A controller and method to determine backfire in an intake manifold of a hydrogen engine

Abstract

The controller (118) determines backfire in the intake manifold (110) of the hydrogen engine of the vehicle. The intake manifold (110) comprises the hydrogen injector (112) and a pressure sensor 114. The hydrogen engine comprise the knock sensor (106). The hydrogen gas is injected via the hydrogen injector (112) and supplied to the engine cylinder of the engine and the controller (118) is configured to detects the first signal which indicates the hydrogen flame in the intake manifold (110) through the flame sensor (116). The controller (118) measures the second signal and the third signal through the pressure sensor (114) and the knock sensor (106), respectively. The controller (118) validates and determines presence of the backfire based on correlation of the first signal with the second signal and the third signal. Upon backfire determination, the controller (118) takes control measures which mitigates the backfire occurrence.

Description

FORM 2THE PATENTS ACT, 1970(39 of 1970) & The Patents Rules 2003COMPLETE SPECIFICATION(SECTION 10 and Rule 13)1. Title of the invention:A CONTROLLER AND METHOD TO DETERMINE BACKFIRE IN AN INTAKE MANIFOLD OF A HYDROGEN ENGINE2. Applicants: a. Name: Bosch Global Software Technologies Private Limited Nationality: INDIAAddress: 123, Industrial Layout, Hosur Road, Koramangala, Bangalore - 560095, Karnataka, India b. Name: Robert Bosch GmbHNationality: GERMANYAddress: Postfach 300220, 0-70442, Stuttgart, GermanyComplete Specification:The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.Field of the invention:

[0001] The present invention relates to a controller and a method to determine backfire in an intake manifold of a hydrogen engine of a vehicle.Background of the invention:

[0002] Hydrogen Gas is a carbon neutral fuel with very high calorific value and catches fire very fast. In a hydrogen engine of a vehicle, due to use of hydrogen as a fuel, backfire is a burning issue. The backfire in the hydrogen engine initiates with a flame near the spot such as spark plug or intake valve and propagates into the intake manifold causing damage to the engine parts and deteriorate the engine performance. A detection of backfire and its intensity in such scenarios is crucial and at present there is no such mechanism available using which detection is possible.

[0003] According to a prior art JP5321690, a method for preventing generation of backfire and / or afterburn by increasing flow speed of residual gaseous fuel in an intake system and / or an exhaust system gradually, and then starting an engine-by- engine cranking in a condition where supply of the gaseous fuel is disconnected in engine starting operation. CONSTITUTION: Hydrogen flow regulation valves, and a closed type of 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 it to inject hydrogen gas. When both hydrogen concentrations in an exhaust passage and an intake passage by hydrogen sensors are determined to exceed a set value, a pump is actuated to open valves in gas passages and exhaust gas in a tank is gradually introduced into the exhaust passage and the intake passage, so residual hydrogen gas is discharged in such a mode that its flow speed is gradually increased. The solenoid valve is then opened for starting. Backfire and / or afterburn is thus prevented.Brief description of the accompanying drawings:

[0004] An embodiment of the disclosure is described with reference to the following accompanying drawings.

[0005] Fig. 1 illustrates a block diagram of a controller to determine backfire in an intake manifold of a hydrogen engine of a vehicle, according to an embodiment of the present invention, and

[0006] Fig. 2 illustrates different stages performed throughout the process in the determination of backfire in the intake manifold of the hydrogen engine of the vehicle, according to the present invention.Detailed description of the embodiments:

[0007] Fig. 1 illustrates a block diagram of a controller 118 to determine backfire in an intake manifold 110 of a hydrogen engine, according to an embodiment of the present invention. The intake manifold 110 comprises a hydrogen injector 112 and a pressure sensor 114. The hydrogen engine comprises a knock sensor 106. The hydrogen gas is injected via the hydrogen injector 112 and supplied to an engine cylinder 104 of the hydrogen engine, characterized in that, the controller 118 is configured to detect a first signal, indicating a hydrogen flame 108 in the intake manifold 110, thorough a flame sensor 116. The controller 118 is configured to measure a second signal and a third signal at the same time. The first signal is measured through a pressure sensor 114 and the second signal is measured through the knock sensor 106. The controller 118 is configured to validate and determine presence of the backfire by correlating the first signal with the second signal and the third signal. During the backfire occurrence, intake manifold pressure and knocking in the engine increases. The pressure sensor 114 and the knock sensor 106 are already installed in the vehicle. The pressure sensor 114 is also known as Manifold Air Pressure (MAP) sensor.

[0008] According to an embodiment of the present invention, the flame sensor 116 is positioned between the hydrogen injector 112 and an intake valve 102. The flame sensor 116 detects the hydrogen flame 108 and its intensity whose wavelength liesin a predetermined range. In an exemplary embodiment, the predetermined range of the wavelength is 220 nm to 700 nm. Positioning the flame sensor 116 in the intake manifold 110 near the intake valve detects the flames as soon as the backfire occurs and generates the first signal. Comparing the first signal with the second signals and the third signal, the controller 118 validates the occurrence of the backfire. Upon detection and validation of the backfire occurrence, the controller 118 takes control measures. There is a change in the second signal and the third signal due to presence / occurrence in backfire. Thus, the controller 118 validates the occurrence of the backfire using the first signal, the second signal and the third signal.

[0009] According to the embodiment of the present invention, the controller 118 upon backfire detection takes control measures. The control measures is at least one selected from a group comprising optimization of valve timing, optimization of fuel injection time, lambda enhancement, water injection, and exhaust gas recirculation.

[0010] Each of the control measures is explained. The valve timing is a key factor leading to the backfire. If a fuel injected in the intake manifold 110 does not completely enters into an engine combustion chamber before the intake valve closes or if the fuel is injected before the intake valve opens, there are chances of fuel accumulation in the intake manifold 110, leading to the backfire. By controlling the opening or closing timing of the intake valve based on the feedback from the flame sensor 116, accumulation of the hydrogen is avoided which reduces the probability / possibility of backfire occurrence. The fuel ignition timing advances or retards the combustion which changes the in-cylinder temperature, as the source of ignition in case of backfire is the high temperature of the engine components, such as intake valve, spark plug, etc., Based on the input from the flame sensor 116, sufficient ignition retard is done in the ignition timing to control and keep the temperature lower than a self-ignition temperature of hydrogen. Lambda enhancement strategy is used in controlling in cylinder temperature and a NOx emission. Lambda enhancement refers to increasing the quality of air in the air fuelratio, which slows down the combustion process and the hydrogen flame propagation. The slowing down of the combustion process helps in lowering the heat release rate in the combustion chamber which reduces the in-cylinder temperature. Water injection into the intake manifold 110 is a strategy in which water is injected into the intake manifold 110 which travels into the combustion chamber and absorbs the heat in the combustion chamber and reduces the incylinder temperature.

[0011] According to the embodiment of the present invention, the optimization of fuel injection time comprises shift of at least one of a start of injection angle or end of an injection angle accordingly to avoid the event of the backfire in the next engine cycle. Based on the backfire presence, the controller 118 determines the shifting of the injection angle. For e.g., in the present scenario, once the backfire is determined, the controller 118 pause the injection for few cycles, until the backfire is under control. By controlling a lift of the intake valve or an exhaust valve, the cycle of the injection of the fuel in the engine cylinder is controlled. The intake and exhaust valves are electronically controlled valves.

[0012] In accordance with an embodiment of the present invention, the controller 118 is provided with necessary signal detection, acquisition, and processing circuits. The controller 118 is the one which comprises input interface, output interfaces having pins or ports, the memory element such as Random Access Memory (RAM) and / or Read Only Memory (ROM), Analog-to-Digital Converter (ADC) and a Digital-to-Analog Convertor (DAC), clocks, timers, counters and at least one processor (capable of implementing machine learning) connected with each other and to other components through communication bus channels. The memory element (not shown) is pre-stored with logics or instructions or programs or applications or modules / models and / or threshold values / ranges, reference values, predefined / predetermined criteria / conditions, lists, knowledge sources which is / are accessed by the at least one processor as per the defined routines. The internal components of the controller 118 are not explained for being state of the art, andthe same must not be understood in a limiting manner. The controller 118 may also comprise communication units such as transceivers to communicate through wireless or wired means such as Global System for Mobile Communications (GSM), 3G, 4G, 5G, Wi-Fi, Bluetooth, Ethernet, serial networks, and the like. The controller 118 is implementable in the form of System- in-Package (SiP) or System- on-Chip (SOC) or any other known types. Examples of controller 118 comprises but not limited to, microcontroller, microprocessor, microcomputer, Electronic Control Units (ECUs), etc.

[0013] According to the embodiment of the present invention, a working of the controller 118 is envisaged. The controller 118 determines the backfire in the intake manifold 110 of the hydrogen engine of the vehicle. The flame sensor 116 is positioned between the hydrogen injector 112 and the intake valve 102 and the controller 118 receives signal from the flame sensor 116. The flame sensor 116 detects the hydrogen flame 108 and sends the signal to the controller 118. The pressure sensor 114 is installed in the intake manifold 110 and the knock sensor 106 is installed in the hydrogen engine, the controller 118 receives signal from these sensors and validates the occurrence of the backfire. Upon validation, the controller 118 takes control measures which are selected from a group of the optimizing valve timing, the optimizing fuel injection time, the lambda enhancement, the water injection, and the exhaust gas recirculation, etc., These control measures mitigate the backfire occurrence.

[0014] Fig. 2 illustrates different stages performed throughout the process of determining backfire in the intake manifold 110 of the hydrogen engine of the vehicle, according to the present invention. The intake manifold 110 comprises the hydrogen injector 112 and the pressure sensor 114. The hydrogen engine comprises the knock sensor 106 and the hydrogen gas is injected via the hydrogen injector 112 and supplied to the engine cylinder. The method comprises plurality of steps of which a step 202 comprises detecting, by the controller 118, the first signal indicating the hydrogen flame 108 in the intake manifold 110 through the flamesensor 116. A step of 204 comprises measuring, by the controller 118, the second signal and the third signal at the same time, through the pressure sensor 114 and the knock sensor 106 respectively. A step of 206 comprises validating and determining, by the controller 118, the presence of the backfire by corelating the first signal with the second and the third signal.

[0015] According to the method, the step of 204 comprises positioning of the flame sensor 116 between the hydrogen injector 112 and the intake valve 102. Once the backfire takes place, the flame sensor 116 captures the hydrogen flame 108 and sends signal to the controller 118. The method comprises detecting hydrogen flame 108 through the flame sensor 116 whose wavelength lies in predetermined range. The controller 118 validates the presence of the backfire by referring the signals from the pressure sensor 114 and the knock sensor 106. Upon validation, the method comprises performing, by the controller 118, control measures . The control measures is at least one selected form the group comprising, optimizing valve timing, optimizing fuel injection time, lambda enhancement, water injection, and exhaust gas recirculation. Further, under optimizing fuel injection timing, the method comprises shifting the start of injection or the end of injection angle accordingly. The control measures avoid / prevents the possibility of the backfire occurrence. The validation also avoids any backfire misdetection.

[0016] According to the present invention, the controller 118 and method to determine backfire in the intake manifold 110 of the hydrogen engine is disclosed. The controller 118 determines the backfire and based on the determination, the controller 118 takes control measures. These control measures avoid chances of severe backfire and deterioration of different components. With time, there is wear and tear of the engine components and along with the manufacturing tolerance of different components in the hydrogen fuel supply system there would be a tendency of increase of backfire events. To account for the wear and tear of different components, an adaptation logic is included in the controller 118. The adaptation logic generates additive correction factors to correct valve timing and using thecorrection factor, the controller 118 shifts the duration of the hydrogen injector 112 which is adapted for specific operating zone based on the feedback of the hydrogen sensor. Hence, having a strategy for determining backfire and correct the backfire control parameters provides a robust control system for backfire detection and diagnosis which improves performance and durability of hydrogen fueled engine.

[0017] It should be understood that the embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modification and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.

Claims

We claim:

1. A controller (118) to determine backfire in an intake manifold (110) of a hydrogen engine, said intake manifold (110) comprises a hydrogen injector (112) and a pressure sensor (114), and said hydrogen engine comprise a knock sensor (106) wherein a hydrogen gas is injected via said hydrogen injector (112) and supplied to an engine cylinder (104) of said engine, characterized in that said controller (118) configured to: a. detect a first signal, indicating a hydrogen flame (108) in said intake manifold (110), through a flame sensor (116). b. measure a second signal and a third signal at the same time, through a pressure sensor (114) and the knock sensor (106), respectively, and c. validate and determine presence of backfire based on correlation between said first signal and said second signal and said third signal.

2. The controller (118) as claimed in claim 1, wherein said flame sensor (116) is positioned between said hydrogen injector (112) and an intake valve (102).

3. The controller (118) as claimed in claim 1, wherein said flame sensor (116) detects the hydrogen flame (108) whose wavelength lies in predetermined range.

4. The controller (118) as claimed in claim 1 configured to perform control measures upon determination of said backfire, wherein said control measures is at least one selected from a group comprising optimization of valve timing, optimization of fuel injection time, lambda enhancement, water injection, and exhaust gas recirculation.

5. The controller ( 118) as claimed in claim 4, wherein said optimization of fuel injection time comprises shift of at least one of a start of injection angle and an end of injection angle accordingly.

6. A method of determining backfire in an intake manifold (110) of a hydrogen engine, said intake manifold (110) comprises a hydrogen injector (112) and a pressure sensor (114), and said hydrogen engine comprises knock sensor (106) wherein a hydrogen gas in injected via said hydrogen injector (112) and supplied to an engine cylinder (104) of said engine, characterized by, said method comprising the steps of: a. detecting a first signal, indicating a hydrogen flame (108) in said intake manifold (110), through a flame sensor (116). b. measuring a second signal and a third signal at the same time, through a pressure sensor (114) and a knock sensor (106) respectively, and c. validating and determining presence of backfire by correlating said first signal with said second signal and said third signal.

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

8. The method as claimed in claim 6 comprises detecting hydrogen flame (108) through said flame sensor (116) whose wavelength lies in predetermined range.

9. The method as claimed in claim 6 comprises performing control measures after determining the backfire and said control measures is at least one selected form a group comprising, optimizing valve timing, optimizing fuel injection time, lambda enhancement, water injection, and exhaust gas recirculation.

10. The method as claimed in claim 9, wherein under optimizing fuel injection timing, said method comprises shifting a start of injection or an end of injection angle accordingly.Dated 30 August 2024 (Digitally signed)Siddharth Karkhanis (IN / PA- 1195)On-behalf of the Applicant

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