Method for onboard monitoring of emissions in a commercial vehicle

Abstract

The invention relates to a method for onboard monitoring of emissions in a commercial vehicle, wherein the method is implemented in an electronic control unit of the commercial vehicle, wherein a calculation of a moving average of an emission species is performed, wherein a plurality N of accumulators (ΣNOX) are used to accumulate emission values ​​from an input vector (NOXtp, NH3tp) detected during the journey of the commercial vehicle, wherein a first accumulator (ΣNOX) accumulates the emission values ​​of the input vector (NOXtp, NH3tp) from the beginning of a journey until the work (W) performed by the commercial vehicle since the beginning of this accumulation corresponds to a predetermined reference work (W_ref), wherein after each Nth of the reference work (W_ref) a further accumulator (ΣNOX) accumulates the emission values ​​of the input vector (NOXtp, NH3tp).until the work (W) performed by the commercial vehicle since the start of this accumulation corresponds to the specified reference work (W_ref), wherein the emission values ​​(NOX MAW) accumulated by the accumulators (ΣNOX) are categorized into a vector (V) which has a number of elements with emission value ranges (EWB) with associated emission value frequencies (EWH), wherein a sorting process is applied to the vector (V) to determine the hundredth and ninetieth percentiles (P90, P100) for each trip.

Description

[0001] The invention relates to a method for onboard monitoring of emissions in a commercial vehicle according to the preamble of claim 1.

[0002] Continuous monitoring of emissions, particularly NOx, NH3, and particulate matter, during every journey of a commercial vehicle is a necessary requirement for compliance with environmental regulations. This process, also known as onboard monitoring, involves the real-time measurement and evaluation of emissions during every journey, from engine start to engine shutdown.

[0003] To comply with legal requirements, the moving average window procedure is prescribed, which involves calculating emissions based on defined work references.

[0004] EP 3 803 076 B1 describes a method for determining a reference value for the presence of at least one substance in an exhaust stream of an internal combustion engine, wherein the at least one substance is subjected to exhaust gas treatment, the exhaust gas treatment being carried out according to the reference value, wherein: when the internal combustion engine is started and the starting of the internal combustion engine satisfies a first criterion: accumulation of the occurrence of the at least one substance downstream of the exhaust gas treatment is carried out in a first period, wherein the criterion includes a criterion by which it is determined whether the start of the internal combustion engine is to be classified as a cold start or not, and wherein it is determined whether the reference value is to be recalculated on the basis of the accumulated occurrence of the at least one substance, and the reference value is recalculated if the accumulated occurrence of the at least one substance exceeds a first limit value.

[0005] The invention is based on the objective of providing a novel method for onboard monitoring of emissions in a commercial vehicle.

[0006] The problem is solved according to the invention by a method for onboard monitoring of emissions in a commercial vehicle with the features of claim 1.

[0007] A method for onboard monitoring of emissions in a commercial vehicle is proposed, wherein the method is implemented in an electronic control unit of the commercial vehicle, and wherein a moving average of an emission species is calculated. According to the invention, a plurality N of accumulators is used to accumulate emission values ​​from an input vector detected during the journey of the commercial vehicle, wherein a first accumulator accumulates the emission values ​​of the input vector from the beginning of a journey until the work performed by the commercial vehicle since the beginning of this accumulation corresponds to a predetermined reference work, wherein after each Nth of the reference work, a further accumulator accumulates the emission values ​​of the input vector until the work performed by the commercial vehicle since the beginning of this accumulation corresponds to the predetermined reference work.wherein the emission values ​​accumulated by the accumulators are categorized into a vector which has a number of elements with emission value ranges with associated emission value frequencies, wherein a sorting process is applied to the vector to determine the hundredth and ninetieth percentiles for each trip.

[0008] The solution according to the invention enables the mapping of ISC (In Service Compliance) and emission calculation in a control unit with possible compliance with new emission control law requirements.

[0009] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0010] This shows: Fig. 1: a schematic view of a method for onboard monitoring of emissions in a commercial vehicle, Fig. 2: a schematic view of a cascaded approach compared with the time-based approach, and Fig. 3: a schematic view of a method for determining percentiles.

[0011] Corresponding parts are marked with the same reference symbols in all figures.

[0012] According to the present invention, a method for onboard monitoring of emissions in a commercial vehicle is proposed. The method can be implemented in an electronic control unit of the commercial vehicle.

[0013] In this process, cascaded accumulators ΣNOX are used to accumulate work W done by the commercial vehicle from the start of the journey until the work W done matches a predetermined reference work W_ref.

[0014] The cascaded accumulators ΣNOX are used together with a dynamic window start based on accumulated work W instead of fixed time intervals.

[0015] The procedure involves querying emission values ​​to determine percentiles P100 and P90 after a window has ended.

[0016] The percentiles P100 and P90 are categorized and a sorting process is applied to them.

[0017] The procedure ensures compliance with legal requirements and provides valuable insight into the emission performance of a commercial vehicle.

[0018] According to the present invention, a real-time calculation of the moving average of an emission species is performed with subsequent statistical determination of the percentile P100, P90 from the created data series in the control unit.

[0019] Cascaded summation blocks are provided for calculating and displaying the moving average.

[0020] Furthermore, the frequency and the magnitude of the value are represented by creating a histogram vector, followed by determining the percentile sizes.

[0021] Figure 1 This is a schematic view of a procedure for onboard monitoring of emissions in a commercial vehicle.

[0022] According to the present invention, which can be implemented as software in a control unit of a commercial vehicle, at least one input vector NOXtp, NH3tp is

[0023] Emission values ​​are used, for example for nitrogen oxide emissions, which are obtained from sensors located behind an exhaust pipe, such as NOx sensors.

[0024] An onboard monitoring unit (OBM) contains a calculation module 1 for calculating a moving average NOX_MAW, NH3_MAW from the input vector NOXtp, NH3tp. Calculation module 1 also receives an exhaust mass flow rate (MFR) and the current power output Pwr of the commercial vehicle's engine. Furthermore, the onboard monitoring unit (OBM) contains a calculation module 2 for calculating percentiles P100, P90 from the moving average NOX_MAW, NH3_MAW and a counter value WdwCtr for a number of windows. The values ​​from the individual windows are sorted (from smallest to largest) using a multi-digit vector containing the moving average NOX_MAW, NH3_MAW from calculation module 1. The respective percentiles can then be determined.Furthermore, in calculation module 2, a cumulative emission value (in mg / kWh) is determined, for example, using two summation blocks for the respective emission species and the work performed. Additionally, a calculation module 3 is located in the onboard monitoring unit (OBM). After the ignition (Z) is switched off, this module stores the emission result (mg / kWh) for each trip in non-volatile memory (e.g., EEPROM). A vector is used for this purpose, which can, for example, have ten positions to store the last ten trip results. When the last position is filled, the next trip result is written to the first position, and so on. Furthermore, a module 4 is located in the onboard monitoring unit (OBM), which can record any potential emission exceedances and forward them to other software instances.

[0025] Figure 1The onboard monitoring unit (OBM) is presented in a clear and concise manner. The subsequent "Percentile / Cumulative" module determines the 100th and 90th percentiles. This is achieved by sorting the values ​​from the individual windows (MAW Calculation) using a 50-digit vector (smallest to largest). The respective percentiles can then be determined accordingly. Furthermore, the module calculates the cumulative emission value in mg / kWh using two summation blocks for the respective species and the energy generated.

[0026] Due to limitations in computing power, the present invention deviates from the standardized, time-based approach. Instead, a new approach with a number N of, for example, 20 cascaded accumulators ΣNOX is proposed.

[0027] Figure 2 This is a schematic view of the cascaded approach compared to the time-based approach.

[0028] In the previous time-based approach, an accumulator ΣNOX begins accumulating at the start of the journey, for example, when the ignition Z is switched on, until the work done W equals the reference work W_ref, which is typically derived from the WHTC (World Harmonised Transient Cycle) exhaust gas test cycle for commercial vehicles. Once the reference work W_ref is reached, a new accumulation cycle begins.

[0029] In the inventive approach, a first accumulator ΣNOX begins accumulating data at the start of the journey, for example, when the ignition Z is switched on, until the work performed W corresponds to the reference work W_ref, which is typically derived from the WHTC (World Harmonised Transient Cycle) exhaust gas test cycle for commercial vehicles. When using N number of accumulators ΣNOX, a new window can be started by another accumulator ΣNOX after every Nth of the reference work W_ref. In the example shown, when using N number of 20 accumulators ΣNOX, a new window can be started by another accumulator ΣNOX after every twentieth of the reference work W_ref. This approach ensures that the commercial vehicle's control unit is not flooded with data and operates smoothly. Once a window is complete, it provides a value MAW_value in mg / kWh or g / kWh.

[0030] In the lower area of ​​the Figure 2 A diagram of cumulative NOX MAW emission values ​​over time t is shown. Curve K1 shows the values ​​for the method according to the invention, and curve K2 shows the values ​​for the prior art time-based method.

[0031] These values ​​are then used to determine percentiles P90 and P100.

[0032] Figure 3Figure 1 is a schematic representation of the method for determining the P90 and P100 percentiles. The cumulative NOx MAW emission values ​​are categorized into a vector V containing multiple elements. Emission ranges (EWB) with corresponding emission frequencies (EWH) are stored in vector V. A sorting process is applied to vector V to determine the hundredth and ninth percentiles (P100) for each trip. The data obtained by the inventive method can be displayed and output in ISC diagrams for in-service compliance (ISC) purposes. For example, a cumulative distribution function (CDF) can be displayed. The value from the window method (MAW) can be shown as normally distributed, with the percentiles determined after the test run. Furthermore, the percentile readings, calculated "online" by software, can be displayed in a diagram.This is a significant difference from the conventional methodology (post-test - post-processing). While the software must have a percentile value available at every point in time and does not know when the journey ends, in conventional practice the entire population of the measurement is known.

[0033] The approach according to the invention offers an efficient means of monitoring emissions with optimized use of computing power, ensures compliance with legal requirements and provides valuable insight into the emission performance of a commercial vehicle.

[0034] The inventive approach can also be used in particular with upcoming legal regulations such as Euro 7 for measurements in operation. Reference symbol list

[0035] 1 Calculation module 2 Calculation module 3 Calculation module 4 Module 100th < perc avg 100th percentile (mean) 90th < perc avg 90th percentile (mean) Cumulative emission value Cumul avg Mean of the cumulative emission EE EE range EE EE frequency K1, K2 curve MAW_value Value MFR Exhaust mass flow N Number, variety NOXtp, NH3tp Input vectors NOX MAW, NH3_MAW Cumulative emission values ​​Pwr Power P100th percentile P90th percentile OB M On-board monitoring unit t Time W Work WdwCtr Counter for window count (valid) W_ref Reference work ZZ Ignition Σ NOX Accumulator

Claims

1. Method for onboard monitoring of emissions in a commercial vehicle, wherein the method is implemented in an electronic control unit of the commercial vehicle, wherein a calculation of a moving average of an emission species is performed, characterized by the fact thatA plurality N of accumulators (ΣNOX) are used to accumulate emission values ​​recorded during the journey of the commercial vehicle from an input vector (NOXtp, NH3tp), wherein a first accumulator (ΣNOX) accumulates the emission values ​​of the input vector (NOXtp, NH3tp) from the beginning of a journey until the work (W) performed by the commercial vehicle since the beginning of this accumulation corresponds to a predetermined reference work (W_ref), wherein after each Nth of the reference work (W_ref) another accumulator (ΣNOX) accumulates the emission values ​​of the input vector (NOXtp, NH3tp) until the work (W) performed by the commercial vehicle since the beginning of this accumulation corresponds to the predetermined reference work (W_ref), wherein the emission values ​​(NOX MAW) accumulated by the accumulators (ΣNOX) are categorized into a vector (V).which has a number of elements with emission value ranges (EWB) with associated emission value frequencies (EWH), wherein a sorting process is applied to the vector (V) to determine the hundredth and ninetieth percentiles (P90, P100) for each trip.

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