JPH0639050Y2 - Intake device for multi-cylinder internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an intake system for a multi-cylinder internal combustion engine.

<Prior Art> The following is a conventional example of an intake system for a multi-cylinder internal combustion engine (see Japanese Utility Model Laid-Open No. 61-86533).

That is, this one is equipped with an intake manifold provided with a plurality of branch passages that are independently connected to each cylinder group so that the opening timings of the intake valves do not overlap with each other, and the resonance pipes are attached upstream of each branch passage. ing. Further, a compressor of the turbocharger is attached upstream of the resonance tube.

Then, the intake supercharging efficiency in the high load operation region is increased by the resonance supercharging.

<Problems to be Solved by the Invention> However, in such a conventional intake device,
Resonance supercharging improves intake charge efficiency in high-speed / high-load operation range, but conversely increases pumping loss in low / medium-load operation range to decrease intake charge efficiency, resulting in lower engine output or worse fuel efficiency. There is a problem called. Further, in this structure, it is necessary to provide a heater for intake air heating in each branch passage in order to improve startability, which causes a problem of high cost.

Further, in an internal combustion engine that does not utilize resonance supercharging, as shown by the broken line in FIG. 5, there is a problem that the engine output is reduced and the smoke emission amount is increased because the intake flow rate is insufficient in the low speed and high load operation region. is there.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an intake system for a multi-cylinder internal combustion engine that can ensure a sufficient intake charge efficiency in a wide operating range.

<Means for Solving Problems> Therefore, according to the present invention, an on-off valve provided at one inlet of a branch passage portion which is independently connected to different cylinders and communicates with each other, and the branch passage portion. An intake air heating heater provided at the other inlet, a resonance passage communicating with the opening / closing valve and a branch passage portion downstream of the heater, and a control unit for controlling opening / closing of the opening / closing valve according to an engine operating state. I did it.

<Operation> In this way, in a predetermined operation region, by closing the on-off valve, intake air is introduced into one branch passage portion through the other branch passage portion and the resonance passage to perform resonance supercharging. Further, in other operating regions, intake valves are introduced into each cylinder through the respective branch passage portions without passing through the resonance passage by opening the opening / closing valve.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, a six cylinder diesel engine will be described.

In the figure, a diesel engine 1 has an exhaust turbocharger 2
Is provided, and the intake duct 3 is attached to the discharge port of the compressor 2a of the exhaust turbocharger 2. The upstream end of the intake manifold 4 is connected to the downstream end of the intake duct 3. A first branch passage portion 5 and a second branch passage portion 6 are formed in the intake manifold 4 in a branched manner. The first branch passage portion 5 is connected to a first cylinder group including # 1 cylinders to # 3 cylinders, and the second branch passage portion 6 is connected to a second cylinder group including # 4 cylinders to # 6 cylinders. ing. here,
The injection order is # 1 cylinder- # 4 cylinder- # 2 cylinder- # 6 cylinder-
The cylinders are # 3 cylinder to # 5 cylinder, and the intake strokes of the cylinders of the first cylinder group and the second cylinder group do not overlap.

An intake shutter 7 as an opening / closing valve is provided at the inlet of the first branch passage 5, and an electric heater 8 for heating the intake is provided at the inlet of the second branch passage 6. An intermediate portion between the first branch passage portion 5 and the second branch passage portion 6 communicates with each other via a resonance passage 9.

The intake shutter 7 is connected to the rod of the pressure-responsive actuator 10 via a link mechanism. Air can be supplied to the pressure chamber of the responsive actuator 10 of this pressure from an air tank 12 via an air passage 11. A three-way solenoid valve 13 is installed in the air passage 11, and this three-way solenoid valve is installed.
13 is driven by a control signal from a control device 14 as control means.

Detection signals are input to the control device 14 from a load sensor 16 that detects an engine load from a control rack position of the fuel injection pump 15 and a rotation speed sensor 17 that detects an engine rotation speed.

Reference numeral 18 is an exhaust manifold, 19 is an air cleaner, 20 is a muffler, and 2b is a turbine of the exhaust turbocharger 2.

Next, the operation will be described.

The control device 14 determines from the map whether the engine operating state is the opening timing or the closing timing of the intake shutter 7 based on the detection signals input from the load sensor 16 and the rotation speed sensor 17. As shown in FIG. 3, this map is set in correspondence with the engine load of the engine rotation speed, and the intake shutter 7 is closed in the low speed / high load operation region and the intake shutter 7 is opened in the other operation regions. Is set to. Further, the intake shutter 7 is closed at low temperature starting.

Then, when the engine operating state is in the low temperature / high load operating region, the control device 14 energizes the three-way solenoid valve 13. As a result, air is supplied to the actuator 10, and the intake shutter 7 is closed by the actuator 10.

Therefore, intake air is introduced into the first branch passage portion 5 through the second branch passage portion 6 and the resonance passage 9, so that resonance supercharging is performed in the resonance passage 9. As a result, in the low speed / high load region, the intake charge efficiency can be increased as indicated by the solid line A in FIG. 5, so that the intake flow rate is increased and the engine output is improved and the smoke emission amount is reduced.

On the other hand, in the operating region other than the low speed / high load operating region, the intake shutter 7 is opened, so the intake air does not pass through the resonance passage 9 to the respective cylinders from the first and second branch passage portions 5 and 6. be introduced. This reduces passage resistance and reduces
Since the pumping loss in the medium load operation region and the high speed operation region can be reduced, the intake charging efficiency can be maintained satisfactorily as indicated by the solid line B in FIG. 5, and the engine output and the fuel consumption can be improved. Therefore, the intake charging efficiency can be improved in a wider operating range than the conventional example.

Further, since the intake shutter 7 is closed at the time of low temperature starting, all the intake air passes through the single electric heater 8 for intake air heating and is supplied to each cylinder. Can be realized.

In addition, the low speed / high load operation range in which the intake shutter 7 is closed is
It may be set by the control rack position and boost pressure as shown in FIG. Further, the engine load may be detected by the depression angle of the accelerator pedal.

<Effects of the Invention> As described above, the present invention is provided with an opening / closing valve which is opened / closed according to the engine operating state at one inlet of the intake manifold and an intake air heater at the other inlet of the branch passage. And the branch passage is communicated with the resonance passage, the intake charging efficiency can be increased in a wide operating range to improve the engine output and the fuel consumption. Also,
The intake air can be heated by a single heater, and the cost can be reduced while maintaining good startability.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a side view of the same as above, FIG. 3 is a characteristic diagram for explaining the operation of the same, FIG. 4 is another characteristic diagram, and FIG. The figure is for explaining the drawbacks of the conventional example and the operation of the embodiment. 4 ... intake manifold, 5 ... first branch passage, 6 ...
… Second branch passage, 7 …… Intake shutter, 8 …… Electric heater, 9 …… Resonance passage, 14 …… Control device

Claims (1)

[Scope of utility model registration request] 1. A multi-cylinder internal combustion engine having an intake manifold provided with two branch passages that are connected to different cylinders independently of each other, and an on-off valve provided at the inlet of the one branch passage. A control for controlling opening / closing of the intake air heating heater provided at the other branch passage inlet, a resonance passage communicating with the opening / closing valve and the branch passage downstream of the heater, and the opening / closing valve according to the engine operating state. An intake device for a multi-cylinder internal combustion engine, comprising: