JPS62247122A - Internal combustion engine with mechanical type supercharger - Google Patents

Abstract

PURPOSE:To reliably prevent leak of vibration and noise, caused by intake air pulsation, to the outside, by a method wherein a supercharging intake air cooling means is disposed to the interior of a surge tank located in the middle part of an intake air passage situated down a line from a mechanical supercharger. CONSTITUTION:An airflow meter 4, a throttle valve 5, a root blower type supercharger 6, a surge tank 7, and a fuel injector 8 are situated, in order named, from the upper stream side in an intake air passage 3 leading from an air cleaner 1 to an intake air port 2. In the engine with a supercharger, an intercooler 18, adapted to cool supercharging intake air, is disposed in the surge tank 7, and vibration noise, generated resulting from vibration of the fin of the intercooler 18 occasioned by pulsation of supercharging intake air, is prevented from leak to the outside. The intercooler 18 is connected to a radiator 21 for an intercooler, and is situated so that the supercharging intake air is cooled by means of cooling water circulated through driving of a water pump 22.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an internal combustion engine with a mechanical supercharger, and particularly to one equipped with a supercharged intake air cooling means.

(Prior art) Conventionally, in internal combustion engines for automobiles, an exhaust turbo supercharger or a mechanical supercharger driven by the power of the crankshaft is installed in the middle of the intake passage in order to increase the intake air filling amount and increase the output. Many also have feeding machines.

In the above-mentioned exhaust turbo supercharger, the rotation speed is extremely high and the intake air is discharged almost continuously, so there is no pulsation in the supercharged intake, but with a mechanical supercharger (displacement supercharger) The problem is that intake air is discharged periodically and its rotational speed is lower than that of an exhaust turbo supercharger, which causes pulsation in the supercharged intake air, and this intake pulsation causes the intake pipe and surge tank to vibrate, causing vibration noise. There is.

In order to reduce this vibration noise, for example,
No. 65928 discloses that a cylindrical surge tank is interposed in the intake passage on the downstream side of the positive displacement supercharger, and the end plate of the surge tank is composed of a double flat plate connected by reinforcing ribs, so that the intake air A supply air noise reduction device is described that reduces noise generated from a surge tank due to pulsation.

By the way, even when installing the above-mentioned mechanical supercharger,
As the supercharging pressure downstream of the supercharger increases, the temperature of the intake air increases, so it is necessary to provide an inturner to cool the supercharged intake air in order to prevent a decrease in charging efficiency.

Conventionally, when installing the above-mentioned ink roller, it has generally been installed in a portion of the intake passage between the supercharger and the surge tank.

(Problems to be Solved by the Invention) As described above, when a mechanical supercharger is provided and an intercooler is interposed in the intake passage on the downstream side, it is necessary to form a thin metal plate with a large surface area. There is a problem in that the fins of the ink cooler vibrate due to the intake pulsation of the supercharged intake air, and significant vibration noise is generated from the ink cooler.

In addition, since a fairly large intercooler is installed in the middle of the intake passage, there are problems such as requiring installation space for the ink cooler and complicating the structure of the connection between the intake passage and the intercooler. be.

(Means for Solving the Problems) An internal combustion engine with a mechanical supercharger according to the present invention has a mechanical supercharger interposed in the middle of an intake passage, and a part of the intake passage downstream of the supercharger. A surge tank is provided in the middle of the pump, and supercharged intake air cooling means is provided inside the surge tank.

(Function) In the mechanical supercharger 4=J internal combustion engine according to the present invention,
A mechanical supercharger is installed in the middle of the intake passage, and a surge tank is installed in the middle of the intake passage downstream of the supercharger.
Since the supercharged intake air cooling means is disposed inside the surge tank, the vibration noise generated from the supercharged intake air cooling means due to intake pulsation is blocked and attenuated by the surge tank, and almost no leakage to the outside occurs.

(Effects of the Invention) According to the internal combustion engine with a mechanical supercharger of the present invention, since the supercharged intake air cooling means is disposed in the surge tank as explained above, the supercharged intake air is cooled by the pulsation of the supercharged intake air. It is possible to reliably prevent the vibration noise generated from the means from leaking to the outside and reduce the noise.

Furthermore, by simply increasing the size of the surge tank, the supercharged intake air cooling means can be placed inside the surge tank, which eliminates the need for special space for the supercharged intake air cooling means and eliminates the need for the supercharged intake air cooling means within the engine room. This is advantageous not only in terms of the arrangement of equipment, but also in terms of the structure in which the supercharged intake air cooling means is attached to the intake passage.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

The mechanical supercharged engine according to this embodiment is a vertical four-cylinder ignition type engine for an automobile, and FIG. 1 shows a configuration diagram of an intake system and a cooling system of this engine E.

As shown in FIG. 1, from the air cleaner 1 to the intake boat 2
An air flow meter 4, a throttle valve 5, a Roots blower type supercharger 6, a surge tank 7, and a fuel injector 8 are interposed in the intake passage 3 extending from the upstream side.
A first bypass passage 9 is provided that bypasses the supercharger 6, and an electromagnetic on-off valve 10 is interposed in the first bypass passage 9. A second bypass passage 11 is provided to bypass the surge tank 7, and a switching valve 12 is provided at a branching portion of the second bypass passage 11 to selectively close the second bypass passage 11 and the intake passage 3. The switching valve 12 is switched and driven by an electromagnetic actuator 12a.

The supercharger 6 is interlocked with the crankshaft 13 via a belt 14 and is rotationally driven by the driving force from the crankshaft 13, but an electromagnetic clutch 15 is interposed on the human-powered shaft of the supercharger 6. , by this electromagnetic clutch 15, the crankshaft 13
The driving force can be intermittent. Since the supercharger 6 is relatively small, the crankshaft 13
The pulley ratio of the pulley 17 on the input shaft side with respect to the pulley 1716 on the side is set to be large, so that the mechanical supercharger is driven to rotate at high speed.

Therefore, the maximum temperature of the supercharged intake air from supercharger a6 is approximately 12
Since the temperature is as high as 0.degree. C., an ink cooler 18 is provided to prevent the filling efficiency from decreasing, and this ink cooler 18 is disposed inside the surge tank 7.

The reason why the ink cooler 18 is arranged inside the surge tank 7 is as follows.
This is to prevent the vibration noise generated by the fins of the intercooler 18 from vibrating due to the pulsation of the supercharged intake air from leaking to the outside.

- Because the intercooler 18 is disposed inside the surge tank 7, the surge tank 7 is formed to be somewhat large, and the downstream part of the surge tank 7 from the ink cooler 18 is connected from the intake boat 3 side to the inside of the surge tank 7. The volume necessary to absorb the reverse pressure wave of the propagating intake air (this volume is defined as ■1) is secured, and the surge tank 7 is provided in the upstream portion of the ink cooler 18 of the surge tank 7. The volume (this volume is assumed to be v2) and the length in the intake air flow direction necessary for uniformly flowing the supercharged intake air flowing into the ink cooler 18 into the ink cooler 18 are secured, and the above volume 1 is equal to the above volume v
It is set much larger than 2.

Furthermore, in order to prevent water generated by condensation when the supercharged intake air is cooled by the intercooler 18 from flowing into the combustion chamber of the engine E, a water drain recess 19 is provided in the bottom wall of the surge tank 7 over almost the entire width. is formed, and an electromagnetic on-off valve 20 is interposed in the drain pipe at the bottom of the drain recess 19.

The ink cooler 18 is an intercooler radiator 21
The lower tank of the radiator 21 is connected to the upper tank 18a of the intercooler 18 through a pipe 23 having a water pump 22, and the lower tank 18b of the intercooler 18 is connected to the upper tank of the radiator 21 through a pipe 24, and the radiator 21 The air-cooled cooling water is pumped to the ink cooler 18 by the water pump 22, and the supercharged intake air is cooled by the ink cooler 18 and then circulated from the ink cooler 18 to the radiator 21.

The ink cooler 18 includes, for example, an upper tank 18a, a lower tank 18b, and both tanks 18 as shown in FIG.
A large number of thin metal plate fins 18c are provided horizontally between a and 18b at intervals of several millimeters, and a plurality of fins 18c are provided vertically through the fins 18c to communicate and connect the upper tank 18a and the lower tank 18b. Although the structure is made up of a connecting tube (not shown), it is not limited to this structure, and various existing ink coolers may be used (or an air-cooled intercooler may be used).

A control unit 25 is provided to control the various valves 10, 12, 20, water pump 22, etc. based on the operating state of the engine E, the outside temperature, the engine cooling water temperature, etc. , an intake air amount signal from the air flow meter 4, an intake air temperature signal from the intake air temperature sensor 26, a cooling water temperature signal from the cooling water temperature sensor 27, a signal from the level sensor 28 provided in the water drain recess 19, etc. The control unit 25 controls the electromagnetic on-off valve 10 and the electromagnetic clutch 1.
5. The electromagnetic actuator 12a for the switching valve 12, the water pump 22, and the electromagnetic on-off valve 20 are controlled. This control unit 25 is mainly based on a microcomputer, and the control program for controlling the above-mentioned control objects is input and stored in advance in the ROM (read-only memory) of the microcomputer, but the content of the control is relatively simple. Therefore, it will be explained in conjunction with the explanation of the function below. In the drawing, reference numeral 29 is a radiator for cooling the cylinder block 30 and cylinder head 31 of the engine E, and reference numeral 32 is a cooling water circulation pump.

Next, the operation of the mechanical supercharged engine having the above configuration will be explained.

When engine E is started or under low load, there is no need to supercharge the intake air, and the output is consumed by driving the supercharger 41!6, and when the intake air passes through the intercooler 1B, the intake resistance increases accordingly. From this, intake air is supplied without operating the supercharger 6.

In this case, the electromagnetic clutch 15 is disconnected, the supercharger 6 is stopped, the electromagnetic on-off valve 10 is opened, and the switching valve 1 is opened.
2, the intake passage 3 to the surge tank 7 is closed, and the water pump 22 is held in a stopped state.

Therefore, the intake air flows through the air flow meter 4, the throttle valve 5, the first bypass passage 9, and the second bypass passage 11.

When the throttle valve 5 is opened to a certain extent and the load becomes medium or higher, the supercharger 6 is operated to supply supercharged intake air via the intercooler 18.

In this case, the electromagnetic clutch 15 is connected, and the electromagnetic on-off valve 1
0 is closed, and the second bypass passage 11 is closed by the switching valve 12.

Therefore, the intake air passes through the air flow meter 4 and the throttle valve 5 and is supercharged by the supercharger 6, and this supercharged intake air at about 100°C to 120°C flows into the surge tank 7 and is cooled by the intercooler 18, after which the surge Air is drawn from the tank 7 through the intake passage 3 into the intake boat 2 of each cylinder.

As mentioned above, when the intake air is supercharged by the supercharging 413!6, it is intermittently discharged from the supercharger 6, so an intake pulsation (pressure fluctuation) occurs in the supercharged intake air, and this intake pulsation causes ink Although the fins 18c of the cooler 18 vibrate and generate vibration noise, the intercooler 7 is surrounded by a relatively thick surge tank 7 made of a cast product with a large f quantity and high rigidity, so the vibration noise generated from the ink cooler 18 is suppressed. There is almost no leakage to the outside of the surge tank 7, and the surge tank 7 effectively blocks the leakage.

On the other hand, as a result of the intermittent intake by supercharging [6, intake pulsation also occurs in the intake air on the upstream side of supercharging 4 m6,
Since the throttle valve 5 is interposed in the intake passage 3 on the upstream side of the supercharger 6, the above-mentioned intake pulsation is also effectively blocked by the throttle valve 5, and the air cleaner case etc. are prevented from vibrating due to the above-mentioned intake pulsation. It looks like this. Further, when water accumulates in the drain portion 19 to a predetermined level, the electromagnetic on-off valve 20 is opened while the engine is stopped to drain the water.

As described above, by cooling the supercharged intake air heated as a result of supercharging by the mechanical supercharger 6 with the intercooler 18, the charging efficiency is increased, the engine output is improved, and the combustion temperature in the combustion chamber is increased. It is possible to prevent this and reduce NOx in exhaust gas.

Note that when the outside air temperature is low, the temperature of the supercharged intake air does not become very high, so the supercharged intake air is not passed to the intercooler 18 but is supplied through the second bypass passage 11 radially.

Here, the above embodiment may be partially modified as follows.

(1) In order to be able to warm the intake air with the intercooler 18 when the outside temperature is low or before warming up,
The hot water flowing into the radiator 29 or the hot water cooled by the radiator 29 is transferred to the ink cooler 18 by switching the valve.
It is configured so that it can be circulated to

(2) As shown in FIG. 3, the ink cooler faces the man lower a of the surge tank 7 so that the supercharged intake that has flowed into the surge tank 7 from the intake passage 3 flows uniformly over the entire surface of the intercooler 18. At the center of the intercooler 18, the intervals between the wavy fins are narrowed to increase the resistance, and at the sides of the intercooler 18, the intervals between the wavy fins are widened to reduce the resistance.

(3) As shown in FIG. 4, before the inlet lower a of the surge tank 7 is formed so that the supercharged intake flowing into the surge tank 7 from the intake passage 3 flows uniformly over the entire surface of the ink cooler 18. The wall 7b is formed into a tapered shape.

(4) As shown in FIG. 5, a guide plate is installed near the inlet lower a of the surge tank 7 so that the supercharged intake flowing from the intake passage 3 into the surge tank 7 flows uniformly over the entire surface of the ink cooler 18. 33 will be provided.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a configuration diagram of an intake system and cooling system of an automobile engine with a mechanical supercharger, and FIG. 2 is a partially cutaway perspective view of an ink cooler and a surge tank. , and FIGS. 3 to 5 are schematic cross-sectional views of a surge tank and an ink cooler according to modified examples, respectively. 3. Intake passage, 6. Roots blower type mechanical supercharger, 7. Surge tank, 18. Ink cooler,
21...Radiator for intercooler, E...Engine. Patent applicant Mazda Motor Corporation 9jSZ diagram Figure 4

Claims (1)

[Claims] (1) A mechanical supercharger installed in the middle of the intake passage,
Mechanical supercharging characterized by comprising: a surge tank provided in the middle of the intake passage on the downstream side of the supercharger; and supercharged intake air cooling means disposed inside the surge tank. Internal combustion engine.