Methanol injection method and device of methanol engine and calibration method

Abstract

The invention discloses a methanol injection method of a methanol engine, and relates to the methanol engine, methanol fuel injected from a methanol nozzle is conveyed in a spiral conveying manner, so that atomized methanol fuel and methanol liquid drops are separated, the atomized methanol fuel is conveyed into a combustion chamber, and the combustion chamber is communicated with a combustion chamber. And the methanol liquid drops are conveyed to the spraying side of the methanol nozzle to be heated and evaporated. The invention further discloses a methanol injection device of the methanol engine and a calibration method. According to the invention, the energy of air is fully utilized to evaporate methanol droplets, so that the evaporation effect of methanol particles is ensured, and the atomization efficiency of suspension droplet particles is improved.

Description

Technical Field

[0001] The present invention relates to a methanol engine, and more particularly to a methanol injection method, a device and a calibration method of a methanol engine. Background Art

[0002] The current methanol engines generally use M100 methanol (i.e. pure methanol) as the main fuel, and burn through intake manifold injection and spark plug ignition. However, when the ambient temperature drops to 16°C or below, it is difficult to achieve combustion by methanol injection alone, so an auxiliary starting method is needed. The main reasons for this problem include: first, methanol has a high atomization latent heat, which is more than three times that of gasoline, which causes methanol to absorb a large amount of heat under low temperature conditions and it is difficult to form a sufficient combustible mixture; second, the saturated vapor pressure of methanol is low, much lower than that of gasoline, which limits the evaporation of methanol and reduces the content of methanol vapor in the cylinder; finally, the flash point and ignition temperature of methanol are high. Under low temperature conditions, due to the endothermic effect during the evaporation process, the ambient temperature in the cylinder may drop below the flash point temperature of methanol.

[0003] To address the above issues, the current solutions in the industry include:

[0004] 1) When the temperature is below 16°C, use gasoline injection to assist in starting, and then inject methanol after the engine is warmed up;

[0005] 2) Using air-assisted nozzle technology, the particle size of the spray droplets is reduced from 60-150 μm to 7-9 μm, so that the methanol engine can still achieve cold start at 5°C;

[0006] 3) With direct injection, the cold start temperature is as low as 5°C;

[0007] 4) Heat the coolant to above 30°C, so that it can be successfully started at an ambient temperature of -30°C;

[0008] 5) Intake air heating, which can extend the cold start temperature to -12℃.

[0009] However, if Figure 1 As shown, the conventional injector forms an angle of 30 to 60 degrees with the airflow direction, and the methanol droplets are injected at an inclined angle, and the droplets cannot be evenly distributed in the pipeline. The injected large methanol droplets will be concentrated at the bottom of the pipeline, and the wet wall area is small, making it difficult to evaporate. Therefore, although the above method can start the methanol engine normally, it still cannot solve the problem that large methanol droplets are concentrated at the bottom of the pipeline and difficult to evaporate. Summary of the invention

[0010] The technical problem to be solved by the present invention is to provide a methanol injection method, device and calibration method for a methanol engine in view of the deficiencies in the prior art.

[0011] The methanol injection method of a methanol engine described in the present invention transmits the methanol fuel sprayed from the methanol nozzle in a spiral transmission manner to separate the atomized methanol fuel and methanol droplets. The atomized methanol fuel is transported to a combustion chamber, and the methanol droplets are transported to the injection side of the methanol nozzle for heating and evaporation.

[0012] Preferably, a rotating flow field is created in the intake pipe in the opposite direction of the injection direction of the methanol nozzle, and the methanol fuel is blown toward the methanol fuel injected from the methanol nozzle by the rotating flow field to perform spiral transmission of the methanol fuel.

[0013] Preferably, a heating zone is constructed in the air intake pipe on the injection direction side of the methanol nozzle, and the heating zone protrudes from the inner wall of the air intake pipe to prevent the accumulation of the methanol droplets.

[0014] Preferably, the temperature of the heating zone is 70°C-100°C.

[0015] Preferably, the injection direction of the methanol nozzle is consistent with the axial direction of the intake pipe.

[0016] A methanol injection device for implementing the methanol injection method, characterized by comprising:

[0017] A fan, which is installed on the opposite side of the methanol nozzle injection direction and is used to generate a rotating flow field;

[0018] Methanol nozzle, used for injecting methanol fuel;

[0019] The heating unit is installed in the air intake pipe on the injection direction side of the methanol nozzle and is used to heat and evaporate the methanol droplets.

[0020] Preferably, the heating unit comprises a plurality of heaters, the plurality of heaters are evenly arranged around the inner wall of the air intake pipe, and the heaters protrude from the inner wall of the air intake pipe.

[0021] Preferably, all the heaters are fixedly mounted on a heat-conducting sleeve, and the heat-conducting sleeve is fixedly mounted on the inner wall of the air inlet pipe to form a blocking surface for the methanol droplets.

[0022] Preferably, the heat-conducting sleeve is a copper sleeve, and the thickness of one side of the heat-conducting sleeve close to the nozzle is smaller than the thickness of the other side thereof.

[0023] A calibration method for calibrating the fan speed and heater power in the methanol injection device comprises the following steps:

[0024] The first step is to place the methanol engine equipped with the methanol injection device on a test bench;

[0025] Step 2: setting the intake air flow rate and intake air temperature at the intake port of the intake pipe to simulate different operating conditions of the methanol engine;

[0026] The third step is to operate the methanol engine at the intake flow rate and intake temperature set in the second step, and control the methanol nozzle to spray methanol fuel according to the set injection amount, while monitoring the number of droplets in the intake pipe on the side of the heating unit away from the methanol nozzle; adjust the fan speed and the heater power, and take the fan speed and the heater power when the number of droplets is the least and the temperature of the heat transfer sleeve does not exceed the set safety limit as the calibration value.

[0027] Beneficial Effects

[0028] The advantages of the present invention are:

[0029] 1. By disturbing the horizontally flowing airflow to create a rotating flow field, the airflow is made to flow in a spiral in the intake pipe. Under the action of the rotating flow field, the droplets ejected from the methanol nozzle can not only accelerate evaporation, but also the methanol droplets have a large inertia due to the centrifugal force and collide with the pipe wall. The atomized methanol fuel has a small inertia and flows forward in the rotating flow field, thus achieving the separation of the droplets in the methanol fuel and the atomized methanol fuel. In addition, the energy of the air is fully utilized to evaporate the methanol droplets, ensuring the evaporation effect of the methanol particles.

[0030] 2. Through the design of the heating unit, the methanol droplets are heated and evaporated, and the problem that the methanol droplets cannot be completely evaporated and atomized while passing through the heating zone along the wall of the intake pipe is avoided, which greatly enhances the evaporation capacity and efficiency of the methanol droplets. In addition, due to the disturbance effect of the rotating flow field, the original laminar boundary layer of the pipe wall of the intake pipe is destroyed, and the convection heat transfer coefficient between the airflow and the heating unit is enhanced. This process not only promotes the rapid evaporation of the methanol droplets, but also improves the atomization efficiency of the suspended droplet particles by heating the intake airflow.

[0031] 3. The spray direction of the methanol nozzle is completely consistent with the airflow direction and is located in the center of the pipeline. This design allows the methanol to be sprayed evenly in all directions, thereby effectively achieving uniform distribution of the spray droplets in the pipeline and making full use of the energy of the intake air to promote the evaporation of the methanol droplets. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the installation structure of a traditional methanol injector;

[0033] Figure 2a An axial view of the conventional methanol fuel injection method in the intake pipe;

[0034] Figure 2b An axial view of the methanol fuel injection in the intake pipe of the present invention;

[0035] Figure 3 It is a schematic diagram of the installation structure of the heater and the heat-conducting sleeve of the present invention;

[0036] Figure 4 This is a schematic diagram of the installation structure of the methanol injection device of the present invention;

[0037] Figure 5 A schematic diagram of the installation structure of a methanol injection device used in the calibration method of the present invention;

[0038] Figure 6 This is a calibration test record table for the fan speed and heater temperature of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0040] A methanol injection method for a methanol engine of the present invention transmits the methanol fuel sprayed from the methanol nozzle in a spiral transmission manner, and the spiral transmission manner can make the sprayed methanol fuel have centrifugal force, and its heavier droplets will hit the inner wall of the intake pipe, while the smaller particles and atomized methanol fuel will be suspended in the pipe, move forward with the fluid, and continue to evaporate in the subsequent flow process, thereby achieving the separation of the atomized methanol fuel and the methanol droplets. In addition, another advantage of the spiral transmission is that the methanol droplets can be more evenly distributed on the inner wall of the intake pipe. Figure 2a and Figure 2b As shown, Figure 2a This is an axial view of the traditional methanol fuel injection method in the intake pipe. It can be seen that there is a large amount of air and droplet injection area that do not intersect, resulting in a waste of air energy. Moreover, if the nozzle is simply increased, the droplet particle beams on both sides are too close to the pipe wall, causing a large amount of dense liquid to hit the wall, resulting in poor evaporation effect. Figure 2b This is an axial view of the methanol fuel injection in the intake pipe of the present invention. It can be seen from the figure that the methanol droplets are evenly distributed and fully contact the air, fully utilizing the energy of the air to evaporate the methanol droplets, thereby ensuring the evaporation effect of the methanol particles.

[0041] Specifically, in this embodiment, a rotating flow field is created in the intake pipe in the opposite direction of the methanol nozzle injection direction, and the methanol fuel is blown toward the methanol fuel injected from the methanol nozzle by the rotating flow field to perform spiral transmission of the methanol fuel, thereby achieving spiral transmission of the injected methanol fuel. In this way, there is no need to make too many improvements to the methanol nozzle, which greatly saves costs.

[0042] The atomized methanol fuel is transported to the combustion chamber, and the methanol droplets are transported to the injection side of the methanol nozzle for heating and evaporation, so that the methanol droplets are quickly evaporated and atomized, so that enough methanol fuel can accumulate in the combustion chamber of the methanol engine within an extremely long time, which is very beneficial to the cold start of the methanol engine.

[0043] Specifically, a heating zone is constructed in the intake pipe on the injection direction side of the methanol nozzle, and the heating zone protrudes from the inner wall of the intake pipe to block the accumulation of methanol droplets. Such a design not only realizes the heating and evaporation of methanol droplets, but also avoids the problem that the droplets pass through the heating zone along the wall of the intake pipe and cannot be completely evaporated and atomized, greatly enhancing the evaporation capacity and efficiency of methanol droplets.

[0044] In this embodiment, the temperature of the heating zone is 70° C.-100° C., which is conducive to the evaporation of methanol droplets.

[0045] In addition, the injection direction of the methanol nozzle is consistent with the axial direction of the intake pipe. The direction of the traditional methanol injector is at an angle of 30°-60° with the airflow direction, and the methanol is injected obliquely, which makes it difficult to achieve uniform distribution of the injected droplets in the pipeline. The methanol nozzle of the present invention is combined with a 90° elbow, so that the injection direction of the methanol nozzle is consistent with the airflow direction, and is located in the center of the intake pipe, spraying methanol fuel all around, and cooperating with a rotating flow field, thereby achieving uniform distribution of methanol droplets in the intake pipe, and fully utilizing the energy of the intake air to achieve evaporation of methanol droplets. The combination of maximum utilization of the intake energy and heating evaporation can achieve rapid evaporation and atomization of methanol droplets.

[0046] A methanol injection device for implementing the above-mentioned methanol injection method, such as Figure 3 As shown, it includes a fan 2, a methanol nozzle 3 and a heating unit.

[0047] The fan 2 is installed on the opposite side of the injection direction of the methanol nozzle 3 to generate a rotating flow field. The methanol nozzle 3 is used to inject methanol fuel, and is combined with a 90° elbow so that the injection direction of the methanol nozzle is consistent with the airflow direction and is located at the center of the intake pipe. The heating unit is installed in the intake pipe 1 on the injection direction side of the methanol nozzle 3 to heat and evaporate the methanol droplets.

[0048] Specifically, Figure 4As shown, the heating unit includes a plurality of heaters 4, and the plurality of heaters 4 are evenly arranged around the inner wall of the intake pipe 1, and the heaters 4 protrude from the inner wall of the intake pipe 1. All heaters 4 are fixedly mounted on a heat-conducting sleeve 5, and the heat-conducting sleeve 5 is heated by the heaters 4. The heat-conducting sleeve 5 is fixedly mounted on the inner wall of the intake pipe 1 to form a blocking surface for the methanol droplets. Through the blocking of the heat-conducting sleeve 5 and its protruding design with the heater 4, the blocked methanol droplets and the methanol droplets that hit it can be heated, so as to be quickly evaporated.

[0049] Preferably, the heat-conducting sleeve 5 is a copper sleeve, and the thickness of the side of the heat-conducting sleeve 5 close to the nozzle is less than the thickness of the other side. That is, the inner ring of the heat-conducting sleeve 5 is a high-side and low-side inclined structure, which can make its area larger and better capture methanol droplets.

[0050] A calibration method for calibrating the fan speed and heater power in the above-mentioned methanol injection device, such as Figure 5 As shown, the method comprises the following steps:

[0051] The first step is to place the methanol engine equipped with a methanol injection device on the test bench, and add a flow meter 6 at the entrance of the intake pipe 1 to measure the flow and temperature of the gas. The function of the flow meter is to control the test conditions. A thermometer is arranged on the copper sleeve to monitor the temperature of the copper sleeve to prevent the temperature of the copper sleeve from exceeding the safe temperature boundary; a liquid particle measurement device 7 is set at the outlet of the intake pipe 1, and its results are used to evaluate the atomization and evaporation effect of methanol.

[0052] The second step is to set the intake flow rate and intake temperature at the intake port of intake pipe 1 to simulate different operating conditions of the methanol engine. Taking the air flow rate at the inlet of the intake pipe as 100kg / h and 150kg / h, and the temperature as 0℃ and 5℃, the flow rate and temperature of each operating condition are determined to be 100kg / h@0℃, 150kg / h@0℃, 100kg / h@5℃, and 150kg / h@5℃. The flow rates and temperatures of these operating conditions are tested one by one in the third step.

[0053] The third step is to operate the methanol engine at the intake flow rate and intake temperature set in the second step, and control the methanol nozzle 3 to spray methanol fuel according to the set injection amount, while monitoring the number of droplets in the intake pipe 1 on the side of the heating unit away from the methanol nozzle 3. Adjust the speed of the fan 2 and the power of the heater 4, and take the fan speed and heater power at the moment when the number of droplets is the least and the temperature of the heat-conducting sleeve 5 does not exceed the set safety limit as the calibration value.

[0054] The final test record is as follows: Figure 6As shown, the fan speed and heater power under different intake boundaries and methanol injection amounts can be finally obtained, thereby ensuring that the methanol engine can achieve optimal atomization evaporation under any cold start conditions and guaranteeing the cold start performance of the methanol engine.

[0055] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A methanol injection method for a methanol engine, characterized in that: The methanol fuel sprayed out from the methanol nozzle is conveyed in a spiral transmission manner to separate the atomized methanol fuel and the methanol droplets. The atomized methanol fuel is transported to the combustion chamber, and the methanol droplets are transported to the injection side of the methanol nozzle for heating and evaporation.

2. The methanol injection method for a methanol engine according to claim 1, characterized in that: A rotating flow field is created in the intake pipe in the opposite direction of the methanol nozzle injection direction, and the methanol fuel injected from the methanol nozzle is blown toward the methanol fuel by the rotating flow field to perform spiral transmission of the methanol fuel.

3. The methanol injection method for a methanol engine according to claim 1, characterized in that: A heating zone is constructed in the air intake pipe on the injection direction side of the methanol nozzle, and the heating zone protrudes from the inner wall of the air intake pipe to prevent the accumulation of the methanol droplets.

4. The methanol injection method for a methanol engine according to claim 3, characterized in that: The temperature of the heating zone is 70°C-100°C.

5. A methanol injection method for a methanol engine according to any one of claims 1 to 4, characterized in that: The injection direction of the methanol nozzle is consistent with the axial direction of the intake pipe.

6. A methanol injection device for implementing the methanol injection method according to any one of claims 1 to 5, characterized in that: include: A fan (2) is installed on the opposite side of the injection direction of the methanol nozzle (3) to generate a rotating flow field; A methanol nozzle (3) for injecting methanol fuel; A heating unit is installed in the air intake pipe (1) on the injection direction side of the methanol nozzle (3) and is used to heat and evaporate methanol droplets.

7. A methanol injection device according to claim 6, characterized in that: The heating unit comprises a plurality of heaters (4), the plurality of heaters (4) being evenly arranged around the inner wall of the air intake pipe (1), and the heaters (4) protruding from the inner wall of the air intake pipe (1).

8. A methanol injection device according to claim 7, characterized in that: All the heaters (4) are fixedly mounted on a heat-conducting sleeve (5), and the heat-conducting sleeve (5) is fixedly mounted on the inner wall of the air intake pipe (1) to form a blocking surface for the methanol droplets.

9. A methanol injection device according to claim 8, characterized in that: The heat-conducting sleeve (5) is a copper sleeve, and the thickness of one side of the heat-conducting sleeve (5) close to the nozzle is smaller than the thickness of the other side thereof.

10. A calibration method for calibrating the fan speed and heater power in the methanol injection device according to any one of claims 6 to 9, characterized in that: The following steps are involved: The first step is to place the methanol engine equipped with the methanol injection device on a test bench; Step 2: setting the intake air flow rate and intake air temperature at the intake port of the intake pipe (1) to simulate different operating conditions of the methanol engine; The third step is to operate the methanol engine at the intake flow rate and intake temperature set in the second step, and control the methanol nozzle (3) to spray methanol fuel according to the set spray amount, while monitoring the number of droplets in the intake pipe (1) on the side of the heating unit away from the methanol nozzle (3); adjust the speed of the fan (2) and the power of the heater (4), and take the fan speed and heater power at the moment when the number of droplets is the least and the temperature of the heat-conducting sleeve (5) does not exceed the set safety limit as the calibration value.

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