JPS5924822Y2 - Internal combustion engine intake system - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an intake system for an internal combustion engine, and more particularly to an intake system that improves engine performance in response to engine operating conditions.

BACKGROUND ART An inertial supercharging type intake passage is well known as a means for improving the intake air filling efficiency of an internal combustion engine.

This inertial supercharging type intake passage actively utilizes pressure vibrations of intake air based on negative pressure waves generated near the intake port at the start of the engine's intake stroke to force air into the cylinder. For this reason, the matching area for inertial supercharging must be specified by appropriately selecting the dimensions and shape of the intake passage.

In addition, in a multi-cylinder engine, each cylinder group consisting only of cylinders whose intake strokes do not overlap (cylinders whose intake valve opening timings do not overlap) has a size and shape that has the natural frequency of the air column that matches the intake pressure vibration. It is necessary to provide intake passages in parallel.

By the way, in the case of such an inertia supercharging type intake passage, the intake air filling efficiency can be improved in the rotational speed range where inertia supercharging is performed compared to a normal type intake passage that does not use inertia supercharging, but on the other hand, the passage length Pumping loss increases as .

In this case, when the engine is operated under high load, the effect of improving intake air filling efficiency due to inertial supercharging outweighs the negative side of pumping loss, resulting in high output and low fuel consumption, reduced smoke, reduced exhaust temperature, and further lowers the maximum rotation speed. This has greater effects than a normal intake passage, such as reducing noise.

However, when the engine is under medium or low load, the negative side of increased pumping loss becomes greater than the effect of improving intake air filling efficiency through inertial supercharging, resulting in a decrease in output, an accompanying increase in fuel consumption, an increase in NOx, and an increase in noise. etc. The performance was lower than that of a normal type intake passage.

The present invention was devised in view of the conventional situation, and includes a plurality of non-throttled passages connected to a plurality of cylinders whose intake valve opening timings overlap with each other, which are arranged in parallel with each other. A passage switching means is provided which allows the upstream parts of the passages to merge and communicate with each other, while the downstream parts are linked to a control lever of a fuel injection pump to freely interrupt communication;
The downstream parts of multiple passages are cut off from each other at high load positions of the control lever, and an inertia supercharging type intake passage is selected.
An object of the present invention is to provide an intake system for an internal combustion engine, which is configured so that a normal intake passage is selected in communication at a low load position, and is capable of improving operating performance in all operating ranges.

The present invention will be described below based on illustrated embodiments.

The figure shows an example in which the present invention is applied to a 6-cylinder engine, and the ignition order for every 120° crank angle of cylinders #1 to #6 in the engine is 1 → 4P4 → Φ2 → Φ6 → Φ3 → -4P.
5, therefore cylinder 4#1. +-2 and Φ3 (
(hereinafter referred to as the first cylinder group 1), the intake valve opening timings of each cylinder do not substantially overlap, and cylinders +4. Φ5 and +6
(hereinafter referred to as the second cylinder group 2), the intake valve opening timings of each cylinder do not substantially overlap, but the first cylinder group 1 and the second cylinder group 2 have a relationship in which the intake valve opening timings overlap with each other. .

The downstream end of each branch part of the intake manifold 3 is connected to the intake port of each cylinder #1 to +6 of the engine, and the resonant intake pipe 4 is connected to the upstream end of the manifold 3.

The upstream end of the resonance type intake pipe 4 is connected to an air cleaner 2 (not shown).
Connect to the next side or the blower outlet of the turbocharger.

Here, a partition wall 5 is provided inside the resonance type intake pipe 4 to partition it into two parallel passages 6 and 7, and at the gathering part of the intake manifold 3 on the downstream side of the partition wall 5, a pipe is connected to the first cylinder group 1. Space 3A in the communicating intake manifold 3 and the second cylinder group 2
A passage switching valve 8 is interposed between the downstream end of the partition wall 5 and the space 3B that communicates with the partition wall 5 as a passage switching means that can freely communicate or block the communication with the downstream end of the partition wall 5.

The passage switching valve 8 is connected to a control lever 10 of a fuel injection pump 9 via a wire 11, and at a high load position corresponding to a fuel injection amount position of a predetermined value or more of the control lever 10, the switching valve 8 is connected to a control lever 10 of a fuel injection pump 9. The switching valve 8 is set so as to cut off the spaces 3A and 3B from each other, and allow the spaces 3A and 3B to communicate with each other at middle and low positions corresponding to positions where the fuel injection amount is less than the predetermined value.

Therefore, when the switching valve 8 is in the cutoff position, the intake passage connected to the first cylinder group 1 that does not have a throttle part and the intake passage that also does not have a throttle part that is connected to the second cylinder group 2 are separated by a partition wall. The size and shape of the intake passage portion which connects and connects on the upstream side of the 5 and reaches the cylinders Φ1 to -Ip3 through the passage 6 and the space 3A on the downstream side of the merging point, and the cylinders Φ4 to Φ6 through the passage 7 and the space 3B. The dimensions and shape of the intake passage leading to the engine are designed to be compatible with inertial supercharging in the normal rotation range.

12 is an exhaust manifold. Next, the operation of this intake device will be explained.

During high-load operation of the engine, the switching valve 8 isolates the spaces 3A and 3B from each other in response to the position of the control lever 10. By selecting an inertial supercharging type intake passage that joins and communicates with the connected intake passage on the upstream side of the partition wall 5, inertia supercharging that matches the normal rotational speed range is performed by each of these intake passages.

As a result, during high-load operation, the inertia supercharging function that overcomes pumping loss can increase output and reduce fuel consumption, as well as reduce smoke and exhaust temperature.
Furthermore, since the maximum rotation speed can be reduced, noise can be reduced.

On the other hand, during medium/low load operation, the switching valve 8 is
Since B is switched to the position where they communicate with each other, the natural frequency of the air column, which is determined by the dimensions and shape of the intake passage from the approximate volume cylinder to the gathering part of the intake manifold 3, increases significantly, and inertial supercharging occurs in the normal rotation speed range. It is outside the matching area and becomes a normal intake passage that does not utilize inertial supercharging.

Therefore, by selecting the normal type intake passage during such medium/low load operation, it is possible to suppress the increase in pumping loss due to inertial supercharging, and as a result, higher output can be obtained compared to the inertial supercharging type passage, reducing fuel consumption. This makes it possible to reduce NOx and noise.

In addition, the passage switching valve is not directly linked to the control lever of the fuel injection pump, but is turned on and off via an electromagnetic actuator or air cylinder based on the load value detected by the control lever position.
They may also be linked so that they open and close at will.

Further, by providing the partition wall 5, the inertial supercharging type intake passage and the normal type intake passage can be formed in a common intake passage, making it more compact.However, by forming these two types of intake passages separately, it is possible to It goes without saying that the present invention also includes a switchable switch.

As explained above, according to the present invention, the inertial supercharging intake passage is used during high-load operation of the engine, and the regular intake passage is used during medium- and low-load operation, so that It is possible to improve engine performance, and in particular, it is possible to improve output, reduce fuel consumption, reduce polluting exhaust substances such as smoke and NOx, and reduce engine noise over the entire operating range.

BRIEF DESCRIPTION OF THE DRAWINGS The figure is a schematic diagram showing an embodiment of the present invention. 3...Intake manifold, 3A, 3B...
・Space, 4... Resonance type intake pipe, 5...
Bulkhead, 6, 7... Passage, 8... Passage switching valve, 10... Control lever, 11...
...Wire.

Claims (1)

[Scope of utility model registration request] A plurality of passages without a throttle part are arranged in parallel to each other and are connected to a plurality of cylinders whose intake valve opening timings overlap with each other, and the upstream parts of these passages are brought into confluence and communication with each other, while the downstream part A passage switching means is provided which can freely communicate with and cut off communication with each other, and the passage switching means is linked to a control lever of the fuel injection pump, and the downstream portions of the plurality of passages are cut off from each other at a high load position of the control lever. Select an inertia supercharging type intake passage whose size and shape are compatible with inertia supercharging in the normal rotation speed range of An intake system for an internal combustion engine, characterized in that it has a selective configuration.