, 8b is made smaller than the tube cross-sectional area of the resonance passage 5. Accordingly, this auxiliary resonance passage 8a,
The resonance frequency of 8b is made to match the pulsation frequency of intake air generated in the low speed region of the engine 1.

Therefore, when the engine 1 is operated in the high speed range, the on-off valve 6 opens the communication passage 7 to match the resonance frequency of the resonance passage 5 with the pulsating frequency of the intake air in the high speed range, and the engine 1 is operated in the medium speed range. When this happens, the on-off valve 6 closes the communication passage 7 to make the resonant frequency of the resonance passage 5 coincide with the pulsating frequency of the intake air in the medium speed region of the engine l.

Further, when the engine 1 is operated in a low speed region, the pulsation frequency of the intake air becomes lower than the resonance frequency of the resonance passage 5, so that inertial supercharging by the resonance passage 5 is not performed. However, in this case, the frequency of the intake pulsation of the engine 1 is the same as that of the auxiliary resonance passage 8a.

8b, this auxiliary resonance passage 8
Inertial supercharging is performed by a and 8b.

In other words, in the middle and high speed range of the engine 1, inertia supercharging is performed by the resonance passage 55, and in the low speed range, the auxiliary resonance passage 8
Since inertial supercharging is performed by the motors a and 8b, the volumetric efficiency of intake air is high in all high speed, medium speed and low speed ranges, as shown in FIG.

That is, in the past, two types of resonance passages were provided and one of them was used depending on the operating condition of the engine, or the length of the resonance passage was changed depending on the operating condition of the engine to change the resonance frequency. However, in the present invention, a large amount of air can be introduced in the middle and high speed range of the engine due to the inertial effect of the resonance passage, and in the low speed area of the engine, a large amount of air can be introduced due to the inertial effect of the auxiliary resonance passage. The matching range of inertial supercharging is dramatically expanded.

In addition, since the auxiliary resonance passage, which exerts an inertial effect in the low speed range, is opened at the inner end of the intake port, the air introduced from the resonance passage to the intake port via the intake manifold and the auxiliary resonance passage to the auxiliary manifold are The air introduced into the deep part of the intake port through the old air flows into the combustion chamber while attracting each other without interfering with each other within the intake port. Therefore, highly efficient supercharging can be performed as if an air jet were provided. Furthermore, the auxiliary resonance passage, which exerts an inertial effect in the low speed range, has a small cross-sectional area and a long length, making it easy to run piping from the air cleaner to the auxiliary manifold. It is also possible to suppress the increase in cost due to the addition of this auxiliary resonance passage.

<Effects of the Invention> As is clear from the above description, according to the present invention, the matching range of inertial supercharging can be dramatically expanded by simply adding a simple pipe line to a conventional inertial supercharging device. . Also, simple conduit (auxiliary resonance passage and auxiliary manifold)
Since the desired purpose can be achieved simply by adding , it is also possible to suppress increases in costs.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an inertial supercharging device for a diesel engine according to the present invention, FIG. It is a relationship diagram with volumetric efficiency.

Claims (1)

[Claims] (1) In a diesel engine in which a resonant passage is provided in the intake system and inertial supercharging is performed using air vibrations generated in the resonant passage, a cylinder group is made up of only cylinders whose intake strokes do not overlap. When the engine is operated in a high speed range, there is an intake manifold provided correspondingly to the engine, resonance passages that connect the collective part of each intake manifold and the air cleaner, and a communication passage that communicates the middle of these resonance passages with each other. a normally-closed on-off valve that opens the communicating passage only when the cylinder is in use, an auxiliary resonance passage extending from the air cleaner corresponding to the cylinder group, and an end of each auxiliary resonance passage opening at the innermost end of each intake port. an auxiliary manifold provided in correspondence with each cylinder group in order to make the effective length of the auxiliary resonance passage longer than the maximum effective length of the resonance passage; An inertial supercharging device for a diesel engine characterized by having a cross-sectional area smaller than that of a resonance passage.