Methanol engine and control method

Abstract

Disclosed in the present invention is a methanol engine. The methanol engine comprises a methanol fuel system, a compression-ignition engine and an electronic control unit, wherein on the basis of a collected operating condition, the electronic control unit controls the methanol fuel system to inject fuel into a cylinder of the compression-ignition engine. The methanol engine is characterized by further comprising a temperature-controllable hot-surface combustion-supporting system in communication connection with the electronic control unit, wherein the hot-surface combustion-supporting system heats methanol sprayed into the cylinder and adjusts a heating temperature on the basis of the operating condition. The present invention has the advantages of performing autonomous temperature measurement and accurate temperature control, being unaffected by operating conditions and environmental changes, having a long service life, being less prone to aging, etc.; the present invention fills in the gaps of reliable ignition and running in stable operating conditions where existing methanol engines cannot use 100% of methanol fuel; moreover, 30-50% of fuel costs are reduced, and the heat efficiency reaches up to 47% or more; and the emission of a pure methanol automobile is free of soot, such that the emission of NOx is reduced by 45%. Further provided in the present invention is a control method for a methanol engine.

Description

Methanol engine and control method Technical Field

[0001] The present invention relates to a methanol engine, in particular to a methanol engine with a hot surface combustion-supporting system and a control method thereof. Background Art

[0002] Methanol, as a new clean energy source, can replace gasoline and diesel and is used in various vehicles and stoves. The raw materials for methanol production primarily include coal, natural gas, coalbed methane, and coke oven gas. The use of high-sulfur, low-quality coal and coke oven gas to produce methanol, in particular, improves resource utilization while reducing environmental pollution. Compression-ignition engines offer the advantages of high torque, high power, high energy density, and high thermal efficiency, but they cannot directly ignite clean fuels such as pure methanol, LNG, and ammonia.

[0003] Chinese patent document CN101629533A discloses a methanol engine fuel supply system, comprising a methanol fuel injector (1), a methanol fuel pump (7), a methanol fuel tank (8), a methanol fuel rail (5), an intake manifold assembly (15), and a throttle body assembly (14). The system is characterized in that the fuel supply system is further provided with a gasoline supply device, comprising a small gasoline tank (10), a gasoline pump (11) located in the small gasoline tank, a small gasoline rail (13), and at least one gasoline injector (12) mounted on the small gasoline rail (13). A control method for the fuel supply system is also disclosed. The present invention has the advantages of simple structure, convenient operation, high reliability, and ease of implementation, effectively solving the problem of difficult low-temperature starting of a methanol engine.

[0004] Another Chinese patent document CN206555044U discloses a methanol engine fuel supply system, including a main fuel supply system and an auxiliary fuel supply system, an intake manifold and a cylinder block, the main fuel supply system including a methanol tank, a methanol pump, a methanol rail and a methanol injector, the auxiliary fuel supply system including a gasoline tank, a gasoline pump, a gasoline rail and a gasoline injector, the methanol injector is connected to the methanol pump via the methanol rail, and the gasoline injector is connected to the gasoline pump via the gasoline rail; the gasoline injector is installed on the intake manifold and communicates with the intake duct through the intake manifold, the gasoline injector is used to inject gasoline into the intake duct when the engine is started and stop injecting gasoline into the intake duct after the engine is successfully started; the methanol injector is installed on the cylinder head of the cylinder block and communicates with the cylinder through the cylinder head, and the methanol injector is used to start injecting methanol into the cylinder after the engine is successfully started.

[0005] While the two aforementioned Chinese patents demonstrate the ability to ignite methanol fuel, neither directly ignites the methanol. Instead, they employ gasoline as a secondary fuel, initially igniting the engine with gasoline before introducing methanol as fuel to generate power. This dual-fuel approach offers limited fuel cost savings, limited emission reductions, and is also expensive.

[0006] Summary of the Invention

[0007] In order to solve the technical problem in the prior art that methanol engines require gasoline fuel when starting, which easily causes emissions to exceed standards, the present invention provides a methanol engine, including a methanol fuel system, a compression ignition engine and an electronic control unit. The electronic control unit controls the methanol fuel system to spray fuel into the cylinder of the compression ignition engine according to the collected working conditions. The invention is characterized in that it also includes a temperature-controllable hot surface combustion-supporting system communicatively connected to the electronic control unit. The hot surface combustion-supporting system heats the methanol sprayed into the cylinder and adjusts the heating temperature according to the working conditions.

[0008] In this solution, the methanol injected into the cylinder is heated by a temperature-controllable hot surface combustion-supporting system. The heated methanol is heated and ignited to produce work. At the same time, the temperature in the cylinder also rises, causing the fuel in other parts of the combustion chamber where the cylinder is located to be compressed and ignited to produce work. Compared with the dual-fuel starting method used in the prior art, this solution can achieve reliable ignition and stable operation of the methanol engine under the condition of 100% using methanol fuel, while saving fuel costs by 30-50% and achieving a thermal efficiency of more than 47%. Pure methanol vehicles emit no carbon smoke and reduce NOx emissions by 45%.

[0009] Preferably, the hot surface combustion support system includes a temperature-controllable heating element and a controller communicating with an electronic control unit. The controller controls the heating temperature of the temperature-controllable heating element based on operating conditions. In this solution, the controller and the temperature-controllable heating element work together to timely adjust the heating temperature of the hot surface combustion support system, ensuring reliable engine ignition while also extending the service life of the hot surface combustion support system.

[0010] The methanol fuel system preferably includes a fuel tank, a fuel transfer pump, a high-pressure common rail, and a fuel injector. The fuel injector extends into the cylinder. The methanol in the fuel tank is converted into high-pressure oil by the fuel transfer pump and transported to the high-pressure common rail, where it is then ejected through the fuel injector. In this solution, the use of a high-pressure common rail fuel supply eliminates the need for a pressurizing mechanism within the injector, thereby reducing engine costs. Furthermore, the common rail cavity maintains a constant high pressure, requiring a significantly lower driving torque than a traditional fuel pump.

[0011] Preferably, the fuel delivery pump includes a low-pressure auxiliary pump and a high-pressure pump. The low-pressure auxiliary pump pumps methanol from the fuel tank to the low-pressure port of the high-pressure pump. The high-pressure pump plunger then converts the methanol into high-pressure oil and supplies it to the high-pressure common rail. Given the low viscosity of methanol, the low-pressure auxiliary pump is also included in this solution to ensure smooth delivery of methanol fuel, thereby ensuring smooth operation of the methanol engine.

[0012] Preferably, a filter is provided on the oil path between the low-pressure auxiliary pump and the high-pressure pump. In this solution, the filter is used to remove impurities and water in the methanol, preventing these impurities from entering the engine, thereby protecting the engine and extending its life.

[0013] Preferably, a return line is provided between the high-pressure pump and the fuel tank. As the high-pressure pump supplies methanol to the high-pressure common rail, excess methanol in the pump returns to the fuel tank through the return line. In this solution, the return line ensures the circulation of methanol fuel and prevents excess methanol fuel from accumulating in the fuel line.

[0014] The methanol fuel system's oil circuit is preferably equipped with a metering unit capable of adjusting the oil flow rate. Considering that the power requirements of a methanol engine vary under different operating conditions, this solution utilizes a metering unit to adjust the oil flow rate, allowing the methanol engine to adapt to varying operating conditions while maintaining a simple structure.

[0015] Preferably, the high-pressure moving parts of the methanol fuel system are provided with a protective layer. The provision of the protective layer in this solution can extend the service life of the high-pressure moving parts.

[0016] Preferably, the methanol fuel system's fuel lines utilize oil expansion- and pressure-resistant tubing and seals, and the fuel tank and / or filter utilize corrosion-resistant materials to extend their service life.

[0017] Preferably, the injection hole of the fuel injector is a large-aperture injection hole. Considering that the calorific value of methanol is much lower than that of diesel, the large-aperture injection hole in this solution can increase the amount of methanol injected to ensure sufficient output power of the engine.

[0018] Preferably, the electronic control unit controls the methanol injection nozzle based on the injection pulse width and injection advance angle calculated based on the operating conditions. In this solution, the electronic control unit controls the injection nozzle based on the operating conditions to ensure reliable ignition, stable operation, and a longer service life for the methanol engine.

[0019] In a second aspect, the present invention also provides a control method for a methanol engine, which adopts the above-mentioned methanol engine; the method comprises the following contents: the methanol in the fuel tank is converted into high-pressure oil by an oil pump and transported to a high-pressure common rail; the electronic control unit controls the injector to spray fuel into the cylinder of the compression ignition engine after obtaining the injection pulse width and injection advance angle according to the collected working conditions, the temperature-controllable electronic component is continuously energized and heated during the operation of the compression ignition engine, and the controller controls the heating temperature of the temperature-controllable heating element according to the working conditions and heats the methanol injected into the cylinder.

[0020] The present invention has the following beneficial effects:

[0021] 1. After the hot surface combustion-supporting system is installed in the present invention, it has the advantages of self-temperature measurement and precise temperature control, is not affected by changes in working conditions and environment, has a long service life and is not easy to age. It fills the gap of existing methanol engines that cannot reliably ignite and operate stably under the condition of 100% use of methanol fuel. At the same time, fuel costs are saved by 30-50% and the thermal efficiency is as high as 47% or more. Pure methanol vehicles emit no carbon smoke and NOx emissions are reduced by 45%.

[0022] 2. The present invention replaces and processes the easily corroded and easily worn parts of the methanol fuel system, thereby extending the service life of the methanol fuel system.

[0023] 3. The present invention partially adjusts the flow cross-sectional area of ​​the fuel injector and the control parameters of the electronic control unit to ensure reliable ignition and stable operation of the methanol engine and a longer service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a schematic diagram of a methanol fuel system in a methanol engine according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following is further described in detail through specific implementation methods:

[0026] 1. Definition

[0027] Electronic Control Unit, ECU, or onboard computer, consists of a microcontroller and peripheral circuits.

[0028] A compression ignition engine is an internal combustion engine that does not rely on spark ignition, but instead relies on the high temperature and high pressure of the charge in the cylinder at the end of compression to cause the mixture to self-ignite.

[0029] Controllable temperature heating element: A heating element with self-temperature measurement and precise temperature control, using a controllable temperature electric glow plug.

[0030] High-pressure common rail: Electronic fuel injection (EFI) technology completely separates the generation of injection pressure from the injection process within a closed-loop system consisting of a high-pressure fuel pump, pressure sensor, and electronic control unit (ECU). Common rail technology involves the high-pressure fuel pump delivering high-pressure fuel to a common fuel supply line. By precisely controlling the oil pressure within the common fuel supply line, the pressure in the high-pressure fuel line is independent of engine speed, significantly reducing the variation in diesel engine fuel supply pressure with engine speed, thereby alleviating the defects of traditional diesel engines. The ECU controls the injection volume of the injector, which is determined by the pressure in the fuel rail (common fuel supply line) and the duration of the solenoid valve opening.

[0031] Injection pulse width: refers to the length of time that the engine's onboard computer controls the injector to spray fuel each time. It is the most important indicator of whether the engine's injector is working properly.

[0032] Injection advance angle: refers to the crankshaft angle from the moment the injector starts to spray fuel into the cylinder (marked by the extension of the injector needle valve) to the top dead center of the piston when the engine is running.

[0033] 2. The reference numerals in the drawings of the specification include: fuel tank 1, low-pressure auxiliary pump 2, filter 3, metering unit 4, high-pressure pump plunger 5, high-pressure pump 6, control unit 7, temperature-controllable heating element 8, high-pressure common rail 9, pressure sensor 10, fuel injector 11, and compression ignition engine 12.

[0034] The embodiment is generally shown in FIG1 : a methanol engine comprising a methanol fuel system, a compression ignition engine 12, an electronic control unit 7, and a temperature-controllable hot surface combustion system in communication with the electronic control unit 7. The electronic control unit 7 controls the methanol fuel system to inject fuel into the cylinders of the compression ignition engine 12 based on the collected operating conditions. The hot surface combustion system heats the methanol injected into the cylinders and adjusts the heating temperature based on the operating conditions. The operating conditions are collected by a pressure sensor 10 mounted on the high-pressure common rail 9 and other sensors in communication with the electronic control unit 7, including pressure signals, the speed of the compression ignition engine 12, and the water temperature.

[0035] Specifically, the methanol fuel system includes a fuel tank 1, a fuel delivery pump, a high-pressure common rail 9, fuel injectors 11, and the oil circuits between these components. The fuel delivery pump includes a low-pressure auxiliary pump 2 and a high-pressure pump 6. A filter 3 and a metering unit 4 are provided in the oil circuit between the low-pressure auxiliary pump 2 and the high-pressure pump 6. A return oil line is provided between the high-pressure pump 6 and the fuel tank 1. The low-pressure auxiliary pump 2 pumps methanol from the fuel tank 1 to the low-pressure end of the high-pressure pump 6. The high-pressure pump plunger 5 of the high-pressure pump 6 generates high pressure for supply to the high-pressure common rail 9. The low-pressure auxiliary pump 2 pumps methanol from the fuel tank 1 to the low-pressure end of the high-pressure pump 6. The high-pressure pump plunger 5 of the high-pressure pump 6 generates high pressure for supply to the high-pressure common rail 9, and then sprays it through the fuel injectors 11. As the high-pressure pump 6 supplies methanol to the high-pressure common rail 9, excess methanol in the high-pressure pump 6 returns to the fuel tank 1 through the return oil line.

[0036] The methanol fuel system's high-pressure moving components are protected by a protective layer. The system's oil circuit utilizes oil expansion- and pressure-resistant tubing and seals. The fuel tank 1 and / or filter 3 utilize corrosion-resistant components. High-pressure moving components include the high-pressure pump plunger assembly, the injector needle valve, and the one-way ball valve.

[0037] The hot surface combustion supporting system includes a temperature-controllable heating element 8 and a controller communicating with an electronic control unit 7 , and the controller controls the heating temperature of the temperature-controllable heating element 8 according to the working conditions.

[0038] The electronic control unit 7 controls the fuel injector 11 to spray methanol according to the injection pulse width and injection advance angle calculated according to the working conditions.

[0039] Based on the above-mentioned methanol engine, this embodiment also discloses a control method for a methanol engine, which includes the following contents: methanol in the fuel tank is converted into high-pressure oil by an oil pump and transported to a high-pressure common rail; an electronic control unit controls the fuel injector to spray fuel into the cylinder of the compression ignition engine after obtaining the injection pulse width and injection advance angle according to the collected working conditions; a temperature-controllable electronic component is continuously energized and heated during the operation of the compression ignition engine; and a controller controls the heating temperature of the temperature-controllable heating element according to the working conditions and heats the methanol injected into the cylinder.

[0040] The specific implementation process is as follows: When the methanol engine is running, the low-pressure auxiliary pump 2 pumps the methanol in the fuel tank 1 through the filter 3 and metering unit 4, and then supplies it to the low-pressure end of the high-pressure pump 6. The high-pressure pump plunger 5 then converts the methanol into high-pressure oil and supplies it to the high-pressure common rail 9. During this process, the excess oil returns to the fuel tank 1 through the return line.

[0041] The electronic control unit 7 collects the pressure signal through the pressure sensor 10, as well as the speed, operating conditions and other signals of the compression ignition engine 12, and then converts the injection pulse width and injection advance angle of the injector 11, and then controls the injector 11 to spray methanol into the cylinder according to the injection pulse width and injection advance angle.

[0042] During the operation of the methanol engine, the hot surface combustion support system is continuously powered on and generates heat. The controller controls the heating temperature of the temperature-controllable heating element 8 according to the operating conditions to ensure that the methanol injected into the cylinder is ignited and the temperature in the cylinder rises, causing the fuel in other places in the combustion chamber to be compressed and ignited to perform work.

[0043] The above is only an embodiment of the present invention. Common knowledge such as the known specific structures and characteristics in the scheme is not described in detail here. Ordinary technicians in the field are aware of all common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all existing technologies in the field, and have the ability to apply conventional experimental means before that date. Ordinary technicians in the field can improve and implement this scheme in combination with their own abilities under the inspiration given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A methanol engine, comprising a methanol fuel system, a compression ignition engine and an electronic control unit, wherein the electronic control unit controls the methanol fuel system to spray fuel into a cylinder of the compression ignition engine according to the collected working conditions; Features: It also includes a temperature-controllable hot surface combustion-supporting system that is communicatively connected to the electronic control unit, and the hot surface combustion-supporting system heats the methanol injected into the cylinder and adjusts the heating temperature according to the working conditions.

2. The methanol engine according to claim 1, Features: The hot surface combustion supporting system comprises a temperature-controllable heating element and a controller communicating with the electronic control unit, wherein the controller controls the heating temperature of the temperature-controllable heating element according to the working conditions.

3. The methanol engine according to claim 1 or 2, Features: The methanol fuel system comprises a fuel tank, a fuel delivery pump, a high-pressure common rail and a fuel injector. The fuel injector extends into the cylinder. The methanol in the fuel tank is transformed into high-pressure oil by the fuel delivery pump and transported to the high-pressure common rail and then sprayed out through the fuel injector.

4. The methanol engine according to claim 3, Features: The oil delivery pump includes a low-pressure auxiliary pump and a high-pressure pump. The low-pressure auxiliary pump pumps methanol in the fuel tank to the low-pressure end of the high-pressure pump. The high-pressure pump plunger of the high-pressure pump converts methanol into high-pressure oil and supplies it to the high-pressure common rail.

5. The methanol engine according to claim 4, Features: A filter is provided on the oil circuit between the low-pressure auxiliary pump and the high-pressure pump.

6. The methanol engine according to claim 5, Features: An oil return pipeline is provided between the high-pressure pump and the fuel tank. When the high-pressure pump supplies methanol to the high-pressure common rail, excess methanol in the high-pressure pump returns to the fuel tank through the oil return pipeline.

7. The methanol engine according to claim 6, Features: The oil circuit of the methanol fuel system is also provided with a metering unit capable of adjusting the amount of delivered oil.

8. The methanol engine according to claim 7, Features: The high-pressure moving parts of the methanol fuel system are provided with a protective layer.

9. The methanol engine according to claim 8, Features: The oil circuit of the methanol fuel system adopts oil expansion-resistant and oil pressure-resistant oil pipes and seals, the oil tank adopts a corrosion-resistant oil tank and / or the filter adopts a corrosion-resistant filter.

10. The methanol engine according to claim 9, Features: The fuel injection hole of the fuel injection nozzle adopts a large-diameter fuel injection hole.

11. The methanol engine according to claim 10, Features: The electronic control unit controls the fuel injector to spray methanol according to the injection pulse width and injection advance angle calculated according to the operating condition.

12. A method for controlling a methanol engine, Features: A methanol engine as described in any one of claims 1 to 11 is used; the following contents are included: methanol in a fuel tank is transported to a high-pressure common rail by an oil transfer pump in the form of high-pressure oil; an electronic control unit controls a fuel injector to spray fuel into a cylinder of a compression ignition engine after obtaining a fuel injection pulse width and a fuel injection advance angle according to the collected working conditions, a temperature-controllable electronic component is continuously powered on to generate heat during the operation of the compression ignition engine, and a controller controls the heating temperature of the temperature-controllable heating component according to the working conditions and heats the methanol injected into the cylinder.

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