Methanol engine, anti-freezing system and control method

Abstract

The invention relates to a methanol engine which comprises an engine body, multiple air cylinders are arranged in the engine body, and each air cylinder corresponds to at least two air inlet valves; the air inlet manifold is arranged on the engine body, and the air inlet manifold comprises a plurality of air inlet branch pipes communicating with air cylinders in a one-to-one correspondence mode. And the at least two methanol oil injectors are arranged on the air inlet branch pipe, and the injection direction of each methanol oil injector directly faces one air inlet valve of the air cylinder. By the adoption of the structural design that the two oil sprayers directly face the air inlet valve, the problem that in the scheme of a single oil sprayer, fuel spray impacts a valve rod or falls into the position between the two valves, and consequently the wall is wetted is fundamentally solved, and hot air provided by an air compressor is introduced into an air inlet pipeline under the working condition of cold start; and through the synergistic effect of the two components, the forming quality of combustible mixed gas at the low temperature is fundamentally improved, and the cold start reliability of a methanol engine is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of methanol engine, in particular to a methanol engine, an anti-freezing system and a control method. BACKGROUND

[0002] With the improvement of energy diversification and environmental protection requirements, methanol as a clean fuel is increasingly concerned in the field of engine. However, due to the high latent heat of vaporization and large viscosity at low temperature of methanol fuel, the cold start performance of engine in low temperature environment is significantly deteriorated, which is specifically manifested as follows: the methanol is difficult to form combustible mixture due to poor atomization and vaporization effect in the intake port and cylinder, resulting in difficult start or even unable to start.

[0003] In order to solve the above problems, Chinese patent CN108979925A discloses a methanol engine and vehicle, which is provided with a methanol fuel injector and a gasoline cold start fuel injector at the intake manifold of each cylinder, and the cold start is assisted by injecting gasoline. However, the prior art scheme only provides one methanol fuel injector for each cylinder, and the injection position cannot simultaneously consider two intake valves, which causes the methanol and gasoline spray to be easily injected into the low temperature area between the two valves, resulting in fuel wet wall, inaccurate actual fuel injection amount control, and seriously hindering the atomization and mixing effect of fuel in cold start condition. In addition, the scheme needs to additionally configure a complete gasoline cold start system, which not only makes the engine structure complicated and occupies a large space, but also significantly increases the manufacturing cost and maintenance cost of the vehicle. Therefore, there is an urgent need in the field for a new technical scheme which does not depend on gasoline assistance, has simple system structure, low cost, and can effectively ensure the atomization and mixing effect of methanol fuel in cold start condition to solve the defects of the prior art. SUMMARY

[0004] The present application provides a methanol engine, an anti-freezing system and a control method to solve the above problems.

[0005] In a first aspect, the embodiments of the present application provide a methanol engine, comprising: an engine body, which is provided with a plurality of cylinders, each of the cylinders corresponding to at least two intake valves; an intake manifold, which is arranged on the engine body, and the intake manifold comprises a plurality of intake branch pipes corresponding to the cylinders one by one; at least two methanol fuel injectors, which are arranged on the intake branch pipes, and the injection direction of each of the methanol fuel injectors is opposite to one of the intake valves of the cylinder.

[0006] In combination with the first aspect, in an implementation manner, the intake branch pipe is provided with a turbulence structure.

[0007] With the first aspect, in an implementation, the spoiler structure is a protrusion arranged on the wall surface of the intake branch flow channel.

[0008] With the second aspect, the application provides a cold start system based on a methanol engine, comprising: An air compressor for providing compressed air; An air storage pipeline for storing compressed air for vehicle braking, the air storage pipeline being connected with the air compressor, and the air storage pipeline being provided with a switching assembly; An air intake pipeline connected with an intake manifold for providing air required for combustion of the engine body; A heating pipeline, an air inlet end of which is connected with an air outlet of the air compressor through the switching assembly, and an air outlet end of which is in communication with the air intake pipeline; A first detection assembly for acquiring coolant temperature data of the engine body and ambient temperature data; A control assembly configured to control the switching assembly to guide high-temperature compressed air generated by the air compressor to the heating pipeline to increase the air intake temperature based on the coolant temperature data and the ambient temperature data acquired by the first detection assembly.

[0009] With the second aspect, in an implementation, the application further comprises: A coolant loop integrated in the interior of the air compressor, the coolant loop being in communication with a cooling system of the engine body.

[0010] With the second aspect, in an implementation, the switching assembly is a three-way electromagnetic valve.

[0011] With the second aspect, in an implementation, the air intake pipeline is further provided with a second detection assembly for detecting the temperature of the gas and a heating assembly.

[0012] With the second aspect, in an implementation, the application further comprises: An air supply pipeline, an air inlet end of the air supply pipeline being in communication with the air intake pipeline, and an air outlet end of the air supply pipeline being connected with an air inlet of the air compressor.

[0013] With the third aspect, the application provides a control method of a cold start system based on a methanol engine, comprising the following steps: Based on acquired coolant temperature data of the engine body and ambient temperature data, it is determined whether the engine body is in a cold start working condition; If the engine body is in the cold start working condition, the switching assembly is controlled to guide high-temperature compressed air generated by the air compressor to the heating pipeline to increase the air intake temperature.

[0014] In combination with the third aspect, in an implementation, the cold starting system of the methanol engine further comprises: the intake pipe is further provided with a second detection component for detecting the temperature of the gas and a heating component. The control of the conversion component to guide the high-temperature compressed air generated by the air compressor to the heating pipe to increase the temperature of the intake gas further comprises obtaining the temperature data of the gas in the intake pipe; determining whether the temperature data of the gas meets the preset requirement; If not, the heating component is controlled to start until the temperature data of the gas meets the preset requirement.

[0015] The technical scheme provided by the embodiments of the present application has the following beneficial effects: 1. By adopting the structure design of the double fuel injectors directly opposite the intake valves, precise fuel injection is realized, the problem of wet wall caused by the fuel spray impacting the valve stem or falling into the middle of the two valves in the single fuel injector scheme is fundamentally solved, the initial atomization quality of the methanol is ensured from the source, and by introducing the hot gas provided by the air compressor into the intake pipe under the cold starting condition, the necessary and sufficient heat for the evaporation and atomization of the methanol is provided, the formation quality of the combustible mixture under low temperature is fundamentally improved through the synergistic effect of the two, and the cold starting reliability of the methanol engine is ensured.

[0016] 2. The air compressor for providing heat is the inherent equipment of the vehicle itself, without the need for additional large independent heating devices, and only the existing resources can be utilized through pipe design, which not only greatly simplifies the system structure, saves the layout space, but also effectively reduces the vehicle manufacturing cost and maintenance cost.

[0017] 3. By connecting the cooling liquid circuit with the cooling system of the engine, the hot gas generated by the air compressor can heat the engine coolant at the same time, thereby the temperature of the engine body can be quickly increased, and the atomization and mixing effect of the methanol fuel under the cold starting condition is further ensured, and the success rate of the cold starting of the methanol engine is improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical scheme in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating any creative labor.

[0019] Figure 1 It is a schematic diagram of the methanol fuel injector of the present application; Figure 2 It is a schematic diagram of the turbulence structure of the present application; Figure 3Another schematic view of the methanol fuel injector of the present application; Figure 4 Schematic view of the cold start system of the present application.

[0020] In the figure: 1, engine body; 101, intake valve; 102, intake branch pipe; 103, methanol fuel injector; 2, air compressor; 3, air storage pipeline; 4, conversion assembly; 5, intake pipeline; 6, heating pipeline; 7, control assembly; 8, cooling liquid circuit; 9, air supply pipeline; 10, heating assembly; 11, dryer; 12, air storage cylinder; 13, air filter; 14, turbocharger; 15, intercooler. DETAILED DESCRIPTION

[0021] In order to make the person skilled in the art better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor are within the scope of protection of the present application.

[0022] Embodiment one: Please refer to Figure 1 and Figure 3 , the embodiment one of the present application provides a methanol engine, comprising: An engine body 1, which is provided with a plurality of cylinders, and each cylinder corresponds to at least two intake valves 101; An intake manifold, which is arranged on the engine body 1, and the intake manifold comprises a plurality of intake branch pipes 102 corresponding to the cylinders one by one, and the intake branch pipe 102 is provided with a turbulence structure, which is a protrusion arranged on the flow channel wall surface of the intake branch pipe 102; Specifically, in order to optimize the air flow and fuel mixing, a turbulence structure is integrally formed or processed on the inner wall flow channel of each intake branch pipe 102. In the embodiment, as shown in the figure, Figure 2 the turbulence structure is specifically a protrusion arranged on the flow channel wall surface. These protrusions can be hemispherical, rib-shaped or other irregular shapes. The core function is to break the laminar flow when the air flows through, generate controllable vortex, thereby promoting the preliminary mixing of the injected methanol fuel and air, and improving the mixing effect; At least two methanol fuel injectors 103, which are arranged on the intake branch pipe 102, and the injection direction of each methanol fuel injector 103 is directly opposite to one intake valve 101 of the cylinder; The number of methanol injectors 103 corresponds to the number of intake valves 101, which avoids the problem of incomplete fuel spray coverage in the single-injector scheme, which is prone to spray into the low-temperature area between two valves, resulting in wet wall, significantly reduces the wall adhesion loss of methanol fuel, and fully utilizes the secondary atomization effect of the high-temperature intake valve 101 surface, which can break the methanol droplets into finer mist droplets, thereby greatly improving the final atomization quality and the homogenization degree of the mixture.

[0023] Embodiment two: Please refer to Figure 4 Based on the same technical concept as embodiment one, the application also provides a cold start system based on the methanol engine in embodiment one, which comprises: The air compressor 2 is preferably an electric air compressor inherent to the vehicle, which is mainly used to provide compressed air for the vehicle braking system, and in this system, its function is extended and used as an efficient heating device during cold start; The air storage pipeline 3 is used to store compressed air for vehicle braking, and specifically, the air inlet end to the air outlet end is provided with a conversion assembly 4, a dryer 11 and an air cylinder 12 in sequence; The conversion assembly 4 is preferably a three-way electromagnetic valve; The air inlet pipeline 5 is connected with the intake manifold and is used to provide air required for combustion of the engine body 1, and specifically, the air inlet end to the air outlet end is provided with an air cleaner 13, a turbocharger 14 and an intercooler 15 in sequence, and the air inlet pipeline 5 is also provided with a gas supply pipeline 9, the air outlet end of which is connected with the air inlet of the air compressor 2, for providing air required for the operation of the air compressor 2; The heating pipeline 6 is connected with the air outlet of the air compressor 2 through the conversion assembly 4 at the air inlet end, and is in communication with the air inlet pipeline 5 at the air outlet end; Specifically, when the engine body 1 is started under cold start operation, the hot air generated by the air compressor 2 can be made to enter the inside of the air inlet pipeline 5 through the heating pipeline 6 by controlling the conversion assembly 4, thereby increasing the air inlet temperature, which provides the necessary and sufficient heat for the evaporation and atomization of methanol, improves the formation quality of the combustible mixture at low temperature, and ensures the cold start reliability of the methanol engine; The cooling liquid circuit 8 is integrated in the inside of the air compressor 2, and the cooling liquid circuit 8 is in communication with the cooling system of the engine body 1, so that the heat generated by the air compressor 2 during operation can be directly transmitted to the engine cooling liquid flowing through the circuit, thereby actively heating the cooling liquid; By connecting the cooling liquid circuit 8 with the cooling system of the engine body 1, the hot gas generated by the air compressor 2 can heat the engine cooling liquid simultaneously, thereby quickly raising the temperature of the engine body 1, further ensuring the atomization and mixing effect of the methanol fuel in the cold start condition, and improving the success rate of the cold start of the methanol engine; It is worth noting that the present application fully utilizes the working condition characteristics that the load rate of the air compressor 2 is usually lower than 25% and the cold start time of the methanol engine is short, and the system only uses part or all of the compressed air generated by the air compressor 2 for heating in a very short time, usually one to two minutes, at the beginning of the cold start, through the conversion assembly 4, since the process takes a short time and the gas consumption is relatively small compared to the capacity of the gas cylinder 12, and the air compressor 2 itself has the ability to quickly supplement air, therefore, this operation is within the design redundancy of the air compressor 2 and the gas storage pipeline 3, which can completely ensure the safety of the brake system gas storage pressure and will not have any negative impact on the vehicle braking safety.

[0024] The first detection assembly includes a first temperature sensor for obtaining the cooling liquid temperature data of the engine body 1 and a second temperature sensor for obtaining the ambient temperature; The control assembly 7, which is preferably the original engine electronic control unit ECU of the vehicle, is configured to control the conversion assembly 4 to guide the high-temperature compressed air generated by the air compressor 2 to the heating pipeline 6 to raise the intake air temperature based on the cooling liquid temperature data and the ambient temperature data obtained by the first detection assembly; In the present embodiment, the intake pipeline 5 is also provided with a second detection assembly for detecting the gas temperature and a heating assembly 10, which is preferably a PTC electric heater; The second detection assembly is also a temperature sensor, specifically: When the air compressor 2 is running in the cold start, the total heat load generated by the air compressor 2 is relatively fixed, and this part of heat will be distributed to two paths at the same time: The first aspect is to bring heat into the intake pipeline 5 through the heating pipeline 6 by compressed air, for raising the intake air temperature; The second aspect is to transfer the waste heat to the engine cooling liquid through the cooling liquid circuit 8 integrated inside, for raising the engine body temperature; And in the extremely cold working conditions or the initial stage of cold start, due to the extremely low ambient temperature and engine body 1 temperature, the heat generated by the air compressor 2 may not be sufficient to meet the two major needs of intake heating and coolant heating at the same time, so a second detection component is provided to directly obtain the temperature of the gas entering the intake pipe 5, when the temperature is sufficient, it indicates that the heat provided by the air compressor 2 is sufficient, and the heating assembly 10 will remain closed, the system runs in the most energy-saving way, when the temperature is not enough, it can improve the temperature of the final intake by opening the heating assembly 10 to heat again, to ensure the heat environment of methanol fuel atomization.

[0025] Example three: Based on the same technical concept as example two, the application also provides a control method based on the cold start system of the methanol engine in example two, which includes the following steps: S1, based on the obtained coolant temperature data of the engine body 1 and the ambient temperature data, judge whether the engine body 1 is in cold start working condition; Specifically, it is a logical judgment process executed by the control assembly 7, the first detection assembly continuously or intermittently sends the engine coolant temperature signal and the ambient temperature signal to the ECU.

[0026] The ECU has two temperature thresholds for working condition judgment preset inside: The first set temperature value: it represents the coolant temperature threshold when the engine has not reached the normal working temperature, usually set between 40℃ to 60℃, which indicates that the engine body 1 is still in the cold state, and in this embodiment, it is preferably 40℃; The second set temperature value: it represents the ambient temperature threshold of low temperature environment, usually set between 0℃ to 10℃, this temperature value indicates that the external environment is sufficient to cause the methanol atomization difficult, and in this embodiment, it is preferably 5℃; If the obtained coolant temperature data is lower than the first set temperature value, and the ambient temperature data is lower than the second set temperature value, it means that the vehicle is in cold start working condition at this time; S2, if the engine body 1 is in cold start working condition, the control switching assembly 4 will guide the high temperature compressed air generated by the air compressor 2 to the heating pipe 6 to raise the intake temperature.

[0027] Specifically, the control assembly 7 will execute a series of consecutive control instructions when it determines that the engine body 1 is in cold start working condition, as follows: The control assembly 7 first sends a start signal to the air compressor 2, if the air compressor 2 is in running state for brake system, the control assembly 7 will send an electric control signal to the switching assembly 4 to drive the valve core to act, and switch its internal flow channel from the default communication gas storage pipe 3 to the communication heating pipe 6; After the switch is completed, the high-temperature compressed air generated by the air compressor 2 is directly delivered to the intake pipeline 5 of the engine through the heating pipeline 6, and the high-temperature gas is rapidly mixed with the fresh air in the intake pipeline 5, so as to realize rapid and active heating of the intake air; During the whole heating process, the control assembly 7 continuously monitors the temperature data in the intake pipeline 5 through the second detection assembly, and if the temperature data in the intake pipeline 5 is lower than the third temperature threshold, the control assembly 7 controls the heating assembly 10 to start until the temperature data in the intake pipeline 5 reaches the third temperature threshold.

[0028] The third temperature threshold is a calibrated intake temperature target value, which is usually set above a temperature ensuring that the methanol fuel can be well atomized and condensation does not occur, and is preferably 60℃ in the embodiment, which provides crucial temperature guarantee for sufficient atomization and formation of homogeneous mixture of the methanol fuel, thereby significantly improving the cold start success rate and reliability of the methanol engine in a low-temperature environment.

[0029] In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, and it can be the communication between two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0030] It should be noted that in the present application, relational terms such as "first" and "second" and the like are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0031] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to these embodiments without departing from the spirit and scope of the application. It is intended that the scope of the application should not be limited by the particular representative embodiments described above.

Claims

1. A methanol engine characterized by comprising: The engine body (1) is internally provided with a plurality of cylinders, each of the cylinders corresponding to at least two intake valves (101); an intake manifold is arranged on the engine body (1), the intake manifold comprising a plurality of intake branch pipes (102) corresponding to the cylinders one by one; at least two methanol injectors (103) are arranged on the intake branch pipes (102), and the injection direction of each of the methanol injectors (103) is directly opposite to one of the intake valves (101) of the cylinder. The intake branch pipe (102) is internally provided with a spoiler structure. The spoiler structure is a protrusion arranged on the wall surface of the flow channel of the intake branch pipe (102). The air compressor (2) is used to provide compressed air; an air storage pipeline (3) is used to store compressed air for vehicle braking, the air storage pipeline (3) is connected with the air compressor (2), and the air storage pipeline (3) is internally provided with a switching assembly (4); an air inlet pipeline (5) is connected with the intake manifold and is used to provide air required for combustion of the engine body (1); a heating pipeline (6) has its air inlet end connected with the air outlet of the air compressor (2) through the switching assembly (4) and its air outlet end communicated with the air inlet pipeline (5); a first detection assembly is used to acquire coolant temperature data and environmental temperature data of the engine body (1); and a control assembly (7) is configured to control the switching assembly (4) to guide high-temperature compressed air generated by the air compressor (2) to the heating pipeline (6) to increase the air inlet temperature based on the coolant temperature data and the environmental temperature data acquired by the first detection assembly.

2. The methanol engine according to claim 1, characterized by Further comprising: a coolant circuit (8) integrated in the interior of the air compressor (2), the coolant circuit (8) being communicated with the cooling system of the engine body (1).

3. The methanol engine according to claim 2, characterized by The switching assembly (4) is a three-way electromagnetic valve.

4. A cold start system for a methanol engine based on the engine of claim 1, characterized by The air inlet pipeline (5) is further internally provided with a second detection assembly for detecting the temperature of the gas and a heating assembly (10). Further comprising: an air supply pipeline (9), the air inlet end of the air supply pipeline (9) being communicated with the air inlet pipeline (5) and the air outlet end being connected with the air inlet of the air compressor (2). The steps comprise: determining whether the engine body (1) is in a cold start condition based on the acquired coolant temperature data and environmental temperature data of the engine body (1); and controlling the switching assembly (4) to guide high-temperature compressed air generated by the air compressor (2) to the heating pipeline (6) to increase the air inlet temperature if the engine body (1) is in the cold start condition. The cold start system of the methanol engine further comprises: the air inlet pipeline (5) is further internally provided with a second detection assembly for detecting the temperature of the gas and a heating assembly (10); The control of the switching assembly (4) to guide high-temperature compressed air generated by the air compressor (2) to the heating pipeline (6) to increase the air inlet temperature further comprises acquiring the temperature data of the gas in the air inlet pipeline (5); determining whether the temperature data of the gas meet the preset requirement; and controlling the heating assembly (10) to start if the temperature data of the gas do not meet the preset requirement until the temperature data of the gas meet the preset requirement.

5. The cold start system for a methanol engine according to claim 4, wherein ​ ​ 6. The cold start system of a methanol engine according to claim 4, wherein ​ 7. The cold starting system of a methanol engine according to claim 4, wherein ​ 8. The cold starting system of a methanol engine according to claim 4, wherein ​ ​ 9. A control method of a cold start system of a methanol engine according to claim 4, characterized by, ​ ​ ​ 10. The control method of the cold start system of the methanol engine according to claim 9, characterized by, ​ ​ ​ ​

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