A diesel engine system with diesel fuel type detection

Abstract

A diesel engine system (101) for an agricultural machine (100) includes a diesel internal combustion engine (ICE) (201) configured to combust fossil diesel fuel and alternative diesel fuel, a knock sensor (213) integrated in the diesel internal combustion engine (201), a NOx sensor (209) and an electronic control unit (210). The electronic control unit (210) is configured to receive a knocking signal from the knock sensor (213), receive a NOx concentration signal from the NOx sensor (209), determine a fuel specific characteristic value based on the knocking signal and the NOx concentration signal, determine a fuel specific reference value, compare the fuel specific characteristic value with the fuel specific reference value, and determine whether the combusted diesel fuel is fossil diesel fuel or alternative diesel fuel.

Description

Docket No. 25001 / WOA DIESEL ENGINE SYSTEM WITH DIESEL FUEL TYPE DETECTIONFIELD

[0001] The present disclosure relates to a diesel engine system with a diesel internal combustion engine (ICE).BACKGROUND

[0002] Diesel engine systems are widely spread in the area of agriculture, construction and others. They comprise a diesel internal combustion engine to provide a drive torque by combusting diesel fuel. There are different types of diesel fuels which may be supplied to the diesel internal combustion engine. The most common type of diesel fuel is still fossil diesel fuel. But the combustion of fossil diesel generates exhaust gases comprising particulate matter as well as nitrogen oxides (NOX) which have harmful impact on the environment. With the aim of providing alternative diesel fuels for a more environment friendly combustion, different types of paraffinic diesel fuels have been developed.

[0003] Fossil diesel fuel (also called petroleum diesel) is derived from crude oil through a refining process (fractional distillation). Fossil diesel fuel contains a mix of hydrocarbons, including paraffins, naphthenes, and aromatics. It typically has higher levels of sulfur and other impurities. Thus, the combustion of fossil diesel fuel generally results in higher emissions of NOx, particulates, and CO2 compared to alternative diesel fuel.

[0004] Alternative diesel fuel may be any diesel fuel other than fossil diesel fuel such as a paraffinic diesel fuel, for example. Paraffinic diesel fuels can be produced synthetically from any carbonaceous material, including biomass, biogas, natural gas, coal and many others through processes like Gas-to-Liquid (GtL), Coal-to-Liquid (CtL), Power-to-Liquid (PtX) (also called eDiesel) and Biomass-to-Liquid (BtL), or from renewable sources like hydrotreated vegetable oils (HVO). The raw material is gasified into synthesis gas, which after purification is converted to a synthetic diesel. Accordingly, the types of paraffinic diesel fuels can be distinguished by the sources or the processes they have been produced. Paraffinic diesel fuels contain primarily paraffins (alkanes), which are straight-chain hydrocarbons. They contain almost no sulfur, nitrogen, oxygen, aromatics or particulate matter. Thus, the combustion of paraffinic diesel fuels may produce lower emissions of nitrogen oxides (NOX) and particulates.Docket No. 25001 / WOThe combustion can be CCh-reduced or even CCh-neutral, especially when produced from renewable sources. Paraffinic diesel fuel has a higher cetane number resulting in better ignition properties and a more efficient combustion. The higher cetane number may also compensate the effect of a lower density of paraffinic fuels. The usage of HVO or eDiesel could also decrease the soot load of diesel particulate filters.

[0005] Hence, the emission of harmful pollutants can be reduced when alternative diesel fuel is combusted by a diesel internal combustion engine instead of fossil diesel fuel. Optionally, the performance of the diesel internal combustion engine may be optimized. But the settings and / or the control of the diesel internal combustion engine needs to be adjusted to the specific properties of alternative diesel fuel to make advantage of the usage of alternative diesel fuel. If the type of diesel fuel combusted by the diesel internal combustion engine could be determined by an electronic control unit, the settings and / or the control of the diesel internal combustion engine could be automatically adjusted by the electronic control unit.

[0006] The following abbreviations may be used in this disclosure:

[0007] DEF: diesel exhaust fluid;

[0008] DPF: diesel particulate filter;

[0009] DOC: diesel oxidation catalyst;

[0010] SCR: selective catalytic reduction;

[0011] ICE: internal combustion engine;

[0012] EAT: engine aftertreatment system;

[0013] FSCV: fuel specific characteristic value;

[0014] PCB: printed circuit board;

[0015] ECU: electronic control unit;

[0016] I / O: input / output.BRIEF SUMMARY

[0017] The type of diesel fuel stored in a fuel tank could be detected by a fuel sensor installed in the fuel tank. But such kind of fuel sensors can be very sensitive to air bubbles in the diesel fuel affecting the measurement accuracy and causing signal noise. Since agricultural or construction machines are typically working on rough terrain causing vibrations of the fuelDocket No. 25001 / WOtank, the generation of air bubbles in the diesel fuel cannot be avoided. Hence, it is an object of the present disclosure to provide a robust and accurate determination of the type of diesel fuel supplied to an diesel internal combustion engine to adjust the settings and / or control of the diesel internal combustion engine and / or an engine aftertreatment system in accordance with the properties of the corresponding type of diesel fuel. The creation of air bubbles in the diesel fuel may not affect the robustness and accuracy of the determination of the type of the diesel fuel.

[0018] According to an aspect of the invention there is provided a diesel engine system for an agricultural machine, including a diesel internal combustion engine (ICE) configured to combust fossil diesel fuel and alternative diesel fuel, a knock sensor integrated in the diesel internal combustion engine, a NOXsensor, and an electronic control unit. The electronic control unit is configured to receive a knocking signal from the knock sensor, receive a NOXconcentration signal from the NOXsensor, determine a fuel specific characteristic value (FSCV) based on the knocking signal and the NOXconcentration signal, determine a fuel specific reference value (FSRV), compare the fuel specific characteristic value with the fuel specific reference value; and determine whether the combusted diesel fuel is fossil diesel fuel or alternative diesel fuel.

[0019] The agricultural machine may be an agricultural vehicle such as a tractor, a harvester, a combine, a sprayer, etc., optionally connected with an implement. The diesel ICE may have a cylinder block and combust fossil diesel fuel, alternative diesel fuel or a mixture thereof to generate motive power to propel the agricultural machine and / or to provide power for the implement, for example transferred by means of a power take-off shaft. The alternative diesel fuel may be any diesel fuel other than fossil diesel fuel as mentioned above. The exhaust gases produced by the combustion of the diesel fuel may be transmitted from the diesel ICE to an engine aftertreatment system of the diesel engine system to reduce the emission of harmful pollutants. The NOXsensor may be arranged in the engine aftertreatment system and measure the NOXconcentration in the exhaust gases. For example, NOXconcentration may be 2 to 10% lower when alternative fossil fuel is combusted in comparison to fossil fuel. So, NOXconcentration is a useful parameter to identify the type of the combusted diesel fuel.

[0020] The knock sensor may be of the same type as typically used in Otto ICEs. During the combustion of fossil or alternative diesel fuel, knocking due to abnormal vibrations creating sounds in the cylinder block may occur. This effect may arise because of the cetane numberDocket No. 25001 / WOdifference between fossil diesel fuel and alternative diesel fuel (e. g., fossil fuel may have cetane number of about 55 whereas alternative diesel fuel may have cetane number of more than 80) and different delays for ignition and combustion in the cylinder block. For example, alternative diesel fuel may ignite earlier than fossil diesel fuel. Such kind of knocking may be detected by the knock sensor as different acceleration signal profiles in specific cylinders of the cylinder block. In response thereof, a corresponding knocking signal is provided by the knock sensor that represents a bypass filtered acceleration amplitude as a function of crank angle of the diesel ICE. The knock sensor may detect different acceleration signal profiles in the cylinder block of the diesel ICE in dependence of the type of the diesel fuel.

[0021] The fuel specific reference value (FSRV) may be retrieved by the electronic control unit from a memory of the electronic control unit. The fuel specific reference value may be a predefined value or range of values representing a reference for alternative diesel fuel. The fuel specific reference value may be based on empirical values for combusting alternative diesel fuel. If the fuel specific characteristic value (FSCV) representing the diesel fuel combusted by the diesel ICE matches with the fuel specific reference value (FSRV), the electronic control unit may detect a combustion of alternative diesel fuel. Otherwise, a combustion of fossil diesel fuel may be detected.

[0022] The fuel specific characteristic value (FSCV) is a value representative for the type of diesel fuel combusted by the diesel ICE. The fuel specific characteristic value may be calculated by the electronic control unit based on an algorithm or determined by means of a reference stored in the memory of the electronic control unit. The reference may be a look-up table or a characteristic curve map with knocking signal curves (values) and NOXconcentration signal curves (values) representative for the different types of diesel fuels. So, dependent on whether the type of the combusted diesel fuel is fossil diesel fuel or alternative diesel fuel, the electronic control unit may determine a fuel specific characteristic value representing fossil diesel fuel or alternative diesel fuel according to the type of the combusted diesel fuel. Then, the type of the combusted diesel fuel can be determined by the comparison of the fuel specific characteristic value (FSCV) with the fuel specific reference value (FSRV) without the usage of a fuel sensor.

[0023] The diesel ICE may include an exhaust line. The NOXsensor may be arranged at the exhaust line.Docket No. 25001 / WO

[0024] The engine aftertreatment system may be connected with the exhaust line of the diesel ICE. The NOx sensor may be arranged between the diesel ICE and the engine aftertreatment system so that the NOXconcentration in the exhaust gases can be determined as vented by the diesel ICE before the NOXconcentration may be reduced by the engine aftertreatment system. Hence, it can be avoided that the NOXconcentration signal required for the identification of the type of diesel fuel combusted by the diesel ICE may be manipulated by the engine aftertreatment system.

[0025] The diesel engine system may include a pressure sensor arranged at the exhaust line. The electronic control unit may be configured to fine tune the fuel specific characteristic value based on the pressure determined by the pressure sensor.

[0026] The pressure may be determined between the diesel ICE and the engine aftertreatment system. Thus, the pressure of the exhaust gas as vented by the diesel ICE before entering the engine aftertreatment system can be determined. As temperature and volume, pressure is a parameter to define the state of gas, here the exhaust gases. Depending on the type of diesel fuel, a different pressure may be measured when the corresponding diesel fuel is combusted. The pressure of alternative diesel fuel may be slightly lower compared to fossil diesel fuel. Hence, the pressure may be a useful indicator to identify the type of the combusted diesel fuel.

[0027] The diesel engine system may also include a temperature sensor arranged at the exhaust line. The electronic control unit may be configured to fine tune the fuel specific characteristic value based on the temperature determined by the temperature sensor.

[0028] The temperature may be determined between the diesel ICE and the engine aftertreatment system. Thus, the temperature of the exhaust gas as vented by the diesel ICE before entering the engine aftertreatment system can be determined. As pressure and volume, temperature is a parameter to define the state of gas, here the exhaust gases. Depending on the type of diesel fuel, a different temperature may be measured when the corresponding diesel fuel is combusted. The temperature of alternative diesel fuel may be slightly lower compared to fossil diesel fuel. Hence, the temperature may be a useful indicator to identify the type of the combusted diesel fuel.

[0029] The diesel engine system may also include a catalytic converter coupled to the exhaust line.

[0030] The catalytic converter may be part of the engine aftertreatment system and comprise at least one of a diesel oxidation catalyst (DOC catalyst), a diesel particulate filter (DPF), aDocket No. 25001 / WOdiesel exhaust fluid (DEF) injector and a SCR catalyst. The catalytic converter may reduce the NOx concentration in the exhaust gases. Since the NOXconcentration may be a useful parameter to identify the type of diesel fuel combusted by the diesel ICE, the NOXsensor is arranged in front of the catalytic converter before the exhaust gases enter the catalytic converter to avoid a manipulation of the NOXconcentration signal. The diesel particulate filter may reduce particulate matter that passes to the atmosphere from the diesel ICE, reducing pollutants from the engine aftertreatment system.

[0031] The electronic control unit may be configured to determine the fuel specific characteristic value (FSCV) as an alternative diesel fuel related fuel specific characteristic value if a shorter ignition delay, a lower cylinder pressure rise, an earlier acoustic signal timing, a lower peak cylinder temperature, a lower concentration of NOX, and / or a lower exhaust gas temperature has been detected.

[0032] The shorter ignition delay and the earlier acoustic signal timing can be detected by the electronic control unit based on the knocking signal provided by the knock sensor. The lower concentration of NOXcan be detected by the electronic control unit based on the NOXconcentration signal provided by the NOXsensor. The lower cylinder pressure rise can be detected by the electronic control unit based on the exhaust pressure signal provided by the pressure sensor. The lower peak cylinder temperature can be detected by the electronic control unit based on the exhaust temperature signal provided by the temperature sensor. Hence, the type of diesel fuel combusted by the engine can be determined by the electronic control unit based on a combination of the knocking signal and the NOXconcentration signal. The exhaust temperature signal and / or the exhaust pressure signal may be used by the electronic control unit as additional parameters to distinguish the combustion of alternative diesel fuel from fossil diesel fuel, for example if the combination of the knocking signal and the NOXconcentration signal does not provide an unambiguous result of the diesel fuel type detection. Hence, the fuel specific characteristic value may be representative for alternative diesel fuel if at least one of the aforementioned parameters or operational states can be detected. Otherwise, the electronic control unit may determine a fuel specific characteristic value representative for fossil diesel fuel.

[0033] The diesel engine system may include an ambient temperature sensor to determine an ambient temperature. The electronic control unit may be configured to correct the NOXconcentration signal based on the ambient temperature.Docket No. 25001 / WO

[0034] The NOx sensor may drift slightly in dependence of the ambient temperature. But the drift may be compensated by the electronic control unit based on the ambient temperature provided by the ambient temperature sensor.

[0035] The electronic control unit may include an ECU temperature sensor to determine a temperature of the electronic control unit. The electronic control unit may be configured to correct the NOXconcentration signal based on the temperature of the electronic control unit.

[0036] Optionally, the temperature dependent drift of the NOXsensor may be compensated by the electronic control unit based on temperature provided by the ECU temperature sensor. The ECU temperature may be used if the ambient temperature is not available.

[0037] The diesel engine system may include an ambient humidity sensor to determine an ambient humidity. The electronic control unit is configured to correct the NOXconcentration signal based on the ambient humidity.

[0038] The NOXsensor may drift slightly in dependence on the ambient humidity. But the drift may be compensated by the electronic control unit based on the ambient humidity provided by the ambient humidity sensor. Hence, the electronic control unit may use the signals provided by the ambient temperature sensor and / or the ambient humidity sensor to provide an exact measurement of the NOXconcentration by the NOXsensor.

[0039] Optionally, the electronic control unit may additionally consider sensor signals of at least one pressure sensor or temperature sensor installed in an exhaust line of the internal combustion engine before and / or after a turbine of a turbocharger. For example, the corresponding sensor signals may be provided by one of so-called p3-, t3-, p4, and / or t4-sensor. Hence, heat release profiles could also be considered by the electronic control unit for the detection of the type of the diesel fuel combusted by the diesel ICE since the heat release profiles may also be different for fossil diesel fuel and alternative diesel fuel.

[0040] The electronic control unit may be configured to receive a validation value, compare the fuel specific characteristic value with the validation value, and confirm the fuel specific characteristic value based on the validation value.

[0041] For example, the electronic control unit may receive the validation value from an external entity such as a fuel station. The validation value may be (automatically) transferred from the external entity when the agricultural machine is refueled. The validation value may correspond to a fuel specific characteristic value of the fuel the agricultural machine is refueled with. Moreover, the electronic control unit may receive the validation value as a manual inputDocket No. 25001 / WOfrom the operator of the agricultural machine. Hence, the validation value may be used for double proofing the detected type of diesel fuel.

[0042] The diesel engine system may also include a fuel tank for storing diesel fuel, and a fuel sensor configured to determine the type of the diesel fuel stored in the fuel tank in terms of a validation value.

[0043] The fuel sensor may determine a validation value that corresponds to a fuel specific characteristic value of the fuel injected into the diesel ICE. The electronic control unit may compare the validation value provided by the external entity or the fuel sensor with the fuel specific characteristic value and determine a deviation. The electronic control unit may tolerate a minor deviation, for example up to 10%. But greater deviations (over 10%) may be considered as a failure and the electronic control unit may alert the operator of the agricultural machine or initiate other actions.

[0044] The electronic control unit may be configured to detect a stable running of the diesel ICE.

[0045] The diesel ICE may be considered to run stable if at least one of the operation parameters affecting the combustion such as coolant temperature of the diesel ICE, the boost pressure and the boost temperature, injection timing, etc. are in an acceptable range in respect of a reference fueling level (mg / stroke), and / or if the load is stable. The electronic control unit may await a stable running of the diesel ICE before the fuel specific characteristic value is determined. Moreover, the electronic control unit may additionally require the diesel ICE running with low idle speed. The stable running may be forced by the operator of the agricultural machine. The stability could be confirmed by the electronic control unit separately by a comparison and calculation check procedure.

[0046] The electronic control unit may be configured to adjust settings of the diesel ICE for an improved operation with alternative diesel fuel if alternative diesel fuel has been detected.

[0047] For example, the electronic control unit may adjust at least one of the point of time of injecting diesel fuel into the diesel ICE (start of injection), the amount of injected diesel fuel, the amount of air induced into the diesel ICE, the amount of exhaust gas recirculated into the diesel ICE, the idle speed may be reduced, etc. As a result of the adjustment, the emissions of harmful pollutants and / or diesel fuel consumption may be reduced.

[0048] The diesel engine system may include an engine aftertreatment system as mentioned above. The electronic control unit may be configured to adjust settings of the engineDocket No. 25001 / WOaftertreatment system for an improved operation with alternative diesel fuel if alternative diesel fuel has been detected.

[0049] For example, a regeneration interval for the engine aftertreatment system can be adjusted to safe diesel fuel.

[0050] The electronic control unit may be configured to adjust settings of the diesel ICE and / or the engine aftertreatment system for an improved operation with fossil diesel fuel if fossil diesel fuel has been detected.

[0051] Since optimized settings of the diesel ICE for operating with alternative diesel fuel may not provide the advantages as mentioned above when the diesel ICE runs with fossil diesel fuel, the electronic control unit may adjust the settings of the diesel ICE for an optimized operation with fossil diesel fuel. The electronic control unit may switch between the optimized setting for alternative diesel fuel and the optimized setting for fossil diesel fuel in dependence of the type of diesel fuel (the fuel specific characteristic value) detected by electronic control unit. Hence, the optimal setting of the diesel ICE may be selected dependent on the detected type of diesel fuel combusted by the diesel ICE.

[0052] The electronic control unit may be configured to generate a record of combusting alternative diesel fuel and store the record to a memory.

[0053] The record may be stored in the memory of the electronic control unit. The information about the usage of alternative diesel fuel can be restored from the memory for statistical use and / or later use for adjusting the diesel ICE and / or the engine aftertreatment system. For example, the electronic control unit may calculate the fuel savings, the reduction of emissions, etc. for a specific time period or for a specific field operation executed by the agricultural machine in the agricultural field. The record may also be used to refine the fuel specific reference value (FSRV).

[0054] Another aspect includes a method of determining a diesel fuel type for a diesel engine system. The method comprises steps for receiving a knocking signal from a knock sensor, receiving a NOXconcentration signal from a NOXsensor, determining a fuel specific characteristic value based on the knocking signal and the NOXconcentration signal, determining a fuel specific reference value, comparing the fuel specific characteristic value with the fuel specific reference value, and determining whether the combusted diesel fuel is fossil diesel fuel or alternative diesel fuel.Docket No. 25001 / WO

[0055] As disclosed above, the electronic control unit is configured to execute different actions. Each action may be implemented as one or more method steps of the method executable by the electronic control unit. Hence, each action for which the electronic control unit is configured to execute may be defined as a method step.

[0056] Within the scope of this application, it should be understood that the various aspects, embodiments, examples and alternatives set out herein, and individual features thereof may be taken independently or in any possible and compatible combination. Where features are described with reference to a single aspect or embodiment, it should be understood that such features are applicable to all aspects and embodiments unless otherwise stated or where such features are incompatible.BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Several aspects of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0058] FIG. 1 illustrates an agricultural machine.

[0059] FIG. 2 illustrates a schematic of a diesel engine system.

[0060] FIG. 3 illustrates a flow chart.DETAILED DESCRIPTION

[0061] FIG. 1 shows an example of an agricultural machine 100. The agricultural machine 100 may be a vehicle or a vehicle-implement combination. The vehicle may generate a tractive force to tow the implement through an agricultural field. The implement may be fixed to the vehicle or detachably connected with the vehicle. The vehicle may be an agricultural vehicle such as a tractor, a harvester, a combine, a sprayer or of any other type such as a truck. The implement may be used for an operation in the agricultural field and may be of the type of a plough, a rake, a planter, a sprayer, a mower, a trailer, etc. Depending on the type of the implement, the implement may comprise one or more tools such as a rake rotor, a mower knife, a seeding unit, a spray nozzle, a shovel, a dumper, etc.

[0062] A diesel engine system 101, as shown in more detail in FIG. 2, is integrated in the agricultural machine 100. An ambient temperature sensor 102 for sensing an ambient temperature of the agricultural machine 100 and an ambient humidity sensor 103 for sensing aDocket No. 25001 / WOhumidity of the environment of the agricultural machine 100 are also parts of the diesel engine system 101 and are attached to the agricultural machine 100.

[0063] FIG. 2 is a simplified schematic of the diesel engine system 101 of the agricultural machine 100. The diesel engine system 101 comprises a diesel internal combustion engine (ICE) 201, a fuel tank 221 with an integrated fuel sensor 222, an electronic control unit (ECU) 210, a NOx sensor 209, a pressure sensor 219, a temperature sensor 220 and an engine aftertreatment system (EAT) 202 with a catalytic converter 203, a diesel exhaust fluid (DEF) tank 207 and a DEF injector 208, as well as the ambient temperature sensor 102 and the ambient humidity sensor 103 as also shown in FIG. 1.

[0064] The fuel tank 221 can be filled with fossil diesel fuel or alternative diesel fuel or a mixture of fossil and alternative diesel fuel. The fuel tank 221 may optionally comprise a fuel sensor 222 for determining the type of the diesel fuel stored in the fuel tank 221. For example, the fuel sensor 222 may detect whether the fuel tank 221 is filled with fossil diesel fuel, any type of an alternative diesel fuel or a mixture of fossil diesel fuel with an alternative diesel fuel. The fuel tank 221 is connected with the diesel ICE 201 via a line to supply the diesel ICE 201 with diesel fuel.

[0065] The diesel ICE 201 has a cylinder block, a knock sensor 213 and an exhaust line 211. The exhaust line 211 is attached to an output A of the diesel ICE 201 and an input B of the catalytic converter 203 for providing a fluid communication of the diesel ICE 201 with the engine aftertreatment system 202 via the exhaust line 211. The exhaust line 211 between the diesel ICE 201 and the catalytic converter 203 may be formed by any suitable means, for example a tube or conventional exhaust pipe constructed from mild steel or stainless steel. The exhaust line 211 may optionally be ceramic-coated to provide better thermodynamic (e. g., insulative) properties. The exhaust gases are expelled from of the cylinders of the diesel ICE 201 in the exhaust line 211 and vented to the atmosphere at the output D of the tail pipe 214 after passing through the engine aftertreatment system 202. Arrow X indicates the direction of flow of the exhaust gases through the engine aftertreatment system 202, from upstream to downstream.

[0066] The knock sensor 213 is attached to the cylinder block of the diesel ICE 201 and may detect abnormal vibrations and sounds in the cylinders, known as “knocking” or “pinging”. Knocking may typically occur when a mixture of petrol (gasoline) and air in the cylinders of an Otto engine ignites prematurely. But knocking may also occur when alternative diesel fuels areDocket No. 25001 / WOcombusted in a diesel ICE. In such a case, the knock sensor 213 detects different acceleration signal profiles in the cylinder block of the diesel ICE 201 in dependence of the type of the alternative diesel fuel. In response thereof, the knock sensor 213 generates a corresponding knocking signal which may be a bypass filtered acceleration amplitude as a function of a crank angle of the diesel ICE 201.

[0067] The NOx sensor 209, the pressure sensor 219 and temperature sensor 220 are each situated in the exhaust line 211 between the output A and input B to measure N0xconcentration, the pressure and the temperature of the exhaust gases flowing in the exhaust line 211 upstream of the DEF injector 208. The temperature sensor 220 is of any suitable type, such as a thermocouple. That is, the sensors 209, 219 and 220 are used for measurements of exhaust gases as they exit the diesel ICE 201 and before they enter the catalytic converter 203.Optionally, further such kind of sensors may be positioned throughout the engine aftertreatment system 202.

[0068] When having passed the exhaust line 211, the exhaust gases enter the catalytic converter 203 at the input B. The catalytic converter 203 of the engine aftertreatment system 202 may comprise a diesel oxidation catalyst (DOC) 204, a diesel particulate filter (DPF) 205, a selective catalytic reduction (SCR) catalyst 206, an ammonia oxidation catalyst (AOC), or any combination of the aforementioned filters and catalyst types. As exemplarily shown in FIG.2, the catalytic converter 203 comprises a DOC 204, a DPF 205 and a SCR catalyst 206. The DOC catalyst is positioned upstream of the upstream SCR catalyst 206. The DOC 204 and the SCR catalyst 206 are connected to each other by means of a conduit 212. The conduit 212 may be of any conventional design. The DPF 205 may for instance be situated downstream of the DOC 204. A tail pipe 214 is attached to an output C of the catalytic converter 203.

[0069] The DOC 204 may be coated with precious metals such as platinum or palladium. As exhaust gases pass through the DOC 204, chemical reactions provide an oxidation of harmful pollutants such as carbon monoxide (CO) and hydrocarbons (HC) into less harmful substances as carbon dioxide (CO2) and water (FEO). Additionally, the DOC 204 may reduce soluble organic fraction (SOF) of particulate matter (PM), which is composed of unburned fuel. The DPF 205 is used for particulate matter treatment.

[0070] The DEF tank 207 and the DEF injector 208 are also parts of the engine aftertreatment system 202. The DEF tank 207 is provided as a reservoir for a source of NEE for reduction of NOx. Commonly, a urea solution is used as a dosing agent for the engine aftertreatment systemDocket No. 25001 / WO202. But another source of NH3 such as anhydrous ammonia could also be used instead of urea. The DEF injector 208 is attached to the conduit 212 and in fluid communication with the DEF tank 207 via a line for injecting urea solution in the conduit 212. The DEF injector 208 is of suitable type and is provided to dose (i.e., treat) the exhaust gases in the engine aftertreatment system 202 with a urea solution (or any other source of NH3) from the DEF tank 207. The DEF injector 208 is provided in the conduit 212 upstream of the SCR catalyst 206 such that urea solution can be administered to the exhaust gases prior to entering the SCR catalyst 206. The exhaust gases, now enriched with NH3, pass into the SCR catalyst 206. In the SCR catalyst 206, a chemical reduction reaction takes place to reduce the NOXcontent in the exhaust gases, whereby the NH3 (ammonia, which is formed by hydrolysis of the urea) reacts with the NOxto convert some of the NOxto H2O (water), N2 (nitrogen gas), and optionally CO2 (carbon dioxide).

[0071] Exhaust gases exit the catalytic converter 203 at output C and enter the tail pipe 214. At an output D of the tail pipe 214, the exhaust gases are vented to the atmosphere.

[0072] FIG. 2 shows also the electronic control unit 210 in more detail. The electronic control unit 210 comprises an I / O interface 217, a controller 215, an ECU temperature sensor 218 and a memory 216. The I / O interface 217, the controller 215 and the memory 216 may be attached to a printed circuit board (PCB). The electronic control unit 210 may receive and send signals or data via the I / O interface 217. The I / O interface 217 may be a wireless interface or a connector. As can be seen in FIG. 2, the I / O interface 217 is connected with several devices as the diesel ICE 201, the fuel sensor 222, the knock sensor 213, the pressure sensor 219, the NOXsensor 209, the temperature sensor 220, the DEF injector 208, the ambient temperature sensor 102 and the ambient humidity sensor 103. The electronic control unit 210 may be connected with additional components, e. g. of the engine aftertreatment system 202, and may receive signals from or send signals (e. g. control commands) to each component. The controller 215 may store the data or signals received by the electronic control unit 210 in the memory 216. The ECU temperature sensor 218 senses the temperature of the controller 215. The memory 216 may contain additional data or executable computer program products, for example in terms of a computer-implemented method, that may be retrieved, processed or executed by the controller 215. Data or signals resulting from the processing of data or signals or from the execution of a computer program product may be stored to the memory 216 or sent to the I / O interface 217 by the controller 215. The memory 216 could also be provided by a cloud storage. Regardless ofDocket No. 25001 / WOFIG. 2 exemplarily illustrating the electronic control unit 210 as a standalone electronic control unit, the electronic control unit 210 may represent a network of multiple electronic control units distributed within the system.

[0073] FIG. 3 shows a flow chart of a method for determining a diesel fuel type. The method may be at least partly a computer-implemented method stored as a computer program product in the memory 216 of the electronic control unit 210. The electronic control unit 210 is configured to carry out the method. Computer-implemented parts of the method may be executed by the controller 215 of the electronic control unit 210. Non-computer-implemented parts of the method may be executed manually or by other components of the system. The method is described by way of example of several acts without any restriction in respect of the acts. That is, the number or the order of acts may be adapted, for example single acts may be excluded and / or added and executed earlier or later than described. The method starts at act SI 00 and proceeds to act SI 01.

[0074] At act SI 01, the ignition of the diesel ICE 201 is started. For example, an operator of the agricultural machine 100 may activate the ignition manually or press a start button for sending a signal to the electronic control unit 210 to start the ignition.

[0075] Then, the diesel ICE 201 is provided with diesel fuel stored in the fuel tank 221. The diesel fuel may be fossil diesel fuel, alternative diesel fuel, for example any type of a paraffinic diesel fuel, or a mixture of fossil and alternative diesel fuel. The difference between fossil and alternative diesel fuel has been explained above in the background section of this disclosure. The diesel ICE 201 burns the diesel fuel (regardless if it is fossil diesel fuel, alternative diesel fuel or a mixture thereof) with atmospheric air to generate a drive torque. The drive torque can be used to propel the agricultural machine 100 and to drive any auxiliaries of the agricultural machine 100 such as a generator that produces electrical power (e. g. for charging a battery) or a pump to provide a hydraulic fluid to a hydraulic actuator of the agricultural machine 100. Due to the combustion process, the diesel ICE 201 produces waste gases, commonly being known as exhaust gases and expels them into the exhaust line 211. The exhaust gases are rich in NOXand other particulate matter.

[0076] The method proceeds to step SI 01 and the electronic control unit 210 checks whether the diesel ICE 201 is running stable. For example, the electronic control unit 210 may check whether the coolant temperature of the diesel ICE 201, the boost pressure and the boostDocket No. 25001 / WOtemperature are each in an acceptable range in respect of a reference fueling level (mg / stroke), and whether the load is stable.

[0077] If the diesel ICE 201 is not running stable, the method proceeds to step SI 02 to await a stable running of the diesel ICE 201. Additionally, the electronic control unit 210 can also advise the operator of the agricultural machine 100 to temporarily set a constant engine speed for an engine state (load) stabilization. After step SI 02, the method jumps back to step SI 01. If the diesel ICE 201 is running stable, the method proceeds to step SI 03.

[0078] At step SI 03, the knock sensor 213 may generate a knocking signal if knocking of the diesel ICE 201 due to the combustion of the diesel fuel has been detected. The NOXsensor 209 determines the NOXconcentration of the exhaust gases in the exhaust line 211 and generates a corresponding NOXconcentration signal. The ambient temperature sensor 102 determines the ambient temperature of the environment of the agricultural machine 100 and generates a corresponding ambient temperature signal. The ambient humidity sensor 103 determines the ambient humidity of the environment of the agricultural machine 100 and generates a corresponding ambient humidity signal. Then, the electronic control unit 210 receives any knocking signals provided by the knock sensor 213, the NOXconcentration signal provided by the NOXsensor 209, the ambient temperature signal provided by the ambient temperature sensor 102 and the ambient humidity signal provided by the ambient humidity sensor 103.

[0079] The method proceeds to step SI 04 and the electronic control unit 210 corrects the NOXconcentration signal by means of the received ambient temperature signal and / or the ambient humidity signal. The electronic control unit 210 may apply predefined formulas to calculate the corrected values.

[0080] The method proceeds to step SI 05 and the electronic control unit 210 determines a fuel specific characteristic value (FSCV) of the diesel fuel combusted by the diesel ICE 201 based on the knocking signal and the NOXconcentration signal. The fuel specific characteristic value is a value representative for the type of diesel fuel combusted by the diesel ICE 201 which can be used by the electronic control unit 210 to determine the type of diesel fuel combusted by the diesel ICE 201. The memory 216 of the electronic control unit 210 may contain a reference for determining the fuel specific characteristic value in dependence of the knocking signal and the (corrected) NOXconcentration signal. The reference may be a look-up table or a characteristic curve map with knocking signal curves (values) and NOXconcentration signal curves (values) representative for the different types of diesel fuels assigned to different fuel specificDocket No. 25001 / WOcharacteristic values. Based thereon, the electronic control unit 210 may determine the fuel specific characteristic value of the diesel fuel combusted by the diesel ICE 201, for example by comparing the knocking signal with the knocking signal curves and comparing the (corrected) NOx concentration signal with the NOXconcentration signal curve. Alternatively, the memory 216 may comprise an algorithm to calculate the fuel specific characteristic value of the diesel fuel combusted by the diesel ICE 201 based on the knocking signal and the NOXconcentration signal. The electronic control unit 210 may determine the fuel specific characteristic value based on one out of the knocking signal and the NOXconcentration signal only. For example, the (corrected) NOXconcentration signal of alternative diesel fuel may show a lower level compared to fossil diesel. But the determination of the fuel specific characteristic value based on both the knocking signal and the NOXconcentration signal in combination may provide much better accuracy.

[0081] The method proceeds to step SI 06 and the temperature sensor 220 determines the temperature of the exhaust gases in the exhaust line 211 and generates a corresponding exhaust temperature signal. Additionally, the pressure sensor 219 determines the pressure of the exhaust gases in the exhaust line 211 and generates a corresponding exhaust pressure signal. Then, the electronic control unit 210 receives the exhaust temperature signal from the temperature sensor 220 and the exhaust pressure signal from the pressure sensor 219.

[0082] The method proceeds to step SI 07 and the electronic control unit 210 fine tunes the fuel specific characteristic value by means of the exhaust temperature signal and / or the exhaust pressure signal. In case of certain conditions, the exhaust temperature signal and / or the exhaust pressure signal may be needed to distinguish precisely a type of diesel fuel from another type. The memory 216 of the electronic control unit 210 may contain a look-up table or a characteristic curve map with exhaust temperature signal curves and exhaust pressure signal curves representative for the different types of diesel fuels. For example, exhaust gas temperatures seem to be a bit lower for alternative diesel fuels compared to fossil diesel fuel. Based thereof, the electronic control unit 210 may fine tune the fuel specific characteristic value of the diesel fuel combusted by the diesel ICE 201. Alternatively, the memory 216 may comprise an algorithm to fine tune the fuel specific characteristic value of the diesel fuel combusted by the diesel ICE 201 based on the knocking signal and the NOXconcentration signal. Hence, the fuel specific characteristic value determined at step SI 05 may be adjusted or changed.Docket No. 25001 / WO

[0083] Depending on the detected parameters by the different sensors, the electronic control unit 210 determines a fuel specific characteristic value that relates more to fossil diesel fuel or to (any type of) alternative diesel fuel. The fuel specific characteristic value may relate more to alternative diesel fuel if an earlier acoustic signal timing (by the knock sensor 213), a shorter ignition delay (by the knock sensor 213), a lower cylinder pressure rise, a lower peak cylinder temperature, a lower concentration of NOX(by the NOXsensor 209) and / or a lower exhaust gas temperature (by the temperature sensor 220) has been detected.

[0084] The method proceeds to step SI 08 and fuel specific reference values (FSRV) each assigned to a specific type of diesel fuel are provided to the electronic control unit 210.According to a more general approach for example, a first fuel specific reference value is assigned to fossil fuel and a second reference value is assigned to alternative fuel. According to a more specific approach for example, a first fuel specific reference value is assigned to fossil fuel, a second fuel specific reference value is assigned to GtL diesel fuel, a third fuel specific reference value is assigned to eDiesel fuel and a fourth fuel specific reference value is assigned to HVO diesel fuel wherein the values of the first to fourth fuel specific reference values are all different. Additional fuel specific reference values may be assigned to other types of diesel fuel. The fuel specific reference values may be stored in the memory 216 from which the electronic control unit 210 may receive the values to determine the fuel specific reference values.

[0085] The method proceeds to step SI 09 and the electronic control unit 210 compares the determined fuel specific characteristic value (FSCR) with the fuel specific reference values (FSRV) to check which one of the fuel specific reference values is closest to the determined fuel specific characteristic value. Based on this comparison, the electronic control unit 210 determines the type of diesel fuel combusted by the diesel ICE 201, e. g. fossil diesel fuel or any type of the alternative diesel fuels. Alternatively (for a less complex method), the electronic control unit 210 compares the fuel specific characteristic value with the fuel specific reference value assigned to fossil diesel fuel only to check whether the determined fuel specific characteristic value is representative for fossil diesel fuel or not.

[0086] The method may optionally proceed to step SI 10. At step SI 10, the optional available fuel sensor 222 may determine the type of the diesel fuel stored in the fuel tank 221 and generate a validation value in accordance with the type of the diesel fuel stored in the fuel tank 221. The electronic control unit 210 may receive the validation value and compare the fuelDocket No. 25001 / WOspecific characteristic value with the validation value to check whether the determined type of diesel fuel based on the fuel specific characteristic value complies with the type of diesel fuel stored in the fuel tank 221. The electronic control unit 210 may confirm the fuel specific characteristic value if it is in accordance with the validation value. If not, a component of the diesel engine system 101 used for determination of the fuel specific characteristic value may have a defect, for example. In such a case, the electronic control unit 210 may send a warning message to an operator of the agricultural machine 100. Alternatively, the fuel type signal may be provided by a device different to the fuel sensor 222. For example, a user may enter the fuel type or a fuel dispenser may automatically send a corresponding signal to the electronic control unit 210 when the agricultural machine 100 is refueled which may be stored in the memory 216.

[0087] The method proceeds to step Sill and the electronic control unit 210 checks whether fossil diesel fuel or alternative diesel fuel has been detected. If the determined fuel specific characteristic value is representative for fossil diesel fuel (closest to the fuel specific reference value assigned to fossil diesel fuel), a combustion of fossil diesel fuel in the diesel ICE 201 has been detected and the method proceeds with step SI 13. Otherwise, alternative diesel fuel has been detected and the method proceeds with step SI 12.

[0088] At step SI 12, in response to the detected alternative diesel fuel, the electronic control unit 210 adjusts settings and / or the control of the diesel ICE 201 and / or the engine aftertreatment system 202 for an optimized operation with alternative diesel fuel. The optimization may optionally depend on specific properties of the type of the alternative diesel fuel, e. g. GtL diesel fuel, PtX diesel fuel (eDiesel) or HVO diesel fuel. The optimization may improve performance of the diesel ICE 201 and / or the engine aftertreatment system 202, reduce fuel consumption, and prevent potential damage of the diesel engine system 101. For example, alternative diesel fuel may ignite easier and faster (shorter ignition delay) compared to fossil diesel fuel causing different cylinder pressures and heat release. Hence, the electronic control unit 210 may adjust the control of the diesel ICE 201 to advance the start of injection (and / or ignition) 1 to 2 crank degrees, for example. Due to the earlier injection (and / or ignition), fuel consumption and CO2 emissions may be reduced. The electronic control unit 210 may also lengthen the regeneration interval of the engine aftertreatment system 202 to save diesel fuel. As long as combustion of alternative diesel fuel is determined, the electronic control unit 210 may generate a record of combusting alternative diesel fuel and store the record to the memoryDocket No. 25001 / WO216. The information about the usage of alternative diesel fuel can be restored from the memory 216 for statistical use and / or later use for adjusting the diesel ICE 201 and / or the engine aftertreatment system 202.

[0089] At step SI 13, in response to the detected fossil diesel fuel, the electronic control unit 210 adjusts the diesel ICE 201 and / or the engine aftertreatment system 202 for an optimized operation with fossil diesel fuel. For example, the electronic control unit 210 may shift back the start of injection (and / or ignition) 1 to 2 crank degrees since fossil fuel may not ignite as easy and fast as alternative diesel fuel does.

[0090] After step SI 12 and SI 13, the steps SI 03 to SI 12 / S113 may be repeated until the diesel ICE 201 has been shut down. After shut down of the diesel ICE 201, the method proceeds to step SI 14.

[0091] At step SI 14, the method ends. The method may be restarted again with step SI 00.

[0092] All references cited herein are incorporated herein in their entireties. If there is a conflict between definitions herein and in an incorporated reference, the definition herein shall control.LISTING OF DRAWING ELEMENTS100 agricultural machine 206 SCR catalyst101 diesel engine system 207 DEF tank102 ambient temperature sensor 208 DEF injector103 ambient humidity sensor 209 NOXsensor201 diesel ICE 210 electronic control unit202 engine aftertreatment system 211 exhaust line203 catalytic converter 212 conduit204 DOC 213 knock sensor205 DPF 214 tail pipeDocket No. 25001 / WO controllermemoryI / O interfaceECU temperature sensorpressure sensortemperature sensorfuel tankfuel sensor

Claims

Docket No. 25001 / GBPCLAIMSWhat is claimed is:

1. A diesel engine system (101) for an agricultural machine (100), comprising:A diesel internal combustion engine (ICE) (201) configured to combust fossil diesel fuel and alternative diesel fuel;a knock sensor (213) integrated in the diesel internal combustion engine (201);a NOx sensor (209); andan electronic control unit (210); whereinthe electronic control unit (210) is configured toreceive a knocking signal from the knock sensor (213);receive a NOXconcentration signal from the NOXsensor (209);determine a fuel specific characteristic value based on the knocking signal and the NOXconcentration signal;determine a fuel specific reference value;compare the fuel specific characteristic value with the fuel specific reference value; anddetermine whether the combusted diesel fuel is fossil diesel fuel or alternative diesel fuel.

2. The diesel engine system (101) of claim 1, whereinthe diesel ICE (201) comprises an exhaust line (211); andthe NOXsensor (209) is arranged at the exhaust line (211).

3. The diesel engine system (101) of claim 1 or 2, comprising:a pressure sensor (219) arranged at the exhaust line (211); whereinthe electronic control unit (210) is configured tofine tune the fuel specific characteristic value based on the pressure determined by the pressure sensor (219).

4. The diesel engine system (101) of claim 2 or 3, comprising:a temperature sensor (220) arranged at the exhaust line (211); whereinthe electronic control unit (210) is configured toDocket No. 25001 / GBPfine tune the fuel specific characteristic value based on the temperature determined by the temperature sensor (220).

5. The diesel engine system (101) of any one of claims 2 to 4, comprising:a catalytic converter (203) coupled to the exhaust line (211).

6. The diesel engine system (101) of any one of the preceding claims, whereinthe electronic control unit (210) is configured to determine the fuel specific characteristic value as an alternative diesel fuel related fuel specific characteristic value if a shorter ignition delay,a lower cylinder pressure rise;an earlier acoustic signal timing;a lower peak cylinder temperature;a lower concentration of NOX; and / ora lower exhaust gas temperaturehas been detected.

7. The diesel engine system (101) of any one of the preceding claims, comprising:An ambient temperature sensor (102) to determine an ambient temperature; wherein the electronic control unit (210) is configured tocorrect the NOXconcentration signal based on the ambient temperature.

8. The diesel engine system (101) of any one of the preceding claims, whereinthe electronic control unit (210) comprises an ECU temperature sensor (218) to determine a temperature of the electronic control unit (210); whereinthe electronic control unit (210) is configured tocorrect the NOXconcentration signal based on the temperature of the electronic control unit (210).

9. The diesel engine system (101) of any one of the preceding claims, comprising:An ambient humidity sensor (103) to determine an ambient humidity; wherein the electronic control unit (210) is configured tocorrect the NOXconcentration signal based on the ambient humidity.

10. The diesel engine system (101) of any one of the preceding claims, whereinDocket No. 25001 / GBPthe electronic control unit (210) is configured toreceive a validation value; andcompare the fuel specific characteristic value with the validation value; and confirm the fuel specific characteristic value based on the validation value.

11. The diesel engine system (101) of claim 10, comprising:A fuel tank (221) for storing diesel fuel; anda fuel sensor (222) configured to determine the type of the diesel fuel stored in the fuel tank (221) in terms of a validation value.

12. The diesel engine system (101) of any one of the preceding claims, whereinthe electronic control unit (210) is configured to detect a stable running of the diesel ICE (201).

13. The diesel engine system (101) of any one of the preceding claims, whereinthe electronic control unit (210) is configured to adjust settings of the diesel ICE (201) for an improved operation with alternative diesel fuel if alternative diesel fuel has been detected.

14. The diesel engine system (101) of any one of the preceding claims, comprising:An engine aftertreatment system (202); whereinthe electronic control unit (210) is configured to adjust settings of the engine aftertreatment system (202) for an improved operation with alternative diesel fuel if alternative diesel fuel has been detected.

15. The diesel engine system (101) of claim 14, whereinthe electronic control unit (210) is configured to adjust settings of the diesel ICE (201) and / or the engine aftertreatment system (202) for an improved operation with fossil diesel fuel if fossil diesel fuel has been detected.

16. The diesel engine system (101) of any one of the preceding claims, whereinthe electronic control unit (210) is configured to generate a record of combusting alternative diesel fuel and store the record to a memory (216).

17. A method of determining a diesel fuel type for a diesel engine system (101), comprising:receiving a knocking signal from a knock sensor (213);Docket No. 25001 / GBPreceiving a NOXconcentration signal from a NOXsensor (209); determining a fuel specific characteristic value based on the knocking signal and the NOXconcentration signal;determining a fuel specific reference value;comparing the fuel specific characteristic value with the fuel specific reference value; anddetermining whether the combusted diesel fuel is fossil diesel fuel or alternative diesel fuel.

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