JPH03271562A - Intake air passage of internal combustion engine - Google Patents

Abstract

PURPOSE:To correspond to a higher output of an internal combustion engine on condition that compactness of a throttle body is contrived by setting a subflow path part, which constitutes a hot wire current meter subflow path flow-divided from a main flow path to provide a right angle with an air intake direction, and a throttle valve shaft to an equal direction. CONSTITUTION:Air, sucked to an internal combustion engine, passes through a straightening lattice 1 of a main intake air passage and further flow-divides into a main flow path 2 and a subflow path 3, and here is output a flow amount by a hot wire current meter 4 as voltage. Air, flow-divided into the subflow path 3, joins with the main flow path 2 via a subflow path part 3b at a right angle with an air intake direction, and the confluent air is controlled by a throttle valve 8 firmly held to a throttle valve shaft 7. Here the throttle valve shaft 7 is arranged in a direction in parallel t the subflow path 3b and placed perfectly in a shadow of the subflow path 3b when it is projected from the upstream of a bore. That is, more output is gained by reducing a pressure loss and compactness of a body 9 are contrived by enlarging a projection bore area, which is a definite factor of an engine output in the same bore.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the intake passage of an internal combustion engine, and particularly to the intake passage of an internal combustion engine, which has a structure suitable for measuring air flow rate with high accuracy using a hot wire anemometer. Regarding the passage.

[Conventional technology]

A cross-sectional view, an upper view, and a lower view thereof of an intake passage of a conventional internal combustion engine are shown in FIGS. 4, 5, and 6, respectively. 4 to 6, the intake passage of the conventional internal combustion engine includes a body 9, a rectifier grid 1, a hot wire 5 and a cold wire 6 for detecting flow velocity, in a sub-flow passage 3 separated from the main flow passage 2. a hot-wire current meter 4 attached to the engine, a throttle valve 8 fixed to the throttle valve shaft 7 for controlling the intake flow rate to the internal combustion engine, and a sub-flow path A3a in the intake direction forming the sub-flow path 3; The intake passage of the internal combustion engine is composed of a sub-flow passage B3b perpendicular to the intake direction, and is configured to be perpendicular to the direction of the throttle valve shaft 7 and the direction of the sub-flow passage Bab section perpendicular to the intake direction. In addition, an auxiliary air passage (not shown) is provided to bypass the blow-by gas recirculation part and the throttle valve 8, and in recent years, the throttle valve 8
There is a need to have multiple auxiliary air passages to bypass the air, but these are for compensating for electrical loads such as air conditioners and lights, and for acceleration/deceleration, and there is a tendency to set the flow rate of one auxiliary air passage small. It's for a reason. Regarding the intake passage of the conventional internal combustion engine as described above, there is one described, for example, in Japanese Patent Application Laid-Open No. 162413/1983, etc., which reduces the influence of the opening degree of the throttle valve on the output of the hot wire flow meter 4. Therefore, the body has been made larger to increase the distance between the outlet of the sub flow path 3a and the throttle valve 8.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not give sufficient consideration to the effects of the throttle valve opening on the output characteristics of the internal combustion engine and the output characteristics of the hot-wire anemometer. Since the sub-flow path B was perpendicular to the outlet of the sub-flow path B and was provided above the opening/closing part of the throttle valve 8, that is, in the area where pressure fluctuations are large, the outlet part of the sub-flow path B (joint part to the main flow path) was provided. The influence of the throttle valve opening on the output characteristics of the meter has not yet been fully resolved, and efforts have been made to increase the size of the body, resulting in larger throttle bodies and problems with the output accuracy and stability of hot-wire flowmeters. There was a question of sufficiency.

In addition, because the conventional sub-flow path B and the throttle valve shaft 7 were perpendicular to each other, the outlet of the sub-flow path was directly subjected to pressure fluctuations due to backflow, etc., and carbon, etc. in the backflow was transferred to the hot wire 5. There is also the problem that the hot wire anemometer increases changes over time due to blow-by gas contamination due to adhesion to the cold wire 6.

The purpose of the present invention is to make the throttle body more compact and to be able to cope with the higher output of internal combustion engines, and to minimize the influence of the throttle valve opening on the output characteristics of the hot-wire anemometer and the aging change of the anemometer due to blow-by gas. The purpose of the present invention is to provide an intake passage for an internal combustion engine that can be controlled to JX limits.

[Means to solve the problem]

In order to achieve the above object, the intake passage of the internal combustion engine of the present invention has the same throttle valve shaft as the sub-flow passage B, which is perpendicular to the intake direction and constitutes the sub-flow passage for the hot-wire anemometer, which is separated from the main flow passage. The throttle valve shaft is arranged in the shape of the sub flow path B when projected from the upstream side, and the blow-by gas recirculation section bypasses the main passage from upstream to downstream of the throttle valve. The blow-by gas recirculation section and the auxiliary air passage inlet are provided downstream of the auxiliary air passage inlet, and are arranged on the opposite side of the bore away from the auxiliary air passage outlet.

[For production]

The intake passage of the above-mentioned internal combustion engine has the same projected area by arranging the throttle valve shaft in the shape of the sub-flow passage B perpendicular to the intake direction, which constitutes the sub-flow passage in which the sensor part of the hot-wire anemometer is arranged. The bore diameter required to ensure this can be made smaller than when the sub flow path B and the throttle valve shaft are perpendicular to each other, resulting in a structure that allows for a more compact body and higher engine output. In addition, by providing the outlet section of the sub-channel B above the throttle valve axis, the outlet section of the sub-channel B is located at the part of the circumference where the pressure fluctuation is the smallest, so it is possible to determine the opening degree of the throttle valve. By specifying the locations of the blow-by gas recirculation section and the auxiliary air passage inlet as described above, the blow-by Output accuracy and stability are improved by reducing changes over time in the hot wire anemometer due to gas contamination.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a sectional view of an intake passage of an internal combustion engine according to the present invention. 2 is an upper view of FIG. 1, and FIG. 3 is a lower view of FIG. 1. 1 to 3, the intake passage of this internal combustion engine is shown in the body 9 forming the intake passage of the internal combustion engine.
, a rectifying grid l attached to the intake passage inlet of the body 9, and a hot wire 5 and a cold wire 6 of a sensor section for detecting the flow velocity in the body 9, which are connected to the main flow passage 2 in the intake passage.
A hot-wire flow meter 4 is installed to be located in a sub-flow path 3 provided separately from the flow path, a butterfly-type throttle valve 8 that controls the intake air flow rate to the internal combustion engine, and the throttle valve 8 is connected to the body. 9; a sub-flow passage A3a in the intake direction forming the sub-flow passage 3; and a sub-flow passage B3b perpendicular to the intake direction forming the sub-flow passage 3. In the intake passage, the direction of the throttle valve shaft 7 and the direction of the sub-flow passage B3b, which is perpendicular to the intake direction and constitutes the sub-flow passage 3, are arranged in the same direction.

With the above configuration, the air taken into the internal combustion engine passes through an air cleaner (not shown), passes through the rectifying grid 1 of the main intake passage, and is further divided into the main passage 2 and the sub-flow passage 3, where it is connected to a hot-wire anemometer. 4 outputs the flow rate as a voltage, but in detail, the resistance value changes as the temperature of the wire changes due to heat transfer when air flows through the sensor part of the hot wire 5 and cold wire 6. A dependent voltage signal is output from a circuit section (not shown), and the air branched into this sub-flow path 3 flows through the sub-flow path ASa parallel to the intake direction.
After passing through the sensor part of the hot wire 5 and cold wire 6 arranged in the sub-flow path B3b perpendicular to the intake direction
The air flows into the main flow path 2 through the main flow path 2, and after being controlled by a throttle valve 8 fixed to a throttle valve shaft 7, it is supplied to an internal combustion engine (not shown).

The sub-flow path 3 portion in which the sensor portions of the pot wire 5 and the cold wire 6 of the hot-wire current meter 4 are arranged is, for example, a portion of the sub-flow path A3b having a cross section of diameter 10III11 parallel to the main flow air intake direction. and a rectangular groove auxiliary flow path B3b, which is perpendicular to the main flow air intake direction and has a rectangular cross section with a width of 9 mm and a height of 11 cm, and is formed by fixing a plate material from the downstream side with two screws. It consists of.

In the air passage of the internal combustion engine, the driver depresses an accelerator (not shown) to generate an internal combustion engine output (not shown), which changes the opening degree of the throttle valve 8 fixed to the throttle valve shaft 7 via an accelerator cable (not shown) and a lever (not shown). According to the present invention, the single throttle valve shaft 7 is arranged in a direction parallel to the bridge-shaped sub-channel B3b, and is completely in the shadow of the sub-channel B3b when projected from upstream of the bore. That is, it is possible to increase the projected bore area, which is a determining factor in the output of the internal combustion engine, with the same bore diameter, and the pressure loss in the body 9 can be reduced, thereby increasing the output and making the body 9 more compact.

On the other hand, regarding the influence of the opening degree of the throttle valve 8 on the output characteristics of the hot-wire current meter 4, according to the present invention, the outlet section of the sub-channel B3b (merging section with the main channel) is provided above the throttle valve shaft 7 section. The pressure fluctuation above the throttle valve shaft 7 due to the opening of the throttle valve 8 is extremely small compared to the upper part of the opening/closing part of the throttle valve 8, so the pressure fluctuation at the outlet of the sub flow path 3b is small and the opening of the throttle valve 8 is reduced. The output characteristics of the hot wire current meter 4 are stabilized by keeping the division ratio between the main flow path 2 and the sub flow path 3 of the main intake passage constant regardless of changes in the current flow rate. When viewed from the downstream side, the main air passage has a structure in which the throttle valve shaft 7 covers the mouth of the sub-flow passage 3b, which is resistant to blowback from internal combustion engines such as packfires. This structure is advantageous in terms of output accuracy and aging resistance of the hot wire current meter 4.

Next, regarding the arrangement of the blow-by gas recirculation section (not shown), the intake flow direction and the circumferential direction are specified according to the present invention.
It is downstream of the outlet b and downstream of the inlet of an auxiliary air passage (not shown) that bypasses the main passage from upstream to downstream of the throttle valve 8. The reason for this is to prevent blow-by gas from entering the auxiliary air passage and causing problems such as sticking of the seat, and because this blow-by gas contains components such as gum, carbon, and oil, the flow rate is low. In order to prevent this, a blow-by gas recirculation section is provided downstream of the auxiliary air passage where the pressure is lower than the entrance of the auxiliary air passage.

Further, in the circumferential direction, it is provided on the opposite side as far away as possible so as not to affect the outlet part of the sub-flow path B3b, thereby avoiding blow-by gas from entering into the sub-flow path 3. .

In addition, in response to the need to provide a plurality of auxiliary air passages (not shown) that bypass the throttle valve 8, the present invention specifies that these plurality of auxiliary air passages are all directed upward (toward the sky) when mounted on the vehicle.

The reason for this is that atmospheric temperature and humidity or various operating conditions of the internal combustion engine can cause phenomena such as moisture generation or freezing, which can impair the function of the auxiliary air passage. Even if this occurs, the air is allowed to escape from the auxiliary air passage by gravity.

〔Effect of the invention〕

According to the present invention, by providing the throttle valve shaft of the air passage of the internal combustion engine in the shape of the sub-flow passage bridge part (sub-flow passage B part) for the hot-wire anemometer, the body is compact and the pressure loss is small. This makes it possible to cope with the rise in altitude of the internal combustion engine, and the output characteristics of the hot-wire current meter are not affected by the opening degree of the throttle valve. Furthermore, by moving the blow-by gas recirculation part and the auxiliary air passage inlet part away from the outlet part of the sub-flow passage B of the hot-wire anemometer site, the accuracy and stability of the output characteristics of the hot-wire anemometer can be improved and stabilized. Further, by providing the blow-by gas recirculation section downstream of the auxiliary air inlet section and arranging the auxiliary air passage toward the top while mounted on the vehicle, there are effects such as the ability to maintain the normal function of the auxiliary air passage.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the intake passage of an internal combustion engine according to the present invention, FIG. 2 is an upper view of FIG. 1, FIG. 3 is a lower view of FIG. A sectional view showing an example of an intake passage of an engine, FIG. 5 is an upper view of FIG. 4, and FIG. 6 is a lower view of FIG. 4. 1... rectifier grid, 2... main flow path,
3...Subchannel, 3a...Subchannel A, 3b...Subchannel B, 4...Hot wire current meter, 5...Hot wire, 6...Cold wire, 7 ... Throttle valve shaft, 8...
Throttle valve, 9...body. Happy 4

Claims (1)

[Claims] 1. A body forming an intake passage of an internal combustion engine and a sensor unit for detecting the flow velocity in the body are located in a sub-flow passage that branches off a main passage provided in the intake passage. An attached hot-wire flow meter, a butterfly-type throttle valve that controls the intake air flow rate to the internal combustion engine, a throttle valve shaft that holds the throttle valve, and a sub-flow path A in the intake direction that constitutes the above-mentioned sub-flow path. and a sub-flow passage B perpendicular to the intake direction, such that the direction of the throttle valve shaft and the direction of the sub-flow passage B perpendicular to the intake direction constituting the sub-flow passage are the same. An intake passage for an internal combustion engine, characterized by comprising: 2. The intake passage for an internal combustion engine according to claim 1, wherein the auxiliary flow passages B, which are perpendicular to the intake direction and constitute the auxiliary flow passages, are connected in a bridge-like manner in the diametrical direction of the intake passage. 3. The intake passage has a blow-by gas recirculation passage and an auxiliary air passage that bypasses the main passage from upstream to downstream of the throttle valve, and the blow-by gas reflux section is provided downstream of the auxiliary air passage entrance. Claim 1 characterized in that
The intake passage of the internal combustion engine described. 4. The intake passage for an internal combustion engine according to claim 3, wherein the blow-by gas recirculation part and the auxiliary air passage inlet part are provided on the opposite side of the bore away from the auxiliary flow passage outlet part. 5. The air passage for an internal combustion engine according to claim 3, wherein the blow-by gas recirculation passage and the auxiliary air passage are provided upwardly when the engine is mounted. 6. The air passage for an internal combustion engine according to claim 5, characterized in that it has two or more of the auxiliary air passages.