The invention relates to a supercharging system for an internal combustion piston engine, wherein the supercharging system comprising a turbocharger unit having a compressor part and a turbine part mechanically connected with each other, an exhaust gas system connecting the turbine part of the turbocharger unit with the engine, an inlet air system connecting the compressor part of the turbocharger unit with the engine, a waste gate arrangement having an upstream end in flow connection with the inlet air system downstream of the compressor part of the turbocharger unit, and a valve configured to regulate the flow of gas in the waste gate arrangement, wherein the valve comprises a movable valve member configured to restrict flow of gas through the valve and a flow control unit configured to move the movable valve member as defined in the preamble of independent claim 1.

The invention relates also to a method of operating a waste gate arrangement in an internal combustion piston engine having a supercharging system comprising a turbocharger unit comprising a compressor part and a turbine part mechanically connected with each other, an exhaust gas system connecting the turbine part of the turbocharger unit with the engine, an inlet air system connecting the compressor part of the turbocharger unit with the engine, wherein the waste gate arrangement having an upstream end in flow connection with the inlet air system downstream of the compressor part of the turbocharger unit, and having a valve configured to regulate the flow of gas in the waste gate arrangement, wherein the valve comprises a movable valve member configured to restrict flow of gas through the valve and a flow control unit configured to move the movable valve member as defined in the preamble of independent claim 17.

Cold air can cause problems in supercharging systems. The reason for this is that cold air is dense, which means that if cold air is fed into a supercharging system and is compressed by the compressor part of the turbocharger unit of the supercharging system, the pressure that is produced by the compressor part of the turbocharger unit on the downstream side of the compressor part of the turbocharger unit can exceed the pressure the compressor part of the turbocharger unit is able to produce. The result of this can be damages on the compressor part of the turbocharger unit. Objective of the invention

The object of the invention is to provide a solution to the problem. As electrical components are not reliable in cold conditions, a requirement is that the problem is solved without using electrical components. Short description of the invention

The supercharging system for an internal combustion piston engine is characterized by the definitions of independent claim 1.

Preferred embodiments of the supercharging system are defined in the dependent claims 2 to 16.

The method of operating a waste gate arrangement in an internal combustion piston engine is characterized by the definitions of independent claim 17.

Preferred embodiments of the method are defined in the dependent claims 18 to 26.

The invention is based on controlling the flow control unit of the valve of the waste gate arrangement mechanically in response to the temperature sensed by a thermally-responsive actuator. As the thermally-responsive actuator is mechanically connected to the flow control unit of the valve if the waste gate arrangement, no electrical devices are needed. The thermally- responsive actuator can for example be configured to sense the temperature of at least one of ambient air surrounding a housing where the internal combustion piston engine having the supercharging system is arranged, or air flowing in the inlet air system upstream of the compressor part of the turbocharger unit.

List of figures

In the following the invention will described in more detail by referring to the figures, which

Figure 1 shows a flow diagram of a first embodiment,

Figure 2 shows a flow diagram of a second embodiment,

Figure 3 shows a flow diagram of a third embodiment,

Figure 4 shows a flow diagram of a fourth embodiment,

Figure 5 shows a flow diagram of a fifth embodiment,

Figure 6 shows a flow diagram of a sixth embodiment,

Figure 7 shows a flow diagram of a seventh embodiment,

Figure 8 shows a flow diagram of an eight embodiment,

Figure 9 shows a flow diagram of a ninth embodiment.

Figure 10 shows a flow diagram of a tenth embodiment,

Figure 11 shows a flow diagram of an eleventh embodiment, and

Figure 12 shows a thermally-responsive actuator that can be used in the system and in the method. Detailed description of the invention

The figures 1 to 11 shows some embodiments of the supercharging system.

First the supercharging system for an internal combustion piston engine 1, and some embodiments and variants of the supercharging system will be described in greater detail. The supercharging system comprises a turbocharger unit 2 having a compressor part 3 and a turbine part 4 mechanically connected with each other.

The supercharging system comprises an exhaust gas system 5 connecting the turbine part 4 of the turbocharger unit 2 with the engine 1.

The supercharging system comprises an inlet air system 6 connecting the compressor part

3 of the turbocharger unit 2 with the engine 1.

The supercharging system comprises a waste gate arrangement 7 having an upstream end 8 in flow connection with the inlet air system 6 downstream of the compressor part 3 of the turbocharger unit 2.

The supercharging system comprises a valve 9 configured to regulate the flow of gas in the waste gate arrangement 7.

The valve 9 comprises a movable valve member 10 configured to restrict flow of gas through the valve 9 and a flow control unit 11 configured to move the movable valve member.

The flow control unit 11 of the valve 9 of the waste gate arrangement 7 is mechanically connected to a thermally-responsive actuator 12 so that the thermally-responsive actuator 12 is configured to control the flow control unit 11 of the valve 9 in response to temperatures sensed by the thermally-responsive actuator 12.

Figures 1 to 11 shows for clarity reasons additionally an exhaust manifold 20 of the internal combustion piston engine 1, an inlet manifold 21 of the internal combustion piston engine 1, and cylinders 22 of the internal combustion piston engine 1. The function of an internal combustion engine is known in the art.

The thermally-responsive actuator 12 can comprise a hollow tube member 13, such as a hollow rigid housing or a capillary, having a cavity 24 filled with a thermally expansive substance 25 that is configured to expand and contract in response to changes in temperature of the thermally expansive substance 25, wherein the thermally expansive substance 25 being configured to act upon an actuator unit 14 such as a piston member that is in contact with the thermally expansive substance 25 and that is in contact with the flow control unit 11 of the valve 9. Figure 12 show a thermally-responsive actuator 12 of this type. The thermally-responsive actuator 12 can comprise a spring means (not shown in the figures) that is configured to be loaded with spring energy as the thermally expansive substance 25 expands and acts upon the actuator unit 14, whereby the spring energy loaded to the spring means is configured to act upon the actuator unit 14 as the thermally expansive substance 25 contracts. In such way, the spring means can be used to bring the actuator unit 14 for example to a retracted position as the thermally expansive substance 25 contracts.

Alternatively, the thermally-responsive actuator 12 can comprise at least one bimetallic member having an outer form that is configured to vary in response to changes in temperature of said at least one bimetallic member, wherein said at least one bimetallic member being configured to act upon an actuator unit 14 such as a piston member that is in contact with said at least one bimetallic member and that is in contact with the flow control unit 11 of the valve 9.

The thermally-responsive actuator 12 is preferably, but not necessarily, thermally insulated except for an end 17 of the thermally-responsive actuator 12.

The supercharging system can, as shown in figures 2, 4, 6, 8, 10 and 11, be provided at an internal combustion piston engine 1 arranged in a housing 15, and by an upstream end 16 of the inlet air system 6 can be in flow connection with ambient air surrounding the housing 15.

If the supercharging system is provided at an internal combustion piston engine 1 arranged in a housing 15, and having an upstream end 16 of the inlet air system 6 in flow connection with ambient air surrounding the housing 15, the thermally-responsive actuator 12 can be exposed or have and end 17 exposed to the ambient air surrounding the housing 15.

The thermally-responsive actuator 12 can be exposed to or the thermally-responsive actuator 12 can have an end 17 exposed to gas flowing in the inlet air system 6 upstream of the compressor part 3 of the turbocharger unit 2.

If the supercharging system is provided at an internal combustion piston engine 1 arranged in a housing 15, and having an upstream end 16 of the inlet air system 6 in flow connection with ambient air surrounding the housing 15, the thermally-responsive actuator 12 can be exposed or the thermally-responsive actuator 12 can have an end 17 exposed to gas flowing in the inlet air system 6 upstream of the compressor part 3 of the turbocharger unit 2.

The waste gate arrangement 7 can, as shown in figures 3 to 11, have a downstream end 18 in flow connection with the inlet air system 6 upstream of the compressor part 3 of the turbocharger unit 2. An advantage of this is that thermal energy of the gas i.e. the inlet air from the waste gate arrangement 7 heats fresh inlet air coming from the upstream end 16 if the inlet air system 6 prior the compressor part 3 of the turbocharger unit 2. As a result of this, the air fed to the compressor part 3 of the turbocharger unit 2 will be less dense. Alternatively, as shown in figures 1 and 2, the waste gate arrangement 7 can have a downstream end 18 configured to discharge gas from the waste gate arrangement 7 on the outside of the inlet air system 6.

The inlet air system 6 can, as shown in figures 5 to 11, comprise a charger air cooler 19 downstream of the compressor part 3 of the turbocharger unit 2. The upstream end 8 of the waste gate arrangement 7 can, as shown in figures 9 to 11, be in flow connection with the inlet air system 6 via the charger air cooler. The upstream end 8 of the waste gate arrangement 7 can, as shown in figures 7 and 8, be in flow connection with the inlet air system 6 upstream of the charger air cooler. The upstream end 8 of the waste gate arrangement 7 can, as shown in figures 5 and 6, be in flow connection with the inlet air system 6 downstream of the charger air cooler.

The flow control unit 11 of the valve 9 can be pneumatically assisted or driven and be fed by air from a pneumatic system 23. In such case, the thermally-responsive actuator 12 such as an actuator unit 14 of the thermally-responsive actuator 12, can be configured to control the flow control unit 11 of the valve 9 by controlling the feeding of air from the pneumatic system 23 to the flow control unit 11 of the valve 9. The flow control unit 11 of the valve 9 can be configured to move the movable valve member 10 selectively to a fully open position or to a fully closed position. Alternatively, the flow control unit 11 of the valve 9 can be configured to move the movable valve member 10 between a fully open position and a fully closed position and to positions between said fully open position and said fully closed position.

The supercharging system is preferably, but not necessarily, provided with a manual bypass arrangement 26 with a manual valve. With a such manual by-pass arrangement, pressure can manually be released from the downstream side of the compressor part 3 of the turbocharging unit of the supercharging system.

Next the method of operating a waste gate arrangement 7 in an internal combustion piston engine 1 and some embodiments will be described in greater detail.

The internal combustion piston engine 1 has a supercharging system comprising a turbocharger unit 2 having a compressor part 3 and a turbine part 4 mechanically connected with each other, an exhaust gas system 5 connecting the turbine part 4 of the turbocharger unit 2 with the engine 1, an inlet air system 6 connecting the compressor part 3 of the turbocharger unit 2 with the engine 1, wherein the waste gate arrangement 7 having an upstream end 8 in flow connection with the inlet air system 6 downstream of the compressor part 3 of the turbocharger unit 2, and having a valve 9 configured to regulate the flow of gas in the waste gate arrangement 7, wherein the valve 9 comprises a movable valve member 10 configured to restrict flow of gas through the valve 9 and a flow control unit 11 configured to move the movable valve member.

The method comprises providing a thermally-responsive actuator 12, mechanically connecting the flow control unit 11 of the valve 9 of the waste gate arrangement 7 to the thermally-responsive actuator 12, and controlling the flow control unit 11 of the valve 9 in response to temperatures sensed by the thermally-responsive actuator 12.

In some embodiments of the method, the supercharging system is provided at an internal combustion piston engine 1 arranged in a housing 15 so that an upstream end 16 of the inlet air system 6 being in flow connection with ambient air surrounding the housing 15. In such cases, the method can comprise arranging the thermally-responsive actuator 12 or arranging an end of the thermally-responsive actuator 12 exposed to the ambient air surrounding the housing 15.

The method can comprise arranging the thermally-responsive actuator 12 exposed or arranging an end of the thermally-responsive actuator 12 to gas flowing in the inlet air system 6 upstream of the compressor part 3 of the turbocharger unit 2.

The method can comprise providing a thermally-responsive actuator 12 comprising a hollow tube member 13, such as a hollow rigid housing or a capillary, having a cavity 24 filled with a thermally expansive substance 25 that is configured to expand and contract in response to changes in temperature of the thermally expansive substance 25, wherein the thermally expansive substance 25 being configured to act upon an actuator unit 14 such as a piston member that is in contact with the thermally expansive substance 25, mechanically connecting the actuator unit 14 with the flow control unit of the valve 9, and controlling the flow control unit 11 of the valve 9 with the actuator unit 14 of the thermally-responsive actuator 12. The thermally- responsive actuator 12 can comprise a spring means (not shown in the figures) that is configured to be loaded with spring energy as the thermally expansive substance 25 expands and acts upon the actuator unit 14, whereby the spring energy loaded to the spring means is configured to act upon the actuator unit 14 as the thermally expansive substance 25 contracts. In such way, the spring means can be used to bring the actuator unit 14 for example to a retracted position as the thermally expansive substance 25 contracts.

The method can comprise providing a thermally-responsive actuator 12 comprising at least one bimetallic member having an outer form that is configured to vary in response to changes in temperature of said at least one bimetallic member, wherein said at least one bimetallic member being configured to act upon an actuator unit 14 such as a piston member that is in contact with said at least one bimetallic member, mechanically connecting the actuator unit 14 with the flow control unit of the valve 9, and controlling the flow control unit 11 of the valve 9 with the actuator unit 14 of thermally-responsive actuator 12.

In some embodiments of the method, the supercharging system is provided at an internal combustion piston engine 1 arranged in a housing 15 so that an upstream end 16 of the inlet air system 6 being in flow connection with ambient air surrounding the housing 15. In such cases, the method can comprise arranging the thermally-responsive actuator 12 or an end 17 of the thermally-responsive actuator 12 exposed to the ambient air surrounding the housing 15. The method can comprise arranging the thermally-responsive actuator 12 or arranging an end 17 of the thermally-responsive actuator 12 exposed to gas flowing in the inlet air system 6 upstream of the compressor part 3 of the turbocharger unit 2. The method comprises preferably, but not necessarily, thermally insulating the thermally-responsive actuator 12 except for said end.

The method comprises preferably, but not necessarily, as shown in figures 3 to 11, connecting a downstream end 18 of the waste gate arrangement 7 in flow connection with the inlet air system 6 upstream of the compressor part 3 of the turbocharger unit 2, and feeding air from the waste gate arrangement 7 into the inlet air system 6 upstream of the compressor part 3 of the turbocharger unit 2. An advantage of this is that thermal energy of the gas i.e. the inlet air from the waste gate arrangement 7 heats fresh inlet air coming from the upstream end 16 if the inlet air system 6 prior the compressor part 3 of the turbocharger unit 2. As a result of this, the air fed to the compressor part 3 of the turbocharger unit 2 will be less dense. Alternatively, the method can, as shown in figures 1 and 2, comprise discharging air from the waste gate arrangement 7 to the outside of the inlet air system 6.

The can comprise moving the movable valve member 10 with the flow control unit 11 of the valve 9 selectively to a fully open position or to a fully closed position in response to the temperatures sensed by the thermally-responsive actuator 12.

The method can comprise moving the movable valve member 10 with the flow control unit 11 of the valve 9 between a fully open position and a fully closed position and to positions between said fully open position and said fully closed position in response to the temperatures sensed by the thermally-responsive actuator 12.

It is apparent to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are therefore not restricted to the above examples, but they may vary within the scope of the claims.