Control device and control method for intake air temperature of methanol compression ignition engine

Abstract

The present invention provides a device and method for controlling the intake air temperature of a methanol compression ignition engine, belonging to the field of engine technology. The control device includes: an intercooler disposed on an intercooler circuit, the intercooler circuit being provided with a first valve; an intercooler bypass branch being provided with a second valve; an EGR cooler disposed on the EGR circuit, the EGR circuit being provided with a third valve and a fifth valve; an EGR bypass branch being provided with a fourth valve; and a controller for controlling one of the first and second valves to open and the other to close under cold start conditions or preset low-load conditions, adjusting the opening of the fourth valve based on an intake air temperature target value, and controlling the third and fifth valves to close. By providing an intercooler bypass, the present invention solves the problem that existing methanol compression ignition engines cannot achieve stable cold start ignition, sustained stable ignition, and stable combustion when burning pure methanol fuel in a low-temperature environment.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a device and method for controlling the intake temperature of a methanol compression ignition engine. Background Art

[0002] Green methanol fuel has been recognized both domestically and internationally as one of the most promising carbon-neutral fuels. Compared to fossil fuels such as gasoline and diesel, methanol has advantages such as high octane number, complete combustion, good anti-knock properties, fast flame propagation speed, and near-zero particulate matter emissions. Methanol engine ignition methods are divided into two categories: compression ignition and spark ignition. Compared to spark ignition methanol engines, compression ignition methanol engines have the advantages of high compression ratio, high thermal efficiency, and cleaner emissions. However, due to the high latent heat of vaporization, low calorific value, and the fact that compression ignition methanol engines are a single-component fuel, when used in internal combustion engines, the poor volatility of methanol will result in a poor mixture quality, making combustion more difficult. External energy stimulation is required for combustion, and the operation is relatively rough, resulting in higher NOx emissions. In addition, there are problems such as difficulty in cold starting and poor responsiveness under acceleration conditions.

[0003] For methanol engines equipped with an EGR (Exhaust Gas Recirculation) system, the primary function of the EGR system cooler is to reduce the temperature of exhaust gas flowing back from the exhaust system to the intake system. This is because during engine operation, some of the burned exhaust gas is reintroduced into the intake system, mixed with fresh air, and then re-entered the cylinder for combustion. However, this exhaust gas is typically at a high temperature. If not cooled, it may cause excessive thermal loads on components such as the engine's intake system, cylinder walls, and pistons, affecting engine performance and life.

[0004] When an engine uses turbocharging or supercharging technology, the supercharger significantly increases intake air pressure, but this also increases intake air temperature. High-temperature air reduces air density, which in turn affects the engine's charging efficiency. An intercooler cools the supercharged air, reducing its temperature and increasing intake air density, allowing the engine to inhale more dense 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 cold environment with low load, 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 operating condition is adopted at this time, that is, all exhaust gases in the EGR branch are 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 this situation, the low-temperature gas in the intake system may encounter water vapor in the cold air and condense into ice, increasing the risk of icing and blockage at the intake. Furthermore, prolonged low-temperature operation may accelerate the material aging process of the EGR system and its related components. For example, the cooler's metal components may be damaged by temperature fluctuations, and seals may harden and lose their elasticity due to low temperatures, thus affecting the EGR system's sealing and durability. In extremely low temperature conditions, the coolant inside the intercooler may ice or freeze, causing damage to the intercooler.

[0007] In addition, under low temperature and low load conditions, the engine's thermal efficiency may be affected. Proper intake air temperature can enable the engine to reach normal operating temperature faster, thereby improving thermal efficiency. It also helps improve the atomization effect of the fuel, promotes the complete combustion of the fuel, and further improves engine performance.

[0008] Therefore, inappropriate EGR cooling and intercooling strategies in low-temperature environments can lead to a series of problems, including intake air icing, increased risk of blockage, and accelerated material aging, all of which can ultimately adversely affect vehicle dynamics. Therefore, in cold climates with low loads, it is necessary to adjust the cooling strategies of both the EGR system and the intercooler system to ensure that the exhaust gas maintains an appropriate temperature when it flows out of the EGR module, thereby preventing the intake air from becoming too cold.

[0009] In summary, existing methanol compression ignition engines have the following problems: when burning pure methanol fuel in a methanol compression ignition engine under low temperature conditions, stable cold start ignition cannot be achieved, and stable ignition and combustion cannot be sustained. Summary of the Invention

[0010] In view of this, it is necessary to provide a control device and control method for the intake temperature of a methanol compression ignition engine to solve the technical problems that the existing methanol compression ignition engine cannot achieve stable cold start ignition, continuous stable ignition and stable combustion when burning pure methanol fuel in a low temperature environment.

[0011] In order to solve the above problems, the present invention provides, on the one hand, a device for controlling the intake air temperature of a methanol compression ignition engine, comprising:

[0012] An intercooler is provided on the intercooling circuit, and a first valve is also provided on the intercooling circuit;

[0013] The intercooler bypass branch is provided with a second valve;

[0014] An EGR cooler is provided on the EGR circuit, and a third valve and a fifth valve are provided on the EGR circuit;

[0015] The EGR bypass branch is provided with a fourth valve;

[0016] a controller configured to control one of the first valve and the second valve to open and the other valve to close under a cold start condition or a preset low load condition, adjust the opening of the fourth valve based on a target intake air temperature, and control the third valve and the fifth valve to close;

[0017] Among them, one end of the intercooler circuit and the intercooler bypass branch are both connected to the compressor, and the other end is connected to the third valve, the fourth valve and the engine. The fourth valve and the fifth valve are also connected to the turbine and the engine.

[0018] In a possible implementation, the first valve and the second valve are two independent valves, or constitute a three-way butterfly valve.

[0019] In a possible implementation, the third valve and the fourth valve are two independent valves, or constitute a three-way butterfly valve.

[0020] In a possible implementation, the controller is further configured to control the second valve and the fourth valve to be closed under preset medium-to-high load conditions.

[0021] In one possible implementation, the controller is further used to control the third valve and the fifth valve to close when the current ambient temperature is less than or equal to the first temperature threshold, and to determine the opening of the fourth valve based on the current ambient temperature; and to determine the opening of the third valve, the fourth valve, and the fifth valve based on the intake air temperature target value when the current ambient temperature is greater than the first temperature threshold.

[0022] In one possible implementation, the controller is further configured to determine the opening of the first valve or the second valve based on the current operating condition of the engine, the ambient temperature, and the target intake temperature under cold start conditions or preset low load conditions.

[0023] In a possible implementation, the controller is further configured to adjust the openings of the first valve, the third valve, and the fifth valve based on a preset control strategy under preset medium and high load conditions.

[0024] On the other hand, the present invention further provides a method for controlling the intake temperature of a methanol compression ignition engine, the control method being applied to any of the control devices described above, the control method comprising:

[0025] The controller controls one of the first valve and the second valve to open and the other valve to close under a cold start condition or a preset low load condition;

[0026] The controller adjusts the opening of the fourth valve based on the intake air temperature target value and controls the third valve and the fifth valve to be closed.

[0027] In one possible implementation, the method for controlling the intake air temperature of a methanol compression ignition engine further includes:

[0028] Under the preset medium and high load conditions, the controller controls the second valve and the fourth valve to be closed.

[0029] In one possible implementation, the method for controlling the intake air temperature of a methanol compression ignition engine further includes:

[0030] When the current ambient temperature is less than or equal to the first temperature threshold, the controller controls the third valve and the fifth valve to close, and determines the opening of the fourth valve based on the current ambient temperature. When the current ambient temperature is greater than the first temperature threshold, the controller determines the opening of the third valve, the fourth valve and the fifth valve based on the intake air temperature target value.

[0031] The beneficial effects of adopting the above-mentioned implementation are as follows: the control device and control method for the intake air temperature of a methanol compression ignition engine provided by the present invention, through the controller, controls one of the first valve and the second valve to open and the other valve to close under cold start conditions or preset low load conditions, and adjusts the opening of the fourth valve based on the intake air temperature target value, and controls the third valve and the fifth valve to close. By opening and closing the valves at five different positions, the cooling medium can be prevented from staying in the intercooler for a long time, thereby reducing the risk of icing or freezing, protecting the safety of the intercooler, reducing the amount of exhaust gas flowing through the EGR cooler or reducing the cooling efficiency of the cooler, so as to ensure that the exhaust gas maintains an appropriate temperature when flowing out of the EGR cooler; through the intercooler bypass, the pressurized air can bypass the intercooler and enter the engine directly, thereby avoiding the problem of too low an intake temperature. When burning pure methanol fuel in the compression ignition engine, stable ignition can be achieved during cold start, and stable ignition and combustion can be maintained. It can also solve problems such as intake air icing, increased clogging risk, and accelerated material aging that may be caused by inappropriate control strategies in low temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] Figure 1 A schematic structural diagram of an embodiment of a device for controlling the intake air temperature of a methanol compression ignition engine provided by the present invention;

[0034] Figure 2 A schematic structural diagram of another embodiment of the device for controlling the intake air temperature of a methanol compression ignition engine provided by the present invention;

[0035] Figure 3 A schematic structural diagram of another embodiment of the device for controlling the intake air temperature of a methanol compression ignition engine provided by the present invention;

[0036] Figure 4 A flow chart of an embodiment of a method for controlling the intake air temperature of a methanol compression ignition engine provided by the present invention;

[0037] Figure 5 This is a flow chart of another embodiment of the method for controlling the intake air temperature of a methanol compression ignition engine provided by the present invention. DETAILED DESCRIPTION

[0038] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0039] In the description of the embodiments of the present application, unless otherwise specified, “a plurality of” means two or more.

[0040] 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 device comprising a series of steps or modules is not necessarily limited to those steps or modules explicitly listed, but may include other steps or modules not explicitly listed or inherent to these processes, methods, products or devices.

[0041] 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.

[0042] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0043] The present invention provides a device and method for controlling the intake air temperature of a methanol compression ignition engine, which are respectively described below.

[0044] like Figure 1 As shown, the present invention provides a device for controlling the intake temperature of a methanol compression ignition engine, comprising:

[0045] An intercooler is provided on the intercooling circuit, and a first valve is also provided on the intercooling circuit;

[0046] The intercooler bypass branch is provided with a second valve;

[0047] An EGR cooler is provided on the EGR circuit, and a third valve and a fifth valve are provided on the EGR circuit;

[0048] The EGR bypass branch is provided with a fourth valve;

[0049] a controller configured to control one of the first valve and the second valve to open and the other valve to close under a cold start condition or a preset low load condition, adjust the opening of the fourth valve based on a target intake air temperature, and control the third valve and the fifth valve to close;

[0050] Among them, one end of the intercooler circuit and the intercooler bypass branch are both connected to the compressor, and the other end is connected to the third valve, the fourth valve and the engine. The fourth valve and the fifth valve are also connected to the turbine and the engine.

[0051] It can be understood that 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 S5.

[0052] The intake air temperature control device for a methanol compression ignition engine, provided herein, aims to optimize intake air temperature and efficiency during low-temperature cold-start and low-load engine conditions. This control device precisely controls the exhaust gas temperature and flow rate entering the intake manifold by allowing a portion of the exhaust gas to be cooled by the EGR cooler before passing through the EGR valve (fifth valve), while another portion bypasses the EGR cooler via a bypass branch. The exhaust gas is then mixed upstream and downstream of the EGR cooler via two-way and three-way butterfly valves (third and fourth valves). Similarly, this solution precisely controls the temperature and flow rate of the supercharged gas entering the intake manifold by allowing a portion of the supercharged gas to be cooled by the intercooler before passing through the throttle valve, while another portion bypasses the intercooler via a bypass branch. The combined action of these two mechanisms enables precise control of the overall engine intake air temperature and flow rate.

[0053] Working condition judgment:

[0054] First, the engine control unit (ECU) identifies the engine throttle, speed, and engine water temperature signals to determine whether the engine is operating in a cold start, low load, or medium to high load condition.

[0055] Among them, the target limit of the engine water temperature in the cold start condition is T0℃. If the engine water temperature signal is ≤T0℃ and the engine speed signal is less than the engine idle speed, the cold start condition is entered; if the engine water temperature signal is ≤T0℃ and the engine throttle signal is less than 25% of the full throttle, the low load condition is entered; if the engine water temperature signal is greater than T0℃ and the engine throttle signal is greater than 25% of the full throttle, the medium and high load condition is entered.

[0056] If the engine enters medium to high load conditions, the engine enters normal operating state, the intercooler bypass and EGR cooling bypass are closed, and the EGR valve is determined based on the engine's existing control strategy to ensure stable engine operation and normal emissions.

[0057] The working process of the control device for the intake air temperature of a methanol compression ignition engine is as follows:

[0058] 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.

[0059] 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 passes through the bypass branch.

[0060] 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.

[0061] 4) Charged gas cooling: The charged gas entering the intercooler exchanges heat with the external environment through the cooling channel, and the temperature is significantly reduced.

[0062] 5) Mixing of hot and cold exhaust gases: Cooled and uncooled exhaust gases 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 engine operating conditions and emission requirements to optimize the mixing ratio.

[0063] 6) Mixing of hot and cold supercharged gases: Cooled supercharged gases and uncooled supercharged gases 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.

[0064] 7) Exhaust Gas Recirculation: Mixed exhaust gas enters the intake manifold through the EGR valve, where it mixes with fresh air and re-enters the combustion chamber. The EGR valve opening is adjusted in real time by the engine control unit (ECU) based on engine speed, load, temperature, and other parameters to control the amount of exhaust gas recirculated.

[0065] 8) Engine intake: After the temperature is adjusted by the three-way butterfly valve, the supercharged mixture and the exhaust gas mixture are respectively regulated by the throttle valve and the EGR valve to enter the engine intake manifold, and finally enter the cylinder for combustion and work.

[0066] In one embodiment, the first valve and the second valve are two independent valves, or constitute a three-way butterfly valve.

[0067] In one embodiment, the third valve and the fourth valve are two independent valves, or constitute a three-way butterfly valve.

[0068] It is understood that the three-way butterfly valve used in the present invention comprises a valve body, a drive shaft, three valve discs (valve disc 1, valve disc 2, and valve disc 3), a motor, and a cooling water jacket disposed within the valve body. The valve body is internally provided with three independent airflow channels, each corresponding to a valve disc. The valve discs are connected to the motor via a drive shaft for synchronous control. Valve discs 2 and 3 have the same phase angle, but are arranged 90° out of phase with valve disc 1. This ensures that, by default, the valve disc in channel 1 is fully open, while the valve discs in channels 2 and 3 are fully closed.

[0069] like Figure 2 As shown, compared with the traditional diesel engine, the present invention adds 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). Figure 3As shown, S1 and S2 can be used as two adjustable opening valves set on the intercooler and its bypass pipelines, or as a three-way adjustable opening valve S12 after the two pipelines merge, that is, a three-way butterfly valve. Figure 4 As shown, S3 and S4 can be used as two adjustable opening valves provided on the EGR cooler and its bypass pipeline, or as a three-way adjustable opening valve S34 after the two pipelines merge, that is, a three-way butterfly valve.

[0070] The present invention is not limited to using one three-way butterfly valve or two separate butterfly valves, nor is it limited to being arranged upstream or downstream of the intercooler / EGR intercooler, as long as the same function can be achieved.

[0071] Single drive shaft control: One drive shaft is used to simultaneously control the opening and closing of three valve plates, driven by a single motor, which simplifies the structure, reduces costs and improves reliability.

[0072] 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 is cooled or the low-temperature gas is kept warm, thus expanding the application range of the valve.

[0073] Flexible opening adjustment: Through the precise control of the motor, all valves can be adjusted to any opening between fully closed and fully open, including half-open state, to meet the gas flow requirements under different working conditions.

[0074] Variable channel diameter: According to actual usage, channels of different diameters can be selected to optimize gas flow resistance and improve throttling efficiency.

[0075] In one embodiment, the controller is further configured to control the second valve and the fourth valve to be closed under preset medium and high load conditions.

[0076] In one embodiment, the controller is further used to control the third valve and the fifth valve to close when the current ambient temperature is less than or equal to the first temperature threshold, and to determine the opening of the fourth valve based on the current ambient temperature; and to determine the opening of the third valve, the fourth valve and the fifth valve based on the intake air temperature target value when the current ambient temperature is greater than the first temperature threshold.

[0077] In one embodiment, the controller is further configured to determine the opening of the first valve or the second valve based on the current operating condition of the engine, the ambient temperature, and the target intake air temperature under cold start conditions or preset low load conditions.

[0078] In one embodiment, the controller is further configured to adjust the openings of the first valve, the third valve, and the fifth valve based on a preset control strategy under preset medium and high load conditions.

[0079] In some embodiments, a device for controlling the intake air temperature of a methanol compression ignition engine includes:

[0080] 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).

[0081] 2) EGR bypass branch: provides a channel for uncooled exhaust gas to bypass the EGR cooler.

[0082] 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.

[0083] 4) Intercooler bypass branch: provides a channel for uncooled pressurized gas to bypass the intercooler.

[0084] 5) Three-way Butterfly Valve: Installed downstream / upstream of the EGR cooler and intercooler, it has two chambers: one for regulating the mixture ratio of cooled and uncooled exhaust gas, and the other for regulating the mixture ratio of cooled and uncooled boost gas. The degree of opening of the butterfly valve determines the mixture ratio of the hot and cold gases. Features of a three-way butterfly valve include a valve body made of corrosion-resistant, high-temperature materials to withstand the high-temperature and high-pressure environments of exhaust and boost gas. The butterfly disc, as a control element, rotates to adjust the opening of the channel, thereby regulating the exhaust gas flow. The edge of the butterfly disc is typically specially treated to reduce fluid resistance and improve sealing performance. A sealing ring or gasket is placed between the butterfly disc and the valve seat to effectively prevent exhaust gas leakage when closed. The butterfly valve's actuator (e.g., electric, pneumatic, or hydraulic) receives signals from the engine control unit (ECU) to precisely control the rotation angle of the butterfly disc, achieving precise regulation of exhaust flow.

[0085] 6) EGR valve: Located after the three-way butterfly valve, it controls the amount of mixed exhaust gas entering the intake manifold.

[0086] 7) Throttle: Located after the three-way butterfly valve, it controls the amount of mixed pressurized gas entering the intake manifold.

[0087] The three-way butterfly valve design employed in this invention offers a high degree of integration and is more compact, enabling easier integration with other system components (such as the EGR cooler, EGR valve, and intercooler), significantly reducing the length and complexity of the bypass piping. This not only helps conserve 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 overall system reliability and maintainability. By tightly integrating the three-way butterfly valve with the EGR cooler and intercooler circuits, a fully functional, compact, integrated module is formed. This modular design simplifies installation and improves overall system performance and reliability. It also facilitates subsequent maintenance and replacement, as the entire module can be disassembled and assembled as a single unit.

[0088] While two traditional solenoid valves can function in an EGR bypass system, their size and shape may limit tight integration with other components, impacting the overall system layout and efficiency. Traditional solenoid valves may require additional piping and fittings to connect the EGR cooler and EGR valve, increasing system complexity and footprint. The typically loose connection between traditional solenoid valves and the EGR cooler makes it difficult to achieve a high degree of modularity. This can lead to increased time and labor required during installation, maintenance, and replacement.

[0089] 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 high-temperature and low-temperature gases at the same time, broadening its scope of application. Low gas flow resistance: By adjusting the channel diameter and the valve plate opening, precise control of gas flow resistance can be achieved, thereby improving throttling efficiency.

[0090] This is crucial 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.

[0091] In addition, the use of pure methanol fuel eliminates the need for dual fuel, or the addition of combustion aids, improvers, or emulsifiers. Compression ignition eliminates the need for spark plugs, glow plugs, or heaters to assist in heating, solving the problem of methanol cold starts. There is no need to crack or evaporate methanol, and there is no need for additional cracking and heating equipment, which would increase cost and weight.

[0092] Improve emission performance: Effectively reduce NOx emissions by precisely controlling the mixing ratio and recirculation volume of exhaust gases.

[0093] Optimizing Engine Performance: While maintaining low emissions, the engine's combustion process is optimized by adjusting the exhaust gas recirculation rate, improving fuel economy and power performance. During low engine load or cold start phases, exhaust gas temperatures are low. If all exhaust gas passes through the EGR cooler or intercooler, the gas temperature may be too low, leading to ice formation or blockage in the intake system. The three-way butterfly valve increases the flow rate of the bypass branch, reducing the proportion of low-temperature gas and preventing the cooling medium from remaining in the heat exchanger for a long time, thereby reducing the risk of ice or freezing and protecting component safety. Furthermore, by regulating the temperature of the mixed gas, the three-way butterfly valve indirectly affects the temperature and heat capacity of the mixed gas entering the cylinder, thereby helping to optimize the combustion process and improve the engine's fuel economy and emissions performance.

[0094] 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.

[0095] Compared with diesel, methanol has a higher octane number, complete combustion, good anti-knock performance, and fast flame propagation speed. Therefore, after controlling the stable start-up and stable combustion of methanol under low temperature conditions, methanol compression ignition can enable the engine to achieve higher thermal efficiency than diesel.

[0096] Methanol combustion can greatly reduce the emissions of NOx, PM and volatile organic compounds, and is an effective alternative energy source for achieving carbon neutrality goals.

[0097] Methanol is cheaper than diesel and has lower manufacturing and transportation costs, making it a better choice for users.

[0098] The present invention also provides a method for controlling the intake temperature of a methanol compression ignition engine, which is applied to any of the control devices described above. Figure 4 As shown, the control method includes:

[0099] S401: Under a cold start condition or a preset low load condition, the controller controls one of the first valve and the second valve to open and the other valve to close;

[0100] S402 : The controller adjusts the opening of the fourth valve based on the intake air temperature target value, and controls the third valve and the fifth valve to be closed.

[0101] In one embodiment, the method for controlling the intake air temperature of a methanol compression ignition engine further includes:

[0102] Under the preset medium and high load conditions, the controller controls the second valve and the fourth valve to be closed.

[0103] In one embodiment, the method for controlling the intake air temperature of a methanol compression ignition engine further includes:

[0104] When the current ambient temperature is less than or equal to the first temperature threshold, the controller controls the third valve and the fifth valve to close, and determines the opening of the fourth valve based on the current ambient temperature. When the current ambient temperature is greater than the first temperature threshold, the controller determines the opening of the third valve, the fourth valve and the fifth valve based on the intake air temperature target value.

[0105] In some embodiments, as Figure 5 As shown, the method for controlling the intake air temperature of a methanol compression ignition engine includes:

[0106] Ambient temperature judgment:

[0107] Under cold start and low load conditions, the system detects the current ambient temperature T amb .

[0108] If T amb ≤ 0°C, perform special condition processing: close the intercooler valve S1, open the intercooler bypass valve S2 (the corresponding opening of S12 can be the same), and ensure that the engine intake temperature is higher than the target temperature T 04 , to prevent the engine from being affected by the low ambient temperature and affecting the engine cold start and low load operation; at the same time, the EGR valve S5 and the EGR cooling valve S3 are closed, and the EGR cooling bypass valve is opened, further supporting the engine cold start and low load operating temperature.

[0109] If 0℃<T amb ≤T1℃, close the intercooler valve S1, open the intercooler bypass valve S2 (the corresponding opening of S12 can be the same), close the EGR valve S5 and EGR cooling valve S3, and open the EGR cooling bypass valve. 04 As well as the engine emission requirements, confirm the EGR cooling bypass valve opening K2.

[0110] If T amb >T1℃, open the intercooler valve S1 and close the intercooler bypass valve S2 (the corresponding opening of S12 can be the same), and the engine intake temperature is higher than the target temperature T 04 As well as the engine emission requirements, the EGR cooling valve S3 opening K3, the EGR valve S5 opening K4 and the EGR cooling bypass valve S4 opening K5 are determined.

[0111] Determine target parameters:

[0112] Determine the target value of engine intake temperature T based on current engine test experience 04 , according to the operating conditions (such as speed, load, etc.) and ambient temperature T amband the intake air temperature target value T 04 Determine whether the intercooler valve S1 and the intercooler bypass valve S2 are open or closed.

[0113] Inlet air temperature model:

[0114] Using one-dimensional / three-dimensional simulation results and relevant test data, the mathematical relationship between the 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. 04 =f(S1, S2, S3, S4), and estimate the exact temperature of the engine intake air using the existing sensor data and hardware status.

[0115] Intercooler bypass control:

[0116] Achieve target intercooler after-temperature T by opening the two-way / three-way butterfly valve 03 .

[0117] EGR valve opening judgment:

[0118] Check whether the engine has EGR valve opening requirements under the current working conditions. If T amb When the temperature is higher than T1℃, the EGR valve opens and the intake air temperature target value T 04 , enter the T 04 A closed-loop control strategy for the control target.

[0119] Intercooler bypass & EGR cooler bypass control (closed loop control B):

[0120] Achieve target intake air temperature T by opening the two-way / three-way butterfly valve 04 , PID parameters: CURVE intake air temperature T 04 =f(S1, S2, S3, S4).

[0121] Continuous monitoring and adjustment:

[0122] During the entire process, the system will continuously monitor key parameters such as ambient temperature, intake temperature, intercooler temperature, and EGR cooler temperature, 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.

[0123] The above is a detailed introduction to the control device and control method for the intake air temperature of a methanol compression ignition engine provided by the present invention. 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 and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A control device for the intake air temperature of a methanol compression ignition engine, characterized in that: include: An intercooler is provided on the intercooling circuit, and a first valve is also provided on the intercooling circuit; The intercooler bypass branch is provided with a second valve; An EGR cooler is provided on the EGR circuit, and a third valve and a fifth valve are provided on the EGR circuit; The EGR bypass branch is provided with a fourth valve; a controller configured to control one of the first valve and the second valve to open and the other valve to close under a cold start condition or a preset low load condition, adjust the opening of the fourth valve based on a target intake air temperature, and control the third valve and the fifth valve to close; Among them, one end of the intercooler circuit and the intercooler bypass branch are both connected to the compressor, and the other end is connected to the third valve, the fourth valve and the engine. The fourth valve and the fifth valve are also connected to the turbine and the engine.

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

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

4. The control device for intake air temperature of a methanol compression ignition engine according to claim 1, characterized in that: The controller is also used to control the second valve and the fourth valve to be closed under preset medium and high load conditions.

5. The control device for intake air temperature of a methanol compression ignition engine according to claim 1, characterized in that: The controller is also used to control the third valve and the fifth valve to close when the current ambient temperature is less than or equal to the first temperature threshold, and to determine the opening of the fourth valve based on the current ambient temperature; when the current ambient temperature is greater than the first temperature threshold, to determine the opening of the third valve, the fourth valve and the fifth valve based on the intake temperature target value.

6. The control device for intake air temperature of a methanol compression ignition engine according to claim 1, characterized in that: The controller is further used to determine the opening of the first valve or the second valve based on the current operating condition of the engine, the ambient temperature and the intake air temperature target value under cold start conditions or preset low load conditions.

7. The control device for intake air temperature of a methanol compression ignition engine according to any one of claims 1 to 6, characterized in that: The controller is further used to adjust the opening of the first valve, the third valve and the fifth valve based on a preset control strategy under preset medium and high load conditions.

8. A method for controlling the intake air temperature of a methanol compression ignition engine, characterized in that: The control method is applied to the control device according to any one of claims 1 to 7, and the control method includes: The controller controls one of the first valve and the second valve to open and the other valve to close under a cold start condition or a preset low load condition; The controller adjusts the opening of the fourth valve based on the intake air temperature target value and controls the third valve and the fifth valve to be closed.

9. The method for controlling the intake air temperature of a methanol compression ignition engine according to claim 8, characterized in that: Also includes: Under the preset medium and high load conditions, the controller controls the second valve and the fourth valve to be closed.

10. The method for controlling the intake air temperature of a methanol compression ignition engine according to claim 8 or 9, characterized in that: Also includes: When the current ambient temperature is less than or equal to the first temperature threshold, the controller controls the third valve and the fifth valve to close, and determines the opening of the fourth valve based on the current ambient temperature. When the current ambient temperature is greater than the first temperature threshold, the controller determines the opening of the third valve, the fourth valve and the fifth valve based on the intake air temperature target value.

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