GB2551160A

GB2551160A - Valve assembly

Info

Publication number: GB2551160A
Application number: GB1609997.0A
Authority: GB
Inventors: Seebooa Asveen
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2016-06-08
Filing date: 2016-06-08
Publication date: 2017-12-13
Anticipated expiration: 2036-06-08
Also published as: GB2551160B; GB201609997D0

Abstract

A valve assembly 50 for a gas flow system of an automotive internal combustion engine 1, comprising: first and second valve elements (53a, 53b, fig.3), which are movable between open and closed positions for restricting gas flow through first 8a and second 8b /flow paths. A common actuator 55 is arranged to control the position of each of the first and second valve elements. The first and second valve elements are preferably arranged to be operated out of phase with each other and may be butterfly valves mounted on a single shaft. The assembly may be part of an intake 3 or an exhaust system and/or used in conjunction with a third flow path 8c and/or electric superchargers 6, 7. A gas flow system, an intake system, and an exhaust system are also claimed.

Description

VALVE ASSEMBLY

TECHNICAL FIELD

The present disclosure relates to a valve assembly for a gas flow system and particularly, but not exclusively, to a valve assembly for a gas flow system of an automotive internal combustion engine. Aspects of the invention relate to a valve assembly, to a gas flow system, and to an internal combustion engine.

BACKGROUND

An intake or exhaust system of an automotive internal combustion engine may include two or more separate flow paths, each of which may be provided with a valve that is operable to control the flow of gases through its respective flow path. For example, an intake or exhaust system may include two (or more) alternative parallel flow paths in a selectively configurable arrangement, which may be controlled to cause gases flowing through the intake or exhaust system to flow either through a first one of the flow paths in a first configuration or alternatively through a second one of the flow paths in a second configuration.

Generally, each valve used to control the flow of gases through a flow path of an intake or exhaust system comprises a housing, a valve element located within the housing for controlling the flow of gases through its respective flow path, and an actuator for controlling the position of the valve element.

While allowing multiple flow paths of the intake or exhaust system to be controlled as desired, the use of valves adds to the cost, weight, parts-count and control complexity of the overall intake or exhaust system.

It is an aim of the present invention to address disadvantages associated with the prior art.

SUMMARY OF THE INVENTION

According to an aspect of the present invention there is provided a valve assembly for a gas flow system, comprising: first and second valve elements, wherein the first valve element is movable between an open position for allowing gas flow through a first flow path of the gas flow system and a closed position for restricting gas flow through the first flow path of the gas flow system, and wherein the second valve element is movable between an open position for allowing gas flow through a second flow path of the gas flow system and a closed position for restricting gas flow through the second flow path of the gas flow system; and a common actuator arranged to control the position of each of the first and second valve elements; wherein the first and second valve elements are arranged to be operated out of phase with each other.

The valve assembly may optionally be a valve assembly for a gas flow system of an automotive internal combustion engine.

The first and second valve elements are capable of controlling gas flow through first and second flow paths when the valve assembly is incorporated in a gas flow system including the first and second flow paths. However, it will be appreciated that the valve assembly may be provided separately to the gas flow system in which it is to be incorporated.

The valve assembly of the present invention allows a gas flow system (for example a gas flow system of an automotive internal combustion engine) in which the valve assembly may be incorporated to open a first flow path while closing a second flow path (and vice-versa) without requiring the use of two separate valves operated by two separate actuators. The present invention therefore allows a reduction in the cost, weight, parts count and control complexity of a gas flow system (for example a gas flow system of an automotive internal combustion engine). The present invention maybe used in any gas flow system of an automotive internal combustion engine in which it is desired to open at least one flow path while closing at least one other flow path.

The common actuator may be arranged to control the position of each of the first and second valve elements simultaneously using a single output to which each of the first and second valve elements is coupled.

The actuator may be a rotary actuator or alternatively a linear actuator.

The first and second valve elements may be arranged to be operated 90 degrees out of phase with each other such that when the first valve element is in its closed position the second actuator is in a position of maximum opening, and vice-versa.

The first and second valve elements may have a fixed phase relationship with each other.

The first and second valve elements may be arranged to be rotated between their respective open and closed positions.

The first and second valve elements may be butterfly valve elements. Alternatively any other form of valve element suitable for selectively restricting or preventing gas flow through a flow passage may be employed.

The first and second valve elements may be arranged along a common pivot axis about which each of the first and second valve elements is arranged to rotate between its open and closed positions. Alternatively the first and second valve elements may be arranged to pivot about separate pivot axes, which may be parallel pivot axes.

The first and second valve elements may be angularly offset from each other in order to operate out of phase with each other. For example, the first and second valve elements may be offset from each other by approximately 90 degrees about the common pivot axis (or about their respective pivot axes). Angular offsets of less than 90 degrees are also possible, for example where each of the valve elements is arranged to rotate by less than 90 degrees between its closed position and its position of maximum opening.

The first and second valve elements may be fixed to a common shaft.

The common shaft may be coupled directly to a rotary output of the actuator. Alternatively the common shaft may be coupled to a rotary or linear output of the actuator via a coupling mechanism for enabling the common actuator to rotate the common shaft. Such a coupling mechanism may include, for example, one or more gears, cranks or levers.

Alternatively the first and second valve elements may be fixed respectively to separate shafts. In this case a first one of the shafts may be coupled directly to a rotary output of the actuator, or alternatively coupled to a rotary or linear output of the actuator via a coupling mechanism. The second one of the shafts may also be coupled to the output of the actuator via a further coupling mechanism, or alternatively may be coupled to the first one of the shafts via a further coupling mechanism in order to enable the actuator to control the position of both of the first and second valve elements.

The first and second valve elements may be arranged to at least substantially prevent gas flow through their respective flow paths when in their closed positions. It may therefore be possible to substantially or alternatively completely seal either of the first and second flow paths when its respective valve element is in its closed position.

The valve assembly may further comprise a biasing system for biasing the valve assembly into a position in which one of the first and second valve elements is in its open position and the other one of the first and second valve elements is in its closed position.

The first and second flow paths may run substantially parallel to each other at the location of the valve elements.

The valve assembly may further comprise a common housing, wherein the first and second valve elements are located within and/or mounted to the common housing.

Where the first and second valve elements are fixed to a common shaft the common shaft may be rotatably mounted to the housing. Alternatively the gas flow system may comprise separate housings for the first and second valve elements.

The valve assembly may comprise first and second flow passages, wherein the first valve element is operable to control the flow of gas through the first flow passage, and wherein the second valve element is operable to control the flow of gas through the second flow passage. The first flow passage may be arranged to form part of the first flow path and the second flow passage may arranged to form part of the second flow path when the valve assembly is incorporated into a gas flow system including the first and second flow paths. The first and second flow passages may be provided by the common housing, or alternatively by separate housings. In either case the first and second flow passages may run substantially parallel to each other.

The first valve element may be arranged in the first flow passage, and the second valve element may be arranged in the second flow passage. Alternatively one or both of the first and second valve elements may be arranged outside the first and second flow passages, for example at ends of the first and second flow passages.

The valve assembly may further comprise a third valve element that is movable between an open position for allowing gas flow through a third flow path of the gas flow system and a closed position for restricting gas flow through the third flow path of the gas flow system. It will be appreciated that any features of the first and/or second valve elements described above may equally apply to the third valve element. In particular, the common actuator may additionally be arranged to control the position of the third valve element. It will further be appreciated that the valve assembly may, in some embodiments, comprise more than three valve elements.

The third valve element may be arranged to be operated out of phase with the first valve element and in phase with the second valve element. A further aspect of the present invention provides a gas flow system (for example a gas flow system of or for an automotive internal combustion engine) comprising first and second flow paths and a valve assembly as described above. The first valve element may be operable to control the flow of gas through the first flow path and the second valve element may be operable to control the flow of gas through the second flow path. However, as mentioned above, it will be appreciated that the valve assembly may be provided separately to the gas flow system in which it is to be incorporated. The first flow path may be opened while the second flow path is closed by operating the actuator to move the first valve element into (or maintain the first valve element in) its open position and to move the second valve element into (or maintain the second valve element in) its closed position, and vice-versa. The first and second flow paths may be alternative flow paths arranged in parallel with each other. The valve assembly may be operable to selectively cause gases flowing through the gas flow system to flow either via the first flow path (but not the second flow path) or via the second flow path (but not the first flow path).

Where the valve assembly comprises a third valve element, the gas flow system may further comprise a third flow path, with the third valve element being operable to control the flow of gas through the third flow path. In this case the first, second and third flow paths may each be opened or closed as required by operating the common actuator. The first, second and third flow paths may be alternative flow paths arranged in parallel with each other. The valve assembly may be operable to selectively cause gases flowing through the gas flow system to flow either via the first flow path (but not the second or third flow paths) or via the second and third flow paths (but not the first flow path).

The gas flow system may be an intake system (for example an intake system of or for an automotive internal combustion engine).

Where the intake system comprises first and second flow paths, the first flow path may be arranged to deliver air from an outlet of a first electric supercharger to an inlet of a second electric supercharger; and the second flow path may be arranged to deliver air from the outlet of the first electric supercharger and bypass the second electric supercharger, or alternatively the second flow path may be arranged to bypass the first electric supercharger and deliver air to the inlet of the second electric supercharger.

Where the intake system comprises first, second and third flow paths, the first flow path may be arranged to deliver air from an outlet of a first electric supercharger to an inlet of a second electric supercharger; the second flow path may be arranged to deliver air from the outlet of the first electric supercharger and bypass the second electric supercharger; and the third flow path may be arranged to bypass the first electric supercharger and deliver air to the inlet of the second electric supercharger.

The gas flow system may be an exhaust system (for example an exhaust system of or for an automotive internal combustion engine). In this case the first flow path may be a first exhaust gases flow path and the second flow path may be an alternative exhaust gases flow path arranged in parallel with the first exhaust gases flow path.

The valve assembly of the present invention may equally be used in any other gas flow system of an automotive internal combustion engine (besides those described above) in which it is desired to open at least one flow path while closing at least one other flow path. A further aspect of the present invention provides an internal combustion engine (for example an automotive internal combustion engine) fitted with a gas flow system as described above. A further aspect of the present invention provides a vehicle comprising an engine as described above. The vehicle may be, for example, a road vehicle such as a car or a van, or alternatively an off-road vehicle. A further aspect of the present invention provides a valve assembly for a gas flow system (for example a gas flow system of an automotive internal combustion engine), comprising: first and second flow passages arranged to allow a gas to flow therethrough; first and second valve elements, wherein the first valve element is movable between an open position in which gas flow through the first flow passage is permitted and a closed position in which gas flow through the first flow passage is restricted, and wherein the second valve element is movable between an open position in which gas flow through the second flow passage is permitted and a closed position in which gas flow through the second flow passage is restricted; and a common actuator arranged to control the position of each of the first and second valve elements;

The first and second valve elements may be are arranged to be operated out of phase with each other.

The valve assembly may generally include any of the features described above in connection with the first aspect of the present invention. A further aspect of the present invention provides a valve assembly for a gas flow system (for example a gas flow system of an automotive internal combustion engine), comprising: first and second valve elements, wherein the first valve element is movable between an open position for allowing gas flow through a first flow path of the gas flow system and a closed position for restricting gas flow through the first flow path of the gas flow system, and wherein the second valve element is movable between an open position for allowing gas flow through a second flow path of the gas flow system and a closed position for restricting gas flow through the second flow path of the gas flow system; and a common actuator arranged to control the position of each of the first and second valve elements.

The first and second valve elements may be fixed to a common shaft upon which each of the first and second valve elements is arranged to rotate between its open and closed positions.

Optionally, the first and second valve elements may be arranged to be operated out of phase with each other. However, this is not required in all embodiments, and in some embodiments the first and second valve elements may be arranged to be operated in phase with each other. In particular, where the first and second valve elements are arranged to be operated in phase with each other, the valve assembly may be comprised in an intake system of or for an automotive internal combustion engine comprising first and second flow paths, wherein the first flow path is arranged to deliver air from an outlet of a first electric supercharger and bypass a second electric supercharger, and wherein the second flow path is arranged to bypass the first electric supercharger and deliver air to an inlet of the second electric supercharger. The valve assembly may generally include any of the features described above in connection with the first aspect of the present invention.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 illustrates a car including an automotive internal combustion engine fitted with an intake system comprising a valve assembly in accordance with one possible embodiment of the present invention;

Figure 2 schematically illustrates the engine, intake system and valve assembly of the vehicle of Figure 1;

Figures 3, 4 and 5 schematically illustrate the valve assembly during different modes of operation of the intake system;

Figures 6 and 7 schematically illustrate various automotive internal combustion engines fitted with intake systems comprising valve assemblies in accordance with other possible embodiments of the present invention; and

Figure 8 schematically illustrates a portion of an exhaust system comprising a valve assembly according to another possible embodiment of the present invention.

DETAILED DESCRIPTION

Figure 1 illustrates a car 100 comprising an automotive internal combustion engine 1. The engine 1 is fitted with an exhaust system 2 for removing combustion gasses from the engine and an intake system 3 for delivering air to the engine, as schematically illustrated in Figure 2. The engine 1 may be any type of automotive engine, for example a 4-stroke engine with 4 cylinders and a displacement of approximately 2L.

The intake system 3 comprises an air filter 4 through which air enters the intake system. The intake system 3 further comprises a conventional turbocharger 5 comprising a turbine arranged to be driven by exhaust gasses flowing through the exhaust system 2 and a compressor that is driven by the turbine and that is arranged to compress air flowing through the intake system. Conventional turbochargers are well known to those skilled in the art, so the features and operation of the turbocharger 5 will not be discussed further.

The intake system 3 further comprises first and second electric superchargers 6, 7. Each of the electric superchargers 6, 7 comprises a compressor arranged to compress air flowing through the intake system 3 before delivery to the engine 1, and an electric motor arranged to drive the compressor. The electric superchargers 6, 7 are of the same model and each have an identical power rating of 5kW.

The first and second electric superchargers 6, 7 are powered by a main battery 20 of the car, and their operation is controlled by a control module 21, which may be the main ECU of the car or alternatively a separate controller. The control module 21 is arranged to operate the first and second electric superchargers 6, 7 together and to always provide the same power to each of the first and second electric superchargers 6, 7 in order to minimise the complexity of controlling the charging system.

The first and second electric superchargers 6, 7 are provided in a configurable arrangement that can be selectively switched during use of the engine 1 between a series configuration in which the two electric superchargers are arranged in series with each other, and a parallel configuration in which the two electric superchargers are arranged in parallel with each other. The series configuration is a configuration in which air flows through the first electric supercharger 6 before flowing through the second electric supercharger 7, while the parallel configuration is a configuration in which a first air stream flows through the first electric supercharger (but not the second electric supercharger) while a parallel second air stream flows through the second electric supercharger (but not the first electric supercharger). The configurable arrangement is arranged to be selectively switched between the series configuration and the parallel configuration by a valve assembly 50 according to an embodiment of the present invention, which is described in more detail below.

The first and second electric superchargers 6, 7 are both arranged in series with and downstream of the turbocharger 5, and so are each arranged to further compress air that has already been compressed by the turbocharger, although in other embodiments the first and second electric superchargers could equally be arranged in parallel with the turbocharger, or the turbocharger could be replaced by a conventional mechanical supercharger, or omitted altogether.

The first and second electric superchargers 6, 7 are arranged on opposite sides of the engine 1, although could equally be arranged on the same side of the engine.

When the first and second electric superchargers 6, 7 are in the series configuration, an outlet of the first electric supercharger is connected to an inlet of the second electric supercharger 7 by a first flow path 8a for delivering air from the first electric supercharger to the second electric supercharger.

The intake system 3 further comprises a second flow path 8b for delivering air from the outlet of the first electric supercharger 6 and bypassing the second electric supercharger 7 when the first and second electric superchargers 6, 7 are in the parallel configuration.

The intake system 3 further comprises a third flow path 8c for bypassing the first electric supercharger 6 and delivering air to the second electric supercharger 7 when the first and second electric superchargers 6, 7 are in the parallel configuration.

The first, second and third flow paths 8a, 8b, 8c all run in parallel with each other and together provide a configurable supercharged flow path.

The intake system is provided with a valve assembly 50 for selectively switching the first and second electric superchargers 6, 7 between the series and parallel configurations. The valve assembly 50 comprises a housing 51 providing first, second and third flow passages 52a, 52b, 52c, as schematically illustrated in Figures 3 and 4. The first, second and third flow passages run substantially parallel to each other. The first flow passage 52a forms part of the first flow path 8a for delivering air from the first electric supercharger 6 to the second electric supercharger 7 when the first and second electric superchargers are operated in the series configuration. The second flow passage 52b forms part of the second flow path 8b for delivering air from the first electric supercharger 6 and bypassing the second electric supercharger 7 when the first and second electric superchargers are operated in the parallel configuration. The third flow passage 52c forms part of the third flow path 8c for bypassing the first electric supercharger 6 delivering air to the second electric supercharger 7 when the first and second electric superchargers are operated in the parallel configuration.

Each of the first, second and third flow passages 52a, 52b, 52c is provided with a respective valve element 53a, 53b, 53c, for example a butterfly valve element as schematically illustrated in Figures 3 and 4. Each valve element 53a, 53b, 53c is rotatable between a closed position in which it acts to prevent the flow of air through its respective flow passage 52a, 52b, 52c (and therefore through its respective flow path 8a, 8b, 8c), and an open position in which fluid flow is enabled. Each valve element 53a, 53b, 53c may be arranged to at least substantially completely seal its respective flow passage 52a, 52b, 52c to thereby seal its reflective flow path 8a, 8b, 8c when in the closed position.

The first, second and third valve elements 53a, 53b, 53c are each arranged along a common pivot axis and fixed to a common shaft 54, as schematically illustrated in Figure 5. The common shaft 54 is rotatably mounted to the housing 51. The common shaft 54 is coupled to an output of a common actuator 55 (also shown in Figure 5) which is operable to rotate the common shaft to thereby control the position of each of the first, second and third valve elements 53a, 53b, 53c.

The second and third valve elements 53b, 53c are both offset from the first valve element 53a by approximately 90 degrees. The second and third valve elements are therefore arranged to be operated 90 degrees out of phase with the first valve element 53a such that when the first valve element 53a is in its closed position the second and third valve elements 53b, 53c are each in positions of maximum opening. The second and third valve elements 53b, 53c are not angularly offset from each other, and so are arranged to be operated in phase with each other. The first, second and third valve elements 53a, 53b, 53b have a fixed phase relationship due to each being fixed to the common shaft 54.

The common actuator 55 is operable to rotate the common shaft 54 into (or maintain the common shaft in) a first position in which the first valve element 53a is in a position of maximum opening and the second and third valve elements 53b, 53c are in their closed positions, as schematically illustrated in Figure 3. In this position the first flow path 8a is kept open while the second and third flow paths 8b, 8c remain closed, and so it is possible to operate the first and second electric superchargers 6, 7 in the series configuration. The common actuator is also operable to rotate the common shaft 54 into (or maintain the common shaft in) a second position in which the first valve element 53a is in its closed position and the second and third valve elements 53b, 53c are in their positions of maximum opening, as schematically illustrated in Figure 4. In this position the first flow path 8a is closed while the second and third flow paths 8b, 8c are opened, and so it is possible to operate the first and second electric superchargers 6, 7 in the parallel configuration.

The valve assembly 50 is further provided with a biasing element 56 for biasing the common shaft 54 towards its first position. By biasing the common shaft 54 in this direction it is possible to achieve a failsafe mode with the first valve element 53a in its open position and the second and third valve elements 53b, 53c in their closed positions, such that the configurable electric supercharger arrangement defaults to the series configuration. However, in other embodiments a biasing element could equally act to bias the common shaft in the opposite direction.

The intake system 3 further comprises a bypass line 12 that is operable to selectively bypass the supercharged flow path 8a, 8b, 8c (including the first and second electric superchargers 6, 7). The bypass line 12 is arranged in series with and downstream of the turbocharger 5, but runs in parallel with the supercharged flow path 8a, 8b, 8c and each of the first and second electric superchargers 6, 7. The bypass line 12 is provided with a bypass valve 13 which may be selectively opened to allow air flowing through the intake system 3 to bypass the first and second electric superchargers 6, 7, and closed to shut the bypass line 12 such that air flowing through the intake system flows via the supercharged flow path 8a, 8b, 8c and through the first and second electric superchargers 6, 7.

The intake system further comprises a charge cooling device 9, a throttle device 10 and an intake manifold 11 arranged in series with and downstream of each of the turbocharger 5 and the first and second electric superchargers 6, 7.

Operation of the intake system 3 and the valve assembly 50 will now be described.

During normal steady state operation of the engine 1, the bypass valve 13 is maintained in its open position. In this state, air being delivered to the engine 1 by the intake system 3 is compressed by the turbocharger 5, and then flows through the bypass line 12, thereby bypassing the supercharged flow path 8a, 8b, 8c and the first and second electric superchargers 6, 7. The compressed air is then cooled by the charge cooling device 9 before passing through the throttle device 10 and entering the engine 1 via the intake manifold 11.

When the throttle position is increased, the first and second electric superchargers 6, 7 may be operated in order to further compress the air being delivered to the engine 1 by the intake system 3 to provide a more rapid response to the increased throttle position and combat turbo lag. The ECU of the vehicle determines which configuration should be used. This determination may be based on, for example, the throttle position and/or the engine speed or air mass flow rate. For example, the series configuration may be selected when a large increase in the throttle angle is detected and/or when the engine speed is low, and the parallel configuration may be selected at higher engine speeds.

If it is determined that the first and second electric superchargers 6, 7 should be operated in the series configuration, the common actuator 55 is operated to move the common shaft 54 into (or maintain the common shaft in) its first position, such that the first flow path 8a is open while the second and third flow paths 8b, 8c remain closed. In this configuration, the first and second electric superchargers 6, 7 are operated together in series with each other to sequentially further compress air flowing through the intake system 3 via the first flow path 8a.

Alternatively, if it is determined that the first and second electric superchargers 6, 7 should be operated in the parallel configuration, the common actuator 55 is operated to move the common shaft 54 into (or maintain the common shaft in) its second position, such that the first flow path 8a is closed while the second and third flow paths 8b, 8c are opened. In this configuration, the first and second electric superchargers 6, 7 are operated together in parallel and each compress a portion of the air flowing through the intake system 3 via the second and third flow paths 8b, 8c.

When the engine 1 returns to steady state operation the first and second electric superchargers 6, 7 may be deactivated and the bypass valve 13 may be opened to reopen the bypass line 12, thereby allowing air flowing through the intake system 3 to bypass the supercharged flow path 8a, 8b, 8c and the first and second electric superchargers 6, 7.

The configurable arrangement described above allows the most advantageous configuration of the two electric superchargers 6, 7 to be selected for any given operating condition of the engine 1 such that the overall performance of the charging system may be optimised over a wider range of operating conditions.

The use of a common valve assembly 50 to control the opening and closing of the first, second and third flow paths 8a, 8b, 8c allows a reduction in the cost, weight, parts count and control complexity compared to an alternative solution in which three separate valves controlled by three separate actuators are used to open and close the first, second and third flow paths 8a, 8b, 8c.

In the above described embodiment, the valve assembly 50 comprises three valve elements 53a, 53b, 53c arranged to open and close three different flow paths 8a, 8b, 8c arranged in parallel with each other in a gas flow system. However, in other embodiments, a valve assembly may comprise only two valve elements arranged to open and close two different flow paths. For example, Figures 6 and 7 illustrates two alternative embodiments that are generally similar in structure and operation to the embodiment of Figure 2. Features already described in relation to the embodiment of Figure 2 are given numbers in the 100 and 200 series respectively, and only differences compared to the embodiment of Figure 2 will be described.

In the embodiment of Figure 6, the valve assembly 150 comprises only two flow passages, respectively forming part of a first flow path 108a for delivering air from the outlet of the first electric supercharger 106 to the inlet of the second electric supercharger 107 and a second flow path 108c for bypassing the first electric supercharger 106 and delivering air to the inlet of the second electric supercharger 107. In this embodiment, first and second valve elements 153a, 153c of the valve assembly 150 are fixed to a common shaft 154 and arranged to be controlled by a common actuator 155 to open and close the first and second flow paths 108a, 108c. The valve elements 153a, 153c are arranged to be operated out of phase with each other. A separate valve 153b controlled by a separate actuator is used to open and close a further flow path 108b for delivering air from the first electric supercharger 106 and bypassing the second electric supercharger 107.

It will be appreciated that in another embodiment a similar valve assembly could equally be arranged to control the flow path 108a for delivering air from the outlet of the first electric supercharger 106 to the inlet of the second electric supercharger 107 and the flow path for 108b for delivering air from the first electric supercharger 106 and bypassing the second electric supercharger 107. In such an embodiment the flow paths 108a, 108b may be regarded as first and second flow paths within the meaning of the accompanying claims.

In the embodiment of Figure 7, the valve assembly 250 comprises only two flow passages, respectively forming part of a first flow path 208b for delivering air from the first electric supercharger 206 and bypassing the second electric supercharger 207 and a second flow path 208c for bypassing the first electric supercharger 206 and delivering air to the inlet of the second electric supercharger 207. In this embodiment, first and second valve elements 253b, 253c of the valve assembly 250 are fixed to a common shaft 254 and are arranged to be controlled by a common actuator 255 to open and close the first and second flow paths 208b, 208c. The valve elements 253b, 253c are arranged to be operated in phase with each other. A separate valve 253a controlled by a separate actuator is used to open and close a further flow path 208a for delivering air from the outlet of the first electric supercharger 206 to the inlet of the second electric supercharger 207.

It will be appreciated that a valve assembly according to the present invention may also be used in other inlet and exhaust systems where is it desired to open and close multiple gas flow paths. For example, Figure 8 schematically illustrates a portion of an exhaust system 301 that splits into a first exhaust gases flow path 302 and an alternative exhaust gases flow path 303 arranged in parallel with the first exhaust gases flow path. The exhaust system 301 is provided with a valve assembly 304 comprising first and second flow passages respectively forming part of the first exhaust gases flow path 302 and the alternative exhaust gases flow path 303. The valve assembly 304 further comprises first and second valve elements 305, 306 each arranged to open and close a respective one of the first exhaust gases flow path 302 and the alternative exhaust gases flow path 303. The first and second valve elements 305, 306 are fixed to a common shaft 308 and are arranged to be operated out of phase with each other such that when the first valve element 305 is in its open position the second valve element 306 is in its closed position, and vice versa. The valve assembly 304 comprises a common actuator 307 for controlling the position of each of the first and second valve elements 305, 306. By operating the common actuator 307 it is possible selectively open either one of the first exhaust gases flow path 302 and the alternative exhaust gases flow path 303 while closing the other one of the first exhaust gases flow path 302 and the alternative exhaust gases flow path 303 to thereby control the route taken by exhaust gases passing through the exhaust system 301.

Many modifications may be made to the above examples without departing from the scope of the present invention as defined in the accompanying claims.

Claims

1. A valve assembly for a gas flow system of an automotive internal combustion engine, comprising: first and second valve elements, wherein the first valve element is movable between an open position for allowing gas flow through a first flow path of the gas flow system and a closed position for restricting gas flow through the first flow path of the gas flow system, and wherein the second valve element is movable between an open position for allowing gas flow through a second flow path of the gas flow system and a closed position for restricting gas flow through the second flow path of the gas flow system; and a common actuator arranged to control the position of each of the first and second valve elements; wherein the first and second valve elements are arranged to be operated out of phase with each other.

2. A valve assembly according to claim 1, wherein the first and second valve elements are arranged to be rotated between their respective open and closed positions.

3. A valve assembly according to claim 2, wherein the first and second valve elements are butterfly valve elements.

4. A valve assembly according to any preceding claim, wherein the first and second valve elements are arranged along a common pivot axis about which each of the first and second valve elements is arranged to rotate between its open and closed positions.

5. A valve assembly according to claim 4, wherein the first and second valve elements are fixed to a common shaft.

6. A valve assembly according to claim 5, wherein the common shaft is coupled directly to a rotary output of the actuator.

7. A valve assembly according to any preceding claim, further comprising a biasing system for biasing the valve assembly into a position in which one of the first and second valve elements is in its open position and the other one of the first and second valve elements is in its closed position.

8. A valve assembly according to any preceding claim, wherein the first and second flow paths run substantially parallel to each other at the location of the valve elements.

9. A valve assembly according to any preceding claim, further comprising a common housing, wherein the first and second valve elements are located within and/or mounted to the common housing.

10. A valve assembly according to any preceding claim, wherein the valve assembly comprises first and second flow passages, wherein the first valve element is operable to control the flow of gas through the first flow passage, and wherein the second valve element is operable to control the flow of gas through the second flow passage.

11. A valve assembly according to claim 10, wherein the first valve element is arranged in the first flow passage and the second valve element is arranged in the second flow passage.

12. A valve assembly according to any preceding claim, further comprising a third valve element that is movable between an open position for allowing gas flow through a third flow path of the gas flow system and a closed position for restricting gas flow through the third flow path of the gas flow system.

13. A valve assembly according to claim 12, wherein the third valve element is arranged to be operated out of phase with the first valve element and in phase with the second valve element.

14. A gas flow system of or for an automotive internal combustion engine comprising first and second flow paths and a valve assembly according to any preceding claim, wherein the first valve element is operable to control the flow of gas through the first flow path and the second valve element is operable to control the flow of gas through the second flow path.

15. A gas flow system according to claim 14 when dependent on claim 12 or claim 13, wherein the gas flow system further comprises a third flow path, wherein the third valve element is operable to control the flow of gas through the third flow path.

16. A gas flow system according to claim 14 or claim 15, wherein the gas flow system is an intake system.

17. An intake system according to claim 16 when dependent on claim 14; wherein the first flow path is arranged to deliver air from an outlet of a first electric supercharger to an inlet of a second electric supercharger; and wherein the second flow path is arranged to deliver air from the outlet of the first electric supercharger and bypass the second electric supercharger, or wherein the second flow path is arranged to bypass the first electric supercharger and deliver air to the inlet of the second electric supercharger.

18. An intake system according to claim 16 when dependent on claim 15; wherein the first flow path is arranged to deliver air from an outlet of a first electric supercharger to an inlet of a second electric supercharger; wherein the second flow path is arranged to deliver air from the outlet of the first electric supercharger and bypass the second electric supercharger; and wherein the third flow path is arranged to bypass the first electric supercharger and deliver air to the inlet of the second electric supercharger.

19. A gas flow system according to claim 14 or claim 15, wherein the gas flow system is an exhaust system.

20. An exhaust system according to claim 19, wherein the first flow path is a first exhaust gases flow path and the second flow path is an alternative exhaust gases flow path arranged in parallel with the first exhaust gases flow path.

21. An automotive internal combustion engine comprising a gas flow system according to any of claims 14 to 20.

22. A vehicle comprising an automotive internal combustion engine according to claim 21.

23. A valve assembly for a gas flow system of an automotive internal combustion engine, comprising: first and second valve elements, wherein the first valve element is movable between an open position for allowing gas flow through a first flow path of the gas flow system and a closed position for restricting gas flow through the first flow path of the gas flow system, and wherein the second valve element is movable between an open position for allowing gas flow through a second flow path of the gas flow system and a closed position for restricting gas flow through the second flow path of the gas flow system; and a common actuator arranged to control the position of each of the first and second valve elements.

24. A valve assembly according to claim 23, wherein the first and second valve elements are fixed to a common shaft upon which each of the first and second valve elements is arranged to rotate between its open and closed positions.

25. A valve assembly according to claim 24, wherein the first and second valve elements are arranged to be operated in phase with each other.

26. An intake system of or for an automotive internal combustion engine, the intake system comprising first and second flow paths and a valve assembly according to claim 25, wherein the first flow path is arranged to deliver air from an outlet of a first electric supercharger and bypass a second electric supercharger, and wherein the second flow path is arranged to bypass the first electric supercharger and deliver air to an inlet of the second electric supercharger.

27. A valve assembly, a gas flow system, an internal combustion engine or a vehicle substantially as described herein with reference to any of the detailed embodiments.