JPH10246113A - Intake device for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the performance in the all regions of an engine by arranging a main intake passage connected to a first air box from one intake valve in a plurality of intake valves arranged per cylinder, an auxiliary intake passage connected to a second air box from the other intake valve, and an intermediate speed passage opened to the second air box branching the main intake passage. SOLUTION: At the time of an intermediate speed operation, an intermediate speed passage 10 is closed by an intermediate speed valve 14, and an auxiliary intake passage 12 is also closed by a high speed valve 13. At the time of an intermediate speed operation, a main intake passage 11 is opened to an air box 16 by opening the intermediate speed valve 14 of the intermediate speed passage 10 branched on the way, and an intake pipe distance between an intake valve 21a and the air box 16 is shortened so as to synchronize with an intermediate speed operation region. Air boxes 15, 16 are communicated with each other through a communicating pipe by opening the intermediate speed valve 14, and fresh air is supplied from the air box 15 to the air box 16. At the time of a high speed operation, the high speed valve 13 and the intermediate speed valve 14 are opened together, the main intake passage 11 is opened to the air box 16 together with the auxiliary intake passage 12 through the intermediate speed passage 10, and thereby, the cross sectional area of the intake pipe is enlarged, and is synchronized to a high speed operating region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a high-performance engine suitable mainly for a passenger car, and more particularly to an installation structure of an intake pipe and an air box attached to an engine body.

[0002]

2. Description of the Related Art In recent years, automobile engines have been pursuing improvement in high-speed performance, but also have a relatively long intake passage so as not to sacrifice low-medium-speed performance even in high-speed engines. Recently, it has been considered to further shorten the intake passage for high speed.

[0003]

However, as described above, in a high-speed engine, it is not possible to improve the performance over the entire use range of the engine by using only the high-speed intake passage and the low-speed intake passage.
A variable intake valve opening / closing timing device is installed to supplement this.

[0004]

According to the present invention, there is provided a high-speed engine as described above, wherein these are rationally arranged to provide a medium-speed intake passage, and a first air passage from one intake valve to the atmosphere is provided. A main intake passage connected to the second air box is provided, a sub-intake passage connected to the second air box from the other intake valve and a high-speed valve that opens when the engine operates at a high speed are provided, and the main intake passage is branched midway to It is characterized in that a medium-speed passage opening to the air box is provided, and a medium-speed valve that opens at the time of medium-speed operation and high-speed operation of the engine is provided in the medium-speed passage.

[0005]

According to the intake device of the present invention, a main intake passage is provided for connecting one of the intake valves to the first air box communicating with the atmosphere, and a sub-intake passage is provided for connecting the other intake valve to the second air box. A high-speed valve that opens during high-speed operation of the engine is provided, and a middle-speed passage that branches off the main intake passage and opens to the second air box is provided. The provision of the opening medium speed valve improves the performance in almost the entire use range of the engine.

Incidentally, in the case of the conventional structure, the intake device is provided with a high-speed intake passage and a low-speed intake passage. However, the performance cannot be improved over the entire use range of the high-speed engine, and a variable intake valve opening / closing timing device and the like are not provided. There was a problem that I had to make up for it or give up improving the performance in some rotation ranges.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIGS. 1 to 5 are views for explaining an intake device of a four-stroke engine according to an embodiment of the present invention.
FIG. 3 is a top view of the intake device. 2, 3, 3, 4 and 5 are a sectional view taken along line AA, a sectional view taken along line BB, a sectional view taken along line CC, and a sectional view taken along line DD of FIG. 1.

In FIG. 1, reference numeral 1 denotes a water-cooled four-stroke in-line four-cylinder engine employing the present embodiment, which has a crank chamber separating wall 9 and an oil pan 4 mounted on a lower surface of a cylinder block 2 and an upper surface on the upper surface. Cylinder head 3
And the intake devices 10 to 18 are fastened.

A total of four cylinders (cylinder bores) are formed in the cylinder block 2 in series in the direction of the crankshaft. A piston 7 inserted in each cylinder is connected to the crankshaft 5 by a connecting rod 6. . The cylinder includes a combustion chamber 8 including a cylinder block 2, a cylinder head 3, a piston 7, a spark plug 26, and a fuel injection valve 19. An ignition coil 27 is connected above the spark plug 26, and the fuel injection valve 19 is sandwiched and fixed between the fuel pipe 20 and the cylinder head 3.

The combustion chamber 8 is connected to intake passages 11 and 12 via an intake valve 21 and an exhaust passage 25 via an exhaust valve 22. The intake valve 21 and the exhaust valve 22 are connected by the crankshaft 5 respectively. It is opened and closed by a driven intake camshaft 23 and an exhaust camshaft 24. Each camshaft is driven by a timing belt or chain wound between crankshafts, not shown.

In the present invention, the combustion chamber is connected to the main air intake passage 11 which takes in air to the entire operation range via one intake valve 21a, and is connected to the first air box 15 which communicates with the atmosphere. Further, it is connected to the auxiliary intake passage 12 through which the intake air is taken during high-speed operation via the other intake valve 21b, and is opened to the second air box 16. The main air intake passage 11 branches off in the middle and the second air box 1
6 is provided with a middle-speed passage 10. A high-speed valve 13 that opens in high-speed operation in the sub intake passage 12, and a medium-speed valve 1 that opens in medium-speed operation and high-speed operation in the medium-speed passage 10.
4 are provided. The first air box 15 is open to the atmosphere via a throttle valve 18 and a collecting pipe (not shown) and an air purifier, and one end communicates with the second air box 16 via a communication pipe 17 and a medium speed valve 14. ing. High speed valve 13 and medium speed valve 14
Are arranged so as not to interfere with the main intake passage 11 and the sub intake passage 12, respectively.

Next, the operation and effect of this embodiment will be described. Main intake passage 11 of engine 1 equipped with the present embodiment device
Is made long with an intake passage sectional area of 40% to 60% of the intake passage sectional area of each cylinder. During low-speed operation, the medium-speed passage 10 that branches off in the middle is closed by a medium-speed valve 14, and the sub-intake passage 12 is also closed by the high-speed valve 13 so that intake is not performed, so that the operation is tuned to a low-speed operation range. Further, the intake valve 21a and the high-speed valve 13
The back pressure of the combustion gas at the time of overlap is reduced due to the fact that the pressure in the passage is not affected by the other cylinders and the volume of the passage is small due to the fact that the opening area of the intake valve 21 at the time of overlap is reduced. As a result, even when the operating angle of the intake camshaft 23 is increased by that amount, idling and combustion in a light load region can be kept good.

During the middle speed operation, the main intake passage 11 is opened to the second air box 16 by opening the middle speed valve 14 of the middle speed passage 10 branched in the middle, and the intake air from the intake valve 21a to the second air box 16 is opened. The pipe length becomes shorter and it tunes to the medium speed operation range. Since the high-speed valve 13 is closed in the sub intake passage 12 as in the low-speed operation,
No inspiration takes place. The first air box 15 and the second air box 16 communicate with each other through the communication pipe 17 when the middle speed valve 14 is opened, and fresh air is supplied from the first air box 15 to the second air box 16.

During high-speed operation, the high-speed valve 13 and the medium-speed valve 14 are both opened, and the main intake passage 11 is opened to the second air box 16 together with the sub-intake passage 12 through the middle-speed passage 10 branched on the way. The cross-sectional area of the pipe increases, and it tunes to the high-speed operation range.
Further, as described above, by increasing the working angle of the intake camshaft 23, the pulsation effect can be more greatly utilized, so that the performance in the high-speed operation range can be further improved.

[0015]

As described above, according to the intake system for an engine according to the present invention, a main intake passage is provided which is connected from one intake valve to a first air box communicating with the atmosphere, and the other intake valve is provided with a second air passage. A sub-intake passage connected to the box and a high-speed valve that opens when the engine is running at a high speed are provided. A medium-speed passage that branches off the main intake passage and opens to the second air box is provided. Providing a medium-speed valve that opens at the time of high-speed operation and high-speed operation and increasing the operating angle of the intake camshaft 23 have the effect of improving the performance over almost the entire range of use of the engine.

[Brief description of the drawings]

FIG. 1 is a top view of an intake device of a four-cycle engine.

FIG. 2 is a sectional view taken along the line II-A of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

FIG. 5 is a sectional view taken along line DD of FIG. 1;

[Explanation of symbols]

1 ... 4 cycle engine 17 ... communication pipe 2 ... cylinder block 18 ... throttle valve 3 ... cylinder head 19 ... fuel injection valve 4 ... oil pan 20 ・..Fuel pipe 5 ... Crankshaft 21 ... Intake valve 6 ... Connect rod 22 ... Exhaust valve 7 ... Piston 23 ... Intake cam shaft 8 ... Combustion chamber 24 ... Exhaust cam shaft 9 ... Crank chamber separation wall 25 ... Exhaust passage 10 ... Medium speed passage 26 ... Spark plug 11 ... Main intake passage 27 ... Ignition coil 12 ...・ Sub intake passage 13 ・ ・ ・ High speed valve 14 ・ ・ ・ Medium speed valve 15 ・ ・ ・ First air box 16 ・ ・ ・ Second air box

Claims (1)

[Claims] 1. An intake system for an engine having a plurality of intake valves, wherein a main intake passage is provided for connecting one intake valve to a first air box communicating with the atmosphere, and the other intake valve is connected to a second air box. The auxiliary intake passage and a high-speed valve that opens during high-speed operation of the engine are provided.A medium-speed passage that branches off the main intake passage and opens to the second air box is provided. Engine intake system with a medium-speed valve that opens during high-speed operation