JPS62103418A - Turbosupercharger - Google Patents

Abstract

PURPOSE:To reduce a diameter of an exhaust passage leading to a turbine and improve supercharging efficiency at a low speed range as well as to prevent exhaust interference between cylinders from occurring, by dividing a flow of exhaust gas, which has the turbine bypassed at the time of high speed, in and around an exhaust port. CONSTITUTION:Exhaust gas is fed to a turbosupercharger 6 from each exhaust port 3 of plural cylinders 2a-2d via exhaust passages 13 and 14. In addition there is provided with a by-cylinder bypass passage 16 being opened to the exhaust passage in and around each exhaust port 3 of these cylinders, whereby passages themselves corresponding to such cylinders that an exhaust stroke is uncontinued are converged respectively, and a bypass valve 17 is installed in this converging part. With this constitution, an exhaust passage system ranging from the vicinity of the exhaust port to a turbine is able to be smaller as far as a portion for corresponding to an exhaust gas bypassing quantity at a high speed range, thus supercharging efficiency at a low speed range is improvable. In addition, such a possibility that exhaust interference occurs between cylinders whose exhaust strokes are continued is preventable.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an exhaust turbocharging device, and more particularly to a gastrointestinal system in which the structure of the exhaust system for the turbine of a turbocharger is improved in order to improve turbocharging efficiency. It is.

(Prior art) Conventional general exhaust turbocharging devices are equipped with an exhaust passage that collects exhaust gas from multiple cylinders and guides it to the turbine of the turbocharger. In order to prevent overcharging, the system is equipped with a bypass passage that bypasses the turbine and a bypass valve that opens and closes this bypass passage, and when the boost pressure reaches a set value, the bypass valve is closed. A portion of the exhaust gas is allowed to escape into the bypass passage. The bypass valve is usually formed integrally with the turbine housing, and its upstream end opens into the turbine housing immediately upstream of the turbine.

In addition, as shown in Japanese Utility Model Application Publication No. 56-6F3028, the exhaust system is divided into two exhaust passages, and the exhaust gases from half the cylinders are collected and guided independently to the turbine, thereby reducing the exhaust gas. Some devices use dynamic pressure to improve turbocharger drive efficiency, but even in this device, the upstream end of the bypass passage is divided into two parts for the turbine's direct flow, or is connected to the I air introduction passage. It's open.

In such a device, the exhaust passage from exhaust bow 1 to the vicinity of the turbine has a relatively large diameter so that the entire amount of gas from each cylinder can sufficiently flow even at high speeds with a large amount of active gas. The exhaust gas flow rate is increased by narrowing the passage to some extent just before the turbine. However, with this structure, in a low speed range where the amount of exhaust gas is small, the exhaust gas expands in the exhaust passage, reducing exhaust energy, and even if the passage is narrowed just before the turbine, energy loss occurs. For this reason, it is desirable to reduce the diameter of the exhaust passage in order to increase supercharging efficiency in the low speed range, but as mentioned above, until now it was necessary to circulate the entire amount of exhaust gas at high speeds, so it was necessary to My job is to reduce the diameter of the passageway.

(Objective of the Invention) In view of the above circumstances, the present invention reduces the diameter of the exhaust passage that guides the antagonist gas to the turbine by diverting the exhaust gas that bypasses the turbine at high speed near the IJI air bow 1. An object of the present invention is to provide an exhaust turbo supercharging device that can increase supercharging efficiency in a low speed range by a technique, and can prevent exhaust interference between cylinders when doing so.

(Structure of the Invention) The present invention provides an exhaust passage for guiding exhaust gas from exhaust ports of a plurality of cylinders to a turbine of a turbocharger, a bypass passage for guiding exhaust gas by bypassing the turbine, and opening/closing of this bypass passage. to control the boost pressure to the engine l'? l
- In the exhaust turbo supercharging device equipped with a bypass valve, the bypass passage is formed with a cylinder-specific bypass passage whose upstream end opens into the exhaust passage near the exhaust port of each cylinder, and the cylinder-specific bypass passage The passages corresponding to the cylinders whose exhaust strokes are not consecutive are gathered together, and bypass valves are provided at these gathering parts.

In other words, by bypassing the exhaust gas near the exhaust port, the diameter of the exhaust passage from the vicinity of the exhaust port to the turbine can be reduced by an amount commensurate with the amount of exhaust gas bypass at high speeds, and the exhaust stroke can be reduced. By combining cylinder-specific bypass passages corresponding to non-consecutive cylinders and providing a bypass valve there, it is possible to avoid exhaust interference between cylinders whose exhaust strokes are continuous via the bypass passage. .

(Embodiment) Fig. 1 shows an embodiment in which the present invention is applied to a four-cylinder engine, where 1 is the engine, 28 to 2d are each cylinder of the engine 1, and 3 is an exhaust port of each cylinder 2a to 2d. , a cylinder-specific exhaust passage 4 communicating with the exhaust port 3 of each cylinder 2a to 2d.
are collected in the exhaust manifold 5. A turbine 7 of a turbocharger 6 is installed downstream of the exhaust manifold 5 and housed in a turbine housing 8 . As is well known, in the turbocharging 1fi6, a turbine 7 is driven by exhaust gas, and a compressor 10 is connected to the turbine 7 via a shaft 9.
rotates to supercharge engine 1 with intake air.

In addition, in this embodiment, in order to increase the supercharger drive efficiency by utilizing the dynamic pressure of the exhaust, partition walls 11 and 12 are provided extending from the exhaust passage collection part in the exhaust manifold 5 to the inside of the turbine housing 8. , the exhaust gas from each half of the cylinders is collected and independently connected to the turbine 7.
Two systems of exhaust passages 13 and 14 are configured.

When configuring two exhaust passages 13, 14 in this way, the first and second exhaust passages have non-continuous exhaust strokes. Exhaust passages 4 for each cylinder of the fourth cylinders 2a, 2d and the second. Third cylinder 2b.

The exhaust passages 4 for each cylinder of 2G may be grouped together, but as shown in the figure, the
．． The exhaust passages 4 for each cylinder of the second cylinders 2a and 2b and the third cylinder. The cylinder-specific exhaust passages 4 of the fourth cylinders 2C and 2d may be assembled together. According to the illustrated exhaust system, the residual pressure of the exhaust from one of the cylinders in which exhaust strokes are continuous increases the dynamic pressure of the exhaust from the other cylinder, and this dynamic pressure is applied to the turbine 7.
This increases drive efficiency.

Reference numeral 15 denotes a bypass passage that bypasses the turbine 7 and guides the υ1 air gas. A passage 16 is provided. These bypass passages 16 for each cylinder are grouped together corresponding to cylinders whose exhaust strokes are not continuous, that is, bypass passages 16 for each cylinder corresponding to the first cylinder 2a and the fourth cylinder 2d, and the bypass passages 16 for each cylinder corresponding to the second cylinder 2b Bypass passages 16 for each cylinder corresponding to and the third cylinder 2C are gathered together, and these two bypass passage collection parts 17 form a common bypass passage 18 on the downstream side.
is connected to. A downstream end of the common bypass passage 18 opens into an exhaust passage 19 downstream of the turbine 7 . Both of the bypass passage gathering parts 17 are opened and closed by a bypass valve 20, respectively, and in the embodiment shown in the figure, a common bypass valve 20 is used.
Figures 2 and 3 show the specific structure of the main parts.

As shown in these figures, the above-mentioned bypass passage 1 for each cylinder
6 is formed integrally with the exhaust manifold 5, and both of the bypass passage gathering portions 17 open into a valve chamber 21 attached to the exhaust manifold 5, and a common bypass passage 18 is connected to this valve chamber 21. A bypass valve 20 rotatably attached to the valve chamber 21 via a shaft 22 opens and closes the respective openings of the bypass passage gathering portions 17 to the valve chamber 21 at the same time. The bypass valve 20 is opened by an actuator 23 that operates in accordance with the boost pressure when the boost pressure reaches a set value.

In this turbocharger, in a low speed range where the amount of exhaust gas is small and the boost pressure is lower than the set value, the bypass passage 15 is closed by the bypass valve 20.
Exhaust gas from each cylinder 2a to 2d is turbocharged 1fi6
In high-speed ranges where the amount of iJl gas is large, the bypass valve 2 is guided as the boost pressure reaches the set value.
0 is opened, and part of the exhaust gas from each cylinder 2a to 2d is bypassed downstream of the turbine 7 through the cylinder-specific bypass passage 16 and the common bypass passage 18, thereby controlling the maximum boost pressure. In this case, the exhaust gas is bypassed from the vicinity of the V1 air port 3, so that the downstream IJI air passage 4 and J: cylinder air passage 13.14
should be made thin enough to allow the flow of exhaust gas excluding the exhaust gas bypass amount in the high speed range. Therefore, in a low speed range with little exhaust gas suspension, exhaust energy is prevented from decreasing in the exhaust passage, and the exhaust energy can be effectively applied to the turbine 7 to increase supercharging efficiency.

Furthermore, as in this embodiment, the exhaust system has two exhaust passages 13.
．． When divided into 14 parts, the synergistic effect of utilizing the dynamic pressure of the exhaust gas and reducing the diameter of the exhaust passage described above further increases the supercharging efficiency in the low speed range.

In addition, when opening the cylinder-specific bypass passage 16 near the exhaust boat 3 as described above, especially in the low speed range, the cylinder-specific bypass passage 16 corresponding to the cylinder with consecutive IJI strokes is
When these cylinders communicate, exhaust interference occurs, which means that during the period when 11 strokes overlap between these cylinders, high-pressure exhaust gas from the cylinder immediately after the start of the exhaust stroke is brought into the cylinder just before the end of the exhaust stroke, resulting in exhaust blowback. However, in the present invention, the cylinder-specific bypass passages 16 corresponding to the cylinders in which the υ1 exhaust strokes are not consecutive are assembled and the bypass valves 20 are provided here, so that the cylinder-specific bypass passages 16 corresponding to the cylinders in which the exhaust strokes are consecutive are collected. Since communication is avoided in the low speed range, the above-mentioned exhaust interference can be prevented.

In order to prevent the above-mentioned exhaust interference, it is conceivable to provide a bypass valve 20 in each cylinder-specific bypass passage 16, but in this case, more bypass valves 20 are required for each cylinder. In contrast, in the present invention, since the bypass valve 20 is provided in the bypass passage collecting section 17,
The structure can be simplified. In this case, bypass valves 20 may be provided separately in both bypass passage gathering portions 17;
If the common bypass valve 20 is used to open and close both the bypass passage gathering portions 17 as in the above embodiment, the structure can be further simplified.

(Effects of the Invention) As described above, in the present invention, the upstream end of the bypass passage for each cylinder is opened near the exhaust bow 1 of each cylinder, so that the exhaust passage system from the exhaust bow 1 to the turbine can be operated at high speed. This can be reduced by an amount commensurate with the amount of gas bypass in the range tJl, thereby increasing the supercharging efficiency in the low speed range. In addition, the bypass passages corresponding to the cylinders whose exhaust strokes are not consecutive are assembled together at u', and these gathering parts are opened and closed by bypass valves, so that the exhaust stroke can be controlled even though the structure is simple. This prevents exhaust interference between consecutive cylinders and prevents a decrease in output due to exhaust blowback.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is a sectional view showing the specific structure of the main part, and FIG. 3 is a sectional view taken along the line 1--2 in FIG. 1...Engine, 2a-2d...Cylinder, 3...Exhaust bow 1-. 4... Exhaust passage by cylinder, 13.14...
- Exhaust passage, 15... Bypass passage, 16... Bypass for each cylinder = 11- passage, 20... Bypass valve. Patent applicant: Mazda Co., Ltd. Agent Patent attorney: Etsushi Kotani Patent attorney: Masamuki Tsuzuki Patent attorney: Itaya
Primitive Man Figure 2 Figure 1 Figure 3 [1

Claims (1)

[Claims] 1. An exhaust passage that guides exhaust gas from the exhaust ports of multiple cylinders to the turbine of a turbocharger, a bypass passage that bypasses the turbine and guides the exhaust gas, and supercharging the engine by opening and closing this bypass passage. In the exhaust turbo supercharging device equipped with a bypass valve for controlling pressure, the bypass passage is formed with cylinder-specific bypass passages each having an upstream end opening into an exhaust passage near the exhaust port of each cylinder. An exhaust turbo supercharging device characterized in that passages corresponding to cylinders whose exhaust strokes are not consecutive among the bypass passages are assembled together, and bypass valves are provided at these gathering parts.