Control method of compression ignition type hydrogen-diesel mixed combustion single-cylinder engine system

Abstract

The invention discloses a control method of a compression ignition type hydrogen-diesel mixed combustion single-cylinder engine system, and belongs to the technical field of compression ignition type engines. The engine system comprises a cylinder cover matched with a cylinder sleeve of an engine, an air inlet system, a diesel oil supply system, a hydrogen supply system, a cooling system and an electric control system. A high-pressure air storage tank of the air inlet system is connected with an air inlet channel in the cylinder cover through a pipeline. A hydrogen spraying device of the hydrogen supply system is arranged on the cylinder cover and communicated with the combustion chamber, and a hydrogen spraying hole of the hydrogen spraying device is communicated with an inner cavity of the hydrogen spraying device through a spiral air channel arranged in the air outlet end of the hydrogen spraying device; a water spraying valve of the water spraying system is communicated with an air inlet pipeline of the air inlet system. And the cooling system is a forced circulation cooling system. The injection timing and pulse width of diesel oil, hydrogen and water, the air inlet pressure and flow, the optimal cooling temperature of a cooling medium and the like are controlled on line through an electric control system. The hydrogen replacement rate can be increased, knocking can be reduced, and the engine efficiency can be improved.

Description

Technical Field

[0001] This invention relates to a control method for a compression ignition hydrogen-diesel hybrid single-cylinder engine system, belonging to the field of compression ignition engine technology. Background Technology

[0002] With the increasing scarcity of non-renewable resources, hydrogen fuel, as a clean energy source, is being widely used in the field of internal combustion engines.

[0003] Existing single-cylinder diesel engines mostly use pure diesel fuel, resulting in high fuel consumption, low efficiency, poor economy, high particulate emissions causing environmental pollution, untimely fuel combustion, high smoke during acceleration, and slow torque build-up. Engines using hydrogen-diesel fuel can partially improve these problems, increasing combustion efficiency, reducing fuel consumption, and lowering particulate emissions and total sulfur oxides. However, while hydrogen fuel has advantages such as high calorific value, high combustion efficiency, and clean emissions, its extremely fast combustion speed, combined with air in the combustion chamber, easily leads to a rapid pressure increase, causing knocking. Knocking not only affects engine reliability and lifespan but may also increase emissions and fuel consumption. Furthermore, existing hydrogen-diesel single-cylinder engines also suffer from the following problems: 1. Low hydrogen substitution rate at high power, resulting in high fuel consumption; 2. Insufficient mixing of hydrogen with air and diesel fuel in the combustion chamber, affecting engine efficiency. The secondary technical problem this invention aims to solve is that existing hydrogen-diesel single-cylinder engines are prone to hydrogen leakage at the hydrogen injector, which can easily lead to flame propagation between the hydrogen injector and the cylinder head. Summary of the Invention

[0004] To address the aforementioned deficiencies in the existing technology, this invention provides a control method for a compression ignition hydrogen-diesel hybrid single-cylinder engine system that can improve hydrogen substitution rate, reduce knocking, and enhance engine efficiency.

[0005] This invention is achieved through the following technical solution: a control method for a compression-ignition hydrogen-diesel hybrid single-cylinder engine system. The compression-ignition hydrogen-diesel hybrid single-cylinder engine system includes a cylinder head that mates with the engine's cylinder liner, an air intake system, a diesel supply system, a hydrogen supply system, a cooling system, and an electronic control system. The air intake system includes a high-pressure gas tank connected to an air intake passage on the cylinder head via an air intake pipe. An air pressure regulating valve is installed on the air intake pipe. The hydrogen supply system includes a hydrogen tank, a hydrogen pressure regulating valve, a hydrogen flow valve, a flame arrester, and a hydrogen injector connected sequentially via a hydrogen intake pipe. The hydrogen injector is mounted on the cylinder head and communicates with the combustion chamber. The hydrogen injector is tilted, and its tilt direction and angle are aligned with the air intake passage. The hydrogen injector has a smaller outlet diameter than its inlet diameter, and multiple hydrogen injection holes are provided at the outlet end. These holes are connected to the inner cavity of the hydrogen injector through a spiral air passage inside the outlet end. The system also includes a water injection system, comprising a water tank, a high-pressure water pump, and a water injection valve connected sequentially via a water supply pipeline. The water injection valve is connected to the air intake pipeline of the air intake system. The cooling system is a forced circulation cooling system, equipped with a cooling medium circulation pump and a radiator. The electronic control system includes an ECU, an electronic throttle, and a speed sensor. The ECU is electrically connected to the air pressure regulating valve, hydrogen pressure regulating valve, hydrogen flow valve, high-pressure water pump, water injection valve, hydrogen injector, cooling medium circulation pump, speed sensor, electronic throttle, and fuel injection pump of the diesel supply system.

[0006] The control methods for the engine system include: fuel supply strategy, compressed air supply strategy, combustion control strategy, water injection supply strategy, and forced circulation cooling strategy, among which:

[0007] (1) Fuel supply strategy

[0008] The ECU receives the signal from the speed sensor and determines the position of the top dead center, controls the fuel injection pump to start, and injects high-pressure diesel fuel into the combustion chamber through the fuel injector, and increases or decreases the amount of fuel in real time according to the position of the electronic throttle.

[0009] Upon receiving the speed sensor signal, the ECU controls the hydrogen pressure regulating valve to inject high-pressure hydrogen into the combustion chamber through the hydrogen injector.

[0010] (2) Compressed air supply strategy

[0011] Adjust the air pressure regulating valve according to changes in engine speed and load to allow pressurized air to enter the combustion chamber;

[0012] (3) Combustion control strategy

[0013] The ECU receives the speed sensor signal and determines the top dead center position. It controls the fuel injection pump to inject high-pressure diesel fuel into the combustion chamber through the fuel injector. At the same time, the ECU controls the hydrogen injection valve to be 180 degrees before the top dead center to inject hydrogen into the combustion chamber. The piston compresses the air in the combustion chamber to ignite the diesel fuel and ignite the hydrogen at the same time. The ECU adjusts the injection pulse width and injection timing of diesel fuel and hydrogen in real time according to the position of the electronic throttle.

[0014] (4) Spray control strategy

[0015] The ECU collects signals from the speed sensor, identifies the top dead center position, and controls the water injection valve to spray water when the engine is intake air. The water injection volume is controlled by the pulse width. The water injection timing and pulse width are determined based on the knock point and knock duration that appear in the engine's universal characteristic curve.

[0016] (5) Forced circulation cooling strategy

[0017] The cooling system uses a cooling medium circulation pump and radiator to create forced circulation cooling, maintaining its temperature at 30-45℃.

[0018] In this invention, by installing a high-pressure gas storage tank and an air pressure regulating valve in the air intake system, the air intake can be increased through intake pressurization, thereby increasing the hydrogen input and improving the hydrogen substitution rate. The hydrogen injector is arranged with its tilt direction and angle consistent with the air intake channel, allowing for a combination of airflow circulation, turbulence, positive pressure flow, and reverse pressure return flow. This ensures thorough mixing and combustion of hydrogen and air, improving hydrogen combustion efficiency, reducing the possibility of backflow and flashback, and fundamentally suppressing hydrogen explosion. Simultaneously, this arrangement also prevents air and hydrogen intake from interfering with each other, thus affecting the hydrogen injection volume and the concentration of the air mixture. This design improves combustion efficiency and engine performance. The hydrogen injector uses a large-diameter intake, a small-diameter outlet, and a spiral air passage, which increases the hydrogen injection pressure and sprays the hydrogen in a spiral shape to mix with air. This ensures that the hydrogen and air are fully mixed in the combustion chamber, improving combustion efficiency. Furthermore, the use of multiple hydrogen injection holes not only increases the hydrogen injection pressure and increases hydrogen output, allowing for rapid and thorough mixing and combustion with air and fuel, thus increasing calorific value, but also enhances airflow disturbance within the combustion chamber, improving hydrogen-air mixing and combustion efficiency. The water injection system in this invention, through a high-pressure water pump and injection valve, sprays water into the air intake pipe, which then enters the combustion chamber with the air. This reduces the instantaneous heat during hydrogen combustion and the rapid pressure increase, thereby reducing knocking during hydrogen combustion. The forced circulation cooling system improves cooling efficiency, ensuring the engine operates at its best and increasing hydrogen substitution rate. The electronic control system controls the air pressure regulating valve, hydrogen pressure regulating valve, hydrogen flow valve, high-pressure water pump, water injection valve, coolant circulation pump, hydrogen injector, and fuel injection pump. The ECU adjusts the hydrogen and water injection pressures based on the electronic throttle position. The ECU can also use the speed sensor to determine the engine speed and top dead center position, and control the timing and pulse width of diesel, hydrogen, and water injections, as well as the air intake pressure and flow rate, and the optimal cooling temperature of the coolant.

[0019] Furthermore, the air intake system pressure is 0.06-0.1 MPa.

[0020] Furthermore, the hydrogen injection pulse width is 64°CA. Setting the hydrogen injection pulse width to 64°CA can increase the amount of hydrogen injected and improve the hydrogen substitution rate.

[0021] Furthermore, the hydrogen injection timing is 120°CA BTDC. Setting the hydrogen injection timing to 120°CA BTDC avoids injecting hydrogen at the end of piston compression, reduces the hydrogen injection pressure environment, ensures the amount of hydrogen injected, improves the hydrogen substitution rate, and ensures engine efficiency.

[0022] Furthermore, the operating temperature of the cooling system is 35°C.

[0023] Furthermore, there are 3-4 hydrogen injection holes.

[0024] Furthermore, to avoid the hydrogen entering the combustion chamber from colliding with the air entering the combustion chamber through the air intake channel, thus affecting the hydrogen injection quantity and the concentration of the air mixture, the outlet end of the hydrogen injector is an arc surface, and there are three hydrogen injection holes, all of which are located on the side of the outlet end of the hydrogen injector away from the air intake channel.

[0025] Furthermore, on the orthographic projection of the hydrogen injector's outlet end, the three hydrogen injection holes are evenly arranged on the same semicircle.

[0026] Furthermore, to prevent the hydrogen entering the combustion chamber from colliding with the air entering the combustion chamber through the air intake channel, thus affecting the hydrogen injection volume and the concentration of the air mixture, the outlet end of the hydrogen injector is an arc surface, and the hydrogen injection holes are four evenly arranged. A guide shroud is fixedly installed on the outside of the outlet end of the hydrogen injector near the air intake channel.

[0027] Furthermore, a flame arrestor seal is installed between the outlet end of the hydrogen injector and the cylinder head. This flame arrestor seal improves the seal between the hydrogen injector and the cylinder head, preventing flame spread between them and enhancing safety.

[0028] The beneficial effects of this invention are as follows: By incorporating a high-pressure gas storage tank and an air pressure regulating valve into the air intake system, the invention can increase the air intake volume through intake pressurization, thereby increasing the hydrogen input volume and thus improving the hydrogen substitution rate. Compared with natural aspiration, the hydrogen substitution rate is increased by 35.5%, while simultaneously reducing fuel consumption. Furthermore, the hydrogen injector is arranged with its tilt direction and angle aligned with the air intake channel, allowing for a combination of airflow circulation, turbulence, positive pressure flow, and reverse pressure return flow. This ensures thorough mixing and combustion of hydrogen and air, improving hydrogen combustion efficiency, reducing the possibility of backfire and backfire, and fundamentally suppressing hydrogen explosions. This arrangement also prevents air and hydrogen intake from interfering with each other, thus ensuring adequate hydrogen-air mixing, improved combustion efficiency, and enhanced engine performance. The hydrogen injector uses a large-diameter intake, a small-diameter outlet, and a spiral air passage to increase hydrogen injection pressure and spray hydrogen in a spiral pattern to mix with air. This ensures thorough mixing of hydrogen and air within the combustion chamber, improving combustion efficiency. Furthermore, the multiple hydrogen injection holes and multi-flow design enhance airflow disturbance within the combustion chamber, further improving hydrogen-air mixing and combustion efficiency. By installing a water spray system to inject water into the air intake pipe, detonation during hydrogen combustion is reduced, increasing hydrogen input and improving the hydrogen substitution rate. Through detonation reduction, the hydrogen substitution rate can reach up to approximately 95%, significantly reducing pollutant emissions. The forced circulation cooling system improves the cooling effect of the engine cooling system, reduces fuel consumption, and increases the hydrogen substitution rate. Tests have shown that the hydrogen substitution rate has increased by 17.7%. The electronic control system can control the diesel supply system, hydrogen supply system, water injection system, air intake system, and cooling system, enabling precise fuel control. This ensures that the engine is in optimal operating condition, improves the hydrogen substitution rate, reduces fuel consumption, enhances engine economy and reliability, and significantly reduces sulfur oxide and particulate matter emissions. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a compression ignition hydrogen-diesel hybrid single-cylinder engine system according to an embodiment of the present invention (the cylinder head of the engine is not shown).

[0030] Figure 2 This is a schematic diagram of the structure of the engine cylinder head in an embodiment of the present invention;

[0031] Figure 3 yes Figure 2 An enlarged schematic diagram of part I in the diagram;

[0032] Figure 4 This is a schematic diagram of the hydrogen injector in this invention;

[0033] Figure 5 yes Figure 4An enlarged schematic diagram of part H in the diagram;

[0034] Figure 6 This is a front view schematic diagram of a hydrogen injector with three hydrogen injection holes;

[0035] Figure 7 yes Figure 6 A schematic diagram of direction D in the diagram;

[0036] Figure 8 This is a front view schematic diagram of a hydrogen injector with four hydrogen injection holes;

[0037] Figure 9 yes Figure 8 A schematic diagram of direction B in the diagram;

[0038] Figure 10 This is a schematic diagram of the speed sensor installation.

[0039] In the diagram, A1 is the air intake system, A2 is the diesel fuel supply system, A3 is the hydrogen supply system, A4 is the water injection system, and A5 is the electronic control system.

[0040] 1. Hydrogen tank; 2. Hydrogen pressure regulating valve; 3. Hydrogen flow valve; 4. Water tank; 5. High-pressure water pump; 6. High-pressure gas storage tank; 7. Air pressure regulating valve; 8. Air filter; 9. Speed ​​sensor; 10. Crankshaft; 11. Engine cylinder liner; 12. Piston; 13. Combustion chamber; 14. Intake valve; 15. Water injection valve; 16. Hydrogen injector; 17. Fuel injector; 18. Flame arrester; 19. Exhaust valve; 20. Electronic throttle. 21. Camshaft; 22. Fuel injection pump; 23. ECU; 24. Hydrogen intake line; 25. Water supply line; 26. Air intake line; 27. High-pressure fuel line; 28. Air intake passage; 29. ​​Engine cylinder head; 30. Flame arrestor seal; 31. Draft shield; 32. Engine block; 33. Flywheel; 34. Sensor bracket; 35. Sensor sensing hole; 161. Spiral air passage of hydrogen injector; 162. Hydrogen injection hole. Detailed Implementation

[0041] The invention will be further described below through non-limiting embodiments and in conjunction with the accompanying drawings:

[0042] As shown in the attached figure, a compression ignition hydrogen-diesel hybrid single-cylinder engine system includes an engine cylinder liner 11, a cylinder head 29 that mates with the engine cylinder liner 11, an air intake system A1, a diesel supply system A2, a hydrogen supply system A3, a water injection system A4, an electronic control system A5, and a cooling system (not shown in the attached figure).

[0043] The air intake system A1 includes a high-pressure air tank 6, which is connected to an air intake passage 28 on the cylinder head 29 via an air intake pipe 26. The air intake passage 28 is equipped with an intake valve 14 and communicates with the combustion chamber 13. An air pressure regulating valve 7 and an air filter 8 are installed on the air intake pipe 26. The air intake system A1 is used to supply air with a pressure greater than atmospheric pressure into the combustion chamber.

[0044] The diesel fuel supply system A2 includes a fuel injection pump 22, a fuel injector 17, and a high-pressure fuel line 27. The fuel injector 17 is mounted on the cylinder head 29 and communicates with the combustion chamber 13. One end of the high-pressure fuel line 27 is connected to the fuel injection pump 22, and the other end is connected to the fuel injector 17. The fuel injection pump 22 contacts the camshaft 21, converting the rotation of the camshaft 21 into linear motion of the fuel injection pump 22. The diesel fuel supply system A2 supplies diesel fuel to the fuel injector 17 through the fuel injection pump 22, and the fuel injector 17 injects the diesel fuel into the combustion chamber 13.

[0045] The hydrogen supply system A3 includes a hydrogen tank 1, a hydrogen pressure regulating valve 2, a hydrogen flow valve 3, a flame arrester 18, and a hydrogen injector 16, which are connected in sequence through a hydrogen intake pipe 24. The maximum pressure of the hydrogen tank is 14 MPa, and the maximum pressure displayed after pressure reduction is 2.5 MPa. The hydrogen injector 16 is mounted on the cylinder head 29 and communicates with the combustion chamber 13. The hydrogen supply system A3 injects hydrogen into the combustion chamber 13 through the hydrogen injector 16. The flame arrester 18 is used to prevent the spread of flame in the pipeline to prevent backfire and avoid explosion. The flame arrester 18 is existing technology. To prevent the air intake and hydrogen intake from interfering with each other and affecting the hydrogen injection volume and air-air mixture concentration, the hydrogen injector 16 is tilted, and its tilt direction and tilt angle are consistent with those of the air intake channel 28. To ensure thorough mixing of hydrogen and air within the combustion chamber 13, the hydrogen injector 16 employs a pressurized spiral air duct structure with a large-diameter inlet and a small-diameter outlet. Specifically, the diameter of the outlet end of the hydrogen injector 16 is smaller than the diameter of the inlet end. A spiral air duct 161 is provided inside the outlet end of the hydrogen injector 16, and the hydrogen injection holes 162 communicate with the inner cavity of the hydrogen injector 16 through the spiral air duct 161. Multiple hydrogen injection holes 162 are provided at the outlet end of the hydrogen injector 16, and each hydrogen injection hole 162 communicates with the inner cavity of the hydrogen injector 16 through a spiral air duct 161. The spiral air duct 161 allows hydrogen to be ejected in a spiral form and thoroughly mixed with air. Preferably, the number of hydrogen injection holes 162 is 3-4. To prevent flame spread between the hydrogen injector 16 and the cylinder head 29 and improve safety, it is preferable to provide a flame arrestor seal 30 between the outer side of the outlet end of the hydrogen injector 16 and the cylinder head. The flame arrestor seal 30 is made of high-temperature resistant silicone rubber, which is available in the prior art.

[0046] To improve the mixing of hydrogen and air and prevent the air intake and hydrogen intake from interfering with each other and affecting the hydrogen injection volume and air mixture concentration, it is preferable that the outlet end of the hydrogen injector 16 has an arc-shaped surface, and there are three hydrogen injection holes 162, all of which are located on the side of the outlet end of the hydrogen injector 16 away from the air intake channel 28. (See attached...) Figures 6-7 As shown, it is further preferred that the three hydrogen injection holes 162 are evenly arranged on the same semicircle on the orthographic projection of the outlet end of the hydrogen injector 16, so that the side of the outlet end of the hydrogen injector 16 without hydrogen injection holes 16 is close to the air intake channel 28, thereby preventing the air intake and hydrogen intake from interfering with each other and affecting the hydrogen injection volume and the concentration of air mixture.

[0047] As attached Figures 8-9 As shown, similarly, to improve the mixing of hydrogen and air and prevent the air intake and hydrogen intake from interfering with each other and affecting the hydrogen injection volume and air mixing concentration, it is preferable that the outlet end of the hydrogen injector 16 is an arc surface, and there are four hydrogen injection holes 162. The four hydrogen injection holes 162 are evenly arranged on the arc surface of the outlet end of the hydrogen injector 16. A flow guide shroud 31 is fixedly installed on the outside of the outlet end of the hydrogen injector 16 near the air intake channel 28. The flow guide shroud 31 covers the outside of the hydrogen injection holes 162 on this side and is used to guide the injected hydrogen to avoid the hydrogen and air entering from the air intake channel from interfering with each other and affecting the hydrogen injection volume and air mixing concentration.

[0048] The water spray system A4 includes a water tank 4, a high-pressure water pump 5, and a water spray valve 15, which are connected in sequence via a water supply pipe 25. The water spray valve 15 is connected to the air intake pipe 26 of the air intake system A1. The water spray system A4 can spray water into the air intake pipe 26 through the water spray valve 15, and the water will enter the combustion chamber with the air, reducing the hydrogen combustion rate and preventing the hydrogen from burning too quickly, thereby reducing the probability of knocking. The water spray valve 15 is the same as the spray valve used in automotive urea systems.

[0049] The cooling system is used to regulate engine temperature. It is a forced-circulation cooling system, which adds a cooling medium circulation pump and a radiator to a traditional evaporative water cooling system to form forced-circulation water cooling. Of course, the cooling medium in this invention is not limited to coolant; it can also be coolant or other cooling media. The electronic control system A5 includes an ECU 23, an electronic throttle 20, and a speed sensor 9. The ECU 23 is electrically connected to the air pressure regulating valve 7, the hydrogen pressure regulating valve 2, the hydrogen flow valve 3, the high-pressure water pump 5, the water injection valve 15, the hydrogen injector 16, the cooling medium circulation pump, the speed sensor 9, the electronic throttle 20, and the fuel injection pump 22. The ECU is existing technology. The electronic throttle 20 is fixed to the engine block 32, and it is linked to the mechanical throttle via a connecting rod. The speed sensor 9 is mounted on the engine block 32 via the sensor bracket 34, and the flywheel 33 is rotatably mounted on the engine block 32 via the crankshaft 10. The outer circumference of the flywheel 33 is evenly distributed with 58 sensor sensing holes 35 and 2 missing tooth holes, with the missing tooth holes forming a 60-degree angle with the top dead center of the flywheel. The axis of the speed sensor 9 overlaps with the center line of the sensor sensing holes 35, and the gap between the front end face of the speed sensor 9 and the outer circumference of the flywheel 33 is 1.5-2.5 mm. The ECU interacts with the air pressure regulating valve 7, hydrogen pressure regulating valve 2, hydrogen flow valve 3, high-pressure water pump 5, water injection valve 15, hydrogen injector 16, coolant circulation pump, speed sensor 9, electronic throttle 20, and fuel injection pump 22. The ECU can adjust the hydrogen injection pressure and water injection pressure according to the position of the electronic throttle. The ECU can determine the engine speed and top dead center position through the speed sensor to control the timing and pulse width of diesel, hydrogen, and water injection.

[0050] The control methods for the engine system include: fuel supply strategy, compressed air supply strategy, combustion control strategy, water injection supply strategy, and forced circulation cooling strategy, among which:

[0051] (1) Fuel supply strategy

[0052] The rotation of the crankshaft 10 drives the camshaft 21 to rotate and causes the fuel injection pump 22 to generate high-pressure oil; the ECU 23 receives the signal from the speed sensor 9 and determines the position of the top dead center, controls the fuel injection pump 22 to open, and injects high-pressure diesel fuel into the combustion chamber 13 through the fuel injector 17, and increases or decreases the amount of fuel in real time according to the position of the electronic throttle 20.

[0053] When the ECU23 receives the signal from the speed sensor 9, it controls the hydrogen pressure regulating valve 2 to inject high-pressure hydrogen into the combustion chamber 13 through the hydrogen injector 16.

[0054] (2) Compressed air supply strategy

[0055] The air pressure regulating valve 7 is adjusted according to changes in engine speed and load to allow pressurized air to enter the combustion chamber, ensuring sufficient air and oxygen to facilitate the complete combustion of diesel and hydrogen fuels. Preferably, the air intake system pressure is 0.06-0.1 MPa.

[0056] (3) Combustion control strategy

[0057] The ECU receives the signal from the speed sensor 9 and determines the top dead center position. It then controls the fuel injection pump 22 to inject high-pressure diesel fuel into the combustion chamber 13 through the fuel injector 17. Simultaneously, the ECU controls the hydrogen injection valve 16 to be 180 degrees before top dead center, injecting hydrogen into the combustion chamber 13. The crankshaft 10 rotates, causing the piston to move upwards. The piston compresses the air, igniting the diesel fuel in the combustion chamber and simultaneously igniting the hydrogen. The ECU adjusts the injection pulse width and injection timing of diesel and hydrogen in real time based on the position of the electronic throttle 20. Preferably, the hydrogen injection pulse width is 64°CA. Setting the hydrogen injection pulse width to 64°CA increases the hydrogen injection quantity and improves the hydrogen substitution rate. Preferably, the hydrogen injection timing is 120°CA BTDC. Setting the hydrogen injection timing to 120°CA BTDC avoids injecting hydrogen at the end of piston compression, reducing the hydrogen injection pressure environment, ensuring the hydrogen injection quantity, improving the hydrogen substitution rate, and ensuring engine efficiency.

[0058] (4) Spray control strategy

[0059] The ECU collects signals from the speed sensor, identifies the top dead center position, and controls the water injection valve to spray water at the engine intake moment, controlling the water injection volume through pulse width modulation. The water injection timing and pulse width are determined based on the knock point and knock duration appearing in the engine's universal characteristic curve. By spraying water into the air intake manifold, the water enters the combustion chamber with the air, reducing the instantaneous heat during hydrogen combustion and the rapid pressure rise, thereby reducing knocking during hydrogen combustion. This increases the amount of hydrogen input, improves the hydrogen substitution rate, and reduces fuel consumption.

[0060] (5) Forced circulation cooling strategy

[0061] The cooling system utilizes a cooling medium circulation pump and radiator to create forced water cooling, maintaining a certain operating temperature to ensure the engine operates at optimal conditions, thereby reducing fuel consumption and increasing hydrogen substitution efficiency. Maintaining the cooling system's operating temperature between 30-45°C ensures optimal engine performance and improves hydrogen substitution efficiency; preferably, the operating temperature is 35°C.

[0062] The electronic control system controls the air pressure regulating valve, hydrogen pressure regulating valve, hydrogen flow valve, high-pressure water pump, water injection valve, coolant circulation pump, hydrogen injector, and fuel injection pump. Based on test data and the engine's universal characteristic curve, the ECU intelligent control program can be formed. The hydrogen injection pressure and water injection pressure are adjusted according to the electronic throttle position. The ECU can determine the engine speed and top dead center position through the speed sensor, and control the timing and pulse width of diesel, hydrogen, and water injection, as well as the air intake pressure and flow rate, and the optimal cooling temperature of the coolant online to meet the power and torque requirements, improve the hydrogen substitution rate, and achieve the most energy-saving goal.

[0063] This invention effectively improves the hydrogen substitution rate and enhances engine efficiency by employing methods such as air intake pressurization, water injection into the air intake pipe during detonation, a forced circulation cooling system, an angled hydrogen injector, and control of hydrogen injection timing and pulse width. Using the above-mentioned techniques, experiments were conducted to improve the hydrogen substitution rate under different conditions. In the air intake boosting experiment, compared with the naturally aspirated system, the hydrogen substitution rate increased by 35.5% through intake boosting. In the forced circulating water cooling experiment, by enhancing the performance of the water cooling system, the hydrogen substitution rate increased by 17.7% while maintaining the cooling system operating temperature at 30-45℃, resulting in a reduction in fuel consumption. The optimal operating temperature for the cooling system was 35℃. In the hydrogen injection pulse width experiment, adjusting the injection pulse width from 190°CA to 64°CA resulted in a significant improvement in the hydrogen substitution rate, increasing it by 2.2%. In the hydrogen injection timing experiment, delaying the hydrogen injection timing from 180°CABTDC to 120°CABTDC increased the hydrogen substitution rate by 20%. Under forced circulating water cooling, air intake boosting, and a hydrogen injection pulse width of 64°CA, adjusting the hydrogen injection timing and delaying it to 120°CABTDC resulted in a hydrogen substitution rate of 93.8%.

[0064] To verify that the present invention can improve the hydrogen substitution rate under high power conditions, an experiment on the hydrogen substitution rate under high power conditions was conducted, and the experimental data are shown in Table 1.

[0065] Table 1 shows the experimental data of hydrogen substitution rate under high-power conditions according to this invention.

[0066]

[0067] As shown in Table 1, the hydrogen substitution rate of this invention can reach 93.83% under 13.3kW operating conditions and 82.46% under 14.7kW operating conditions. This demonstrates that this invention can improve the hydrogen substitution rate and reduce fuel consumption under high-power operating conditions, thereby improving engine economy and reliability, and significantly reducing sulfur oxide and particulate matter emissions.

[0068] The other parts in this embodiment are all existing technologies and will not be described in detail here.

Claims

1. A control method for a compression-ignition hydrogen-diesel hybrid single-cylinder engine system, the compression-ignition hydrogen-diesel hybrid single-cylinder engine system comprising a cylinder head that mates with the engine's cylinder liner, an air intake system, a diesel supply system, a hydrogen supply system, a cooling system, and an electronic control system, characterized in that: The air intake system includes a high-pressure gas tank, which is connected to the air intake channel on the cylinder head via an air intake pipe. An air pressure regulating valve is installed on the air intake pipe. The hydrogen supply system includes a hydrogen tank, a hydrogen pressure regulating valve, a hydrogen flow valve, a flame arrester, and a hydrogen injector, connected sequentially via a hydrogen intake pipe. The hydrogen injector is mounted on the cylinder head and communicates with the combustion chamber. The hydrogen injector is tilted, and its tilt direction and angle are consistent with the air intake channel. The diameter of the hydrogen injector's outlet end is smaller than the diameter of its inlet end. Multiple hydrogen injection holes are provided at the outlet end of the hydrogen injector. These injection holes pass through the inner end of the hydrogen injector's outlet end... The spiral air passage is connected to the inner cavity of the hydrogen injector; it also includes a water injection system, which includes a water tank, a high-pressure water pump, and a water injection valve connected in sequence through a water supply pipeline. The water injection valve is connected to the air intake pipeline of the air intake system; the cooling system is a forced circulation cooling system, which is equipped with a cooling medium circulation pump and a radiator; the electronic control system includes an ECU, an electronic throttle, and a speed sensor. The ECU is electrically connected to the air pressure regulating valve, the hydrogen pressure regulating valve, the hydrogen flow valve, the high-pressure water pump, the water injection valve, the hydrogen injector, the cooling medium circulation pump, the speed sensor, the electronic throttle, and the fuel injection pump of the diesel supply system. The control methods for the engine system include: fuel supply strategy, compressed air supply strategy, combustion control strategy, water injection supply strategy, and forced circulation cooling strategy, among which: (1) Fuel supply strategy The ECU receives the signal from the speed sensor and determines the position of the top dead center, controls the fuel injection pump to start, and injects high-pressure diesel fuel into the combustion chamber through the fuel injector, and increases or decreases the amount of fuel in real time according to the position of the electronic throttle. When the ECU (23) receives the speed sensor signal, it controls the hydrogen pressure regulating valve to inject high-pressure hydrogen into the combustion chamber through the hydrogen injector (16); (2) Compressed air supply strategy Adjust the air pressure regulating valve according to changes in engine speed and load to allow pressurized air to enter the combustion chamber; (3) Combustion control strategy The ECU receives the speed sensor signal and determines the top dead center position. It controls the fuel injection pump to inject high-pressure diesel fuel into the combustion chamber through the fuel injector. At the same time, the ECU controls the hydrogen injection valve to be 180 degrees before the top dead center to inject hydrogen into the combustion chamber. The piston compresses the air in the combustion chamber to ignite the diesel fuel and hydrogen at the same time. The ECU adjusts the injection pulse width and injection timing of diesel fuel and hydrogen in real time according to the position of the electronic throttle. (4) Spray control strategy The ECU collects signals from the speed sensor, identifies the top dead center position, and controls the water injection valve to spray water when the engine is intake air. The water injection volume is controlled by the pulse width. The water injection timing and pulse width are determined based on the knock point and knock duration that appear in the engine's universal characteristic curve. (5) Forced circulation cooling strategy The cooling system uses a cooling medium circulation pump and radiator to create forced circulation cooling, maintaining its temperature at 30-45℃.

2. The control method for the compression ignition hydrogen-diesel hybrid single-cylinder engine system according to claim 1, characterized in that: The air intake system pressure is 0.06-0.1 MPa.

3. The control method for the compression ignition hydrogen-diesel hybrid single-cylinder engine system according to claim 2, characterized in that: The hydrogen injection pulse width is 64°CA.

4. The control method for the compression ignition hydrogen-diesel hybrid single-cylinder engine system according to claim 2, characterized in that: The hydrogen injection timing is 120°CA BTDC.

5. The control method for the compression ignition hydrogen-diesel hybrid single-cylinder engine system according to claim 2, characterized in that: The operating temperature of the cooling system is 35℃.

6. The control method for a compression ignition hydrogen-diesel hybrid single-cylinder engine system according to claim 1, 2, 3, 4, or 5, characterized in that: There are 3-4 hydrogen injection holes.

7. The control method for the compression ignition hydrogen-diesel hybrid single-cylinder engine system according to claim 6, characterized in that: The outlet end of the hydrogen injector is an arc-shaped surface, and there are three hydrogen injection holes, all of which are located on the side of the outlet end of the hydrogen injector away from the air intake channel.

8. The compression ignition hydrogen-diesel hybrid single-cylinder engine system according to claim 7, characterized in that: On the orthographic projection of the hydrogen injector outlet end, three hydrogen injection holes are evenly arranged on the same semicircle.

9. The control method for the compression ignition hydrogen-diesel hybrid single-cylinder engine system according to claim 6, characterized in that: The outlet end of the hydrogen injector is an arc surface, and there are four hydrogen injection holes evenly arranged. A flow guide is fixedly installed on the outside of the outlet end of the hydrogen injector near the air inlet channel.

10. The control method for the compression ignition hydrogen-diesel hybrid single-cylinder engine system according to claim 1, characterized in that: A flame arrestor seal is installed between the outlet end of the hydrogen injector and the cylinder head.

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