JPH0345220B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an exhaust brake valve for an internal combustion engine fitted with a turbocharger.

BACKGROUND OF THE INVENTION Various types of exhaust brake valves are currently provided in turbocharged internal combustion engines to provide a means of decelerating the axle to which the engine is mounted. This is done by at least substantially closing the exhaust pipe of the engine during driving, so that the energy required to compress the air against the obstacle is used to pull the vehicle drive system back. has been converted through. An example is described in US Pat. No. 4,138,849.

SUMMARY OF THE INVENTION One drawback of such a device is that it is a twin-entry system with a separate exhaust manifold and internally each half of the separate manifold connected to a respective turbine housing inlet. When installed on an engine with a turbocharger having a turbine housing, the closure of the exhaust brake valve separates the two halves of the separated manifold into two small volume gas intakes. As a result, when one cylinder exhausts into the exhaust manifold, the exhaust manifold pressure peaks, resulting in a large effect on the exhaust manifold side of adjacent exhaust valves, which causes these valves to It becomes open state against the action of the spring. This results in the exhaust flowing back from the exhaust manifold into the cylinder on its suction stroke. This allows high pressure gas to be introduced into the cylinder through the removed exhaust valve when the piston is near the bottom of its suction stroke.
As a result, the engine further compresses this high-temperature, high-pressure gas and introduces it into the cylinder, making the cylinder high-temperature and high-pressure.

To overcome these problems, it is common to provide a gas pressure restriction means, usually by providing a leakage path for the exhaust gas through the valve closure member, thereby reducing the peak exhaust pressure in the exhaust manifold. It's a method. However, this lever method effectively reduces the average exhaust pressure within the manifold and is an effective device as a vehicle deceleration means.

The object of the invention is to provide an exhaust brake valve that eliminates the above-mentioned drawbacks.

(Means for Solving the Problems) According to the present invention, a separate exhaust manifold;
an exhaust brake valve for use with an internal combustion engine having a turbocharger having a turbine impeller in which two separate gas streams can be introduced from the separate manifolds, the valve comprising:
In a non-exhaust braking condition, free independent flow from the two gas passages is provided from the separate manifold to the turbine impeller, while in an exhaust braking condition, gas flow to the turbine impeller is cut off by a closure member of the valve; An interconnection between these two gas flow paths is provided upstream of the closure member.

The invention also provides an exhaust brake valve of the above type, wherein the valve has two halves communicating with the two halves of the divided exhaust manifold.
a hollow chamber having two inlet passageways and two outlet passageways communicating with the two inlet passageways of the turbine housing; an exhaust brake position substantially preventing gas flow from the inlet to the outlet passageway of the hollow chamber; and,
an adjustable member mounted within the venting chamber for selective adjustment between an exhaust brake position allowing free flow of gas between the inlet passageway and the outlet passageway of the hollow chamber; at least one other passageway arranged to communicate the two inlet passageways with each other, the passageway being unobstructed and open to permit gas flow between the two inlet passageways when the adjustable member is in the exhaust braking position; and at least one closed to stop the gas flow when in the non-exhaust braking position.
Consisting of two separate passages.

The present invention thus relates to an exhaust brake valve for use with an internal combustion engine having a separate exhaust manifold and a turbocharger having a turbine impeller from which two separate gas streams can be guided. The valve provides free and separate flow of two gas passages from separate manifolds to the turbine impeller in non-exhaust braking conditions, but in exhaust braking conditions gas flow to the turbine impeller is controlled by the valve's closure member 19. and an interconnection between the two gas passages is provided upstream of the closure member 19.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As best seen in FIGS. 1, 2 and 3, an embodiment of the present invention is incorporated into a housing 10 of a twin-entry turbocharger 12 having two inlets. The housing 10 has an inlet portion 14 . The inlet section 14 has a flange 16 by which the housing can be attached to the discharge side of a segmented exhaust manifold of an engine (not shown). Entrance part 1
4 has a pair of parallel inlet passages 14a, 14b, which constitute two inlet pipes to the twin-entry turbocharger. Each half of the divided manifold is connected to the turbine housing inlet 15a, 15b, respectively, and the turbine impeller 17 is appropriately supported.
It is designed to be discharged through.

Passages 14a, 14b can be selectively closed by a valve arrangement 18 to provide engine braking. In this embodiment, the valve is in the form of a rotary cylinder with a rotor 20 supported in a cylinder chamber 22 by integral shafts 34,19. The shaft 19 is supported within a boss 19a of the housing 10 by a bearing 19b. The shaft 34 extends to the outside of the housing 10 via the boss 21 and the bearing 21
It is pivotally supported by a. The rotor 20 includes a pair of laterally oriented through holes 24, 26 which, in the open state of the valve, define a continuation of the passages 14a, 14b as shown in FIG. When passing between this manifold and the turbine impeller 17, the passage 14
The gases in a, 14b are completely separated in this state of valve 18.

However, when the valve 18 is rotated approximately 90 degrees to the closed position,
As shown in FIGS. 3, 4 and 5, that location blocks the flow to the turbine housing inlets 15a, 15b and interconnects the passage sections 14a, 14b upstream of the valve closing member. The interconnection between passageway portions 14a and 14b is such that the restriction on gas flow through the connection does not increase pressure pulses within either half of the split manifold above a predetermined maximum value. The dimensions are as follows.

The desired cross-sectional area of this interconnection can be obtained by providing a single passageway formed within the valve housing or within the valve closure member or by multiple passageways formed within the valve housing or within the valve closure member. . This desirable cross-sectional area is also achieved by providing single or multiple passages within the valve housing and within the valve closure member.

As shown in FIG. 4, one interconnection is provided in the rotor 20 via a recess 28. As shown in FIG. This recess 28 extends laterally with respect to the gas flow into the passages 14a, 14b and forms a wall 44 dividing these passages.
extending across. Another interconnection is a similarly oriented recess 30 in the part of the housing 10 forming the cylindrical side wall of the cylinder chamber 22.
It is established by As best shown in FIGS. 3 and 5, this recess 30 is located in the rotor holes 24, 2.
These holes 24, 26 are arranged so as to remain partially in communication with the respective passages 14a, 14b in the positions shown in FIGS. 3 and 5. . This passage is indicated by arrow A in FIG.

Gas flow thus occurs between the two passages 14a, 14b when the valve is in the closed position, cutting off gas flow to the turbine.

Figure 6 shows 1 which can control the operation of the valve.
Two mechanisms are shown. This mechanism uses an externally mounted activation cylinder or solenoid 32 to rotate the shaft 34 of the rotor 20 approximately 90 degrees. This uses a linkage 36 and a crank arm 35 attached to the shaft 34 as disclosed in U.S. Pat. No. 4,183,849.

The embodiments described above provide a significant reduction in the peak pressure experienced in the exhaust manifold.
To illustrate this phenomenon, the curve in Figure 7 shows that the number of cylinders exhausting into the divided manifold halves is six.
Figure 2 shows exhaust manifold pressure versus crank angle for three cylinders of an engine.
Curve C, which has a high peak pressure and a low companion peak pressure, is when an exhaust brake valve is used to effectively separate the exhaust manifold into two independent sections. Curve D, which has approximately equal peak pressures, is for the case where an exhaust brake valve is used to make the connection between the two halves of the manifold as in the present invention. This curve effectively doubles the volume displaced by each cylinder, thus resulting in lower peak pressures. A similar condition occurs within each half of a split exhaust manifold for a multi-cylinder engine.

(Effects of the Invention) According to the present invention, the peak pressure can be reduced to a value lower than the pressure at which the exhaust valve opens, and at the same time the average value of the exhaust manifold pressure is increased. This results in a higher average manifold pressure being exhausted by each cylinder, effectively increasing the braking effectiveness of the vehicle's engine. At the same time, the cylinder temperature is reduced compared to the case without interconnection.

[Brief explanation of drawings]

1 is a partial sectional view of an embodiment of the exhaust brake valve according to the invention; FIG. 2 is a cross-section taken along line A-A in FIG. 1 with the valve open and the interconnecting passage closed; FIG. 3; 1 is a cross-sectional view taken along line A-A in FIG. 1, with the valve closed and the interconnecting passageway open; FIG. 4 is a cross-sectional view taken along line B-B in FIG. 3; and FIG.
6 is an external plan view showing one valve actuation mechanism, and FIG. 7 is a graph of exhaust manifold pressure versus crank angle illustrating the advantages of the present invention. Explanation of symbols, 10: Housing, 14: Inlet section, 14a, 14b: Inlet passage, 15a, 15
b: Turbine housing inlet, 19: Shaft, 20:
Rotor, 22: cylinder chamber, 24, 26: through hole, 28, 30: recess, 32: solenoid.

Claims (1)

[Scope of Claims] 1. An exhaust brake valve for use in an internal combustion engine having a segmented exhaust manifold and a turbine having a turbine impeller through which an independent gas flow can be introduced from the segmented manifold, , two inlet passages communicating with the two halves of the split exhaust manifold and two halves of the turbine housing.
means forming a cylindrical hollow part having a pair of through passages, and an inlet passage of the hollow part within the cylindrical hollow part; a first position that substantially prevents gas flow from the hollow portion to the outlet passage; and a second position that allows gas to flow between the inlet passage and the outlet passage of the hollow portion via the pair of through passages.
means defining a cylindrical rotor closure member rotatably supported for selective positioning between positions; and at least one interconnecting passageway between said inlet passageways; an exhaust brake valve comprising: means defining said interconnecting passageway means selectively operable to open when said closure member is in said first position and close when said closure member is in said second position; 2. said interconnecting passage means comprising means for forming a flow passage in at least one rotor and a hollow portion of said valve, said flow passage means connecting said inlet passages when said rotor is in a first position; 2. The exhaust brake valve of claim 1, wherein the exhaust brake valve is adapted to block flow when rotated to the second position. 3. said flow passage means comprising a recess in the wall of said hollow part of said valve, said rotor cooperating with said recess to close said recess when in a second position and to close said recess when in a first position; 3. The exhaust brake valve of claim 2, which opens to the passage. 4. The exhaust brake valve of claim 1, wherein the axis of the rotor lies perpendicular to and substantially in the plane of the longitudinal axes of the inlet and outlet passages of the valve. 5. The valve of claim 1 further comprising an actuator mounted externally on the valve and connected to the rotor for selectively rotating the rotor between a first position and a second position of the rotor. Exhaust brake valve.