JPS62103419A - Turbosupercharged engine - Google Patents

Abstract

PURPOSE:To reduce an energy loss in an exhaust passage leading to a turbine as well as to aim at improvement in supercharging efficiency at a low speed range, 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:An exhaust passage 6a of an exhaust manifold 6 for respective cylinders 2a-2d is branched off into first exhaust passages 7a-7d and second exhaust passages 8a-8d. Downstream ends of the first exhaust passage are converged together and interconnected to a turbine 14, while the second exhaust passage is interconnected to a bypass passage 11 via bypass valves 10a-10d. With this constitution, exhaust gas to be bypassed by these bypass valves will not pass the whole stroke of these exhaust passages to the extent of the turbine, so that there is no increase in passage resistance, thus these exhaust passages are throttled and supercharging efficiency at a low speed range is improvable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a turbocharged engine, and particularly to an improvement in the exhaust passage configuration for improving supercharging efficiency.

(Prior art) Conventional turbocharged engines are equipped with an exhaust passage that collects exhaust gas from multiple cylinders and guides it to the turbocharger, and the supercharging pressure to the engine increases too much at high speeds. In order to prevent this, a bypass passage that bypasses the turbine and a bypass valve that opens and closes this bypass passage are provided. When the boost pressure reaches a set value, the bypass valve is opened and a part of the exhaust gas is bypassed. I try to let them escape into the aisle. The bypass valve is usually integral with the turbine housing, and its upstream end opens into the turbine housing immediately upstream of the turbine.

For example, as shown in FF11 Publication No. 56-66028, the exhaust system is divided into two exhaust passages, and a half 'fI
There is a type that aims to improve the supercharger drive efficiency by using the dynamic pressure of the exhaust gas by collecting the exhaust gas from each cylinder and guiding it to the turbine independently.
Also in this device, the upstream end of the bypass passage opens into the two-divided exhaust gas introduction passage immediately upstream of the turbine.

In such a device, the bypass passage from the exhaust port to the vicinity of the cylinder can sufficiently circulate the entire amount of exhaust gas from each cylinder even at high speeds when the amount of exhaust gas is large. It is designed to narrow the passage to some extent just before the turbine to increase the exhaust flow velocity. However, with this structure, in the low-speed range where the amount of exhaust gas is small, the JJI gas expands in the JJI air passage and the exhaust energy is low -F t, passing through the passage just before the turbine. Even if I squeeze it, the energy is still 1].

In order to increase supercharging efficiency in the low speed range, it is desirable to reduce the diameter of the exhaust passage. The inner valve was used to reduce the ventilation diameter.

(Purpose of the Invention) The present invention has been made in view of the above-mentioned problems of the conventional technology, and by diverting the exhaust gas that bypasses the turbine at high speed near the exhaust port, the tJl gas is guided to the turbine. An object of the present invention is to provide a turbocharged engine capable of reducing energy loss in an exhaust passage and improving supercharging efficiency in a low speed range.

(Structure of the Invention) The present invention provides an exhaust passage for guiding exhaust gas from exhaust ports 1 to 1 of a plurality of cylinders to a turbine of a turbocharger, a bypass passage for guiding exhaust gas by bypassing the turbine, and the bypass passage. In a turbocharged engine equipped with a bypass valve that opens and closes to control supercharging pressure to the engine, the exhaust passage is branched into a first exhaust passage and a second exhaust passage from an exhaust port I for each cylinder. The downstream ends of the first exhaust passages are gathered together and communicated with the turbine, and the second exhaust passages are communicated with the bypass valve.

With this configuration, exhaust gas discharged from exhaust ports 1 to 1 of each cylinder passes through the first exhaust passage, and is then collected at the downstream end of this first exhaust passage and sent to the turbine. A portion of the exhaust gas is discharged to the outside via the second exhaust passage and the bypass passage. Therefore, at low speeds, exhaust gas passes only through the first exhaust passage, so
Energy loss due to exhaust pressure applied to the turbine is reduced.

(Embodiment) FIG. 1 is a configuration diagram of a turbocharged engine according to an embodiment of the present invention. In the figure, a resin main body 1 has a cylinder block 2, and this cylinder block 2 has four cylinders 2a, 2b, and 2c.

2d are installed respectively. , L cylinder 2a.

2b, 2c, and 2d have intake ports 1 to 3a, 3b, 3c, and 3d for sending fuel for injection to the combustion chamber, and an exhaust port 4a for discharging combustion gas from the combustion chamber.

4b, 4c, and 4d are connected.

Intake port 3a in the engine main body 1.

3b, 3c, and '3d are connected to intake passages 5a, 5b, 5c, and 5d provided in the intake manifold 5, respectively. The exhaust ports 4a, /lb, 4C, 4d are exhaust passages 6a, 6b, 6 provided in the exhaust manifold 6.
c, connection to 6d, exhaust passages 6a, 6b, 6c, 6
d is branched midway into first exhaust passages 7a, 7b, 7c, and 7.
d and second exhaust passages 8a, sb, 8c, and 8d.

The first exhaust passages 7a, 7b, 7c, and 7d are provided in the exhaust -z second hold 6, and the eleventh exhaust passage 7a.

The downstream ends of 7b, 7c, and 7d are connected to the exhaust passage 9 and brought together. Second exhaust passage 8a.

Bypass valves 10a, 10b, IOC, and 10d are provided at the downstream ends of the second exhaust passages 8b, 8c, and 8d to communicate with them, respectively, and these second exhaust passages 8a, 8b, 8c, and 8d are connected to the exhaust passage 12 through the bypass passages. It is connected to the. The turbocharger 13 has a turbine 14 and a compressor 15 linked to the turbine 14. The turbine 14 is provided between the exhaust passages 9 and 12, and the compressor 15 is provided between the intake passages 16 and 17. . The downstream end of the intake passage 17 is connected to an intake passage 18 that connects the flow ends of each of the intake passages 5a, 5b, 5c, and 5d (7). A 1ζth throttle valve 19 is provided on the downstream side of the intake passage 17 to control the amount of intake air.

The control unit 20 detects the air boost pressure in the intake passage 17 and performs predetermined calculations, and the bypass valve 10a,
10b, 10c, and 10d, respectively.

Next, the operation of this embodiment will be explained.

In a low speed range where the amount of exhaust gas is small and the supercharging pressure in the intake passage 17 is lower than the set value, the bypass valve 10a is activated.

J to 10b, 10c, and 10d: With the rebypass passage 11 closed, each cylinder 2a, 2t), and 2G.

Exhaust gas from 2d flows into turbine 1 of turbocharging 1113
Guided by 4. On the other hand, in high-speed ranges where the amount of exhaust gas is large, the boost pressure is set (as it reaches 0, the bypass valves 10a and 1
0b, 10c, and 10d are opened, and each cylinder 2a,
Part of the exhaust gas from 2b, 2c, and 2d passes through the bypass passage 11 and is bypassed to the exhaust passage 12, thereby controlling the maximum boost pressure. In this case, exhaust bows 1 to 4a
, 4b.

Since the exhaust gas is bypassed from the vicinity of 4c and 4d,
First exhaust passages 7a, 7b, 7c, 7d and exhaust passage 9
The exhaust gas is distributed except for the exhaust gas bypass amount in the high speed range1! This can be done by making the exhaust gas thin enough to prevent the exhaust resistance from increasing rapidly in the high speed range.

Therefore, in the low speed range where the amount of exhaust gas is small, the decrease in exhaust energy in the exhaust passage is suppressed, responsiveness is improved, and the exhaust energy can be effectively applied to the turbine to increase supercharging efficiency. .

FIG. 2 is a configuration diagram of a turbocharged engine according to another embodiment of the present invention. In FIG. 2, components corresponding to those shown in FIG. 1 are given the same reference numerals. In FIG. 2, an engine main body 1 has a cylinder block 2, and this cylinder block 2 has four cylinders 2a, 2b, 2c.
, 2d are provided, respectively. The above cylinder 2. a,
2b, 2C.

2d is an intake port 3 for sending injected fuel to the combustion chamber.
a, 3b, 3c, 3d, and combustion chamber) exhaust ports 1 to 4a, 4b, 4c for discharging combustion scum.

4d is connected.

Intake port 3a in the engine main body 1.

3b, 3c, and 3d are connected to intake passages 5a, 5b, 5c, and 5d provided in the intake manifold 5, respectively. The exhaust ports 4a, 4b, 4c, 4d are exhaust passages 6a, 6b, 6c provided in the exhaust manifold 6,
6d, the exhaust passages 6a, 6b, 6c, and 6d are branched in the middle and are connected to the second exhaust passages 7a, 7b, 7c, and 7d.
It is connected to exhaust passages 8a, 8b, 8c, and 8d.

The first exhaust passages 7a, 7b, 7c, and 7d are provided in the exhaust manifold 6, and the first exhaust passages 7a.

The downstream ends of 7b, 7c, and 7d are connected to the exhaust passage 9 and brought together. Second exhaust passage 8a.

The downstream ends of the exhaust passages 8b, 8c, and 8d are connected to a common exhaust passage 8, and the common exhaust passage 8 has a bypass valve 10 that communicates with the second exhaust passages 8a, 8b, '8c, and 8d.
is provided, and this common 11 air passage 8 is a bypass passage 11
It is connected to the exhaust passage 12 via.

The turbocharger 13 is connected to the turbine 14 and this turbine 1/I.
The compressor 15 is linked to the turbine 14.
is arranged between the exhaust passages 9 and 12, and the compressor 15 is arranged between the intake passages 16 and 17. Intake passage 17
The downstream end of is connected to an intake passage 18 that connects the upstream ends of intake passages 5a, 5b, 5c, and 5d. One throttle valve is provided on the downstream side of the intake passage 17 to control the amount of intake air. The control unit 20 detects the air boost pressure in the intake passage 17, performs predetermined calculations, and controls the bypass valve 10.

Next, the operation of this embodiment will be explained.

In a low speed range where the amount of exhaust gas is small and the supercharging pressure in the intake passage 17 is lower than the set value, the bypass passage 11 is closed by the bypass valve 10, and each cylinder 2a, 2b, 2c,
From 2d (D exhaust gas flows into the turbine 1 of the turbocharger 13
Guided by 4. On the other hand, in high-speed ranges where the amount of exhaust gas is large, the bypass valve 10 is opened as the boost pressure reaches the set value, and a portion of the exhaust gas from each cylinder 2a, 2b, 2c, and 2d flows through the bypass passage 11. and is bypassed to the exhaust passage 12, thereby controlling the maximum boost pressure. In this case, since the exhaust gas is bypassed from the vicinity of the exhaust ports 4a, 4b, 4c, 4d, the first exhaust passages 7a, 7b, 7c,
7d and the exhaust passage 9 should be made narrow enough to allow the exhaust gas excluding the exhaust gas bypass amount to flow in the high speed range, and also to prevent a sudden increase in exhaust resistance in the high speed range. can. Therefore, in the low-speed range where the amount of +11 gas is small, the decrease in the 41+1 gas energy in the exhaust passage is suppressed, the response is improved, and the exhaust energy is effectively applied to the turbine to improve supercharging efficiency. can be increased. Also, in this embodiment, only one bypass valve is provided, so the structure of the exhaust passage is compared to the embodiment shown in FIG. 1, in which bypass valves are provided on four sides. It has the advantage of simplifying the process and reducing cost.

Note that although the present invention is applied to a four-cylinder engine, it may be applied to engines with other cylinders.

(Effects of the Invention) As described above, according to the present invention, the exhaust passage of the exhaust manifold of each cylinder is branched into a first exhaust passage and a second exhaust passage, and the downstream end of the first (j1 exhaust passage) is divided into a first exhaust passage and a second exhaust passage. The second exhaust passage is connected to the turbine, and the second exhaust passage is connected to the bypass valve. Because the exhaust gas to be bypassed by the bypass valve is not passed through the entire exhaust passage up to the turbine, The exhaust passage can be narrowed without increasing passage resistance, and the responsiveness of supercharging can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a turbocharged engine according to one embodiment of the present invention, and FIG. 2 is a block diagram of a turbocharged engine according to another embodiment of the present invention. 1...Engine body, 2a, 2b, 2G, 2d, . Cylinder, 4a, 4. b, 4c, 4d...To exhaust port 1, 6a, 6b, 6c, 6cJ...Exhaust passage, 7a, 7
b. 7c, 7d=...first exhaust passage, 8a, 8b, 8c. 8 d--Second exhaust passage, 10a, 10b, 10c. 10d, 10... Bypass valve, 11... Bypass passage, 13... Turbo supercharger, 14... Turbine.

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 a turbocharged engine equipped with a bypass valve for controlling pressure, the exhaust passage is branched from the exhaust port for each cylinder into a first exhaust passage and a second exhaust passage, and the downstream end of the first exhaust passage is A turbocharged engine characterized in that the exhaust passages are assembled together and communicated with the turbine, and the second exhaust passage is communicated with the bypass valve.