Control device and control method for air inlet temperature of ammonia engine

Abstract

The invention provides a control device and method for the air inlet temperature of an ammonia engine, and belongs to the technical field of engine control, the device comprises an intercooler, the output end of the intercooler is communicated with the input end of a liquid ammonia cylinder, and a first valve is arranged on a branch where the intercooler is located; a second valve is arranged on the intercooling bypass branch; the input end of the EGR cooler communicates with the output end of the liquid ammonia cylinder through a fifth valve, the output end of the EGR cooler communicates with the input end of the liquid ammonia cylinder, and a branch where the EGR cooler is located is provided with a third valve; a fourth valve is arranged on the EGR bypass branch; and the controller is used for controlling the first valve, the third valve and the fifth valve to be closed and controlling the second valve to be opened under the working conditions of cold start and low load, and adjusting the opening degree of the fourth valve based on an air inlet temperature target value. The technical problem that when an existing ammonia engine uses liquid ammonia fuel for gas inlet channel injection or direct injection in a cylinder in a low-temperature environment, the temperature is low due to latent heat of vaporization of liquid ammonia can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of engine control, and in particular to a control device and a control method for the intake temperature of an ammonia engine. Background Art

[0002] In the context of "carbon neutrality", ammonia, as a 100% renewable zero-carbon fuel, can power ships, trucks and engineering vehicles, and has great potential in the transition from fossil fuels to zero-carbon fuels. Ammonia is a gas that is easily liquefied. When cooled to -33.4°C at normal pressure or pressurized to 7-8 atmospheres at room temperature, ammonia will liquefy into a colorless liquid. The properties of ammonia that are easy to liquefy and zero carbon make it very suitable as a fuel for internal combustion engines. The latent heat of vaporization of liquid ammonia is as high as 1371 KJ / kg, and the latent heat of vaporization of diesel is 375 KJ / kg. Therefore, when using liquid ammonia as fuel, its higher latent heat of vaporization will cause the intake duct and cylinder temperature to be too low, the liquid ammonia will not be fully vaporized, and the wet wall problem will occur. At the same time, it will also cause uneven mixing of the mixture, poor combustion effect, and reduced combustion efficiency. In addition, problems such as difficulty in cold starting and poor responsiveness in acceleration conditions will also occur.

[0003] For the engine structure with EGR (Exhaust Gas Re-circulation) system, the main function of the EGR system cooler is to reduce the temperature of the exhaust gas flowing back from the exhaust system to the intake system. This is because during the operation of the engine, part of the burned exhaust gas will be reintroduced into the intake system, mixed with fresh air and then re-entered into the cylinder for combustion. However, these exhaust gases usually have a high temperature. If they are not cooled, they may cause excessive heat load on the engine's intake system, cylinder wall, piston and other components, affecting the performance and life of the engine.

[0004] When the engine uses turbocharging or supercharging technology, the supercharger (compressor) will significantly increase the intake pressure, but it will also increase the intake temperature. High-temperature air will reduce the density of the air, which will affect the engine's charging efficiency. The intercooler cools the pressurized air and reduces its temperature, thereby increasing the intake density and allowing the engine to inhale more and denser air.

[0005] However, during engine operation, due to the complexity of the operating conditions, it is sometimes necessary to adjust the cooling effect of the intake system to adapt to different needs. For example, when the engine is running in a low-load state in a cold environment, especially during cold start and the initial stage after cold start, due to the low EGR rate and relatively low exhaust temperature under natural conditions, if the same cooling strategy as the high-load condition is adopted at this time, that is, all exhaust gas in the EGR branch is allowed to flow through the EGR cooler for cooling, it may cause the exhaust gas to have an abnormally low temperature when it flows out of the EGR module. Similarly, due to the low external ambient temperature, if the pressurized air is still cooled through the intercooler at this time, it may cause the intake temperature to be too low, thereby affecting the cold start performance of the engine and having an adverse effect on engine performance.

[0006] In addition, under low temperature and low load conditions, the thermal efficiency of the engine may be affected. Appropriate intake temperature can enable the engine to reach normal operating temperature faster, thereby improving thermal efficiency, and also helping to improve the atomization effect of the fuel, promote the full combustion of the fuel, and further improve the performance of the engine.

[0007] Inappropriate EGR cooling and intercooling strategies in low-temperature environments may cause a series of problems, including intake air icing, increased risk of blockage, and accelerated material aging, which may ultimately have an adverse effect on the vehicle's dynamics.

[0008] In summary, when existing ammonia engines use liquid ammonia fuel for intake port injection or direct injection in a low-temperature environment, there is a problem of low temperature caused by the latent heat of vaporization of liquid ammonia, which in turn causes problems such as intake icing, increased risk of blockage, and accelerated material aging in the ammonia engine. Summary of the invention

[0009] In view of this, it is necessary to provide a control device and method for the intake temperature of an ammonia engine to solve the technical problem that when the existing ammonia engine uses liquid ammonia fuel for intake port injection or direct injection in a low temperature environment, the latent heat of liquid ammonia vaporization causes the temperature to be low.

[0010] In order to solve the above problems, on the one hand, the present invention provides a control device for the intake temperature of an ammonia engine, comprising: An intercooler, the input end of which is connected to the compressor, the output end of which is connected to the input end of the liquid ammonia cylinder, and a first valve is provided in the branch where the intercooler is located; An intercooler bypass branch, the input end of which is connected to the compressor, and the output end of which is connected to the input end of the liquid ammonia cylinder, and a second valve is provided on the intercooler bypass branch; The EGR cooler has an input end connected to the output end of the liquid ammonia cylinder through a fifth valve, and an output end connected to the input end of the liquid ammonia cylinder, and a third valve is provided on the branch where the EGR cooler is located; The EGR bypass branch has an input end connected to the output end of the liquid ammonia cylinder, an output end connected to the input end of the liquid ammonia cylinder, and a fourth valve is provided on the EGR bypass branch; The controller is used to control the first valve, the third valve and the fifth valve to close, and the second valve to open under cold start and low load conditions, and to adjust the opening of the fourth valve based on the intake air temperature target value.

[0011] In a possible implementation, the first valve and the second valve are two independent valves, or constitute a three-way butterfly valve.

[0012] In a possible implementation, the third valve and the fourth valve are two independent valves, or constitute a three-way butterfly valve.

[0013] In a possible implementation, the controller is further configured to determine the required mass of liquid ammonia fuel based on the operating conditions of the ammonia engine.

[0014] In one possible implementation, the controller is used to determine the energy required for vaporizing the liquid ammonia based on the required liquid ammonia fuel mass, and determine the target intake temperature of the ammonia engine based on the target intake amount of the ammonia engine, the temperature of the target intake amount reduced by the vaporization of the liquid ammonia, and the energy required for vaporizing the liquid ammonia.

[0015] In a possible implementation, the controller is configured to adjust the opening of the fourth valve by adopting a PID control strategy based on a target intake temperature of the ammonia engine and a real-time opening of the fourth valve.

[0016] In a possible implementation, the controller is also used to control the third valve and the fifth valve to open and the fourth valve to close under medium and high load conditions, and determine the opening of the first valve and the second valve based on the intake temperature target value of the ammonia engine.

[0017] In a possible implementation, the controller is further configured to adjust the openings of the first valve and the second valve using a PID control strategy based on the intake air temperature target value of the ammonia engine and the real-time openings of the first valve and the second valve.

[0018] On the other hand, the present invention further provides a method for controlling the intake temperature of an ammonia engine, the control method being applied to any of the control devices described above, the control method comprising: The controller controls the first valve, the third valve and the fifth valve to be closed, and controls the second valve to be opened under cold start and low load conditions; The controller adjusts the opening degree of the fourth valve based on the intake air temperature target value.

[0019] In a possible implementation, the method for controlling the intake temperature of an ammonia engine further includes: The controller controls the third valve and the fifth valve to open and the fourth valve to close under medium and high load conditions, and determines the openings of the first valve and the second valve based on a target intake air temperature of the ammonia engine.

[0020] The beneficial effect of adopting the above implementation mode is as follows: the control device and control method of the intake air temperature of the ammonia engine provided by the present invention are provided with a first valve at the output end of the intercooler, a second valve on the intercooler bypass branch, a fifth valve on the input end of the EGR cooler, a third valve on the output end of the EGR cooler, and a fourth valve on the EGR bypass branch, and the controller determines the intake air temperature target value of the ammonia engine based on the required liquid ammonia fuel quality, and controls the first valve, the third valve and the fifth valve to be closed under cold start and low load conditions, and controls the second valve Open, and adjust the opening of the fourth valve based on the intake air temperature target value, so as to adjust the cooling strategies of the EGR system and the intercooler system at the same time under low load conditions in cold environment, reduce the amount of exhaust gas flowing through the EGR cooler or reduce the cooling efficiency of the cooler to ensure that the exhaust gas maintains an appropriate temperature when flowing out of the EGR module, and through the intercooler bypass, the pressurized air can bypass the intercooler and directly enter the engine, thereby solving the technical problem that when the existing ammonia engine uses liquid ammonia fuel for intake port injection or direct injection in the cylinder under low temperature environment, the latent heat of liquid ammonia vaporization causes the temperature to be low. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 A schematic structural diagram of a first embodiment of a control device for intake air temperature of an ammonia engine provided by the present invention; Figure 2 A schematic structural diagram of a second embodiment of the control device for intake air temperature of an ammonia engine provided by the present invention; Figure 3 A schematic structural diagram of a third embodiment of the control device for intake air temperature of an ammonia engine provided by the present invention; Figure 4 A schematic structural diagram of a fourth embodiment of the control device for intake air temperature of an ammonia engine provided by the present invention; Figure 5 A schematic structural diagram of a fifth embodiment of the control device for intake air temperature of an ammonia engine provided by the present invention; Figure 6A schematic structural diagram of a sixth embodiment of the control device for intake air temperature of an ammonia engine provided by the present invention; Figure 7 A flow chart of an embodiment of a method for controlling intake air temperature of an ammonia engine provided by the present invention; Figure 8 The present invention is a flow chart of another embodiment of the method for controlling the intake air temperature of an ammonia engine provided by the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0024] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more than two.

[0025] The terms "including" and "having" and any variations thereof in the embodiments of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product or equipment comprising a series of steps or modules is not necessarily limited to those steps or modules clearly listed, but may include other steps or modules not clearly listed or inherent to these processes, methods, products or equipment.

[0026] The naming or numbering of the steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0027] Reference to an "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0028] The present invention provides a control device and a control method for the intake temperature of an ammonia engine, which are respectively described below.

[0029] like Figure 1 As shown, the present invention provides a control device for intake air temperature of an ammonia engine, comprising: An intercooler, the input end of which is connected to the compressor, the output end of which is connected to the input end of the liquid ammonia cylinder, and a first valve is provided in the branch where the intercooler is located; An intercooler bypass branch, the input end of which is connected to the compressor, and the output end of which is connected to the input end of the liquid ammonia cylinder, and a second valve is provided on the intercooler bypass branch; An EGR (Exhaust Gas Re-circulation) cooler, the input end of which is connected to the output end of the liquid ammonia cylinder through a fifth valve, the output end of which is connected to the input end of the liquid ammonia cylinder, and a third valve is provided on the branch where the EGR cooler is located; The EGR bypass branch has an input end connected to the output end of the liquid ammonia cylinder, an output end connected to the input end of the liquid ammonia cylinder, and a fourth valve is provided on the EGR bypass branch; The controller is used to control the first valve, the third valve and the fifth valve to close and the second valve to open under cold start and low load conditions, and to adjust the opening of the fourth valve based on the intake air temperature target value to adjust the actual intake air temperature value to the intake air temperature target value.

[0030] It is understandable that the controller can be an engine control unit (ECU) or a vehicle control unit (VCU). The first valve is the intercooler rear valve S1, the second valve is the intercooler bypass valve S2, the third valve is the EGR cooler rear valve S3, the fourth valve is the EGR bypass valve S4, and the fifth valve is the EGR valve.

[0031] Figure 1 The structure diagram of the control device of the intake temperature of the ammonia engine corresponding to the direct injection of liquid ammonia into the cylinder is shown. In another embodiment, the present invention also provides Figure 2 The structure diagram of the control device of the intake temperature of the ammonia engine corresponding to the liquid ammonia intake port injection is shown.

[0032] The control device for the intake air temperature of an ammonia engine provided by the present invention aims to optimize the intake air temperature and intake air efficiency under low-temperature cold start conditions and low-load conditions of the engine. The control device for the intake air temperature of an ammonia engine provided by the present invention allows a part of the exhaust gas to be cooled through the EGR cooler before passing through the EGR valve (fifth valve), while the other part bypasses the EGR cooler through a bypass branch, and is mixed through a two-way / three-way butterfly valve upstream / downstream of the EGR cooler, so as to accurately control the temperature and flow of the exhaust gas entering the intake manifold. Similarly, this scheme allows a part of the supercharged gas to be cooled through the intercooler before passing through the throttle, while the other part bypasses the intercooler through a bypass branch, and is mixed through a three-way butterfly valve downstream of the intercooler, so as to accurately control the temperature and flow of the supercharged gas entering the intake manifold. Through the combined action of the above two, the precise control of the overall intake air temperature and flow of the engine is achieved together.

[0033] The control device for the intake air temperature of an ammonia engine provided by the present invention comprises: 1) EGR cooler: responsible for cooling part of the exhaust gas discharged from the engine, lowering its temperature to reduce the generation of nitrogen oxides (NOx).

[0034] 2) EGR bypass branch: provides a channel for uncooled exhaust gas to bypass the EGR cooler.

[0035] 3) Intercooler: responsible for cooling the high-temperature and high-pressure gas from the supercharger, reducing its density and increasing the engine's air intake.

[0036] 4) Intercooler bypass branch: provides a channel for the uncooled boost gas to bypass the intercooler.

[0037] 5) Three-way butterfly valve composed of the first valve and the second valve, and the three-way butterfly valve composed of the third valve and the fourth valve: installed downstream / upstream of the EGR cooler and the intercooler, divided into two air chambers on the left and right, one side is used to adjust the mixing ratio of the cooled exhaust gas and the uncooled exhaust gas, and the other side is used to adjust the mixing ratio of the cooled boost gas and the uncooled boost gas. The degree of opening of the butterfly valve determines the mixing ratio of the hot and cold gases. The characteristics of the two-way butterfly valve include: the valve body is made of corrosion-resistant and high-temperature resistant materials to withstand the high temperature and high pressure environment of the exhaust gas and the boost gas. The butterfly plate is used as a control element to change the opening of the channel by rotation, thereby adjusting the flow of the exhaust gas. The edge of the butterfly plate is usually specially treated to reduce fluid resistance and improve sealing performance. A sealing ring or sealing gasket is arranged between the butterfly plate and the valve seat to ensure that the exhaust gas leakage can be effectively prevented in the closed state. The actuator of the butterfly valve (such as electric, pneumatic or hydraulic drive) receives a signal from the engine control unit (ECU) to accurately control the rotation angle of the butterfly plate to achieve accurate regulation of the exhaust gas flow.

[0038] 6) EGR valve: Located after the three-way butterfly valve, it controls the amount of mixed exhaust gas entering the intake manifold.

[0039] 7) Throttle: Located after the three-way butterfly valve, it controls the amount of mixed pressurized gas entering the intake manifold.

[0040] The three-way butterfly valve used in the present invention includes a valve body, a transmission shaft, three valve plates (valve plate 1, valve plate 2, valve plate 3), a motor, and a cooling water jacket arranged in the valve body. Three independent air flow channels are arranged inside the valve body, each channel corresponds to a valve plate, and the valve plate is connected to the motor through a transmission shaft to achieve synchronous control. The phase angles of valve plates 2 and 3 are the same, and they are arranged at a 90° phase angle difference from valve plate 1, ensuring that in the default state, the valve plate of channel 1 is fully open, while the valve plates of channels 2 and 3 are fully closed.

[0041] The key technologies and innovations of the present invention include: Single drive shaft control: One drive shaft is used to control the opening and closing of three valve plates at the same time, and it is driven by a single motor, which simplifies the structure, reduces costs and improves reliability.

[0042] Cooling channel design: A cooling water jacket is provided inside the valve body. By circulating cooling water, the high-temperature gas flowing through the valve body can be cooled or the low-temperature gas can be kept warm, thus expanding the application range of the valve.

[0043] Flexible opening adjustment: Through precise control of the motor, all valves can be adjusted to any opening from fully closed to fully open, including half-open state, to meet the gas flow requirements under different working conditions.

[0044] Variable channel diameter: According to actual usage, channels with different diameters can be selected to optimize gas flow resistance and improve throttling efficiency.

[0045] In some embodiments, the first valve and the second valve are two independent valves, or constitute a three-way butterfly valve.

[0046] The third valve and the fourth valve are two valves independent of each other, or constitute a three-way butterfly valve.

[0047] It is understandable that if Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the first valve S1 and the second valve S2 of the present invention can constitute a three-way butterfly valve S12, and the third valve S3 and the fourth valve S4 can also constitute a three-way butterfly valve S34.

[0048] If the design of the three-way butterfly valve is highly integrated and more compact, it can be more easily integrated with other system components (such as EGR cooler, EGR valve, intercooler, etc.), which can significantly reduce the length and complexity of the bypass line. This not only helps to save valuable engine compartment space, but also reduces the difficulty and cost of piping layout. This high level of integration not only reduces system complexity, but also improves the reliability and maintainability of the overall system. By closely combining the three-way butterfly valve with the EGR cooler and intercooler circuits, a fully functional and compact overall module can be formed. This modular design simplifies the installation process and improves the overall performance and reliability of the system. At the same time, it also facilitates subsequent maintenance and replacement work because the entire module can be disassembled and assembled as a whole.

[0049] Although two traditional solenoid valves can also play a role in the EGR bypass system, their size and shape may limit the close integration with other components, thus affecting the overall layout and efficiency of the system. Traditional solenoid valves may require additional pipes and connectors to connect the EGR cooler and the EGR valve, which increases the complexity and space occupied by the system. Because the connection between the traditional solenoid valve and the EGR cooler is usually loose, it is difficult to achieve a high degree of modularity. This may result in more time and manpower investment during installation, maintenance and replacement.

[0050] In addition, the three-way butterfly valve has better flow regulation performance and can more accurately control the mixing ratio of hot and cold gases in different air chambers and the amount of exhaust gas recirculation. Simple structure, high reliability, and reduced cost: The design of one drive shaft controlling three valve plates greatly simplifies the structure, improves the reliability and stability of the system, and reduces manufacturing costs compared to the traditional method of independent control of multiple valve plates. Wide range of applications: The integrated cooling function enables the throttle valve to handle both high-temperature and low-temperature gases, broadening the scope of application. Small gas flow resistance: By adjusting the channel diameter and the valve plate opening, the gas flow resistance can be accurately controlled to improve the throttling efficiency.

[0051] This is essential for optimizing engine performance and reducing emissions. The exhaust gas in the EGR system is hot and may contain corrosive substances. The three-way butterfly valve is usually made of high temperature and corrosion resistant materials to ensure long-term stable operation.

[0052] In some embodiments, the controller is further configured to determine a required mass of liquid ammonia fuel based on operating conditions of the ammonia engine.

[0053] In some embodiments, the controller is used to determine the energy required for vaporizing the liquid ammonia based on the required liquid ammonia fuel mass, and determine the target intake temperature of the ammonia engine based on the target intake amount of the ammonia engine, the temperature of the target intake amount reduced by the vaporization of the liquid ammonia, and the energy required for vaporizing the liquid ammonia.

[0054] In some embodiments, the controller is configured to adjust the opening of the fourth valve using a PID control strategy based on a target intake air temperature of the ammonia engine and a real-time opening of the fourth valve.

[0055] In some embodiments, the controller is further configured to control the third valve and the fifth valve to open and the fourth valve to close under medium and high load conditions, and determine the openings of the first valve and the second valve based on the intake air temperature target value of the ammonia engine.

[0056] In some embodiments, the controller is further configured to adjust the openings of the first valve and the second valve using a PID (proportional, integral, differential) control strategy based on the intake temperature target value of the ammonia engine and the real-time openings of the first valve and the second valve.

[0057] In one embodiment, the working process of the control device for the intake temperature of an ammonia engine provided by the present invention includes: 1) Exhaust gas diversion: The exhaust gas discharged from the engine is divided into two paths at a specific location, one path enters the EGR cooler, and the other path passes through the bypass branch.

[0058] 2) Compressed gas diversion: The air after being pressurized by the supercharger is divided into two paths at a specific position, one path enters the intercooler, and the other path passes through the bypass branch.

[0059] 3) Exhaust gas cooling: The exhaust gas entering the EGR cooler exchanges heat with the coolant through the cooling pipe, and the temperature is significantly reduced.

[0060] 4) Boost gas cooling: The boost gas entering the intercooler exchanges heat with the external environment through the cooling channel, and the temperature is significantly reduced.

[0061] 5) Mixing of hot and cold exhaust gas: The cooled exhaust gas and the uncooled exhaust gas are mixed at the outlet of the three-way butterfly valve downstream of the EGR cooler. The opening of the butterfly valve is adjusted according to the engine operating conditions and emission requirements to optimize the mixing ratio.

[0062] 6) Mixing of hot and cold supercharged gas: The cooled supercharged gas and the uncooled supercharged gas are mixed at the outlet of the three-way butterfly valve. The opening of the butterfly valve is adjusted according to the engine operating conditions and ambient temperature to optimize the mixing ratio.

[0063] 7) Exhaust Gas Recirculation: The mixed exhaust gas enters the intake manifold through the EGR valve, mixes with fresh air and enters the combustion chamber again. The opening of the EGR valve is adjusted in real time by the engine control unit (ECU) according to parameters such as engine speed, load, temperature, etc. to control the amount of exhaust gas recirculation.

[0064] 8) Engine intake: After the temperature is adjusted by the three-way butterfly valve, the supercharged mixture and the exhaust gas mixture enter the engine intake manifold after the flow is regulated by the throttle and EGR valve respectively, and finally enter the cylinder for combustion and work.

[0065] In another embodiment, the structure diagram of the control device for the intake air temperature of an ammonia engine provided by the present invention is as follows: Figure 1 and Figure 2 As shown, compared with the traditional diesel engine, an intercooler rear valve S1 (first valve), an intercooler bypass line and its corresponding intercooler bypass valve S2 (second valve), an EGR cooler rear valve S3 (third valve), an EGR bypass line and its corresponding EGR bypass valve S4 (fourth valve) are added. Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, S1 and S2 can be used as two adjustable opening valves set on the intercooler and its bypass pipelines, and can also be used as a three-way adjustable opening valve S12 after the two pipelines are merged. Similarly, S3 and S4 can be used as two adjustable opening valves set on the EGR cooler and its bypass pipelines, and can also be used as a three-way adjustable opening valve S34 after the two pipelines are merged.

[0066] The present invention is not limited to using one three-way butterfly valve or two separate butterfly valves, nor is it limited to whether the three-way butterfly valve is arranged upstream or downstream of the intercooler / EGR cooler. It is also not limited to whether ammonia is injected into the intake port or directly injected into the cylinder, as long as the same function can be achieved.

[0067] The control device for the intake air temperature of an ammonia engine provided by the present invention has the following beneficial effects: Reduce intercooler energy consumption: The intercooler bypass structure is adopted to reduce the energy consumption requirement of the intercooler, and smaller fans and coolers can be used.

[0068] Optimize the combustion process: Increase the intake temperature to make the liquid ammonia vaporize more fully, the mixture mix more evenly, and reduce the risk of wall wetting; at the same time, increase the intake temperature to increase the combustion temperature, increase the combustion speed, and achieve better combustion effect.

[0069] Optimize engine performance: While maintaining low emissions, the engine combustion process is optimized by adjusting the exhaust gas recirculation volume, improving fuel economy and power performance. During the low-load or cold start stage of the engine, the exhaust gas temperature is low. If all the exhaust gas is cooled by the EGR cooler or intercooler, the gas temperature may be too low, which may cause ice or blockage in the intake system. The three-way butterfly valve reduces the proportion of low-temperature gas by increasing the flow of the bypass branch, avoiding the cooling medium from staying in the heat exchanger for a long time, thereby reducing the risk of ice or freezing and protecting the safety of components. In addition, by adjusting the temperature of the mixed gas, the three-way butterfly valve also indirectly affects the temperature and heat capacity of the mixed gas entering the cylinder, which helps to optimize the combustion process and improve the fuel economy and emission performance of the engine.

[0070] Enhanced system flexibility: This technical solution allows flexible adjustment of intake and exhaust gas treatment strategies according to different engine operating conditions and emission requirements.

[0071] The present invention also provides a method for controlling the intake temperature of an ammonia engine, the control method being applied to the above-mentioned control device, such as Figure 7 As shown, the control method includes: S701, the controller controls the first valve, the third valve and the fifth valve to be closed, and controls the second valve to be opened under cold start and low load conditions; S702: The controller adjusts the opening of the fourth valve based on the intake air temperature target value.

[0072] In some embodiments, the method for controlling the intake air temperature of an ammonia engine further includes: The controller controls the third valve and the fifth valve to open and the fourth valve to close under medium and high load conditions, and determines the openings of the first valve and the second valve based on a target intake air temperature of the ammonia engine.

[0073] In some embodiments, the present invention provides a method for controlling the intake temperature of an ammonia engine, such as Figure 8 As shown, including: Working condition judgment: First, the ECU identifies the engine throttle and speed signals to determine whether the engine is operating under cold start and low load conditions or medium to high load conditions.

[0074] Determine target parameters: Determine the required liquid ammonia fuel mass M according to the engine operating conditions (such as speed, load, etc.), and calculate the energy E required for liquid ammonia vaporization. Determine the target engine intake volume V1 and intake temperature target value T3 based on the current engine test experience. Reversely deduce the temperature of the target intake volume due to liquid ammonia vaporization based on E, V1 and T3. The target intake temperature T3 is a function of the liquid ammonia mass: T3 = f (M). Thus, the opening of the intercooler valve S1, intercooler bypass valve S2, EGR valve S5, EGR cooling valve S3, and EGR bypass valve S4 is determined.

[0075] Load judgment: Under cold start and low load conditions, close the intercooler valve S1, fully open the intercooler bypass valve S2 (the corresponding opening of S12 can be the same), close the EGR valve S5 and the EGR cooling valve S3, and based on the mixed temperature T 06 Determine the opening degree K4 of the EGR cooling bypass valve S4 to prevent the engine from being affected by cold start and low load operation due to low ambient temperature.

[0076] Under medium and high load conditions, the EGR cooling valve S3 and the EGR valve S5 are fully opened, the EGR cooling bypass S4 is fully closed, and the opening K2 of the intercooler bypass S2 and the opening K1 of the intercooler valve S1 are adjusted based on the target intake air temperature T3.

[0077] Inlet air temperature model: Using one-dimensional / three-dimensional simulation calculation results and related test data, the mathematical relationship T3=f(S1, S2, S3, S4) between the target engine intake temperature and the two-way / three-way butterfly valve opening (i.e., the EGR cooler bypass / intercooler bypass degree) under different operating conditions is constructed, and the accurate engine intake temperature is estimated using existing sensor data and hardware status.

[0078] Intercooler bypass control: The target intercooler after-temperature T1 is achieved by the opening of the two-way / three-way butterfly valve.

[0079] EGR valve opening judgment: Detect whether the engine has the need to open the EGR valve under the current working conditions. When the engine is under medium and high loads, the EGR valve is opened and needs to enter a closed-loop control strategy with T3 as the control target based on the target value of the mixed intake temperature T3.

[0080] Intercooler bypass & EGR cooler bypass control (closed loop control B): The target intake air temperature T3 is achieved through the opening of the two-way / three-way butterfly valve, PID parameters: CURVE intake air temperature T3 = f (S1, S2, S3, S4).

[0081] Continuous monitoring and adjustment: During the entire process, the system will continuously monitor key parameters such as ambient temperature, intake temperature, temperature after intercooler, temperature after EGR cooler, and dynamically adjust the intercooler valve opening, intercooler bypass opening, EGR cooling valve opening, EGR cooling bypass valve opening and EGR valve opening as needed to ensure that the engine can achieve cold start and stable combustion under various operating conditions, and achieve optimal fuel economy and emission performance.

[0082] The control device and control method for the intake temperature of an ammonia engine provided by the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A control device for the intake air temperature of an ammonia engine, characterized in that: include: An intercooler, the input end of which is connected to the compressor, the output end of which is connected to the input end of the liquid ammonia cylinder, and a first valve is provided in the branch where the intercooler is located; An intercooler bypass branch, the input end of which is connected to the compressor, and the output end of which is connected to the input end of the liquid ammonia cylinder, and a second valve is provided on the intercooler bypass branch; The EGR cooler has an input end connected to the output end of the liquid ammonia cylinder through a fifth valve, and an output end connected to the input end of the liquid ammonia cylinder, and a third valve is provided on the branch where the EGR cooler is located; The EGR bypass branch has an input end connected to the output end of the liquid ammonia cylinder, an output end connected to the input end of the liquid ammonia cylinder, and a fourth valve is provided on the EGR bypass branch; The controller is used to control the first valve, the third valve and the fifth valve to close, and the second valve to open under cold start and low load conditions, and to adjust the opening of the fourth valve based on the intake air temperature target value.

2. The control device for intake air temperature of an ammonia engine according to claim 1, characterized in that: The first valve and the second valve are two valves independent of each other, or constitute a three-way butterfly valve.

3. The control device for intake air temperature of an ammonia engine according to claim 1, characterized in that: The third valve and the fourth valve are two valves independent of each other, or constitute a three-way butterfly valve.

4. The control device for intake air temperature of an ammonia engine according to claim 1, characterized in that: The controller is further used to determine the required liquid ammonia fuel mass based on the operating conditions of the ammonia engine.

5. The control device for intake air temperature of an ammonia engine according to claim 1, characterized in that: The controller is used to determine the energy required for vaporizing the liquid ammonia based on the required liquid ammonia fuel mass, and determine the target intake temperature value of the ammonia engine based on the target intake amount of the ammonia engine, the temperature of the target intake amount reduced by the vaporization of the liquid ammonia, and the energy required for vaporizing the liquid ammonia.

6. The control device for intake air temperature of an ammonia engine according to claim 1, characterized in that: The controller is used for adjusting the opening of the fourth valve by adopting a PID control strategy based on the intake air temperature target value of the ammonia engine and the real-time opening of the fourth valve.

7. The control device for intake air temperature of an ammonia engine according to any one of claims 1 to 6, characterized in that: The controller is also used to control the third valve and the fifth valve to open and the fourth valve to close under medium and high load conditions, and to determine the opening of the first valve and the second valve based on the intake temperature target value of the ammonia engine.

8. The control device for intake air temperature of an ammonia engine according to claim 7, characterized in that: The controller is also used to adjust the opening of the first valve and the second valve by adopting a PID control strategy based on the intake temperature target value of the ammonia engine and the real-time opening of the first valve and the second valve.

9. A method for controlling the intake temperature of an ammonia engine, characterized in that: The control method is applied to the control device according to any one of claims 1 to 8, and the control method includes: The controller controls the first valve, the third valve and the fifth valve to be closed, and controls the second valve to be opened under cold start and low load conditions; The controller adjusts the opening degree of the fourth valve based on the intake air temperature target value.

10. The method for controlling the intake air temperature of an ammonia engine according to claim 9, characterized in that: Also includes: The controller controls the third valve and the fifth valve to open and the fourth valve to close under medium and high load conditions, and determines the openings of the first valve and the second valve based on a target intake air temperature of the ammonia engine.

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