Method and control unit for operating a vehicle and computer program product

Abstract

Method for operating a vehicle (1) wherein the method comprises: - Detect that the vehicle is being refueled (1); - Determining location information for the vehicle (1); - Determining a fuel quality factor for the fuel supplied based on the determined location information, wherein the fuel quality factor characterizes the energy content of the fuel, characterized in that fuel quality factors and fuel quantities for fuel already in the tank (6) before the refueling process and for the fuel filled into the tank (6) during the refueling process are used for the determination, and wherein the determined fuel quality factor is adapted based on data from a lambda sensor (39) of the vehicle (1).

Description

[0001] The invention relates to a method for operating a vehicle powered, for example, by compressed gas, a control device for operating a vehicle and a computer program product.

[0002] A compressed gas is understood here and below to mean a fuel that is gaseous at atmospheric pressure and stored in a pressurized container in the vehicle. Examples include natural gas or hydrogen. The invention does not exclusively apply to vehicles powered by compressed gas, but also to vehicles powered by gasoline, diesel, or LPG (liquefied petroleum gas).

[0003] DE 10 2007 036 958 A1 discloses a fuel supply system for a natural gas-powered vehicle. This system includes a pressure reducing device to reduce the tank pressure from, for example, 200 bar to the lower system pressure of the injection device.

[0004] In such vehicles, the problem arises after refueling that an unknown gas mixture with unknown properties is present in the tank, as the quality of natural gas or compressed gases in general varies greatly due to their composition. For example, the natural composition can fluctuate and / or additives may be added. As has been shown, the energy content of natural gas, for example, can fluctuate by up to 50%. Since the combustion process in the vehicle is always calibrated to the current tank level, it may happen that a vehicle can no longer be started and / or no longer operates economically after refueling with the existing settings.

[0005] To solve this problem, a sensor can be used to analyze the gas in question for its components and derive the energy content from them. However, this is complex.

[0006] Another option is to initially run the vehicle on gasoline for starting after refueling and only switch to natural gas after the vehicle has been adapted. However, this requires a gasoline tank and is usually associated with higher fuel consumption, as the engines of compressed gas-powered vehicles are optimized for gas operation.

[0007] Fuel quality also varies with other fuels, so that adjustments to settings may be necessary after refueling.

[0008] Document DE 21 2006 000 080 U1 discloses an emission control system for a power source, comprising a navigation tool for detecting a geographical location of a power source; and a processor for comparing the geographical location of the power source with fuel location data stored in a database, wherein the emission control system is configured to modify, activate, or deactivate at least one engine system, or to activate or deactivate at least one power source warning system, based on a result of a comparison of the geographical location of the power source with the fuel location data.

[0009] Document US 2014 / 0 180 559 A1 discloses an engine control system and method, wherein the quality of the fuel in the engine is detected in relation to emissions, for example, by detecting the content of an emission-related component, such as sulfur. A fuel quality sensor detects the fuel quality of a fuel, such as the sulfur content in the fuel, and provides a signal dependent on the fuel quality. The engine control system includes a navigation device that can be used to determine whether an engine is located in a regulated or unregulated area. The engine control system receives the signal and controls engine operation, for example, by activating or deactivating one or more engine algorithms to improve engine performance based on the fuel quality signal or the combination of the fuel quality and the engine's location.

[0010] Document DE 10 2013 106 586 A1 discloses a method for operating a motor vehicle comprising a fuel-powered internal combustion engine, wherein a combustion process is monitored. To reduce malfunctions in the operation of the motor vehicle caused by low-quality fuel, the location of the motor vehicle is recorded during a refueling process using navigation data.

[0011] The document DE 103 41 090 A1 discloses a control device for a drive of a motor vehicle, in particular for monitoring an exhaust gas purification system of an internal combustion engine, with an integrated position detection device or a connection for connection to a position detection device arranged in the motor vehicle in order to take into account position data generated by the position detection device and reflecting the motor vehicle position when controlling the drive.

[0012] Document DE 10 2013 202 193 A1 discloses a method for operating a first motor vehicle, wherein at least one parameter relevant to the operation of the first motor vehicle is determined and at least one component of the first motor vehicle is controlled based on the at least one parameter. The at least one parameter is determined in at least one second motor vehicle.

[0013] The document DE 101 43 509 A1 discloses a method for controlling an internal combustion engine in a motor vehicle, wherein at least one estimated value of at least one parameter is determined which describes a property of a fuel which is supplied to the internal combustion engine for operation, and the internal combustion engine is controlled as a function of the estimated value of the parameter.

[0014] It is therefore an object of the present invention to provide a method for operating a fuel supply device with which a vehicle can be started and operated safely and efficiently even after refueling. Furthermore, a control unit for operating such a vehicle is to be provided.

[0015] This problem is solved by the subject matter of the independent claims. Advantageous further developments arise from the dependent claims.

[0016] According to one embodiment of the invention, a method for operating a vehicle is specified, wherein the method comprises determining a refueling process of the vehicle, determining location information for the vehicle and determining a fuel quality factor for the fuel being refueled based on the determined location information. In particular, the quality factor is determined based on the location information for the fuel supplied during refueling and based on a fuel quality factor of the fuel present in the tank at the start of the refueling process. The latter fuel quality factor results from previous operating parameters of the internal combustion engine. The more fuel still present at the start of the refueling process (i.e. "old fuel"), the smaller the influence of the quality factor of the fuel to be refueled on the (overall) quality factor.

[0017] Refueling is understood here and below to mean the filling of the vehicle with fuel, which can be detected, for example, by an increase in pressure in the gas tank or the signal from a fill level sensor.

[0018] The determined fuel quality factor indicates important properties of the fuel for combustion in the vehicle's internal combustion engine, in particular the energy content of the fuel.

[0019] According to one of the considerations underlying the invention, the varying quality of compressed gas, for example, is primarily due to the different origins of natural gas. Depending on the source, pure methane may be present, but there may also be varying admixtures of ethane, propane, butane, carbon dioxide, or nitrogen. This can result in significant fluctuations in the energy content of natural gas. The presence of additives intended to influence fuel properties such as starting ability, lubrication, particulate matter, energy content, and odor also leads to fluctuations in the energy content of the fuel.

[0020] However, gas quality does not fluctuate unpredictably; rather, the gas quality available at a gas station is the result of supply chains and can therefore be statistically estimated. Therefore, the vehicle's location is first determined, particularly during the refueling process, so that location information about the gas station is also obtained. Based on this location information, a fuel quality factor is then determined for the refueled gas. Based on the fuel quality factor, the engine control system can then make the necessary adjustments for efficient combustion.

[0021] Even for vehicles powered by other fuels, the vehicle's location during the refueling process can be usefully used to determine a fuel quality factor. For example, the location information can be used to access databases that provide current information on the sale of winter or summer diesel or on the composition of biodiesel at the respective filling station.

[0022] According to one embodiment, map or table information stored in a local memory of the vehicle is used to determine the fuel quality factor based on the determined location information. It is also conceivable that the local memory is located in a cell phone or other mobile device of the vehicle driver. The map information stored in the local memory can, in particular, identify areas with a known fuel quality. The table information can contain the assignment of an individual location, for example, a specific gas station, to a known fuel quality. For example, these could be gas stations regularly visited by the user with a known fuel quality.

[0023] According to a further embodiment, map or table information provided via a network connection is used to determine the fuel quality factor based on the determined location information. This information can be used alternatively or in addition to information stored in a local memory.

[0024] This embodiment has the advantage that detailed and always up-to-date information can be made available via a network, especially the internet. The use of cloud applications has the advantage that a large number of users can share information with each other, ensuring that the most accurate and up-to-date data possible is available.

[0025] In addition to the determined location information, vehicle data, such as combustion pressure and pressure regulator temperature, can also be included in the calculation of the fuel quality factor. However, these parameters have only a minor influence.

[0026] According to one embodiment, location information is determined, for example, using GPS, Wi-Fi, triangulation, cell phone tracking, and / or identification data provided by the gas station. For example, the gas station could provide a barcode that can be scanned, for example, with a mobile device to obtain information about the location of the gas station and / or the fuel quality factor.

[0027] According to the invention, a parameter characterizing the energy content of the fuel mixture after the refueling process is further determined, using fuel quality factors and fuel quantities for the fuel still in the tank before the refueling process and for the fuel added to the tank during the refueling process. The fuel quantities can be determined, in particular, via the pressure or fill level in the tank. The fuel quality of the remaining quantity still in the tank before the refueling process can be obtained from data from the vehicle's lambda sensor or is known from a previous statistical estimate of the fuel quality factor.

[0028] The quality of the mixture in the tank is crucial for the combustion process, not just that of the fuel being added. The method therefore has the advantage of accurately determining the fuel quality factor of the fuel mixture, even with significant residual fuel in the tank.

[0029] According to the invention, the determined fuel quality factor is adapted based on data from a vehicle's lambda sensor. This provides a way to verify the statistical estimate and eliminate potential errors. If the fuel quality were accurately determined immediately after refueling, no unusual interventions in the control behavior by the lambda control should occur. However, if the lambda control suggests that the fuel quality was not accurately determined, the fuel quality factor can be subsequently adjusted using this embodiment of the method.

[0030] According to a further embodiment, an estimation is made from surrounding data points if no exact location information for the vehicle and / or no fuel quality factor for the fuel being refueled can be determined.

[0031] This embodiment is based on the idea that very precise knowledge of the location is not necessary if, for example, the gas station being visited is located in the middle of a uniform service area. In this case, it may not be necessary to determine which gas station is being refueled at; knowledge of the region in which the refueling takes place may be sufficient.

[0032] For example, if highly reliable fuel quality data is available for several gas stations in the neighborhood, it may be safer to rely on this data than using less reliable, outdated data for the gas station you're driving to. This is especially true when compressed natural gas is used as a fuel, the composition of which is often the same due to delivery routes within a region.

[0033] In order to assess whether available location information or information on the fuel quality factor is sufficiently accurate, various criteria can be used to evaluate the trustworthiness of the information, for example the signal strength of a GPS signal, errors in triangulation or mobile phone location, the timeliness of stored information, the source of stored information.

[0034] According to one embodiment, the determined fuel quality factor is stored locally and / or transmitted to a remote storage device via a network connection. This has the advantage that the fuel quality factor, once determined, is available for the vehicle in question and, if applicable, to other users.

[0035] In this way, a comprehensive database of fuel quality factors can be built and maintained so that the statistical estimation of fuel quality can be carried out with great accuracy.

[0036] If the fuel quality factor could not be determined with sufficient accuracy, for example because no location information could be determined or because no fuel quality factor could be assigned to this location information, it can be provided, particularly in vehicles powered by compressed gas, that the vehicle is started with a lean mixture after refueling. Since a mixture that is too rich may not be ignitable in vehicles powered by compressed gas, this procedure has the advantage that the vehicle can be started even if the fuel quality factor is not sufficiently known. In return, it is accepted that this is not optimal with regard to the combustion process. The fuel quality factor can then be determined from data from the lambda sensor.

[0037] The method therefore has the advantage that complex sensors for determining the fuel composition can be dispensed with.

[0038] A further aspect of the invention relates to a computer program product comprising a computer-readable medium and program code stored on the computer-readable medium, which, when executed on a computing unit of the vehicle, instructs the computing unit to carry out a method according to one of the aforementioned embodiments.

[0039] The computing unit is designed in particular as an engine control unit.

[0040] A further aspect of the invention relates to a control device for operating a vehicle, comprising at least one first receiving device, designed to receive information about a refueling process of the vehicle, at least one first determining device designed to determine standard information for the vehicle and at least one second determining device designed to determine a fuel quality factor for the fuel being refueled on the basis of the determined location information, wherein fuel quality factors and fuel quantities for fuel still in the tank before the refueling process and for the fuel filled into the tank during the refueling process are used for the determination, and wherein the determined fuel quality factor is adapted based on data from a lambda sensor of the vehicle.

[0041] The control unit can in particular be the engine control unit of the vehicle.

[0042] A further aspect of the invention relates to a vehicle with such a control unit, in particular a vehicle powered by compressed gas.

[0043] Embodiments of the invention will now be explained in more detail with reference to the accompanying figures. Fig. 1 schematically shows a flow diagram of a method for operating a compressed gas powered vehicle according to an embodiment of the invention and Fig. 2 shows schematically a vehicle for carrying out this method.

[0044] According to the method for operating a compressed gas powered vehicle shown in the flow chart in Fig. As shown in Figure 1, in a step 100, it is determined that the vehicle is being refueled with compressed gas. This can be done, in particular, by tank pressure sensors.

[0045] In a step 200, location information for the vehicle is then determined in order to determine the vehicle's location during the refueling process and thus the location of the gas station. For this purpose, a GPS sensor of the vehicle can be used, but location can also be determined via Wi-Fi, triangulation, cell phone tracking, or identification data provided by the gas station.

[0046] From this determined location information, a fuel quality factor is then determined in a step 300. To do this, the method accesses map or table information, with fuel quality factors stored in the maps or tables for a large number of locations. Fuel quality factors are assigned to locations, for example, based on known supply routes, on the filling stations' own information, and / or on users of the described method who report fuel quality factors obtained from data from the vehicle's lambda sensor.

[0047] Subsequently, in a step 400, the engine settings are adapted to the determined fuel quality factor, whereby if there is a residual amount of fuel in the tank, the energy content of this mixture is first determined in order to be able to make the correct engine settings.

[0048] In step 500, if necessary, the fuel quality factor can be adapted during vehicle operation using data from the lambda sensor. This adapted fuel quality factor can then be fed back by the vehicle or the user to improve the existing map or table information.

[0049] Fig. Figure 2 shows a vehicle 1, indicated only by dashed lines, which is designed, in particular, as a passenger car, truck, or bus. Vehicle 1 is powered by compressed natural gas (CNG) as fuel.

[0050] Alternatively, hydrogen could be used as a fuel.

[0051] The vehicle 1 has an internal combustion engine 2 with a number of cylinders 3 in which the natural gas is burned. In the embodiment shown, the internal combustion engine 2 has four cylinders 3, of which only one is shown.

[0052] The fuel reaches the combustion chamber of the cylinder 3 (not shown in detail) via a fuel injection device 4. A fuel distribution rail 5 is connected upstream of the fuel injection device 4 and distributes the fuel supplied from the supply line 10 into the individual fuel injection devices 4 and the cylinders 3 assigned to them.

[0053] The fuel injection device 4 typically operates at a fuel pressure of approximately 5–20 bar. This pressure P2 also prevails in the supply line 10. In contrast, the compressed natural gas is stored in tanks 6 designed as pressure vessels at a pressure P1 of approximately 200 bar. This pressure P1 also prevails in the supply line 7, which leads from the tanks 6 via a filter 8 to the pressure regulator 9. The pressure regulator 9 reduces the pressure P1 to the pressure P2.

[0054] A computing unit 30, designed as an engine control unit, is connected to the internal combustion engine 2 via a control line 47. The computing unit 30, in particular, controls the valves of the internal combustion engine accordingly in order to determine the injected fuel quantities, injection duration, and injection timing.

[0055] In order to be able to correctly determine these parameters which are crucial for the combustion process, the computing unit 30 requires the specification of a fuel quality factor for the gas stored in the tanks 6.

[0056] In order to be able to reliably determine the fuel quality factor for the new tank contents after a refueling process, the computing unit 30 has a processing unit 31 and a computer-readable medium 32, which can be designed as a memory, in particular as an EEPROM, flash memory or flash EEPROM or NVRAM. A program code is stored on the computer-readable medium 32, which, when executed on the computing unit 30, instructs the computing unit 30 to carry out the above-mentioned embodiments of the method according to Fig. 1 to execute.

[0057] The processing unit 31 may, for example, be an electronic processor, in particular a microprocessor or microcontroller.

[0058] The processing unit 31 has a first receiving device 33, which is connected to a tank pressure sensor 36 via a signal line 41. The first receiving device 33 is thus designed to receive information about a refueling process of the vehicle 1. If the first receiving device 33 receives information that refueling is currently taking place, the computing unit 30 initiates the determination of location information for the vehicle 1 by the first determination device 34. For this purpose, the first determination device 34 is connected to a GPS sensor 37 via a signal line 42. It is thus designed to determine location information for the vehicle.

[0059] A second determination device 35 receives the determined location information for vehicle 1 via a connection 43 and, based on this, determines a fuel quality factor for the refueled gas. To do so, the second determination device 35 accesses data stored in the computer-readable medium 32 as local memory via the connection 44. Furthermore, it accesses data from the lambda sensor 39 via the signal line 45. Furthermore, it accesses data from a remotely arranged memory 38 via the radio connection 46. The second determination device is thus designed to determine a fuel quality factor for the refueled gas based on the determined location information.

[0060] If the second determination device 35 has successfully determined the fuel quality factor for the fueled gas, it then determines the fuel quality factor for the mixture in the tanks 6, if applicable. The combustion engine 2 is controlled based on this fuel quality factor of the mixture.

[0061] During subsequent operation of the vehicle 1, the determined fuel quality factor can be adapted using data from the lambda sensor 39, if necessary.

[0062] The computing unit 30 reports the fuel quality factor determined for the refueled gas back to the remotely arranged memory 38, which may in particular be a cloud server, and / or stores it in the local memory, the computer-readable medium 32.

[0063] An indirectly determined fuel quality factor is thus available for the operation of the combustion engine 2. A separate sensor for determining the fuel composition in the tanks 6 for a direct determination of the fuel quality factor is therefore not required. List of reference symbols 1 vehicle 2 combustion engine 3 cylinders 4 Fuel injection device 5 Fuel rail 6 tanks 7 Supply line 8 filters 9 pressure regulators 10 supply line 30 computing units 31 processing unit 32 computer-readable medium 33 first receiving device 34 first investigative device 35 second detection device 36 Tank pressure sensor 37 GPS sensor 38 remote storage 39 Lambda sensor 41 Signal line 42 Signal line 43 Connection 44 Connection 45 Signal line 46 Connection 47 Control line 100 steps 200 steps 300 steps 400 steps 500 steps

Claims

[1] Method for operating a vehicle (1), the method comprising: - Detecting a refuelling operation of the vehicle (1); - Determining location information for the vehicle (1); - Determining a fuel quality factor for the fuel pumped based on the determined location information, whereby the fuel quality factor indicates the energy content of the fuel, characterized by that fuel quality factors and fuel quantities are used for the determination of the fuel still in the tank (6) before the refueling process and for the fuel filled into the tank (6) during the refueling process, and wherein the determined fuel quality factor is adapted based on data from a lambda probe (39) of the vehicle (1). [2] Method according to claim 1, wherein map or table information stored in a local memory is used to determine the fuel quality factor based on the determined location information. [3] Method according to claim 1 or 2, wherein map or table information provided via a network connection is used to determine the fuel quality factor based on the determined location information. [4] Method according to one of claims 1 to 3, wherein the determination of location information is carried out by means of GPS, WLAN, triangulation, mobile phone tracking and / or identification data provided by the petrol station. [5] Method according to one of claims 1 to 4, wherein an estimation is made from surrounding data points if no precise location information for the vehicle (1) and / or no fuel quality factor for the fuel tanked can be determined. [6] Method according to one of claims 1 to 5, wherein the determined fuel quality factor is stored locally and / or transmitted to a remotely arranged memory (38) via a network connection (46). [7] Method according to one of claims 1 to 6, wherein a starting process of the vehicle (1) after a refueling process is carried out lean if the fuel quality factor could not be determined with sufficient accuracy. [8] A computer program product comprising a computer-readable medium (32) and program code stored on the computer-readable medium (32) which, when executed on a computing unit (30), instructs the computing unit (30) to carry out a method according to any one of claims 1 to 7. [9] Control device for operating a vehicle (1), comprising - at least one first receiving device (33) designed to receive information about a refueling process of the vehicle (1); - at least one first determination device (34) designed to determine location information for the vehicle (1); - at least one second determination device (35) designed to determine a fuel quality factor for the fuel pumped on the basis of the determined location information, characterized by that fuel quality factors and fuel quantities are used for the determination of the fuel still in the tank (6) before the refueling process and for the fuel filled into the tank (6) during the refueling process, and wherein the determined fuel quality factor is adapted based on data from a lambda probe (39) of the vehicle (1). [10] Vehicle (1) with a control device according to claim 9. [11] Vehicle (1) according to claim 10, which is operated with a compressed gas.

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