Internal combustion engine intake system and valve assembly

Abstract

Intake system (403, 503, 1003) for supplying air to an internal combustion engine of an automobile, wherein the intake system (403, 503, 1003) comprises two electric superchargers (406, 407) arranged to compress air flowing through the intake system (403, 503, 1003) prior to supplying it to the internal combustion engine during use, wherein the electric superchargers (406, 407) are charging devices in which the compressor is driven only by an electric motor, wherein the two electric superchargers (406, 407) are provided in a configurable arrangement which, during the use of the intake system (403, 503, 1003), can be selectively switched between a series configuration in which the two electric superchargers (406, 407) are arranged in series with each other and a parallel configuration in which the two electric superchargers (406, 407) are arranged in parallel with each other, wherein the intake system (403, 503, 1003) further includes an additional charging device.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to intake systems for internal combustion engines of an automobile. Inventive aspects relate to an intake system for delivering air to an internal combustion engine of an automobile and a method for operating an intake system of an internal combustion engine of an automobile.

[0002] The present disclosure also relates to a valve assembly for a gas flow system, and in particular, but not exclusively, to a valve assembly for a gas flow system of an internal combustion engine of an automobile. Aspects of the invention relate to a valve assembly, a gas flow system, and an internal combustion engine. BACKGROUND

[0003] There is currently a trend in the automotive industry toward the use of smaller-capacity engines, primarily due to fuel efficiency. To compensate for the reduced power resulting from selecting a smaller capacity engine, it is common practice to equip an engine with a supercharging system to increase the density of the air supplied to the engine, thereby increasing the torque and power available from the engine.

[0004] Conventional charging systems often include a supercharger (comprising a compressor driven by the engine via a belt, gear, shaft, or other mechanical device) and / or a turbocharger (comprising a compressor driven by an exhaust-driven turbine). A turbocharger generally provides increased torque and power with high efficiency, but experiences turbo lag because the turbine and compressor need time to ramp up after an increase in throttle position. In contrast, a supercharger generally provides a quick response to an increased throttle position but is less efficient than a turbocharger. The disadvantages of each compressor type can be offset to some extent by employing both a turbocharger and a supercharger in a single charging system, commonly known as a dual-charging system.

[0005] It is possible to equip a turbocharger with an electric motor, which can be used to assist in ramping up the compressor. Turbochargers that incorporate an electric motor to ramp up the compressor are known as electric turbochargers. Electric turbochargers can provide a faster response to increased throttle position than regular turbochargers due to the electric motor's ability to ramp up the compressor. However, these systems are relatively complex and not common in automotive applications.

[0006] A more recent concept in automotive engine charging is the use of electric superchargers. Electric superchargers are charging devices that use an electric motor to drive a compressor. In an electric supercharger, the compressor is driven solely by the electric motor. (Electric superchargers differ from electric turbochargers, in which the compressor is arranged to be driven by an exhaust-driven turbine in addition to being driven by an electric motor.) Electric superchargers can be used to rapidly increase the density of the air delivered to the engine in response to increased throttle position. However, the use of electric superchargers in automotive applications is still relatively uncommon, and electric superchargers have not yet been able to address all of the drawbacks associated with conventional charging systems.

[0007] An intake or exhaust system for an internal combustion engine of an automobile may include two or more separate flow paths, each of which is provided with a valve operable to control the flow of gases through its corresponding flow path. For example, an intake or exhaust system may include two (or more) alternative parallel flow paths in a selectively configurable arrangement that can be controlled to cause gases flowing through the intake or exhaust system to flow either through a first of the flow paths in a first configuration or alternatively through a second of the flow paths in a second configuration.

[0008] In general, any valve used to control the flow of gases through a flow path of an intake or exhaust system includes a housing, a valve element disposed within the housing for controlling the flow of gases through its corresponding flow path, and an actuator for controlling the position of the valve element.

[0009] For further background information, please refer to the publications JP H05-5419 A, US 9 010 114 B2, as well as to the Handbook of Combustion Engines, 7th edition, Wiesbaden: Springer, 2015, pp. 544 - 547, ISBN 978-3-658-04678-1 (eBook) by van Basshuysen, Richard; Schäfer, Fred (eds.).

[0010] While controlling multiple flow paths of the intake or exhaust system as desired, the use of valves adds to the cost, weight, number of parts, and control complexity of the entire intake or exhaust system.

[0011] The present invention aims to overcome the disadvantages associated with the prior art. SUMMARY OF THE INVENTION

[0012] The present subject matter is defined by the claims.

[0013] According to one aspect of the present invention, an intake system for delivering air to an internal combustion engine of an automobile is provided, the intake system comprising two electric superchargers arranged to compress air flowing through the intake system prior to delivery to the internal combustion engine in use. By providing the intake system with two electric superchargers, it is possible to increase the torque and power available from an engine of a given displacement and to provide a rapid response to an increased throttle position with high efficiency.

[0014] By deploying two electric superchargers, it is possible to maximize the beneficial effects of the electric superchargers and provide a highly optimized charging system. Furthermore, using two electric superchargers instead of a single, higher-powered electric supercharger allows for the selection of electric superchargers from a wider range of available models; it allows for greater flexibility in charging system design and operation, reduces response times due to lower inertia in each electric supercharger, and reduces the overall cost and weight of the charging system.

[0015] The intake system further includes an additional charging device. The additional charging device can be, for example, a supercharger or a turbocharger. When used in combination with an additional charging device, the two electric superchargers can help offset some of the disadvantages associated with the additional charging device. For example, when used in combination with a turbocharger, in particular, the two electric superchargers can serve to reduce lag and provide a faster response to increased throttle position, especially at low engine speeds.

[0016] The two electric superchargers may be arranged in series with (and preferably downstream of) the additional charging device or alternatively in parallel with the additional charging device.

[0017] The two electric superchargers can be arranged in series. When the two electric superchargers are arranged in series, air flows through a first electric supercharger and is compressed by it before flowing through a second electric supercharger and being further compressed by it. Arranging the two electric superchargers in series provides maximized boost pressure at low engine speeds, allowing for faster response to increased throttle position and faster acceleration.

[0018] Alternatively, the two electric superchargers can be arranged in parallel. When the two electric superchargers are arranged in parallel, a portion of the air flowing through the intake system passes through a first of the electric superchargers (but not a second of the electric superchargers) and is compressed by it, while another portion of the air flowing through the intake system passes through the second of the electric superchargers (but not the first of the electric superchargers) and is compressed by it. Arranging the two electric superchargers in parallel allows a higher maximum air mass flow rate to be achieved through the two electric superchargers, thereby expanding the engine speed range over which the two electric superchargers are effective at compressing air for delivery to an engine.

[0019] The two electric superchargers are provided in a configurable arrangement that can be selectively switched between an in-line configuration, in which the two electric superchargers are arranged in series, and a parallel configuration, in which the two electric superchargers are arranged in parallel, during intake system use. By providing such a configurable arrangement, it is possible to selectively achieve the advantages of both the in-line and parallel arrangements, allowing engine performance to be more fully optimized over a wider range of operating conditions (particularly during transient operating modes).

[0020] The intake system may include a first flow path for delivering air from an outlet of a first of the two electric superchargers to an inlet of a second of the two electric superchargers when the two electric superchargers are operated in the series configuration, a second flow path for delivering air from the outlet of the first electric supercharger and bypassing the second electric supercharger when the two electric superchargers are operated in the parallel configuration, and a third flow path for bypassing the first electric supercharger and delivering air to the inlet of the second electric supercharger when the two electric superchargers are operated in the parallel configuration.

[0021] The first flow path may be provided with a first valve element that can be opened to allow air to flow from the first electric supercharger to the second electric supercharger; the second flow path may be provided with a second valve element that can be opened to allow air to flow from the first electric supercharger and bypass the second electric supercharger; and the third flow path may be provided with a third valve element that can be opened to allow air to bypass the first electric supercharger and flow to the second electric supercharger.

[0022] The second and third valve elements may be arranged to operate in phase with each other, and the first valve element may be arranged to operate out of phase with the second and third valve elements.

[0023] Two or more of the first, second and third valve elements may be arranged to be operated together by a common actuator.

[0024] Two or more of the first, second and third valve elements may be coupled to a common shaft.

[0025] Two or more of the first, second and third valve elements may be provided within a common housing.

[0026] The intake system may further include a common charge cooling device located downstream of both electric superchargers to cool air that has flowed through one or both of the two electric superchargers. Alternatively, separate parallel charge cooling devices may be provided, with each charge cooling device located to cool air that has flowed through a corresponding one of the two electric superchargers. The charge cooling device(s) may be, for example, water-cooled air coolers.

[0027] The intake system may further include a bypass line operable to selectively bypass at least one of the two electric superchargers. The bypass line may be provided with a valve that can be opened to selectively bypass the electric supercharger(s). The intake system may include a first bypass line operable to selectively bypass a first of the two electric superchargers and a second bypass line operable to selectively bypass a second of the two electric superchargers.

[0028] The bypass line can be operated to selectively bypass both of the two electric superchargers.

[0029] The two electric superchargers may be placed within the intake system to be placed on opposite sides of an engine in which the intake system may be mounted.

[0030] The intake system may further comprise a throttle device, wherein the two electric superchargers are both arranged upstream of the throttle device.

[0031] The two electric superchargers can have the same power rating. The two electric superchargers can be the same model. Alternatively, the two electric superchargers can be different models, in which case they can have different power ratings and / or other different operating characteristics.

[0032] At least one of the two electric superchargers can have a connected load of at least 2 kW, preferably at least 3 kW, and most preferably at least 5 kW. Other connected loads are also possible, for example, 10 kW or higher.

[0033] The two electric superchargers may be arranged to be powered by a main battery of a vehicle in which the intake system is installed, or by one or more separate batteries or capacitors. The one or more separate batteries or capacitors may be included in the intake system (e.g., mounted thereon) and may be charged, for example, by an engine on which the intake system is installed and / or by regenerative braking.

[0034] Another aspect of the present invention provides an internal combustion engine of an automobile equipped with an intake system as described above. The engine is preferably a 4-stroke piston engine. The engine may have a displacement of no more than 4 liters, no more than 3 liters, or no more than 2 liters, although larger displacements are possible.

[0035] Another aspect of the present invention provides a vehicle comprising an internal combustion engine as described above. The vehicle may, for example, be a road vehicle, such as a car or a truck / van, or alternatively, an off-road vehicle.

[0036] The vehicle may include a control module arranged to control the operation of the two electric superchargers.

[0037] The control module can be arranged to provide the same power to each of the two electric superchargers during use. By always providing the same power to each of the two electric superchargers, control complexity is minimized. Alternatively, the control module can be arranged to individually control the power provided to each of the two electric superchargers, providing a different power to each of the two electric superchargers during use, for example, to maximize their operating efficiency.

[0038] The control module may be arranged to activate the electric superchargers only during transient engine operating modes. This may, for example, be in response to an increased throttle position. Alternatively, the control system may be arranged to also activate the electric superchargers at other times, for example, when there is a difference between the target power and the measured power, or a difference between the target boost pressure and the measured boost pressure.

[0039] It will be appreciated that the intake system is not limited to having exactly two electric superchargers, and that an intake system according to the present invention may also include additional electric superchargers. For example, the intake system may include a third electric supercharger arranged in series with, parallel with, or in a configurable arrangement with the two electric superchargers.

[0040] Another aspect of the present invention provides a method of operating an intake system of an internal combustion engine of an automobile, the method comprising delivering air to the internal combustion engine through the intake system; passing air through two electric superchargers provided in the intake system; and using the two electric superchargers to compress air flowing through the intake system prior to delivery to the internal combustion engine. The two electric superchargers may be arranged in series with each other or in parallel with each other. The method may be used in operating an intake system as described above and may include any steps associated with the normal operation of an intake system incorporating any of the features described above.The method may be used in operating an intake system in which two electric superchargers are permanently arranged in series with each other, or in which the two electric superchargers are permanently arranged in parallel with each other, or in which the two electric superchargers are provided in a configurable arrangement that can be selectively switched between a series configuration and a parallel configuration.

[0041] The method includes switching the two electric superchargers 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, during use of the engine.

[0042] According to a further aspect of the present invention, there is provided a valve assembly for a gas flow system comprising: a first and second valve element, wherein the first valve element is movable between an open position for permitting 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 permitting 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.

[0043] The valve assembly may optionally be a valve assembly for a gas flow system of an internal combustion engine of an automobile.

[0044] The first and second valve elements are capable of controlling the gas flow through a first and second flow path when the valve assembly is integrated into a gas flow system including the first and second flow paths. However, it is understood that the valve assembly may be provided separately for the gas flow system into which it is to be integrated.

[0045] The valve assembly of the present invention allows a gas flow system (e.g., a gas flow system of an automotive internal combustion engine) in which the valve assembly may be integrated, 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, number of parts, and control complexity of a gas flow system (e.g., a gas flow system of an automotive internal combustion engine). The present invention can be 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.

[0046] 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.

[0047] The actuator can be a rotary actuator or alternatively a linear actuator.

[0048] 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.

[0049] The first and second valve elements may have a fixed phase relationship with each other.

[0050] The first and second valve elements may be arranged to be rotated between their respective open and closed positions.

[0051] 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 channel may be used.

[0052] 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 be rotated between its open and closed positions. Alternatively, the first and second valve elements may be arranged to be pivoted about separate pivot axes, which may be parallel pivot axes.

[0053] The first and second valve elements may be angularly offset from each other 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, if each of the valve elements is arranged to rotate less than 90 degrees between its closed position and its maximum opening position.

[0054] The first and second valve elements can be fixed to a common shaft.

[0055] The common shaft can be directly coupled to a rotary output of the actuator. Alternatively, the common shaft can be coupled to a rotary or linear output of the actuator via a coupling mechanism that allows the common actuator to rotate the common shaft. Such a coupling mechanism can include, for example, one or more gears, cranks, or levers.

[0056] Alternatively, the first and second valve elements may each be fixed to separate shafts. In this case, a first of the shafts may be directly coupled to a rotary output of the actuator, or alternatively, may be coupled to a rotary or linear output of the actuator via a coupling mechanism. The second of the shafts may also be coupled to the output of the actuator via a further coupling mechanism, or alternatively, to the first of the shafts via a further coupling mechanism to enable the actuator to control the position of both the first and second valve elements.

[0057] 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 both the first and second flow paths when the respective valve element is in its closed position.

[0058] The valve assembly may further comprise a biasing system for biasing the valve assembly to a position in which one of the first and second valve elements is in its open position and the other of the first and second valve elements is in its closed position.

[0059] The first and second flow paths may be substantially parallel to each other at the position of the valve elements.

[0060] The valve assembly may further comprise a common housing, with the first and second valve elements placed within and / or mounted on the common housing. If the first and second valve elements are fixed to a common shaft, the common shaft may be rotatably mounted on the housing. Alternatively, the gas flow system may comprise separate housings for the first and second valve elements.

[0061] The valve assembly may comprise first and second flow channels, wherein the first valve element is operable to control the gas flow through the first flow channel, and wherein the second valve element is operable to control the gas flow through the second flow channel. The first flow channel may be arranged to form part of the first flow path, and the second flow channel may be arranged to form part of the second flow path when the valve assembly is integrated into a gas flow system including the first and second flow paths. The first and second flow channels may be provided by the common housing or, alternatively, by separate housings. In either case, the first and second flow channels may run substantially parallel to one another.

[0062] The first valve element may be arranged in the first flow channel, and the second valve element may be arranged in the second flow channel. Alternatively, one or both of the first and second valve elements may be arranged outside the first and second flow channels, for example, at the ends of the first and second flow channels.

[0063] The valve assembly may further comprise a third valve element movable between an open position for permitting 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, as described above, equally apply to the third valve element. In particular, the common actuator may also be arranged to control the position of the third valve element. It will be further appreciated that in some embodiments, the valve assembly may comprise more than three valve elements.

[0064] The third valve element may be arranged to operate out of phase with the first valve element and in phase with the second valve element.

[0065] Another aspect of the present invention provides a gas flow system (for example, a gas flow system of an automobile or for an internal combustion engine of an automobile) comprising first and second flow paths and a valve assembly as described above. The first valve element is operable to control the gas flow through the first flow path, and the second valve element is operable to control the gas flow through the second flow path. However, as mentioned above, it is understood that the valve assembly may be provided separately for the gas flow system into which it is to be incorporated.The first flow path can be open while the second flow path is closed by operating the actuator to move the first valve element to its open position (or maintain the first valve element therein) and to move the second valve element to its closed position (or maintain the second valve element therein), or vice versa. The first and second flow paths can be alternative flow paths arranged parallel to each other. The valve assembly can be operated 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).

[0066] If the valve assembly includes a third valve element, the gas flow system may further include a third flow path, wherein the third valve element is operable to control the flow of gases through the third flow path. In this case, the first, second, and third flow paths may each be open or closed as required by operation of the common actuator. The first, second, and third flow paths may be alternative flow paths arranged parallel to one another. The valve assembly is 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).

[0067] The gas flow system may be an intake system (for example, an intake system of an automobile or for an internal combustion engine of an automobile).

[0068] When the intake system includes 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.

[0069] When 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.

[0070] The gas flow system may be an exhaust system (e.g., an exhaust system of an automobile or for an internal combustion engine of an automobile). In this case, the first flow path may be a first exhaust flow path, and the second flow path may be an alternative exhaust flow path arranged parallel to the first exhaust flow path.

[0071] The valve assembly of the present invention may equally be used in any other gas flow system of an internal combustion engine of an automobile (besides those described above) in which it is desired to open at least one flow path during the firing of at least one other flow path.

[0072] Another aspect of the present invention provides an internal combustion engine (for example, an internal combustion engine of an automobile) equipped with a gas flow system as described above.

[0073] Another aspect of the present invention provides a vehicle comprising an engine as described above. The vehicle may, for example, be a road vehicle, such as a car or a truck / van, or alternatively, an off-road vehicle.

[0074] Another aspect of the present invention provides a valve assembly for a gas flow system (for example, a gas flow system of an internal combustion engine of an automobile), comprising: a first and second flow channel arranged to allow gas to flow therethrough; a first and second valve element, wherein the first valve element is movable between an open position in which gas flow through the first flow channel is permitted and a closed position in which gas flow through the first flow channel is restricted; and wherein the second valve element is movable between an open position in which gas flow through the second flow channel is permitted and a closed position in which gas flow through the second flow channel is restricted; and a common actuator arranged to control the position of each of the first and second valve elements.

[0075] The first and second valve elements may be arranged to operate out of phase with each other.

[0076] The valve assembly may generally include any of the features described above in connection with the first aspect of the present invention.

[0077] Another aspect of the present invention provides a valve assembly for a gas flow system (for example, a gas flow system of an internal combustion engine of an automobile), comprising: a first and second valve element, wherein the first valve element is movable between an open position for permitting 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 permitting 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.

[0078] The first and second valve elements may be fixed to a common shaft on which each of the first and second valve elements is arranged to be rotated between its open and closed positions.

[0079] Optionally, the first and second valve elements may be arranged to operate 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 operate in phase with each other. In particular, when the first and second valve elements are arranged to operate in phase with each other, the valve assembly may be included in an intake system of an automobile or for an internal combustion engine of an automobile, comprising first and second flow paths, the first flow path being arranged to discharge air from an outlet of a first electric supercharger and bypassing a second electric supercharger, and the second flow path being arranged to bypass the first electric supercharger and discharge 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.

[0080] Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples, and alternatives presented in the preceding paragraphs, in the claims, and / or in the following description and drawings, and in particular their individual features, may be considered independently of one another or in any combination. This means that all embodiments and / or features of any embodiment may be combined in any manner and / or combination, provided these features are not incompatible.The applicant reserves the right to amend any originally filed claim or to file any new claim accordingly, including the right to amend any originally filed claim to depend on and / or incorporate any feature of any other claim even though it has not been so claimed before. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 illustrates a car with an internal combustion engine of an automobile equipped with an intake system according to a possible embodiment of the present invention; Fig. Figure 2 schematically illustrates the engine, intake system and exhaust system of the vehicle from Fig. 1, where the Fig. 2, however, is not according to a possible embodiment of the present invention; the Fig. 3 to 5 schematically illustrate various internal combustion engines of automobiles equipped with intake systems not according to embodiments of the present invention; the Fig. 6 to 8 schematically illustrate various internal combustion engines of automobiles equipped with intake systems according to embodiments of the present invention; the Fig. 9a and Fig. 9b schematically illustrate a valve assembly from the Fig. 7 and Fig. 8 illustrated embodiment; and the Fig. 10 and Fig. 11 schematically illustrate internal combustion engines of automobiles equipped with intake systems according to still other embodiments of the present invention; Fig. Figure 12 schematically illustrates the engine, intake system and valve assembly of the vehicle from Fig. 1; the Fig. 13, Fig. 14 and Fig. 15 schematically illustrate the valve assembly during different operating modes of the intake system; the Fig. 16 and Fig. 17 schematically illustrate various internal combustion engines of automobiles equipped with intake systems comprising valve assemblies according to other possible embodiments of the present invention; and Fig. 18 illustrates a portion of an exhaust system including a valve assembly according to another possible embodiment of the present invention. DETAILED DESCRIPTION Embodiment of Figures 1 and 2, wherein Figure 2 is not according to an embodiment of the present invention

[0082] Fig. Figure 1 illustrates a car 100 comprising an internal combustion engine 1 of an automobile. The engine 1 is equipped with an exhaust system 2 for removing combustion gases from the engine and an intake system 3 for supplying air to the engine, as shown schematically in Fig. 2. The engine 1 may generally be any type of automobile engine, for example a 4-stroke engine with 4 cylinders and a displacement of approximately 2 l.

[0083] The intake system 3 includes an air filter 4 through which air enters the intake system. The intake system 3 further includes a conventional turbocharger 5, which includes a turbine arranged to be driven by the exhaust gases flowing through the exhaust system 2, and a compressor driven by the turbine and 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.

[0084] The intake system 3 further includes first and second electric superchargers 6, 7. Each of the electric superchargers 6, 7 includes a compressor arranged to compress air flowing through the intake system 3 prior to delivery to the engine 1, and includes an electric motor arranged to drive the compressor. The electric superchargers 6, 7 are of the same model and each have an identical connected load of 5 kW.

[0085] The first and second electric superchargers 6, 7 are powered by a main battery 20 of the vehicle 100, and their operation is controlled by a control module 21, which may be the main ECU of the vehicle 100 or, alternatively, a separate controller. The control module 21 is arranged to operate the first and second electric superchargers 6, 7 jointly and to always provide the same power to each of the first and second electric superchargers 6, 7 in order to minimize the control complexity of the charging system.

[0086] The first and second electric superchargers 6, 7 are arranged in series with each other along a supercharged flow path 8, such that air flowing along the supercharged flow path 8 passes through and is compressed by the first electric supercharger 6 before passing through and being further compressed by the second electric supercharger 7. The first and second electric superchargers 6, 7 are also arranged in series with and downstream of the turbocharger 5, and thus are all 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.

[0087] The first and second electric superchargers 6, 7 are arranged on opposite sides of the engine 1, although they could equally be arranged on the same side of the engine.

[0088] The supercharged flow path 8 is provided with a common charge cooling device 9 in the form of a water-charged air cooler for cooling air compressed by the first and second electric superchargers 6, 7.

[0089] The supercharged flow path 8 leads to a throttle device 10 operated to control the operation of the engine 1 and an intake manifold 11 for discharging the air from the intake system 3 directly into the cylinders of the engine 1, the first and second electric superchargers 6, 7 being arranged upstream of the throttle device 10 and the intake manifold 11.

[0090] The intake system 3 further includes a bypass line 12 operable to selectively bypass 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 parallel to the boosted flow path 8 in which the first and second electric superchargers 6, 7 are provided. The bypass line 12 is provided with a bypass valve 13 that can be selectively opened to allow air flowing through the intake system 3 to bypass the first and second electric superchargers 6, 7, and that can be closed to close the bypass line 12 such that air flowing through the intake system flows via the boosted flow path 8 and through the first and second electric superchargers 6, 7.The bypass line 12 is provided with its own charge cooling device 14 in the form of a water-charged air cooler for cooling air that has been compressed by the turbocharger 5 and flows through the bypass line 12 (instead of via the supercharged flow path 8). The bypass line 12 also leads to the throttle device 10 and the intake manifold 11.

[0091] In other embodiments, the two charge cooling devices 9, 14 may be replaced by a single charge cooling device arranged in series with and downstream of the turbocharger 5 and both the first and second electric superchargers 6, 7.

[0092] The operation of the intake system 3 is now described.

[0093] During normal steady-state operation of the engine 1, the bypass valve 13 is held in its open position by an actuator. In this state, air delivered to the engine 1 through the intake system 3 is compressed by the turbocharger 5 and then flows through the bypass line 12, thereby bypassing the boost flow path 8 and the first and second electric superchargers 6, 7. The compressed air is then cooled by the bypass line's charge cooling device 14 before flowing through the throttle device 10 and entering the engine 1 via the intake manifold 11.

[0094] When the throttle position is increased, the actuator of the bypass valve 13 is controlled to move the bypass valve to its closed position, thereby closing the bypass line 12 and causing air flowing through the intake system 3 to flow via the boosted flow path 8. The first and second electric superchargers 6, 7 are actuated by the control module 21 and serve to further compress the air already compressed by the turbocharger 5, thereby providing a further increase in air pressure. The further compressed air is then cooled by the boosted flow path charge cooling device 9 before flowing through the throttle device 10 and entering the engine 1 via the intake manifold 11.In this operating mode, the first and second electric superchargers 6, 7 provide additional compression of the air delivered to the engine 1, thereby increasing the torque and power available from the engine after the throttle position has been increased, providing a faster response to the increased throttle position. The first and second electric superchargers 6, 7 also ramp up faster than the turbocharger 5 and therefore serve to reduce the effects of turbo lag inherent in the turbocharger.

[0095] When the engine 1 returns to steady-state operation, the first and second electric superchargers 6, 7 can be deactivated and the bypass valve 13 can be opened to reopen the bypass line 12.

[0096] Since the maximum air flow through the first and second electric superchargers 6, 7 is limited by the size and speed of the electric superchargers, the supercharged flow path 8 can only be used below a predetermined engine speed and / or a predetermined air mass flow rate. Embodiment of Figure 3, not according to an embodiment of the present invention

[0097] Fig. Figure 3 schematically illustrates an engine 101 equipped with an intake system 103. The embodiment of Fig. 3 is the embodiment of Fig. 2 is generally similar and is therefore not described in full and instead only the differences compared to the embodiment of Fig. 2. Features that have already been described in connection with the embodiment of Fig. 2 are given equivalent reference numerals in the 100 series.

[0098] As with the embodiment of Fig. 2, the first and second electric superchargers 106, 107 are arranged in series with each other and also in series with and downstream of a conventional turbocharger 105. In this embodiment, rather than a single bypass conduit operable to bypass both the first and second electric superchargers 106, 107, the intake system 103 instead includes a first bypass conduit 112a operable to bypass the first electric supercharger 106 and a separate second bypass conduit 112b operable to bypass the second electric supercharger 107.

[0099] In this embodiment, it is possible to bypass both the first and second electric superchargers 106, 107 by maintaining the bypass valves 113a, 113b of the bypass lines 112a, 112b in the open positions. The bypass valves 113a, 113b can then be moved to closed positions when it is desired to operate the first and second electric superchargers 106, 107 to further compress air delivered to the engine 101 through the intake system 103.

[0100] As with the embodiment of Fig. 2, the intake system 103 comprises two charge cooling devices 109, 114. Instead of a first charge cooling device 9 in the charged flow path 8 for cooling air compressed by the first and second electric superchargers 6, 7, and a second charge cooling device 14 in the bypass line 12 for cooling air compressed by the turbocharger 5, but bypassing the first and second electric superchargers, the intake system 103 of Fig. 3, however, a first charge cooler 109 in series with and downstream of the turbocharger 105 and the first electric supercharger 106 for cooling air compressed by the turbocharger and optionally also by the first electric supercharger, and a second charge cooling device 114 in series with and downstream of the second electric supercharger 107 for cooling air additionally compressed by the second electric supercharger. Embodiment of Figure 4, not according to an embodiment of the present invention

[0101] Fig. Figure 4 schematically illustrates an engine 201 equipped with an intake system 203. The embodiment of Fig. 3 has many similarities with the design of Fig. 2 and is therefore not described in full and instead only the differences compared to the embodiment of Fig. 2. Features that have already been described in connection with the embodiment of Fig. 2 are given equivalent reference numerals in the 200 series and are not described individually.

[0102] As with the embodiment of Fig. 2, the intake system 203 includes first and second electric superchargers 206, 207. However, instead of being arranged in series with each other, in this embodiment the first and second electric superchargers are arranged in parallel with each other in parallel boosted flow paths 208a, 208b. The first and second electric superchargers 206, 207 are also arranged in series with and downstream of a conventional turbocharger 205. By arranging the electric superchargers 206, 207 in parallel with each other, it is possible to increase the maximum air mass flow rate achievable by the two electric superchargers. It is therefore possible to increase the engine speed range over which the electric superchargers 206, 207 are effective in compressing the air for delivery to the engine 201 (albeit with a reduced boost pressure at lower engine speeds).

[0103] The first and second electric superchargers 206, 207 are arranged on the same side of the engine 101, although they could equally be arranged on opposite sides of the engine.

[0104] The intake system 203 includes a single bypass line 212 that includes a bypass valve 213 that can be held in an open position to allow air flowing through the intake system to bypass the first and second electric superchargers 206, 207. The bypass valve 213 can then be moved to a closed position when it is desired to use the first and second electric superchargers 106, 107 to further compress air delivered to the engine 101 through the intake system 103.

[0105] The intake system 203 includes a single charge cooling device 209 arranged to cool air bypassing the first and second superchargers 206, 207 (when the bypass line 212 is active), as well as to cool air compressed by one of the electric superchargers in addition to the turbocharger 205 (when the bypass line 212 is closed). In other embodiments, multiple charge cooling devices may similarly be present, for example, a first charge cooling device arranged in series with and downstream of the first and second superchargers 206, 207 to cool air compressed by the first and second electric superchargers in addition to the turbocharger 205, and a second charge cooling device arranged in the bypass line 212 to cool air bypassing the first and second superchargers 206, 207.

[0106] The intake system 203 from Fig. 4 is generally used in the same way as that of Fig. 2, wherein the first and second electric superchargers 206, 207 are activated to increase air pressure during transient engine operating modes, but are bypassed during steady-state operation and at higher engine speeds. Due to the parallel arrangement of the electric superchargers 206, 207, it may be possible to operate the electric superchargers at higher engine speeds and higher air mass flow rates. Embodiment of Figure 5, not according to an embodiment of the present invention

[0107] Fig. Figure 5 schematically illustrates an engine 301 equipped with an intake system 303. Features already described in connection with the embodiment of Fig. 2 are given equivalent reference numerals in the 300 series and are not described individually. The embodiment of Fig. 5 is the embodiment of Fig. 4 are generally similar and therefore only the differences compared to the embodiment of Fig. 4 described.

[0108] As with the embodiment of Fig. 4, the first and second electric superchargers 306, 307 are arranged parallel to each other. However, in this embodiment, the first and second electric superchargers 306, 307 are arranged parallel to the turbocharger 305 instead of in series with the turbocharger. Embodiment of Figure 6

[0109] Fig. Figure 6 schematically illustrates an engine 401 equipped with an exhaust system 402 and an intake system 403 according to another possible embodiment of the present invention.

[0110] The intake system 403 includes an air filter 404 through which air enters the intake system. The intake system 403 further includes a conventional turbocharger 405, which includes a turbine arranged to be driven by the exhaust gases flowing through the exhaust system 402, and a compressor driven by the turbine and 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.

[0111] The intake system 403 further includes first and second electric superchargers 406, 407. Each of the electric superchargers 406, 407 includes a compressor arranged to compress air flowing through the intake system 403 prior to delivery to the engine 401, and an electric motor arranged to drive the compressor. The electric superchargers 406, 407 are of the same model and each have an identical connected load of 5 kW.

[0112] The first and second electric superchargers 406, 407 are powered by a main battery 420 of the vehicle, and their operation is controlled by a control module 421, which may be the vehicle's main ECU or, alternatively, a separate controller. The control module 421 is arranged to operate the first and second electric superchargers 406, 407 jointly and to always provide the same power to each of the first and second electric superchargers 406, 407 to minimize the control complexity of the charging system.

[0113] The first and second electric superchargers 406, 407 are provided in a configurable arrangement that can be selectively switched 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, during use of the engine 401. The first and second electric superchargers 406, 407 are both arranged in series with and downstream of the turbocharger 405 and thus are all 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.

[0114] The first and second electric superchargers 406, 407 are disposed on opposite sides of the engine 401, although they could equally be disposed on the same side of the engine.

[0115] When the first and second electric superchargers 406, 407 are in the series configuration, the first electric supercharger 406 is arranged in series with and upstream of the second electric supercharger 407. An outlet of the first electric supercharger is connected to an inlet of the second electric supercharger 407 through a first flow path 408a for delivering air from the first electric supercharger to the second electric supercharger. The first flow path 408a is provided with a first valve 413a operated by an actuator to control the airflow through the first flow path from the first electric supercharger to the second electric supercharger.

[0116] The intake system 403 further includes a second flow path 408b for discharging air from the outlet of the first electric supercharger 406 and for bypassing the second electric supercharger 407 when the first and second electric superchargers 406, 407 are in the parallel configuration. The second flow path 408b is provided with a second valve 413b operated by an actuator to control the airflow through the second flow path.

[0117] The intake system 403 further includes a third flow path 408c for bypassing the first electric supercharger 406 and delivering air to the second electric supercharger 407 when the first and second electric superchargers 406, 407 are in the parallel configuration. The third flow path 408c is provided with a third valve 413c, which is operated by an actuator to control the airflow through the third flow path.

[0118] The first, second, and third valves 413a, 413b, 413c each comprise a valve element, for example, a butterfly valve element, placed within a housing. The housing of each of the first, second, and third valves 413a, 413b, 413c forms part of a corresponding one of the first, second, and third flow paths 408a, 408b, 408c.

[0119] The first, second, and third flow paths 408a, 408b, 408c together provide a configurable charged flow path.

[0120] If it is desired to operate the first and second electric superchargers 406, 407 in the series configuration, the first valve 413a may be held in an open position to thereby open the first flow path 408a, while the second and third valves 413b, 413c are held in the closed positions to thereby close the second and third flow paths 408b, 408c. In this configuration, air flowing along the supercharged flow path passes through the first electric supercharger 306 and is compressed thereby before passing through the second electric supercharger 407 and being further compressed thereby.

[0121] Conversely, if it is desired to operate the first and second electric superchargers 406, 407 in the parallel configuration, the first valve 413a may be maintained in a closed position to thereby close the first flow path 408a, while the second and third valves 413b, 413c are maintained in the open positions to thereby close the second and third flow paths 408b, 408c. In this configuration, a portion of the air flowing along the supercharged flow path flows through the first electric supercharger 306 and is compressed thereby, and the remainder of the air flowing through the supercharged flow path flows through the second electric supercharger 407 and is further compressed thereby.

[0122] The intake system 403 further includes a bypass conduit 412 operable to selectively bypass the boosted flow path 408a, 408b, 408c (including the first and second electric superchargers 406, 407). The bypass line 412 is arranged in series with and downstream of the turbocharger 5, but runs parallel to the boosted flow path 408a, 408b, 408c and each of the first and second electric superchargers 406, 407. The bypass line 412 is provided with a bypass valve 413d that is selectively opened to allow air flowing through the intake system 403 to bypass the first and second electric superchargers 406, 407, and that can be closed to close the bypass line 412 such that air flowing through the intake system flows via the boosted flow path 408a, 408b, 408c and through the first and second electric superchargers 406, 407.

[0123] The intake system further includes a charge cooling device 409, a throttle device 410, and an intake manifold 411 arranged in series with and downstream of each of the turbocharger 405 and the first and second electric superchargers 406, 407.

[0124] The operation of the intake system 403 will now be described.

[0125] During normal steady-state operation of engine 401, bypass valve 413d is maintained in its open position. In this state, air delivered to engine 401 through intake system 403 is compressed by turbocharger 405 and then flows through bypass conduit 412, thereby bypassing the boosted flow path and the first and second electric superchargers 406, 407. The compressed air is then cooled by charge cooling device 409 before flowing through throttle device 410 and entering engine 401 via intake manifold 411.

[0126] When the throttle position is increased, the first and second electric superchargers 406, 407 may be operated to further compress the air delivered to the engine 401 through the intake system 403 to provide a faster response to the increased throttle position and combat turbo lag. The vehicle's ECU determines which configuration should be used. This determination may be based, for example, on the throttle position and / or the engine speed or the mass air flow rate. For example, the series configuration may be selected when a large increase in throttle angle is detected and / or when the engine speed is low, and the parallel configuration may be selected at higher engine speeds.

[0127] If it is determined that the first and second electric superchargers 406, 407 should be operated in the series configuration, the first valve is moved to or held in its open position, and the second and third valves are moved to or held in their closed positions. In this configuration, the first and second electric superchargers 406, 407 are operated together in series to sequentially further compress air flowing through the intake system 403 via the first flow path 408a.

[0128] Alternatively, if it is determined that the first and second electric superchargers 406, 407 should be operated in the parallel configuration, the first valve is moved to or held in its closed position, and the second and third valves are moved to or held in their open positions. In this configuration, the first and second electric superchargers 406, 407 are operated together in parallel, and each compresses a portion of the air flowing through the intake system 403 via the second and third flow paths 408b, 408c.

[0129] When the engine 401 returns to steady-state operation, the first and second electric superchargers 406, 407 may be deactivated and the bypass valve 413d may be opened to reopen the bypass line 412, thereby allowing air flowing through the intake system 403 to bypass the boosted flow path and the first and second electric superchargers 406, 407.

[0130] The configurable arrangement described above allows the most advantageous configuration of the two electric superchargers 406, 407 to be selected for any given operating condition of the engine 401, such that the overall performance of the charging system can be optimized over a wider range of operating conditions. Embodiment of Figure 7

[0131] Fig. Figure 7 schematically illustrates an engine 501 equipped with an intake system 503 according to another possible embodiment of the present invention. The embodiment of Fig. 7 is the embodiment of Fig. 6 is generally similar and is therefore not described in full and instead only the differences compared to the embodiment of Fig. 6. Features that have already been described in connection with the embodiment of Fig. 6 are given equivalent reference numerals in the 500 series.

[0132] The Fig. The intake system illustrated in Figure 7 has the same general structure as that shown in Fig. 6 and is operated in the same manner. Instead of using three separate valves, each operated by a separate actuator to control the configurable series / parallel configuration of the first and second electric superchargers, the embodiment of Fig. 7 the three separate valves by a single integrated valve assembly 530, as shown in the Fig. 7, Fig. 8, Fig. 9a and Fig. 9b illustrates.

[0133] The valve assembly 530 includes a common housing 531 that provides three separate valve channels 532a, 532b, 532c. The first valve channel 532a forms part of the first flow path 508a for discharging air from the first electric supercharger 506 to the second electric supercharger 507 when the first and second electric superchargers are operated in the series configuration. The second valve channel 532b forms part of the second flow path 508b for discharging air from the first electric supercharger 506 and bypassing the second electric supercharger 507 when the first and second electric superchargers are operated in the parallel configuration. The third valve channel 532c forms part of the third flow path 508c for bypassing the first electric supercharger 506 and delivering air to the second electric supercharger 507 when the first and second electric superchargers are operated in the parallel configuration.

[0134] Each of the first, second, and third valve channels 532a, 532b, 532c is provided with a corresponding valve element 513a, 513b, 513c, for example, a butterfly valve element. Each valve element 513a, 513b, 513c can be moved between a closed position, in which it serves to prevent air flow through its corresponding valve channel 532a, 532b, 532c (and therefore through a corresponding one of the first, second, and third flow paths 508a, 508b, 508c), and an open position, in which fluid flow is enabled. Each valve element 513a, 513b, 513c can be arranged to at least substantially completely seal its corresponding valve channel 532a, 532b, 532c when in the closed position. In addition, one or more of the valve elements 513a, 513b, 513c may include spring preload.

[0135] The three valve elements 513a, 513b, 513c are arranged along a common shaft 534, which is rotatably mounted on the common housing 531, and are fixedly attached thereto. The first valve element 513a is arranged to be out of phase with the second and third valve elements 513b, 513c, such that when the first valve element 513a is in its open position, the second and third valve elements 513b, 513c are in their closed positions, and vice versa.

[0136] The common shaft 534 can be rotated between a first position and a second position. When the common shaft 534 is in its first position, the first valve element 513a is in its open position and the second and third valve elements 513b, 513c are in their closed positions, as shown in Fig. 9a. In this position, the first flow path 508a remains open, while the second and third flow paths remain closed, and thus it is possible to operate the first and second electric superchargers 506, 507 in the series configuration. When the common shaft 534 is in its second position, the first valve element 513a is in its closed position and the second and third valve elements 513b, 513c are in their open positions, as shown in Fig. 9b. In this position, the first flow path 508a is closed, while the second and third flow paths are open, thus allowing the first and second electric superchargers 506, 507 to be operated in parallel configuration.

[0137] The valve assembly 530 is provided with a common actuator 535, for example, a rotary actuator, operable to rotate the common shaft 534 to thereby control the position of the first, second, and third valve elements. The valve assembly 530 is further provided with a biasing element 536 for biasing the common shaft 534 toward its first position. By biasing the common shaft 534 in this direction, it is possible to achieve a fail-safe mode wherein the first valve element 513a is in its open position and the second and third valve elements 513a, 513c are in their closed positions, such that the configurable arrangement of electric superchargers defaults to the in-line configuration. However, in other embodiments, a biasing element could equally serve to bias the common shaft in the opposite direction.

[0138] The intake system 503 from Fig. 7 is made in the same way as the one from Fig. 6. However, if the intake system is made of Fig. 7 that the first and second electric superchargers 506, 507 should be operated in either the series configuration or the parallel configuration, the desired configuration can be achieved simply by controlling the single common actuator 535 to jointly control the position of the first, second and third valve elements 513a, 513b, 513c.

[0139] By replacing the first, second and third valves of the embodiment of Fig. 6 by a single valve assembly 530 comprising three valve elements provided within a common housing and operated by a common actuator, it is possible to reduce the number of parts, cost, weight and complexity of the configurable arrangement of the electric superchargers.

[0140] In other embodiments, it is possible for an integrated valve assembly to be arranged to control the air flow through only two of the first, second, and third flow paths 508a, 508b, 508c. For example, Fig. 10 schematically shows an alternative integrated valve assembly 530 compared to that shown in Fig. 7. In this alternative embodiment, the valve assembly 530 includes only two valve elements 513b, 513c, which are provided within a common housing and mounted on a common shaft and which are arranged to control the air flow through the second and third flow paths 508b, 508c. In this embodiment, the two valve elements 513b, 513c are arranged to be operated in phase with each other. A separate valve 513a, operated by a separate actuator, is used to control the air flow through the first flow path 508a. As a further example, Fig. 11 schematically illustrates another alternative valve assembly 530 that includes only two valve elements 513a, 513c provided within a common housing and mounted on a common shaft, and arranged to control the airflow through the first and third flow paths 508a, 508c. In this embodiment, the two valve elements 513a, 513c are arranged to be operated out of phase with each other. A separate valve 513b, operated by a separate actuator, is used to control the airflow through the second flow path 508b.

[0141] Fig. Figure 12 schematically illustrates an engine 1001, which may be any type of automobile engine, for example a 4-stroke engine with 4 cylinders and a displacement of approximately 2 l.

[0142] The intake system 1003 includes an air filter 1004 through which air enters the intake system. The intake system 1003 further includes a conventional turbocharger 1005, which includes a turbine arranged to be driven by the exhaust gases flowing through the exhaust system 1002, and a compressor driven by the turbine and 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 1005 will not be discussed further.

[0143] The intake system 1003 further includes first and second electric superchargers 1006, 1007. Each of the electric superchargers 1006, 1007 includes a compressor arranged to compress air flowing through the intake system 1003 prior to delivery to the engine 1001, and an electric motor arranged to drive the compressor. The electric superchargers 1006, 1007 are of the same model and each have an identical connected load of 5 kW.

[0144] The first and second electric superchargers 1006, 1007 are powered by a main battery 1020 of the vehicle, and their operation is controlled by a control module 1021, which may be the vehicle's main ECU or, alternatively, a separate controller. The control module 1021 is arranged to operate the first and second electric superchargers 1006, 1007 jointly and to always provide the same power to each of the first and second electric superchargers 1006, 1007 to minimize the control complexity of the charging system.

[0145] The first and second electric superchargers 1006, 1007 are provided in a configurable arrangement that can be selectively switched during use of the engine 1001 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 1006 before flowing through the second electric supercharger 1007, while the parallel configuration is a configuration in which a first airflow flows through the first electric supercharger (but not through the second electric supercharger) while a parallel second airflow flows through the second electric supercharger (but not through 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 1050 according to an embodiment of the present invention, which is described in more detail below.

[0146] The first and second electric superchargers 1006, 1007 are both arranged in series with and downstream of the turbocharger 1005 and thus are all 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.

[0147] The first and second electric superchargers 1006, 1007 are disposed on opposite sides of the engine 1001, although they could equally be disposed on the same side of the engine.

[0148] When the first and second superchargers 1006, 1007 are in the series configuration, an outlet of the first electric supercharger is connected to an inlet of the second electric supercharger 1007 through a first flow path 1008a to deliver air from the first electric supercharger to the second electric supercharger.

[0149] The intake system 1003 further includes a second flow path 1008b for discharging air from the outlet of the first electric supercharger 1006 and for bypassing the second electric supercharger 1007 when the first and second electric superchargers 1006, 1007 are in the parallel configuration.

[0150] The intake system 1003 further includes a third flow path 1008c for bypassing the first electric supercharger 1006 and delivering air to the second electric supercharger 1007 when the first and second electric superchargers 1006, 1007 are in the parallel configuration.

[0151] The first, second and third flow paths 1008a, 1008b, 1008c all run parallel to each other and together provide a configurable charged flow path.

[0152] The intake system is provided with a valve assembly 1050 for selectively switching the first and second electric superchargers 1006, 1007 between the series and parallel configurations. The valve assembly 1050 includes a housing 1051 that provides first, second, and third flow channels 1052a, 1052b, 1052c, as schematically shown in the Fig. 13 and Fig. 14. The first, second, and third flow channels run substantially parallel to one another. The first flow channel 1052a forms a portion of the first flow path 1008a for delivering air from the first electric supercharger 1006 to the second electric supercharger 1007 when the first and second electric superchargers are operated in the series configuration. The second flow channel 1052b forms a portion of the second flow path 1008b for delivering air from the first electric supercharger 1006 and bypassing the second electric supercharger 1007 when the first and second electric superchargers are operated in the parallel configuration. The third flow channel 1052c forms a portion of the third flow path 1008c for bypassing the first electric supercharger 1006 and delivering air to the second electric supercharger 1007 when the first and second electric superchargers are operated in the parallel configuration.

[0153] Each of the first, second and third flow channels 1052a, 1052b, 1052c is provided with a corresponding valve element 1053a, 1053b, 1053c, for example a butterfly valve element, as shown schematically in the Fig. 13 and Fig. 14. Each valve element 1053a, 1053b, 1053c is rotatable between a closed position, in which it serves to prevent air flow through its respective flow channel 1052a, 1052b, 1052c (and therefore through its respective flow path 1008a, 1008b, 1008c), and an open position, in which fluid flow is enabled. Each valve element 1053a, 1053b, 1053c may be arranged to at least substantially completely seal its respective flow channel 1052a, 1052b, 1052c, thereby sealing its respective flow path 1008a, 1008b, 1008c when in the closed position.

[0154] The first, second and third valve elements 1053a, 1053b, 1053c are each arranged along a common pivot axis and fixed to a common shaft 1054, as shown schematically in Fig. 15. The common shaft 1054 is rotatably mounted on the housing 1051. The common shaft 1054 is connected to an output of a common actuator 1055 (as also shown in Fig. 15) which is operable to rotate the common shaft to thereby control the position of each of the first, second and third valve elements 1053a, 1053b, 1053c.

[0155] The second and third valve elements 1053b, 1053c are offset from the first valve element 1053a by approximately 90°. The second and third valve elements are therefore arranged to operate approximately 90 degrees out of phase with the first valve element 1053a, such that when the first valve element 1053a is in its closed position, the second and third valve elements 1053b, 1053c are each in their maximum opening positions. The second and third valve elements 1053b, 1053c are not angularly offset from each other and are arranged to operate in phase with each other. The first, second, and third valve elements 1053a, 1053b, 1053b have a fixed phase relationship because each is fixed to the common shaft 1054.

[0156] The common actuator 1055 is operable to rotate the common shaft 1054 into (or maintain the common shaft therein) a first position in which the first valve element 1053a is in a maximum opening position and the second and third valve elements 1053b, 1053c are in their closed positions, as schematically shown in Fig. 13. In this position, the first flow path 1008a remains open, while the second and third flow paths 1008b, 1008c remain closed, and thus it is possible to operate the first and second electric superchargers 1006, 1007 in the series configuration. The common actuator can also be operated to rotate the common shaft 1054 into a second position (or to hold the common shaft therein), in which the first valve element 1053a is in its closed position and the second and third valve elements 1053b, 1053c are in their maximum opening positions, as schematically shown in Fig. 14. In this position, the first flow path 1008a is closed, while the second and third flow paths 1008b, 1008c are open, and thus it is possible to operate the first and second electric superchargers 1006, 1007 in the parallel configuration.

[0157] The valve assembly 1050 is further provided with a biasing element 1056 for biasing the common shaft 1054 toward its first position. By biasing the common shaft 1054 in this direction, it is possible to achieve a fail-safe mode, with the first valve element 1053a in its open position and the second and third valve elements 1053b, 1053c in their closed positions, such that the configurable arrangement of electric superchargers defaults to the in-line configuration. However, in other embodiments, a biasing element could equally serve to bias the common shaft in the opposite direction.

[0158] The intake system 1003 further includes a bypass conduit 1012 operable to selectively bypass the boosted flow path 1008a, 1008b, 1008c (including the first and second electric superchargers 1006, 1007). The bypass line 1012 is arranged in series with and downstream of the turbocharger 1005, but runs parallel to the boosted flow path 1008a, 1008b, 1008c and each of the first and second electric superchargers 1006, 1007. The bypass line 1012 is provided with a bypass valve 1013 that can be selectively opened to allow air flowing through the intake system 1003 to bypass the first and second electric superchargers 1006, 1007, and that can be closed to close the bypass line 1012 such that air flowing through the intake system flows via the boosted flow path 1008a, 1008b, 1008c and through the first and second electric superchargers 1006, 1007.

[0159] The intake system further includes a charge cooling device 1009, a throttle device 1010, and an intake manifold 1011 arranged in series with and downstream of each of the turbocharger 1005 and the first and second electric superchargers 1006, 1007.

[0160] The operation of the intake system 1003 and the valve assembly 1050 will now be described.

[0161] During normal steady-state operation of the engine 1001, the bypass valve 1013 is maintained in its open position. In this state, air delivered to the engine 1001 through the intake system 1003 is compressed by the turbocharger 1005 and then flows through the bypass line 1012, thereby bypassing the boosted flow path 1008a, 1008b, 1008c and the first and second electric superchargers 1006, 1007. The compressed air is then cooled by the charge cooling device 1009 before flowing through the throttle device 1010 and entering the engine 1001 via the intake manifold 1011.

[0162] When the throttle position is increased, the first and second electric superchargers 1006, 1007 may be operated to further compress the air delivered to the engine 1001 through the intake system 1003 to provide a faster response to the increased throttle position and combat turbo lag. The vehicle's ECU determines which configuration should be used. This determination may be based, for example, on the throttle position and / or the engine speed or the mass air flow rate. For example, the series configuration may be selected when a large increase in throttle angle is detected and / or when the engine speed is low, and the parallel configuration may be selected at higher engine speeds.

[0163] If it is determined that the first and second electric superchargers 1006, 1007 should be operated in the series configuration, the common actuator 1055 is operated to move the common shaft 1054 to its first position (or to maintain the common shaft therein) such that the first flow path 1008a is open while the second and third flow paths 1008b, 1008c remain closed. In this configuration, the first and second electric superchargers 1006, 1007 are operated together in series to further sequentially compress air flowing through the intake system 1003 via the first flow path 1008a.

[0164] Alternatively, if it is determined that the first and second electric superchargers 1006, 1007 should be operated in the parallel configuration, the common actuator 1055 is operated to move the common shaft 1054 to its second position (or to maintain the common shaft therein) such that the first flow path 1008a is closed while the second and third flow paths 1008b, 1008c are open. In this configuration, the first and second electric superchargers 1006, 1007 are operated together in parallel, and each compresses a portion of the air flowing through the intake system 1003 via the second and third flow paths 1008b, 1008c.

[0165] When the engine 1001 returns to steady-state operation, the first and second electric superchargers 1006, 1007 may be deactivated and the bypass valve 1013 may be opened to reopen the bypass line 1012, thereby allowing air flowing through the intake system 1003 to bypass the boosted flow path 1008a, 1008b, 1008c and the first and second electric superchargers 1006, 1007.

[0166] The configurable arrangement described above allows the most advantageous configuration of the two electric superchargers 1006, 1007 to be selected for any given operating condition of the engine 1001, such that the overall performance of the charging system can be optimized over a wider range of operating conditions.

[0167] The use of a common valve assembly 1050 for controlling the opening and closing of the first, second and third flow paths 1008a, 1008b, 1008c allows a reduction in cost, weight, number of parts 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 1008a, 1008b, 1008c.

[0168] In the embodiment described above, the valve assembly 1050 comprises three valve elements 1053a, 1053b, 1053c arranged to open and close three different flow paths 1008a, 1008b, 1008c arranged parallel to each other in a gas flow system. In other embodiments, however, a valve assembly may comprise only two valve elements arranged to open and close two different flow paths. For example, the Fig. 16 and Fig. 17 two alternative embodiments corresponding to the embodiment of Fig. 12 in terms of structure and operation in general. Already with regard to the embodiment of Fig. 12 described features contain reference numerals in the 1100 or 1200 series and only the differences compared to the embodiment of Fig. 12 described.

[0169] In the embodiment of Fig. 16, the valve assembly 1150 comprises only two flow channels, each forming part of a first flow path 1108a for discharging air from the outlet of the first electric supercharger 1106 to the inlet of the second electric supercharger 1107 and a second flow path 1108c for bypassing the first electric supercharger 1106 and discharging air to the inlet of the second electric supercharger 1107. In this embodiment, first and second valve elements 1153a, 1153c of the valve assembly 1150 are fixed to a common shaft 1154 and arranged to be controlled by a common actuator 1155 to open and close the first and second flow paths 1108a, 1108c. The two valve elements 1153a, 1153c are arranged to be operated out of phase with each other.A separate valve 1153b, controlled by a separate actuator, is used to open and close another flow path 1108b for discharging air from the first electric supercharger 1106 and bypassing the second electric supercharger 1107.

[0170] It will be appreciated that in another embodiment, a similar valve assembly could equally be arranged to control flow path 1108a for discharging air from the outlet of the first electric supercharger 1106 to the inlet of the second electric supercharger 1107 and flow path 1108b for discharging air from the first electric supercharger 1106 and bypassing the second electric supercharger 1107. In such an embodiment, flow paths 1108a, 1108b may be considered first and second flow paths within the meaning of the appended claims.

[0171] In the embodiment of Fig. 17, the valve assembly 1250 comprises only two flow channels, each forming part of a first flow path 1208b for discharging air from the first electric supercharger 1206 and bypassing the second electric supercharger 1207, and a second flow path 1208c for bypassing the first electric supercharger 1206 and discharging air to the inlet of the second electric supercharger 1207. In this embodiment, first and second valve elements 1253b, 1253c of the valve assembly 1250 are fixed to a common shaft 1254 and arranged to be controlled by a common actuator 1255 to open and close the first and second flow paths 1208b, 1208c. The two valve elements 1253b, 1253c are arranged to be operated in phase with each other.A separate valve 1253a, controlled by a separate actuator, is used to open and close another flow path 1208a for discharging air from the outlet of the first electric supercharger 1206 to the inlet of the second electric supercharger 1207.

[0172] It will be appreciated that a valve assembly according to the present invention may also be used in other intake and exhaust systems where it is desired to open and close multiple gas flow paths. For example, Fig.18 schematically shows a portion of an exhaust system 1301 that divides into a first exhaust flow path 1302 and an alternative exhaust flow path 1303 arranged parallel to the first exhaust flow path. The exhaust system 1301 is provided with a valve assembly 1304 comprising first and second flow channels, each forming a part of the first exhaust flow path 1302 and the alternative exhaust flow path 1303. The valve assembly 1304 further comprises first and second valve elements 1305, 1306, each arranged to open and close a corresponding one of the first exhaust flow path 1302 and the alternative exhaust flow path 1303.The first and second valve elements 1305, 1306 are fixed to a common shaft 1308 and are arranged to be operated out of phase with each other, such that when the first valve element 1305 is in its open position, the second valve element 1306 is in its closed position, and vice versa. The valve assembly 1304 includes a common actuator 1307 for controlling the position of each of the first and second valve elements 1305, 1306. By operating the common actuator 1307, it is possible to open one of the first exhaust flow path 1302 and the alternative exhaust flow path 1303 while closing the other of the first exhaust flow path 1302 and the alternative exhaust flow path 1303, thereby controlling the route taken by the exhaust gases flowing through the exhaust system 1301.

[0173] Numerous modifications may be made to any of the above examples without departing from the scope of the present invention as defined in the appended claims. For example, the turbocharger included in each of the above-described embodiments may be replaced with a different type of charging device, such as a conventional mechanical supercharger, or alternatively, it may be omitted altogether. Other modifications and variations will be apparent to those skilled in the art.

Claims

[1] An intake system (403, 503, 1003) for delivering air to an internal combustion engine of an automobile, the intake system (403, 503, 1003) comprising two electric superchargers (406, 407) arranged to compress air flowing through the intake system (403, 503, 1003) prior to delivery to the internal combustion engine in use, wherein the electric superchargers (406, 407) are charging devices in which the compressor is driven only by an electric motor, wherein the two electric superchargers (406, 407) are provided in a configurable arrangement which, during use of the intake system (403, 503, 1003), can be selectively switched between a series configuration in which the two electric superchargers (406, 407) are arranged in series with each other, and a parallel configuration in which the two electric superchargers (406, 407) are arranged in parallel with each other, wherein the intake system (403, 503, 1003) further comprises an additional charging device. [2] Intake system (403, 503, 1003) according to claim 1, wherein the two electric superchargers (406, 407) are arranged in series with the additional charging device. [3] Intake system (403, 503, 1003) according to claim 1, wherein the two electric superchargers (406, 407) are arranged in parallel to the additional charging device. [4] Intake system (403, 503, 1003) according to claims 1 to 3, wherein the intake system (403, 503, 1003) comprises a first flow path (408a, 508a, 1008a, 1108a, 1208b) for discharging air from an outlet of a first of the two electric superchargers (406, 407) to an inlet of a second of the two electric superchargers (406, 407) when the two electric superchargers (406, 407) are operated in the series configuration, a second flow path (408b, 508b, 1008b) for discharging air from the outlet of the first electric supercharger (406, 407) and bypassing the second electric supercharger (406, 407) when the two electric superchargers (406, 407) are operated in the parallel configuration, and a third flow path (408c, 508c, 1008c) for bypassing the first electric supercharger (406, 407) and delivering air to the inlet of the second electric supercharger (406, 407) when the two electric superchargers (406,407) operated in parallel configuration. [5] Intake system (403, 503, 1003) according to claim 4, wherein the first flow path (408a, 508a, 1008a, 1108a, 1208b) is provided with a first valve element (513a, 1053a, 1305) that can be opened to allow air to flow from the first electric supercharger (406, 407) to the second electric supercharger (406, 407), the second flow path (408b, 508b, 1008b, 1108a) is provided with a second valve element (1306) that can be opened to allow air to flow from the first electric supercharger (406, 407) and bypass the second electric supercharger (406, 407), and wherein the third Flow path (408c, 508c, 1008c) is provided with a third valve element (513a-c, 1053a-c) which can be opened to allow air to bypass the first electric supercharger (406, 407) and flow to the second electric supercharger (406, 407). [6] The intake system (403, 503, 1003) of claim 5, wherein the second and third valve elements (513a-c, 1053a-c) are arranged to be operated in phase with each other, and wherein the first valve element (513a, 1053a, 1305) is arranged to be operated out of phase with the second (1306) and third valve elements. [7] An intake system (403, 503, 1003) according to claim 5 or 6, wherein two or more of the first, second and third valve elements are arranged to be operated together by a common actuator (535, 1055, 1155, 1255, 1307). [8] Intake system (403, 503, 1003) according to one of claims 5 to 7, wherein two or more of the first, second and third valve elements are coupled to a common shaft (534, 1054, 1154, 1254, 1308). [9] Intake system (403, 503, 1003) according to one of claims 5 to 8, wherein two or more of the first, second and third valve elements (513a, 513b, 513c) are provided within a common housing. [10] Intake system (403, 503, 1003) according to one of the preceding claims, wherein the intake system (403, 503, 1003) further comprises a common charge cooling device (9) arranged downstream of both electric superchargers for cooling air that has flowed through one or both of the two electric superchargers (406, 407). [11] The intake system (403, 503, 1003) of any preceding claim, wherein the intake system (403, 503, 1003) further comprises a bypass conduit (12, 112a, 112b, 212, 412, 1012) operable to selectively bypass at least one of the two electric superchargers (406, 407). [12] The intake system (403, 503, 1003) of claim 11, wherein the bypass line (12, 112a, 112b, 212, 412, 1012) is operable to selectively bypass both of the two electric superchargers (406, 407). [13] Intake system (403, 503, 1003) according to one of the preceding claims, wherein the two electric superchargers (406, 407) have the same connected load. [14] Internal combustion engine of an automobile equipped with an intake system (403, 503, 1003) according to one of the preceding claims. [15] A vehicle comprising an internal combustion engine according to claim 14. [16] A vehicle according to claim 15, wherein the vehicle comprises a control module (21, 421, 1021) arranged to control the operation of the two electric superchargers (406, 407). [17] A vehicle according to claim 16, wherein the control module (21, 421, 1021) is arranged to provide the same power to each of the two electric superchargers (406, 407) in use. [18] A method of operating an intake system (403, 503, 1003) of an internal combustion engine of an automobile, the method comprising delivering air to the internal combustion engine through the intake system (403, 503, 1003); passing air through two electric superchargers (406, 407) provided in the intake system (403, 503, 1003); wherein the electric superchargers (406, 407) are charging devices in which the compressor is driven only by an electric motor, and using the two electric superchargers (406, 407) to compress air flowing through the intake system (403, 503, 1003) before delivery to the internal combustion engine, wherein the method comprises switching the two electric superchargers (406, 407) between a series configuration in which the two electric superchargers (406, 407) are arranged in series with each other and a parallel configuration in which the two electric superchargers (406, 407) are arranged in parallel with each other during use of the engine (401, 501, 1001); wherein the intake system (403, 503, 1003) further comprises an additional charging device.

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