Pressure Fluid Handling Systems

Abstract

The present invention relates to a pressure fluid treatment system (37), comprising a closed pressure fluid circuit, wherein the pressure fluid circuit comprises a compressor (31) and a pressure tank (38) connected in series with each other, and a primary pressure fluid path (30) extending from the compressor (31) to the pressure tank (38) and a secondary pressure fluid path (32) extending from the pressure tank (38) to the compressor (31), and the pressure fluid treatment system (37) further comprises a pressure fluid accumulator (40) connected to the pressure fluid circuit via a first pressure fluid accumulator conduit (41). The pressure fluid treatment system is characterized in that the first pressure fluid accumulator conduit (41) comprises a pump (42) configured to pump pressure fluid from the pressure fluid circuit to the pressure fluid accumulator (40) to reduce the pressure level in the pressure fluid circuit, and the pressure fluid treatment system (37) comprises at least one controllable component, the at least one controllable component being used to return pressure fluid from the pressure fluid accumulator (40) to the pressure fluid circuit to increase the pressure level in the pressure fluid circuit.

Description

Technical Field

[0001] The present invention generally relates to a pressure fluid handling system comprising a closed pressure fluid circuit having a primary side (high pressure side) and a secondary side (low pressure side), wherein the pressure fluid handling system comprises an active device that performs a useful task and is intended to provide a time-varying / variable capacity. Thus, the pressure fluid handling system is configured to provide a variable pressure fluid flow in the pressure fluid circuit and / or a variable pressure ratio between the primary side and the secondary side and / or variable pressure levels in the primary side and the secondary side to meet the changing capacity requirements of the active device of the pressure fluid handling system.

[0002] The invention is suitable for realizing so-called HVAC applications (i.e. heating, ventilation and air conditioning), for indoor, especially vehicle environmental comfort, for driving / operating pneumatic devices in internal combustion engines (especially internal combustion engines of the camless piston engine type, also referred to as the term / concept "engine with free valves"), for driving / operating pneumatic devices in pneumatic machines / tools, etc. The internal combustion engines are suitable for powering vehicles, such as cars or trucks, boats, etc., or for powering machines, such as generator sets or the like.

[0003] The present invention specifically relates to a pressure fluid processing system, which includes a closed pressure fluid circuit, wherein the pressure fluid circuit includes a compressor and a pressure tank connected in series with each other, and a primary pressure fluid path extending from the compressor to the pressure tank and a secondary pressure fluid path extending from the pressure tank to the compressor. The pressure fluid processing system also includes a pressure fluid accumulator, which is connected to the pressure fluid circuit via a first pressure fluid accumulator conduit, and the present invention also relates to a method for controlling such a pressure fluid processing system.

[0004] In a second aspect, the invention relates to an internal combustion engine comprising such a pressurized fluid handling system. Background Art

[0005] The invention is based on the fact that many known applications in various technical fields utilize pressure fluid flow in a closed pressure fluid circuit and utilize the pressure difference between the primary side and the secondary side of the closed pressure fluid circuit to operate / drive devices or equipment to perform useful tasks.

[0006] For example, cars and trucks have an air conditioning system that includes or consists of a pressure fluid handling system, wherein the pressure fluid flow in a closed pressure fluid circuit and the pressure difference between the primary side and the secondary side are used to achieve conversion between liquid and gas / vapor of the pressure fluid to heat or cool the air in the vehicle coupe.

[0007] For example, internal combustion engines and pneumatic machines / tools having pneumatic devices / components utilize pressurized fluid flow in a closed pressure fluid circuit and a pressure difference between the primary side and the secondary side to operate / drive the pneumatic device, such as to move an element back and forth or to rotate an element.

[0008] In current HVAC applications, especially air conditioning systems in cars and trucks, where the compressor of the pressure fluid handling system is driven by the internal combustion engine, the operating speed of the compressor is more or less constant during steady-state driving of the vehicle and when the internal combustion engine is idling, since the engine speed is constant. In this case, the capacity of the fixed displacement compressor (or more precisely the capacity of the pressure fluid handling system) is regulated by using an adjustable expansion valve. In such a system, the pressure fluid flow will increase through the expansion valve to match the increased capacity demand, so the pressure level on the low-pressure side will increase while the pressure level on the high-pressure side will decrease. Therefore, when the demand for cold air is greatest, i.e. when the car is parked in the sun and when returning to the car on a hot day, the air conditioning system will have the worst performance when the engine speed and the compressor speed are low. Therefore, the air conditioning system must be sized to cope with such conditions and is therefore oversized in most cases. The same conditions apply to electric compressors with fixed operating speeds in other HVAC applications.

[0009] In existing internal combustion engines having pneumatic devices / components driven / operated by a pressure fluid handling system, the compressor of the pressure fluid handling system is driven by the internal combustion engine, and the pressure fluid flow, pressure level and pressure ratio in the system cannot change faster than the change in the operating speed of the internal combustion engine, that is, the capacity of the active device of the pressure fluid handling system to perform useful tasks depends entirely on the operating speed of the compressor, and thus depends entirely on the operating speed of the internal combustion engine.

[0010] In a camless internal combustion engine, a pressurized fluid such as a liquid or a gas is used, for example, to achieve the displacement / opening of one or more engine valves. This means that the camshaft and the associated equipment used by a conventional internal combustion engine to open the engine valves to let air into the combustion chamber and exhaust gases out of the combustion chamber, respectively, have been replaced by a less volume demanding and more controllable system.

[0011] In engines constructed for significant angular momentum output, such as high-performance automobiles, the pressure in the combustion chamber increases in proportion to the increase in angular momentum output, and the force required to open the valve actuator to open (open inwardly relative to the combustion chamber) the engine valve therefore also increases in proportion to the increased angular momentum output. At high operating speeds of the internal combustion engine, i.e., high revolutions, such as 6-8000rpm, it is also necessary to open the engine valve very quickly so that the filling of the engine cylinder with air and the discharge of exhaust gases from the engine cylinder are unrestricted. These requirements, i.e., the need for extremely fast opening at a high frequency in high-performance engines with high back pressure in the engine combustion chamber when the exhaust valve opens, require a pressure of the pressure fluid upstream of the valve actuator of up to about 8-30 bar. Downstream of the valve actuator, the pressure fluid has a lower pressure of about 3-6 bar.

[0012] At high rpm and high engine load, the pressure difference between the low-pressure side and the high-pressure side should be around 15-20 bar for correct operation of the valve actuator, and when the engine is idling, or at low rpm and low load, the pressure difference between the low-pressure side and the high-pressure side only needs to be about 2-5 bar.

[0013] In situations where rapid acceleration and / or a rapid change from low rpm and low load to high rpm and high load is required, such as when entering a busy main road or when suddenly overtaking a slow moving vehicle, the pressure level on the low pressure side and the high pressure side and the pressure level and pressure difference between the low pressure side and the high pressure side must be increased immediately to achieve the acceleration required by the driver while the pressure fluid flow must be increased. There are known compressors, especially compressors with variable displacement, which are able to achieve the required pressure level and pressure difference between the low pressure side and the high pressure side, but they are not configured to meet the requirements of immediate / instantaneous switching from low pressure level and pressure difference to high pressure level and pressure difference and / or from low pressure fluid flow to high pressure fluid flow. Therefore, such compressors (swash plates) are inefficient, while they need to be oversized and too expensive for these applications to meet the requirements. Furthermore, there is inertia in the present system from high / large pressure differential to low / small pressure differential and from the need for high-pressure fluid flow to low-pressure fluid flow, i.e., when the vehicle is operated again at low speed after a brief / temporary increase in speed / engine load, it takes some time before the pressure differential and thus the high energy consumption of the system drops to the desired level.

[0014] From US10077689 of the applicant, a pressure fluid handling system of the initially defined type is known, wherein the system comprises a pressure fluid accumulator connected to a pressure fluid circuit via a controllable valve. The key to this patent is to preserve the peak pressure of the primary pressure fluid path in the pressure fluid accumulator. Thus, the pressure fluid accumulator is activated when the pressure demand, the pressure level in the pressure fluid circuit and the operating speed of the compressor are at a maximum.

[0015] Therefore, there is a need to provide a pressurized fluid handling system that is capable of controlling / varying over time the capacity of an active device of the pressurized fluid handling system that performs a useful task independent of the operating speed of the compressor. Summary of the invention

[0016] It is an object of the present invention to obviate the above-mentioned disadvantages and drawbacks of previously known pressure fluid handling systems and to provide an improved pressure fluid handling system.

[0017] The main object of the present invention is to provide a pressure fluid handling system of the initially defined type, which is configured to provide a variable pressure fluid flow in the pressure fluid circuit and / or a variable pressure ratio between the primary side and the secondary side and / or a variable pressure level in the primary side and the secondary side to meet the constantly changing capacity requirements of the active device of the pressure fluid handling system.

[0018] Another object of the present invention is to provide a pressure fluid handling system arranged to be able to instantly increase the pressure differential between the primary (high) pressure side and the secondary (low) pressure side when there is a need to quickly increase the capacity demand of an active device of the pressure fluid handling system.

[0019] Another object of the present invention is to provide a pressure fluid handling system that can quickly change from a large pressure difference to a small pressure difference between a low pressure side and a high pressure side.

[0020] It is another object of the present invention to provide a pressurized fluid handling system wherein the pressurized fluid accumulator is activated when capacity demand is low.

[0021] Brief description of features of the present invention

[0022] According to the invention, at least the primary object is achieved by the initially defined pressure fluid treatment system and by an internal combustion engine having the features defined in the independent claims. Preferred embodiments of the invention are further defined in the dependent claims.

[0023] According to a first aspect of the present invention, there is provided a pressure fluid handling system of an initially defined type, characterized in that a first pressure fluid accumulator conduit includes a pump configured to pump pressure fluid from a pressure fluid circuit to the pressure fluid accumulator to reduce the pressure level in the pressure fluid circuit, and the pressure fluid handling system includes at least one controllable component for returning pressure fluid from the pressure fluid accumulator to the pressure fluid circuit to increase the pressure level in the pressure fluid circuit.

[0024] According to a second aspect of the present invention there is provided an internal combustion engine of the initially defined type comprising such a pressure fluid handling system.

[0025] According to a third aspect of the present invention, there is provided a method for controlling such a pressure fluid handling system.

[0026] The invention is therefore based on the recognition that, thanks to the pump and the pressure fluid accumulator, the amount / density of pressure fluid in a closed pressure fluid circuit is effectively and immediately regulated in order to match varying capacity demands from active devices of the pressure fluid handling system independently of the operating speed of the compressor.

[0027] During normal (i.e. low load) and steady-state operation, the pressure level in the pressure fluid circuit may be very low, in which case the pump delivers pressure fluid from the pressure fluid circuit to the pressure fluid accumulator and generates an elevated pressure in the pressure fluid accumulator that exceeds the highest possible pressure level in the primary pressure fluid path so that the stored pressure fluid can later be quickly supplied back to the pressure fluid circuit at high pressure to achieve an immediate pressure increase and an increased pressure differential in the primary pressure fluid path independent of the operating speed of the compressor.

[0028] According to a preferred embodiment of the invention, the pressure fluid accumulator is connected to the primary pressure fluid path of the pressure fluid circuit via a first pressure fluid accumulator conduit.Thereby, a faster reduction of the pressure level in the pressure fluid circuit will be obtained, thereby reducing energy consumption.

[0029] According to a preferred embodiment of the invention, the at least one controllable component is constituted by a first controllable valve which is configured to return pressure fluid from the pressure fluid accumulator to the primary pressure fluid path of the pressure fluid circuit. Thus, a faster increase of the pressure level and the pressure level difference in the pressure fluid circuit is obtained.

[0030] According to a preferred embodiment of the invention, the compressor is a fixed displacement scroll compressor having all the known advantages of a scroll compressor with respect to corresponding piston compressors in terms of noise, efficiency, size, etc.

[0031] According to a preferred embodiment of the invention, the at least one controllable component consists of a second controllable valve configured to return pressure fluid from the pressure fluid accumulator to the secondary pressure fluid path. Thus, an additional increase in the pressure level in the pressure fluid circuit is obtained.

[0032] Further advantages and features of the present invention become apparent from the remaining dependent claims and the following detailed description of preferred embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] A more complete understanding of the above and other features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings, in which:

[0034] Figure 1is a schematic cross-sectional side view of a portion of an internal combustion engine,

[0035] Figure 2 is a schematic cross-sectional side view of a valve actuator,

[0036] Figure 3 is a schematic perspective view of a partial section of a cylinder head.

[0037] Figure 4 is a schematic circuit diagram disclosing a basic exemplary embodiment of a pressure fluid handling system of the present invention,

[0038] Figure 5 is a schematic circuit diagram of a second exemplary embodiment of a pressure fluid processing system for controlling a pneumatic device,

[0039] Figure 6 is a schematic circuit diagram of a third exemplary embodiment of a pressure fluid handling system for controlling a pneumatic device in an internal combustion engine, and

[0040] Figure 7 is a schematic circuit diagram of a fourth exemplary embodiment of a pressure fluid handling system for an air conditioning system. DETAILED DESCRIPTION

[0041] First reference Figure 1 , which is a schematic diagram of a portion of an internal combustion engine, generally indicated at 1, comprising a pressure fluid handling system of the present invention. The internal combustion engine 1 comprises a cylinder block 2 having at least one cylinder 3. The cylinder block 2 typically comprises three, four or more cylinders 3. In the illustrated embodiment only one cylinder 3 is referenced, however it will be appreciated that in embodiments where the internal combustion engine comprises more than one cylinder, the apparatus described below with respect to the illustrated cylinder 3 preferably applies to all cylinders of the internal combustion engine 1.

[0042] Furthermore, the internal combustion engine 1 comprises a piston 4 axially movable in said cylinder 3. The fore-and-aft axial displacement movement of the piston 4 is transmitted in a conventional manner to a connecting rod 5 connected to the piston 4, which in turn is connected to a crankshaft (not shown) and drives the crankshaft in rotation.

[0043] The internal combustion engine 1 further comprises a cylinder head 6 which, together with the cylinder 3 and the piston 4, delimits a combustion chamber 7. In the combustion chamber 7, ignition of the mixture of fuel and air / gas takes place in a conventional manner and is not described further here. The cylinder head 6 comprises at least one controllable first engine valve 8, also referred to as a gas exchange valve. In the embodiment shown, the cylinder head further comprises a controllable second engine valve 9. In the embodiment shown, one engine valve constitutes an inlet valve, which is arranged to open / close the supply of air / gas to the combustion chamber 7, and the second engine valve 9 constitutes an outlet valve or exhaust valve in the embodiment shown, which is arranged to open / close the discharge of exhaust gases from the combustion chamber 7.

[0044] The internal combustion engine 1 further comprises a first valve actuator, generally indicated by 10, which is operatively connected to the first engine valve 8 and is arranged in a closed pressure fluid circuit of the internal combustion engine 1. The valve actuator 10 in turn comprises a pneumatic pressure fluid circuit having at least one inlet opening 11 for the pressure fluid and at least one outlet opening 12 for the pressure fluid. In this embodiment, the pressure fluid is a gas or a gas mixture, preferably air or nitrogen. The advantage of air is that it is easy to change the pressure fluid or supply more pressure fluid in the event of a leak in the closed pressure fluid circuit, while the advantage of nitrogen is that it lacks oxygen, which prevents oxidation of other elements.

[0045] In case the internal combustion engine 1 comprises several valve actuators, these valve actuators are arranged parallel to each other in the closed pressure fluid circuit. Each valve actuator can be operably connected to one or more engine valves, and the internal combustion engine may, for example, comprise two air inlet valves 8, which are driven together by the same valve actuator 10. However, it is preferred that each valve actuator operates one engine valve to achieve the greatest possible controllability of the operation of the internal combustion engine 1. The valve actuator 10 is an active device / component of the pressure fluid handling system, which performs a useful task, namely for moving the engine valves or other elements for a forward and backward movement. The valve actuator 10 is a pressure tank in the pressure fluid circuit in such an internal combustion engine 1 application.

[0046] The following description of an internal combustion engine will include only one engine valve and one valve actuator 10 , but it should be appreciated that the same applies to all engine valves and valve actuators unless otherwise stated.

[0047] The internal combustion engine 1 further comprises a cylinder head chamber 13, which preferably forms part of the closed pressure fluid circuit and is delimited by the cylinder head 6 and at least a first cylinder head cover 14. In the embodiment shown, the cylinder head cover 14 is divided into two halves, which can be attached to and released from the cylinder head 6 separately by bolts 15 or the like. The cylinder head chamber 13 preferably has a volume of about 1-3 liters. In an alternative embodiment, there is only one cylinder head cover 14, which delimits the cylinder head chamber 13 together with the cylinder head 6.

[0048] exist Figure 1 In the disclosed embodiment, at least one outlet opening 12 of the valve actuator 10 is in fluid communication with the cylinder head chamber 13, i.e., the pressurized fluid exiting the valve actuator 10 flows out into the cylinder head chamber 13 via the at least one outlet opening 12. In those cases where the internal combustion engine 1 comprises a plurality of valve actuators, all outlet openings of the valve actuators for pressurized fluid discharge the pressurized fluid into the same cylinder head chamber.

[0049] Preferably, the entire valve actuator 10 is arranged in the cylinder head chamber 13, and it is also preferred that the valve actuator 10 is releasably connected to the cylinder head cover 14, for example by bolts 16 or similar retaining means. In this embodiment, the valve actuator 10 is accordingly "suspended" in the cylinder head cover 14 without contacting the cylinder head 6. According to other embodiments, the valve actuator 10 is also connected to the bottom of the cylinder head 6, or is only connected to the bottom of the cylinder head 6.

[0050] Reference now Figure 2 , which discloses a schematic diagram of a valve actuator 10 .

[0051] The valve actuator 10 comprises an actuator cylinder 18 and an actuator piston disc 17 defining a cylinder volume. In the disclosed embodiment, the cylinder volume is a cylinder volume that is open downwards, but it is also conceivable that the lower part of the cylinder volume has an opening in the radial direction. The actuator piston disc 17 divides the cylinder volume into a first upper part 19 and a second lower part 20 and is axially movable in the actuator cylinder 18. The actuator piston disc 17 forms part of an actuator piston, which is generally indicated by 21, which is arranged to contact and drive the first engine valve 8. The actuator piston 21 may further comprise means 22 for eliminating play in the axial direction relative to the first engine valve 8. The play eliminating means 22 are preferably hydraulic and ensure that when the actuator piston disc 17 is in its top dead centre position, the actuator piston 21 remains in contact with the first engine valve 8 when the first engine valve is closed, in order to correct assembly tolerances, thermal expansion, etc. Therefore, the axial length of the actuator piston 21 is adjusted by the play eliminating device 22 .

[0052] The second part 20 of the cylinder volume of the valve actuator 10 is in fluid communication with said cylinder head chamber 13. In this way, it is ensured that when the actuator piston 21 is in the top dead center position, the same pressure acts on the actuator piston disc 17 from the first part 19 of the cylinder volume and from the second part 20 of the cylinder volume, respectively. Therefore, the seal between the actuator piston disc 17 and the actuator cylinder 18 is not critical, but some leakage can be allowed to minimize the displacement resistance of the actuator piston disc 17, and in the rest position, the actuator piston disc 17 is not affected by changes in the pressure level in the cylinder head chamber 13.

[0053] The valve actuator 10 comprises a controllable inlet valve 23 arranged to open / close the inlet opening 11, a controllable outlet valve 24 arranged to open / close the outlet opening 12, a hydraulic circuit generally indicated at 25, which in turn comprises a check valve 26 arranged to allow filling of the hydraulic circuit 25 and a controllable drain valve 27 arranged to control the draining of the hydraulic circuit 25. It should be noted that the valves in the valve actuator 10 are schematically depicted and can be constituted, for example, by slide valves, seat valves, etc. In addition, several of the above-mentioned controllable valves can be constituted by a single body. Each valve can also be directly or indirectly electrically controlled. Direct electrical control means that the position of the valve is directly controlled by, for example, an electromagnetic device, and indirect electrical control means that the position of the valve is controlled by a pressure fluid, which in turn is controlled by, for example, an electromagnetic device.

[0054] In order to achieve the downward movement of the actuator piston disc 17 to open the engine valve, the inlet valve 23 is opened to allow the pressure fluid with high pressure to be filled in the upper part 19 of the cylinder volume. When the actuator piston 21 moves downward, the non-return valve 26 of the hydraulic circuit 25 opens, whereupon the hydraulic fluid is sucked in and replaces the volume left by the actuator piston 21. Thereafter, the inlet valve 23 closes and allows the pressure fluid that has entered the upper part 19 of the cylinder volume to expand, whereupon the actuator piston disc 17 continues to move downward. The actuator piston 21 stops when the pressure fluid in the upper part 19 of the cylinder volume cannot move the actuator piston disc 17 further, i.e. when the pressure on the lower side of the actuator piston disc 17 and the return spring 28 of the engine valve is as high as the pressure on the upper side of the actuator piston disc 17. It should be noted that the actuator piston 21 also has some inertia, so that the actuator piston 21 exceeds the position of force balance. By keeping the drain valve 27 of the hydraulic circuit 25 closed while the non-return valve 26 of the hydraulic circuit 25 is automatically closed, the actuator piston 21 is held (locked) in its lower position for a desired amount of time. To achieve the return movement, the outlet valve 24 is opened to allow the pressure fluid to be discharged from the upper part 19 of the cylinder volume, and in addition, the drain valve 27 of the hydraulic circuit 25 is opened, whereupon the actuator piston 21 moves upwards when the hydraulic liquid is discharged / exhausted from the hydraulic circuit 25, and at the same time, the pressure fluid is discharged / exhausted from the upper part 19 of the cylinder volume via the outlet opening 12 to the cylinder head chamber 13.

[0055] Now the main reference Figure 3 , which shows a partial cross-sectional schematic perspective view of the cylinder head 6 and components of the pressure fluid handling system, etc.

[0056] The cylinder head cover 14 comprises a pressure fluid manifold 29 which is connected to at least one inlet opening 11 of the valve actuator 10. The pressure fluid manifold 29 extends along the axial length of the cylinder head cover 14. The pressure fluid manifold 29 forms part of a primary pressure fluid path 30 extending from a compressor 31 to at least one inlet opening 11 of the valve actuator 10. The compressor 31 is arranged to supply a flow of pressure fluid under high pressure to the valve actuator. In addition, a secondary pressure fluid path 32 (see also Figure 1 ) extends from the valve actuator 10 via the cylinder head chamber 13 to the compressor 31. The compressor 31 is part of both the primary pressure fluid path 30 and the secondary pressure fluid path 32.

[0057] The volume of the primary pressure fluid path 30 on the high-pressure side should be kept as small as possible so that the temperature of the pressure fluid will drop as little as possible from the compressor 31 to the valve actuator 10. On the other hand, the volume of the secondary pressure fluid path 32 on the low-pressure side, including the cylinder head chamber 13, should be larger than the volume of the primary pressure fluid path 30 so that the pressure ratio between the low-pressure side and the high-pressure side is affected as little as possible when the compressor 31 draws pressure fluid from the low-pressure side. Preferably, the volume of the cylinder head chamber 13 and the secondary pressure fluid path 32 is equal to or greater than four times the volume of the primary pressure fluid path 30, and preferably equal to or less than ten times the volume of the primary pressure fluid path 30.

[0058] The compressor 31 is preferably a fixed displacement compressor, and the compressor 31 is usually driven by the crankshaft of the internal combustion engine 1. At high speed and high load, the pressure fluid in the primary pressure fluid path 30 needs a higher pressure, and at low speed and low load, the pressure fluid in the primary pressure fluid path 30 needs a lower pressure. The pressure difference between the high-pressure side and the low-pressure side is about 10-20 bar at high speed and high load, and about 2-6 bar at low speed and low load. The compressor 31 is preferably a scroll compressor type driven by the crankshaft of the internal combustion engine 1.

[0059] The pressure level on the high-pressure side is approximately 5-25 bar in order to open the inward-opening engine valves with sufficient speed in the presence of high back pressure in the combustion chamber, while the pressure level on the low-pressure side is approximately 1-8 bar.

[0060] The cylinder head cover 14 further comprises a hydraulic liquid manifold 33, which is connected to an inlet opening 34 of said hydraulic circuit 25 of the valve actuator 10. The hydraulic liquid manifold 33 extends along the axial length of the cylinder head cover 14, parallel to the pressure fluid manifold 29. A pump 35 or the like is arranged to supply pressurized hydraulic liquid to the hydraulic liquid manifold 33 via a conduit 36. The hydraulic liquid will accumulate at the bottom of the cylinder head chamber 13, and the pump 35 will supply pressurized hydraulic liquid to the conduit 36 ​​from the cylinder head chamber 13 directly or indirectly via a tank / reservoir of the internal combustion engine 1 using the accumulated hydraulic liquid. The cylinder head cover 14 further comprises all necessary electrical infrastructure (not shown) for controlling the first valve actuator 10, various sensors, etc.

[0061] Reference now Figure 4 , which schematically illustrates a basic embodiment of a pressure fluid handling system 37 of the present invention that is versatile for a number of different applications.

[0062] exist Figure 4 In the figure, the pressure fluid processing system 37 includes a closed / annular pressure fluid circuit, which includes a compressor 31 arranged on the right side, a primary pressure fluid path 30 (high pressure side) arranged at the upper edge, a pressure tank 38 arranged on the left side, and a secondary pressure fluid path 32 (low pressure side) arranged at the lower edge, which are connected in series with each other. The primary pressure fluid path 30 extends from the compressor 31, that is, from the compression space of the compressor 31, to the pressure tank 38. The secondary pressure fluid path 32 extends from the pressure tank 38 to the compressor 31, that is, to the compression space of the compressor 31. Therefore, the pressure fluid is Figure 4 The closed pressure fluid circuit is also referred to as an operating circuit / loop. The pressure fluid handling system 37 comprises a pressure fluid accumulator 40 / pressure fluid accumulator tank, which is connected to the pressure fluid circuit via a first pressure fluid accumulator conduit 41.

[0063] An important point of the present invention, i.e., the pressure fluid handling system 37, is that the first pressure fluid accumulator conduit 41 includes a pump 42 configured to pump pressure fluid from the pressure fluid circuit to the pressure fluid accumulator 40 to reduce the pressure level in the pressure fluid circuit when the capacity demand is low. It is also important that the pressure fluid handling system 37 includes at least one controllable component for returning pressure fluid from the pressure fluid accumulator 40 to the pressure fluid circuit to increase the pressure level in the pressure fluid circuit when the capacity demand is high. When the pump 42 removes pressure fluid from the pressure fluid circuit, the density / amount of pressure fluid remaining in the pressure fluid circuit will decrease, thereby reducing the pressure level in the pressure fluid circuit. When the pressure fluid returns to the pressure fluid circuit, the density / amount of pressure fluid present in the pressure fluid circuit will increase, thereby increasing the pressure level in the pressure fluid circuit.

[0064] The pump 42 is preferably constituted by an electric pump or a pump driven by or in parallel with the compressor 31, i.e. in internal combustion engine applications, both the pump 42 and the compressor 31 can be driven by the crankshaft of the internal combustion engine 1. The pump 42 should be configured to operate in an on / off mode, and when the pump 42 is activated / turned on, the operating speed of the pump 42 is constant or variable. The pump 42 may include an internal or supplementary check valve so that the pressure level in the pressure fluid accumulator 40 is maintained when the pump 42 is deactivated.

[0065] according to Figure 4 In the basic embodiment shown, the pressure fluid accumulator 40 is connected to the primary pressure fluid path 30 of the pressure fluid circuit via a first pressure fluid accumulator conduit 41. The density of the pressure fluid in the primary pressure fluid path 30 is higher than the density in the secondary pressure fluid path 32. Therefore, when the pump 42 is operated and removes the pressure fluid from the pressure fluid circuit, the removal of the pressure fluid is more efficient / faster when the pump 42 is operably connected to the primary pressure fluid path 30 than when it is connected to the secondary pressure fluid path 32.

[0066] according to Figure 4 In the basic embodiment shown, the at least one controllable component is constituted by a first controllable valve 43, which is configured to return the pressure fluid from the pressure fluid accumulator 40 to the pressure fluid circuit. Preferably, the first controllable valve 43 is configured to return the pressure fluid from the pressure fluid accumulator 40 to the primary pressure fluid path 30 of the pressure fluid circuit. According to one embodiment, the first controllable valve 43 is configured to return the pressure fluid from the pressure fluid accumulator 40 to the compressor 31, that is, to the compression chamber of the compressor 31, when the fluid communication between the compression chamber of the compressor 31 and the secondary pressure fluid path 32 ends and before the compression chamber is fluidly connected to the primary pressure fluid path 30.

[0067] In case there is a need for a rapid pressure increase from a low pressure level to a high pressure level in the primary pressure fluid path 30 (high pressure side), i.e. in case of an increased capacity demand from the pressure fluid handling system 37, for example as a response to the accelerator pedal being depressed in the vehicle and / or the rapid increase in the number of revolutions of the internal combustion engine or the increase / increase in air conditioning demand or the acceleration operation of a pneumatic machine / tool, etc., the first controllable valve 43 opens in order to quickly return the pressure fluid from the pressure fluid accumulator 40 to the pressure fluid circuit. Figure 4According to the basic embodiment disclosed in FIG. 4 , the pressure fluid in the pressure fluid accumulator 40 flows into the primary pressure fluid path 30 and provides an immediate pressure increase in the primary pressure fluid path 30, i.e., an immediate response to the increased capacity demand. The pressure level in the pressure fluid accumulator 40 will decrease and the pressure level in the primary pressure fluid path 30 will increase until they are equal to each other, which is done in a fraction of a second. Thereafter, the first controllable valve 43 is closed. The volume of the pressure fluid accumulator 40 is preferably in the range of three to six times greater than the volume in the primary pressure fluid path 30.

[0068] Preferably, a first pressure sensor 44 is connected to the pressure fluid accumulator 40 and a second pressure sensor 45 is connected to the primary pressure fluid path 30 to ensure that the pressure level in the pressure fluid accumulator 40 is higher than the pressure level in the primary pressure fluid path 30 before the first controllable valve 43 is opened. In the embodiment shown, a third pressure sensor 46 is also connected to the secondary pressure fluid path 32 to be able to determine the pressure ratio between the low-pressure side and the high-pressure side.

[0069] According to an alternative embodiment, the at least one controllable component is constituted by a return pump, which is configured to pump the pressure fluid from the pressure fluid accumulator 40 back to the pressure fluid circuit, preferably back to the primary pressure fluid path 30. The return pump can be used instead of the first controllable valve 43, or preferably in addition to the first controllable valve 43. When only the first controllable valve 43 is used to return the pressure fluid to the primary pressure fluid path 30, the return of the pressure fluid will stop when the pressure levels in the pressure fluid accumulator 40 and the primary pressure fluid path 30 are equal to each other. By using the return pump, more pressure fluid can be returned to the primary pressure fluid path 30, i.e. the pressure level in the primary pressure fluid path 30 can then be further increased and exceed the pressure level in the pressure fluid accumulator 40. According to one embodiment, the pump 42 and the return pump are constituted by a single bidirectional / reversible pump.

[0070] Reference now Figure 5 , which discloses a second embodiment. Only the Figure 4 The differences are related to the basic embodiments of the invention. Figure 5The embodiments disclosed in the disclosure are particularly suitable for pneumatic applications, i.e. internal combustion engine applications and pneumatic machine / tool ​​applications, in which the pressure fluid handling system 37 comprises a pneumatic closed pressure fluid circuit. In such applications, the pressure tank 38 is constituted by a pneumatic device / component, i.e. a device operated / driven by the pressure fluid flow rate and the pressure levels of the primary pressure fluid path 30 and the secondary pressure fluid path 32 and / or the pressure difference between the primary pressure fluid path 30 and the secondary pressure fluid path 32, i.e. the energy stored in the pressure fluid in the primary pressure fluid path 30 is used to obtain a mechanical movement in the pressure tank 38 (pneumatic device / component) and the pressure in the pressure fluid will be reduced thereby. Therefore, the pressure tank 38 is constituted by a pneumatic device / component, i.e., for example, the valve actuator 10 of the internal combustion engine 1 or another pneumatic device of the internal combustion engine or a pneumatic device of a pneumatic machine / tool. In such applications, the pneumatic device has a requirement for variable pressure fluid flow in the pressure fluid circuit and / or a variable pressure ratio between the primary pressure fluid path 30 and the secondary pressure fluid path 32 and / or variable pressure levels in the primary pressure fluid path 30 and the secondary pressure fluid path 32 .

[0071] In applications of the internal combustion engine 1 , the pump 42 may be located in the cylinder head chamber 13 and / or in the cylinder head cover 14 .

[0072] according to Figure 5 In the embodiment disclosed in , the at least one controllable component is further constituted by a second controllable valve 47, which is configured to return the pressure fluid from the pressure fluid accumulator 40 to the secondary pressure fluid path 32. Therefore, the pressure fluid is initially returned to the primary pressure fluid path 30 via the first controllable valve 43 until the pressure level in the pressure fluid accumulator 40 is equal to the pressure level in the primary pressure fluid path 30, after which the pressure fluid is at most returned to the secondary pressure fluid path 32 via the second controllable valve 47 until the pressure level in the pressure fluid accumulator 40 is equal to the pressure level in the secondary pressure fluid path 32. By increasing the pressure level upstream (low-pressure side) of the compressor 31, the pressure level downstream (high-pressure side) of the compressor 31 will be further increased. When the pressure fluid accumulator 40 is refilled, the first controllable valve 43 can be opened so that the pressure level in the primary pressure fluid path 30 drops immediately until the reduced pressure level in the primary pressure fluid path 30 is equal to the increased pressure level in the pressure fluid accumulator 40, after which or simultaneously the pump 42 is started to further increase the pressure level in the pressure fluid accumulator 40 and further reduce the pressure level in the primary pressure fluid path 30.

[0073] Furthermore, it is preferred that a check valve 48 is arranged in the secondary pressure fluid path 32, upstream of the position where the second controllable valve 47 is configured to return the pressure fluid to the secondary pressure fluid path 32, wherein the check valve 48 is arranged to allow flow in the direction toward the compressor 31. The returned pressure fluid is thereby prevented from having a negative impact at the outlet of the pressure groove 38 (valve actuator 10).

[0074] According to one embodiment, the second controllable valve 47 is configured to return the pressure fluid from the pressure fluid accumulator 40 to the compressor 31, that is, to the compression chamber of the compressor 31, when the fluid connection between the compression chamber of the compressor 31 and the secondary pressure fluid path 32 is ended and before the compression chamber is connected to the fluid of the primary pressure fluid path 30.

[0075] Reference now Figure 6 , which discloses a third embodiment. Only the Figure 4 and Figure 5 Except for the difference between Figure 5 In addition to the embodiments disclosed in Figure 6 The embodiment disclosed in includes a chamber 49 as part of the pressure fluid circuit. The chamber 49 is connected in series with the compressor 31 and the pressure tank 38 (pneumatic device / valve actuator 10), wherein the chamber 49 is part of the secondary pressure fluid path 32. In internal combustion engine applications, the chamber 49 is formed by the cylinder head chamber 13. The chamber 49 is preferably arranged directly downstream of the pressure tank 38. It should be noted that in Figure 4 and Figure 5 The disclosed embodiment may include a chamber 49, and Figure 6 The second controllable valve 47 may be omitted in the disclosed embodiment.

[0076] In internal combustion engine applications, the pressure fluid accumulator 40 is preferably formed by one or more internal chambers in a structural component of the cylinder head 6 , ie in a wall of the cylinder head 6 .

[0077] Reference now Figure 7 , which discloses a fourth embodiment. Only the Figure 4 The differences are related to the embodiments of the present invention. Figure 7 The embodiments disclosed in are particularly suitable for HVAC applications, i.e., air conditioning applications and similar applications, wherein the pressure fluid handling system 37 includes a pressure fluid that is primarily gas / vapor at some locations and primarily liquid at some locations, and a mixture of gas / vapor and liquid at other locations, i.e., the pressure fluid is a refrigerant.

[0078] In such applications, the pressure tank 38 is constituted by an expansion valve or a metering device / valve, i.e., a device configured to separate the primary pressure fluid path 30 from the secondary pressure fluid path 32 and configured to continuously or intermittently allow a restricted flow of pressure fluid from the primary pressure fluid path 30 to the secondary pressure fluid path 32. The pressure tank 38 is thereby used to reduce the pressure as well as the temperature of the pressure fluid.

[0079] according to Figure 7 In the embodiment disclosed in FIG. 3 , the pressure fluid processing system 37 further comprises two heat exchange units, namely a condenser 50 located in the primary pressure fluid path 30 and an evaporator 51 located in the secondary pressure fluid path 32. The pressure fluid is a refrigerant.

[0080] Therefore, when the pressure fluid leaves the compressor 31, it is a high-pressure, high-temperature gas. In the condenser 50, energy is transferred from the pressure fluid to the environment to convert the high-pressure, high-temperature gas into a high-pressure, high-temperature liquid. In the pressure tank 38, the high-pressure, high-temperature liquid is converted into a low-pressure, low-temperature liquid-gas mixture (mainly liquid). In the evaporator 51, energy is added to the pressure fluid from the environment to convert the low-pressure, low-temperature liquid-gas mixture into a low-pressure, low-temperature gas, which enters the compressor 31 again.

[0081] Preferably, the first pressure fluid accumulator conduit 41 is connected to the primary pressure fluid path 30 at a position downstream of the condenser 50, and the controllable component is configured to return the pressure fluid to the primary pressure fluid path 30 at a position downstream of the condenser 50, that is, at a position where most or all of the pressure fluid is liquid, and the pressure fluid accumulator can be composed of an expansion container.

[0082] Conceivable modifications of the invention

[0083] The invention is not limited solely to the embodiments described above and shown in the drawings, which have only illustrative and exemplary purposes. This patent application is intended to cover all modifications and variants of the preferred embodiments described herein, the invention being thus defined by the wording of the appended claims and the device can therefore be modified in all possible ways within the framework of the appended claims.

[0084] It should also be pointed out that all information on / related to terms such as upper, lower, upper part, lower part, etc. should be interpreted / read in the context of the device being oriented according to the drawings, which should be oriented in such a way that the reference numerals can be read in the correct manner. Therefore, these terms only indicate relative relationships in the illustrated embodiment, which may be changed if the device according to the invention has another construction / design.

[0085] It should be pointed out that even if it is not explicitly stated that features from a certain embodiment can be combined with features of another embodiment, this should be considered obvious where possible.

Claims

1. A pressure fluid processing system (37), comprising a closed pressure fluid circuit, wherein the pressure fluid circuit comprises a compressor (31) and a pressure tank (38) connected in series with each other, and a primary pressure fluid path (30) extending from the compressor (31) to the pressure tank (38) and a secondary pressure fluid path (32) extending from the pressure tank (38) to the compressor (31), the pressure fluid processing system (37) further comprising a pressure fluid accumulator (40) connected to the pressure fluid circuit via a first pressure fluid accumulator conduit (41), It is characterized in that The first pressure fluid accumulator conduit (41) includes a pump (42) configured to pump pressure fluid from the pressure fluid circuit to the pressure fluid accumulator (40) to reduce the pressure level in the pressure fluid circuit, and the pressure fluid handling system (37) includes at least one controllable component for returning pressure fluid from the pressure fluid accumulator (40) to the pressure fluid circuit to increase the pressure level in the pressure fluid circuit.

2. The pressure fluid handling system (37) according to claim 1, wherein the pressure fluid accumulator (40) is connected to the primary pressure fluid path (30) of the pressure fluid circuit via a first pressure fluid accumulator conduit (41).

3. A pressure fluid handling system (37) according to claim 1 or 2, wherein the at least one controllable component is constituted by a first controllable valve (43) configured to return the pressure fluid from the pressure fluid accumulator (40) to the pressure fluid circuit.

4. The pressure fluid handling system (37) of claim 3, wherein the first controllable valve (43) is configured to return pressure fluid from the pressure fluid accumulator (40) to the primary pressure fluid path (30) of the pressure fluid circuit.

5. The pressure fluid treatment system (37) according to claim 1 or 2, wherein the at least one controllable component is constituted by a return pump configured to pump the pressure fluid from the pressure fluid accumulator (40) to the pressure fluid circuit.

6. The pressure fluid handling system (37) of claim 5, wherein the pump (42) and the return pump consist of a single bidirectional pump.

7. A pressure fluid treatment system (37) according to claim 1 or 2, wherein the compressor (31) is a fixed displacement compressor.

8. The pressure fluid treatment system (37) according to claim 7, wherein the compressor (31) is a scroll compressor.

9. The pressure fluid treatment system (37) according to claim 1 or 2, wherein the pump (42) is constituted by an electric pump.

10. The pressure fluid handling system (37) of claim 1 or 2, wherein the primary pressure fluid path (30) comprises a condenser (50) and the secondary pressure fluid path (32) comprises an evaporator (51).

11. The pressure fluid treatment system (37) according to claim 10, wherein the pressure tank (38) is constituted by an expansion valve.

12. The pressure fluid treatment system (37) according to claim 1, wherein the pressure tank (38) is formed by a pneumatic device.

13. The pressure fluid handling system (37) of claim 12, wherein the pressure fluid circuit comprises a chamber (49) connected in series with the compressor (31) and the pneumatic device (10), wherein the chamber (49) is part of the secondary pressure fluid path (32).

14. The pressure fluid handling system (37) according to claim 12, wherein the at least one controllable component is constituted by a second controllable valve (47) configured to return the pressure fluid from the pressure fluid accumulator (40) to the secondary pressure fluid path (32).

15. A pressure fluid handling system (37) according to claim 14, wherein a check valve (48) is arranged in the secondary pressure fluid path (32), the check valve (48) is upstream of the position at which the second controllable valve (47) returns the pressure fluid to the secondary pressure fluid path (32), and the check valve (48) is arranged to allow flow in a direction toward the compressor (31).

16. A pressure fluid handling system (37) according to any one of claims 12-15, wherein the pneumatic device (10) has a demand for a variable pressure fluid flow in the pressure fluid circuit and / or a variable pressure ratio between the primary pressure fluid path (30) and the secondary pressure fluid path (32).

17. The pressure fluid handling system (37) according to any one of claims 12 to 15, wherein the pneumatic device (10) is constituted by a valve actuator configured to drive an engine valve of an internal combustion engine (1).

18. A method for controlling a pressure fluid handling system (37) according to any one of claims 1 to 17, wherein the pressure level in the pressure fluid circuit is reduced by pumping the pressure fluid from the pressure fluid circuit to the pressure fluid accumulator (40) by means of a pump (42), and wherein the pressure level in the pressure fluid circuit is increased by returning the pressure fluid from the pressure fluid accumulator (40) to the pressure fluid circuit by means of at least one controllable component.

19. The method according to claim 18, wherein the pressure level in the pressure fluid circuit is reduced by pumping pressure fluid from the primary pressure fluid path (30) to the pressure fluid accumulator (40) by means of a pump (42).

20. The method according to claim 18 or 19, wherein the pressure level in the pressure fluid circuit is increased by returning gas from the pressure fluid accumulator (40) to the primary pressure fluid path (30) of the pressure fluid circuit by means of the at least one controllable component.

21. An internal combustion engine (1) comprising a pneumatic device (10), characterized in that The internal combustion engine (1) comprises a pressure fluid handling system (37) according to any one of claims 12 to 17 for operating the pneumatic device (10).

22. The internal combustion engine (1) according to claim 21, wherein the pneumatic device (10) is constituted by a valve actuator configured to drive an engine valve configured to open / close a combustion chamber (7) included in the internal combustion engine (1).

23. An internal combustion engine (1) according to claim 21 or 22, wherein the internal combustion engine (1) comprises a cylinder head (6), wherein the pressure fluid accumulator (40) is formed by an inner cavity in a structural component of the cylinder head (6).

24. An internal combustion engine (1) according to claim 21 or 22, wherein the internal combustion engine (1) comprises a cylinder head chamber (13), wherein the cylinder head chamber (13) is part of a secondary pressure fluid path (32) of a pressure fluid circuit.

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