WO2003033950A1

WO2003033950A1 - Valve and motor arrangement

Info

Publication number: WO2003033950A1
Application number: PCT/SE2002/001872
Authority: WO
Inventors: Emil Kylberg; Henrik Nordin
Original assignee: Saab Automobile Ab
Priority date: 2001-10-19
Filing date: 2002-10-15
Publication date: 2003-04-24
Also published as: SE0103492D0; SE0103492L; SE520219C2

Abstract

A valve (12) having a valve housing in which a valve element (23) is moveable in relation to a valve seat (31) in order to control the flow through the valve. The valve seat is arranged in an inclined plane (32), which forms an acute angle (α) with a plane (33) perpendicular to the direction of flow (25) through the valve, and the valve element is moveable essentially in a plane perpendicular to the direction of flow through the valve and is designed, on closing of the valve, to meet an upward sloping valve seat (31). The valve element (23) is arranged upstream of the valve seat (31). This means that only small operating forces are required to move the valve from the closed position. The invention also relates to an engine arrangement having turbocharger compressors in which a valve of this type is used between the turbocharger compressors.

Description

Valve and motor arrangement

Technical area

The present invention relates partly to a valve according to the preamble to claim 1, and partly to an engine arrangement according to the preamble to claim 8.

Description of the prior art

In turbocharged internal combustion engines for vehicles, that is to say supercharged engines, in which supercharging is used at high power output, there is often a problem in obtaining sufficient power at low revolutions in order that the engine will be perceived as easy to drive. This stems from the fact that a high power output requires a high charging pressure, which in turn requires a large turbocharger unit for high engine speeds. A large turbocharger unit, however, means that the charging pressure and hence the engine torque is unacceptably low at low engine speeds. Against this background the facility for increasing the charging pressure at low engine speeds has been found to be desirable.

A common solution in this context is to use a directly- driven supercharger for the rapid attainment of a high charging pressure. A disadvantage, however, is that such a supercharger robs the engine of power and is usually noisy. The problem can also be solved by means of turbocharging (exhaust-driven turbocharger unit) , but it must then be possible to vary the size of the turbocharger depending on the engine speed and load. One possibility here is to use a turbocharger having a variable geometry, in which the inlet to the turbine can be varied, but a large turbine is still required, which at low engine speeds is not efficient and responsive enough. The constant geometry on the supercharger side also means that such a system is limited in terms of the large charge-air flow that is needed at full power. Solutions also exist in which the angle of the guide blade rims is adjustable in order to obtain a variable geometry. Such solutions, however, are fraught with sealing problems and among other things take up a lot of space and are difficult to implement in passenger cars.

According to another type of solution, use is instead made of interacting turbochargers, especially in the case of larger diesel engines. Such systems are usually constructed so that the exhaust gases first pass to a small turbocharger and then to a larger turbocharger. The small turbocharger can be bypassed by a bypass valve, so .that only the larger turbocharger is used at higher engine speeds and loads, in order to be able to obtain a higher charging pressure at low engine speeds .

The facility for also using a similar solution in passenger cars is desirable, but one problem in this context is the design of the bypass valve, which must be capable of efficient sealing in the closed position, but still be capable of easy and rapid actuation, in order to adjust to different driving situations and thereby make the engine easy to drive. Solutions hitherto proposed are fraught with inherent disadvantages.

Object of the invention

The object of the invention is to provide an improved valve of the type specified in order to make a vehicle engine easy to drive under different loads and at different engine speeds. Another object is to provide a simple and efficient valve that is easy and inexpensive to manufacture. Yet another object is that the valve should permit ease of assembly and use and be reliable in operation.

Summary of the invention

The object of the invention is achieved partly by designing a valve according to claim 1 and partly by using such a valve in an engine system according to claim 8.

By using a laterally moveable valve element, which is intended, in the closed position, to rest against an inclined valve seat, good sealing is readily achieved by allowing the exhaust gas pressure to press the valve element against its seat. The inclined position of the valve seat means that little force is required to displace the valve seat sideways in order to open the valve, which means that the valve is easily operated. The small force needed for operation means, for example, that a simple, pneumatically actuated pressure bell can be used of the same type as is commonly used for the wastegate valve in turbochargers .

The size of the exhaust gas flow that is made to bypass the first, small turbocharger compressor can easily be adjusted by moving the valve element a suitable distance sideways from its closed position.

Another advantage is that the valve element can be displaced laterally right out of the exhaust gas flow so that it has no inhibiting action on the exhaust gas flow. Furthermore, the valve element can thereby to a certain extent be shielded from hot exhaust gases. The valve, owing to the design and location of the valve element, can be made relatively short, which is advantageous from the point of view of available space. Further characteristics and advantages of a solution according to the invention are set forth in the description and other patent claims.

The invention will be described in more detail below with reference to an exemplary embodiment shown in the drawings attached.

Description of the drawings

In the drawing:

Fig . 1 shows a turbocharged internal combustion engine having a valve according to the invention,

Fig . 2 shows an exploded sketch drawing of a valve according to the invention,

Fig . 3 shows a perspective view of a valve housing part with a valve element, FFiigg.. 44 shows a perspective view of a valve housing part,

Fig . 5 shows a section V-V in Figure 4, and

Fig . 6 shows a partial section similar to Figure 5, with valve element and operating mechanism.

Description of exemplary embodiments

Figure 1 shows an engine arrangement 1, in which an internal combustion engine 2, by means of its exhaust gases, drives two turbocharger compressors 3 and 4 of different sizes arranged in series for delivering air at excess pressure to the engine 2. The turbocharger compressor 3, which is arranged closest to the engine 2, is smaller than the turbocharger compressor 4. Exhaust gases are led via an exhaust manifold 5 and a line 6 to a turbine 7 in the turbocharger compressor 3 and thence via a line 8 to a turbine 9 in the turbocharger compressor 4, and finally via a line 10 into the engine exhaust system. The lines 6 and 8 are connected to a bypass line 11, in which there is a valve 12 designed according to the invention, which will be described in more detail below.

Air is fed to the engine 2 via the two turbocharger compressors 3 and 4, air being first delivered via a line 13 to a compressor 14 in the turbocharger compressor 4 and thence via a line 15 to a compressor 16 in the turbocharger compressor 3, before finally being delivered via a line 17 and an inlet pipe 18 to the engine 2. The lines 15 and 17 are connected by a bypass line 19, in which there is a valve 20.

At low load and low speed of the engine 2, the valves 12 and 20 are closed, so that the turbine 7 in the turbocharger compressor 3 receives all exhaust gases from the engine 2 and drives the compressor 16, which feeds air at excess pressure into the engine 2. The turbocharger compressor 4 is in this case driven only very slowly by the small quantity of exhaust gases delivered thereto and therefore gives rise only to a slight compression of the air that is delivered to the engine. As the load and speed of the engine 2 increase, the flow of exhaust gas from the engine increases, and by increasingly opening the valve 12 it is possible to feed an ever greater quantity of exhaust gases directly to the turbine 9 in the turbocharger compressor 4 , with the result that the compressor 14 delivers more and more compressed air. At full load and moderately high revolutions of the engine 2, the valve 12 is only partially open, but at full load and high revolutions the valve 12 is fully open, the turbocharger compressor 4 in principle delivering all air to the engine 2. The degree of opening of the valve 12 thus depends on the current speed and load of the engine 2. In order to avoid pressure losses in the compressor 16 in the turbocharger compressor 3, when the valve 12 is fully open with a large exhaust gas flow from the engine so that the exhaust gases are consequently made to bypass the turbine 7, the valve 20 in the bypass line 19 is opened so as to permit bypassing of the compressor 16.

As has been outlined, it is possible with the turbocharger compressors 3 and 4 connected in series to use the valve 12 to control the quantity of exhaust gases that are made to bypass the turbocharger compressor 3, from a position in which the valve 12 is fully closed at low load and low engine speed to a position in which the valve 12 is fully open at high load and high engine speed. It is desirable here that the valve 12 be easy to operate and in particular that it should be easy to open.

An exemplary embodiment of a valve 12 designed according to the invention is shown in greater detail in Figures 2 to 6. As will be seen from the exploded sketch drawing in Figure 2, the valve housing for a valve 12 is made up of a lower housing part 21 and an upper housing part 22, which are designed to be joined together by means of a screwed connection, for example. A valve element 23, which is suitably disk-shaped, is situated in the valve housing and is intended, when operated by means of an operating mechanism 24, to control a flow through the valve in the direction of the arrows 25. The valve 12 is designed for fitting into a line, in this case the line 11, for example by means of conventional flanges connected on the two housing parts 21 and 22. The operating mechanism 24 is arranged in the lower valve housing part 21 in order to permit lateral movement of the valve element 23 in a recess 26 between an open and a closed valve position. The valve element 23 is fitted on an arm 27, which is in turn rotatably mounted on a crank 28, which by way of a bushing 29 is pivotally supported in the lower housing part 21. The valve element 23 can thereby be swiveled about an axis essentially parallel to the direction of flow through the valve (according to the arrows 25) .

In the lower housing part 21 there is an outlet port 30, around which there is, in the recess 26, a valve seat 31 intended for the valve element 23. By means of the operating mechanism 24, the valve element 23 can be swiveled laterally from an open valve position shown in Figure 3, entirely to the side of the outlet port 30, into a closed valve position shown in Figure 6, in which it bears against the valve seat 31 and can be pressed against this by the pressure of exhaust gases from the engine. The valve element 23 can also be set to positions between these two limit positions in order to expose or block a desired proportion of the outlet port 30.

As will be seen from Figures 3 to 6, the valve seat 31 is arranged with a certain inclination in the lower housing part 21. This inclination is intended to facilitate operation of the valve element from the closed position. According to Figure 6 the valve element 23 lies in a plane 32 which forms an acute angle α with a plane 33 perpendicular to the direction of flow (arrows 25) through the valve. The inclination of the plane 32 is such that the valve element 23, en route to the closed position, meets an upward sloping valve seat 31 and en route to the open position leaves a downward sloping valve seat 31, when swiveled circularly by means of the operating mechanism 24. In the closed position the pressure of the exhaust gases, as stated, presses the valve element 23 against the valve seat 31. In order to open the valve, with the specified solution according to the invention only a slight force is required in order to move the valve element 23 somewhat sideways, so that it loses contact with the valve seat 31. The valve element 23 can then easily be moved the required distance sideways .

In the embodiment shown here, the valve element 23 is designed to perform a swiveling movement into and from a closed position, but it is naturally possible to design the valve in some other way, for example so that the valve element 23 assumes a linear movement in the valve housing.

The size of the acute angle α may suitably be up to 20° and may advantageously be approximately 10°. The valve element 23 may suitably be rotatably mounted on the arm 27, so that the valve element can be allowed to assume different rotational positions in relation to the valve seat 31, thereby ensuring a lastingly effective seal in the valve. For operation of the operating mechanism 24 there is, according to Figures 2 and 6, an operating device 34, which may advantageously consist of a pressure bell, which is driven by means of the charge-air from the turbocharger compressors 3 and 4 and is of the conventional type commonly used to actuate the wastegate valve in turbocharger compressors. Other types of drive device, of electrical type, for example, are obviously also feasible in order to allow the valve element 23 to be set to the desired position. Together, however, the valve and the operating device should have a compact design in order to minimize the overall space required.

The valve 20 fitted in the line 19 on the air supply side may suitably be of the type in which a rotatable throttle in the closed position can block the line 19, but other designs are possible according to needs and requirements. In order to achieve a balancing of the exhaust gas flow between the two turbocharger compressors 3 and 4 corresponding to the desired engine power output in each operating situation of the engine 2, it is necessary that the operation of the two valves 12 and 20 be rapidly and efficiently controlled. The operating device 34 is therefore suitably coupled to the engine control system and is controlled thereby.

An engine arrangement 1 of the type shown in Figure 1 is particularly advantageous when the engine 2 is of the variable compression type. The facility for rapid and easy adjustment of the engine supercharging by means of a valve according to the invention allows the supercharging to be efficiently adjusted to the particular engine compression selected, thereby exploiting the advantages, afforded by adjustment of the engine compression to different operating situations.

Claims

1. A valve having a valve housing in which a valve element (23) is moveable in relation to a valve seat (31) in order to control the flow through the valve, characterized in that the valve seat (31) is arranged in an inclined plane (32) , which forms an acute angle (α) with a plane (33) perpendicular to the direction of flow through the valve, that the valve element (23) is moveable essentially in a plane (33) perpendicular to the direction of flow through the valve and is designed, on closing of the valve, to meet an upward sloping valve seat (31), and that the valve element is arranged upstream of the valve seat.

2. The valve as claimed in claim 1, characterized in that the valve element (23) is moveable to a position to the side of the valve seat (31) .

The valve as claimed in claim 1 or 2 , characterized in that the valve element (23) is capable of swiveling about an axis essentially parallel to the direction of flow through the valve.

4. The valve as claimed in any of claims 1 to 3 , characterized in that the valve element (23) is connected by an operating mechanism (24) to an operating device (34) arranged outside the valve housing.

5. The valve as claimed in claim 4, characterized in that the operating device (34) is pneumatically driven . The valve as claimed in any of claims 1 to 5, characterized in that the valve element (23) is rotatably supported in the operating mechanism (24) so as to be able to adjust the position in relation to the valve seat (31) .

The valve as claimed in any of claims 1 to 6, characterized in that the valve element (23) is disk-shaped.

An engine arrangement in which an internal combustion engine (2) by means of its exhaust gases drives two turbocharger compressors (3, 4) of different sizes arranged in series for delivering air at excess pressure to the engine, the smaller turbocharger compressor (3) being arranged closest to the engine, and a bypass line (11) , provided with a valve (12) , being provided between the inlet and outlet of the turbine (7) in the smaller turbocharger compressor (3) for bypassing the turbine in the smaller turbocharger compressor, characterized in that the valve (12) in the bypass line (11) is designed according to any of claims 1 to 7.

The engine arrangement as claimed in claim 8, characterized in that the degree of opening of the valve (12) is adjustable as a function of the engine speed and load, the valve being designed to be closed at low engine speed and low load and open at high engine speed and high load.

The engine arrangement as claimed in claim 8 or 9, characterized in that the engine (2) is designed with variable compression.