Separated cycle internal combustion engine

Abstract

The present disclosure relates to a split-cycle internal combustion engine device. The device includes a combustion cylinder that houses a combustion piston, and a compression cylinder that houses a compression piston. The device is configured to supply a compressed fluid to the combustion cylinder. The compression cylinder is coupled to a first liquid coolant reservoir and a second liquid coolant reservoir. A controller is configured to receive an indication of at least one parameter associated with the engine and control the delivery of at least one of a first liquid coolant from the first liquid coolant reservoir and a second liquid coolant from the second liquid coolant reservoir to the compression cylinder based on the indication of the at least one parameter such that at least one of the liquid coolants vaporizes into a gas phase during a compression stroke.

Description

[0001] Related Applications

[0002] This application is a divisional application of a Chinese application with application number 201880034898.0 and invention title "Split Cycle Internal Combustion Engine". The filing date of this application is March 13, 2018, and it claims the filing date of March 29, 2017 in the GB Patent Office as the priority date. Technical Field

[0003] The present invention relates to the field of split cycle internal combustion engines. Background Art

[0004] Conventional internal combustion engines using the Diesel cycle or the Otto cycle typically perform compression and combustion / expansion in the same cylinder. However, a split cycle internal combustion engine performs the compression and combustion / expansion phases in different cylinders. In such an engine, a fluid can be injected into the compression cylinder while the air is being compressed. This has the effect of absorbing some of the heat generated during the compression stroke, such that the compression can be considered at least quasi-isothermal.

[0005] WO 2010 / 067080 A1 discloses a split cycle reciprocating piston engine that injects liquid nitrogen into the compression cylinder to be used as a coolant. Summary of the Invention

[0006] A first aspect of the present invention provides a filter device for removing solid contaminants from a cryogenic liquid condensed into a liquid phase via a refrigeration process, wherein the cryogenic liquid is to be injected into a compression cylinder of a split cycle internal combustion engine. The filter device includes: a liquid inlet; a liquid outlet, wherein the liquid inlet is connected to the liquid outlet through a filter, and the filter includes a first part and a second part; and a diverter that guides the liquid through the first part of the filter and, in response to a control signal, guides the liquid through the second part of the filter; wherein the filter device is configured to heat a part of the first part and the second part of the filter while the liquid is diverted from the part, and the other part of the first part and the second part of the filter is used to filter the liquid coolant in the liquid coolant flow path.

[0007] A second aspect of the present invention provides a split-cycle internal combustion engine apparatus, comprising: a combustion cylinder that houses a combustion piston; a compression cylinder that houses a compression piston and supplies compressed fluid to the combustion cylinder, wherein the compression cylinder includes a liquid coolant inlet, and wherein the liquid coolant inlet is in fluid communication with a liquid coolant reservoir via a liquid coolant flow path, and a filter device for removing solid contaminants from the liquid coolant, wherein the filter includes a first part and a second part, and the first part and the second part are interchangeably used in response to a control signal from a controller such that the first part and the second part can be interchangeably moved into and out of the liquid coolant flow path; wherein the liquid coolant is a cryogenic liquid condensed into a liquid phase via a refrigeration process; and wherein the engine apparatus is configured to heat a part of the first part and the second part of the filter while liquid is diverted from the part, and the other part of the first part and the second part of the filter is used to filter the liquid coolant in the liquid coolant flow path.

[0008] A third aspect of the present invention provides a method of operating a filter device for removing solid contaminants from a cryogenic liquid condensed into a liquid phase via a refrigeration process, wherein the cryogenic liquid will be injected into a compression cylinder of a split-cycle internal combustion engine, the method comprising: guiding liquid from a liquid inlet to a liquid outlet via a first part of a filter element; in response to a control signal, guiding liquid from the liquid inlet to the liquid outlet via a second part of the filter element; and in response to guiding liquid via the second part of the filter element, heating the first part of the filter element to remove solid contaminants from the first part of the filter element while diverting the cryogenic liquid from the first part of the filter element.

[0009] A fourth aspect of the present invention provides a split-cycle internal combustion engine apparatus, comprising: a combustion cylinder that houses a combustion piston; a compression cylinder that houses a compression piston and supplies compressed fluid to the combustion cylinder, wherein: the compression cylinder includes a liquid coolant inlet for injecting a cryogenic liquid condensed into a liquid phase via a refrigeration process into the compression cylinder, wherein the liquid coolant inlet is in fluid communication with a liquid coolant reservoir via a liquid coolant flow path, the liquid coolant reservoir includes a driver that generates a pressure difference in the reservoir to drive a part of the liquid coolant into the compression cylinder; and wherein the driver includes a heater configured to heat a part of the reservoir in response to a control signal from a controller to generate a pressure difference in the reservoir to drive a part of the liquid coolant into the compression cylinder.

[0010] Aspects of the present invention can be combined with each other, and features of one aspect can be applied to other aspects. Description of the Drawings

[0011] Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, wherein:

[0012] Figure 1 A schematic diagram of an exemplary split-cycle internal combustion engine device is shown.

[0013] Figure 2 A schematic diagram of an exemplary split-cycle internal combustion engine device is shown.

[0014] Figure 3 Shows a flowchart of a method of using an engine suitable for Figure 1 and Figure 2 .

[0015] Figure 4 Shows a schematic diagram of an injection device of an engine suitable for Figure 1 and Figure 2 .

[0016] Figure 5 Shows a schematic diagram of a filter system of an engine suitable for Figure 1 and Figure 2 .

[0017] Figure 6a and Figure 6b Show an exemplary schematic diagram of a liquid coolant reservoir for use with an engine of Figure 1 and Figure 2 .

[0018] Figure 7 Shows Figure 6a and Figure 6b An alternative arrangement of the liquid coolant reservoir described and shown in Figure 1 and Figure 2 for use with an engine of

[0019] Figure 8 Is a graph showing the change in work and mass by introducing water and liquid nitrogen as exemplary liquid coolants into the compression cylinder of the split engine device (e.g., Figure 1 and Figure 2 split-cycle engine).

[0020] Figure 9 The curve of DETAILED DESCRIPTION

[0021] Figure 1Shown is a split - cycle internal combustion engine apparatus 100 configured to use two different types of liquid coolants. Two liquid coolants can be selected such that they have different thermal properties, and a combination of the two liquid coolants can be used to improve engine performance. At least one of the liquid coolants may have been condensed into its liquid phase through a refrigeration process. The engine includes a controller that, in operation, receives an indication of at least one parameter of the engine and uses the indication to control at least one of the liquid coolants to be delivered in liquid form to a compression cylinder of the split engine (e.g., by direct injection) such that the liquid coolant vaporizes into a gas phase during the compression stroke and the temperature rise caused by the compression stroke is limited by the coolant absorbing heat. Thus, the controller can be configured to deliver a combination of coolants that can be selected, for example, based on the needs of the engine. For example, at least one liquid coolant is selected such that the phase change of the liquid coolant limits the temperature rise caused by the compression stroke, such as the latent heat of vaporization as the liquid coolant vaporizes. Advantageously, this can allow for a greater mass of air per compression stroke and thus can make the engine more efficient. A more efficient engine has significant environmental benefits.

[0022] Figure 1 Shown is a split - cycle internal combustion engine apparatus 100 including a compression cylinder 10 and a combustion cylinder 20. The compression cylinder 10 houses a compression piston 12 that is connected via a connecting rod 52 to a corresponding crank on a portion of a crankshaft 70. The combustion cylinder 20 houses a combustion piston 22 that is coupled via a connecting rod 54 to a corresponding crank on a portion of the crankshaft 70. The compression cylinder 10 is connected to the combustion cylinder 20 via a heat exchanger 30. The compression cylinder 10 includes an inlet 8 for receiving air from outside the engine and an outlet 9 connected to the heat exchanger 30. The outlet 9 includes a check valve such that compressed air cannot flow back into the compression cylinder 10. The combustion cylinder 20 includes an inlet 18 and an outlet 19, the inlet 18 also being connected to the heat exchanger 30, and the outlet 19 for allowing the exhaust gas from the combustion cylinder 20 to pass through an exhaust pipe 95, and these connectors provide an air flow path for air between the compression cylinder 10 and the combustion cylinder 20 through the heat exchanger 30.

[0023] The engine 100 further includes a first liquid coolant reservoir 40, a second liquid coolant reservoir 50, a controller 60, and a fuel reservoir 80. The first liquid coolant reservoir 40 is connected to the compression cylinder 10 via a first injector 14, thereby defining a first liquid flow path, and the second liquid coolant reservoir 50 is connected to the compression cylinder 10 via a second injector 16, thereby defining a second liquid flow path. The fuel reservoir 80 is connected to the combustion cylinder 20 via a third injector 82, thereby defining a fluid flow path between the fuel reservoir 80 and the combustion cylinder 20.

[0024] Engine 100 includes a plurality of sensors, shown as black dots coupled to controller 60. However, it should be understood that the sensors shown are merely exemplary, and there may be a different number of sensors, or they may be placed in different locations. For example, the inlet 8 may also include a temperature sensor. The sensors may be coupled to controller 60 by physical wires or may be wirelessly connected. In Figure 1 the illustrated embodiment, there is a compression sensor 11 within the compression cylinder 10. The sensor may be mounted, for example, near the air inlet 8 or near one or both of the injectors 12, 14. Figure 1 The illustrated exemplary engine 100 also includes a combustion sensor 21 within the combustion cylinder 20 and a heat exchanger sensor 31 within the heat exchanger 30. Additionally, engine 100 includes a crank sensor 71 mounted on the crankshaft 70 and an exhaust sensor 91 downstream of the outlet 19 of the combustion cylinder 20. In some embodiments, the first and second liquid coolant reservoirs 40, 50 also include respective sensors, e.g., for measuring the amount of liquid, e.g., mass, contained in the reservoirs 40, 50.

[0025] Controller 60 is coupled to the sensors and at least one of the first and second injectors 14, 16. In Figure 1 the illustrated embodiment, controller 60 is coupled to the first and second injectors 14, 16, and a third injector 82.

[0026] The sensors are configured to send at least one signal to controller 60 to provide an indication of at least one parameter associated with engine 100. For example, in Figure 1 the illustrated embodiment, the compression sensor 11 is configured to measure at least one parameter associated with the compression cylinder 10. The combustion sensor 21 is configured to measure at least one parameter associated with the combustion cylinder 20. The heat exchanger sensor 31 is configured to measure at least one parameter associated with the heat exchanger 30. Additionally, the crank sensor 71 is configured to measure the RPM of the engine, and the exhaust sensor 91 is configured to measure at least one parameter of the exhaust discharged through the outlet 19 of the combustion cylinder 20.

[0027] Engine 100 is arranged such that air enters the compression cylinder 10 through the inlet 8 of the compression cylinder 10. The compression piston 12 is arranged to compress the air, and during compression, liquid coolant is added to the compression cylinder 10. The heat exchanger 30 is arranged to receive the compressed air via the outlet 9 and deliver it to the combustion cylinder 20 via the inlet 18. Engine 100 is also arranged to add fuel from the fuel reservoir 80 to the combustion cylinder 20 via the third injector 82 and combust the mixture of fuel and compressed air (e.g., by operating an ignition source not shown) to extract useful work through the rotation of the crankshaft 70.

[0028] The fuel reservoir 80 is connected to the controller 60 such that the controller 60 controls the delivery of fuel into the combustion cylinder 20. In some embodiments, the controller 60 is configured to determine the amount of fuel to be injected based on an indication of at least one parameter of the engine 200. For example, the controller 60 may be configured to obtain an indication of at least one parameter via a signal received from the exhaust sensor 91.

[0029] Each sensor is configured to send a respective signal to the controller 60, and the controller 60 is configured to determine the control of the delivery of at least one of the first liquid coolant and the second liquid coolant based on these received signals. The controller 60 controls the delivery of at least one of the first coolant and the second coolant respectively such that the liquid coolant vaporizes into a gas phase during the compression stroke of the compression piston 12, and the temperature rise caused by the compression stroke is limited by the absorption of heat by the liquid coolant. For example, the controller 60 is operable to control the timing of the first injector 14 and the second injector 16 based on the position of the compression piston 12 in the compression cylinder 10 (e.g., determined by the crank angle measured by the crank sensor 71) to distribute the liquid into the compression cylinder 10. In some embodiments, the controller 60 may additionally or alternatively be configured to operate one or more pumps in each of the respective liquid reservoirs 40, 50 to control the delivery of at least one liquid coolant to the compression cylinder 10.

[0030] The controller 60 and the injectors 14, 16 are configured to directly inject the liquid coolant into the compression cylinder 10 at a low pressure, such as less than 10 MPa, less than 5 MPa, less than 4.6 MPa, less than 1.3 MPa, less than 0.3 MPa. The advantage is that a dedicated cryogenic pump may not be required to pump the liquid coolant into the compression cylinder 10. The liquid coolant can be directly injected into the compression cylinder 10 in a liquid phase and in the form of spray droplets but with a relatively large droplet size distribution. A relatively large droplet size distribution is thermodynamically advantageous as it disperses the temperature and / or time range in which the liquid coolant vaporizes into a gas phase during the compression stroke of the compression piston 12.

[0031] The first liquid coolant may be a liquid coolant that has been condensed into a liquid phase through refrigeration. For example, the first liquid coolant may be a cryogenic liquid, such as liquid nitrogen (LN2). The second liquid coolant may be water. However, it should be understood that any other non-oxidizing, non-flammable liquefied gas may also be used as the first and / or second liquid coolant, such as a gas liquefied through a refrigeration process, such as air, oxygen, or argon. The fuel may be a fuel that requires an ignition source (e.g., the ignition source may include a spark plug in the combustion cylinder), such as gasoline, hydrogen, liquefied natural gas, and compressed natural gas. Optionally, the fuel may be a fuel that does not require an ignition source, for example, it may be a compression ignition fuel, such as diesel.

[0032] The controller 60 is configured to determine the delivery requirements of at least one liquid coolant and control the syringe to meet such delivery requirements. The delivery requirements can be based, for example, on the current operating conditions of the engine 100 (such as load or operating temperature), or can be based on the amount of liquid coolant in each of the respective reservoirs 14, 16 to conserve resources. The controller 60 is configured to determine the delivery requirements in response to receiving an indication of at least one parameter associated with the engine 100. For example, the controller 60 can include at least one look-up table (LUT) and determine the delivery requirements based on a received signal including at least one data value from a sensor and based on a comparison of the received data value in the look-up table. The received indication can be in the form of feedback (such as a signal) received from one or more of a plurality of sensors. It should be understood that in the context of the present disclosure, the controller 60 can monitor various parameters of the engine. These parameters can include parameters related to the compression cylinder 10, such as temperature, pressure, or the saturation of the liquid coolant, which can be measured at many locations throughout the engine 100.

[0033] In some embodiments, the compression sensor 11 is configured to measure the pressure and / or temperature in the compression cylinder 10, the combustion sensor 21 is configured to measure the pressure and / or temperature in the combustion cylinder 10, and the heat exchanger sensor 31 is configured to measure the oxygen concentration level, water saturation level, pressure, and temperature in the heat exchanger. Additionally, the crank sensor 71 is configured to measure the RPM of the crankshaft 70, and the exhaust sensor 91 is configured to measure the pressure and / or temperature of the exhaust, and / or the composition of the exhaust, such as the carbon dioxide concentration, nitrogen dioxide concentration, or other gas or particulate concentration in the exhaust. The controller 60 can have many other inputs, such as the current operating RPM of the compression cylinder 10 and / or the combustion cylinder 20. Similarly, the controller 60 can be configured to receive a demand signal representative of the current engine demand level, or any other indication that may affect the way liquid coolant and / or fuel is used.

[0034] In operation, the compression piston 12 is moved downward through the compression cylinder 10 by rotating the crankshaft 70 until the compression piston 12 reaches the bottom dead center (BDC), allowing air to enter the compression cylinder 10 through the inlet 8 of the compression cylinder 10. The crankshaft 70 continues to rotate and pushes the compression piston from the BDC back to the top dead center (TDC). As the compression piston 12 travels upward toward the TDC, the compression piston 12 compresses the air. The controller 60 receives an indication of at least one parameter of the engine 100 from sensors in the engine 100, and in response, the controller 60 controls the delivery of at least one liquid coolant by injecting at least one liquid coolant in a liquid phase state into the compression cylinder, for example, in the form of a liquid spray through injectors 14, 16. As the compression piston 12 continues to move toward the TDC, the injected liquid coolant vaporizes into a gas phase, and the latent heat of vaporization at least partially limits the temperature rise of the air in the compression cylinder 10 due to compression.

[0035] Then, the heat exchanger 30 receives the compressed fluid (including the vaporized liquid coolant) from the compression cylinder 10 via the outlet 9 and transfers it to the combustion cylinder 20 via the inlet 18. In this process, the heat exchanger 30 heats the compressed air to a desired temperature, for example, to assist the combustion process in the combustion cylinder 10. The controller then operates the third injector 82 to deliver fuel to the compressed air in the combustion cylinder 20, causing a mixture of fuel and compressed air and vaporized liquid coolant (e.g., by operating an ignition source such as a spark plug (not shown)) to extract useful work through the rotation of the crankshaft 70.

[0036] Several embodiments will now be discussed below, where the controller 60 receives an indication of at least one parameter of the engine 100, and in response to receiving the at least one indication, the controller 60 controls the delivery of at least one liquid coolant to the compression cylinder 10.

[0037] In a first embodiment, the first coolant is a liquid that has been liquefied through a refrigeration process, such as liquid nitrogen; the second coolant is water; and the at least one parameter is water saturation. The water saturation level is detected based on measuring the temperature and pressure of the air entering the compression cylinder 10 via the inlet 8. Using the pressure and temperature of the air in the compression cylinder 10 (which has a known volume depending on the position of the compression piston 12, and the position of the compression piston 12 can be determined by the crank angle measured by a sensor 71), the number of moles of air contained within the compression cylinder 10 can be determined. Using Dalton's law of partial pressures, the pressure of the added medium is proportional to the molar concentration. Therefore, the controller 60 can determine whether the water will boil (based on known values of the pressure-dependent boiling temperature of water, for example, stored in a lookup table in the controller 60), and by measuring the amount of water injected into the compression cylinder 10 via the injector 16 (e.g., using a flow meter), the controller 60 can determine the water saturation level.

[0038] Responsive to determining the water saturation level of the compression cylinder 10, the controller 60 can be configured to determine the amount of liquid coolant to be injected based on the water saturation level and operate the syringes 14, 16 to inject liquid nitrogen and / or water. For example, the controller 60 can use water as the sole coolant until the water saturation reaches a threshold level. Above this threshold level, only the second liquid coolant (liquid nitrogen) can be injected into the compression cylinder 10 without injecting water. Additionally or alternatively, the controller 60 can be configured to use a combination of water and liquid nitrogen to achieve a desired water saturation level. For example, the controller 60 can be configured to adjust the ratio of the two liquid coolants injected into the compression cylinder 10 based on the water saturation.

[0039] The controller 60 can include data stored, for example, in the form of a look-up table that defines the water saturation threshold. This threshold can be defined in a variety of ways. However, it is preferably to reduce the amount of liquid water in the combustion cylinder 20, for example, there is no liquid water in the combustion cylinder and only water in the form of water vapor in the combustion cylinder 20. Therefore, the water saturation threshold can be determined to be less than 100% absolute humidity.

[0040] The controller 60 can be configured to determine the threshold based on other engine parameters, such as the volume, temperature, or pressure of oxygen, as these parameters can affect the engine's function and the boiling point of water.

[0041] In a second embodiment, the controller 60 can be configured to determine the temperature in the compression cylinder 10 based on an indication received via a signal from the compression sensor 11. Responsive to the controller 60 determining that the temperature in the compression cylinder 10 is below a threshold based on the indication received from the compression sensor 11, the controller 60 reduces the delivery of both the first and second liquid coolants to the compression cylinder 10. This can occur when the engine 100 is first started and is relatively cold. Conversely, the controller 60 can be configured to increase the delivery of the first and / or second liquid coolant to the compression cylinder 10 in response to determining that the temperature is above the threshold, such as when the engine has been preheated and / or is under high load demand or operating at high RPM.

[0042] In some embodiments, the controller 60 is configured to compare a current temperature value with a threshold and make a determination based on this comparison. For example, the controller 60 is configured to determine the delivery (e.g., according to mass) of at least one of the first and second liquid coolants based on a comparison of the current temperature value with the threshold. For example, the controller 60 is configured to control the delivery of at least one of the first and second liquid coolants to be proportional to the difference from the threshold, so that the amount of liquid coolant delivered is more or less (e.g., mass) based on the greater the difference from the threshold.

[0043] The degree of change in the delivery of the first and / or second liquid coolant can be proportional to the temperature difference between the temperature inside the compression cylinder 10 (measured, for example, by the compression sensor 11) and a threshold temperature (stored, for example, in the controller 60). In response to determining that the liquid coolant delivery to the compression cylinder should be increased, the controller 60 can use only one liquid coolant (such as water) as the liquid coolant until a (water) saturation threshold is reached. A similar approach can be taken for other parameters of the engine, such as the pressure in the compression cylinder 10.

[0044] In a third embodiment, the controller 60 is configured to determine the oxygen saturation level in the heat exchanger 30 based on an indication of a parameter received via a signal from the heat exchanger sensor 31. The controller 60 is configured to cause more liquid coolant to be injected into the compression cylinder 10 when the oxygen saturation is above a threshold level. The injection of the liquid coolant can be according to the methods described above.

[0045] In a fourth embodiment, the controller 60 is configured to control the delivery in at least one liquid coolant based on the demand of the engine 100. For example, the controller 60 is configured to receive a signal from the engine 100 indicating the desired output. Of the engine (e.g., the required torque, RPM, or power output). In this embodiment, the first liquid coolant is a liquid that has been liquefied through a refrigeration process, such as liquid nitrogen; the second liquid coolant is water. The controller 60 is configured to control the delivery of the first and second liquid coolants such that in the case of higher demand (when the engine will run hotter), more of the first liquid coolant is injected into the compression cylinder 10 relative to the second liquid coolant; while in the case of lower demand (when the engine is operating at a lower temperature), the controller 60 is configured to inject more of the second liquid coolant relative to the first liquid coolant. In this way, the temperature of the compressed air in the compression cylinder 10 can be more precisely controlled to achieve more efficient combustion, thereby making the engine 100 more efficient.

[0046] In some embodiments, the injectors 14, 16, 82 can also be configured to act as sensors and send a signal to the controller 60 that provides an indication of at least one parameter associated with the engine 100. The injectors 14, 16, 82 can be configured to send a signal that indicates, for example, the temperature of the injector, the resistance of components of the injector (such as the induction coil, which can be used to cause the injector to inject liquid), and / or a measurement of the amount (such as mass) of liquid injected through the injectors 14, 16, 82. The injectors can be configured to inject the liquid coolant through direct injection and / or common rail injection, but due to the low temperatures involved, at least one of the injectors 14, 16, 82 may not include a piezoelectric drive element but can be configured to operate at low temperatures, such as less than 100 Kelvin.

[0047] In some embodiments, the controller 60 is configured to determine and control the delivery rate of one liquid coolant relative to another liquid coolant. For example, the controller 60 may include a plurality of control loops that open or close to control the proportion of coolant injected into the compression cylinder 10. These feedback loops may include measurements of exhaust temperature, engine load, desired differential temperature level, and fluid density. For example, the controller 60 may be a proportional-integral-derivative (PID) controller. In Figure 1 the illustrated embodiment, the controller 60 controls the ratio of the first liquid coolant to the second liquid coolant. Optionally, the controller 60 may be configured to focus primarily on one coolant and use the other coolant only in certain situations (e.g., when a threshold is reached). This can help conserve resources, such as when the level of one liquid coolant is low. In such an embodiment, the controller 60 may maintain the injection amount of one coolant at a selected value, and in response to determining that more liquid coolant should be added to the compression cylinder 10, the controller 60 may start adding liquid coolant only from the same liquid coolant reservoir until a threshold condition is reached. Once the threshold is reached, the controller 60 may switch to add only liquid coolant from the other container.

[0048] In some embodiments, the injection of spray droplets by the injectors 14, 16 can be controlled, for example, by the controller 60 to deliver a distribution of droplet sizes to provide stable heat absorption during the compression stroke and smooth heat transfer between the air and the liquid coolant in the compression cylinder 10. In some embodiments, this will include (e.g., by the controller 60) determining a distribution of droplet sizes that will provide heat absorption throughout the compression stroke, such as over a portion of or throughout the entire compression stroke (e.g., from BDC to TDC). In the case where the liquid coolant is a liquid that has been liquefied through a refrigeration process, the combination of the low temperature of the liquid coolant and its low pressure when injected means that the liquid coolant will be injected into the compression cylinder 10 in the liquid phase even when the engine temperature is very high.

[0049] In some embodiments, the liquid coolant is injected into the compression cylinder 10 in the form of a liquid stream. In some embodiments, the controller 60 is configured to control the delivery rate of at least one liquid coolant such that the heat absorption of the liquid coolant corresponds to the instantaneous temperature difference between the liquid coolant and the surrounding air in the compression cylinder 10.

[0050] In some embodiments, the inlet 8 may be coupled to a turbocharger or any other forced induction air intake device such that the air entering the compression cylinder 10 has already been pressurized. In some embodiments, the inlet 8 may additionally or alternatively be coupled to an intercooler to cool the pressurized air. Pressurizing and cooling the air in this manner may also mean that the measured values of the pressure and temperature of the air entering the compression cylinder 10 via the inlet 8 can be determined more precisely.

[0051] In some embodiments, the engine 100 may include a third liquid coolant reservoir and another liquid coolant injector coupled to the third liquid coolant reservoir and arranged to inject the third liquid coolant into a part of the engine 100, such as the compression cylinder 10 or the heat exchanger 30. The third liquid coolant may be different from the first and second liquid coolants and may be a non-oxidizing, non-flammable gas, such as a gas that has been liquefied into a liquid phase through a refrigeration process.

[0052] In some embodiments, the heat exchanger 30 may include an injector coupled to the liquid coolant reservoir. For example, the heat exchanger 30 may further include an injector coupled to the second liquid coolant reservoir, and the controller 60 may be configured to monitor, for example, via the heat exchanger sensor 31, the temperature of the compressed fluid transferred from the compression cylinder 10 to the combustion cylinder 20. The controller 60 may be configured to determine whether a certain amount of liquid coolant is needed to control the temperature of the gas entering the combustion cylinder 20 via the inlet 18 within a selected range. The selected range may enable efficient combustion and may be stored in the memory of the controller 60. For example, if the engine 100 is operating with difficulty (e.g., under high demands), injecting the first and second liquid coolants into the compression cylinder 10 is insufficient to maintain the temperature of the compressed air transferred from the compression cylinder 10 to the combustion cylinder 20 within the selected range, then the controller 60 may control the delivery of the liquid coolant into the heat exchanger 30 through the operation of the injector to further cool the air to the selected range.

[0053] In some embodiments, the controller 60 may be configured to deliver liquid air to the compression cylinder 10 to improve the combustion efficiency of the engine 100, or, for example, when high demands are placed on the engine 100.

[0054] Figure 2 Another embodiment of the split cycle internal combustion engine device 200 is shown. Where features Figure 1 identical or similar to those

[0055] Figure 2 are concerned, the same reference numerals are used. Figure 1 The engine 200 differs from the Figure 2In the engine 200, a second liquid coolant reservoir 50 is coupled to a heat exchanger 30. A controller 60 is configured to control the delivery of the liquid coolant from the second liquid coolant reservoir 50 such that the second liquid coolant can be injected into the heat exchanger 30 and the compression cylinder 10. The crankshaft 70 further includes a gear mechanism 75 that is configured such that the compression piston 12 and the combustion piston 22 can operate at different RPMs.

[0056] Additionally, the engine 200 is configured such that the exhaust gas from the combustion cylinder 20 passes through the outlet 19 and is directed through the heat exchanger 30 such that the exhaust gas exchanges heat with the compressed air entering the combustion cylinder 20. In this way, the temperature of the gas transferred from the compression cylinder 10 to the combustion cylinder 20 can be controlled so that the engine operates at a more efficient operating temperature.

[0057] Additionally, the heat exchanger 30 includes a condenser such that some of the second liquid coolant can be extracted from the exhaust gas and returned to the second liquid coolant reservoir 50. Then, the exhaust gas can be discharged from the heat exchanger 30 to the environment through the exhaust pipe 95. In Figure 2 the illustrated embodiment, the engine 200 further includes an emissions sensor 92 coupled to the controller 60, such as located in the exhaust gas flow path downstream of the heat exchanger 30. The emissions sensor 92 can be configured to measure the concentration of gases and / or particles exiting via the exhaust pipe 95 and send a signal to the controller 60 that includes an indication of one of these parameters.

[0058] Another difference from Figure 1 the engine 100 is that the two portions of the crankshaft 70 that are respectively attached to the two pistons 12, 22 by the connecting rods 52, 54 are not integrally connected together to rotate at the same speed. Instead, these two portions are connected by a gear mechanism 75, which can be, for example, a transmission system or a gearbox with a selectively variable transmission ratio. Additionally or alternatively, the gear mechanism 75 can include a clutch, such as a disengaging clutch.

[0059] Figure 2 The operation of the engine 200 is generally the same as that described above for Figure 1 the engine 100. However, the operation of the previously undescribed features of the engine 200 will now be described with reference to Figure 2 the following.

[0060] The condenser in the heat exchanger 30 is configured to cool the exhaust gas from the combustion chamber 20. For example, in the case where the second liquid coolant is water, the water can be cooled and condensed so that it returns to the second liquid coolant reservoir 50, which allows for a smaller second liquid coolant reservoir 50 to be provided. This may be preferred when using the engine on a vehicle without unrestricted access to water, and a water cycle can thus be used. The excess heat from the exhaust gas can also be used to provide a heating mechanism for the air in the heat exchanger, such as a heat exchanger that exchanges heat with the compressed air discharged from the compression cylinder 10 and entering the combustion cylinder 20. The controller 60 can be configured to control the operation of the heat exchanger 30 such that the compressed air transferred from the compression cylinder 10 to the combustion cylinder 20 is within a selected range. For example, the controller 60 can be configured to heat the air when it is below the selected threshold (e.g., if the engine 200 is running cold, such as when it has just been started), and it can be configured to cool the air when it is above the selected threshold (e.g., when there is a high demand on the engine 200). The controller 60 can cool the air in the heat exchanger and can control the delivery of the second liquid coolant from the second liquid coolant reservoir 50, for example, via the operation of an injector in the heat exchanger 30.

[0061] In some embodiments, the engine 200 may further include a turbocharger or other suitable device for increasing the engine efficiency by extracting energy from the exhaust gas of the combustion cylinder 20.

[0062] In some embodiments, the engine 200 may further include a supercharger or other suitable device for increasing the pressure or density of the air supplied to the engine 200. The power for the supercharger can be provided by a crankshaft, a battery, or any other suitable device.

[0063] In some embodiments, the engines 100, 200 may include a known liquid nitrogen generator of the Brayton / Joule / Thompson type. The generator may include a rotary compressor whose shaft is connected to a turbine expander and to the output of a variable ratio transmission system, the input of which is connected to the crankshaft 70. The liquid nitrogen generator also includes two heat exchangers and a fan-cooled aftercooler. In use, air is inhaled into the liquid nitrogen generator by the compressor through an inlet, and after being compressed, expanded, and passed through the heat exchangers, liquid nitrogen is produced and transferred to the reservoir 40.

[0064] Now will refer to Figure 3 Describe a method for determining the amount of coolant to be used.

[0065] In Figure 3In step 1000, the method begins. Steps 1002 and 1004 respectively include determining the demand and RPM of the engine, so that in step 1010, the controller 60 is configured to calculate the required fuel quantity to be injected from the fuel reservoir 80 into the combustion cylinder 20. In step 1012, the controller 60 uses the measured conditions of the compressed air delivered from the compression cylinder 10 to the combustion cylinder 20, that is, based on the received signals from the compression sensor 11 and the heat exchanger sensor 31, such that in step 1020 the controller 60 determines the mass of oxygen required for the required combustion effect. In step 1030, the maximum mass of the coolant is determined. In this case, the first liquid coolant is liquid nitrogen and the second liquid coolant is water.

[0066] In step 1040, the controller determines whether the oxygen level is higher than a threshold by comparing the data value based on the received sensor signal with a stored look-up table based on an indication from one of the sensors. If it is determined that the oxygen level is higher than the threshold, the method proceeds to step 1050, in which the controller 60 is configured to determine whether the water saturation threshold has been reached. However, if the oxygen level is lower than the threshold, the method proceeds to step 1045, in which the controller 60 is configured to reduce the amount of water and liquid nitrogen added to the compression cylinder.

[0067] The controller 60 can be configured to determine the required mass of oxygen based on the fuel load, for example using a look-up table that includes the known oxygen requirements for the desired combustion based on the thermodynamic properties of the engine. In some embodiments, there may be more than one oxygen source, for example, oxygen in the air and oxygen in the form of liquid oxygen / liquid air injected into the compression cylinder 10 as a liquid coolant. Accordingly, the controller 60 is configured to determine the oxygen level in the engine and it can adjust the amount of liquid coolant injected into the compression cylinder 10 to ensure that the oxygen level remains within a selected range.

[0068] The controller 60 can be configured to use one of the sensors to determine the oxygen level. A lambda meter (oxygen sensor) can be used to measure the oxygen concentration, for example the oxygen concentration in the heat exchanger 30. It is preferably ensured that the oxygen level is not too low, as this may cause soot to accumulate in the exhaust and leak in the combustion cylinder.

[0069] In step 1050, the controller determines the water saturation level, for example, based on an indication from one of the sensors. If the water saturation level has reached a selected water saturation threshold, the method proceeds to step 1060, in which the controller 60 is configured to increase the amount of liquid nitrogen to be injected into the compression cylinder 10. At this stage, if it is below the water saturation threshold, the controller 60 can avoid injecting more water into the compression cylinder 10 until the water saturation level is reached. If the water saturation level is below the water saturation threshold at step 1050, the method proceeds to step 1055, in which the controller 60 is configured to increase the amount of water injected into the compression cylinder 10. At this stage, the controller 60 can avoid injecting any liquid nitrogen into the compression cylinder 10 until the water saturation threshold is reached.

[0070] After steps 1045, 1055, and 1060, the method proceeds to step 1070. Step 1070 takes an input from step 1062, in which the heat in the exhaust gas is measured, for example, using one of the exhaust gas sensors 91 or the emission sensor 92. In step 1070, the controller 60 is configured to measure at least one of the temperature, pressure, and oxygen content in the heat exchanger 30. For example, this can be determined using the heat exchanger sensor 31. Step 1070 can start cycling through measuring the temperature, pressure, oxygen saturation, and water saturation, and the controller 60 receives signals based on these measured parameters and adjusts the delivery of the coolant accordingly.

[0071] In step 1080, the controller 60 is configured to determine whether the temperature in the compression cylinder 20 is higher than a threshold based on a temperature measurement from one of the sensors. If the temperature is high enough, for example, higher than the threshold, the method proceeds to step 1090, in which the controller 60 is configured to determine whether the pressure in the compression cylinder 20 is higher than the threshold. If the pressure is high enough, for example, higher than the threshold, the method proceeds to step 1040, as described above. For any of steps 1080, 1090, and 1040, if the threshold is not reached, the method proceeds to step 1045, in which the controller 60 is configured to reduce the amount of the two liquid coolants delivered.

[0072] Figure 4 A liquid coolant injection device 150 is shown, which is used to inject a liquid coolant into the compression cylinder 10 of a split-cycle engine (such as the engines 100 and 200 described above). The device 150 is operated by a controller (such as the controller 60 described above), which can be configured to control the delivery of at least one of a first liquid coolant and a second liquid coolant based on an indication of at least one parameter associated with the engine 100.

[0073] Figure 4 The coolant injection device 150 shown includes a liquid coolant reservoir 40 that is connected to the compression cylinder 10 of a split-cycle engine via a filter 110 and a liquid coolant injector 14. The reservoir 40 is in fluid communication with a liquid coolant fluid path that extends through the filter 110 to the liquid coolant injector 14. The liquid coolant injector 14 is directly connected to the compression cylinder 10.

[0074] The liquid coolant reservoir 40 is operable to supply liquid coolant to the filter 110 via a liquid coolant flow path. The filter 110 is operable to remove solid contaminants from the liquid coolant and direct the filtered liquid coolant to the liquid coolant injector 14, which is operable to control the injection of the liquid coolant into the compression cylinder 10.

[0075] Now described in operation is Figure 4 the system as an example. The reservoir 40 stores a liquid coolant, which can be liquefied air, water, or another liquid that has been refrigerated and condensed into a liquid phase. In this embodiment, the liquid coolant is liquid nitrogen.

[0076] As Figure 6a and Figure 6b shown, the reservoir 40 contains a driver that is capable of increasing the pressure within the reservoir 40, thereby forcing the liquid nitrogen to flow along the liquid coolant flow path. The driver can include a heater 29 and / or a pump 31, which can create a pressure differential between the reservoir 40 and the liquid coolant flow path 118. For example, the heater 29 is operable to heat a portion of the reservoir 40 in response to a control signal from the controller 60. This creates a pressure differential in the reservoir 40 to drive a portion of the liquid nitrogen into the compression cylinder 10. The heater 29 can recycle heat from the engine through the exhaust, or can include a resistor across which an electric potential difference is applied to cause heating. In some embodiments, the reservoir 40 also includes a relief valve to prevent overpressurization of the reservoir 40. In the event that the pressure in the reservoir 40 exceeds a selected threshold, the valve allows nitrogen gas generated by the heater to escape. The threshold can be based, for example, on the upper operating pressure of the liquid coolant injection system 150 (e.g., determined by the controller 60). The provision of the heater 29 in the reservoir 40 can also prevent the pressure in the reservoir 40 from dropping below atmospheric pressure, which is undesirable because it would draw ambient air into the reservoir 40, causing the air to freeze and form undesirable ice crystals.

[0077] Using the above reference Figure 6a and Figure 6bThe described method and apparatus, once a pressure difference has been achieved within the reservoir 40, causes liquid nitrogen to flow towards the compression cylinder 10 due to the generated pressure difference. The liquid coolant flow path passes through a filter 110, which removes solid contaminants from the liquid nitrogen. This filtering step helps to remove impurities in the nitrogen, such as water or carbon dioxide crystals, which could damage the liquid coolant injector 14 due to wear.

[0078] After passing through the filter 110, due to the pressure difference, the liquid nitrogen continues along the liquid coolant flow path to reach the liquid coolant injector 14. The injector 14 can be operated by a control signal from the controller 60 to inject a determined amount of liquid nitrogen into the compression cylinder 10. As described above with respect to Figures 1 - 3 the delivery of liquid nitrogen can be controlled by the controller 60 based on the received parameters.

[0079] Figure 5 An exemplary filter device 110 is shown, which is used to remove solid contaminants from the liquid coolant flow path, such as for use with the coolant injection device 150 described above with reference to Figure 4 The filter 110 includes two liquid coolant flow paths 120, 130, which are connected in parallel at their respective ends to an inlet 118 and an outlet 119. The filter 110 includes two sections 113, 115, where one section 113 is placed along the first liquid coolant flow path 120 between the inlet 118 and the outlet 119, and the second filter section 115 is placed along the second liquid coolant flow path 130 between the inlet 118 and the outlet 119. Figure 5 The illustrated embodiment also includes two diverters 111, 112, one on either side of the filter sections 113, 115, and each diverter 111, 112 is connected between the inlet 118 and the two flow paths 120, 130 and between the outlet 119 and the two flow paths 120, 130, respectively. Additionally, in the Figure 5 illustrated embodiment, there are two heating elements 114, 116, each heating element being coupled to its respective filter section 113, 115. The heating elements 114, 116 and the diverters 111, 112 are coupled to the controller 60, which can be the same controller as the controller 60 described above with respect to Figures 1 to 4 the description.

[0080] The diverters 111, 112 are operable to direct the liquid coolant along the liquid coolant flow path and are controlled by the controller 60. These diverters can be valves that change the liquid coolant flow path and allow the filter sections 113, 115 to be interchanged. The controller 60 can operate these diverters 111, 112 according to a selected routine (e.g., as stored in the controller 60), so as to allow each filter section 113, 115 to be in the liquid coolant flow path for a selected time interval before the filter sections 113, 115 are interchanged. For example, the liquid coolant flows through the first liquid flow path 120 during a first selected time interval and then through the second liquid flow path 130 during a second selected time interval, and so on.

[0081] Optionally, the controller 60 can receive a signal including sensor data, which can be used to determine the nature of the liquid coolant flow. For example, the filter device 110 can include pressure sensors arranged along the liquid coolant flow paths 120, 130, sensors at the inlet 118 and the outlet 119, and / or sensors in the reservoir 40, as well as sensors at the input of the syringe coupled to the outlet 119 of the filter device.

[0082] For example, the controller 60 can be configured to determine whether there is a blockage in the filter sections 113, 115 and operate the diverters 111, 112 and the heating elements 114, 116 accordingly. For example, if the pressure difference between the input of the filter 118 and the input of the syringe exceeds a selected threshold, this can indicate that the first filter section 113 is approaching saturation with solid contaminants and there is a significant blockage in the liquid coolant flow path 120. Therefore, the controller 60 can determine that a blocked state exists and control the diverters 111, 112 to divert the liquid from the first liquid flow path 120 and transfer it only through the second filter section 115 via the second liquid flow path 130. Since no liquid coolant flows through the first liquid flow path 120 and the first filter section 112, the first filter section 113 can be naturally heated due to the ambient temperature (and because no cold liquid coolant flows through), or it can be heated, for example, by the heating element 114 controlled by the controller 60, to remove the solid contaminants by melting and / or evaporation. Once the solid contaminants are removed, the diverters 111, 112 can be operated to return the liquid coolant through both liquid flow paths 120, 130 at once or only through one of the liquid flow paths 120, 130.

[0083] Another option can include sensing the temperature of the filter sections 113, 115. When the filter becomes "blocked" by contaminants, the local temperature of the filter sections 113, 115 may increase, indicating a blocked condition. This can be sensed by a temperature sensor such as a thermocouple and reported to the controller 60 via a sensor signal. The controller 60 can determine that the filter sections 113, 115 should be swapped based on these received sensor signals.

[0084] In some embodiments, the controller 60 can be configured to reduce the flow rate of the liquid coolant through the filter 110 to cause an increase in the temperature of the filter sections 113, 115.

[0085] In Figure 5 embodiments, the filter sections 113, 115 are copper meshes that are capable of capturing solid contaminants but allowing the liquid coolant to pass therethrough. Using a copper mesh is advantageous because it is conductive, allowing the heaters 114, 116 to be induction coils that can be located outside the liquid coolant flow path but still provide the desired heating effect. When the filter sections 113, 115 are swapped, the inactive section may be "blocked" and contain a large amount of solid contaminants. The heaters 114, 116 allow the copper mesh to be heated, causing the solid contaminants to evaporate or melt. Then it can be discharged from the filter 110 using a pressure relief valve.

[0086] In addition to using heating to remove solid contaminants, the filter can also include U-shaped elbows (e.g., in each of the liquid coolant flow paths 120, 130) to prevent any unevaporated liquid (e.g., water) from flowing upward and being carried away with the liquid coolant flow, potentially damaging the engines 100, 200. The U-shaped elbows can also include valves that are arranged such that the U-shaped elbows can be emptied at selected intervals, e.g., by the operation of the controller 60 or by the user.

[0087] Alternative embodiments can use heating devices different from those described above. These can include using recycled heat from the exhaust of the split-cycle engines 100, 200 to heat the filter sections 113, 115. The advantage of this is that no additional heating system is required and it is more efficient due to its use of recycled heat. Depending on the heating of the surrounding devices, the filter sections 113, 115 may not require active heating. Instead, they can simply be allowed to heat up to ambient temperature, which is sufficient to enable the solid contaminants to be removed from the filter 110.

[0088] In addition to different heating devices, the material of the filter sections 113, 115 can also be changed. For example, instead of copper in the above embodiments, the filter sections 113, 115 can include an aluminum mesh that can also be heated by induction heating. Other materials can also be used, such as carbon fiber.

[0089] Figure 7 shows Figure 6a and Figure 6b the optional arrangements of liquid coolant reservoirs that can be used with the split-cycle engine device described and shown in Figure 1 and Figure 2 The reservoirs 40, 50 include a heat-insulated tank 701 which is arranged to enclose a liquid coolant 703, such as a refrigerant, such as liquid nitrogen, which has been condensed into a liquid phase by a refrigeration process. At the bottom of the heat-insulated tank 701 there is a driver 29 which is arranged to create a pressure difference in the heat-insulated tank 701, such as the driver described above with respect to Figure 6a and Figure 6b In the shown embodiment, the driver 29 is a resistive element which is arranged to provide a certain degree of resistive heating to the liquid coolant when an electric current passes through the liquid coolant. The heat-insulated tank 701 is connected via a heat-insulated pipeline 718 passing through a filter 110 and a syringe 14 to a compression cylinder 10 of a split-cycle engine 100 (such as the engine of Figure 1 and Figure 2 ), as described with respect to the previous figures.

[0090] The heat-insulated pipeline 718 extends through the wall of the heat-insulated tank 701 and extends downward to the bottom of the tank 701 so that even when the liquid level of the liquid coolant in the tank is low, the heat-insulated pipeline 718 can still extract the liquid coolant. It should be understood that the heat-insulated pipeline 718 does not need to be heat-insulated inside the heat-insulated tank 701. The heat-insulated pipeline 718 is connected to the tank via a valve 705 and a gas return valve 707 to fill the heat-insulated tank 701. The heat-insulated tank 701 also includes two pressure relief valves 709 so that the pressure in the heat-insulated tank 701 does not reach a dangerous level. In the shown embodiment, the filter device 110 also includes two pressure relief valves 711. For example, one of the pressure relief valves 709, 711 can be set to the normal operating pressure of the device, while the other can be set to a pressure higher than the normal operating pressure but lower than the maximum safe operating pressure.

[0091] In some embodiments, as Figure 7 shown, the heat-insulated pipeline 718 can be connected to a separate feed pipeline 722, such as at the proximal end of the valve 705, but in other embodiments, it should be understood that the heat-insulated pipeline 718 can be used as a feed pipeline. In the Figure 7 shown embodiment, an optional spray bar 720 is also connected to the heat-insulated pipeline 718 / feed pipeline 722 inside the tank. The spray bar 720 can be used to supply a liquid coolant (for example, the recycled liquid coolant recovered from the heat exchanger 30 described above) to cool the liquid coolant 703 stored in the tank 701 in the form of a spray.

[0092] Figure 7 The arrangement of the tank 701 shown in FIG. results in no trapped volume of liquid coolant and ensures that the pressure in the reservoir 40 never drops below atmospheric pressure. In some embodiments, for example, two valves arranged in parallel on the pipeline 718 are such that if icing occurs, there will be no residual liquid coolant and the pressure in the reservoir 40 will not increase. The tank 701 is also arranged to reduce the number of heat leakage paths occurring and to draw liquid coolant from near the bottom of the tank 701.

[0093] Figure 8 A graph showing the variation of work and mass is presented when water and liquid nitrogen (e.g., liquid coolant) are introduced into the compression cylinder of a split-cycle engine device (e.g., the split-cycle engine device described above). At point A, no LN2 or water is added. The starting point at the Y-axis intersection is two families. Above A, it is the percentage of the mass compressed by the compressor per stroke with the increase of liquid nitrogen (LN2), where each line represents the increase of water. In each case, the amount of air entrained into the compression cylinder is constant.

[0094] Below A, the graph illustrates that the mass increase of water and LN2 is the same, but shows the variation of specific work. At the marked point, the mass compressed per stroke reaches 150%, but the specific work required to achieve this without adding liquid nitrogen or water is only about 65 - 70%. This is important for a six-cylinder engine because the compression cylinder can be completely removed from the engine, thereby reducing friction and pumping losses while still generating the same specific work as a conventional six-cylinder engine.

[0095] It is noteworthy that at this time, the O2 molecule concentration drops to 65% of normal air (under standard conditions). Depending on the load point, it may be desirable to use liquid air or add liquid oxygen instead of LN2 to facilitate a greater fuel load. Usually, there is an excess of oxygen, but when the engine demand is high, it may be necessary to add more oxygen.

[0096] In some embodiments, the air inhaled into the compression cylinder 10 can be intercooled first. This increases the density of the air, but due to the colder air in the compression cylinder 10 (which may be ineffective for combustion), it results in heat loss. The engine can be configured such that before the air enters the compression cylinder 10, the incoming air exchanges heat with one of the liquid coolants (e.g., water), so that the air is cooled and the water is heated before being injected into the compression cylinder 10.

[0097] Figure 9 The effect of changing the inlet temperature of the air that is inhaled into the compression cylinder and water is injected into the compression cylinder as a liquid coolant is shown. At Figure 9In this case, before being drawn into the compression cylinder 10, the incoming air is used to heat water for cooling. By providing cooler air, the air density increases, thereby allowing a greater mass of air to be supplied into the compression cylinder 10. A greater mass of air contains more oxygen, which may be desirable for combustion. Figure 9 Shows that when using cooler / condenser air, the mass percentage of the working fluid per stroke is higher.

[0098] The effect of supplying more air and / or preheating the water to the compression cylinder 10 is to increase the boiling temperature of the water in the compression cylinder 10. This allows the water to absorb more heat before vaporizing.

[0099] Generally referring to the accompanying drawings, it should be understood that the schematic functional block diagrams are used to indicate the functions of the systems and devices described herein. However, it should be recognized that the functions need not be divided in this manner and should not be construed as implying any particular hardware structure other than the hardware described and claimed below. The functions of one or more of the elements shown in the drawings may be further subdivided and / or distributed throughout the devices of the present disclosure. In some embodiments, the functions of one or more of the elements shown in the drawings may be integrated into a single functional unit.

[0100] In the context of the present disclosure, it should be understood that although reference has been made to two or three liquid coolants being used, this is not restrictive as more liquid coolants may be used. Additionally, the liquid coolants may be pre-mixed before being injected together into the compression cylinder 10, or they may be injected separately. The controller 60 may determine the coolant mixture based on the needs of the engine and thermodynamic variables. For example, the controller 60 may determine that more oxygen should be added to the compression cylinder 10, and accordingly, the controller may pre-mix an oxygen-containing coolant with another coolant in a selected ratio to meet the oxygen demand.

[0101] There may be a connection between the liquid coolant reservoirs that can be controlled by the controller 60 to enable pre-mixing of the coolants. Optionally, the syringe may have two fluid inlets, and the controller 60 may control the flow rate of each fluid into the syringe to meet the selected ratio of coolants in the mixture. Thus, the coolants may be pre-mixed in a selected ratio before injection, which can be determined and controlled by the controller 60.

[0102] In some implementations, one or more storage elements may store data and / or program instructions for implementing the operations described herein. Embodiments of the present disclosure provide a tangible, non-transitory storage medium including program instructions that are operable to program a processor to perform any one or more of the methods described and / or claimed herein and / or to provide a data processing device described and / or claimed herein.

[0103] The activities and devices outlined in this document can be implemented using fixed logic such as components like logic gates or programmable logic such as software and / or computer program instructions executed by a processor. Other kinds of programmable logic include programmable processors, programmable digital logic (e.g., field programmable gate arrays (FPGAs), erasable programmable read-only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs)), application specific integrated circuits, ASICs, or any other kind of digital logic, software, code, electronic instructions, flash memory, optical disks, CD-ROMs, DVD ROMs, magnetic or optical cards, other types of machine-readable media suitable for storing electronic instructions, or any suitable combination thereof.

[0104] It should be understood from the foregoing discussion that the embodiments shown in the drawings are merely exemplary and include features that can be generalized, removed, or replaced as described herein and in the claims. Other embodiments and variations of the devices and methods described herein will be apparent to those skilled in the art within the context of the present disclosure.

Claims

1. A filter device for removing solid contaminants from a cryogenic liquid condensed into a liquid phase via a refrigeration process, wherein the cryogenic liquid is to be injected into a compression cylinder of a split-cycle internal combustion engine, the filter device comprising: A liquid inlet; A liquid outlet, wherein the liquid inlet is connected to the liquid outlet via a filter, the filter comprising a first part and a second part; And A diverter that directs liquid through the first part of the filter and, in response to a control signal, directs liquid through the second part of the filter; Wherein the filter device is configured to heat a part of the first and second parts of the filter while liquid is diverted from that part, and the other of the first and second parts of the filter is for filtering the liquid coolant in the liquid coolant flow path.

2. The filter device according to claim 1, wherein Each part of the filter is located in a corresponding liquid coolant flow path connected between the inlet and the outlet.

3. A split-cycle internal combustion engine device, comprising: A combustion cylinder that houses a combustion piston; A compression cylinder that houses a compression piston and supplies compressed fluid to the combustion cylinder, wherein the compression cylinder includes a liquid coolant inlet, and wherein the liquid coolant inlet is in fluid communication with a liquid coolant reservoir via a liquid coolant flow path, and A filter device for removing solid contaminants from the liquid coolant, wherein the filter comprises a first part and a second part, and the first part and the second part are interchangeably used in response to a control signal from a controller such that the first part and the second part can be interchangeably moved into and out of the liquid coolant flow path; Wherein the liquid coolant is a cryogenic liquid condensed into a liquid phase via a refrigeration process; and Wherein the split-cycle internal combustion engine device is configured to heat a part of the first and second parts of the filter while liquid is diverted from that part, and the other of the first and second parts of the filter is for filtering the liquid coolant in the liquid coolant flow path.

4. The split-cycle internal combustion engine device according to claim 3, wherein the split-cycle internal combustion engine device further comprises a heater that heats the corresponding part of the filter.

5. The split-cycle internal combustion engine device according to claim 3, wherein the split-cycle internal combustion engine device further comprises a heater that heats the corresponding part of the filter, and the heater uses the residual heat from the exhaust of the split-cycle internal combustion engine.

6. The split-cycle internal combustion engine device according to claim 3, wherein the split-cycle internal combustion engine device further comprises a heater that heats the corresponding part of the filter, and the heater operates by an induction heating process.

7. An operating method of a filter device for removing solid contaminants from a cryogenic liquid condensed into a liquid phase via a refrigeration process, wherein the cryogenic liquid is to be injected into a compression cylinder of a split-cycle internal combustion engine, the method comprising: Directing liquid from the liquid inlet to the liquid outlet via a first part of a filter element; In response to a control signal, direct liquid from the liquid inlet to the liquid outlet via a second portion of the filter element; and In response to directing liquid via the second portion of the filter element, heat a first portion of the filter element to remove solid contaminants from the first portion of the filter element while diverting the cryogenic liquid from the first portion of the filter element.

8. The method according to claim 7, further comprising: In response to directing liquid via the first portion of the filter element, heat a second portion of the filter element to remove solid contaminants from the second portion of the filter element.

9. A split-cycle internal combustion engine device, comprising: A combustion cylinder that houses a combustion piston; A compression cylinder that houses a compression piston and supplies compressed fluid to the combustion cylinder, wherein: The compression cylinder includes a liquid coolant inlet for injecting cryogenic liquid condensed into a liquid phase via a refrigeration process into the compression cylinder, wherein the liquid coolant inlet is in fluid communication with a liquid coolant reservoir via a liquid coolant flow path, the liquid coolant reservoir includes a driver that generates a pressure difference in the reservoir to drive a portion of the liquid coolant into the compression cylinder; and Wherein the driver includes a heater configured to heat a portion of the reservoir in response to a control signal from a controller to generate a pressure difference in the reservoir to drive a portion of the liquid coolant into the compression cylinder.

10. The device according to claim 9, wherein, The driver includes a pump configured to generate a pressure difference in the reservoir in response to a control signal from a controller to drive a portion of the liquid coolant into the compression cylinder and drive fuel from the reservoir into the compression cylinder.

Images