JPH0230923A - Air intake device for six cylinder engine - Google Patents

Abstract

PURPOSE:To secure sufficient volumetric efficiency even in a low engine speed area by dividing respective cylinders into some groups as a pair by one group and making the intake distance of the respective group 360 degree in the intake system having variable intake pipe length. CONSTITUTION:The respective cylinders #1-#6 of a six cylinder engine is divided into as a pair by one group and are connected at the respective cylinder passages 2-4 so as to make the intake distance of the cylinders of the respective groups 360 degree. The respective intake passages 2-4 are connected to respective collecting intake passages 2a-4a at positions equal distance to the respective intake ports 5 and then to be connected to an intake chamber 6. A collecting position between the respective intake passages 204 and the respective collecting intake passages 2a-4a are connected at respective passages 10, 11 one another. Further, respective shut-off valves 12, 13 which are opened at only the time of high engine speed are arranged. Accordingly, sufficient volumetric efficiency is secured even in a low engine speed area.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an intake system for a six-cylinder engine installed in an automobile.

[Conventional technology]

As an intake system for this type of 6-cylinder engine,
As described in Publication No. 0-233312, #1.3.5 cylinders and #2.4.6 cylinders are grouped,
The intake passages corresponding to each grouped cylinder are communicated at the long and short positions of the intake passages, and the short positions are used to block the communication points that are controlled to open at high engine speeds. Some are known to have valves installed. For this reason, if the intake interval is made larger than 240 degrees between cylinders in a common group, intake interference will occur. For this reason, the overlap of intake timings in cylinders in the same group is set to zero.

[Problem to be solved by the invention]

However, with such a configuration, it is difficult to obtain sufficient volumetric efficiency in the low engine rotation range. The present invention was made based on the above circumstances, and in an intake system with a variable intake pipe length for a six-cylinder engine, the cylinders are divided into groups of two and the intake interval is set to 360 degrees, thereby reducing at least the engine's performance. The present invention aims to provide an intake system for a six-cylinder engine that can obtain sufficient volumetric efficiency even in the rotation range.

[Means to solve the problem]

Therefore, in the present invention, in a six-cylinder engine, the cylinders are divided into groups of two cylinders so that the intake interval between the cylinders in each group is 360 degrees, and the intake passages of each group are connected through a collective intake passage. A communication passage is provided that communicates with the intake chamber and connects the meeting point of the intake passage and the collective intake passage with each other, and a shutoff valve that is controlled to open when the engine rotates at high speed is installed in the communication passage. .

[For production]

Therefore, with such a configuration, the intake interval can be set to 360 degrees, and sufficient volumetric efficiency can be obtained even in the low rotational speed region of the engine.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In the figure, numeral 1 is a horizontally opposed engine, and each bank has #1. #3. #5 and #2. #
4. Each cylinder #6 is arranged. The above cylinder is #1. #2 is the first group and communicates with the intake passage 2; #3. The #4 cylinders form a second group and communicate through an intake passage 3, and the #5 and #6 cylinders form a third group and communicate through an intake passage 4. The intake passages 2, 3.4 communicate with the collective intake passages 2a, 3a, 4a at positions equidistant from the intake boat 5 of each cylinder, respectively, through the collective intake passages 2a, 3a, 4a. and communicates with the intake chamber 6. The intake chamber 6 is communicated with an air cleaner 9 via a throttle valve 7 and a flexible conduit 8. On the other hand, the collective intake passage 2
The intake passages 2, 3.4 including the intake passages 2, 3.4 including the intake passages 2, 3, and 4a have long intake passage lengths L1L2, L3 up to the intake chamber 6, and the collective intake passage 2a. 3a, 4a and the intake passages 2, 3.4 meet, the short intake passage length JL1. J12. j! A communication passage 10.11 is provided at the position 3 to communicate the intake passages 2, 3.4 with each other. A shutoff valve 12.13 is provided in the communication F#110.11. 'I for controlling the opening and closing of the above-mentioned shutoff valve 12.13
The iJm system uses a diaphragm actuator 14. A three-way switching solenoid valve 15 for selectively supplying negative pressure or atmospheric pressure to the working chamber 14a of the diaphragm actuator 14. A rotation speed switch 16 that energizes the solenoid coil 15a of the three-way switching solenoid valve 15 when the engine rotation speed is below a predetermined value. Negative pressure tank 17 as a source of negative pressure to the three-way switching solenoid valve 15. and communicates with the intake chamber 6 for supplying negative pressure to the negative pressure tank 17, and check valve 1.
8 and a negative pressure passage 19. In addition,
In the figure, numeral 20 is a power source, 15b is a return spring of the three-way switching solenoid valve 15, 15c is a negative pressure side boat communicating with the negative pressure tank 11, and 15d is an atmosphere side boat. In such a configuration, when the engine speed is below a predetermined value, the speed switch 16 is turned on and the solenoid coil 16 is turned on.
Since a is energized and excited, the atmosphere side boat 15d of the three-way switching solenoid valve 15 is closed and the negative pressure side boat 15c is opened, so that the negative pressure in the negative pressure tank 17 reaches the working chamber 14a of the actuator 14. , close the isolation valve 12.13. Therefore, the intake pipe lengths in each cylinder are Ll and L2. L3, and the interference point is inside the intake chamber 6. Moreover, since the intake interval for each group is 360 degrees, intake inertia can be utilized to achieve intake with sufficient volumetric efficiency. Further, when the engine speed is above a predetermined value, the speed switch 16 is turned off, the solenoid coil 15a is deenergized, and the return spring 15b L:
f) By fJI, the negative pressure side boat 15c is closed and the atmosphere side boat 15b is opened, so that the working chamber 14a is communicated with the atmosphere via the three-way switching solenoid valve 15. As a result, when the 'iL cutting pulp 12.13 is opened, intake interference occurs within the communication passage 10.11, and the actual intake pipe length is 11.1. It is shortened to Jt2.13. This lick,
It is possible to increase the volumetric efficiency at high engine speeds. Incidentally, as can be understood from FIG. 5, the relationship between volumetric efficiency and engine speed shows different characteristics when the intake pipe length is long (solid line) and when it is short (dotted line). Therefore, it is preferable to set the engine rotation speed NO at which the volumetric efficiency is reversed to a predetermined value of the rotation speed switch 16. Note that the volumetric efficiency changes not only depending on the engine speed but also on the load condition, so as shown in Fig. 4, the control unit 2
1, the detected value of the throttle sensor 22 is obtained, and the load condition is detected by the throttle opening calculation means 21a.Meanwhile, the detected value of the engine rotation speed sensor 23 is obtained, and the engine rotation speed is calculated by the engine rotation speed calculation means 21b. The table search means 21c performs a table search (see FIG. 6) to control the on/off of the switch means 16' consisting of a transistor, thereby switching the three-way switching solenoid valve 15 to reduce engine speed. The shutoff valve 12.13 may be closed in a low load region, and opened in other regions.

【Effect of the invention】

The present invention has been described in detail above, and in a six-cylinder engine, the cylinders are divided into groups of two with a configuration of variable intake pipe length, and the intake interval is set to 360 degrees, so that the engine can be operated at least in the low rotation range of the engine. Sufficient volumetric efficiency can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a front sectional view of the embodiment showing a control mode for varying the length of the intake pipe, FIG. 3 is a side sectional view of the same, and FIG. 4 is a front sectional view of another embodiment, FIG. 5 is a characteristic diagram showing the relationship between the volumetric efficiency corresponding to the intake pipe length and the engine speed, FIG. 6 is a graph showing the head setting for table search, and FIG. Figure 7(a),
(b) is a schematic configuration diagram showing the actual intake pipe length. 1... Engine, 2, 3.4... Intake passage, 2a,
3a. 4a... Collective intake passage, 5... Intake boat, 6...
・Intake chamber, 7... Throttle valve, 8...
Flexible pipe line, 9... Air cleaner, 10.11... Communication path, 12.13... Shutoff valve. Figure 1 Engine rJk motor ( Figure 6 Engine nnn a rotation% LN

Claims (1)

[Claims] In a six-cylinder engine, the cylinders are divided into groups of two cylinders so that the intake interval between the cylinders in each group is 360 degrees, and the intake passages of each group are communicated with the intake chamber via a collective intake passage,
A six-cylinder engine characterized in that a communication passage is provided to communicate the meeting point of the intake passage and the collective intake passage with each other, and a shutoff valve that is controlled to open at high engine speed is installed in the communication passage. Intake device.