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

Abstract

The controller 112 predicts backfire in the intake manifold (106) of the hydrogen engine of the vehicle. The intake manifold (106) comprises the hydrogen injector (108), and the hydrogen gas is injected via the hydrogen injector (108) and supplied to the engine cylinder (102) of the engine. The controller (112) is configured to detect hydrogen accumulation (104) using the hydrogen sensor (110) positioned in the intake manifold (106). The controller (112) is configured to compare the detected hydrogen accumulation (104) with the predetermined threshold and predict the probability of backfire occurrence in the intake manifold (106) based on the comparison. Upon predicting the probability of the backfire occurrence, the controller (112) takes control measures. These control measures avoid the hydrogen accumulation (104) in the intake manifold (106) and the probability of backfire occurrence reduces.

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 PREDICT 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 method to predict 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 an accumulation of the hydrogen and propagates into the intake manifold causing damage to the engine parts and deteriorate the engine performance. A prediction of backfire and its intensity in such scenarios is crucial and at present there is no such mechanism available using which prediction of the backfire occurrence 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 predict 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 prediction 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 to predict backfire in an intake manifold 106 of a hydrogen engine, according to an embodiment of the present invention. The intake manifold 106 comprises a hydrogen injector 108, wherein the hydrogen gas in injected via the hydrogen injector 108 and supplied to an engine cylinder 102 of the hydrogen engine, characterized in that, the controller 112 is configured to detect concentration / accumulation of hydrogen 104 using a hydrogen sensor 110 positioned in the intake manifold 106. The controller 112 is configured to compare the detected hydrogen accumulation 104 with a predetermined threshold. The controller 112 is configured to predict a probability of backfire occurrence in the intake manifold 106 based on the comparison. The predetermined threshold is the amount of accumulated hydrogen 104 in the intake manifold 106 for which backfire occurs in the intake manifold 106. If the concentration of hydrogen accumulation 104 is beyond the predetermined threshold, the controller 112 predicts the probability of the backfire occurrence.

[0008] According to the embodiment of the present invention, the hydrogen injector 108 is fixed to a port in the intake manifold 106, and the hydrogen sensor 110 is positioned upstream of the port in the intake manifold 106, and at a predetermined distance from the port. The predetermined distance varies with a design of the intake manifold 106 and accordingly the positioning of the hydrogensensor 110 changes. The hydrogen sensor 110 detects the hydrogen accumulation 104 and sends the data to the controller 112, referring which the controller 112 predicts the probability of the backfire occurrence.

[0009] According to the embodiment of the present invention, the controller 112 upon backfire prediction takes control measures. The control measures is at least one selected from a group of 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 is injected in the intake manifold 106 does not completely enters an engine combustion chamber before the intake valve closes or if the fuel is injected before the intake valve opens, there are chances of hydrogen accumulation 104 in the intake manifold 106 leading to the backfire occurrence. By controlling the opening or closing timing of the intake valve based on the feedback from the hydrogen sensor 110, hydrogen accumulation 104 is avoided. The ignition timing advance or retard the combustion to reduce the in-cylinder temperature, the source of ignition in case of backfire in hydrogen engine is the high temperature of the engine components, such as intake valve, spark plug, etc. Due to the hydrogen accumulation 104 and high temperature of these components, probability of backfire occurrence increase. Based on the input from the hydrogen sensor 110, 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 NOx emission. Lambda enhancement refers to increasing the quality of air in the air fuel ratio, which slows down the combustion process and 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 106 is a strategy in which water is injected into the intake manifold 106 which travels into the combustion chamber and absorbs theheat in the combustion chamber and reduces the in-cylinder temperature. These control measures avoid hydrogen accumulation 104 and probability of the backfire occurrence in the intake manifold 106 reduces and enhance the durability and robustness of the hydrogen engine.

[0011] According to the embodiment of the present invention, the controller 112 calculates the probability of the backfire occurrence based on a ratio of the determined hydrogen accumulation 104 and air in the intake manifold 106. The controller 112 deactivates the hydrogen injection and flushes out the accumulated hydrogen 106 based on the calculated probability, which reduces the probability of backfire occurrence.

[0012] According to an 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 accumulation hydrogen in the intake manifold 106 which reduces the probability of the occurrence of the backfire. For e.g., in the present scenario, once the hydrogen accumulation 104 is determined, the controller 112 shifts the injection angle and pauses the injection for few cycles until the accumulated hydrogen 104 flushes out. The start of injection angle or end of an injection angle is associated with the intake valve lift or exhaust valve lift. The intake and exhaust valves are electronically controlled valves.

[0013] In accordance with an embodiment of the present invention, the controller 112 is provided with necessary signal detection, acquisition, and processing circuits. The controller 112 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 orapplications or modules / models and / or threshold values / ranges, reference values, predefined / predetermined criteria / conditions, which is / are accessed by the at least one processor as per the defined routines. The internal components of the controller 112 are not explained for being state of the art, and the same must not be understood in a limiting manner. The controller 112 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 112 is implementable in the form of System-in-Package (SiP) or System-on-Chip (SOC) or any other known types. Examples of controller 112 comprises but not limited to, microcontroller, microprocessor, microcomputer, Electronic Control Units (ECUs), etc.

[0014] According to the embodiment of the present invention, a working of the controller 112 is envisaged. The controller 112 predicts the probability of backfire occurrence in the intake manifold 106 of the hydrogen engine of the vehicle. The hydrogen injector 108 fixed to a port in the intake manifold 106 and the hydrogen sensor 110 is positioned upstream of the port at the predetermined distance. The port is specifically designed to accommodate the hydrogen injector 108. The hydrogen sensor 110 determines the hydrogen accumulation 104 and sends signal to the controller 112. The controller 112 takes control measures, and the control measures are selected from the group comprising optimization of valve timing, optimization of fuel injection time, lambda enhancement, water injection, and the exhaust gas recirculation. These control measures mitigate the hydrogen accumulation 104 thus avoid the probability of the backfire occurrence.

[0015] Fig. 2 illustrates different stages performed throughout the process of predicting backfire in the intake manifold 106 of the hydrogen engine of the vehicle, according to the present invention. The intake manifold 106 comprises the hydrogen injector 108. The hydrogen gas is injected via the hydrogen injector 108 and supplied to the engine cylinder 102. The method comprises plurality of steps of which a step 202 comprises detecting, by the controller 112, the hydrogenaccumulation 104 using the hydrogen sensor 110 in the intake manifold 106. A step of 204 comprises comparing, by the controller 112, the detected hydrogen accumulation 104 with the predetermined threshold. A step of 206 comprises predicting, by the controller 112, the probability of backfire occurrence in the intake manifold 106 based on the comparison. The predetermined threshold is the amount of accumulated hydrogen 104 in the intake manifold 106 for which backfire occurs in the intake manifold 106 near the intake valve.

[0016] According to the method, the step of 204 comprises positioning of the hydrogen sensor 110. The hydrogen injector 108 is fixed to the port and the hydrogen sensor 110 is positioned upstream of the port in the intake manifold 106 and at the predetermined distance from the port. The hydrogen accumulation 104 continuously detected by the hydrogen sensor 110 and the detected signal is received by the controller 112. The method comprises predicting, by the controller 112, the probability of backfire occurrence through the hydrogen sensor 110 by comparing with the predetermined threshold. Upon prediction, the method comprises performing, by the controller 112, the control measures. The control measures is at least one selected from 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 accordingly. The control measures avoids / prevents the possibility of the backfire occurrence.

[0017] According to the method, the step of 206 comprises calculating the probability of the backfire occurrence based on the ratio of the determined hydrogen accumulation 104 and air in the intake manifold 106. Based on the calculated probability, the method comprises deactivating the injection, and flushing out the accumulated hydrogen 104. Once the accumulated hydrogen 104 is flushed out, the probability of the backfire occurrence reduces and the controller 112 starts the hydrogen injection for the next cycle. The flushing out corresponds to passing it to the engine in controlled manner.

[0018] According to the present invention, the controller 112 and the method to predict backfire occurrence in the intake manifold 106 of the hydrogen engine is disclosed. The controller 112 detects the hydrogen accumulation 104 in the intake manifold 106 using the hydrogen sensor 110 and based on comparison with the threshold, predicts the probability of the backfire occurrence. Based on the prediction, the controller 112 takes control measures and avoids chances of severe backfire and deterioration of different components. To account for the deterioration of different components, an adaptation logic is included in the controller 112. The adaptation logic generates additive correction factors (or control measures) to correct valve timing and using the correction factor, the controller 112 shifts the duration of the injector which is adapted for specific operating zone based on the feedback of the hydrogen sensor 110. Hence, predicting backfire occurrence provides a robust control system for backfire prediction which improves performance and durability of hydrogen fueled engine.

[0019] 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 (112) to predict backfire in an intake manifold (106) of a hydrogen engine, said intake manifold (106) comprises a hydrogen injector (108), wherein hydrogen gas is injected via said hydrogen injector (108) and supplied to an engine cylinder (102) of said engine, characterized in that, said controller (112) configured to: a. detect hydrogen accumulation (104) using a hydrogen sensor (110) positioned in said intake manifold (106); b. compare the detected hydrogen accumulation (104) with a predetermined threshold, and c. predict probability of backfire occurrence in said intake manifold (106) based on the comparison.

2. The controller (112) as claimed in claim 1, wherein said hydrogen injector (108) is fixed in a port in said intake manifold (106), and said hydrogen sensor (110) is positioned upstream of said port in said intake manifold (106) and at a predetermined distance from said port.

3. The controller (112) as claimed in claim 1 configured to perform control measures upon backfire prediction, wherein said control measures is at least one selected from a group comprising of optimizing valve timing, optimizing fuel injection time, lambda enhancement, water injection, and exhaust gas recirculation.

4. The controller (112) as claimed in claim 1 configured to: a. calculate probability of said backfire occurrence based on a ratio of the determined hydrogen accumulation (104) and air in said s (106), and b. deactivate said hydrogen injection and flush out said accumulated hydrogen (104) based on said calculated probability.

5. The controller (112) as claimed in claim 3, 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 for predicting backfire in an intake manifold (106) of a hydrogen engine, said intake manifold (106) comprises hydrogen injector (108), wherein a hydrogen gas is injected via said hydrogen injector (108) and supplied to an engine cylinder (102) of said engine, said method performed by a controller (112), characterized by, said method comprising the steps of: a. detecting hydrogen accumulation (104) using a hydrogen sensor (110) positioned in said intake manifold (106); b. comparing the detected hydrogen accumulation (104) with a predetermined threshold, and c. predicting probability of backfire occurrence in said intake manifold (106) based on the comparison.

7. The method as claimed in claim 6, wherein said hydrogen injector (108) is fixed to a port, and said hydrogen sensor (110) is positioned upstream of said port in said intake manifold (106) and at a predetermined distance from said port.

8. The method as claimed in claim 6, comprises performing control measures after predicting said probability backfire occurrence, said control measures is at least selected from a group of comprising optimizing valve timing, optimizing fuel injection time, lambda enhancement, water injection, and exhaust gas recirculation.

9. The method as claimed in claim 6 comprising the steps of: a. calculating said probability of said backfire occurrence based on a ratio of the determined hydrogen accumulation (104) and air in said intake manifold (106), andb. deactivating said injection and flushing out said accumulated hydrogen (104) based on the calculated probability.

10. The method as claimed in claim 8, wherein under optimizing fuel injection time, 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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