A method for improving the performance of a methanol engine by controlling the alcohol-air mixture

Abstract

The application discloses an alcohol gas mixing control method for improving the performance of a methanol engine, and comprises the following steps: a single cylinder assembly is applied to the method, the single cylinder assembly comprises at least two air channels, and a methanol injector is fixed in each air channel; the control method comprises the following steps: obtaining a rotating state of the engine during operation; judging whether the rotating speed of the engine during operation exceeds a preset value; adjusting the injection state of the methanol injector according to the rotating state of the engine during operation through a control module, and controlling the combustion mode in the cylinder according to the adjusted injection state of the methanol injector. According to the application, the flow mode of the combustible mixed gas flow is reasonably organized in combination with different operation conditions, and more efficient combustion is realized.

Description

Technical Field

[0001] This invention relates to the technical field of road traffic emissions, and in particular to a method for controlling methanol-gas mixture to improve the performance of methanol engines. Background Technology

[0002] During the operation of an internal combustion engine, airflow patterns have a significant impact on combustion efficiency. The quality of the intake airflow organization directly affects the engine's in-cylinder combustion performance. Coordinating the formation of a 866 mixture within the operating range of a methanol engine is a crucial prerequisite for reliable and complete combustion, achieving high efficiency and low harmful emissions. The good operating performance of a methanol engine directly depends on the formation of a stable mixture. The flow characteristics of the methanol engine's intake manifold play a vital role in key parameters such as the amount of air entering the cylinder, gas velocity distribution, swirl ratio, and flow coefficient, directly affecting mixture formation and combustion. Therefore, rationally organizing the airflow in a methanol engine can accelerate alcohol-air mixing, improve combustion, and enhance the engine's power, economy, and emissions.

[0003] Currently, the common intake methods for spark-ignition methanol engines are mainly two types: swirl and tumble, which have different formation mechanisms. Swirls are usually generated through the design of the intake manifold, such as a spiral intake manifold. The structural parameters of the spiral intake manifold play a crucial role in the generation of in-cylinder swirl. Reasonable intake manifold structural parameters can not only ensure the generation of strong swirl during the intake process, but also ensure strong swirl during the compression process and near the top dead center of compression. By matching it with the injection timing, it can ensure that there is an optimal swirl ratio in the cylinder during fuel injection and combustion, promoting fuel-air mixing and improving the utilization rate of in-cylinder air, thereby improving engine power, economy, and emissions. Tumble, on the other hand, is promoted through the design of the straight intake manifold and the shape of the piston crown.

[0004] Swirls persist throughout the combustion process, helping to maintain stable flame propagation, while tumbles break up near top dead center during the compression stroke, generating small-scale turbulence that helps accelerate in-cylinder combustion. Swirls help stabilize combustion at low speeds but may increase pumping losses; tumbles are more effective at high speeds, promoting rapid combustion, but may be less effective at low speeds. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for controlling the alcohol-gas mixture to improve the performance of methanol engines. This method rationally organizes the flow pattern of the combustible mixture under different operating conditions to achieve more efficient combustion. To achieve the above-mentioned objectives and other advantages of the present invention, a method for controlling the alcohol-gas mixture to improve the performance of methanol engines is provided, comprising: A single-cylinder assembly applied to the method, the single-cylinder assembly comprising at least two air passages, each air passage having a methanol injector fixedly connected thereto; The control method includes the following steps: Obtain the engine's rotational state during operation; Determine whether the engine speed exceeds a preset value during operation; The control module adjusts the methanol injector's injection state based on the engine's rotation status, thereby controlling the in-cylinder combustion mode.

[0006] Preferably, the single-cylinder assembly includes a cylinder body, on which two air passages are provided, and a first methanol injector and a second methanol injector are respectively fixedly connected to the two air passages.

[0007] Preferably, the cylinder block has two air passages, specifically one parallel air passage and the other a spiral air passage.

[0008] Preferably, a first methanol injector is fixedly connected to the parallel air passage, and a second methanol injector is fixedly connected to the spiral air passage.

[0009] Preferably, obtaining the engine's rotational state during operation specifically includes obtaining the engine's low-speed operation state and obtaining the engine's overspeed operation state.

[0010] Preferably, the step of adjusting the methanol injector injection state by the control module according to the engine's rotation state during operation specifically involves: When the generator is running at low speed, the control module controls the second methanol injector to work normally and controls the first methanol injector to be in the off state. When the generator is in overspeed operation, the control module controls the first methanol injector to operate normally and controls the second methanol injector to be in the off state.

[0011] Compared with the prior art, the advantages and positive effects of the present invention are: By using a dual-intake, dual-injector alcohol-gas mixing scheme, and monitoring different engine speeds with the ECU to control the operation of different injectors, the combustion mode in the cylinder can be controlled, thereby improving the combustion performance of the methanol engine, increasing engine thermal efficiency, and reducing the risk of knocking. Attached Figure Description

[0012] Figure 1 A schematic diagram of the existing vortex intake stroke of the methanol-gas mixing control method for improving methanol engine performance according to the present invention; Figure 2 A schematic diagram of the existing tumble intake stroke of the methanol-gas mixing control method for improving methanol engine performance according to the present invention; Figure 3 A schematic diagram of the structure of two gas passages in the methanol-gas mixing control method for improving methanol engine performance according to the present invention; Figure 4 This is a schematic flowchart of the methanol-gas mixing control method for improving methanol engine performance according to the present invention. Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] Table 1 compares the advantages and disadvantages of eddies and tumbles.

[0015] Table 1 Comparison of characteristics of eddies and tumble flows characteristic vortex Tumble Combustion stability Stabilizes flame propagation at low speeds, reducing the risk of detonation. Turbulence increases at high speeds, accelerating combustion. Blending effects It promotes large-scale mixing of oil and gas, but micro-scale mixing is weak. The breakup generates high turbulent kinetic energy, resulting in more thorough micro-mixing. Figure 1 The middle section refers to swirl intake, which is typically generated through the design of the intake manifold, such as a spiral intake manifold. The structural parameters of the spiral intake manifold play a crucial role in the generation of in-cylinder swirl. Appropriate manifold structural parameters not only ensure strong swirl during intake but also guarantee strong swirl during compression and near top dead center. Matching this with the injection timing ensures an optimal swirl ratio in the cylinder during combustion, promoting fuel-air mixing and improving in-cylinder air utilization, thereby improving engine power, fuel economy, and emissions.

[0016] like Figure 2 As shown, this is a tumble intake method, where tumble is facilitated by the shape design of the straight intake passage and the piston top.

[0017] This application targets spark-ignition methanol engines, which require a reasonable organization of the combustible mixture flow pattern in combination with different operating conditions to achieve more efficient combustion.

[0018] like Figure 3 As shown, each cylinder in the cylinder head is designed with a parallel intake port and a spiral intake port. The spiral intake port is used to generate an intake vortex. Each cylinder uses two methanol injectors, namely the first methanol injector and the second methanol injector. During engine operation, the first methanol injector and the second methanol injector are controlled to work according to the injection control strategy based on the data collected in real time by the ECU, and fuel is injected into the parallel intake port and the spiral intake port respectively.

[0019] A method for controlling methanol-gas mixture to improve the performance of a methanol engine, comprising: Obtain the engine's rotational state during operation; Determine whether the engine speed exceeds a preset value during operation; The control module adjusts the methanol injector's injection state based on the engine's rotation status, thereby controlling the in-cylinder combustion mode.

[0020] Furthermore, when the engine is running at low speed, i.e., when the actual engine speed is lower than the set value A, the piston movement speed is slow at low speeds, resulting in insufficient tumble breaking and insufficient turbulent kinetic energy, which affects the combustion stability under low load. In order to achieve stable flame propagation in the cylinder and reduce the risk of knocking, a vortex intake method is adopted at this time to control the second methanol injector to work, while the first methanol injector does not work.

[0021] When the engine speed exceeds A, the high tumble intensity is fully utilized to accelerate flame propagation and achieve rapid combustion of the in-cylinder airflow, thus realizing rapid combustion of the airflow in the cylinder. At this time, the first methanol injector is activated while the second methanol injector is deactivated. The premixed combustible mixture enters the cylinder through a parallel air passage, improving the engine's thermal efficiency.

[0022] Furthermore, such as Figure 4 As shown, a method for controlling the mixing of methanol and gas to improve the performance of a methanol engine specifically includes the following steps: S1. Read the calibration parameter threshold speed A; S2. Collect the actual engine speed N via EDU; S3. Determine whether the actual engine speed N is greater than the calibrated parameter threshold speed A. If the actual engine speed N is less than the calibrated parameter threshold speed A, then adopt a low-speed strategy, that is, adopt a vortex intake mode to control the second methanol injector to work and the first methanol injector to not work. When the actual engine speed N is greater than the calibrated parameter threshold speed A, a high-speed strategy is adopted, that is, the first methanol injector is controlled to work, the second methanol injector is stopped, and the premixed combustible mixture enters the cylinder through the parallel air passage.

[0023] In summary, this application monitors different engine speeds using the ECU and controls the operation of different injectors accordingly, thereby controlling the in-cylinder combustion mode. This can improve the in-cylinder combustion performance of methanol engines, increase engine thermal efficiency, and reduce the risk of knocking.

[0024] The number of devices and processing scale described herein are for simplification purposes. Applications, modifications, and variations of this invention will be readily apparent to those skilled in the art. Although embodiments of the invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for this invention, and further modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, this invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for controlling the mixing of methanol and gas to improve the performance of a methanol engine, characterized in that, A single-cylinder assembly applied to the method, the single-cylinder assembly comprising at least two air passages, each air passage having a methanol injector fixedly connected thereto; The control method includes the following steps: Obtain the engine's rotational state during operation; Determine whether the engine speed exceeds a preset value during operation; The control module adjusts the methanol injector's injection state based on the engine's rotation status, thereby controlling the in-cylinder combustion mode.

2. The method for controlling the mixing of methanol and gas to improve the performance of a methanol engine as described in claim 1, characterized in that, The single-cylinder assembly includes a cylinder body, on which two air passages are provided, and a first methanol injector and a second methanol injector are respectively fixedly connected to the two air passages.

3. The method for controlling the mixing of methanol and gas to improve the performance of a methanol engine as described in claim 2, characterized in that, The cylinder block has two air passages, specifically one parallel air passage and the other a spiral air passage.

4. The method for controlling the mixing of methanol and gas to improve the performance of a methanol engine as described in claim 3, characterized in that, A first methanol injector is fixedly connected to the parallel air passage, and a second methanol injector is fixedly connected to the spiral air passage.

5. The method for controlling the mixing of methanol and gas to improve the performance of a methanol engine as described in claim 1, characterized in that, The process of obtaining the engine's rotational state during operation specifically includes obtaining the engine's low-speed operation state and obtaining the engine's overspeed operation state.

6. A method for controlling the mixing of methanol and gas to improve the performance of a methanol engine as described in claim 1 or 5, characterized in that, The specific steps of adjusting the methanol injector injection state based on the engine's rotational state via the control module are as follows: When the generator is running at low speed, the control module controls the second methanol injector to work normally and controls the first methanol injector to be in the off state. When the generator is in overspeed operation, the control module controls the first methanol injector to operate normally and controls the second methanol injector to be in the off state.

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