Method and processing device for controlling permission to start engine

Abstract

There is provided a method (500) for controlling permission to start an engine (101), where the engine is configured to provide gaseous fuel by a gaseous fuel system (200) comprising:-one or more controllable valves (211) arranged to provide fuel to at least one regulator (230) at an upstream pressure (P2); -said at least one regulator (230) arranged to regulate the upstream pressure (P2) of the fuel down to a lower working pressure (P3); -a low pressure valve (260), which is arranged downstream of the at least one regulator (230); and-at least one working pressure sensor (280) arranged at the engine (101). The method (500) comprises:-closing (s540) the low pressure valve (260); -controlling (s542) at least one of the one or more controllable valves (211) such that the gaseous fuel system (200) is pressurized upstream of the low pressure valve (260); -opening (s544) the low pressure valve (260); -monitoring (s546) an increase (AP3) of the working pressure by using the at least one working pressure sensor (280) after opening (s544) the low pressure valve (260); and-controlling (s548) the permission to start the engine (101) on the basis of the monitored increase (AP3) in working pressure.

Description

Technical Field

[0001] The present invention relates to safety measures related to gaseous fuel powered engines and, in particular, to a method and processing means for controlling permission to start a gaseous fuel powered engine. The invention also relates to a computer program and a computer readable medium implementing the method according to the invention. Background Art

[0002] The following background description constitutes a description of the background to the present invention and, however, does not necessarily constitute prior art.

[0003] The engine can be driven by a gaseous fuel, such as methane gas fuel or hydrogen fuel. Such gaseous fuels may include compressed natural gas (CNG) fuel, liquefied natural gas (LNG) fuel and / or liquefied gasoline (LPG) fuel, etc. The engine is provided with gas through a gas fuel system. Therefore, the gas fuel system may include one or more fuel tanks, multiple valves, pipes / hoses, pressure sensors, filters and injectors arranged to provide gaseous fuel to the cylinders of the engine. The gas fuel system also includes at least one regulator, which is arranged to adjust the higher storage or upstream pressure of the gas fuel downward to a lower operating pressure suitable for the capabilities of the components downstream of the at least one regulator. Due to space limitations in vehicles driven by gas fuel, for example, the fuel in the fuel tank is stored at a high storage pressure to reduce the volume of the fuel, thereby also reducing the volume of the fuel tank. Therefore, the function of at least one regulator is to reduce the higher storage or upstream pressure to a suitable downstream operating pressure so that downstream components can work effectively without being damaged by the high pressure. Summary of the Invention

[0004] Regulators in gaseous fuel systems typically include an actuator that moves within the regulator body, for example due to the operating pressure of the gaseous fuel and a reaction force generated by some kind of regulator spring arrangement. Consequently, in certain situations, such as when the regulator is in the open position, the surfaces of the moving actuator and the inner regulator body can come into contact with each other. If one or more of these surfaces becomes contaminated, for example coated with oil or grease, these surfaces may stick together due to the vacuum created when they come into contact with each other. These surfaces will then be difficult to separate, and the regulator may become stuck in the open position. A situation in which this problem may occur is when the gaseous fuel system has been drained during maintenance, whereby the regulator is completely open. Another possible situation in which this may occur is when the fuel tank is almost empty, i.e. when the storage pressure is low, and the engine is running at a very high load. When this problem occurs, the regulator is therefore stuck in the open position and cannot regulate the pressure.

[0005] The adjuster may also become stuck in the open position if it is damaged, for example if its adjuster spring assembly is damaged.

[0006] If a cranking attempt is made while the regulator is stuck open, there is a considerable risk of damaging one or more components downstream of the regulator. These downstream components, such as filters, injectors, and / or pipes / hoses, are designed to cope with the lower operating pressures typically provided by the regulator. However, if cranking is initiated while the regulator is stuck in its open position, all valves between the gas fuel tank and the engine are open, which causes the downstream operating pressure to quickly become very high due to the stuck-open regulator, potentially rapidly rising to a level corresponding to the storage pressure in the gas fuel tank. Consequently, downstream components designed for relatively low operating pressures are then exposed to rapidly increasing and also very high pressures, at a level corresponding to the storage pressure used to store gas in the fuel tank.

[0007] Therefore, there is a considerable risk that downstream components may burst or be damaged in another way due to exposure to high pressure. Such component bursting or damage may result in off-road time for the vehicle and hearing loss and / or other injuries to the vehicle's driver or technicians working on the vehicle.

[0008] It would be advantageous to implement methods and processing devices that overcome or at least mitigate at least some of the above-mentioned disadvantages. In particular, it would be desirable to implement methods and processing devices that reduce damage and / or improve safety. To better address one or more of these problems, methods, processing devices, computer programs, computer-readable media, and carriers are provided having the features defined in the independent claims.

[0009] According to an aspect of the present invention, this object is achieved by the above method for controlling permission to start an engine, wherein the engine is configured to be supplied with gaseous fuel by a gaseous fuel system. The gaseous fuel system comprises:

[0010] - one or more fuel tanks configured to store fuel at a storage pressure;

[0011] - one or more controllable valves, each arranged downstream of the one or more fuel tanks to provide fuel at an upstream pressure to at least one regulator;

[0012] - said at least one regulator, said at least one regulator being arranged downstream of said one or more controllable valves for regulating the upstream pressure of the fuel downwards to a lower operating pressure;

[0013] - a low-pressure valve arranged downstream of the at least one regulator;

[0014] - one or more components arranged downstream of the low-pressure valve to provide fuel to the engine at the operating pressure; and

[0015] - at least one operating pressure sensor arranged at the engine;

[0016] The method comprises the following steps:

[0017] - closing the low-pressure valve;

[0018] - controlling at least one of the one or more controllable valves such that the gaseous fuel system is pressurized upstream of the low-pressure valve;

[0019] - Open the low-pressure valve;

[0020] - monitoring an increase in the operating pressure after opening the low-pressure valve by using the at least one operating pressure sensor; and

[0021] - controlling permission to start the engine based on a monitored increase in operating pressure.

[0022] This aspect of the present invention is advantageous in that it prevents damage and explosion to downstream low-pressure components caused by a faulty regulator. Thus, by adding the step of controlling the permission to start the engine, the gaseous fuel system can be monitored before the engine is allowed to start. When the engine is not allowed to start, one or more valves in the system remain closed, preventing high-pressure gas from flowing from the high-pressure circuit to low-pressure components in the low-pressure circuit. This prevents the high-pressure gas from exploding or damaging downstream components, including, for example, injectors, filters, and / or pipes / hoses.

[0023] Thus, the functionality of the regulator is tested before allowing or disallowing the engine to start. If the regulator appears to be malfunctioning, engine start-up may be disallowed / disallowed, minimizing the risk of damage to downstream components. Furthermore, this test may indicate whether one or more components used for the aforementioned test (e.g., the pressure sensor and / or the pressure reducing valve) other than the regulator itself are damaged or malfunctioning.

[0024] For example, the present invention can be used for maintenance when the gaseous fuel system has been drained. Draining the gaseous fuel system can cause the regulator to become stuck in its open position, potentially leading to rupture and / or other damage to low-pressure components. However, if the method according to the present invention is performed before starting the engine, the risk of such rupture and / or other damage is significantly reduced. Consequently, the vehicle's off-road time and the risk of hearing loss and / or other injuries to the driver or technician are significantly reduced.

[0025] According to an example, controlling permission to crank the engine may include or consist of: disallowing or permitting cranking of the engine. In the context disclosed herein, cranking the engine means initiating rotation of the crankshaft, for example, by using a starter motor. Therefore, ignition is not included in the term cranking and may be enabled or disabled during cranking. Typically, when starting an engine, the ignition system is enabled while the engine is cranking so that the gaseous fuel in the cylinders is ignited by a spark. However, cranking the engine may be performed with the ignition system disabled, whereby the gaseous fuel is not ignited and the engine is not started.

[0026] According to an example, the pressure reducing valve can be arranged downstream of at least one regulator. The pressure reducing valve can be arranged downstream of at least one regulator, either as part of the regulator or separate from the regulator. According to an example, the pressure reducing valve can be arranged upstream of the low-pressure valve. The pressure reducing valve can be arranged upstream of the low-pressure valve and downstream of at least one upstream pressure sensor. The pressure reducing valve can be arranged upstream of the low-pressure valve and downstream of at least one regulator. This means that the low-pressure valve can be arranged downstream of at least one regulator and the pressure reducing valve.

[0027] According to an embodiment of the present invention, if the monitored increase in operating pressure is higher than a first operating pressure increase threshold, the method comprises the following steps:

[0028] - Close the low pressure valve.

[0029] As a result, the risk of bursting and / or other damage to low-pressure components is significantly reduced, thereby minimizing the vehicle's off-road time and the risk of hearing damage and / or other injury to the driver or technician.

[0030] According to an embodiment of the present invention, the method comprises the following steps:

[0031] - opening one or more injectors arranged to inject fuel into the engine.

[0032] This step may be performed after the step of closing the low-pressure valve.

[0033] Thus, the overpressure in the gaseous fuel system is reduced, ie by cutting off the supply of gaseous fuel from the high-pressure circuit and releasing the gaseous fuel through the engine, ie through the air inlet manifold of the engine.

[0034] According to an embodiment of the present invention, the method further comprises one or more steps in the following group:

[0035] - closing the one or more controllable valves;

[0036] -activate regulator fault code;

[0037] - disabling the ignition system and initiating cranking of said engine; and

[0038] - controlling the engine to operate in a special mode in which the air intake of the engine and the gas volume in the cylinders of the engine are replaced by air while the ignition system is disabled.

[0039] By performing one or more of these actions, gaseous fuel is safely vented and / or pumped out of the gaseous fuel system without being ignited in the cylinders, causing pressure in the gaseous fuel system to decrease. Furthermore, a driver, technician, and / or another system may be made aware that a regulator and / or other gaseous fuel system component is experiencing a problem by activating a regulator fault code, which may include fault codes for other components as well.

[0040] These one or more actions may be performed after the step of opening one or more injectors arranged to inject fuel into the engine.

[0041] According to an embodiment of the present invention, if the monitored increase in operating pressure is higher than a first operating pressure increase threshold, then:

[0042] - controlling permission to crank the engine includes not allowing cranking of the engine when the ignition system is activated.

[0043] Thus, the risk of bursting and / or other damage to low-pressure components is significantly reduced.

[0044] According to an aspect of the invention, controlling permission to crank the engine includes allowing cranking of the engine if the monitored increase in operating pressure is below a second operating pressure increase threshold.

[0045] Therefore, if the pressure monitoring described above has indicated a stable pressure, and if the monitored increase in operating pressure is permissible, i.e., below the second operating pressure increase threshold, it is concluded that the regulator is functioning as it should. The engine can then be safely allowed to start up without risk of damage to downstream components.

[0046] According to an embodiment of the present invention, the gas fuel system comprises a pressure reducing valve arranged to release fuel from the gas fuel system at a set pressure. Between the step of controlling at least one of the one or more controllable valves so that the gas fuel system is pressurized upstream of the low-pressure valve and the step of opening the low-pressure valve, the method further comprises the following steps:

[0047] - closing the one or more controllable valves;

[0048] - monitoring the stability of said upstream pressure by using said at least one upstream pressure sensor; and

[0049] - controlling permission to start the engine based on the monitored stability.

[0050] In this document, the stability of pressure is defined as the deviation of pressure relative to the pressure level. If the deviation is less than a certain value during a predetermined time period, for example, less than 1 bar during a time period in the range of 5 seconds to 1 minute, or less than 0.5 bar during a time period in the range of 5 seconds to 1 minute, the pressure is monitored / detected / determined to be stable. The time period may be, for example, 10 seconds. Thus, if the pressure does not decrease by more than a certain value (e.g., 1 bar) during the time period, the pressure is monitored / detected / determined to be stable, and if the deviation is greater than the value during the time period, the pressure is monitored / detected / determined to be unstable.

[0051] An advantage of this embodiment is that damage and explosion of downstream low-pressure components caused by a faulty regulator can be avoided by monitoring the stability of upstream pressure. Thus, the regulator's functionality is tested before allowing or disallowing an engine start. If the regulator appears to be faulty, engine start-up may be disallowed / prohibited, minimizing the risk of damage to downstream components.

[0052] According to an example, at least one regulator may include a plurality of regulating stages. Thus, at least one regulator may include a multi-stage regulator, such as a two-stage regulator, a three-stage regulator, etc. This means that at least one regulator may gradually regulate the upstream pressure downward to a lower operating pressure. This may be advantageous in order to provide a more consistent and accurate operating pressure of the fuel, regardless of variations in the upstream pressure entering the at least one regulator. According to a specific example, a gas fuel system as disclosed herein may include at least one pressure reducing valve and at least one regulator including a plurality of regulating stages, wherein the at least one pressure reducing valve may be arranged on the downstream side of a corresponding regulating stage of the at least one regulator. A gas fuel system as disclosed herein may include a plurality of pressure reducing valves and at least one regulator including a plurality of regulating stages, wherein each pressure reducing valve may be arranged on the downstream side of each regulating stage of the at least one regulator. Thus, according to an example, a pressure reducing valve may be included in at least one regulator.

[0053] According to an embodiment of the present invention, if the upstream pressure is stable, the method further comprises the following steps:

[0054] - controlling the upstream pressure to be reduced to the set pressure of the pressure reducing valve;

[0055] - monitoring the stability of the upstream pressure as it decreases to the set pressure by using the at least one upstream pressure sensor; and

[0056] - controlling permission to start the engine based on the monitored stability.

[0057] Therefore, detect whether the pressure reducing valve is leaking and / or releasing gaseous fuel from the gaseous fuel system, that is, whether the regulator and / or the pressure reducing valve is damaged or faulty. If this is the case, the start-up of the engine may not be allowed to avoid damage to downstream components.

[0058] According to an embodiment of the present invention, if the upstream pressure is stable at the set pressure, the method further comprises the following steps:

[0059] - controlling at least one of the one or more controllable valves to open so that the gaseous fuel system downstream of the one or more controllable valves and upstream of the low-pressure valve is filled with fuel;

[0060] - monitoring the stability of said upstream pressure after filling by using said at least one upstream pressure sensor; and

[0061] - controlling permission to start the engine based on the monitored stability.

[0062] If the upstream pressure is stable, this may mean that the regulator has recovered, which can be determined after further testing. However, if the upstream pressure is unstable here, it can be concluded that the regulator has failed and the engine may not be allowed to start to avoid damage to downstream components.

[0063] According to an embodiment of the present invention, if monitoring indicates that the upstream pressure is unstable, then:

[0064] - controlling permission to crank the engine includes not allowing cranking of the engine.

[0065] By not allowing the engine to be started at unstable upstream pressures, the risk of explosion or other damage to downstream components due to a faulty regulator is significantly reduced.

[0066] According to an embodiment of the present invention, if the monitoring indicates that the upstream pressure is unstable, the method further comprises at least one step from the following group:

[0067] -determining that a regulator fault exists; and

[0068] -Activate regulator fault code.

[0069] The aforementioned regulator faults and / or regulator fault codes may relate to at least one regulator disposed downstream of one or more controllable valves regulating the upstream pressure of the fuel downward to a lower operating pressure, as disclosed herein.

[0070] By determining that a regulator fault exists and / or activating a fault code, the driver and / or technician or any other system is alerted of the regulator fault, thereby significantly reducing the risk of the driver, technician, and / or other systems causing a hazardous situation.

[0071] According to an embodiment of the invention, if monitoring indicates that the upstream pressure is stable after filling, then:

[0072] - controlling the permission to crank up said engine comprises a step of proceeding to a step of opening a low-pressure valve.

[0073] Therefore, a thorough test of the regulator is performed in multiple steps to ensure that the regulator is functioning properly before allowing the engine to be started.

[0074] According to aspects of the invention, the monitored increase in operating pressure and one or more of the first operating pressure increase threshold and the second operating pressure increase threshold comprise one of the following group:

[0075] - absolute value;

[0076] - derivative values; and

[0077] - Indicates a value that changes over time.

[0078] Depending on the characteristics of the gaseous fuel system and / or the current test situation, a suitable value for increasing the operating pressure and a corresponding threshold value may be selected to optimize the control of the permission to crank the engine.

[0079] According to an embodiment of the present invention, the method further comprises the following steps: if one or more initial conditions in the following group are met:

[0080] - the at least one operating pressure sensor detects that the operating pressure is lower than a first operating pressure threshold, and the vehicle including the gas fuel system is stopped;

[0081] - the at least one operating pressure sensor detects that the operating pressure is higher than a second operating pressure threshold and the vehicle including the gas fuel system is stopped; and

[0082] - a fault code indicating that the operating pressure has exceeded a third threshold has been activated, and fuel filling has been performed;

[0083] - then the method is allowed to be executed.

[0084] Permitting the method to be executed may also be referred to as allowing the method to be executed or started. Executing / starting / permitting the method for controlling the permission to start the engine when one or more initial conditions are met limits the method to only being run when truly necessary. This avoids the driver having to wait for the method to be executed every time the engine is started, while allowing the method to be run when necessary for safety reasons.

[0085] According to aspects of the present invention, the method is performed in combination with one of the following group:

[0086] -maintain;

[0087] - Workshop inspections; and

[0088] - When the storage pressure is below a storage pressure threshold and the engine fuel consumption is above a consumption threshold.

[0089] As a result, the safety of the technician and / or driver during maintenance and / or in the workshop is greatly improved. In addition, the risk of damage to downstream components in connection with high engine loads and / or gas fuel consumption when the tank level is low is reduced. A high fuel consumption above a consumption threshold may indicate that choking has occurred in the regulator, which means that the regulator is fully open so that the regulator acts as an orifice, wherein the mass flow is effectively limited to an upper limit value and cannot be increased further. When an attempt is made to consume fuel in excess of this upper limit, i.e. when the flow is choked by the regulator, the operating pressure P3 drops sharply. The consumption threshold associated with choking can here be one of a plurality of consumption thresholds, each of which is mapped to a specific storage pressure and an additional temperature. For lower storage pressures, the fuel consumption is generally lower.

[0090] According to an aspect of the present invention, a processing device is provided for controlling permission to start an engine. The engine is configured to be supplied with gaseous fuel by a gaseous fuel system.

[0091] The gas fuel system comprises:

[0092] - one or more fuel tanks arranged to store fuel at storage pressure;

[0093] - one or more controllable valves, each arranged downstream of the one or more fuel tanks to provide fuel at an upstream pressure to at least one regulator;

[0094] - said at least one regulator, said at least one regulator being arranged downstream of said one or more controllable valves for regulating the upstream pressure of the fuel downwards to a lower operating pressure;

[0095] - a low-pressure valve arranged downstream of the at least one regulator;

[0096] - one or more components arranged downstream of the low-pressure valve to provide fuel to the engine at the operating pressure; and

[0097] - at least one operating pressure sensor arranged at the engine;

[0098] The processing device is configured to perform the following steps:

[0099] - closing the low-pressure valve;

[0100] - controlling at least one of the one or more controllable valves such that the gaseous fuel system is pressurized upstream of the low-pressure valve;

[0101] - Open the low-pressure valve;

[0102] - monitoring the increase in the working pressure after opening the low-pressure valve by using the at least one working pressure sensor; and

[0103] - controlling the cranking of the engine based on the monitored increase in operating pressure.

[0104] It should be understood that all embodiments described with respect to the method aspects of the present invention are also applicable to the processing device aspects of the present invention. Therefore, all embodiments described with respect to the method aspects of the present invention can be performed by at least one processing device, which can also be a control unit or control device, i.e., a device. The processing device and its embodiments have advantages corresponding to those described above with respect to the method and its embodiments.

[0105] According to an aspect of the present invention, a carrier is provided. The carrier comprises:

[0106] -engine;

[0107] a gaseous fuel system configured to provide fuel to the engine; and

[0108] -A processing device as described herein.

[0109] According to aspects of the present invention, the above-mentioned computer program and computer-readable medium are configured to implement the method and embodiments thereof described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0110] Embodiments of the present invention will now be illustrated in more detail with reference to the accompanying drawings, in which like reference numerals are used for like components, and in which:

[0111] Figure 1 schematically illustrates an exemplary vehicle in which embodiments of the present invention may be implemented,

[0112] Figure 2 Schematically illustrates a gas fuel system in which embodiments of the present invention may be implemented,

[0113] Figure 3 An exemplary regulator is schematically shown,

[0114] Figure 4 An exemplary pressure reducing valve is schematically shown,

[0115] Figure 5 shows a flow chart of a method according to some aspects and / or embodiments of the present invention,

[0116] Figure 6 shows a flow chart of a method according to some aspects and / or embodiments of the present invention,

[0117] Figure 7 A control unit is shown in which a method according to any of the embodiments described herein may be implemented. DETAILED DESCRIPTION

[0118] Figure 1 An exemplary vehicle 100 is schematically shown, such as a truck, bus, car or another suitable vehicle, which will be used to explain the present invention. However, the present invention is not limited to vehicles such as Figure 1 The invention is not intended for use in the vehicle shown, but may also be used in substantially any vehicle, such as a rail vehicle or a water vehicle. The invention may also be used in stationary motors or working machines driven by gaseous fuel.

[0119] Figure 1 The vehicle 100 shown schematically in the figure includes an engine 101, which may include a combustion engine, such as an engine that consumes a gaseous fuel (such as methane fuel or hydrogen fuel) to generate torque for driving the vehicle. The engine can be an engine that operates according to the Otto cycle, in which an electric spark or, for example, a small amount of diesel ignites a fuel and air mixture in the engine cylinder. Essentially, the engine 101 in this document may include any device that converts chemical energy into mechanical energy and uses a gaseous fuel for its combustion / energy conversion. The engine then provides energy to the powertrain in the form of torque, or electrical energy. The exhaust gases generated by the engine 101 can be cleaned by an exhaust treatment system 150. The vehicle 100 may also include one or more other engines and / or machines, such as an electric motor.

[0120] The engine 101 can be connected to the gearbox 103 in a conventional manner, for example, via an output shaft 102 of the engine 101, which is connected to the gearbox 103 via a clutch 106 and an input shaft. An output shaft 107 (also called a propeller shaft) from the gearbox 103 can drive drive wheels 110, 111 via a final gear 108 (e.g., a conventional differential gear) and drive shafts 104, 105 connected to the final gear 108.

[0121] A gaseous fuel system 200 comprising at least one fuel tank 210 storing fuel at a storage pressure P1 is arranged to provide fuel to the engine 101. The gaseous fuel supply system 200 is described in more detail below.

[0122] The control unit / system 140 is Figure 1 1 and 2. The control unit / system 140 is schematically shown as receiving signals from and / or providing control signals to the engine 101 and / or the gas fuel system 200. The control unit / system 140 may also receive control signals from and / or provide control signals to other devices / components within the vehicle 100 or devices 170 external to the vehicle 101 via the communication unit 160. The control unit / system 140 may correspond to or include the processing device 145 described herein. The control unit / system / processing device 140 / 145 may include the control entities 602, 608, 610, 612, 614, 616, 618, 620, 622, 624, 631, 632, 633, 640, 642, 644, 646, 648, 651, 632, 633, 651, 652, 653, 654, 655, 656, 657, 658 and 661 mentioned below. Figure 1 The vehicle 100 may of course comprise a large number of devices / arrangements / units. However, Figure 1 In the figures, only the units / devices / entities useful for understanding the carrier of the present invention are shown.

[0123] Figure 2 An example of a gas fuel system 200 is schematically shown, which is configured to provide fuel to the engine 101, i.e., the cylinders of the engine 101, which will be used to explain the aspects and embodiments described herein. The gas fuel system 200 may include a high pressure circuit 201 and a low pressure circuit 202. It should be noted that although the boundary between the high pressure circuit 201 and the low pressure circuit 202 is Figure 2200, but this boundary can be adjusted to other locations in the gas fuel system 200. In general, the extensions of the high-pressure circuit 201 and the low-pressure circuit 202 can each follow the component pressure ratings rather than the nominal pressure in the system 200. For example, if the regulator 230 described below is stuck open and the low-pressure valve 260 described below is closed, the boundary between the high-pressure circuit 201 and the low-pressure circuit 202 moves to the low-pressure valve 260.

[0124] The gas fuel system 200 includes one or more fuel tanks 210 arranged to store fuel at a storage pressure P1. The fuel tanks 210 can be filled via a tank filling device 213. One or more controllable valves 211 are respectively arranged downstream of the one or more fuel tanks 210, for example, one valve 211 at each fuel tank 210, to provide fuel at an upstream pressure P2 to at least one downstream regulator 230, or to cut off the fuel supply from the fuel tanks 210 to the at least one regulator.

[0125] One or more controllable valves 211 may be electronically actuated valves that are typically controlled to open during cranking of engine 101 (i.e., while the starter motor is cranking engine 101). Gaseous fuel system 200 may include at least one manual valve 212 that may be easily accessible, for example, by a technician during service / maintenance. Such an easily accessible manual valve is particularly useful when fuel tank 210 and controllable valve 211 are more difficult to access. For example, in some vehicles, such as buses, fuel tank 210 is mounted on the roof of the vehicle.

[0126] During repair / maintenance, such as during a shop inspection, when the gas fuel system 200 needs to be depressurized / emptied, manual valve 212 and / or controllable valve 211 are closed, and the engine 101 is operated until the engine stops. Only a small amount of fuel remains in the gas fuel system 200, i.e., in the pipes / hoses and other components of the system. The gas fuel system 200 may also include an analog pressure sensor 220 near the manual valve 212, which can indicate the pressure to a technician, for example, in conjunction with the opening or closing of the manual valve 212.

[0127] The gas fuel system 200 may also include at least one regulator 230, arranged downstream of the one or more controllable valves 211 and, if applicable, the analog pressure sensor 220, to regulate the upstream pressure P2 of the fuel to a lower operating pressure P3. Thus, the function of the at least one regulator 230 is to reduce the upstream pressure P2 to the operating pressure P3 of the one or more injectors 270. The at least one regulator 230 may be arranged as a single regulator or as two or more regulators connected in parallel. The function of the regulator is explained in detail below.

[0128] The gas fuel system 200 further includes a pressure reducing valve 240, which is arranged to PRV The fuel is released from the gas fuel system 200. The pressure reducing valve 240 may be arranged to be included in the at least one regulator 230, or may be arranged as a separate component downstream of the at least one regulator 230. The pressure reducing valve 240 is explained in detail below.

[0129] The gas fuel system 200 also includes at least one upstream pressure sensor 250, which can be arranged at the at least one regulator 230, or can be arranged separately from the at least one regulator 230, for example, arranged at a pipe / hose or arranged at another component upstream of the regulator 230, to measure the upstream pressure P2 at the at least one regulator 230 or upstream of the regulator 230.

[0130] It should be noted that although the pressure reducing valve 240 and at least one upstream pressure sensor 250 are shown as included Figure 2 In the regulator 230 , however, as described above, the pressure reducing valve 240 and / or the at least one upstream pressure sensor 250 may be arranged separately from the regulator 230 .

[0131] Gaseous fuel system 200 also includes components downstream of at least one regulator 230 to provide fuel to engine 101 at an operating pressure P3. These components may include, for example, one or more injectors 290 disposed at engine 101 for injecting fuel into the cylinders of engine 101. These components may also include one or more filters 270 disposed upstream of the one or more injectors 290, as injectors 290 are particularly sensitive to dirt and oil. Alternatively, one or more high-pressure filters may be disposed upstream of at least one regulator 230, thereby eliminating the one or more filters 270 downstream of the regulator. Components downstream of at least one regulator 230 are selected / designed to align with the injector's operating pressure P3. To facilitate leak detection in gaseous fuel system 200, an electronically controlled low-pressure valve 260 (also referred to as a low-pressure shutoff valve) is positioned downstream of at least one regulator 230 and upstream of the components. When closed, low-pressure valve 260 allows the gas volume in gaseous fuel system 200 to be divided into two parts. The downstream components may also include pipes / hoses arranged to deliver the gaseous fuel.

[0132] Gaseous fuel system 200 also includes at least one operating pressure sensor 280, located at or at least adjacent to engine 101 and / or the injectors, for detecting operating pressure P3 at engine 101. Thus, at least one pressure sensor 250, 280 is located in each portion of the gas volume. These pressure sensors 250, 280 can monitor each portion of the gas volume for sudden pressure drops, which could indicate a broken pipe or similar damage. Additionally, pressure sensors 250, 280 can be used to monitor for slower pressure drops during engine shutdown, which could indicate the presence of a small leak in system 200.

[0133] The one or more controllable valves 211 and the low pressure valve 260 are initially controlled to be closed when ignition is on, but are then controlled to be open when the engine 101 is cranked up so that gaseous fuel is provided to the engine during cranking.

[0134] Figure 2 Also schematically shown is a control unit / system / processing device 140 / 145 configured to receive signals from and / or provide control signals to one or more components 211, 212, 220, 230, 240, 250, 260, 270, 280, 290 of the engine 101 and / or the gas fuel system 200. It should be noted that the control unit / system / processing device 140 / 145 may be configured to receive signals from and / or provide control signals to each of the one or more controllable valves 211, although this is not shown for readability reasons. Figure 2 Shown in.

[0135] Figure 3 A cross section of a regulator 230 such as that useful in a gas fuel system 200 is schematically shown. Note that Figure 3 An example of a simple regulator is shown for the purpose of explaining the aspects and embodiments presented herein. As will be appreciated by those skilled in the art, the solutions described herein can be implemented in systems including more complex regulators. As described above, the regulator 230 is arranged to regulate the upstream pressure P2 of the fuel at the inlet 231 of the regulator downward to a lower operating pressure P3 at the outlet 232 of the regulator. Thus, the function of the regulator 230 is to reduce the upstream pressure P2 downward to a downstream operating pressure P3.

[0136] Regulator 230 is a commonly used component in gas systems, where a higher feed pressure is regulated down to a lower pressure. Due to the functional requirements of downstream components for a lower specific gas pressure, a lower pressure downstream of regulator 230 may be required. Furthermore, regulator 230 can be used to regulate fluctuating higher feed pressures to a stable lower gas pressure. The regulator can utilize the principle that a regulator spring assembly 236 is offset by a lower gas pressure P3 acting on a surface 238. The regulator can also be actuated in one or more steps using an intermediate pressure and / or electronically controlled by a magnetic spool to control the opening of the orifice described below. Furthermore, some regulators may include multiple regulating stages, such as a mechanical stage followed by an electronic stage. The electronic regulating stage can then additionally function as a low-pressure valve. Thus, according to an example, low-pressure valve 260 may include or consist of an electronic regulating stage included in at least one regulator 230.

[0137] Gas regulators are used in gaseous fuel systems, such as methane or hydrogen. For example, in a compressed natural gas (CNG) fuel system, fuel is typically stored in its fuel tank at a storage pressure P1 ranging from 20 to 200 bar, and in some systems, up to 250 bar. This high pressure is then used to feed the fuel to the engine 101. The regulator 230 in the gaseous fuel system converts the high upstream pressure P2 generated by the high storage pressure P1 into an operating pressure P3, typically ranging from 6 to 9 bar, for which the injector is designed. For example, in a liquefied natural gas (LNG) fuel system, gas is stored in its fuel tank at a storage pressure P1 ranging from 8 to 16 bar. Due to the different pressures and volumetric flows, the regulator design differs for CNG and LNG fuel systems.

[0138] When no flow through the regulator 230 occurs and the reaction force of the regulator spring device 236 and the lower working pressure P3 acting on the surface 238 completely match each other, the regulator poppet valve 233 is closed against its seat 234, i.e. the open orifice between the regulator poppet valve 233 and its seat 234 is closed. When the downstream lower working pressure P3 decreases from this equilibrium state, the regulator spring device 236 will exert a force greater than the reaction force of the working pressure P3 acting on the surface 238. As a result, the poppet valve 233 moves away from its seat 234, causing the poppet valve 233 to move to the open position. In this open position of the poppet valve 233, filling / refilling of the downstream gas volume occurs and the downstream working pressure P3 increases again. Therefore, the regulator 230 always seeks to maintain equilibrium. If flow through the regulator occurs, the poppet valve 233 will move to a position where equilibrium is achieved again. The surface 238 on which the downstream working pressure P3 acts may be included in the regulator actuator 235 in the form of a diaphragm or piston, as Figure 3234 . In some cases, upstream pressure P2 and / or operating pressure P3 further act on the poppet valve to correspondingly open and close the open orifice between the regulator poppet valve 233 and its seat 234. Furthermore, the engine air inlet pressure can be fed back to the volume of the regulator spring device 236, thereby acting to open the open orifice.

[0139] When upstream pressure P2 decreases, the density of the upstream gas volume also decreases, which in turn means that for a given fuel demand, i.e., for the weight / amount of fuel required per time unit (e.g., in kilograms), the volume flow through poppet valve 233 will increase. As regulator 230 strives to achieve equilibrium, poppet valve 233 is then forced to open further, thereby allowing a greater volume flow. At certain low levels of upstream pressure P2, and therefore also operating pressure P3, regulator actuator 235 cannot physically open poppet valve 233 any further because it reaches the end of its motion, i.e., it strikes the end wall 237 of the space / cylinder in which it moves. Consequently, at least a portion of surface 238 of regulator actuator 235 is pushed against end wall 237. This can occur, for example, when gas fuel system 200 is being emptied, because operating pressure P3 is too low to counteract the force of regulator spring device 236.

[0140] In principle, the poppet 233 and seat 234 only come into contact when there is no flow through the regulator 230. Therefore, wear on the poppet 233 primarily occurs during this non-flow period. However, wear can also occur due to particles in the airflow downstream of the poppet 233. If the poppet 233 and seat 234 fail to achieve a tight seal to prevent flow, the downstream operating pressure P3 will continue to rise. This increase in operating pressure P3 will cause the regulator actuator 235 to move upward and push the poppet 233 into the seat 234 with greater force, which may cause the shape of the poppet 233 to deform. For example, this deformation can take the form of an annular recess on the surface of the poppet 233, where the annular recess becomes deeper as wear progresses. At some point, a seal will be achieved, and flow will be interrupted unless the regulator seat 234 is excessively deformed or worn.

[0141] In order to deal with the situation where the regulator seat 234 is too worn to achieve a tight seal with the poppet valve 233, the gas fuel system 200 may include a pressure reducing valve (PRV) 240 arranged on the downstream side (i.e., the working pressure P3 side) as part of the regulator 230 or separated from the regulator 230. Figure 3 For simplicity, the pressure reducing valve 240 is shown as part of the regulator 230. The pressure reducing valve 240 is arranged to set the pressure P PRV Fuel is released from the gas fuel system 200 to relieve overpressure, wherein the set pressure P PRVTypically it is slightly higher than the design pressure of downstream components (eg, injector 290), for example in the range of 10 to 12 bar.

[0142] Figure 4 A schematic cross-section of an example of a pressure relief valve 240 is shown. In its simplest form, the valve operates according to the principle of a pressure relief valve spring assembly 245 that closes the valve at a relatively low operating pressure P3. At a certain operating pressure P3 value, the pressure relief valve spring assembly 245 is compressed by the force applied by the gas to the pressure relief valve actuator 243, causing the actuator 243 to move away from its seat 244, thereby allowing gas to flow from the pressure relief valve inlet 241 through the pressure relief valve 240 and out of the pressure relief valve outlet 242. The outlet pressure relief valve outlet 242 may be connected to ambient pressure conditions. Thus, pressure relief of gas from the gas fuel system 200 at the operating pressure P3 is achieved.

[0143] In gas fuel system 200, debris and oil may be introduced into the fuel system during filling / refueling operations. Furthermore, grease may be introduced during the manufacturing of components of the gas fuel system. The amount of oil present in the fuel depends largely on the maintenance of the refueling station. Generally, maintaining the compressor and filter at the refueling station is important to ensure smooth operation of gas vehicles. Oil is used to ensure smooth operation of the compressor at the refueling station, but as the compressor wears, it consumes more and more oil. The oil from the refueling station needs to be filtered from the fuel in several filtration steps after passing through the compressor. Furthermore, as the gas expands in the regulator and passes through the area of poppet valve 233 and seat 234, the temperature of the gas drops, as explained by the Joule-Thomson effect. This temperature drop causes the oil in the gas to precipitate and adhere to the inner surfaces of the regulator, such as end wall 237 and actuator surface 238, which are in contact with each other.

[0144] If the surfaces between the regulator body and regulator actuator 235 (e.g., end wall 237 and actuator surface 238) are coated with oil or grease when engaged, depending on their geometry, they will be difficult to separate due to the operating pressure P3 acting on actuator surface 238, causing poppet valve 233 to become stuck open. This is because when surfaces 237, 238 are attempted to separate, a vacuum is created between them, contained by the capillary bridge of oil or grease. As is well known, a coaster (i.e., a small saucer) may adhere to the bottom of a glass if moisture is present between it and the bottom of the glass. Here, if oil or grease is present between the surfaces 237, 238 of the regulator body and regulator actuator 235, a similar vacuum effect will occur between them. This problem can occur, for example, during a shop inspection when the gas fuel system 200 is evacuated downstream of the controllable valve 211 during maintenance.

[0145] When operating the engine 101 at high engine fuel consumption, for example when the engine fuel consumption C is above the consumption threshold C th ; C>C th When the fuel tank is almost empty, for example, when the storage pressure P1 is lower than the storage pressure threshold P1 th ;P1 <P1 th This problem may also occur when each consumption threshold C th This can be compared with the storage pressure threshold P1 th Related, where the storage pressure threshold P1 th The value may be related to how well the regulator and the engine are matched, and may for example be in the range of 10-20 bar, which relates to when the regulator is fully open so that choking begins to occur.

[0146] When this fault occurs—that is, when poppet valve 233 becomes stuck in its open position—regulator 230 ceases to regulate pressure and instead opens fully. This can cause the operating pressure P3 downstream of regulator 230 to rise sharply, potentially approaching the storage pressure P1 and reaching as high as 200 bar on a fully filled tank. Pressure relief valve 240 is not designed to handle such high pressures and flows and is subsequently unable to release gas quickly enough to maintain a safe downstream pressure. The electrically controlled low-pressure / shutoff valve 260 is designed to handle such high pressures when necessary and therefore has a burst pressure consistent with high-pressure circuit system components. However, if low-pressure / shutoff valve 260 were to open, for example due to engine 101 being cranked, the downstream fuel filter 270 and / or downstream fuel lines / hoses could burst due to the high pressure. Such a component burst due to high pressure could result in vehicle off-road time and hearing loss and / or other injuries to the driver of vehicle 100.

[0147] Aspects and embodiments of the present invention at least partially address these problems.

[0148] Figure 5A flow chart illustrating a method 500 for controlling permission to start an engine is shown. The engine 101 is supplied with gaseous fuel via a gaseous fuel system 200. The gaseous fuel system includes one or more fuel tanks 210 configured to store fuel at a storage pressure P1, and one or more controllable valves 211 disposed downstream of the one or more fuel tanks 210 to provide fuel at an upstream pressure P2 to at least one regulator 230. The gaseous fuel system 200 also includes at least one regulator 230 disposed downstream of the one or more controllable valves 211 to regulate the upstream pressure P2 of the fuel downward to a lower operating pressure P3. Downstream of the regulator, a low-pressure valve 260 is disposed upstream of one or more components 270, 290 configured to provide fuel to the engine 101 at the operating pressure. At least one operating pressure sensor 280 is disposed at the engine, adjacent to one or more injectors 290, to measure the operating pressure P3.

[0149] It should be noted that Figure 5 The method steps shown and described herein do not necessarily have to be performed in Figure 5 The steps may be performed in essentially any suitable order, provided that the physical requirements and information necessary to perform each step are available at the time the step is performed.

[0150] Typically, as mentioned above, the method is most likely to be performed in conjunction with maintenance, for example during a workshop inspection.Since the method may also be performed during operation of the engine 101 with high engine fuel consumption, when the fuel tank is nearly empty.

[0151] In step s540 of the method, the low pressure valve 260 is closed.

[0152] In step s542 of the method, at least one of the one or more controllable valves 211 is controlled so that the gas fuel system 200 is pressurized upstream of the low-pressure valve 260. For example, the at least one controllable valve 211 can be controlled to open so that the upstream pressure P2 corresponds to the storage pressure P1. Then, the at least one controllable valve 211 is closed again. In this context, the gas fuel system is pressurized meaning that the upstream pressure P2 is higher than the upstream threshold value P2 th ;P2>P2 th . Upstream threshold P2 th It may be associated, for example, with a value of the upstream pressure P2 stored when the engine was previously stopped, which may indicate that a test of the gaseous fuel system should be performed. th It may also be associated with the filling of the fuel tank, which may cause the upstream pressure P2 to be high enough to cause damage to downstream components.

[0153] For example, if the engine 101 has been running with the fuel tank 210 almost empty and then the fuel tank 210 is filled with fuel, the upstream threshold P2 th It can be set to correspond to the upstream pressure P2 detected before filling the fuel tank 210. If the upstream pressure P2 detected before filling is low, for example 10 bar, and the engine does not experience any operating problems, it is possible that the regulator is then fully opened. Therefore, if the upstream pressure P2 detected after fuel filling is higher than the upstream threshold P2 th , it may be preferable to run a test to ensure that the regulator 230 is not stuck in its open position.

[0154] In step s544 of the method, the low-pressure valve 260 is opened. The gaseous fuel that was previously pressurized and closed upstream of the closed low-pressure valve 260 is thereby released to the remainder of the gaseous fuel system downstream of the low-pressure valve 260. Consequently, the gaseous fuel system downstream of the low-pressure valve 260 is now filled with gaseous fuel such that the operating pressure P3 increases.

[0155] In step s546 of the method, the increase in operating pressure ΔP3 after opening s544 of the low pressure valve 260 is monitored by using at least one operating pressure sensor 280. Thus, at least one operating pressure sensor 280 measures the operating pressure P3 and analyzes the increase in operating pressure ΔP3 as described herein.

[0156] In step s548 of the method, permission to start the engine 101 is controlled based on the monitored / detected increase in operating pressure ΔP3, as described in detail below.

[0157] Figure 6 Flowcharts illustrating various embodiments of the present invention.

[0158] It should be noted that Figure 6 The method steps shown and described herein do not necessarily have to be performed in Figure 6 The steps can be performed in essentially any suitable order, provided that the physical requirements and information required to perform each step are available at the time the step is performed. Figure 6 A number of embodiments are shown in FIG. 1 , so it should be noted that it is not necessary to perform a Figure 6 Therefore, when utilizing a particular embodiment, only the steps associated with that embodiment must be executed / performed.

[0159] exist Figure 6In step s502 of the embodiment, it is detected whether one or more initial conditions are met, as described below. If at least one of the initial conditions is met (Y), the method 500 is allowed to be executed. According to an embodiment, the method then proceeds to step s540, as Figure 6 If any initial condition (N) is not satisfied, step s502 is repeated.

[0160] One such initial condition is that at least one operating pressure sensor 280 detects that the operating pressure P3 is below a first operating pressure threshold value P3 th1 ;p3 <P3 th1 and also detecting that the vehicle 100 including the gas fuel system 200 is stopped, for example, by using a speedometer, accelerometer, or another device providing a suitable movement input. First operating pressure threshold P3 th1 Relatively low values can be assumed here, for example in the range of 4-5 bar.

[0161] Another such initial condition is that at least one operating pressure sensor 280 detects that the operating pressure P3 is higher than the second operating pressure threshold P3 th2 ;p3>P3 th2 ; and based on appropriate input, it is also detected that the vehicle 100 stops. Second working pressure threshold P3 th2 Relatively high values can be assumed here, for example at least 10 bar.

[0162] Another such initial condition is that the fault code has been activated because at least one operating pressure sensor 280 has measured an operating pressure P3 exceeding a third threshold value P3 th3 ;P3>P3 th3 , and fuel filling has been detected based on information associated with the fuel tank level, for example. Third operating pressure threshold P3 th3 In this case, it can have a value of at least 16 bar, for example.

[0163] It should be noted that if the gas fuel system 200 is not pressurized when the at least one controllable valve 211 is controlled to slowly open in step s542, that is, if the upstream pressure sensor 250 does not detect that the upstream pressure P2 is higher than the upstream pressure threshold P2 th , this may be caused, for example, by a technician attempting to vent gas from the gas fuel system and / or by manual valve 212 being closed. In this case, the method may include the additional step of activating a fault code to indicate that the fault(s) need to be repaired before continuing with the method.

[0164] According to an embodiment, if one or more initial conditions (Y) are met, the method proceeds to step s540.

[0165] In step s540 of the method, the low pressure valve 260 is closed.

[0166] In step s542 of the method, at least one of the one or more controllable valves 211 is controlled so that the gas fuel system 200 is pressurized upstream of the low-pressure valve 260. For example, the at least one controllable valve 211 can be controlled to open so that the upstream pressure P2 corresponds to the storage pressure P3. Then, the at least one controllable valve 211 is closed again. In this context, the gas fuel system is pressurized, which means that the upstream pressure P2 is higher than the upstream threshold value P2 th ;P2>P2 th . Upstream threshold P2 th It may be associated, for example, with a value of the upstream pressure P2 stored when the engine was previously stopped, which may indicate that a test of the gaseous fuel system should be performed. th It may also be associated with the filling of the fuel tank, which may cause the upstream pressure P2 to be high enough to cause damage to downstream components.

[0167] In step s508 of the method, the one or more controllable valves 211 are closed. As a result, the gaseous fuel system is now pressurized between the closed one or more controllable valves 211 and the closed low-pressure valve 260. This also means that the gaseous fuel volume is restricted / closed by the closed one or more controllable valves 211 and the closed low-pressure valve 260, so that fuel is present in the gaseous fuel system 200 from the upstream one or more fuel tanks 210 to the downstream closed low-pressure valve 260.

[0168] In step s510 of the method, the stability of upstream pressure P2 is monitored / determined using at least one upstream pressure sensor 250. Thus, at least one upstream pressure sensor 250 measures upstream pressure P2 and analyzes deviations / fluctuations in upstream pressure P2 as described herein. For example, if the deviation is less than a certain value, e.g., if the deviation does not decrease by more than 1 bar, then pressure P2 is determined to be stable. Conversely, if the deviation is greater than the value, then the pressure is determined to be unstable, which may indicate a leak somewhere in the system.

[0169] In step s512 of the method, permission to crank the engine 101 is controlled based on the monitored / detected stability.

[0170] If monitoring of upstream pressure P2 in step s510 indicates that upstream pressure P2 is unstable (U), then, according to an embodiment, the method proceeds from step s512 to one or more of steps S531-S533. In step s531, engine 101 is not allowed to start up, thereby preventing cracking and / or damage to downstream components. In step s532, a regulator fault is determined to be present, and in step s533, a regulator fault code is activated, indicating a regulator 230 fault.

[0171] If the upstream pressure P2 is monitored / detected as stable (S), then according to an embodiment, the method instead proceeds from step s512 to steps s514 - s516 to further analyze whether the regulator 230 and the pressure reducing valve 240 are functioning properly.

[0172] In step s514, the upstream pressure P2 is controlled to be reduced to the set pressure P of the pressure reducing valve 240. PRV For example, the upstream pressure P2 may be allowed to passively decrease to the set pressure P by closing one or more controllable valves 211. PRV .

[0173] In step s516, when the upstream pressure P2 drops to the set pressure P PRV At least one upstream pressure sensor 250 is used to detect the upstream pressure P2 and its stability. If the upstream pressure P2 deviates from the set pressure P2 during a certain period of time, PRV If the upstream pressure P2 deviates from the set pressure P PRV If it exceeds a certain value, it is considered unstable.

[0174] It should be noted that if the pressure relief valve 240 opens and releases the gaseous fuel due to a regulator malfunction, it may cause the upstream pressure P2 to become unstable. On the other hand, if the pressure relief valve 240 remains closed, this indicates that the regulator 230 is working properly. Then, the gaseous fuel is simply trapped in the closed volume, thereby stabilizing the upstream pressure P2.

[0175] In step s518, permission to start the engine 101 is controlled based on the stability detected in step s516. If the monitoring in step s516 indicates that the upstream pressure P2 is unstable (U), this may indicate a failure of the regulator 230, and according to an embodiment, the method proceeds from step s518 to one or more of the above-mentioned steps s531-s533 to prevent explosion and / or damage to downstream components. If the monitoring of the upstream pressure P2 in step s516 indicates that the upstream pressure P2 is stable (S), then according to an embodiment, the method proceeds from step s518 to step s520.

[0176] In step s520 , at least one of the one or more controllable valves 211 is controlled to open, so that the gas fuel system 200 downstream of the one or more controllable valves 211 and upstream of the low pressure valve 260 is filled with fuel, ie, pressurized again.

[0177] In step s522, the stability of the upstream pressure P2 after the filling in step s520 is monitored. At least one upstream pressure sensor 250 is used here to monitor the upstream pressure P2 and its stability.

[0178] In step s524, permission to start engine 101 is controlled based on the stability of upstream pressure P2 monitored in step s522. If monitoring upstream pressure P2 in step s522 indicates that upstream pressure P2 is unstable (U), this indicates that regulator 230 is not functioning properly, and, depending on the embodiment, the method proceeds from step s524 to one or more of steps s531-s533 described above to prevent rupture and / or damage to downstream components. If monitoring upstream pressure P2 in step s522 indicates that upstream pressure P2 is stable (S), this may indicate that regulator 230 has recovered, and, depending on the embodiment, the method proceeds from step s524 to step s540.

[0179] For example, if the gas fuel system 200 is pressurized to a suitable value, such as 13 bar, downstream of the one or more controllable valves 211 and upstream of the low-pressure valve 260, then if the upstream pressure P2 deviates from this suitable value by less than a certain value (e.g., 1 bar) during a certain period of time, it is considered stable. Conversely, if the upstream pressure P2 deviates from the suitable value by more than the certain value, it is considered unstable.

[0180] Combination of the above Figure 5 Steps s540 - s548 are described. In these steps, the increase ΔP3 of the working pressure after the opening s544 of the low-pressure valve 260 is monitored by using at least one working pressure sensor 280 .

[0181] If the working pressure increase ΔP3 detected by monitoring s546 is higher than the allowable value, that is, higher than (A) the first working pressure increase threshold ΔP3 th1 , that is, ΔP3>ΔP3 th1 , then according to an embodiment, the method proceeds to step s551, where starting the engine 101 is not allowed when the ignition system is enabled.

[0182] According to an embodiment, if the increase in the operating pressure ΔP3 is higher than (A) the first operating pressure increase threshold ΔP3 th1 ;ΔP3>ΔP3 th1, the method proceeds to step s552. In step s552, low-pressure valve 260 is closed, which prevents or limits further increases in operating pressure P3, i.e., mitigates further pressure increases in low-pressure circuit 202. The method then proceeds to step s553, where one or more injectors 290 arranged to inject fuel into engine 101 are opened, causing gaseous fuel to flow through one or more injectors 290, thereby reducing operating pressure P3. According to various embodiments, the method may then proceed to perform one or more of steps S554-S558.

[0183] Thus, according to some embodiments, one or more injectors 290 inject fuel into the intake manifold (boost chamber) of engine 101, and if any cylinders of the engine are on their intake stroke, those cylinders will also be filled with gas. Some engines may have both inlet and outlet valves open simultaneously, allowing gaseous fuel to flow through the cylinders. In this case, the exhaust gas treatment system may also be filled with gaseous fuel. This is still a preferred action over rupturing or damaging downstream components in gaseous fuel system 200.

[0184] As described below, the increase in working pressure ΔP3 and the first working pressure increase threshold ΔP3 th1 The values may include absolute values, derivative values, and / or values indicating changes over time. It should be noted that the operating pressure P3 is typically very low (e.g., zero bar) initially because the fuel system downstream of the low-pressure valve 260 is empty when the test is run, i.e., before the low-pressure valve 260 is opened in step s541. Therefore, the absolute value of the increase in operating pressure ΔP3 may also correspond to the absolute value of the operating pressure P3. Correspondingly, the first operating pressure increase threshold ΔP3 is th1 The absolute value of may correspond to an absolute threshold value of the working pressure P3.

[0185] First working pressure increase threshold ΔP3 th1 It may have a value such that the ejector or ejectors 290 open fast enough to mitigate a dangerous operating pressure increase, for example 10 bar in the case where the increase in operating pressure ΔP3 is an absolute value.

[0186] If the increase in the operating pressure ΔP3 indicates some change in pressure over time, such as a derivative value, then the first operating pressure increase threshold ΔP3 th1 is the corresponding threshold value that changes with time. For example, the first working pressure increase threshold value ΔP3 th1The closing time of the low pressure valve 260 may be associated, which may be in the range of 60-100 ms, for example, so that a dangerous pressure increase during this closing time can be avoided. In general, an excessively high operating pressure ΔP3, for example above 13 bar, which may prevent the opening of one or more injectors 290, should be avoided. This can be achieved by increasing the first operating pressure by a threshold value ΔP3. th1 This can be achieved by setting appropriate values for absolute changes, derivatives, and / or changes over time. By analyzing the derivative or other changes over time and setting corresponding thresholds accordingly, such excessive operating pressures P3 can be mitigated before they occur. Therefore, if the pressure derivative or other changes over time are fast / steep / high, this provides an early indication that a dangerous situation may occur later. Low-pressure valve 260 can then be closed in time to avoid the dangerous situation.

[0187] In some cases where it is impossible to avoid an excessively high working pressure ΔP3, a first working pressure increase threshold ΔP3 may be selected. th1 The operating pressure ΔP3 is maintained within the measuring range of the operating pressure sensor 280, for example, below 16 bar, so that at least a detectable operating pressure P3 is achieved. The excessive operating pressure ΔP3 can then be reduced by opening one or more connections in the gas fuel system 200, thereby releasing gas from the system.

[0188] In step s554 , the one or more controllable valves 211 are closed so that no further gaseous fuel is provided from the one or more fuel tanks 210 .

[0189] In step s555 , a regulator fault code is activated so that a regulator 230 fault is indicated to the driver and / or technician.

[0190] In step s556, the ignition system is disabled, for example, by disabling the ignition spark and / or disabling pilot injection of fuel used to ignite the gaseous fuel. Furthermore, after the ignition system has been disabled, cranking of the engine 101 is initiated in step s557. By cranking the engine 101 while the ignition system is disabled, the gaseous fuel is pumped through the engine without being ignited. Consequently, the operating pressure P3 is reduced, and the risk of rupture and damage to downstream components 270, 290 is reduced.

[0191] In step s558, the engine 101 is controlled to operate in a special mode. In this special mode, when the ignition system is disabled, the gas volume in the engine's air intake and in the cylinders of the engine 101 is replaced by air. Thus, the risk of explosion and damage to downstream components 270, 290 is reduced.

[0192] Therefore, when one or more injectors 290 are open, the engine 101 may be difficult to start, and combustible gases will be present in the air inlet manifold of the engine 101 and possibly also in the exhaust treatment system. If the engine is started in this mode, components of the exhaust treatment system may be damaged. Therefore, according to some embodiments, in this case, the engine 101 should be controlled to operate in a special mode in which the gas volume in the engine's air inlet and in the cylinders is pushed out and replaced with air without igniting the spark plugs. This is achieved by starting the engine without opening any fuel system valves, thereby pushing and / or consuming the gas mixture in the air inlet manifold and (multiple) cylinders. As a result, the gas mixture is thereby pushed through the engine and the exhaust treatment system without damaging downstream components, the engine or the exhaust treatment system.

[0193] According to an embodiment, if the increase in the working pressure ΔP3 monitored in step s546 has an allowable level, ie, is lower than (B) the second working pressure increase threshold ΔP3 th2 , that is, ΔP3<ΔP3 th2 , then it is determined that the regulator 230 is functioning properly and the method proceeds to step s561 , where cranking of the engine 101 is permitted. Thus, the starter motor may then be activated.

[0194] As described below, the increase in operating pressure ΔP3 and the second operating pressure increase threshold ΔP3 th2 The values may include absolute values, derivative values, and / or values indicating changes over time, respectively.

[0195] Second working pressure increase threshold ΔP3 th2 It is possible to have values such that a safe determination of a properly functioning regulator 230 is achieved, for example 9 bar for the increase ΔP3 in operating pressure in absolute terms.

[0196] According to various embodiments, the increase in the working pressure ΔP3 monitored in step s546 and / or the first working pressure increase threshold ΔP3 th1 and the second working pressure increment threshold ΔP3 th2 Absolute values, derivative values (ie pressure change per time unit) and / or values indicative of changes over time may be included, respectively. Essentially, any type of value / measurement indicative of increasing pressure that may be associated with a time interval may be detected and evaluated.

[0197] According to aspects of the present invention, Figure 1 、 27 and 7 schematically illustrate a processing device 145 of the engine control system 140. The processing device 145 is configured to control permission to start the engine 101, wherein the engine 101 is configured to be supplied with gaseous fuel by the above-mentioned gaseous fuel system 200. The processing device 145 is configured to perform the steps of the method, namely to perform the following steps: - closing s540 the low-pressure valve 260;

[0198] - controlling s542 at least one of the one or more controllable valves 211 so that the gas fuel system 200 is pressurized upstream of the low-pressure valve 260 ;

[0199] - Open s544 low pressure valve 260;

[0200] - after opening s544 the low pressure valve 260 , monitoring s546 the increase ΔP3 of the working pressure by using at least one working pressure sensor 280 ; and

[0201] - Controlling s548 the cranking of the engine 101 based on the monitored increase in operating pressure ΔP3.

[0202] The processing device 145, which is a control unit, control device, or device, is also configured to perform the method steps of the embodiments described herein. Thus, the processing device 145 is configured so that it can perform the method steps described herein, namely, method steps s502, s508, s510, s512, s514, s516, s518, s520, s522, s524, s531, s532, s533, s540, s542, s544, s546, s548, s551, s532, s533, s551, s552, s553, s554, s555, s556, s557, s558, and s561. These method steps may be executed / performed by corresponding control entities 602, 608, 610, 612, 614, 616, 618, 620, 622, 624, 631, 632, 633, 640, 642, 644, 646, 648, 651, 632, 633, 651, 652, 653, 654, 655, 656, 657, 658 and 661. The processing device 145 thus has the above-mentioned advantages of each corresponding embodiment.

[0203] Those skilled in the art will recognize that the embodiments described herein for braking a vehicle can also be implemented in a computer program that, when executed in a computer, instructs the computer to perform the method. The computer program typically comprises a computer program product 703 stored on a non-transitory / non-volatile digital storage medium, wherein the computer program is incorporated into a computer-readable medium of the computer program product. The computer-readable medium includes suitable memory such as, for example, ROM (Read Only Memory), PROM (Programmable Read Only Memory), EPROM (Erasable Programm ...

[0204] Figure 7 In a schematic representation a processing device / control unit 700 / 145 is shown which may comprise one or more of the above-mentioned control entities 602, 608, 610, 612, 614, 616, 618, 620, 622, 624, 631, 632, 633, 640, 642, 644, 646, 648, 651, 632, 633, 651, 652, 653, 654, 655, 656, 657, 658 and 661. The control unit 700 / 145 comprises a computing unit 701 which may be constituted by a processor or microcomputer of substantially any suitable type, such as a circuit for digital signal processing (digital signal processor, DSP) or a circuit with a predetermined specific function (application specific integrated circuit, ASIC). The calculation unit 701 is connected to a memory unit 702 arranged in the control unit 700 / 145, which provides the calculation unit 701 with, for example, stored program code and / or stored data required for the calculation unit 701 to be able to perform calculations. The calculation unit 701 is also arranged to store partial or final results of the calculations in the memory unit 702.

[0205] Furthermore, the control unit 700 / 145 is provided with means 711, 712, 713, 714 for receiving and transmitting input and output signals. These input and output signals may contain waveforms, pulses, or other properties that can be detected as information by the means 711, 713 for receiving input signals and converted into signals that can be processed by the computing unit 701. These signals are then made available to the computing unit 701. The means 712, 714 for transmitting output signals are arranged to convert the signals received from the computing unit 701 in order to create output signals, for example by modulating the signals, which can be transmitted to other components and / or systems in the vehicle.

[0206] Each connection of the means for receiving and transmitting input and output signals may be formed by one or more cables, a data bus such as a CAN bus (Controller Area Network bus), a MOST bus (Media Oriented System Transport bus), or some other bus configuration; or by a wireless connection. Those skilled in the art will recognize that the above-mentioned computer may be formed by the computing unit 701, and the above-mentioned memory may be formed by the memory unit 702.

[0207] The control system in a modern vehicle typically includes a communication bus system comprising one or more communication buses for linking a plurality of electronic control units (ECUs) or controllers and various components located on the vehicle. Such a control system may include a large number of control units and may divide the responsibility for a particular function between more than one control unit. Thus, a vehicle of the type shown typically includes more than Figure 1 、 2 There are significantly more control units than those shown in FIG. 7 , which are known to those skilled in the art.

[0208] In the embodiment shown, the present invention may be implemented by one or more of the above-mentioned control entities 602, 608, 610, 612, 614, 616, 618, 620, 622, 624, 631, 632, 633, 640, 642, 644, 646, 648, 651, 632, 633, 651, 652, 653, 654, 655, 656, 657, 658 and 661 of the processing device / control unit 700 / 145. However, the present invention may also be implemented in whole or in part in one or more other control units already present in the vehicle, or in some control units dedicated to the present invention.

[0209] Here and in this document, units are generally described as being arranged to perform the steps of the method according to the invention. This also includes that these units are designed and / or configured to perform these method steps.

[0210] One or more control entities 602, 608, 610, 612, 614, 616, 618, 620, 622, 624, 631, 632, 633, 640, 642, 644, 646, 648, 651, 632, 633, 651, 652, 653, 654, 655, 656, 657, 658, and 661 are Figure 1However, these entities 602, 608, 610, 612, 614, 616, 618, 620, 622, 624, 631, 632, 633, 640, 642, 644, 646, 648, 651, 632, 633, 651, 652, 653, 654, 655, 656, 657, 658, and 661 may be logically separate but physically implemented in the same unit, or may be logically and physically arranged together. These entities 602, 608, 610, 612, 614, 616, 618, 620, 622, 624, 631, 632, 633, 640, 642, 644, 646, 648, 651, 632, 633, 651, 652, 653, 654, 655, 656, 657, 658 and 661 may correspond, for example, to groups of instructions, which may be in the form of programming code, which are respectively input into and used by the processor / computing unit 701 when it is active and / or used to perform its method steps.

[0211] The present invention is not limited to the embodiments described above. On the contrary, the present invention relates to and encompasses all different embodiments included within the scope of the independent claims.

Claims

1. A method (500) for controlling permission to start an engine (101), the engine (101) being configured to be supplied with gaseous fuel by a gaseous fuel system (200); The gas fuel system (200) comprises: - one or more fuel tanks (210) configured to store fuel at a storage pressure (P1); - one or more controllable valves (211) arranged downstream of the one or more fuel tanks (210) to supply fuel to at least one regulator (230) at an upstream pressure (P2); - said at least one regulator (230) arranged downstream of said one or more controllable valves (211) for regulating the upstream pressure (P2) of the fuel downward to a lower operating pressure (P3); - a low-pressure valve (260) arranged downstream of the at least one regulator (230); - one or more components (270, 290) arranged downstream of the low-pressure valve (260) to supply fuel to the engine (101) at the operating pressure (P3); and - at least one operating pressure sensor (280) arranged at the engine (101); The method comprises the following steps: - closing (s540) the low pressure valve (260); - controlling (s542) at least one of the one or more controllable valves (211) such that the gas fuel system (200) is pressurized upstream of the low-pressure valve (260); - opening (s544) the low pressure valve (260); - monitoring (s546) the increase (ΔP3) of the working pressure by using the at least one working pressure sensor (280) after opening (s544) the low pressure valve (260); and - controlling (s548) permission to start said engine (101) based on the monitored increase in operating pressure (ΔP3).

2. The method (500) according to claim 1, wherein: If the monitored working pressure increase (ΔP3) is higher than the first working pressure increase threshold (ΔP3 th1 ;ΔP3>ΔP3 th1 ), the method comprises the following steps: - Closing (s552) the low pressure valve (260).

3. The method (500) according to claim 2, wherein the method comprises the following steps: - opening (s553) one or more injectors (290) arranged to inject fuel into said engine (101).

4. The method (500) according to claim 3, further comprising one or more steps from the group consisting of: - closing (s554) said one or more controllable valves (211); -Activate (s555) regulator fault code; - disabling (s556) the ignition system and starting (s557) cranking of said engine (101); as well as - controlling (s558) the engine (101) to operate in a special mode in which the gas volume in the air inlet of the engine (101) and in the cylinders of the engine (101) is replaced when the ignition system is disabled.

5. The method (500) according to any one of claims 1 to 4, wherein: If the monitored working pressure increase (ΔP3) is higher than the first working pressure increase threshold (ΔP3 th1 ;ΔP3>ΔP3 th1 ),but: - controlling (s548) the permission to start said engine (101) comprises not allowing (s551) the starting of said engine (101) when the ignition system is enabled.

6. The method (500) according to any one of claims 1 to 5, wherein: If the monitored working pressure increase (ΔP3) is lower than the second working pressure increase threshold (ΔP3 th2 ; ΔP3<ΔP3 th2 ),but: - Controlling (s548) the permission to start said engine (101) comprises allowing (s561) the starting of said engine.

7. The method (500) according to any one of claims 1 to 6, wherein the gas fuel system (200) comprises a pressure reducing valve (240) arranged to reduce the pressure at a set pressure (P PRV ) releases fuel from the gas fuel system (200), and wherein, Between the step of controlling (s542) at least one of the one or more controllable valves (211) so that the gas fuel system (200) is pressurized upstream of the low-pressure valve (260) and the step of opening (s544) the low-pressure valve (260), the method comprises the following steps: - closing (s508) said one or more controllable valves (211); - monitoring (s510) the stability of said upstream pressure (P2) by using at least one upstream pressure sensor (250); and - controlling (s512) permission to start said engine (101) based on the monitored stability.

8. The method (500) of claim 7, wherein: If the upstream pressure (P2) is stable, the method (500) further comprises the following steps: - Control (s514) the upstream pressure (P2) to reduce to the set pressure (P) of the pressure reducing valve (240) PRV ); - monitoring (s516) the upstream pressure (P2) by using the at least one upstream pressure sensor (250) to determine whether the upstream pressure (P2) decreases to the set pressure (P PRV ) stability when - controlling (s518) permission to start said engine (101) based on the monitored stability.

9. The method (500) of claim 8, wherein: If the upstream pressure (P2) is stabilized at the set pressure (P PRV ), the method (500) further comprises the following steps: - controlling (s520) at least one of the one or more controllable valves (211) to open so that the gas fuel system (200) downstream of the one or more controllable valves (211) and upstream of the low-pressure valve (260) is filled with fuel; - monitoring (s522) the stability of said upstream pressure (P2) after said filling by using said at least one upstream pressure sensor (250); and - controlling (s524) permission to start said engine (101) based on the monitored stability.

10. The method (500) according to any one of claims 7 to 9, wherein: If the monitoring (s510, s516, s522) indicates that the upstream pressure (P2) is unstable, then: - controlling (s512, s518, s524) the permission to start the engine (101) includes not allowing (s531) the starting of the engine (101).

11. The method (500) according to any one of claims 7 to 10, wherein: If the monitoring (s510, s516, s524) indicates that the upstream pressure (P2) is unstable, the method further comprises at least one step from the following group: - determining (s532) that there is a regulator fault; and -Activate (s533) regulator fault code.

12. The method (500) of claim 9, wherein: If said monitoring (s522) indicates that said upstream pressure (P2) is stable after said filling, then: - The step of controlling (s524) the permission to start said engine (101) comprises proceeding with the step of opening (s544) said low pressure valve (260).

13. The method (500) according to any one of claims 1 to 12, wherein: The monitored working pressure increase (ΔP3) and the first working pressure increase threshold (ΔP3 th1 ) and the second working pressure increase threshold (ΔP3 th2 ) include one or more of the following groups: - absolute value; - derivative values; and - Indicates a value that changes over time.

14. The method (500) according to any one of claims 1 to 13, wherein the method (500) further comprises the following steps: If one or more initial conditions from the following group are met: - the at least one working pressure sensor (280) detects that the working pressure (P3) is lower than a first working pressure threshold (P3 th1 ;P3 <P3 th1 ), and the vehicle (100) including the gas fuel system (200) stops; - the at least one working pressure sensor (280) detects that the working pressure (P3) is higher than a second working pressure threshold (P3 th2 ;P3>P3 th2 ), and the vehicle (100) including the gas fuel system (200) stops; and - indicates that the working pressure (P3) has exceeded the third threshold value (P3 th3 ;P3>P3 th3 ) fault code has been activated and fuel filling has been performed, - then allowing (s502) the execution of the method (500).

15. The method (500) according to any one of claims 1-14, wherein the method is performed in combination with one of the following group: -maintain; - Workshop inspections; and - when the storage pressure (P1) is lower than the storage pressure threshold (P1 th ;P1 <P1 th ) and the engine fuel consumption (C) is higher than the consumption threshold (C th ; C>C th )hour.

16. A processing device (145) configured to control permission to start an engine (101), the engine being configured to be supplied with gaseous fuel by a gaseous fuel system (200); The gas fuel system (200) comprises: - one or more fuel tanks (210) arranged to store fuel at a storage pressure (P1); - one or more controllable valves (211) arranged downstream of the one or more fuel tanks (210) to supply fuel to at least one regulator (230) at an upstream pressure (P2); - said at least one regulator (230) arranged downstream of said one or more controllable valves (211) for regulating the upstream pressure (P2) of the fuel downward to a lower operating pressure (P3); - a low-pressure valve (260) arranged downstream of the at least one regulator (230); - one or more components (270, 290) arranged downstream of the low-pressure valve (260) to supply fuel to the engine (101) at the operating pressure (P3); and - at least one operating pressure sensor (280) arranged at the engine (101); The processing device (145) is configured to perform the following steps: - closing (s540) the low pressure valve (260); - controlling (s542) at least one of the one or more controllable valves (211) such that the gas fuel system (200) is pressurized upstream of the low-pressure valve (260); - opening (s544) the low pressure valve (260); - monitoring (s546) the increase (ΔP3) of the working pressure by using the at least one working pressure sensor (280) after opening (s544) the low pressure valve (260); and - controlling (s548) the cranking of the engine (101) based on the monitored increase in operating pressure (ΔP3).

17. A computer program comprising instructions which, when said program is executed by a computer, cause said computer to carry out the method according to any one of claims 1 to 15.

18. A computer-readable medium comprising instructions which, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 15.

19. A carrier (100), comprising: - an engine (101); - a gaseous fuel system (200) configured to provide fuel to the engine (101); and - A processing device (145) according to claim 16.

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