Pure methanol engine low temperature cold start auxiliary system and method

Abstract

The present invention provides a low-temperature cold start auxiliary system and method for a pure methanol engine, the system includes a control unit, a coolant sensing component, an intake heating control component, a pre-combustion chamber heating control component and a methanol enrichment injector; the coolant sensing component is used to measure the temperature of the coolant in the engine; the intake heating control component includes a first heating structure and a second temperature sensor, the first heating structure heats the air in the gas pipeline; the pre-combustion chamber heating control component includes a second heating structure and a third temperature sensor, the second heating structure heats the pre-combustion chamber; the methanol enrichment injector is used to spray methanol into the pre-combustion chamber in multiple stages. Through this application, the temperature in the pre-combustion chamber is quickly increased during cold start, the spray effect of methanol under cold start is improved, the proportion of methanol in the mixed gas is increased, the problem that the methanol equivalence ratio is too low and ignition cannot be successful during cold start of a pure methanol engine is solved, and the engine is ensured to start quickly and smoothly during cold start.

Description

Technical Field

[0001] The present invention relates to the technical field of pure methanol engines, and in particular to a low-temperature cold start auxiliary system and method for a pure methanol engine. Background Art

[0002] At present, the two mature methanol engine technologies used in China include "methanol intake port injection + spark plug ignition" and "methanol intake port injection + diesel in-cylinder ignition". The "methanol intake port injection + spark plug ignition" type engine is limited by ignition energy and knock, has a small compression ratio and low thermal efficiency. The "methanol intake port injection + diesel in-cylinder ignition" type engine is prone to misfire due to the use of diesel in-cylinder ignition. In addition, this type of engine has a low methanol substitution rate, is limited by knock, and has high THC and CO emissions.

[0003] The existing pre-combustion chamber combustion system divides the combustion area into a pre-combustion chamber and a main combustion chamber. A slightly richer mixture is supplied in the pre-combustion chamber. After being ignited by the spark plug, the high-pressure and high-temperature flame will quickly enter the main combustion chamber in the form of a jet through the pre-combustion chamber nozzle, causing the lean mixture therein to burn and generating stronger disturbances, thereby increasing the combustion speed of the methanol mixture, significantly shortening the main combustion period, extending the lean burn limit, improving thermal efficiency, and achieving efficient combustion.

[0004] However, methanol has a high boiling point (methanol: 64.7°C, gasoline 32-210°C) and a large latent heat of vaporization (methanol: 1109 kJ / kg, gasoline 293-315 kJ / kg). During the cold start stage, due to the narrow space in the precombustion chamber, the methanol in the precombustion chamber will quickly condense into larger methanol droplets attached to the wall after hitting the wall, resulting in poor atomization effect. As a result, the methanol equivalence ratio in the gas atmosphere in the precombustion chamber cannot meet the ignition conditions, causing misfires and accumulating more methanol droplets in the precombustion chamber. When the ignition is successful again, the mixture burns incompletely, and the pollutant emissions surge. At the same time, it will cause carbon deposits in the precombustion chamber, blocking the spray holes between the precombustion chamber and the main combustion chamber, aggravating the problem of cold start difficulties in pure methanol engines in the precombustion chamber. Summary of the invention

[0005] Based on this, the purpose of the present invention is to provide a low-temperature cold start assist system and method for a pure methanol engine to address the deficiencies in the prior art.

[0006] To achieve the above object, the present invention provides a pure methanol engine low-temperature cold start auxiliary system, comprising a control unit and a coolant sensing component, an intake air heating control component, a pre-combustion chamber heating control component and a methanol enrichment injector electrically connected to the control unit;

[0007] The coolant sensing component is a first temperature sensor, which is used to measure the temperature of the coolant in the engine, so that the control unit can regulate the intake heating control component and the pre-combustion chamber heating control component based on the temperature of the coolant;

[0008] The intake air heating control assembly comprises a first heating structure and a second temperature sensor provided on the gas pipeline, wherein the intake air temperature of the gas pipeline is measured by the second temperature sensor, so that the first heating structure heats the air in the gas pipeline based on the intake air temperature;

[0009] The pre-combustion chamber heating control assembly comprises a second heating structure and a third temperature sensor provided on the pre-combustion chamber shell, and the temperature of the pre-combustion chamber shell is measured by the third temperature sensor, so that the second heating structure heats the pre-combustion chamber;

[0010] The methanol enrichment injector is located in the precombustion cavity of the precombustion chamber, and is used to inject methanol into the precombustion chamber in multiple stages at a preset equivalence ratio according to the temperature of the air in the gas pipeline and the temperature of the precombustion chamber;

[0011] Wherein, the pre-combustion chamber is located in the cylinder head of the engine, the pre-combustion chamber is connected to the exhaust end of the gas pipeline, and the first temperature sensor is located in the cooling water jacket of the engine.

[0012] The beneficial effects of the present invention are as follows: the temperature of the coolant in the engine is measured by the coolant sensing component, and the control unit can regulate the intake heating control component and the precombustion chamber heating control component based on the temperature of the coolant, so that the intake heating control component and the precombustion chamber heating control component heat the gas pipeline and the precombustion chamber respectively. When the temperature of the air in the gas pipeline and the temperature in the precombustion chamber reach a certain value, the control unit will drive the methanol enrichment injector to perform multi-stage injection into the precombustion chamber at a preset equivalence ratio, so as to quickly increase the temperature in the precombustion chamber during cold start, improve the spray effect of methanol under cold start, increase the proportion of methanol in the mixed gas, solve the problem that the methanol equivalence ratio of a pure methanol engine is too low to ignite successfully during cold start, ensure that the engine can start quickly and smoothly during cold start, and prevent the phenomenon of excessive methanol droplets accumulating in the precombustion chamber, thereby preventing the problem of carbon accumulation in the precombustion chamber to block the spray hole between the precombustion chamber and the main combustion chamber.

[0013] Preferably, the control unit includes a pre-combustion chamber shell temperature-intake air temperature MAP, and the pre-combustion chamber shell temperature-intake air temperature MAP is used to query the heating time and heating current intensity of the first heating structure and the second heating structure.

[0014] Preferably, a rotation speed sensor is installed on the engine, and the rotation speed sensor is used to monitor the rotation speed of the engine.

[0015] Preferably, the air inlet end of the gas pipeline, the first heating structure and the second temperature sensor are arranged in sequence along the axial direction of the gas pipeline.

[0016] Preferably, the pure methanol engine low-temperature cold start assist system also includes a battery, and the coolant sensing component, the intake air heating control component and the pre-combustion chamber heating control component are all electrically connected to the battery.

[0017] To achieve the above object, the present invention further provides a pure methanol engine low temperature cold start assist method, which is applicable to the pure methanol engine low temperature cold start assist system described above, and the method comprises:

[0018] receiving a coolant temperature signal of the coolant in the engine transmitted by the coolant sensing component;

[0019] Comparing the coolant temperature corresponding to the coolant temperature signal with the coolant target temperature, and detecting the intake air temperature signal and the pre-combustion chamber temperature signal transmitted by the second temperature sensor and the third temperature sensor respectively based on the comparison result;

[0020] When the intake air temperature and the pre-combustion chamber temperature corresponding to the intake air temperature signal and the pre-combustion chamber temperature signal respectively do not meet the respective set temperatures, the gas pipeline and the pre-combustion chamber are heated respectively by the first heating structure and the second heating structure;

[0021] After the heating is completed, a methanol enrichment injection signal is sent to the methanol enrichment injector, so that the methanol enrichment injector performs multi-stage injection to the pre-combustion chamber.

[0022] Preferably, the step of detecting the intake air temperature signal and the pre-combustion chamber temperature signal respectively transmitted by the second temperature sensor and the third temperature sensor based on the comparison result comprises:

[0023] When the coolant temperature is lower than the coolant target temperature, detecting an intake air temperature signal and a pre-combustion chamber temperature signal transmitted by the second temperature sensor and the third temperature sensor respectively;

[0024] When the coolant temperature is not lower than the coolant target temperature, normal startup is performed using ECU control.

[0025] Preferably, the step of heating the gas pipeline and the pre-combustion chamber respectively by the first heating structure and the second heating structure comprises:

[0026] Based on the pre-combustion chamber shell temperature-intake air temperature MAP, the heating current intensity and heating time matching the first heating structure and the second heating structure are selected respectively, so that the first heating structure and the second heating structure can heat the gas pipeline and the pre-combustion chamber respectively with their matching heating current intensity and heating time.

[0027] Preferably, the step of performing multi-stage injection of the pre-combustion chamber by the methanol enrichment injector comprises:

[0028] Performing a first stage of injection into the pre-combustion chamber at a first equivalence ratio through the methanol enrichment injector;

[0029] A second stage of injection is performed into the pre-combustion chamber at a second equivalence ratio through the methanol enrichment injector, wherein the sum of the first equivalence ratio and the second equivalence ratio is 1.

[0030] Preferably, the method further comprises:

[0031] The engine speed signal is detected. When the speed corresponding to the speed signal reaches a preset idle speed, the intake air heating signal and the pre-combustion chamber heating signal are both set to 0, and the methanol enrichment injector is switched to be controlled by the ECU.

[0032] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A structural principle diagram of a low-temperature cold start auxiliary system for a pure methanol engine provided by a first embodiment of the present invention;

[0034] Figure 2 A signal transmission diagram of a control unit provided for the first embodiment of the present invention;

[0035] Figure 3 A flow chart of a low-temperature cold start assist method for a pure methanol engine is provided for the second embodiment of the present invention.

[0036] Description of main component symbols:

[0037]

[0038]

[0039] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0041] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0043] See also Figure 1 , which is a low-temperature cold start assist system for a pure methanol engine 20 in the first embodiment of the present invention, is suitable for low-altitude cold areas. The system includes a control unit 10, a coolant sensing component, an intake heating control component, a pre-combustion chamber 40 heating control component and a methanol enrichment injector 50.

[0044] Among them: the coolant sensing component, the intake air heating control component, the pre-combustion chamber 40 heating control component and the methanol enrichment injector 50 are all electrically connected to the control unit 10, the coolant sensing component is the first temperature sensor 21, the coolant sensing component is installed in the cooling water jacket of the engine 20, and the coolant sensing component can measure the temperature of the coolant in the engine 20 and send the corresponding coolant temperature signal to the control unit 10, so that the control space can regulate the intake air heating control component and the pre-combustion chamber 40 heating component based on the temperature of the coolant.

[0045] Specifically, the intake air heating control component includes a first heating structure 32 and a second temperature sensor 31 disposed on the gas pipeline 30, and the second temperature sensor 31 measures the intake air temperature of the gas pipeline 30, so that the first heating structure 32 heats the air in the gas pipeline 30 based on the intake air temperature; the pre-combustion chamber 40 heating control component includes a second heating structure 42 and a third temperature sensor 41 disposed on the shell of the pre-combustion chamber 40, and the third temperature sensor 41 measures the temperature of the shell of the pre-combustion chamber 40, so that the second heating structure 42 heats the pre-combustion chamber 40. It should be noted that the control unit 10 can receive the second temperature sensor 31 The intake temperature signal and the pre-combustion chamber 40 temperature signal sent by the third temperature sensor 41 are used to obtain the temperatures of the gas pipeline 30 and the pre-combustion chamber 40 in real time, so that when the temperatures of the gas pipeline 30 and the pre-combustion chamber 40 reach the preset temperature after being heated, the control unit 10 drives the methanol enrichment injector 50 to inject methanol into the pre-combustion chamber 40 in multiple stages at a preset equivalence ratio, so as to improve the problem that due to the small space in the pre-combustion chamber 40, methanol is easy to hit the wall and condense quickly under low temperature environment, resulting in poor fogging effect, resulting in the methanol equivalence ratio in the gas atmosphere in the pre-combustion chamber 40 being too low to meet the ignition conditions, thereby ensuring that the engine 20 can still start quickly and smoothly during cold start.

[0046] It can be understood that the methanol enrichment injector 50 is located in the pre-combustion cavity 43 of the pre-combustion chamber 40, the pre-combustion chamber 40 is located in the cylinder head of the engine 20, the pre-combustion cavity 43 of the pre-combustion chamber 40 is connected to the exhaust end of the gas pipeline 30, the intake air heating control component is located at the intake end 34 of the gas pipeline 30, the intake end 34 of the gas pipeline 30 is installed with a throttle valve 33, and the intake end 34 of the gas pipeline 30, the first heating structure 32, the second temperature sensor 31 and the throttle valve 33 are sequentially arranged along the axial direction of the gas pipeline 30. It should be noted that the composition of the coolant can be any one of cooling water, antifreeze, and additives.

[0047] In the present embodiment, the interior of the shell of the precombustion chamber 40 is hollow to form an installation interlayer, and the second heating structure 42 is located in the installation interlayer, so as not to add a physical heating device in the precombustion cavity 43 of the precombustion chamber 40 and retain the precombustion cavity 43, wherein the number of the second heating structures 42 is two, and two installation positions are provided in the installation interlayer, and the two second heating structures 42 are respectively installed at the two installation positions, and the two installation positions are centrally symmetrically distributed in the installation interlayer. It can be understood that in other embodiments, the number of the second heating structures 42 is four, and accordingly, four installation positions are provided in the installation interlayer, and the four second heating structures 42 are respectively installed at the four installation positions, and the four installation positions are evenly distributed in the installation interlayer at equal angles in the circumferential direction of the precombustion chamber 40.

[0048] In this embodiment, the control unit 10 includes a pre-combustion chamber 40 shell temperature-intake air temperature MAP, and a control parameter table of the heating module is stored in the pre-combustion chamber 40 shell temperature-intake air temperature MAP to ensure that the time required to heat to the target temperature is the same at different initial temperatures, thereby ensuring the smoothness of the starting process.

[0049] It should be noted that the pre-combustion chamber 40 shell temperature-intake air temperature MAP is used to query the heating time and heating current intensity of the first heating structure 32 and the second heating structure 42. It should be noted that in the pre-combustion chamber 40 shell temperature-intake air temperature MAP, different initial temperatures of the pre-combustion chamber 40 shell and the gas pipeline 30 correspond to different heating current intensities. Specifically, in order to ensure the same cold start time under different low temperature environments, a higher heating current intensity is required at a lower ambient temperature.

[0050] It can be understood that the shell temperature of the pre-combustion chamber 40 - the intake air temperature MAP meets the starting performance requirements of the pure methanol engine 20, that is, different calibrations are adopted according to the different environments in which the engine 20 is located. When the first temperature sensor 21, the second temperature sensor 31 and the third temperature sensor 41 respectively transmit corresponding signals to the control unit 10, it will be determined whether to perform starting assistance. If it is determined to perform starting assistance, the initial temperature of the gas pipeline 30 and the initial temperature of the pre-combustion chamber 40 respectively measured by the first temperature sensor 21 and the second temperature sensor 31 are compared with the shell temperature of the pre-combustion chamber 40 - the intake air temperature MAP, so as to select a suitable heating current intensity to ensure the consistency and smoothness of the starting of the engine 20 in different low temperature environments.

[0051] In this embodiment, a speed sensor 22 is installed on the engine 20, and the speed sensor 22 is used to monitor the speed of the engine 20. It can be understood that the speed sensor 22 will transmit the speed signal corresponding to the speed of the engine 20 to the control unit 10. After receiving the speed signal, the control unit 10 will automatically switch the engine 20 from the low-position cold start assist system to the normal idle control stage.

[0052] In this embodiment, the low-temperature cold start assist system of the pure methanol engine 20 also includes a battery 60, and the first temperature sensor 21, the second temperature sensor 31, the third temperature sensor 41, the first heating structure 32 and the second heating structure 42 are all electrically connected to the battery 60 so that the battery 60 can supply power to each temperature sensor and the heating structure.

[0053] It should be noted that the system is suitable for low-altitude cold areas. When the temperature of the coolant in the engine 20 is higher than the set value, the pure methanol engine 20 low-temperature cold start assist system is not used, the precombustion chamber 40 does not need to be heated, a single fuel injection is performed in the precombustion chamber 40, and the engine 20 can be started normally through the control of the control unit 10, reducing the power consumption of the battery 60; when the ambient temperature is low, the control unit 10 automatically uses the pure methanol engine 20 low-temperature cold start assist system to ensure that the engine 20 starts successfully. When the engine 20 starts successfully and enters the idling stage, the first heating structure 32 and the second heating structure 42 are turned off by the control unit 10.

[0054] Specifically, when the driver turns the key to the "ON" position, the control unit 10 detects the Input2 signal of the first temperature sensor 21 and compares it with the set coolant target temperature. When the coolant temperature is lower than the set value, the control unit 10 detects the Input5 signal of the second temperature sensor 31 and the Input3 signal of the third temperature sensor 41, and searches for the heating current intensity and heating time in the pre-stored pre-combustion chamber 40 shell temperature-intake air temperature MAP. The control unit 10 heats the gas pipeline 30 and the pre-combustion chamber 40 through the Output1 signal and the Output2 signal. The control unit 10 controls the methanol enrichment injector 50 through the Output3 signal to enrich the fuel injected into the pre-combustion chamber 40 and perform two-stage injection.

[0055] During the starting process of the engine 20, if the control unit 10 detects that the speed Input6 signal of the engine 20 reaches the idle speed and the temperature of the pre-combustion chamber 40 reaches the temperature set corresponding to the successful ignition state, the control unit 10 sets the intake heating signal Output1 and the pre-combustion chamber 40 heating signal Output2 to 0, and switches the output signal Output3 of the methanol enrichment injector 50 of the pre-combustion chamber 40 to ECU control.

[0056] If the engine 20 is in a hot engine state when starting, the control unit 10 receives the Input2 signal and does not use the low-temperature cold start assist system of the pure methanol engine 20 .

[0057] See also Figure 2 It should be noted that Input 1 of the control unit 10 is the engine 20 start-up signal, Input 2 is the coolant temperature signal, Input 3 is the intake air temperature signal, Input 4 is the pre-combustion chamber 40 temperature signal, Input 5 is the intake air temperature signal, Input 6 is the engine 20 speed signal, Output 1 signal is a signal for controlling the first heating structure 32, Output 2 signal is a signal for the second heating structure 42, and Output 3 signal is a signal for controlling the methanol enrichment injector 50.

[0058] In the specific implementation, the temperature of the coolant in the engine 20 is measured by the coolant sensing component, and the control unit 10 can regulate the intake heating control component and the pre-combustion chamber 40 heating control component based on the coolant temperature, so that the intake heating control component and the pre-combustion chamber 40 heating control component heat the gas pipeline 30 and the pre-combustion chamber 40 respectively. When the temperature of the air in the gas pipeline 30 and the temperature in the pre-combustion chamber 40 reach a certain value, the control unit 10 will drive the methanol enrichment injector 50 to perform multi-stage injection to the pre-combustion chamber 40 at a preset equivalence ratio, so as to quickly increase the temperature in the pre-combustion chamber 40 during cold start, improve the spray effect of methanol under cold start, and increase the proportion of methanol in the mixture, so as to solve the problem that the methanol equivalence ratio of the pure methanol engine 20 is too low and the ignition cannot be successful during cold start, and ensure that the engine 20 can start quickly and smoothly during cold start, and at the same time prevent the phenomenon of excessive methanol droplets accumulating in the pre-combustion chamber 40, thereby preventing the problem of carbon accumulation in the pre-combustion chamber 40 to block the spray hole between the pre-combustion chamber 40 and the main combustion chamber.

[0059] It should be noted that the above implementation process is only for illustrating the feasibility of the present application, but this does not mean that the pure methanol engine 20 low-temperature cold start assist system of the present application has only the above-mentioned single implementation process. On the contrary, as long as the pure methanol engine 20 low-temperature cold start assist system of the present application can be implemented, it can be included in the feasible implementation plan of the present application.

[0060] Please refer to 3, which is a flow chart of a low temperature cold start assisting method for a pure methanol engine 20 in a second embodiment of the present invention. Figure 3 As shown, the method comprises the following steps:

[0061] Step S101, receiving a coolant temperature signal of the coolant in the engine 20 transmitted by a coolant sensing component;

[0062] Step S102, comparing the coolant temperature corresponding to the coolant temperature signal with the coolant target temperature, and detecting the intake air temperature signal and the pre-combustion chamber 40 temperature signal transmitted by the second temperature sensor 31 and the third temperature sensor 41 respectively based on the comparison result;

[0063] Step S103, when the intake air temperature and the pre-combustion chamber 40 temperature corresponding to the intake air temperature signal and the pre-combustion chamber 40 temperature signal respectively do not meet their respective set temperatures, the gas pipeline 30 and the pre-combustion chamber 40 are heated by the first heating structure 32 and the second heating structure 42 respectively;

[0064] Step S104 , after the heating is completed, a methanol enrichment injection signal is sent to the methanol enrichment injector 50 , so that the methanol enrichment injector 50 performs multi-stage injection to the pre-combustion chamber 40 .

[0065] Through the above steps, the coolant sensing component is used to measure the temperature of the coolant in the engine 20, and the control unit 10 can regulate the intake heating control component and the precombustion chamber 40 heating control component based on the coolant temperature, so that the intake heating control component and the precombustion chamber 40 heating control component heat the gas pipeline 30 and the precombustion chamber 40 respectively. When the temperature of the air in the gas pipeline 30 and the temperature in the precombustion chamber 40 reach a certain value, the control unit 10 will drive the methanol enrichment injector 50 to perform multi-stage injection to the precombustion chamber 40 at a preset equivalence ratio, so as to quickly increase the temperature in the precombustion chamber 40 during cold start, improve the spray effect of methanol under cold start, and increase the proportion of methanol in the mixture, so as to solve the problem that the methanol equivalence ratio of the pure methanol engine 20 is too low and the ignition cannot be successful during cold start, and ensure that the engine 20 can start quickly and smoothly during cold start, and at the same time prevent the phenomenon of excessive methanol droplets accumulating in the precombustion chamber 40, thereby preventing the problem of carbon accumulation in the precombustion chamber 40 to block the spray hole between the precombustion chamber 40 and the main combustion chamber.

[0066] In some embodiments, the step of detecting the intake air temperature signal and the pre-combustion chamber 40 temperature signal transmitted by the second temperature sensor 31 and the third temperature sensor 41 respectively based on the comparison result includes:

[0067] When the coolant temperature is lower than the coolant target temperature, detecting the intake air temperature signal and the pre-combustion chamber 40 temperature signal transmitted by the second temperature sensor 31 and the third temperature sensor 41 respectively;

[0068] When the coolant temperature is not lower than the coolant target temperature, normal startup is performed using ECU control.

[0069] In some embodiments, the step of heating the gas pipeline 30 and the pre-combustion chamber 40 respectively by the first heating structure 32 and the second heating structure 42 includes:

[0070] Based on the shell temperature of the pre-combustion chamber 40 - the intake air temperature MAP, the heating current intensity and heating time matching the first heating structure 32 and the second heating structure 42 are selected respectively, so that the first heating structure 32 and the second heating structure 42 both heat the gas pipeline 30 and the pre-combustion chamber 40 respectively with their matching heating current intensity and heating time.

[0071] In some embodiments, the step of the methanol enrichment injector 50 performing multi-stage injection on the pre-combustion chamber 40 includes:

[0072] The methanol enrichment injector 50 performs a first stage injection into the pre-combustion chamber 40 at a first equivalence ratio;

[0073] The methanol enrichment injector 50 performs a second stage of injection into the pre-combustion chamber 40 at a second equivalence ratio, wherein the sum of the first equivalence ratio and the second equivalence ratio is 1.

[0074] In some embodiments, the method further comprises:

[0075] The speed signal of the engine 20 is detected. When the speed corresponding to the speed signal reaches the preset idle speed, the intake air heating signal and the pre-combustion chamber 40 heating signal are both set to 0, and the methanol enrichment injector 50 is switched to the ECU control.

[0076] In a specific embodiment, a low temperature cold start assisting system of a pure methanol engine 20 is used to implement a low temperature cold start assisting method of a pure methanol engine 20, the method comprising:

[0077] 1) The control unit 10 detects the coolant temperature signal in the cooling water jacket of the engine 20. If the coolant temperature corresponding to the coolant temperature signal is lower than the temperature setting value (35°), it is determined that the vehicle is in a cold start state, and the control unit 10 outputs a signal to heat the shell of the pre-combustion chamber 40. When the shell temperature of the pre-combustion chamber 40 reaches the setting value (such as 300°C), the heating is stopped; if the intake air temperature is lower than the setting value (15°C), the control unit 10 outputs a signal to heat the gas passing through the throttle valve 33;

[0078] 2) At the initial start, when the shell temperature of the pre-combustion chamber 40 reaches the set value, the control unit 10 outputs a signal, the electric starter drives the crankshaft to rotate, and the methanol in the pre-combustion chamber 40 is injected in multiple stages at a set equivalent ratio (the first stage is auxiliary injection, accounting for 25% of the total injection amount; the second stage is main injection, accounting for 75% of the total injection amount), and the spark plug ignites according to the set value. At this time, the main combustion chamber intake duct does not spray methanol;

[0079] 3) During the starting process, when the input signal of the third temperature sensor 41 in the housing of the pre-combustion chamber 40 reaches the set range, it is judged that the ignition is successful, methanol is injected into the intake duct of the main combustion chamber, and the methanol in the pre-combustion chamber 40 is switched to single injection, and the starter is shut down at the same time;

[0080] 4) If the start is successful and the engine 20 speed reaches the set speed, the control unit 10 will exit the low-temperature cold start auxiliary control of the pure methanol engine 20, and the vehicle will switch to idle control.

[0081] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0082] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A pure methanol engine low temperature cold start auxiliary system, characterized in that: It comprises a control unit and a coolant induction component, an intake air heating control component, a pre-combustion chamber heating control component and a methanol enrichment injector electrically connected to the control unit; The coolant sensing component is a first temperature sensor, which is used to measure the temperature of the coolant in the engine, so that the control unit can regulate the intake heating control component and the pre-combustion chamber heating control component based on the temperature of the coolant; The intake air heating control assembly comprises a first heating structure and a second temperature sensor provided on the gas pipeline, wherein the intake air temperature of the gas pipeline is measured by the second temperature sensor, so that the first heating structure heats the air in the gas pipeline based on the intake air temperature; The pre-combustion chamber heating control assembly comprises a second heating structure and a third temperature sensor provided on the pre-combustion chamber shell, and the temperature of the pre-combustion chamber shell is measured by the third temperature sensor, so that the second heating structure heats the pre-combustion chamber; The methanol enrichment injector is located in the precombustion cavity of the precombustion chamber, and is used to inject methanol into the precombustion chamber in multiple stages at a preset equivalence ratio according to the temperature of the air in the gas pipeline and the temperature of the precombustion chamber; Wherein, the pre-combustion chamber is located in the cylinder head of the engine, the pre-combustion chamber is connected to the exhaust end of the gas pipeline, and the first temperature sensor is located in the cooling water jacket of the engine.

2. The pure methanol engine low temperature cold start auxiliary system according to claim 1, characterized in that: The control unit includes a pre-combustion chamber housing temperature-intake air temperature MAP, and the pre-combustion chamber housing temperature-intake air temperature MAP is used to query the heating time and heating current intensity of the first heating structure and the second heating structure.

3. The pure methanol engine low temperature cold start auxiliary system according to claim 1, characterized in that: A rotation speed sensor is installed on the engine, and the rotation speed sensor is used to monitor the rotation speed of the engine.

4. The pure methanol engine low temperature cold start assist system according to claim 1, characterized in that: The air inlet end of the air pipeline, the first heating structure and the second temperature sensor are arranged in sequence along the axial direction of the air pipeline.

5. The pure methanol engine low temperature cold start assist system according to claim 1, characterized in that: The pure methanol engine low-temperature cold start auxiliary system also includes a battery, and the coolant sensing component, the intake air heating control component and the pre-combustion chamber heating control component are all electrically connected to the battery.

6. A low temperature cold start assist method for a pure methanol engine, applicable to the low temperature cold start assist system for a pure methanol engine as claimed in any one of claims 1 to 5, characterized in that: The method comprises: receiving a coolant temperature signal of the coolant in the engine transmitted by the coolant sensing component; Comparing the coolant temperature corresponding to the coolant temperature signal with the coolant target temperature, and detecting the intake air temperature signal and the pre-combustion chamber temperature signal transmitted by the second temperature sensor and the third temperature sensor respectively based on the comparison result; When the intake air temperature and the pre-combustion chamber temperature corresponding to the intake air temperature signal and the pre-combustion chamber temperature signal respectively do not meet the respective set temperatures, the gas pipeline and the pre-combustion chamber are heated respectively by the first heating structure and the second heating structure; After the heating is completed, a methanol enrichment injection signal is sent to the methanol enrichment injector, so that the methanol enrichment injector performs multi-stage injection to the pre-combustion chamber.

7. The low temperature cold start assisting method for a pure methanol engine according to claim 6, characterized in that: The step of detecting the intake air temperature signal and the pre-combustion chamber temperature signal transmitted by the second temperature sensor and the third temperature sensor respectively based on the comparison result comprises: When the coolant temperature is lower than the coolant target temperature, detecting an intake air temperature signal and a pre-combustion chamber temperature signal transmitted by the second temperature sensor and the third temperature sensor respectively; When the coolant temperature is not lower than the coolant target temperature, normal startup is performed using ECU control.

8. The low temperature cold start assisting method for a pure methanol engine according to claim 6, characterized in that: The step of heating the gas pipeline and the pre-combustion chamber respectively by the first heating structure and the second heating structure comprises: Based on the pre-combustion chamber shell temperature-intake air temperature MAP, the heating current intensity and heating time matching the first heating structure and the second heating structure are selected respectively, so that the first heating structure and the second heating structure can heat the gas pipeline and the pre-combustion chamber respectively with their matching heating current intensity and heating time.

9. The low temperature cold start assisting method for a pure methanol engine according to claim 6, characterized in that: The step of the methanol enrichment injector performing multi-stage injection on the pre-combustion chamber comprises: Performing a first stage of injection into the pre-combustion chamber at a first equivalence ratio through the methanol enrichment injector; A second stage of injection is performed into the pre-combustion chamber at a second equivalence ratio through the methanol enrichment injector, wherein the sum of the first equivalence ratio and the second equivalence ratio is 1.

10. The low temperature cold start assisting method for a pure methanol engine according to claim 7, characterized in that: The method further comprises: The engine speed signal is detected. When the speed corresponding to the speed signal reaches a preset idle speed, the intake air heating signal and the pre-combustion chamber heating signal are both set to 0, and the methanol enrichment injector is switched to be controlled by the ECU.

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