Water-hydrogen-electricity combined supply internal combustion engine

Abstract

The present application relates to hydrogen internal combustion engine technical field, especially to a kind of water hydrogen electricity combined supply internal combustion engine, including by hydrogen internal combustion engine unit combustion hydrogen and air driven first power generation unit;Gas recovery unit by condensation drive module converts water vapor in exhaust gas into liquid water, while driving second power generation unit;Fuel supply unit is based on the multidimensional data obtained by monitoring unit detection, through the processing of data processing unit and confidence decision unit, the generated adjustment instruction adjusts hydrogen injection amount, and then inhibits the generation of nitrogen oxides.The present application combines the condensate water recovery of hydrogen internal combustion engine with the combustion control deeply, the actual humidity of exhaust gas is deduced by monitoring the condensate water flow, the error tolerance range of gas detection is dynamically corrected, and the safety limit control of hydrogen fuel supply is realized by the determination result of hydrogen-oxygen combustion ratio, to reduce the generation of nitrogen oxides of hydrogen internal combustion engine.

Description

Technical Field

[0001] This invention relates to the field of hydrogen internal combustion engine technology, and more particularly to a water-hydrogen-electricity combined cycle internal combustion engine. Background Technology

[0002] As a key direction for future clean energy technologies, hydrogen internal combustion engines replace carbon-containing fuels such as gasoline, diesel, and natural gas with hydrogen, significantly reducing carbon dioxide emissions. Their advantages lie in high output power, high thermal efficiency, and energy-saving and environmentally friendly characteristics. However, this technology also faces combustion control challenges such as detonation, pre-ignition, and backfire, and still produces nitrogen oxides (NOx) during operation. Therefore, improving the performance of the power system and effectively suppressing NOx emissions have become the core research and development goals for hydrogen internal combustion engines.

[0003] Hydrogen has a wide combustible range in air, from 4% to 75%, which provides considerable operational flexibility for combustion control. However, the challenge lies in the fact that under high-temperature and oxygen-rich conditions, hydrogen combustion can promote the reaction of nitrogen in the air to generate NOx pollutants. To suppress NOx formation, the key is to control the combustion temperature at a low level, which is usually achieved by precisely adjusting the excess air coefficient. Precise control of the excess air coefficient can not only avoid pre-ignition and knocking caused by an overly rich mixture, thus improving engine stability, but also prevent misfires caused by an overly lean mixture. Currently, most mainstream hydrogen internal combustion engines adopt a lean combustion strategy with an excess air coefficient in the range of 1.8 to 3.0.

[0004] Meanwhile, exhaust gas recirculation (EGR) technology is one of the effective means to reduce nitrogen oxide emissions from internal combustion engines. Applying EGR can reduce in-cylinder heat transfer loss, increase the specific heat ratio of the working fluid, increase the isochoricity of combustion heat release, and improve the engine's anti-knock performance, thereby improving the engine's thermal efficiency. In the exhaust gas, how to better utilize the high-temperature, high-pressure water vapor generated by hydrogen-oxygen combustion is a key research and development direction for hydrogen internal combustion engines. It has important practical significance for applications such as long-distance ship power, offshore island power generation, and water resource recycling.

[0005] Existing methods for detecting and calculating excess air coefficients have limitations. The results show a large error compared to excess air coefficients measured in a laboratory environment using high-precision flow meters. This accuracy issue limits the practical application of the technology and urgently needs improvement.

[0006] Chinese Patent Publication No. CN115130280A discloses a method, apparatus, and turbocharged hydrogen internal combustion engine for selecting a turbocharger. The method involves calculating airflow and hydrogen flow based on the matching point of the hydrogen internal combustion engine and the excess air coefficient; calculating the mass fraction of exhaust components based on the chemical formula of the hydrogen-air reaction and the excess air coefficient; setting the exhaust temperature at the turbine inlet of the turbocharger and determining the isobaric specific heat capacity of the gas mixture constituting the exhaust at that set exhaust temperature based on the mass fraction of the exhaust components; calculating the theoretical value of the exhaust temperature at the turbine inlet based on the expected target effective thermal efficiency and heat transfer ratio at the matching point of the hydrogen internal combustion engine and the isobaric specific heat capacity of the gas mixture; determining the set exhaust temperature at the turbine inlet when the difference between the theoretical exhaust temperature and the set exhaust temperature at the turbine inlet is within a threshold value; and determining the turbine expansion ratio based on the determined exhaust temperature and the compressor parameters of the turbocharger. The turbocharger selected in this application exhibits better matching with the hydrogen internal combustion engine.

[0007] Therefore, the selection method, device, and turbocharged hydrogen internal combustion engine of the turbocharged hydrogen internal combustion engine have the following problems: the error in detecting and calculating the excess air coefficient is large, making it difficult to accurately determine the combustion state of the hydrogen internal combustion engine. Summary of the Invention

[0008] To address this issue, the present invention provides a water-hydrogen-electric combined cycle internal combustion engine to overcome the problem in the prior art where the error in detecting and calculating the excess air coefficient is large, making it difficult to accurately determine the combustion state of the hydrogen internal combustion engine, which leads to excessive nitrogen oxide generation.

[0009] To achieve the above objectives, the present invention provides a water-hydrogen-electric cogeneration internal combustion engine, comprising:

[0010] A hydrogen internal combustion engine unit, used to burn hydrogen and air to generate power;

[0011] The first power generation unit is connected to the output terminal of the hydrogen internal combustion engine unit to convert the mechanical energy generated by the hydrogen internal combustion engine unit into electrical energy.

[0012] A gas recovery unit, which is connected to the exhaust end of the hydrogen internal combustion engine unit, is used to convert the pressure of the gas discharged from the hydrogen internal combustion engine unit into mechanical energy, and at the same time condense the water vapor in the discharged gas.

[0013] The second power generation unit is connected to the gas recovery unit and converts the mechanical energy generated by the gas discharged from the hydrogen internal combustion engine unit into electrical energy.

[0014] The monitoring unit is connected to the second power generation unit and the gas recovery unit respectively, and is used to collect the voltage change rate output by the second power generation unit and the exhaust oxygen concentration, exhaust nitrogen oxide concentration and condensate flow rate of the exhaust gas in the gas recovery unit in real time.

[0015] A data processing unit, connected to the monitoring unit, is used to determine the hydrogen-oxygen combustion state of the hydrogen internal combustion engine unit based on the voltage change rate, and to obtain the actual humidity of the exhaust gas based on the condensate flow rate.

[0016] A confidence decision unit, which is connected to the monitoring unit and the data processing unit respectively, is used to calculate the excess air coefficient by comparing the exhaust oxygen concentration and the exhaust nitrogen oxide concentration respectively, and output the actual excess air coefficient according to the error tolerance range after correction of the actual exhaust humidity.

[0017] A fuel supply unit, which is connected to the confidence decision unit and the hydrogen internal combustion engine unit respectively, is used to dynamically adjust the amount of hydrogen injected into the hydrogen internal combustion engine unit when hydrogen is input, based on the deviation between the actual excess air coefficient and the target value of the excess air coefficient.

[0018] Furthermore, the gas recovery unit includes:

[0019] The condensation drive module has its air inlet connected to the exhaust end of the hydrogen internal combustion engine unit. It includes a rotatable drive gear with a first number of teeth and a driven gear with a second number of teeth. The drive gear is driven to rotate by the exhaust flow to cause periodic volume expansion of the meshing part through the difference in the number of teeth, forming a local low-pressure zone to condense water vapor.

[0020] A droplet separation module includes a cavity coaxial with the condensation drive module, used to give condensed droplets centrifugal acceleration and allow them to move along the inner wall;

[0021] A collection module, located outside the cavity of the droplet separation module, is used to receive and store the condensate after centrifugal separation;

[0022] The number of teeth in the first case is less than the number of teeth in the second case.

[0023] Furthermore, in the condensation drive module, the difference in the number of teeth between the first number of teeth of the driving gear and the second number of teeth of the driven gear is determined based on the difference between the volume expansion rate and the expansion rate threshold in a single meshing cycle, wherein the expansion rate threshold is determined by the power of the hydrogen internal combustion engine unit.

[0024] Furthermore, the data processing unit determines whether the hydrogen-oxygen combustion ratio of the hydrogen internal combustion engine unit is in a hydrogen-rich or hydrogen-lean state based on whether the voltage change rate output by the second power generation unit, which is collected in real time by the monitoring unit, is within a stable range.

[0025] If the voltage change rate is within a stable range, the hydrogen-oxygen combustion ratio of the hydrogen internal combustion engine unit is determined to be in a hydrogen-rich state.

[0026] If the voltage change rate is not within the stable range, the hydrogen-oxygen combustion ratio of the hydrogen internal combustion engine unit is determined to be in a hydrogen-deficient state.

[0027] Furthermore, the confidence decision unit corrects the slope parameter of the basic pre-stored relationship curve based on the determination result of the hydrogen-oxygen combustion ratio obtained by the data processing unit, and obtains the corrected pre-stored relationship curve.

[0028] Furthermore, the confidence decision unit,

[0029] Based on the aforementioned exhaust oxygen concentration and modified pre-stored relationship curve, the first excess air coefficient is determined;

[0030] The second excess air coefficient is determined based on the relationship curve between the exhaust nitrogen oxide concentration and the corrected pre-stored data.

[0031] The preset error tolerance range is corrected based on the actual exhaust humidity, wherein the actual exhaust humidity is determined based on the condensate flow rate.

[0032] Furthermore, the confidence decision unit determines the weighted average of the first excess air coefficient and the second excess air coefficient as the actual excess air coefficient based on the comparison result that the deviation between the first excess air coefficient and the second excess air coefficient is within the corrected error tolerance range.

[0033] Furthermore, the confidence decision unit determines the corresponding actual excess air coefficient value based on the comparison result of the deviation exceeding the error tolerance range and the determination result of the hydrogen-oxygen combustion ratio.

[0034] Furthermore, the fuel supply unit dynamically adjusts the hydrogen injection quantity based on the deviation between the actual excess air coefficient and the target value of the excess air coefficient, wherein...

[0035] If the hydrogen-oxygen combustion ratio is determined to be in a hydrogen-deficient state, then the reduction range of hydrogen injection quantity will be limited.

[0036] If the hydrogen-oxygen combustion ratio is determined to be in a hydrogen-rich state, then the upward adjustment of the hydrogen injection quantity will be limited.

[0037] Furthermore, the fuel supply unit adjusts the hydrogen injection quantity by adjusting the injection pulse width of the hydrogen fuel injection valve.

[0038] Compared with existing technologies, the advantages of this invention lie in its ability to creatively achieve the dual functions of water recovery and combustion diagnosis by using the condensate collected by the gas recovery unit as a natural tracer to infer the actual humidity of the exhaust gas in real time and correct control parameters. While collecting liquid water for resource recycling, the invention also utilizes the strict correlation between water generation and combustion state to construct a self-calibrating detection system that eliminates the need for additional humidity sensors. This reduces system complexity and avoids external interference, ensuring that the water-hydrogen-electricity cogeneration system maintains synergistic optimization of efficient water recovery and precise combustion control under varying operating conditions.

[0039] Furthermore, this invention uses a dynamic design of the gear set tooth difference in the condensation drive module to match the volume expansion rate with the power of the hydrogen internal combustion engine. During the process of recovering water vapor, the exhaust pressure energy is simultaneously converted into mechanical energy to drive the second power generation unit to generate electricity efficiently, eliminating the energy conversion loss of traditional waste heat recovery systems and significantly improving the overall energy utilization rate.

[0040] Furthermore, based on voltage fluctuation characteristics and a dual excess air coefficient arbitration mechanism, this invention constructs a combustion state classification judgment system. By constraining the fuel adjustment range by combustion state, it effectively avoids the risks of hydrogen-deficient misfire and hydrogen-rich knock. At the same time, by utilizing humidity-corrected error tolerance dynamic scaling technology, it significantly improves control robustness under extreme operating conditions.

[0041] Furthermore, this invention integrates sensor conflict analysis and combustion status verification in gas composition detection. When the oxygen concentration and nitrogen oxide detection values ​​exceed the tolerance, the system automatically switches the priority data source and triggers a failure counter to lock the faulty sensor. This design enables the system to have online self-diagnosis capabilities, reduces the frequency of downtime maintenance, and extends the service life of key components.

[0042] Furthermore, this invention employs a bidirectional dynamic limiting mechanism for fuel injection quantity to restrict the downward adjustment of hydrogen in a hydrogen-deficient state to prevent lean-burn misfire, and to restrict the upward adjustment in a hydrogen-rich state to suppress abnormal combustion. Combined with precise pulse width control synchronized with the crankshaft, this forms a multi-level safety protection, eliminating safety hazards such as backfire and pre-ignition in hydrogen internal combustion engines.

[0043] Furthermore, relying on the intrinsic characteristics of hydrogen combustion to produce water, this invention establishes a closed-loop correction chain of condensate flow rate, exhaust humidity, and gas detection error, thereby achieving simultaneous improvement in water recovery rate, power generation efficiency, and combustion efficiency. The entire system achieves cogeneration and supply of water, hydrogen, and electricity with zero external energy consumption, constructing a completely self-sustaining clean energy cycle system. Attached Figure Description

[0044] Figure 1 This is a connection block diagram of the water-hydrogen-electricity combined cycle internal combustion engine of the present invention;

[0045] Figure 2This is a schematic diagram of the gas recovery unit of the water-hydrogen-electricity cogeneration internal combustion engine of the present invention;

[0046] Figure 3 This is a logic diagram for obtaining the first excess air coefficient and the second excess air coefficient in the water-hydrogen-electricity combined cycle internal combustion engine of the present invention.

[0047] Figure 4 This is a logic diagram of the water-hydrogen-electricity combined cycle internal combustion engine of the present invention for adjusting the amount of hydrogen injection.

[0048] In the diagram, 111-inlet cavity; 112-outlet cavity; 121-air inlet; 122-air outlet; 131-driving gear; 132-driven gear; 14-conveying chamber; 2-droplet separation module. Detailed Implementation

[0049] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0050] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0051] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0052] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] Please see Figure 1 As shown, it is a connection block diagram of the water-hydrogen-electricity combined cycle internal combustion engine of the present invention, including:

[0054] A hydrogen internal combustion engine unit, used to burn hydrogen and air to generate power;

[0055] The first power generation unit is connected to the output terminal of the hydrogen internal combustion engine unit to convert the mechanical energy generated by the hydrogen internal combustion engine unit into electrical energy.

[0056] A gas recovery unit, which is connected to the exhaust end of the hydrogen internal combustion engine unit, is used to convert the pressure of the gas discharged from the hydrogen internal combustion engine unit into mechanical energy, and at the same time condense the water vapor in the discharged gas.

[0057] The second power generation unit is connected to the gas recovery unit and converts the mechanical energy generated by the gas discharged from the hydrogen internal combustion engine unit into electrical energy.

[0058] The monitoring unit is connected to the second power generation unit and the gas recovery unit respectively, and is used to collect the voltage change rate output by the second power generation unit and the exhaust oxygen concentration, exhaust nitrogen oxide concentration and condensate flow rate of the exhaust gas in the gas recovery unit in real time.

[0059] In implementation, the monitoring unit accurately captures key operational data through four types of sensors: for monitoring the voltage change rate of the second power generation unit, a high-precision voltage sensor is used, which is directly installed on the three-phase output bus of the power generation unit to capture instantaneous fluctuations in power output in real time; for the synchronous detection of exhaust oxygen concentration and nitrogen oxide concentration, a wide-range oxygen sensor and an electrochemical nitrogen oxide sensor are integrated in parallel in a straight pipe section 15cm to 30cm upstream of the inlet flange of the gas recovery unit to ensure that undisturbed and stable gas composition data are obtained before the exhaust enters the condensation module; the monitoring of condensate flow rate is achieved through a corrosion-resistant turbine flow meter, which is horizontally embedded in the middle section of the drainage pipe of the collection module to directly measure the output of separated liquid water.

[0060] A data processing unit, connected to the monitoring unit, is used to determine the hydrogen-oxygen combustion state of the hydrogen internal combustion engine unit based on the voltage change rate, and to obtain the actual humidity of the exhaust gas based on the condensate flow rate.

[0061] A confidence decision unit, which is connected to the monitoring unit and the data processing unit respectively, is used to calculate the excess air coefficient by comparing the exhaust oxygen concentration and the exhaust nitrogen oxide concentration respectively, and output the actual excess air coefficient according to the error tolerance range after correction of the actual exhaust humidity.

[0062] A fuel supply unit is used to dynamically adjust the amount of hydrogen injected into the hydrogen internal combustion engine unit based on the deviation between the actual excess air coefficient and the target value of the excess air coefficient.

[0063] Please continue reading. Figure 2 As shown, this is a schematic diagram of the gas recovery unit of the water-hydrogen-electricity cogeneration internal combustion engine of the present invention. Specifically, the gas recovery unit includes:

[0064] The condensation drive module has an air inlet 121 connected to the exhaust end of the hydrogen internal combustion engine unit. It includes a rotatable drive gear 131 with a first number of teeth and a driven gear 132 with a second number of teeth. The drive gear 131 is driven to rotate by the exhaust flow to cause periodic volume expansion of the meshing part through the difference in the number of teeth, forming a local low-pressure area to condense water vapor.

[0065] The number of teeth in the first case is less than the number of teeth in the second case.

[0066] In implementation, the condensation drive module has a gear pump-like structure, including an inlet chamber 111, an outlet chamber 112, an air inlet 121, an air outlet 122, a drive gear 131, and a driven gear 132. The inlet chamber 111 is directly connected to the exhaust end of the hydrogen internal combustion engine unit. The drive gear 131 and the driven gear 132 have the same module and mesh with each other. The air intake direction of the air inlet 121 is set along the tangent direction of the drive gear 131 so that the exhaust airflow drives the drive gear 131 to rotate. The drive gear 131 has fewer teeth and is directly driven to rotate by the exhaust airflow. The driven gear 132 has significantly more teeth than the drive gear 131, forming a tooth difference with the drive gear 131, which is used to generate periodic volume expansion in the meshing area of ​​the two gears through the tooth difference. The shaft of the drive gear 131 is connected to the input shaft of the second power generation unit through a coupling, converting the exhaust pressure into rotational mechanical energy to drive the second power generation unit to generate electricity.

[0067] Understandably, gear pumps with unequal tooth counts utilize the speed difference between the driving gear 131 and the driven gear 132 to create a meshing phase misalignment, thereby generating a sudden volume expansion within a single meshing cycle. When the driving gear 131 with fewer teeth is driven to rotate by the exhaust, the driven gear 132 with more teeth rotates at a lower speed, causing the tooth grooves of the two gears to not be fully aligned at the moment of meshing. The tooth tip of the driving gear 131 disengages from the tooth root of the driven gear 132 in advance, instantly creating a wedge-shaped negative pressure chamber in the meshing area. This speed mismatch caused by the tooth count difference makes the volume expansion rate much higher than the linear change of a gear pump with equal tooth counts, resulting in a larger pressure drop. This forces the water vapor in the high-temperature exhaust to reach the dew point temperature under adiabatic expansion and condense instantaneously. At the same time, the high-speed rotating gears throw the generated droplets against the chamber wall, achieving gas-liquid separation through centrifugal force.

[0068] In this embodiment, the specific implementation of the gear pump structure is not limited. It can be set according to the specific application scenario, as long as it meets the ratio of the first number of teeth and the second number of teeth, and generates periodic volume expansion so that water vapor reaches the dew point temperature and condenses under adiabatic expansion.

[0069] Specifically, in the condensation drive module, the difference in the number of teeth between the first number of teeth of the driving gear 131 and the second number of teeth of the driven gear 132 is determined based on the difference between the volume expansion rate and the expansion rate threshold in a single meshing cycle, wherein the expansion rate threshold is determined by the power of the hydrogen internal combustion engine unit.

[0070] In implementation, the volume expansion rate is the dimensionless ratio of the maximum volume of the inlet chamber 111 at the end of the two gears meshing to the minimum volume at the beginning of the two gears meshing, and the difference between the two minimum volumes. The expansion rate threshold is the product of the condensation efficiency coefficient and the power of the hydrogen internal combustion engine unit, and the unit of the condensation efficiency coefficient is kW. -1 It was determined based on several historical test data, and the value range is 0.02kW. -1 ~0.05kW -1 Preferably, the condensing efficiency coefficient is 0.02kW. -1 .

[0071] The tooth number difference is calculated by multiplying the difference between the volume expansion rate and the expansion rate threshold by the tooth number difference adjustment coefficient. The tooth number difference adjustment coefficient is determined based on several historical test data and ranges from 8 to 12. Preferably, the tooth number difference adjustment coefficient is 10.

[0072] Understandably, in the gear design of the condensation drive module, the method for determining the tooth number difference between the driving gear 131 and the driven gear 132 is based on the principle of thermodynamic expansion and the power matching criterion. The core principle is that when the driving gear 131 with a smaller number of teeth meshes with the driven gear 132 with a larger number of teeth, the difference in tooth count will generate a periodic volume expansion effect. This volume expansion will create a local low-pressure area in the meshing zone, causing the gas in the inlet chamber 111 to expand adiabatically and its temperature to drop sharply, thus condensing water vapor. The specific value of the tooth number difference is determined by two key factors: first, the actual degree of volume expansion within a single meshing cycle, i.e., the drastic change in volume during gear rotation; and second, the minimum volume expansion threshold required to meet condensation needs. In implementation, the optimal tooth number difference is determined by calculating the difference between the actual volume expansion degree and the power requirement threshold. When the actual expansion degree exceeds the power requirement threshold, a positive tooth number difference is used to enhance the condensation effect; when the actual expansion degree is insufficient, the gear parameters need to be readjusted. For high-power hydrogen internal combustion engines, increasing the tooth difference enhances volume expansion to cope with larger exhaust flow and higher water vapor content; conversely, decreasing the tooth difference avoids energy loss caused by excessive expansion.

[0073] This invention ensures stable condensation efficiency under different operating conditions through power matching, thereby improving the water recovery rate; at the same time, it prevents the mechanical complexity and increased manufacturing costs caused by blindly increasing the difference in the number of teeth; and achieves efficient water-gas separation and energy recovery with zero external energy consumption.

[0074] The droplet separation module 2 includes a cavity coaxial with the condensation drive module, which is used to give the condensed droplets centrifugal acceleration and make them move along the inner wall;

[0075] In implementation, the coaxial cavity formed by the droplet separation module 2 is closely fitted with the outer diameter and both sides of the drive gear 131 and driven gear 132, forming several conveying cavities 14 with each tooth of the gear; after the water vapor in the exhaust gas is condensed, it is sucked into several conveying cavities 14 together with the remaining gas. Due to the movement of the gear, it gains centrifugal acceleration and moves along the inner wall. At the same time, it is conveyed to the outlet cavity 112 with the rotational movement of the drive gear 131 and driven gear 132; and due to the periodic volume reduction generated when the drive gear 131 and driven gear 132 mesh, it is squeezed out of the outlet cavity 112 and enters the air outlet 122.

[0076] The collection module is located outside the cavity of the droplet separation module 2 and connected to the outlet cavity 112 of the condensation drive module, for receiving and storing the condensate and other gases after centrifugal separation.

[0077] Please continue reading. Figure 3 and Figure 4 As shown, it is a logic diagram of obtaining the first excess air coefficient and the second excess air coefficient of the water-hydrogen-electric cogeneration internal combustion engine of the present invention, and a logic diagram of adjusting the hydrogen injection quantity of the water-hydrogen-electric cogeneration internal combustion engine of the present invention.

[0078] Specifically, the data processing unit determines whether the hydrogen-oxygen combustion ratio of the hydrogen internal combustion engine unit is in a hydrogen-rich or hydrogen-lean state based on whether the voltage change rate output by the second power generation unit, which is collected in real time by the monitoring unit, is within a stable range.

[0079] If the voltage change rate is within a stable range, the hydrogen-oxygen combustion ratio of the hydrogen internal combustion engine unit is determined to be in a hydrogen-rich state.

[0080] If the voltage change rate is not within the stable range, the hydrogen-oxygen combustion ratio of the hydrogen internal combustion engine unit is determined to be in a hydrogen-deficient state.

[0081] In implementation, the data processing unit continuously monitors the voltage fluctuation characteristics of the second power generation unit through a voltage sensor to determine the combustion state. First, it obtains real-time sampling data of the voltage change rate from the monitoring unit and compares it with a preset stable range. The stable range is calibrated through bench testing, and its boundary value is determined by the maximum allowable voltage fluctuation amplitude of the power generation unit at the rated speed of the hydrogen internal combustion engine. When the voltage change rate of 5 consecutive sampling cycles remains within the stable range, the hydrogen-oxygen combustion ratio is determined to be in a hydrogen-rich state. Conversely, if the voltage change rate of any 3 consecutive sampling cycles exceeds the boundary of the stable range, it is determined to be in a hydrogen-lean state. Finally, the combustion state is marked as a binary signal (0 represents hydrogen-rich / 1 represents hydrogen-lean) and output to the trusted decision unit, while triggering the state change record to be stored in non-volatile memory.

[0082] The physical meaning of the stable interval is the instantaneous rate of change of the output voltage of the second power generation unit, expressed as a percentage per second (% / s). It characterizes the severity of voltage fluctuations and is measured by sampling the output voltage value of the second power generation unit every 10ms and calculating the rate of change of voltage between adjacent sampling points. Preferably, the stable interval is set to [0.8% / s, 1.2% / s].

[0083] Understandably, the determination of the hydrogen-oxygen combustion ratio is based on the physical relationship between the combustion characteristics of hydrogen fuel and the transfer of mechanical energy: in a hydrogen-rich state, excess hydrogen makes the combustion process more continuous and stable, improves the smoothness of piston movement, drives the generator rotor to rotate at a constant speed, and suppresses output voltage fluctuations within a narrow range; while in a hydrogen-lean state, insufficient local mixture concentration leads to discontinuous combustion, and drastic changes in piston acceleration cause crankshaft torque pulsations. This mechanical energy fluctuation is converted into periodic voltage abrupt changes by the generator unit. The setting of the stable range is essentially a critical index for quantifying "combustion stability." When the voltage fluctuation amplitude is below this critical value, it indicates that the mechanical energy transfer is stable, corresponding to the hydrogen-rich complete combustion condition; when the fluctuation amplitude continues to exceed the standard, it reflects the instability of energy transfer caused by incomplete combustion, corresponding to the hydrogen-lean state that needs to be corrected.

[0084] Specifically, the confidence decision unit corrects the slope parameter of the basic pre-stored relationship curve based on the determination result of the hydrogen-oxygen combustion ratio obtained by the data processing unit, and obtains the corrected pre-stored relationship curve.

[0085] In implementation, the confidence decision unit dynamically adjusts the slope parameters of the pre-stored relationship curves based on the determination of the hydrogen-oxygen combustion ratio: when the data processing unit determines that the state is hydrogen-rich, the slope of the oxygen concentration-excess air coefficient curve is increased by 12%–15%, while the slope of the nitrogen oxide concentration-excess air coefficient curve is decreased by 8%–10%; when the state is determined to be hydrogen-lean, a reverse correction is performed, with the slope of the oxygen concentration-excess air coefficient curve decreasing by 10%–12% and the slope of the nitrogen oxide-excess air coefficient curve increasing by 15%–18%. The slope correction is triggered in real time by the binarized signal of the combustion state, forming an immediately effective corrected pre-stored relationship curve.

[0086] Understandably, combustion conditions directly affect the detection characteristics of exhaust components. In a hydrogen-rich environment, excess hydrogen dilutes the oxygen concentration, leading to a decrease in the sensitivity of the oxygen sensor. In this case, increasing the slope of the oxygen concentration-excess air coefficient curve can compensate for the loss of detection sensitivity. Simultaneously, a hydrogen-rich environment inhibits nitrogen oxide (NOx) formation, making the NOx concentration curve too flat; decreasing the slope can restore its resolution. In a hydrogen-lean environment, the opposite characteristics emerge—oxygen concentration detection sensitivity increases while NOx formation surges. By reversing the slope parameter, the two curves maintain optimal linearity within their respective sensitive ranges. This dynamic correction essentially compensates for the sensor characteristics based on combustion chemistry, avoiding distortion of the relationship curves caused by changes in mixture concentration.

[0087] Specifically, the confidence decision unit,

[0088] Based on the aforementioned exhaust oxygen concentration and modified pre-stored relationship curve, the first excess air coefficient is determined;

[0089] The second excess air coefficient is determined based on the relationship curve between the exhaust nitrogen oxide concentration and the corrected pre-stored data.

[0090] The preset error tolerance range is corrected based on the actual exhaust humidity, wherein the actual exhaust humidity is determined based on the condensate flow rate.

[0091] In implementation, the confidence decision unit first maps the real-time exhaust oxygen concentration value to the first excess air coefficient based on the modified pre-stored relationship curve, and simultaneously maps the nitrogen oxide concentration value to the second excess air coefficient. Those skilled in the art will understand that the mapping data table for mapping exhaust oxygen concentration value and nitrogen oxide concentration value to excess air coefficient is well known in the art and will not be described in detail here.

[0092] The confidence decision unit then calculates the actual humidity of the exhaust gas based on the condensate flow rate (unit: liters / minute) using a humidity conversion model. The humidity conversion model is established through calibration tests. Specifically, when the condensate flow rate is 5L / min to 8L / min, the corresponding humidity is 40% to 60%. Preferably, the linear proportionality coefficient between the condensate flow rate and the humidity is 7.5.

[0093] The confidence decision unit then scales the range of the preset error tolerance based on the actual humidity value. Specifically, for every 10% increase in humidity, the tolerance range expands by 0.02; for every 10% decrease in humidity, the tolerance range shrinks by 0.015.

[0094] Understandably, the actual humidity of exhaust gas is essentially a direct representation of the amount of water generated in the hydrogen-oxygen combustion reaction: when hydrogen and oxygen burn completely, approximately 9 kg of water vapor is produced per kilogram of hydrogen. This water vapor partially condenses into liquid water after entering the gas recovery unit through the exhaust system. There is a strict thermodynamic equilibrium relationship between the condensate flow rate and the content of uncondensed water vapor in the exhaust gas. An increase in the condensate flow rate indicates a higher total water vapor content in the exhaust gas, meaning a higher actual humidity. This humidity causes specific interference to gas composition detection: in high humidity environments, water vapor molecules occupy the exhaust gas volume, leading to a falsely low oxygen concentration reading (due to oxygen dilution), while simultaneously promoting the dissolution of nitrogen oxides into liquid water droplets, resulting in a falsely high NOx concentration reading. The mechanism of inferring actual humidity from the condensate flow rate essentially utilizes the water products of the combustion reaction as a natural tracer, based on the constant stoichiometric ratio of water generated during the complete combustion of hydrogen fuel. The logic of error tolerance correction lies in the fact that at high humidity (high condensate flow rate), the cross-interference between oxygen and NOx sensors intensifies, necessitating a wider tolerance range to accommodate measurement deviations; at low humidity, the interference weakens, allowing for a narrower tolerance to improve control accuracy.

[0095] This invention collects condensate generated by the hydrogen internal combustion engine through a gas recovery unit, and by monitoring the condensate flow rate, it achieves self-calibrating fault-tolerant control based on combustion chemical products, enabling the system to maintain reliable decision-making under variable load conditions.

[0096] Specifically, the confidence decision unit determines the weighted average of the first excess air coefficient and the second excess air coefficient as the actual excess air coefficient based on the comparison result that the deviation between the first excess air coefficient and the second excess air coefficient is within the corrected error tolerance range.

[0097] In implementation, the confidence decision unit executes a dual-coefficient arbitration logic. When the deviation between the first excess air coefficient (based on oxygen concentration) and the second excess air coefficient (based on nitrogen oxide concentration) is within the error tolerance range after humidity correction, the weighted average of the two is output, where the weight of the oxygen concentration coefficient is 0.6 and the weight of the nitrogen oxide concentration coefficient is 0.4.

[0098] Understandably, the dual-sensor weighted calculation improves accuracy by leveraging the complementarity of measurement errors. In the hydrogen-rich range, the oxygen sensor's reading is higher due to interference from unburned hydrogen, while in the hydrogen-deficient range, the NOx sensor's reading is lower due to thermal drift at high temperatures. The fixed weighting of 6:4 is based on the error distribution of the two types of sensors under typical operating conditions. Weighting reduces the overall error and prevents control instability caused by the failure of a single sensor.

[0099] Specifically, the confidence decision unit determines the corresponding actual excess air coefficient value based on the comparison result of the deviation exceeding the error tolerance range and the determination result of the hydrogen-oxygen combustion ratio.

[0100] In practice, when the deviation exceeds the tolerance range, the calculation is based on the rule of prioritizing the combustion state. If the hydrogen-oxygen combustion ratio is determined to be in a hydrogen-deficient state, the second excess air coefficient is used as the actual excess air coefficient; if it is determined to be in a hydrogen-rich state, the first excess air coefficient is used as the actual excess air coefficient.

[0101] Understandably, the combustion state priority rule during sensor conflict stems from the specific chemical reaction characteristics of hydrogen combustion. In a hydrogen-deficient state, the combustion temperature exceeds 1600℃, leading to a sharp increase in nitrogen oxide (NOx) formation. At this point, NOx concentration exhibits a strong linear relationship with the excess air coefficient, while the oxygen sensor is significantly affected by the water vapor dilution effect. In a hydrogen-rich state, the excess hydrogen makes the oxygen concentration detection value more sensitive, while the suppression of NOx formation causes its curve to flatten. Essentially, this rule is based on the dynamic switching of sensor reliability according to the combustion phase, and its physical basis lies in the differences in the chemical reaction pathways of hydrogen fuel within different excess air coefficient ranges.

[0102] Specifically, the fuel supply unit dynamically adjusts the hydrogen injection quantity based on the deviation between the actual excess air coefficient and the target value of the excess air coefficient, wherein...

[0103] If the hydrogen-oxygen combustion ratio is determined to be in a hydrogen-deficient state, then the reduction range of hydrogen injection quantity will be limited.

[0104] If the hydrogen-oxygen combustion ratio is determined to be in a hydrogen-rich state, then the upward adjustment of the hydrogen injection quantity will be limited.

[0105] In practice, the specific formula for calculating the adjustment amount of hydrogen injection is as follows:

[0106] ΔQ=k×(L0-L),

[0107] Wherein, ΔQ is the adjustment amount of hydrogen injection quantity, in grams per second (g / s); k is the adjustment coefficient, in grams per second (g / s), with a value range of 0.2 g / s to 0.4 g / s, preferably 0.3 g / s; L is the actual excess air coefficient, dimensionless; L0 is the target value of the excess air coefficient, with a value range of 1.8 to 3.0. Those skilled in the art can set the target value of the excess air coefficient according to the actual situation of the hydrogen internal combustion engine, which will not be elaborated here.

[0108] In practice, under hydrogen-deficient conditions, the injection volume is limited to a decrease of ≤15%; under hydrogen-rich conditions, the injection volume is limited to an increase of ≤10%.

[0109] Understandably, the constraint on fuel adjustment range is a safety mechanism to prevent exceeding the flammability limit. In a hydrogen-lean state, the excess air coefficient is already high. If the hydrogen injection rate is reduced too much, the excess air coefficient of the mixture in some areas may exceed the lean-burn limit, leading to misfire. In a hydrogen-rich state, excess hydrogen accumulates, and if the injection rate is increased too much, the combustion chamber temperature will rise sharply, causing pre-ignition or backfire. The setting of the 15% and 10% limits is directly related to the flammability range of hydrogen (4% to 75% volume concentration). A 15% reduction in injection rate corresponds to a decrease in mixture concentration of approximately 3.5 vol%, close to the lower flammability limit; a 10% increase corresponds to an increase in concentration of 2.2 vol%, approaching the knock critical point. This adjustment logic achieves safe control under varying operating conditions.

[0110] Specifically, the fuel supply unit adjusts the amount of hydrogen injected by adjusting the injection pulse width of the hydrogen fuel injection valve.

[0111] In implementation, the fuel supply unit precisely adjusts the hydrogen injection quantity by sending a pulse width modulation (PWM) signal to the hydrogen fuel injection valve. First, it queries a pre-stored pulse width-flow mapping table based on the required hydrogen injection quantity (in grams per second). This mapping table, established through flow calibration experiments, converts the injection quantity into the corresponding solenoid valve energizing time (in milliseconds). Then, a high-precision square wave signal is generated to drive the injection valve, where the high-level duration of the square wave is the actual injection pulse width, and the low-level duration is the valve body cooling interval. During energization, the valve core is lifted by electromagnetic force, opening the hydrogen passage and allowing fuel to be injected into the intake manifold at a preset pressure. After de-energization, the spring resets, cutting off the gas supply. The entire injection process is synchronized with the crankshaft rotation angle, ensuring that each injection is completed during the intake valve opening period.

[0112] Understandably, by precisely adjusting the supply of hydrogen fuel to precisely regulate the excess air coefficient, not only can pre-ignition and knocking caused by an overly rich mixture be avoided, thus improving engine stability, but also misfire caused by an overly lean mixture can be prevented, thereby improving combustion efficiency and reducing the formation of nitrogen oxides.

[0113] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A water-hydrogen-electric cogeneration internal combustion engine, characterized in that, include: A hydrogen internal combustion engine unit, used to burn hydrogen and air to generate power; The first power generation unit is connected to the output terminal of the hydrogen internal combustion engine unit to convert the mechanical energy generated by the hydrogen internal combustion engine unit into electrical energy. A gas recovery unit, which is connected to the exhaust end of the hydrogen internal combustion engine unit, is used to convert the pressure of the gas discharged from the hydrogen internal combustion engine unit into mechanical energy, and at the same time condense the water vapor in the discharged gas. The second power generation unit is connected to the gas recovery unit and converts the mechanical energy generated by the gas discharged from the hydrogen internal combustion engine unit into electrical energy. The monitoring unit is connected to the second power generation unit and the gas recovery unit respectively, and is used to collect the voltage change rate output by the second power generation unit and the exhaust oxygen concentration, exhaust nitrogen oxide concentration and condensate flow rate of the exhaust gas in the gas recovery unit in real time. A data processing unit, connected to the monitoring unit, is used to determine the hydrogen-oxygen combustion state of the hydrogen internal combustion engine unit based on the voltage change rate, and to obtain the actual exhaust humidity based on the condensate flow rate. The data processing unit determines whether the hydrogen-oxygen combustion ratio of the hydrogen internal combustion engine unit is in a hydrogen-rich or hydrogen-lean state based on whether the voltage change rate output by the second power generation unit, which is collected in real-time by the monitoring unit, is within a stable range. If the voltage change rate is within a stable range, the hydrogen-oxygen combustion ratio of the hydrogen internal combustion engine unit is determined to be in a hydrogen-rich state. If the voltage change rate is not within the stable range, the hydrogen-oxygen combustion ratio of the hydrogen internal combustion engine unit is determined to be in a hydrogen-deficient state. A confidence decision unit, connected to both the monitoring unit and the data processing unit, is used to calculate the excess air coefficient by comparing the exhaust oxygen concentration and the exhaust nitrogen oxide concentration, and output the actual excess air coefficient based on the error tolerance range corrected for the actual exhaust humidity. Specifically, the slope parameter of the basic pre-stored relationship curve is corrected based on the hydrogen-oxygen combustion ratio determination result obtained by the data processing unit to obtain a corrected pre-stored relationship curve. A first excess air coefficient is determined based on the exhaust oxygen concentration and the corrected pre-stored relationship curve. The second excess air coefficient is determined based on the relationship curve between the exhaust nitrogen oxide concentration and the corrected pre-stored data. The preset error tolerance range is corrected based on the actual exhaust humidity, wherein the actual exhaust humidity is determined based on the condensate flow rate; Based on the comparison results of the deviation between the first excess air coefficient and the second excess air coefficient being within the corrected error tolerance range, the weighted average of the first excess air coefficient and the second excess air coefficient is determined as the actual excess air coefficient. Based on the comparison results where the deviation exceeds the error tolerance range, the corresponding actual excess air coefficient value is determined according to the determination result of the hydrogen-oxygen combustion ratio. If the hydrogen-oxygen combustion ratio is determined to be in a hydrogen-deficient state, the second excess air coefficient is used as the actual excess air coefficient; if it is determined to be in a hydrogen-rich state, the first excess air coefficient is used as the actual excess air coefficient. A fuel supply unit, which is connected to the confidence decision unit and the hydrogen internal combustion engine unit respectively, is used to dynamically adjust the amount of hydrogen injected into the hydrogen internal combustion engine unit when hydrogen is input, based on the deviation between the actual excess air coefficient and the target value of the excess air coefficient.

2. The water-hydrogen-electric cogeneration internal combustion engine according to claim 1, characterized in that, The gas recovery unit includes: The condensation drive module has its air inlet connected to the exhaust end of the hydrogen internal combustion engine unit. It includes a rotatable drive gear with a first number of teeth and a driven gear with a second number of teeth. The drive gear is driven to rotate by the exhaust flow to cause periodic volume expansion of the meshing part through the difference in the number of teeth, forming a local low-pressure zone to condense water vapor. A droplet separation module includes a cavity coaxial with the condensation drive module, used to give condensed droplets centrifugal acceleration and allow them to move along the inner wall; A collection module, located outside the cavity of the droplet separation module, is used to receive and store the condensate after centrifugal separation; The number of teeth in the first case is less than the number of teeth in the second case.

3. The water-hydrogen-electric cogeneration internal combustion engine according to claim 2, characterized in that, In the condensation drive module, the difference in the number of teeth between the first number of teeth of the driving gear and the second number of teeth of the driven gear is determined based on the difference between the volume expansion rate and the expansion rate threshold in a single meshing cycle, wherein the expansion rate threshold is determined by the power of the hydrogen internal combustion engine unit.

4. The water-hydrogen-electric cogeneration internal combustion engine according to claim 3, characterized in that, The fuel supply unit dynamically adjusts the hydrogen injection quantity based on the deviation between the actual excess air coefficient and the target value of the excess air coefficient. If the hydrogen-oxygen combustion ratio is determined to be in a hydrogen-deficient state, then the reduction range of hydrogen injection quantity will be limited. If the hydrogen-oxygen combustion ratio is determined to be in a hydrogen-rich state, then the upward adjustment of the hydrogen injection quantity will be limited.

5. The water-hydrogen-electric cogeneration internal combustion engine according to claim 4, characterized in that, The fuel supply unit adjusts the hydrogen injection quantity by adjusting the injection pulse width of the hydrogen fuel injection valve.

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