CN117028049B - Cold start control method and related device for methanol engine - Google Patents

Abstract

The invention provides a methanol engine cold start control method and related devices. When the ambient temperature is less than a preset value, the methanol engine is started using natural gas fuel, the excess air coefficient of the methanol engine exhaust is obtained, and the excess air coefficient is controlled according to the excess air coefficient. The natural gas fuel supply amount and the methanol fuel supply amount make the combustion mode of the methanol engine equivalent combustion. The invention uses natural gas to assist the cold start of the methanol engine, monitors the combustion situation in the engine cylinder through the excess air coefficient, and reasonably controls the natural gas fuel supply amount and the methanol fuel supply amount, realizes the automatic switching of fuel during the starting stage of the methanol engine, and improves the efficiency of the methanol engine during the starting stage. performance.

Description

A methanol engine cold start control method and related devices

Technical field

The present invention relates to the technical field of methanol engines, and more specifically, to a methanol engine cold start control method and related devices.

Background technique

As a future alternative fuel for engines, methanol fuel has the characteristics of wide sources, simple preparation, and excellent combustion performance. It also has the advantages of reducing soot and nitrogen oxide emissions. Among many alternative fuels, methanol has important research value and Bright application prospects.

However, methanol fuel has high latent heat of vaporization and low saturated vapor pressure, which makes it difficult to form a flammable mixture and lengthens the ignition delay period before the mixture ignites. The latent heat of vaporization of methanol is 3.7 times that of gasoline. When methanol evaporates, it absorbs more heat, causing the temperature in the inlet and cylinder of the methanol engine to drop sharply. When the ambient temperature is low, the evaporation of methanol fuel is insufficient, and the concentration of the combustible mixture cannot reach the ignition lean limit, causing cold start of the methanol engine.

Contents of the invention

In view of this, the present invention provides a methanol engine cold start control method and related devices, which monitor the combustion conditions in the engine cylinder through the excess air coefficient, reasonably control the natural gas fuel supply amount and the methanol fuel supply amount, and realize the fuel supply during the starting stage of the methanol engine. Automatic switching to improve the performance of methanol engines during the startup phase.

In order to achieve the above-mentioned object of the invention, the specific technical solutions provided by the invention are as follows:

In a first aspect, embodiments of the present invention provide a methanol engine cold start control method, including:

When the ambient temperature is lower than the preset value, use natural gas fuel to start the methanol engine;

Obtain the excess air coefficient of the methanol engine exhaust;

According to the excess air coefficient, the natural gas fuel supply amount and the methanol fuel supply amount are controlled so that the combustion mode of the methanol engine is equivalent combustion.

In some embodiments, controlling the natural gas fuel supply amount and the methanol fuel supply amount according to the excess air coefficient so that the combustion mode of the methanol engine is equivalent combustion includes:

When the excess air coefficient is within the preset range, the natural gas fuel supply amount is reduced, and the methanol fuel supply is started, so that the combustion mode of the methanol engine is equivalent combustion.

In some embodiments, after reducing the natural gas fuel supply amount and starting the methanol fuel supply, the method further includes:

Obtain the average excess air coefficient of the methanol engine in a preset number of working cycles;

If the average excess air coefficient is within the preset range, reduce the natural gas fuel supply amount in a stepwise manner, increase the methanol fuel supply amount, and return to perform the acquisition of the average excess air coefficient value of the methanol engine in a preset number of working cycles, Until pure methanol fuel supply is achieved.

In some embodiments, the steps of reducing the natural gas fuel supply and increasing the methanol fuel supply include:

Reduce the supply of natural gas fuel step by step according to a preset proportion;

According to the decrease in the supply of natural gas fuel and the ratio of the calorific value of methanol to the calorific value of natural gas, the amount of increase in methanol fuel is determined so that the work generated by the methanol engine remains unchanged.

In some embodiments, it also includes:

When the ambient temperature is not less than a preset value, methanol fuel is used to start the methanol engine.

In a second aspect, embodiments of the present invention provide a methanol engine cold start control device, including:

Natural gas starting unit, used to start the methanol engine using natural gas fuel when the ambient temperature is lower than the preset value;

An excess air coefficient acquisition unit, used to obtain the excess air coefficient of the methanol engine exhaust;

A fuel supply amount control unit is used to control the natural gas fuel supply amount and the methanol fuel supply amount according to the excess air coefficient, so that the combustion mode of the methanol engine is equivalent combustion.

In some embodiments, the fuel supply control unit is specifically configured to reduce the natural gas fuel supply and start the methanol fuel supply when the excess air coefficient is within a preset range, so that the combustion mode of the methanol engine is Equivalent burning.

In some embodiments, the fuel supply control unit is also configured to obtain the average excess air coefficient of the methanol engine in a preset number of working cycles after reducing the natural gas fuel supply and starting the methanol fuel supply. ; If the average excess air coefficient is within the preset range, reduce the natural gas fuel supply in a stepwise manner, increase the methanol fuel supply, and return to the execution of obtaining the average excess air coefficient of the methanol engine in a preset number of working cycles. , until pure methanol fuel supply is achieved.

In some embodiments, if the average excess air coefficient is within a preset range, the fuel supply control unit is specifically configured to reduce the natural gas fuel supply in a stepwise manner according to a preset proportion; according to the reduction amount of the natural gas fuel supply and the ratio of the calorific value of methanol to the calorific value of natural gas to determine the amount of improvement in methanol fuel so that the work generated by the methanol engine remains unchanged.

In some embodiments, it also includes:

A methanol starting unit is used to start the methanol engine using methanol fuel when the ambient temperature is not less than a preset value.

In a third aspect, embodiments of the present invention provide an electronic control unit, which includes a processor and a memory;

The memory is used to store program code and transmit the program code to the processor;

The processor is configured to execute a methanol engine cold start control method as described in any implementation manner in the first aspect according to instructions in the program code.

In a fourth aspect, embodiments of the present invention provide a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, any one of the implementations in the first aspect is implemented. A methanol engine cold start control method described in this way.

Compared with the prior art, the beneficial effects of the present invention are as follows:

The invention discloses a methanol engine cold start control method and related devices. When the ambient temperature is less than a preset value, natural gas fuel is used to start the methanol engine, thereby improving the starting performance of the methanol engine in low-temperature environments. Obtain the excess air coefficient of the methanol engine exhaust, monitor the combustion situation in the engine cylinder through the excess air coefficient, reasonably control the natural gas fuel supply volume and the methanol fuel supply volume, realize the automatic switching of fuel during the starting stage of the methanol engine, and improve the efficiency of the methanol engine during the starting stage. performance.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the provided drawings without exerting creative efforts.

Figure 1 is a schematic flow chart of a methanol engine cold start control method disclosed in an embodiment of the present invention;

Figure 2 is a partial method flow diagram of a methanol engine cold start control method disclosed in an embodiment of the present invention;

Figure 3 is a partial method flow diagram of a methanol engine cold start control method disclosed in an embodiment of the present invention;

Figure 4 is a partial method flow diagram of a methanol engine cold start control method disclosed in an embodiment of the present invention;

Figure 5 is a schematic structural diagram of a methanol engine cold start control device disclosed in an embodiment of the present invention;

Figure 6 is a schematic structural diagram of an electronic control unit disclosed in an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

The inventor found through research that when a methanol engine is started in a low-temperature environment, only a small amount of methanol evaporates, and the concentration of the combustible mixture cannot reach the ignition lean limit, so the mixture cannot be ignited when the spark plug ignites. If no auxiliary measures are taken, no matter how much methanol fuel is injected in the first cycle of the methanol engine, the methanol engine will not be able to start smoothly. At present, technical solutions such as gasoline-assisted starting, diesel compression ignition ignition, and fuel heater (water boiler) heating-assisted starting are generally used. However, there is a certain amount of pollution in the combustion of gasoline and diesel, and the fuel heater's heating-assisted start-up efficiency is low. As a clean energy source, natural gas has the advantages of environmental protection, economy and high efficiency. Using natural gas to assist methanol cold start has the characteristics of fast start, stability and reliability. In order to improve the low-temperature starting performance of methanol engines, the present invention provides a methanol engine cold start control method. and related devices, using natural gas fuel to assist methanol engine cold start.

The invention provides a methanol engine cold start control method, which is applied to an electronic control unit (ECU) in a vehicle, and the vehicle is a vehicle using a methanol engine. The methanol engine is equipped with natural gas fuel, methanol fuel supply and injection devices at the same time.

Please refer to Figure 1. This embodiment discloses a methanol engine cold start control method, which specifically includes the following steps:

S101: When the ambient temperature is lower than the preset value, use natural gas fuel to start the methanol engine;

The ambient temperature can be detected by the atmospheric environment sensor.

Furthermore, when the sensor used to detect the ambient temperature is illuminated by sunlight, the ambient temperature detected may be greater than the actual ambient temperature. In order to make the ambient temperature more accurate, the minimum temperature value among the ambient temperature, methanol engine intake air temperature, engine oil temperature and engine coolant temperature detected by the sensor can also be used as the above-mentioned ambient temperature.

The preset value can be 16°C. This temperature is related to the physical and chemical properties of methanol fuel. According to relevant research, when the ambient temperature is less than 16°C, methanol fuel does not evaporate, so it is impossible to form a sufficiently concentrated combustible mixture and ignition and combustion cannot be achieved.

Using natural gas fuel to start the methanol engine means controlling the natural gas fuel injection device to inject natural gas fuel to assist in starting the methanol engine, and the methanol fuel injection device does not inject. Natural gas fuel can use a single-point injection scheme in the intake pipe.

When the ambient temperature is not less than the preset value, methanol fuel is used to start the methanol engine, that is, the methanol fuel injection device is controlled to inject methanol fuel to start the methanol engine, and the natural gas fuel injection device does not inject, and subsequent fuel switching is not involved. Methanol fuel can use an intake manifold multi-point injection scheme.

S102: Obtain the excess air coefficient of methanol engine exhaust;

Specifically, a front oxygen sensor is used to obtain the excess air coefficient λ of the methanol engine exhaust, and the front oxygen sensor is installed on the engine exhaust pipe.

The excess air coefficient λ represents the ratio of the actual amount of air supplied for fuel combustion to the theoretical air amount. It is a parameter that reflects the mixing ratio of fuel and air. In other words, it detects the oxygen content in the exhaust gas generated after the combustion of the cylinder mixture. The oxygen content is too high. It means the mixture is too thin; if the oxygen content is too low, it means the mixture is too rich. The front oxygen sensor transmits different electrical signals to the electronic control unit according to different oxygen levels.

S103: According to the excess air coefficient, control the natural gas fuel supply amount and the methanol fuel supply amount so that the combustion mode of the methanol engine is equivalent combustion.

Since the excess air coefficient λ represents the combustion situation in the engine cylinder, the natural gas fuel supply amount and the methanol fuel supply amount are controlled according to the excess air coefficient λ. The excess air coefficient λ is within the preset range. For example, if the excess air coefficient λ is around 1, the methanol engine's The combustion mode is equivalent combustion, which can reduce the natural gas combustion supply and start the methanol fuel supply until pure methanol fuel supply is achieved.

Specifically, the natural gas fuel supply amount and the methanol fuel supply amount must satisfy the combustion mode of the methanol engine which is equivalent combustion. Equivalent combustion means that the stoichiometric ratio of fuel and oxygen is 1. The fuel and oxygen are just completely burned. It also means that the combustion efficiency is higher, the temperature of the combustion chamber is higher, and the production rate of nitrogen oxides in the air will be greatly increased without excess air. reduce.

Therefore, by reasonably controlling the supply amount of natural gas fuel and the supply amount of methanol fuel according to the excess air coefficient, the combustion mode of the methanol engine is equivalent combustion, which improves the combustion efficiency of the fuel in the methanol engine, thereby improving the performance of the methanol engine.

It can be seen that the methanol engine cold start control method disclosed in this embodiment uses natural gas fuel to start the methanol engine when the ambient temperature is less than the preset value, thereby improving the starting performance of the methanol engine in low temperature environments. Obtain the excess air coefficient of the methanol engine exhaust, monitor the combustion situation in the engine cylinder through the excess air coefficient, reasonably control the natural gas fuel supply volume and the methanol fuel supply volume, realize the automatic switching of fuel during the starting stage of the methanol engine, and improve the efficiency of the methanol engine during the starting stage. performance.

In some embodiments, in S103 of the above embodiment, the natural gas fuel supply amount and the methanol fuel supply amount are controlled according to the excess air coefficient, so that the combustion mode of the methanol engine is equivalent combustion. An optional implementation method is shown in Figure 2 , specifically including the following steps:

S201: Determine whether the excess air coefficient is within the preset range;

When the excess air coefficient is within the preset range, execute S202: reduce the natural gas fuel supply and start the methanol fuel supply so that the combustion mode of the methanol engine is equivalent combustion;

When the excess air coefficient is not within the preset range, perform S203: control the natural gas fuel supply amount according to the equivalent combustion mode, and do not start the methanol fuel supply.

It should be noted that the excess air coefficient here is obtained in the first working cycle of the methanol engine, in which the four processes of air intake, compression, power generation and exhaust are completed as one working cycle. The faster the engine speed, the longer the working cycle time. The shorter.

If the excess air coefficient is within the preset range, for example, the excess air coefficient λ is around 1, it is determined that the combustion efficiency in the engine cylinder is high, and the natural gas fuel supply can be gradually reduced and the methanol fuel supply can be started. If the excess air coefficient is not within the preset range, it is determined that the combustion in the engine cylinder is poor. At this time, the methanol fuel supply is not started, and the natural gas fuel supply amount is controlled according to the equivalent combustion mode.

After reducing the natural gas fuel supply and starting the methanol fuel supply, in order to reasonably control the natural gas fuel supply and the methanol fuel supply, so that the combustion mode of the methanol engine is equivalent combustion and improve the combustion efficiency in the engine cylinder, it is also necessary to obtain the excess air coefficient , controlling the natural gas fuel supply amount and the methanol fuel supply amount according to the excess air coefficient. Two optional implementation methods are provided below:

Method 1, as shown in Figure 3, includes the following steps:

S301: For each working cycle, determine whether pure methanol fuel is supplied;

If the fuel supply is not pure methanol, S302: Get the excess air coefficient;

S303: If the excess air coefficient is not within the preset range, the methanol fuel supply will not be adjusted, and the natural gas fuel supply will be adjusted according to the equivalent combustion method;

S304: If the excess air coefficient is within the preset range, reduce the natural gas fuel supply amount in a stepwise manner, increase the methanol fuel supply amount, and return to S301 until pure methanol fuel supply is achieved.

Method 2, as shown in Figure 4, includes the following steps:

S401: Determine whether it is pure methanol fuel supply;

If it is not pure methanol fuel supply, S402: Obtain the average excess air coefficient of the methanol engine in a preset number of working cycles;

S403: If the average excess air coefficient is not within the preset range, the methanol fuel supply will not be adjusted, and the natural gas fuel supply will be adjusted according to the equivalent combustion method;

S404: If the average excess air coefficient is within the preset range, reduce the natural gas fuel supply amount in a stepwise manner, increase the methanol fuel supply amount, and return to S401 until pure methanol fuel supply is achieved.

The preset number can be set according to the actual application scenario, for example, it is set to 3, which is not specifically limited in the present invention.

Among them, the above stepwise reduction of natural gas fuel supply and increase of methanol fuel supply are as follows:

Reduce the supply of natural gas fuel step by step according to a preset proportion;

According to the decrease in the supply of natural gas fuel and the ratio of the calorific value of methanol to the calorific value of natural gas, the amount of increase in methanol fuel is determined so that the work generated by the methanol engine remains unchanged.

For example, if the natural gas fuel supply is reduced in a stepwise manner according to a ratio of 10%, the reduction in natural gas fuel supply is 10% of the natural gas fuel in the previous working cycle. The ratio of the calorific value of methanol to the calorific value of natural gas is 1:2. The natural gas fuel supply is The decrease amount is 10% of the natural gas fuel in the previous working cycle, and the increase amount of methanol fuel is 20% of the natural gas fuel in the previous working cycle, in order to ensure that the work generated by the methanol engine remains unchanged.

Based on the methanol engine cold start control method disclosed in the above embodiment, this embodiment correspondingly discloses a methanol engine cold start control device. Please refer to Figure 5. The device includes:

The natural gas starting unit 501 is used to start the methanol engine using natural gas fuel when the ambient temperature is lower than the preset value;

Excess air coefficient acquisition unit 502, used to obtain the excess air coefficient of the methanol engine exhaust;

The fuel supply amount control unit 503 is used to control the natural gas fuel supply amount and the methanol fuel supply amount according to the excess air coefficient, so that the combustion mode of the methanol engine is equivalent combustion.

In some embodiments, the fuel supply control unit 503 is specifically configured to reduce the natural gas fuel supply when the excess air coefficient is within a preset range, and start the methanol fuel supply to change the combustion mode of the methanol engine. For equivalent burning.

In some embodiments, the fuel supply control unit 503 is also configured to obtain the excess air coefficient of the methanol engine in a preset number of working cycles after reducing the natural gas fuel supply and starting the methanol fuel supply. mean value; if the mean value of the excess air coefficient is within the preset range, reduce the natural gas fuel supply amount in a stepwise manner, increase the methanol fuel supply amount, and return to the execution of obtaining the excess air coefficient of the methanol engine in a preset number of working cycles. mean until pure methanol fuel supply is achieved.

In some embodiments, if the average excess air coefficient is within a preset range, the fuel supply control unit 503 is specifically configured to reduce the natural gas fuel supply in a stepwise manner according to a preset proportion; according to the reduction in the natural gas fuel supply The amount and the ratio of the calorific value of methanol to the calorific value of natural gas are determined to increase the amount of methanol fuel so that the work generated by the methanol engine remains unchanged.

In some embodiments, it also includes:

A methanol starting unit is used to start the methanol engine using methanol fuel when the ambient temperature is not less than a preset value.

This embodiment discloses a methanol engine cold start control device that uses natural gas fuel to start the methanol engine when the ambient temperature is less than a preset value, thereby improving the starting performance of the methanol engine in low-temperature environments. Obtain the excess air coefficient of the methanol engine exhaust, monitor the combustion situation in the engine cylinder through the excess air coefficient, reasonably control the natural gas fuel supply volume and the methanol fuel supply volume, realize the automatic switching of fuel during the starting stage of the methanol engine, and improve the efficiency of the methanol engine during the starting stage. performance.

An embodiment of the present invention also provides an electronic control unit. For example, please refer to FIG. 6 . The electronic control unit includes a processor 601 and a memory 602;

The memory 602 is used to store program codes and transmit the program codes to the processor 601;

The processor 601 is configured to execute a methanol engine cold start control method as described in any implementation manner in the above embodiments according to instructions in the program code.

Embodiments of the present invention also provide a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, it implements the implementation described in any of the above embodiments. A methanol engine cold start control method.

Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on its differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple. For relevant details, please refer to the description in the method section.

It should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations There is no such actual relationship or sequence between them. Furthermore, the terms "comprises," "comprises," or any other variations thereof are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also those not expressly listed other elements, or elements inherent to the process, method, article or equipment. Without further limitation, an element defined by the statement "comprises a..." does not exclude the presence of additional identical elements in a process, method, article, or apparatus that includes the stated element.

The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly in hardware, in software modules executed by a processor, or in a combination of both. Software modules may be located in random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or anywhere in the field of technology. any other known form of storage media.

The above-mentioned embodiments can be combined arbitrarily. The above description of the disclosed embodiments and the features recorded in each embodiment in this specification can be replaced or combined with each other, so that those skilled in the art can implement or use the present application.

The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be practiced in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. A method for controlling cold start of a methanol engine, comprising:

under the condition that the ambient temperature is less than a preset value, starting the methanol engine by adopting natural gas fuel;

acquiring an excess air ratio of the exhaust of the methanol engine;

according to the excess air coefficient, controlling the natural gas fuel supply amount and the methanol fuel supply amount to enable the combustion mode of the methanol engine to be equivalent combustion;

and controlling the natural gas fuel supply amount and the methanol fuel supply amount according to the excess air coefficient to enable the combustion mode of the methanol engine to be equivalent combustion, wherein the method comprises the following steps of:

judging whether the excess air coefficient is within a preset range;

when the excess air coefficient is in a preset range, reducing the natural gas fuel supply amount, and starting the methanol fuel supply to enable the combustion mode of the methanol engine to be equivalent combustion;

and when the excess air coefficient is not in the preset range, controlling the natural gas fuel supply amount according to the equivalent combustion mode, and not starting the methanol fuel supply.

2. The methanol engine cold start control method as set forth in claim 1, further comprising, after the reducing the natural gas fuel supply amount and starting the methanol fuel supply:

acquiring an average value of excess air coefficients of the methanol engine in a preset number of working cycles;

and if the average value of the excess air coefficient is in the preset range, reducing the natural gas fuel supply amount stepwise, improving the methanol fuel supply amount, and returning to execute the step of obtaining the average value of the excess air coefficient of the methanol engine in the preset number of working cycles until the pure methanol fuel supply is realized.

3. The method for controlling cold start of a methanol engine according to claim 2, wherein the stepwise decreasing of the natural gas fuel supply amount and increasing of the methanol fuel supply amount comprises:

stepwise reducing the natural gas fuel supply according to a preset proportion;

and determining the increasing amount of the methanol fuel according to the decreasing amount of the natural gas fuel supply and the ratio of the methanol heat value to the natural gas heat value, so that the work generated by the methanol engine is unchanged.

4. The methanol engine cold start control method as set forth in claim 1, further comprising:

and under the condition that the ambient temperature is not less than a preset value, starting the methanol engine by adopting methanol fuel.

5. A cold start control device for a methanol engine, comprising:

the natural gas starting unit is used for starting the methanol engine by adopting natural gas fuel under the condition that the ambient temperature is smaller than a preset value;

an excess air ratio acquisition unit for acquiring an excess air ratio of the methanol engine exhaust gas;

a fuel supply amount control unit for controlling the natural gas fuel supply amount and the methanol fuel supply amount according to the excess air ratio so that the combustion mode of the methanol engine is equivalent combustion;

the fuel supply amount control unit is specifically configured to determine whether the excess air ratio is within a preset range; when the excess air coefficient is in a preset range, reducing the natural gas fuel supply amount, and starting the methanol fuel supply to enable the combustion mode of the methanol engine to be equivalent combustion; and when the excess air coefficient is not in the preset range, controlling the natural gas fuel supply amount according to the equivalent combustion mode, and not starting the methanol fuel supply.

6. The methanol engine cold start control apparatus as set forth in claim 5, wherein the fuel supply amount control unit is further configured to obtain an average value of excess air ratio of the methanol engine over a preset number of operating cycles after the reducing of the natural gas fuel supply amount and starting of the methanol fuel supply; and if the average value of the excess air coefficient is in the preset range, reducing the natural gas fuel supply amount stepwise, improving the methanol fuel supply amount, and returning to execute the step of obtaining the average value of the excess air coefficient of the methanol engine in the preset number of working cycles until the pure methanol fuel supply is realized.

7. An electronic control unit, characterized in that the electronic control unit comprises a processor and a memory;

the memory is used for storing program codes and transmitting the program codes to the processor;

the processor is configured to execute a cold start control method for a methanol engine according to any one of claims 1 to 4 according to instructions in the program code.

8. A computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, which when executed by a processor, implements a methanol engine cold start control method as set forth in any one of claims 1-4.