Diesel-methanol in-cylinder direct injection engine plateau low-temperature starting control method and system
By utilizing the diesel-methanol direct injection technology and the combustion characteristics under different injection modes, the problem of unstable starting of diesel engines in high-altitude and low-temperature environments has been solved, achieving rapid starting and low emissions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TONGJI UNIV
- Filing Date
- 2025-11-27
- Publication Date
- 2026-05-29
AI Technical Summary
Diesel engines often experience long ignition delay, unstable ignition, or even misfire during starting in high-altitude, low-temperature environments, leading to starting failures.
It adopts diesel-methanol direct injection technology, which adjusts the dual-fuel injection mode under different engine operating conditions, and utilizes the high heat release rate of methanol and the ignition effect of diesel to achieve rapid combustion in the cylinder.
It enables rapid starting of diesel engines in high-altitude and low-temperature environments, reduces pollutant emissions, and improves engine starting reliability and thermal efficiency.
Smart Images
Figure CN122106770A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of road traffic emissions, and in particular to a method and system for controlling the low-temperature start-up of a diesel-methanol direct injection engine at high altitudes. Background Technology
[0002] The lower atmospheric temperature and pressure in high-altitude environments cause problems such as large speed fluctuations, high noise, and even misfires during the starting process of internal combustion engines (8669045). Compared to gasoline, which has high volatility and uses electric spark ignition, diesel fuel has low volatility and relies on compression ignition for self-ignition. When starting a diesel engine in a high-altitude environment, the cylinder pressure, temperature, and air-fuel mixture formation conditions are all worse, resulting in a much longer ignition delay period than in low-altitude conditions. This leads to unstable ignition and even misfires in diesel engines.
[0003] The starting process of an internal combustion engine refers to the process from a stable stationary state to high-speed rotation. By analyzing the instantaneous speed curve of the internal combustion engine during the starting process, the starting process can be divided into four stages: the dragging stage, the acceleration stage, the transition stage, and the stabilization stage. The dragging stage refers to the period from when the internal combustion engine starts to rotate under external force until the speed begins to rise spontaneously; the acceleration stage refers to the period from when the speed begins to rise spontaneously until it reaches its maximum value; the transition stage refers to the period from the maximum speed to the stable speed; and the stabilization stage refers to the period when the speed stabilizes at idle speed.
[0004] In high-altitude environments, diesel engines using compression ignition experience several cycles of misfire, leading to sluggishness or even engine stalling. The main reasons are: reduced air intake at high altitudes result in poorer fuel atomization; the starting process requires enrichment; and the rapid increase in engine speed significantly reduces the time for air-fuel mixture formation. Additionally, the low cylinder compression and wall temperatures during starting further exacerbate this. The reduced air intake at high altitudes also causes significantly lower cylinder compression pressure, further degrading the quality of the air-fuel mixture and leading to several consecutive misfire cycles, ultimately resulting in starting failure. The ignition delay period during engine starting is significantly longer at high altitudes than at low altitudes.
[0005] The diesel micro-ignition methanol direct injection technology adds a methanol injection system to an existing diesel engine to achieve direct methanol injection. When the piston approaches top dead center, a small amount of diesel fuel is injected directly into the cylinder. The diesel fuel ignites spontaneously, forming a flame that increases the temperature and pressure inside the combustion chamber. Subsequently, methanol fuel is injected directly into the combustion chamber through a high-pressure pipeline, achieving methanol diffusion combustion. The methanol injection phase is near top dead center, a late injection, which effectively avoids knocking, thus allowing for a higher compression ratio to improve thermal efficiency. This type of engine not only maintains the high thermal efficiency and low-speed torque of the original diesel engine but also significantly reduces NOx and soot emissions. The small amount of diesel fuel only serves as an ignition source; the vast majority of combustion is powered by methanol fuel.
[0006] Because methanol fuel has a low cetane number, current engines cannot achieve pure methanol starting by compression ignition alone. However, due to the long lag period of diesel compression ignition starting in the low-temperature environment of high altitude, the starting time is relatively long. Summary of the Invention
[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method and system for controlling the low-temperature start-up of a diesel-methanol direct injection engine at high altitudes. Utilizing the high heat release rate characteristic of the methanol-diesel mode, rapid in-cylinder combustion can be achieved during the engine's lag phase, thus achieving a rapid engine start-up effect. Simultaneously, the introduced polymer-dispersed liquid crystal layer can reversibly switch between transparent and scattering states under an applied electric field, enabling the device to further enable and disable optical information under voltage regulation. This dual regulation mechanism allows the device to not only perform high-fidelity color display and electrically driven dynamic printing, but also to encrypt and decrypt information through multi-dimensional parameter control. To achieve the above-mentioned objectives and other advantages of the present invention, a method for controlling the low-temperature start-up of a diesel-methanol direct injection engine at high altitudes is provided, comprising: This system is applied to the high-altitude, low-temperature start-up system for the diesel-methanol direct injection engine, which includes: A filter assembly, a dual-fuel pump connected to the filter assembly, a high-pressure distribution block connected to the dual-fuel pump, a methanol rail and a diesel rail connected to the high-pressure distribution block, and dual-fuel injectors connected to both the methanol rail and the diesel rail. The method includes the following steps: Obtain engine operating status; The control information for the dual-fuel injector is determined based on the operating status. The dual-fuel injector injection mode is adjusted based on the control information.
[0008] Preferably, the engine operating states include a start-up mode and an idle mode.
[0009] Preferably, the injection modes include pure diesel mode, diesel-methanol injection mode, and methanol-diesel injection mode.
[0010] Preferably, when the engine is in the start-up mode, the control information for the dual-fuel injector is as follows: the filter assembly filters the diesel fuel, the dual-fuel pump delivers the diesel fuel to the dual-fuel injector, and the diesel fuel is injected into the cylinder through the dual-fuel injector, thereby starting the engine by diesel fuel compression.
[0011] Preferably, when the engine is in idle mode, the control information for the dual-fuel injector is as follows: the filter assembly first filters the diesel fuel, the dual-fuel pump delivers the diesel fuel to the dual-fuel injector, and the diesel fuel is injected into the cylinder through the dual-fuel injector; after the diesel fuel is injected, the filter assembly then filters the methanol, the dual-fuel pump delivers the methanol to the dual-fuel injector, and the methanol is injected into the cylinder through the dual-fuel injector.
[0012] Preferably, if the engine experiences a lag period during startup, and the engine speed exceeds the starter motor's drag speed, the engine speed increase rate is less than a preset value for a period of time, and the engine is in startup mode, the control information for the dual-fuel injector is as follows: the filter assembly first filters the methanol, the dual-fuel pump delivers the methanol to the dual-fuel injector, and the methanol is injected into the cylinder through the dual-fuel injector; after the methanol is injected, the filter assembly then filters the diesel fuel, the dual-fuel pump delivers the diesel fuel to the dual-fuel injector, and the diesel fuel is injected into the cylinder through the dual-fuel injector.
[0013] Preferably, if the engine experiences a lag period during startup, and the engine speed exceeds the starter motor's drag speed, the engine speed increase rate is less than a preset value for a period of time, and the engine is in idle mode, the control information for the dual-fuel injector is as follows: the filter assembly first filters the diesel fuel, the dual-fuel pump delivers the diesel fuel to the dual-fuel injector, and the diesel fuel is injected into the cylinder through the dual-fuel injector; after the diesel fuel is injected, the filter assembly then filters the methanol, the dual-fuel pump delivers the methanol to the dual-fuel injector, and the methanol is injected into the cylinder through the dual-fuel injector.
[0014] Preferably, a device for a high-altitude low-temperature starting system for a diesel-methanol direct injection engine includes: The acquisition module is used to acquire the engine's operating status; A control information determination module is used to determine the control information of the dual-fuel injector based on the operating status. The injection adjustment module is used to adjust the injection mode of the dual-fuel injector according to the control information.
[0015] Compared with existing technologies, the advantages and positive effects of this invention are: by utilizing the combustion differences under different injection modes and based on the judgment of whether the engine speed is in a lag period, different injection control modes are adopted at different speed rise stages. This control method enables rapid engine start-up. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the high-altitude low-temperature start-up control method and system for a diesel-methanol direct injection engine according to the present invention; Figure 2A schematic diagram of the engine operation mode of the diesel-methanol direct injection engine high-altitude low-temperature start control method and system according to the present invention; Figure 3 This is a schematic diagram illustrating different injection modes of the diesel-methanol direct injection engine high-altitude low-temperature start-up control method and system according to the present invention. Detailed embodiments. 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.
[0017] Reference Figure 1 A high-altitude low-temperature starting system for a diesel-methanol direct injection engine, comprising: The components include a coarse filter 1, a fine filter 2 connected to the coarse filter 1, a methanol fuel pump 3 and a diesel fuel pump 4 connected to the fine filter 2, a high-pressure distribution block 5 connected to both the methanol fuel pump 3 and the diesel fuel pump 4, a methanol common rail 6 and a diesel common rail 7 connected to the high-pressure distribution block 5, and a methanol injector 8 and a diesel injector 9 connected to both the methanol common rail 6 and the diesel common rail 7.
[0018] Furthermore, the diesel-methanol direct injection engine high-altitude low-temperature start system is applied to the diesel-methanol direct injection engine high-altitude low-temperature start control method, which specifically includes the following steps: Obtain engine operating status; The control information for the dual-fuel injector is determined based on the operating status. The dual-fuel injector injection mode is adjusted based on the control information.
[0019] Furthermore, when the monitoring module monitors the engine in a high-altitude, low-temperature environment, and the acquisition module determines that the engine is in start-up mode, the control information determination module transmits the acquired information to the injection adjustment module. The injection adjustment module adjusts the following information: the coarse filter 1 performs preliminary filtration of the diesel fuel, and then the fine filter 2 performs fine filtration of the diesel fuel. The diesel fuel pump 4 delivers the diesel fuel to the diesel injector 9, and the diesel fuel is injected into the cylinder through the diesel injector 9. The engine starts by relying on the compression of the diesel fuel.
[0020] Furthermore, when the monitoring module detects that the engine is in a high-altitude, low-temperature environment, the acquisition module determines that the engine is in idle mode. The control information determination module then transmits the acquired information to the injection adjustment module. The injection adjustment module adjusts the following information: the coarse filter 1 performs preliminary filtration of diesel fuel, followed by fine filtration of diesel fuel through the fine filter 2. The diesel fuel pump 4 delivers diesel fuel to the diesel injector 9, through which diesel fuel is injected into the cylinder. After the diesel fuel is injected, the coarse filter 1 performs preliminary filtration of methanol, followed by fine filtration of methanol fuel through the fine filter 2. The methanol fuel pump 3 delivers methanol fuel to the methanol injector 8, through which methanol fuel is injected into the cylinder.
[0021] like Figure 3 As shown, during the stagnation period: in the acceleration phase of an internal combustion engine's start-up process, the instantaneous speed stops rising and remains near a certain speed. TDC represents top dead center, and from left to right, it indicates that diesel fuel is injected first as ignition before top dead center, followed by methanol fuel as the main fuel; The second diagram shows methanol being injected before the top dead center, diesel being injected simultaneously, and then methanol being injected again. The third diagram shows multiple methanol injections: a small amount of methanol is injected before top dead center, followed by a small amount of diesel fuel, and finally a large amount of methanol. During the lag phase of the starting process, a cycle of no combustion pressure rise occurs, which prolongs the starting time of the internal combustion engine. The injection pattern is as follows: 1. Diesel-Methanol Mode: Diesel is injected first, followed by methanol, with a large amount of methanol injected. In this mode, diesel is only used as an ignition source, accounting for less than 10% of combustion, while methanol is the primary fuel.
[0022] 2. Methanol-Diesel Mode: Methanol is continuously injected, while diesel is injected at a certain time.
[0023] 3. Methanol-Diesel-Methanol Mode: A portion of methanol is pre-injected, followed by diesel, and finally methanol. In this mode, a large quantity of methanol is injected. It has a high heat release rate, enabling rapid and intense combustion within the engine cylinder.
[0024] Furthermore, if the engine experiences a lag period during startup, i.e., the engine speed is in the n0-n1 range, and the monitoring module detects that the engine speed exceeds the starter motor's drag speed, while the engine speed increase rate is less than a preset value for a period of time, and the acquisition module determines that the engine is in startup mode, the control information determination module will transmit the acquired information to the injection adjustment module. The injection adjustment module adjusts the following: the coarse filter 1 performs preliminary filtration of methanol, followed by fine filtration of methanol through the fine filter 2; the methanol fuel pump 3 delivers methanol to the methanol injector 8, through which methanol is injected into the cylinder; after methanol injection, the coarse filter 1 performs preliminary filtration of diesel fuel, followed by fine filtration of diesel fuel through the fine filter 2; the diesel fuel pump 4 delivers diesel fuel to the diesel injector 9, through which diesel fuel is injected into the cylinder. Utilizing the relatively high oxygen content of methanol fuel and the high heat release rate in the methanol-to-diesel mode, rapid combustion of the combustible mixture in the cylinder is achieved.
[0025] Furthermore, during engine startup, a lag period occurs, where the engine speed is in the n0-n1 range (n0 speed ≤ 200 r / min, n0-n1 speed range 200-500 r / min). When the monitoring module detects that the engine speed exceeds the starter motor's drag speed, and the engine speed increase rate is less than a preset value for a period of time, and the acquisition module determines that the engine is in idle mode (i.e., the engine speed is after n2, n1-n2 speed range 500-1200 r / min), the control information determination module transmits the acquired information to the injection adjustment module. The injection adjustment module adjusts the following: the coarse filter 1 performs preliminary filtration of diesel fuel, followed by fine filtration of diesel fuel through the fine filter 2; the diesel fuel pump 4 delivers diesel fuel to the diesel injector 9, through which diesel fuel is injected into the cylinder; after the diesel fuel is injected, the coarse filter 1 performs preliminary filtration of methanol, followed by fine filtration of methanol fuel through the fine filter 2; the methanol fuel pump 3 delivers methanol to the methanol injector 8, through which methanol is injected into the cylinder.
[0026] Furthermore, a device for a high-altitude, low-temperature starting system for a diesel-methanol direct injection engine includes: The acquisition module is used to acquire the engine's operating status; A control information determination module is used to determine the control information of the dual-fuel injector based on the operating status. The injection adjustment module is used to adjust the injection mode of the dual-fuel injector according to the control information. Furthermore, electronic devices are intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.
[0027] Furthermore, an electronic device includes: at least one processor; and a memory, such as a read-only memory (ROM) or a random access memory (RAM), communicatively connected to the at least one processor. The memory stores a computer program executable by the at least one processor, which can perform various appropriate actions and processes based on the computer program stored in the ROM or loaded from a storage unit into the RAM. The RAM may also store various programs and data required for the operation of the electronic device; wherein the memory stores a computer program executable by the at least one processor, which is executed by the at least one processor to enable the at least one processor to execute the control method for the high-altitude low-temperature start-up system of the diesel-methanol direct injection engine.
[0028] Furthermore, the processor, read-only memory (ROM), and random access memory (RAM) are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus. Multiple components in the electronic device are connected to the I / O interfaces, including: input units such as a keyboard, mouse, etc.; output units such as various types of displays, speakers, etc.; storage units such as disks, optical discs, etc.; and communication units such as network interface cards, modems, wireless transceivers, etc. The communication units allow the electronic device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks. Processor 11 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. The processor executes the various methods and processes described above, such as the control method for a high-altitude, low-temperature start-up system of a diesel-methanol direct injection engine. In some embodiments, the control method for a high-altitude, low-temperature start-up system of a diesel-methanol direct injection engine can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as a storage unit. In some embodiments, part or all of the computer program can be loaded into and / or installed on an electronic device via a read-only memory (ROM) and / or a communication unit. When the computer program is loaded into random access memory (RAM) and executed by a processor, one or more steps of the control method for a high-altitude, low-temperature start-up system of a diesel-methanol direct injection engine described above can be performed. Alternatively, in other embodiments, the processor can be configured to perform the control method for a high-altitude, low-temperature start-up system of a diesel-methanol direct injection engine by any other suitable means (e.g., by means of firmware).
[0029] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.
[0030] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.
[0031] The number of devices and processing scale described herein are for simplification of the invention. 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 low-temperature start-up of a diesel-methanol direct injection engine at high altitudes, characterized in that, include: This system is applied to the high-altitude, low-temperature start-up system for the diesel-methanol direct injection engine, which includes: A filter assembly, a dual-fuel pump connected to the filter assembly, a high-pressure distribution block connected to the dual-fuel pump, a methanol rail and a diesel rail connected to the high-pressure distribution block, and dual-fuel injectors connected to both the methanol rail and the diesel rail. The method includes the following steps: Obtain engine operating status; The control information for the dual-fuel injector is determined based on the operating status. The dual-fuel injector injection mode is adjusted based on the control information.
2. The method for controlling the low-temperature start-up of a diesel-methanol direct injection engine at high altitudes as described in claim 1, characterized in that, The engine operating states include start-up mode and idle mode.
3. The method for controlling the low-temperature start-up of a diesel-methanol direct injection engine at high altitudes as described in claim 1, characterized in that, The injection modes include pure diesel mode, diesel-methanol injection mode, and methanol-diesel injection mode.
4. A method for controlling the low-temperature start-up of a diesel-methanol direct injection engine at high altitudes as described in claim 3 or 2, characterized in that, When the engine is in start-up mode, the control information for the dual-fuel injector is as follows: the filter assembly filters the diesel fuel, the dual-fuel pump delivers the diesel fuel to the dual-fuel injector, and the diesel fuel is injected into the cylinder through the dual-fuel injector, thereby starting the engine by diesel fuel compression.
5. The method for controlling the low-temperature start-up of a diesel-methanol direct injection engine at high altitudes as described in claim 4, characterized in that, When the engine is in idle mode, the control information for the dual-fuel injector is as follows: the filter assembly first filters the diesel fuel, the dual-fuel pump delivers the diesel fuel to the dual-fuel injector, and the diesel fuel is injected into the cylinder through the dual-fuel injector; after the diesel fuel is injected, the filter assembly then filters the methanol, the dual-fuel pump delivers the methanol to the dual-fuel injector, and the methanol is injected into the cylinder through the dual-fuel injector.
6. The method for controlling the low-temperature start-up of a diesel-methanol direct injection engine at high altitudes as described in claim 5, characterized in that, If the engine experiences a lag period during startup, and the engine speed exceeds the starter motor's drag speed, the engine speed increase rate is less than a preset value for a period of time, and the engine is in startup mode, the control information for the dual-fuel injector is as follows: the filter assembly first filters the methanol, the dual-fuel pump delivers the methanol to the dual-fuel injector, and the methanol is injected into the cylinder through the dual-fuel injector; after the methanol is injected, the filter assembly then filters the diesel, the dual-fuel pump delivers the diesel to the dual-fuel injector, and the diesel is injected into the cylinder through the dual-fuel injector.
7. The method for controlling the low-temperature start-up of a diesel-methanol direct injection engine at high altitudes as described in claim 6, characterized in that, If the engine experiences a lag period during startup, and the engine speed exceeds the starter motor's drag speed, the engine speed increase rate is less than a preset value for a period of time, and the engine is in idle mode, the control information for the dual-fuel injector is as follows: the filter assembly first filters the diesel fuel, the dual-fuel pump delivers the diesel fuel to the dual-fuel injector, and the diesel fuel is injected into the cylinder through the dual-fuel injector; after the diesel fuel is injected, the filter assembly then filters the methanol, the dual-fuel pump delivers the methanol to the dual-fuel injector, and the methanol is injected into the cylinder through the dual-fuel injector.
8. A device for a high-altitude, low-temperature starting system for a diesel-methanol direct injection engine, characterized in that, The control method for starting a diesel-methanol direct injection engine at high altitude and low temperature, as described in any one of claims 1-7, includes: The acquisition module is used to acquire the engine's operating status; A control information determination module is used to determine the control information of the dual-fuel injector based on the operating status. The injection adjustment module is used to adjust the injection mode of the dual-fuel injector according to the control information.
9. An electronic device, characterized in that, The electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the high-altitude low-temperature start control method for a diesel-methanol direct injection engine as described in any one of claims 1-7.