Control unit and method for determining a backfire in the intake manifold of a hydrogen engine

Abstract

Title: Control Unit and Method for Determining Backfire in the Intake Manifold of a Hydrogen Engine. The control unit 118 determines backfire in the intake manifold 110 of the vehicle's hydrogen engine. The intake manifold includes the hydrogen injector 112 and a pressure sensor 114. The hydrogen engine includes the knock sensor 106. Gaseous hydrogen is injected through the hydrogen injector 112 and sent to the engine cylinder. The control unit 118 is configured to detect the first signal indicating a hydrogen flame in the intake manifold 110 via the flame sensor 116. The control unit 118 measures the second and third signals via the pressure sensor 114 and the knock sensor 106, respectively.Control unit 118 validates and determines the presence of backfire based on the correlation of the first signal with the second and third signals. After determining backfire, control unit 118 takes control measures that reduce its occurrence. Figure 1 for the summary.

Description

Title of the invention: Control unit and method for determining a backfire in the intake manifold of a hydrogen engine technical field

[0001] The present invention relates to a control unit and a method for determining the backfire in an intake manifold of a hydrogen engine of a vehicle.

[0002] Background of the invention:

[0003] Gaseous hydrogen is a carbon-neutral fuel with a very high calorific value and ignites very quickly. In a vehicle's hydrogen engine, due to the use of hydrogen as fuel, backfire is a consequence of combustion. Backfire in the hydrogen engine causes a flame near a point, such as a spark plug or an intake valve, and propagates through the intake manifold, damaging engine parts and impairing engine performance. Detecting backfire and its intensity in such scenarios is crucial, and no such mechanism is currently available that would enable its detection.

[0004] According to prior document JP5321690, a method is described that prevents the production of backfire and / or afterburning by gradually increasing the flow velocity of residual gaseous fuel in an intake system and / or an exhaust system, and then starting a motor-by-motor control in a state where the gaseous fuel supply is interrupted in a motor-start operation. CONSTRUCTION: A hydrogen flow regulating valve and a closed-type solenoid valve are provided in a hydrogen supply line downstream of a pressure regulator, and a hydrogen injection valve is provided in hydrogen supply lines downstream of the latter for injecting gaseous hydrogen.When both hydrogen concentrations in an exhaust passage and in an intake passage are determined by hydrogen sensors to exceed a set value, a pump is actuated to open valves in gas passages and exhaust gas in a reservoir is gradually introduced into the exhaust and intake passages so that residual gaseous hydrogen is discharged in a mode of this kind, namely that the . The flow rate is gradually reduced. The solenoid valve is then opened for startup. This prevents backfires and / or afterburning.

[0005] The invention relates to a control unit for determining a backfire in an intake manifold of a hydrogen engine.

[0006] According to the invention, the intake manifold comprises a hydrogen injector and a pressure sensor, and said hydrogen engine comprises a knock sensor, into which gaseous hydrogen is injected via said hydrogen injector and sent to a cylinder of said engine, characterized in that said control unit is configured to: a. detect a first signal, indicating a hydrogen flame in said intake manifold via a flame sensor, b. measure a second signal and a third signal simultaneously using a pressure sensor and a knock sensor, respectively, and c. validate and determine the presence of a backfire based on a correlation between said first signal and said second signal and the third signal.

[0007] Preferably: - said flame sensor is positioned between said hydrogen injector and an intake valve, - said flame sensor detects the hydrogen flame, the wavelength of which is within a predetermined range, - the control unit is configured to perform control measures after determination of said backfire, said control measures being at least one chosen from a group including valve control optimization, fuel injection timing optimization, lambda increase, water injection and exhaust gas recirculation, - said optimization of fuel injection time includes a shift of at least one angle at the start of the injection and of one angle at the end of an injection accordingly.

[0008] The invention also relates to a method for determining backfire in an intake manifold of a hydrogen engine, said intake manifold comprising a hydrogen injector and a pressure sensor, and said hydrogen engine comprising a knock sensor, into which gaseous hydrogen is injected via said hydrogen injector and sent to a cylinder of said engine, characterized in that said method comprises the following stages: a. detection of a first signal, indicating a hydrogen flame (108) in said intake manifold (110) by means of a flame sensor (116), b. measurement of a second signal and a third signal simultaneously by a pressure sensor (114) and by the knock sensor (106), respectively, and c. validation and determination of the presence of a backfire based on a correlation between said first signal and said second signal and said third signal.

[0009] Preferably: - the flame sensor is positioned between the hydrogen injector and an intake valve. - A hydrogen flame is detected via the flame sensor, the wavelength of which is within a predetermined range. - the process includes performing control measures after determining said backfire, said control measures being at least one chosen from a group including optimization of valve control, optimization of fuel injection time, increase of lambda, water injection and recirculation of exhaust gas, - under optimization of the fuel injection control, the process includes shifting an injection start angle or an injection end angle accordingly.

[0010] Brief description of the attached drawings:

[0011] An embodiment of the invention is described with reference to the following accompanying drawings:

[0012] Figure 1 illustrates a functional diagram of a control unit for determining backfire in an intake manifold of a hydrogen engine of a vehicle according to an embodiment of the present invention and

[0013] Fig. 2 illustrates various stages carried out in the operation of determining backfire in the intake manifold of the hydrogen engine of the vehicle according to the present invention.

[0014] Detailed description of embodiments:

[0015] Figure 1 is a block diagram of a control unit 118 for determining backfire in an intake manifold 110 of a hydrogen engine according to an embodiment of the present invention. The intake manifold 110 includes a hydrogen injector 112 and a pressure sensor 114. The engine The hydrogen control unit includes a knock sensor 106. Gaseous hydrogen is injected through the hydrogen injector 112 and sent to a cylinder 104 of the hydrogen engine. The control unit 118 is characterized in that it is configured to detect a first signal indicating a hydrogen flame 108 in the intake manifold 110 via a flame sensor 116. The control unit 118 is configured to measure a second and a third signal simultaneously. The first signal is measured via a pressure sensor 114, and the second signal is measured by the knock sensor 106. The control unit 118 is configured to validate and determine the presence of backfire by correlating the first signal with the second and third signals. When backfire occurs, the pressure in the intake manifold and the knocking in the engine increase.The 114 pressure sensor and the 106 knock sensor are already fitted in the vehicle. The 114 pressure sensor is also known as the manifold air pressure (MAP) sensor.

[0016] According to one embodiment of the present invention, the flame sensor 116 is positioned between the hydrogen injector 112 and an intake valve 102. The flame manifold 116 detects the hydrogen flame 108 and its intensity, the wavelength of which varies within a predetermined range. In one exemplary embodiment, the predetermined wavelength range is from 220 nm to 700 nm. By placing the flame sensor 116 in the intake manifold 110 near the intake valve, it detects the flames as soon as the backfire occurs and generates the first signal. By comparing the first signal to the second and third signals, the control unit 118 confirms the occurrence of the backfire. After detecting and confirming the occurrence of the backfire, the control unit 118 takes control measures.There is a change in the second and third signals due to the presence / appearance of the flashback. Thus, the control unit 118 validates the appearance of the flashback using the first, second, and third signals.

[0017] According to the embodiment of the present invention, the control unit 118 takes control measures after backfire detection. The control measures are at least one selected from the group consisting of optimizing valve control, optimizing fuel injection timing, increasing lambda, water injection, and exhaust gas recirculation.

[0018] Each of the control measures is explained below. Valve control is a key factor in preventing backfires. If fuel injected into the intake manifold 110 does not completely enter an engine combustion chamber before the intake valve closes, or if fuel is injected before the intake valve opens, backfires may occur. Fuel accumulation in the intake manifold 110 causes backfire. By controlling the intake valve opening or closing rate based on the response from the flame sensor 116, hydrogen accumulation is prevented, thus reducing the likelihood of backfire. The fuel ignition timing advances or retards combustion, which changes the cylinder temperature. This is because the ignition source in the case of backfire is at a high temperature, as are engine components such as the intake valve, spark plug, etc. Based on the input from the flame sensor 116, sufficient ignition timing is retarded to control and maintain a temperature below the hydrogen auto-ignition temperature. The lambda augmentation strategy is used to control the cylinder temperature and NOx emissions.Increasing the lambda value refers to improving the air-fuel ratio, which slows down the combustion process and the propagation of the hydrogen flame. Slowing down the combustion process helps lower the rate of heat release in the combustion chamber, thus reducing the cylinder temperature. Water injection into the intake manifold (110) is a strategy in which water is injected into the intake manifold (110), where it passes into the combustion chamber, absorbs heat, and reduces the cylinder temperature.

[0019] According to the embodiment of the present invention, optimizing the fuel injection timing includes shifting the injection angle by at least one angle at the beginning and one angle at the end of the injection accordingly to prevent backfire in the subsequent engine cycle. Based on the presence of backfire, the control unit 118 determines the shift in the injection angle. Thus, for example, in the present scenario, once backfire is detected, the control unit 118 pauses injection for a few cycles until the backfire is under control. By controlling the opening of either the intake or exhaust valve, the fuel injection cycle into the engine cylinder is controlled. The intake and exhaust valves are electronically controlled.

[0020] According to one embodiment of the present invention, the control unit 118 is provided with the necessary circuits for signal detection, acquisition, and processing. The control unit 118 is a unit comprising an input interface, output interfaces having pins or access points, a memory element such as random access memory (RAM) and / or read-only memory (ROM), an analog-to-digital converter (ADC), and a digital converter. to analog (DAC), clocks, timers, counters, and at least one processor (capable of implementing machine learning) connected to each other and to other components via communication bus channels. The memory element (not shown) is pre-loaded with logic and instructions or programs of applications or modules or models and / or values / threshold ranges, reference values, predefined / predetermined criteria / conditions, lists, knowledge sources, which are accessed by the at least one processor, as well as by defined routines. The internal components of the control unit 118 are not explained further as they are part of the prior art and cannot be considered exhaustive.The 118 control unit can also include communication units such as transmitters and receivers for wireless or wired communication, such as Global System for Mobile Communications (GSM), 3G, 4G, 5G, Wi-Fi, Bluetooth, Ethernet, serial networks, etc. The 118 control unit can be implemented as a system-in-a-package (SiP), a system-on-a-chip (SoC), or any other known type. Examples of a 118 control unit include, but are not limited to, microcontrollers, microprocessors, microcomputers, electronic control units (ECUs), etc.

[0021] According to the embodiment of the present invention, the operation of the control unit 118 is described below. The control unit 118 determines the backfire in the intake manifold 110 of the vehicle's hydrogen engine. The flame sensor 116 is positioned between the hydrogen injector 112 and the intake valve 102, and the control unit 118 receives a signal from the flame sensor 116. The flame sensor 116 detects the hydrogen flame 108 and sends the signal to the control unit 118. The pressure sensor 114 is mounted in the intake manifold 110, and the knock sensor 106 is mounted in the hydrogen engine. The control unit 118 receives a signal from these sensors and confirms the occurrence of the backfire.After validation, the control unit 118 takes control measures, which are chosen from a group including valve control optimization, fuel injection timing optimization, lambda increase, water injection, and exhaust gas recirculation. These control measures reduce the occurrence of backfire.

[0022] Figure 2 illustrates various stages carried out in the operation of determining the backfire in the intake manifold 110 of the hydrogen engine of the vehicle according to the present invention. The intake manifold 110 includes the hydrogen injector 112 and the pressure sensor 114. The hydrogen engine The process includes the knock sensor 106, and hydrogen gas is injected via the hydrogen injector 112 and sent to the engine cylinder. The method comprises a plurality of stages, among which stage 202 includes detecting, by the control unit 118, the first signal indicating the hydrogen flame 108 in the intake manifold 110 via the flame sensor 116. Stage 204 includes measuring, by the control unit 118, the second and third signals simultaneously, via the pressure sensor and the knock sensor 106, respectively. Stage 206 includes validating and determining, by the control unit 118, the presence of backfire by correlating the first signal with the second and third signals.

[0023] According to this method, step 204 comprises positioning the flame sensor 116 between the hydrogen injector 112 and the intake valve 102. Once the backfire has occurred, the flame sensor 116 detects the hydrogen flame 108 and sends a signal to the control unit 118. The method includes detecting the hydrogen flame 108 via the flame sensor 116, the wavelength of which is within a predetermined range. The control unit 118 confirms the presence of the backfire by referring to the signals from the pressure sensor 114 and the knock sensor 106. After confirmation, the method includes taking control measures via the control unit 118. The control measures are at least one chosen from the group including valve control optimization, fuel injection timing optimization, lambda increase, water injection and exhaust gas recirculation.Furthermore, by optimizing the fuel injection timing, the process includes a corresponding offset of at least one angle at the start of injection and one angle at the end of injection. Control measures prevent the possibility of backfire. Validation also prevents any false detection of backfire.

[0024] The present invention describes the control unit 118 and the method for determining backfire in the intake manifold 110 of the hydrogen engine. The control unit 118 determines the backfire and, based on this determination, the control unit 118 takes control measures. These control measures prevent any possibility of severe backfire and damage to various components. Over time, wear and breakage of engine components can occur, and together with the manufacturing tolerances of the various components of the hydrogen fuel system, there would be a tendency for backfire events to increase. To account for the wear and breakage of various components, adaptive logic is included in the control unit 118. The adaptive logic creates factors of Additional corrections are made to adjust the valve control, and using the correction factor, the control unit 118 shifts the operating time of the hydrogen injector 112, which is specific to particular operating ranges based on the hydrogen sensor's response. Having a strategy for determining backfire and correcting backfire control parameters thus provides a robust control system for backfire detection and diagnostics, which improves the performance and longevity of a hydrogen-powered engine.

[0025] It is understood that the embodiments explained in the above description are merely illustrative and do not limit the scope of the invention. Many of these embodiments and other modifications and changes to the embodiment explained in the description are envisaged.

Claims

Demands

1. A control unit (118) for determining a backfire in an intake manifold (110) of a hydrogen engine, said intake manifold (110) comprising a hydrogen injector (112) and a pressure sensor (114) and said hydrogen engine comprising a knock sensor (106), into which gaseous hydrogen is injected via said hydrogen injector (112) and sent to a cylinder (104) of said engine, characterized in that said control unit (118) is configured to: a. detect a first signal, indicating a hydrogen flame (108) in said intake manifold (110) via a flame sensor (116), b. measure a second signal and a third signal simultaneously by a pressure sensor (114) and by the knock sensor (106), respectively, and c.validate and determine the presence of a backfire based on a correlation between said first signal and said second signal and said third signal.

2. A control unit (118) as claimed in claim 1, wherein said flame sensor (116) is in position between said hydrogen injector (112) and an intake valve (102).

3. A control unit (118) as claimed in claim 1 or 2, wherein said flame sensor (116) detects the hydrogen flame (108), a wavelength of which is in a predetermined range.

4. The control unit (118) according to any one of the preceding claims, configured to perform control measures after determination of said backfire, said control measures being at least one selected from a group including optimization of valve control, optimization of fuel injection time, increase of lambda, water injection and exhaust gas recirculation.

5. The control unit (118) according to claim 4, wherein said fuel injection timing optimization comprises a offset of at least one of an angle at the beginning of the injection and of an angle at the end of the injection accordingly.

6. A method for determining backfire in an intake manifold (110) of a hydrogen engine, said intake manifold (110) comprising a hydrogen injector (112) and a pressure sensor (114) and said hydrogen engine comprising a knock sensor (106), into which gaseous hydrogen is injected via said hydrogen injector (112) and sent to a cylinder (104) of said engine, characterized in that said method comprises the stages of: a. detecting a first signal, indicating a hydrogen flame (108) in said intake manifold (110) via a flame sensor (116), b. measuring a second signal and a third signal simultaneously by a pressure sensor (114) and by the knock sensor (106), respectively, and c.validation and determination of the presence of a backfire based on a correlation between said first signal and said second signal and said third signal.

7. The method as claimed in claim 6, wherein the flame sensor (116) is in position between the hydrogen injector (112) and an intake valve (102).

8. The method as claimed in claim 6 or 7 comprises detecting a hydrogen flame (108) by means of the flame sensor (116), the wavelength of which is in a predetermined range.

9. The method as claimed in any one of claims 6 to 8 comprises performing control measures after determining said backfire, said control measures being at least one selected from a group comprising optimization of valve control, optimization of fuel injection time, increase of lambda, water injection and exhaust gas recirculation.

10. The method as claimed in claim 9, wherein under optimization of the fuel injection control, the method comprises shifting an injection start angle or an injection end angle accordingly.

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