Fire fighting diesel engine low temperature combustion efficiency improving method

Abstract

The present application relates to a kind of fire diesel engine low temperature combustion efficiency promotion method.Fire diesel engine low temperature combustion efficiency promotion method, starting stage does not need to rely on external point heating equipment, preheating is carried out to intake and fuel respectively using exhaust waste heat and the integrated effect of repeated start, repeated heating under the control of multiple parameters, effectively guarantee the reliability of fast emergency start and emergency start under low temperature environment, through the integrated effect of ultrasonic atomization, multiple parameter collaborative control, effectively solve the problem of poor fuel atomization, mixture is not uniform, combustion is insufficient under low temperature condition, the combustion efficiency under low temperature condition is significantly improved, through the mutual coordination of residual humidity detection, ultrasonic auxiliary water removal unit in shutdown stage, the reliability of next start can be guaranteed.Therefore, the above-mentioned fire diesel engine low temperature combustion efficiency promotion method adapts to the scene demand of fire emergency without external power supply, fast response.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine combustion injection technology, and in particular to a method for improving the low-temperature combustion rate of a fire-fighting diesel engine. Background Technology

[0002] As the core power source of fire emergency systems, the reliability and combustion efficiency of fire-fighting diesel engines directly determine the response speed, operational endurance, and rescue effectiveness of fire-fighting equipment. Especially in low-temperature conditions ranging from -40℃ to 5℃, they must meet the stringent requirements of "immediate start-up, continuous stability, low failure rate, and high-intensity output." However, low-temperature environments have multiple negative impacts on the diesel engine combustion process, creating significant technical bottlenecks: fuel viscosity increases exponentially with decreasing temperature, resulting in poor fuel atomization and excessively large fuel droplet size; excessively low intake air temperature makes it difficult for the cylinder compression final temperature to reach the fuel ignition point, prolonging the ignition delay period; uneven air-fuel mixture leads to incomplete local combustion, causing not only a significant decrease in combustion efficiency and a surge in fuel consumption, but also... Excessive emissions of pollutants such as particulate matter not only increase the difficulty of starting diesel engines and reduce the success rate of starting, but can also cause equipment failure in severe cases, affecting the smooth progress of fire and rescue operations. Summary of the Invention

[0003] Therefore, it is necessary to provide a method for improving the low-temperature combustion efficiency of fire-fighting diesel engines that can solve the core problems of low combustion efficiency, poor scenario adaptability, and difficulty in balancing start-up and stable operation performance under low-temperature conditions in existing technologies.

[0004] A method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine, wherein the diesel engine system has starting modes including a normal starting mode and a low-temperature starting mode, and the method includes the following steps:

[0005] The system provides an exhaust waste heat preheating unit, an ultrasonic-assisted atomization unit, and an ultrasonic-assisted water removal unit. The exhaust waste heat preheating unit is used to recover the exhaust waste heat of the diesel engine and to heat the intake air and fuel of the diesel engine using the exhaust waste heat. The ultrasonic-assisted atomization unit is used to generate high-frequency vibrations to break up fuel droplets. The ultrasonic-assisted water removal unit is used to generate low-frequency ultrasound to remove water from the fuel.

[0006] Collect ambient temperature values ​​and determine whether the ambient temperature values ​​are greater than or equal to a preset ambient temperature threshold.

[0007] If so, the diesel engine system will be controlled to enter normal start mode after receiving the start command;

[0008] If not, the diesel engine system will be controlled to enter the low-temperature start mode after receiving the start command;

[0009] After entering the low-temperature start-up mode, the exhaust waste heat preheating unit is turned on, and the intake air and fuel of the diesel engine are heated at the first preheating temperature respectively.

[0010] Real-time collection of intake air temperature, fuel temperature, cylinder temperature and engine speed of diesel engine;

[0011] Determine whether the following conditions are met simultaneously: the intake air temperature value is ≥ a first preset temperature threshold, and the fuel temperature value is ≥ a second preset temperature threshold.

[0012] If not, return to the steps of heating the intake air and fuel of the diesel engine;

[0013] If so, determine whether the following conditions are met simultaneously: the cylinder temperature value is ≥ the third preset temperature threshold, and the engine speed value is ≥ the first preset speed threshold.

[0014] If not, return to the step of heating the intake air and fuel of the diesel engine, while raising the first preheating temperature to the second preheating temperature and advancing the injection timing by the preset angle.

[0015] If so, or after the diesel engine system enters the normal start mode, determine whether the following conditions are met simultaneously: the engine speed value increases to ≥ the second preset speed threshold within a first preset time period, and the fluctuation range of the combustion pressure value is < the first preset fluctuation range within a first preset number of combustion cycles.

[0016] If not, return to the step of determining whether the ambient temperature value is ≥ the preset ambient temperature threshold;

[0017] If so, the diesel engine is switched to steady-state mode, and the ultrasonic-assisted atomization unit is activated to obtain the average diameter of fuel droplets, atomization uniformity coefficient, and fuel kinematic viscosity.

[0018] Determine whether the following conditions are met simultaneously: the engine speed value is stable within a preset speed range, the average diameter of the fuel droplets is within a preset diameter range, and the atomization uniformity coefficient is ≥ a preset coefficient.

[0019] If not, dynamically adjust the thermostatic valve in the engine cooling system, the ultrasonic frequency of the ultrasonic-assisted atomization unit, and the injection timing, and return to execute the step of determining whether the following conditions are met simultaneously: the engine speed value is stable within the preset speed range, the average diameter of the fuel droplets is within the preset diameter range, and the atomization uniformity coefficient is ≥ the preset coefficient.

[0020] If so, determine whether the following conditions are met simultaneously: the kinematic viscosity of the fuel is within a preset viscosity range, and the fluctuation range of the combustion pressure value within a second preset number of combustion cycles is less than the preset fluctuation range.

[0021] If not, reduce the load rate of the diesel engine to the preset load rate and send a fault warning message.

[0022] If so, after receiving the shutdown command, the engine speed will be reduced to the second preset speed threshold, and the residual humidity value will be checked to see if it is ≤ preset humidity value;

[0023] If not, the ultrasonic-assisted dehumidification unit is activated, and the process returns to the step of detecting whether the residual humidity value is ≤ the preset humidity value.

[0024] If so, then shut down the diesel engine.

[0025] The aforementioned method for improving the low-temperature combustion efficiency of fire-fighting diesel engines eliminates the need for external electric heating equipment during the startup phase. Preheating is achieved solely through exhaust waste heat recovery. This waste heat is used to preheat both the intake air and fuel, and the integrated effect of repeated startup and reheating under multi-parameter coordinated control effectively ensures rapid and reliable emergency startup in low-temperature environments. Through the integrated action of ultrasonic atomization and multi-parameter coordinated control, the problems of poor fuel atomization, uneven air-fuel mixture, and incomplete combustion under low-temperature conditions are effectively solved, balancing energy conservation and environmental protection requirements. This results in a significant improvement in combustion efficiency under low-temperature conditions. During the shutdown phase, the synergistic effect of residual humidity detection and ultrasonic-assisted water removal units ensures the reliability of the next startup. Practical verification shows that using this method enables fire-fighting diesel engines to start rapidly within 30 seconds in extreme low-temperature environments, exhibiting high startup reliability. This is suitable for fire emergency scenarios requiring no external power supply and rapid response, while avoiding the high energy consumption of electric heating, thus improving the energy efficiency of fire-fighting equipment. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine in a preferred embodiment of the present invention.

[0027] Figure 2 for Figure 1 The flowchart of step S8 in the method for improving the low-temperature combustion efficiency of fire-fighting diesel engines is shown.

[0028] Figure 3 for Figure 1 The flowchart of step S12 in the method for improving the low-temperature combustion efficiency of fire-fighting diesel engines is shown.

[0029] Figure 4 for Figure 1The diagram shows a flowchart of step S19 in the method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine. Detailed Implementation

[0030] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] When describing positional relationships, unless otherwise specified, when an element is referred to as being "on" another element, it may be directly on the other element or there may be intermediate elements. It is also understood that when an element is referred to as being "between" two elements, it may be the only one between the two elements, or there may be one or more intermediate elements.

[0033] When using the terms “including,” “having,” and “comprising” as described herein, another component may be added unless explicitly qualifying terms such as “only,” “consisting of,” etc. are used. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0034] Please see Figure 1 The preferred embodiment of the present invention provides a method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine. The starting modes of the diesel engine system include a normal starting mode and a low-temperature starting mode. The method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine includes steps S1 to S20.

[0035] Step S1 provides an exhaust waste heat preheating unit, an ultrasonic-assisted atomization unit, and an ultrasonic-assisted water removal unit.

[0036] The exhaust waste heat preheating unit is used to recover the exhaust waste heat of the diesel engine and use the exhaust waste heat to heat the intake air and fuel of the diesel engine respectively; the ultrasonic-assisted atomization unit is used to generate high-frequency vibration to break up fuel droplets; and the ultrasonic-assisted water removal unit is used to generate low-frequency ultrasonic waves to remove water from the fuel.

[0037] Step S2: Collect the ambient temperature value and determine whether the ambient temperature value is greater than or equal to the preset ambient temperature threshold.

[0038] Specifically, the preset ambient temperature threshold is 5°C. Of course, in some other embodiments, the preset ambient temperature threshold can also be other temperature values ​​above 5°C.

[0039] Step S3: If yes, then after receiving the start command, control the diesel engine system to enter the normal start mode.

[0040] It should be noted that the normal start mode is a diesel engine start mode that can be started directly by ignition without preheating, and is suitable for fire emergency scenarios where the ambient temperature is above the preset ambient temperature threshold.

[0041] Step S4: If not, control the diesel engine system to enter the low-temperature start mode after receiving the start command.

[0042] It should be noted that the low-temperature start-up mode is a start-up mode that requires preheating before ignition and is suitable for fire emergency scenarios in extreme low-temperature environments.

[0043] Step S5: After entering the low-temperature start-up mode, the exhaust waste heat preheating unit is turned on, and the intake air and fuel of the diesel engine are heated at the first preheating temperature.

[0044] In step S5, the exhaust waste heat preheating unit recovers the exhaust waste heat generated during the initial start-up of the diesel engine and uses this exhaust waste heat to heat the intake air and fuel of the diesel engine, so as to reduce start-up energy consumption while ensuring rapid start-up in low-temperature environments.

[0045] Step S6: Real-time acquisition of the intake air temperature, fuel temperature, cylinder temperature and engine speed of the diesel engine.

[0046] Step S7: Determine whether the following conditions are met simultaneously: intake air temperature value ≥ first preset temperature threshold, fuel temperature value ≥ second preset temperature threshold.

[0047] Specifically, the first preset temperature threshold is -10℃, and the second preset temperature threshold is 3℃. Of course, in some other embodiments, the first preset temperature threshold may also be other temperatures between -8℃ and -11℃, and the second preset temperature threshold may also be other temperature values ​​between 2℃ and 5℃.

[0048] Specifically, it is determined whether the following conditions are met simultaneously: the intake air temperature is greater than or equal to a first preset temperature threshold, the fuel temperature is greater than or equal to a second preset temperature threshold, and the intake air temperature and fuel temperature do not fluctuate within a sixth preset time period, in order to improve the reliability of successful preheating. More specifically, the sixth preset time is 3 seconds. Of course, in some other embodiments, the sixth preset time can also be 2 seconds, 4 seconds, or other preset times.

[0049] Step S8: If not, return to step S5.

[0050] If either the intake air temperature or the fuel temperature does not meet the conditions in step S7, it indicates that preheating has failed, and the process must return to step S5 to continue heating the intake air and fuel of the diesel engine.

[0051] Step S9: If yes, determine whether the following conditions are met simultaneously: cylinder temperature ≥ third preset temperature threshold, engine speed ≥ first preset speed threshold. If yes, that is, intake air temperature ≥ first preset temperature threshold and fuel temperature ≥ second preset temperature threshold, then the preheating is qualified.

[0052] Specifically, the third preheating temperature threshold is 220°C, and the first preset rotation speed threshold is 200 r / min. Of course, in some other embodiments, the third preheating temperature threshold can also be other temperature values ​​between 200°C and 240°C, and the first preset rotation speed threshold can also be other rotation speed values ​​between 180 r / min and 250 r / min.

[0053] Step S10: If not, return to the step of heating the intake air and fuel of the diesel engine, while raising the first preheating temperature to the second preheating temperature and advancing the injection timing by a preset angle.

[0054] Step S11: If yes, or after the diesel engine system enters normal start mode, determine whether the following conditions are met simultaneously: the engine speed increases by ≥ the second preset speed threshold within a first preset time period, and the fluctuation range of the combustion pressure value is < the first preset fluctuation range within a first preset number of combustion cycles. Step S11 is executed after steps S3 and S10 to determine whether the engine has started successfully.

[0055] Specifically, the first preset time is 10 seconds, the second preset speed threshold is 80% of the engine's rated speed, the first preset quantity is 3, and the first preset fluctuation range is 8%. Of course, in some other embodiments, the first preset time can also be 9 seconds, 11 seconds, or other times, the second preset speed threshold can also be 79%, 83%, or other proportions of the engine's rated speed, or even other preset specific speed values, such as 1200 r / min, 1250 r / min, the first preset quantity can also be 2, 4, or other quantities, and the first preset fluctuation range can also be 9%, 7%, or other fluctuation ranges.

[0056] If not, proceed to step S12. If not, return to step S2. If not, it indicates that the startup failed, and return to repeat steps S2 to S11 to restart.

[0057] Step S13: If yes, control the diesel engine system to switch to steady-state mode, and simultaneously start the ultrasonic-assisted atomization unit to obtain the average diameter of fuel droplets, atomization uniformity coefficient, and fuel kinematic viscosity.

[0058] If so, it means the start-up was successful. At this point, the diesel engine switches to steady-state mode and enters a stable operating phase.

[0059] Step S14: Determine whether the following conditions are met simultaneously: the engine speed is stable within the preset speed range, the average diameter of fuel droplets is within the preset diameter range, and the atomization uniformity coefficient is ≥ the preset coefficient.

[0060] Step S15: If not, dynamically adjust the thermostat valve in the engine cooling system, the ultrasonic frequency of the ultrasonic-assisted atomizing unit, and the injection timing, and return to step S14.

[0061] Specifically, a fuzzy PID fusion algorithm is used to dynamically adjust the thermostatic valve, ultrasonic frequency of the ultrasonic-assisted atomizing unit, and fuel injection timing in the engine cooling system. This enhances the adaptability of the adjustment of the above three core parameters during steady-state operation, significantly improves anti-interference capability, enhances operational reliability, optimizes dynamic response, and balances the speed and stability of adaptive adjustment.

[0062] Specifically, the preset rotational speed range is ±75 r / min, the preset diameter range is 18 μm to 22 μm, and the preset coefficient is 0.85. Of course, in some other embodiments, the preset rotational speed range can also be other parameter ranges such as ±50 r / min, the preset diameter range can also be other reasonable diameter ranges such as ≤18 μm or >22 μm, and the preset coefficient can also be other coefficients such as 0.8.

[0063] In this process, the ultrasonic waves generated by the ultrasonic-assisted atomization unit induce a "cavitation effect" within the fuel, where tiny bubbles rapidly form, expand, and violently break apart. The resulting localized shock waves further aid in fuel breakup, reducing fuel droplet diameter and improving atomization uniformity. In step S15, the fuel atomization effect is adjusted by regulating the ultrasonic frequency of the ultrasonic blocking atomization unit.

[0064] By executing steps S13 to S15, during the steady-state operation phase, the three core parameters of fuel droplet average diameter, atomization uniformity coefficient, and fuel kinematic viscosity are monitored in real time, and these three core parameters are dynamically and adaptively adjusted to ensure uniform combustion and reduce unburned hydrocarbon emissions and fuel consumption.

[0065] Step S16: If yes, determine whether the following conditions are met simultaneously: the kinematic viscosity of the fuel is within a preset viscosity range, and the fluctuation range of the combustion pressure value within a second preset number of combustion cycles is less than the second preset fluctuation range.

[0066] Specifically, the preset viscosity range is 2.5 mm. 2 / s to 8.0mm 2 / s, the second preset quantity is 3, and the second preset fluctuation range is 8%. Of course, in some other embodiments, the second preset quantity can also be 2, 4, or other quantities, and the second preset fluctuation range can also be 9%, 7%, or other fluctuation ranges.

[0067] Step S17: If not, reduce the load rate of the diesel engine to a preset load rate and issue a fault warning message. Specifically, the preset load rate is 50%. Of course, in some other embodiments, the preset load rate can also be 55%, 48%, or other load rates.

[0068] By executing steps S16 and S17, the system can cope with the sudden load change. When the load changes suddenly, the system will actively reduce the load rate of the diesel engine and issue a fault warning to remind the staff to troubleshoot the fault in time. After troubleshooting the fault, the system will shut down the engine.

[0069] Step S18: If yes, after receiving the shutdown command, reduce the engine speed to a second preset speed threshold and check whether the residual humidity value is ≤ a preset humidity value. Specifically, the second speed threshold is 500 r / min, and the preset humidity value is 10%. Of course, in some other embodiments, the second speed threshold can also be 500 r / min or other speed values, and the preset humidity value can also be 12% or other humidity values.

[0070] Step S19: If not, start the ultrasonic-assisted dehumidification unit and return to the execution check if the residual humidity value is ≤ the preset humidity value.

[0071] Step S20: If yes, then control the diesel engine to stop.

[0072] By executing steps S17 to S20, a normal shutdown is performed after the diesel engine has reached a normal steady-state operating state. By executing step S18, residual moisture in the pipeline is reduced, preventing pipeline freezing and blockage in low-temperature environments, reducing potential equipment failure risks, and improving the reliability of the next startup.

[0073] Among them, steps S1 to S13 are the control flow for the diesel engine start-up stage, steps S13 to S17 are the control flow for the diesel engine steady-state operation stage, and steps S18 to S20 are the control flow for the diesel engine shutdown stage.

[0074] Specifically, steps S2 and S11 to S13 constitute the normal start-up process of a diesel engine under normal temperature conditions (the ambient temperature is greater than a preset ambient temperature threshold). Steps S2 and S4 to S13 constitute the low-temperature rapid start-up process of a diesel engine under low-temperature conditions (the ambient temperature is less than or equal to a preset ambient temperature threshold).

[0075] By executing steps S1 to S13, the start-up phase does not rely on external electric heating equipment. Preheating is achieved solely through exhaust waste heat recovery. Practical verification has shown that by adopting the above method, the fire-fighting diesel engine can start rapidly within 30 seconds in extreme low-temperature environments, exhibiting high start-up reliability. This method is suitable for fire emergency scenarios requiring no external power supply and rapid response, while avoiding the high energy consumption problem of electric heating and improving the energy efficiency of fire-fighting equipment.

[0076] Thus, the aforementioned method for improving the low-temperature combustion efficiency of fire-fighting diesel engines employs an integrated technical solution combining exhaust waste heat preheating, ultrasonic atomization, and multi-parameter collaborative control. This optimizes the low-temperature combustion process through preheating, atomization, and regulation, addressing the core issues of low combustion efficiency, poor scenario adaptability, and difficulty in balancing start-up and stable operation performance in existing fire-fighting diesel engines under low-temperature conditions. During the start-up phase, this method eliminates the need for external electric heating equipment, relying solely on exhaust waste heat recovery for preheating. The integrated function of preheating both intake air and fuel using exhaust waste heat, along with repeated start-up and reheating under multi-parameter collaborative control, effectively ensures rapid and reliable emergency start-up in low-temperature environments. The integrated function of ultrasonic atomization and multi-parameter collaborative control effectively solves the problems of poor fuel atomization, uneven air-fuel mixture, and incomplete combustion under low-temperature conditions, balancing energy conservation and environmental protection requirements. This significantly improves combustion efficiency under low-temperature conditions. During shutdown, the synergistic effect of residual humidity detection and ultrasonic-assisted water removal units ensures the reliability of the next start-up.

[0077] In some embodiments, the exhaust waste heat preheating unit includes an exhaust waste heat exchanger, an intake heat exchanger, and a fuel heat exchanger. The exhaust waste heat exchanger has an exhaust passage and a first heat transfer medium passage. Both ends of the exhaust passage are connected to the exhaust pipe of the diesel engine.

[0078] The intake heat exchanger is mounted on the intake manifold of the diesel engine and has a second heat transfer medium passage. The fuel heat exchanger has an inlet fuel passage and a third heat transfer medium passage. The two ends of the inlet fuel passage are connected to the fuel filter and the fuel injection pump, respectively.

[0079] One end of the first heat-conducting medium channel is connected to one end of both the second and third heat-conducting medium channels. The other end of the second heat-conducting medium channel is connected to the other ends of both the second and third heat-conducting medium channels.

[0080] Heat transfer media such as heat transfer oil are added to the first, second, and third heat transfer media channels to utilize the flow and heat exchange of the heat transfer media to recover the exhaust waste heat discharged from the diesel engine in the exhaust waste heat exchanger. The recovered heat energy is then transferred to the intake air heat exchanger and the fuel heat exchanger to heat the intake air and fuel of the diesel engine, respectively.

[0081] Furthermore, in some embodiments, the intake heat exchanger includes an inner intake tube and a first heat exchange outer tube nested on the inner intake tube. The outer wall of the inner intake tube and the inner wall of the first heat exchange outer tube are spaced apart to form a first heat exchange medium channel. Both ends of the inner intake tube are connected to an intake manifold.

[0082] Thus, the intake heat exchanger has a nested inner and outer tube structure. The inner intake tube is connected to the intake manifold and is used to transport the intake air. The first outer heat exchange tube is used to circulate the heat transfer medium, so as to reduce the volume of the intake heat exchanger while ensuring high intake preheating efficiency.

[0083] Furthermore, in some embodiments, the fuel heat exchanger includes an inner inlet tube serving as an oil inlet channel and a second outer heat exchange tube spirally wound around the inner inlet tube and serving as a third heat exchange medium channel.

[0084] Thus, the inner fuel pipe is connected to the fuel circuit of the diesel engine to transport fuel, and the second heat exchange outer pipe is used to circulate the heat transfer medium. The second heat exchange outer pipe is arranged on the inner fuel pipe in a spiral winding manner to increase the heat exchange area, ensure uniform heating of the fuel, and reduce the difficulty of atomization.

[0085] In some embodiments, the fuel injector has multiple streamlined nozzles. These streamlined nozzles feature a biomimetic streamlined design. The injection angles of any two adjacent streamlined nozzles are staggered. This biomimetic streamlined design endows the nozzles with flow-guiding characteristics, and the staggered angles of any two adjacent streamlined nozzles create a multi-layered turbulent mixing region, enhancing the collision and mixing effect between fuel droplets and intake air.

[0086] Furthermore, in some embodiments, the inner wall of the streamlined nozzle is formed with streamlined micropore texture or wavy microfilm texture to reduce the adhesion rate of fuel on the nozzle wall, reduce the probability of fuel residue condensation clogging the streamlined nozzle at low temperatures, and thus improve the reliability of the next start of the diesel engine.

[0087] In some embodiments, a manual adjustment switch is also integrated into the diesel engine control panel. The manual adjustment switch receives interactive operations to set the preheating temperature of the exhaust waste heat preheating unit, the ultrasonic frequency of the ultrasonic-assisted atomization unit, and the fuel injection timing. The manual adjustment switch is a switch in a broad sense, and can be a button, key, knob, push-button switch, etc. The manual adjustment switch allows operators to manually set the intake air temperature, ultrasonic frequency of the ultrasonic-assisted atomization unit, and fuel injection timing when the diesel engine system malfunctions, ensuring that the fire-fighting diesel engine can still operate normally in emergency scenarios and meet the reliability requirements of fire rescue.

[0088] Furthermore, in some embodiments, the engine control unit includes an automatic control mode and an emergency manual mode. In the emergency manual mode, the engine control unit receives preset control commands generated by the manual adjustment switch based on interactive operations. Specifically, the judgment and control portions in steps S2 to S20 are performed using the engine control unit.

[0089] Step S7 is to determine whether the following conditions are met simultaneously: during the second preset heating time, the intake air temperature value is ≥ the first preset temperature threshold, and the fuel temperature value is ≥ the second preset temperature threshold. Specifically, the second preset time is 30 seconds. Of course, in some other embodiments, the second preset time can also be 20 seconds, 32 seconds, or other times.

[0090] Please refer to the following: Figure 2 Step S8 includes steps S8-1 to S8-4.

[0091] Step S8-1: If not, then a preheating fault warning message is issued, and the exhaust waste heat preheating unit is used to continue heating the intake air and fuel of the diesel engine for a third preset time. Specifically, the third preset time is 5 seconds. Of course, in some other embodiments, the third preset time can also be 4 seconds, 6 seconds, or other times.

[0092] Step S8-2: Determine whether the following conditions are met simultaneously: intake air temperature value ≥ first preset temperature threshold, fuel temperature value ≥ second preset temperature threshold.

[0093] Step S8-4: If not, switch the engine control unit from automatic control mode to emergency manual mode, and use the engine control unit to receive the control command generated by the manual adjustment switch according to the interactive operation to manually set the preheating temperature of the exhaust waste heat preheating unit, and control the exhaust waste heat preheating unit to continue to heat the intake air and fuel of the diesel engine.

[0094] If so, proceed to step S8-3. If yes, proceed to step S9.

[0095] Thus, by executing steps S7, S8-1 to S8-4, the intake air and fuel of the diesel engine are first preheated normally. If the preheating is successful, the process proceeds directly to step S9. If the preheating is not up to standard after the second preset heating time, a preheating fault warning is issued to remind the operator. At the same time, the preheating temperature of the exhaust waste heat preheating unit is increased, and the heating time of the intake air and fuel of the diesel engine is extended by the third preset time. The process is then judged whether the preheating is up to standard. If it is up to standard, the process proceeds directly to step S9. If the preheating is not up to standard, the control mode of the engine control unit is automatically switched from automatic control mode to emergency manual mode. This allows the operator to manually adjust and control the preheating temperature and preheating time of the exhaust waste heat preheating unit using a manual adjustment switch to ensure reliable preheating of the intake air and fuel of the diesel engine in low-temperature environments.

[0096] Please refer to the following: Figure 3 In some embodiments, step S12 includes steps S12-1 to S12-2.

[0097] If not, return to the step of determining whether the ambient temperature value is ≥ the preset ambient temperature threshold, and obtain the number of times the step has been returned.

[0098] In step S12-2, if the number of times the execution step is returned is greater than a preset number, a start-up fault warning message is issued, and the engine control unit is locked. Specifically, the preset number is 2. Of course, in some other embodiments, the preset number can also be 3 or other numbers.

[0099] If step S12-1 is executed, it indicates that the start has failed and a restart is required. If the start still fails after a preset number of restarts, a start fault warning is triggered, and the engine control unit is locked to stop the start action. This method of repeated start-ups improves start reliability, and the method of triggering a start fault warning after a preset number of restarts ensures the safe use of emergency fire-fighting equipment.

[0100] Please refer to the following: Figure 4 In some embodiments, step S19 includes steps S19-1 to S19-2.

[0101] Step S19-1: If not, control the fuel injection pump to stop working, and when the engine speed drops below the third speed threshold, start the exhaust waste heat preheating unit to work for a fourth preset time, and detect whether the residual humidity value is ≤ the preset humidity value. Specifically, the third speed threshold is 500 r / min, and the fourth preset time is 10 min to 15 min. Of course, in some other embodiments, the third speed threshold can also be other speed values ​​such as 450 r / min.

[0102] Step S19-2: If not, control the exhaust waste heat preheating unit to continue operating for the fifth preset time, and start the ultrasonic-assisted dehumidification unit until the residual humidity value is ≤ the preset humidity value. Specifically, the fifth preset time is 5 minutes. Of course, in some other embodiments, the fifth preset time can also be a preset time of 4 minutes, 6 minutes, etc.

[0103] By executing steps S19-1 to S19-2, if the residual humidity value is detected to be greater than the preset humidity threshold during the shutdown phase, it indicates that there is too much residual moisture and high humidity in the diesel engine pipeline. After stopping fuel injection, the exhaust waste heat preheating unit is used to continue heating the intake pipeline and fuel pipeline of the diesel engine for a fourth preset time. If the residual humidity value is less than or equal to the preset humidity value, it means that the drying is up to standard. Otherwise, it means that the drying is not up to standard. At this time, it is necessary to control the exhaust waste heat preheating unit to extend the heating time to a fifth preset time and start the ultrasonic-assisted water removal unit. While continuing to dry, the ultrasonic waves emitted by the ultrasonic-assisted water removal unit are used to assist in water removal until the drying is up to standard. This ensures that the diesel engine pipeline is relatively dry after shutdown, improves the drying reliability, avoids ice blockage in the diesel engine pipeline under low temperature conditions, further reduces the risk of equipment failure, and improves the reliability of the diesel engine's next start.

[0104] In some embodiments, steps S21 to S23 are further included after step S20.

[0105] Step S21 also provides an emergency electric heat tracing unit.

[0106] Step S22: Real-time acquisition of intake air temperature and fuel temperature values.

[0107] Step S23: If the intake air temperature and / or fuel temperature drop below the fourth preset temperature threshold, the emergency electric heating unit is activated to heat and insulate the engine's fuel lines and intake manifold. The fourth preset temperature threshold is set such that the intake manifold and fuel lines do not freeze or crack when the diesel engine is stopped. Specifically, -1℃ ≤ the fourth preset temperature threshold is ≤2℃. More specifically, the fourth preset temperature threshold is any temperature value within the range of 0℃ to 1℃. Preferably, the fourth preset temperature threshold is 0℃.

[0108] By executing steps S21 to S23, problems such as pipe icing, blockage, and cracking caused by a sudden drop in temperature inside the diesel engine pipes are addressed after the diesel engine stops. Specifically, the temperature inside the diesel engine pipes is monitored in real time after the diesel engine is completely stopped, and the emergency electric heat tracing unit is activated when the temperature drops below the fourth preset temperature threshold to achieve emergency insulation of the diesel engine pipes. This ensures that the diesel engine pipes can remain stable above the fourth preset temperature threshold while the engine is stopped, thereby reducing the risk of equipment failure and improving the safety and reliability of the next startup.

[0109] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine, characterized in that, The starting modes of the diesel engine system include normal starting mode and cold start mode, and the method includes the following steps: The system provides an exhaust waste heat preheating unit, an ultrasonic-assisted atomization unit, and an ultrasonic-assisted water removal unit; the exhaust waste heat preheating unit is used to recover the exhaust waste heat of the diesel engine and use the exhaust waste heat to heat the intake air and fuel of the diesel engine respectively; the ultrasonic-assisted atomization unit is used to generate high-frequency vibration to break up fuel droplets. The ultrasonic-assisted water removal unit is used to generate low-frequency ultrasonic waves to remove water from fuel. Collect ambient temperature values ​​and determine whether the ambient temperature values ​​are greater than or equal to a preset ambient temperature threshold. If so, the diesel engine system will be controlled to enter normal start mode after receiving the start command; If not, the diesel engine system will be controlled to enter the low-temperature start mode after receiving the start command; After entering the low-temperature start-up mode, the exhaust waste heat preheating unit is turned on, and the intake air and fuel of the diesel engine are heated at the first preheating temperature respectively. Real-time collection of intake air temperature, fuel temperature, cylinder temperature and engine speed of diesel engine; Determine whether the following conditions are met simultaneously: the intake air temperature value is ≥ a first preset temperature threshold, and the fuel temperature value is ≥ a second preset temperature threshold. If not, return to the steps of heating the intake air and fuel of the diesel engine; If so, determine whether the following conditions are met simultaneously: the cylinder temperature value is ≥ the third preset temperature threshold, and the engine speed value is ≥ the first preset speed threshold. If not, return to the step of heating the intake air and fuel of the diesel engine, while raising the first preheating temperature to the second preheating temperature and advancing the injection timing by the preset angle. If so, or after the diesel engine system enters the normal start mode, determine whether the following conditions are met simultaneously: the engine speed value increases to ≥ the second preset speed threshold within a first preset time period, and the fluctuation range of the combustion pressure value is < the first preset fluctuation range within a first preset number of combustion cycles. If not, return to the step of determining whether the ambient temperature value is ≥ the preset ambient temperature threshold; If so, the diesel engine is switched to steady-state mode, and the ultrasonic-assisted atomization unit is activated to obtain the average diameter of fuel droplets, atomization uniformity coefficient, and fuel kinematic viscosity. Determine whether the following conditions are met simultaneously: the engine speed value is stable within a preset speed range, the average diameter of the fuel droplets is within a preset diameter range, and the atomization uniformity coefficient is ≥ a preset coefficient. If not, dynamically adjust the thermostatic valve in the engine cooling system, the ultrasonic frequency of the ultrasonic-assisted atomization unit, and the injection timing, and return to execute the step of determining whether the following conditions are met simultaneously: the engine speed value is stable within the preset speed range, the average diameter of the fuel droplets is within the preset diameter range, and the atomization uniformity coefficient is ≥ the preset coefficient. If so, determine whether the following conditions are met simultaneously: the kinematic viscosity of the fuel is within a preset viscosity range, and the fluctuation range of the combustion pressure value within a second preset number of combustion cycles is less than the preset fluctuation range. If not, reduce the load rate of the diesel engine to the preset load rate and send a fault warning message. If so, after receiving the shutdown command, the engine speed will be reduced to the second preset speed threshold, and the residual humidity value will be checked to see if it is ≤ preset humidity value; If not, the ultrasonic-assisted dehumidification unit is activated, and the process returns to the step of detecting whether the residual humidity value is ≤ the preset humidity value. If so, then shut down the diesel engine.

2. The method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine according to claim 1, characterized in that, The exhaust waste heat preheating unit includes an exhaust waste heat exchanger, an intake heat exchanger, and a fuel heat exchanger; the exhaust waste heat exchanger has an exhaust passage and a first heat transfer medium passage; both ends of the exhaust passage are connected to the exhaust pipe of the diesel engine. The intake heat exchanger is installed on the intake manifold of the diesel engine and has a second heat transfer medium passage. The fuel heat exchanger has an oil inlet channel and a third heat transfer medium channel; The two ends of the oil inlet channel are respectively connected to the fuel filter and the fuel injection pump; One end of the first heat-conducting medium channel is connected to one end of the second heat-conducting medium channel and one end of the third heat-conducting medium channel, respectively; the other end of the second heat-conducting medium channel is connected to the other end of the second heat-conducting medium channel and the third heat-conducting medium channel, respectively.

3. The method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine according to claim 2, characterized in that, The intake heat exchanger includes an inner intake pipe and a first outer heat exchange pipe nested on the inner intake pipe; the outer wall of the inner intake pipe and the inner wall of the first outer heat exchange pipe are spaced apart to form a first heat exchange medium channel; both ends of the inner intake pipe are connected to the intake manifold; and / or The fuel heat exchanger includes an inner inlet tube that serves as the oil inlet channel and a second outer heat exchange tube that is spirally wound around the inner inlet tube and serves as the third heat exchange medium channel.

4. The method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine according to claim 1, characterized in that, The injector has multiple streamlined nozzles; the injection angles of any two adjacent streamlined nozzles are staggered.

5. The method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine according to claim 1, characterized in that, The diesel engine control panel also integrates a manual adjustment switch; the manual adjustment switch is used to receive interactive operations to set the preheating temperature of the exhaust waste heat preheating unit, the ultrasonic frequency of the ultrasonic-assisted atomization unit, and the fuel injection timing.

6. The method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine according to claim 5, characterized in that, The engine control unit includes an automatic control mode and an emergency manual mode; the engine control unit is used in the emergency manual mode to receive preset control commands generated by the manual adjustment switch based on interactive operation; The step of determining whether the following conditions are met simultaneously, namely, the intake air temperature value ≥ the first preset temperature threshold and the fuel temperature value ≥ the second preset temperature threshold, is as follows: determine whether the following conditions are met simultaneously, namely, during the second preset heating time, the intake air temperature value ≥ the first preset temperature threshold and the fuel temperature value ≥ the second preset temperature threshold. If not, return to the steps of heating the intake air and fuel of the diesel engine, including: If not, the system will issue a preheating fault warning and use the exhaust waste heat preheating unit to continue heating the intake air and fuel of the diesel engine for a third preset time. Determine whether the following conditions are met simultaneously: the intake air temperature value is ≥ a first preset temperature threshold, and the fuel temperature value is ≥ a second preset temperature threshold. If not, the engine control unit is switched from automatic control mode to emergency manual mode, and the engine control unit receives the control command generated by the manual adjustment switch according to the interactive operation to manually set the preheating temperature of the exhaust waste heat preheating unit, and controls the exhaust waste heat preheating unit to continue to heat the intake air and fuel of the diesel engine. If so, proceed to the step of determining whether the following conditions are met simultaneously: cylinder temperature value ≥ third preset temperature threshold, engine speed value ≥ first preset speed threshold.

7. The method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine according to claim 1, characterized in that, The step of determining whether the following conditions are simultaneously met, namely, the intake air temperature value ≥ a first preset temperature threshold and the fuel temperature value ≥ a second preset temperature threshold, is as follows: Determine whether the following conditions are simultaneously met: the intake air temperature value ≥ a first preset temperature threshold, the fuel temperature value ≥ a second preset temperature threshold, and the intake air temperature value and the fuel temperature value do not fluctuate within a sixth preset time period; and / or The steps for dynamically adjusting the ultrasonic frequency and injection timing of the thermostat valve and ultrasonic-assisted atomizing unit in the engine cooling system are as follows: The fuzzy PID fusion algorithm is used to dynamically adjust the ultrasonic frequency and injection timing of the thermostat valve and ultrasonic-assisted atomizing unit in the engine cooling system.

8. The method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine according to claim 1, characterized in that, If not, return to the step of determining whether the ambient temperature value is ≥ a preset ambient temperature threshold, including: If not, return to the step of determining whether the ambient temperature value is ≥ the preset ambient temperature threshold, and obtain the number of times the step has been returned to be executed; If the number of times the execution steps are returned exceeds the preset number, the control will issue a start-up fault warning and lock the engine control unit.

9. The method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine according to claim 1, characterized in that, If not, the ultrasonic-assisted dehumidification unit is activated until the residual humidity value is less than or equal to the preset humidity value, including the following steps: If not, the fuel injection pump will stop working, and when the engine speed drops below the third speed threshold, the exhaust waste heat preheating unit will start working for the fourth preset time, and the residual humidity value will be checked to see if it is ≤ the preset humidity value. If not, the exhaust waste heat preheating unit will continue to work for a fifth preset time, and the ultrasonic-assisted dehumidification unit will be started until the residual humidity value is less than or equal to the preset humidity value.

10. The method for improving the low-temperature combustion efficiency of a fire-fighting diesel engine according to claim 1, characterized in that, Following the steps of controlling the diesel engine shutdown, the following steps are also included: An emergency electric heat tracing unit is also provided; The intake air temperature and fuel temperature values ​​are collected in real time. If the intake air temperature and / or the fuel temperature drop below the fourth preset temperature threshold, the emergency electric heating unit is activated to heat and insulate the engine's fuel lines and intake manifold, respectively.

Images