Statistically supported real driving emission calibration: Using cycle generation to provide vehicle-specific and statistically representative test scenarios for Euro 7

2020 ◽  
Vol 21 (10) ◽  
pp. 1783-1799 ◽  
Author(s):  
Johannes Claßen ◽  
Stefan Pischinger ◽  
Sascha Krysmon ◽  
Stefan Sterlepper ◽  
Frank Dorscheidt ◽  
...  
Keyword(s):  
Work Load ◽  
Vehicle Group ◽  
Test Time ◽  
Test Duration ◽  
Emission Measurement ◽  
Product Portfolio ◽  
Generation Process ◽  
Real Driving Emission ◽  
Test Scenarios ◽  
Emission Legislation

The progression of emission legislation has intensified the efforts of the automotive industry to develop improved exhaust gas after-treatment systems. The requirement to fulfill Euro 6d-TEMP in real-world driving scenarios, the already significant calibration effort for Euro 6d and the Euro 7 emission standards in discussion have significantly increased the work load for calibration engineers and the requirements for testing resources. Many original equipment manufacturers are implementing taskforces in order not to have to discard the planned start of production for their products, and some are even already forced to reduce their product portfolio. This is due to the diverse testing matrix required to cover all possible real driving emissions test scenarios. One big challenge is the extension and possible variation of boundary conditions regarding ambient temperatures, traffic conditions, road gradients and other varying driving resistances. Moreover, the test duration can cause considerable differences in the measured emissions, even if the same route is driven repeatedly. Addressing these challenges makes the application of a dedicated, event-targeted emission calibration mandatory. Since only a few sequences of the time-consuming road tests are relevant for improving the emission calibration, the methodology presented in this article focuses on the exact reproduction of these emission events on an emission chassis dynamometer with the aim of implementing calibratable solutions for these events. This is done using a real driving emission-cycle-generator which creates real driving emission compliant severe test scenarios and which focuses on the statistical relevance related to the typical product specific operation. The underlying generation process accesses a large database with real driving emission measurement results focusing on vehicle- or vehicle-group-specific challenges, using statistical approaches. It will be demonstrated how this procedure reduces test time and how it helps to tackle the substantial real driving emission work-load, while providing a dependable base to achieve real driving emission legislation compliance.

Aerodynamic Drag Measurement in a High-Enthalpy Shock Tunnel

2018 ◽  
Author(s):  
Yunpeng Wang ◽  
Zonglin Jiang ◽  
Honghui Teng
Keyword(s):  
Natural Frequencies ◽  
Aerodynamic Drag ◽  
Aerodynamic Force ◽  
Mechanical Vibration ◽  
Low Frequency ◽  
Shock Tunnel ◽  
Test Time ◽  
Test Duration ◽  
Flow State ◽  
High Enthalpy

Shock tunnels create very high temperature and pressure in the nozzle plenum and flight velocities up to Mach 20 can be simulated for aerodynamic testing of chemically reacting flows. However, this application is limited due to milliseconds of its test duration (generally 500 μs–20 ms). For the force test in the conventional hypersonic shock tunnel, because of the instantaneous flowfield and the short test time [1–4], the mechanical vibration of the model-balance-support (MBS) system occurs and cannot be damped during a shock tunnel run. The inertial forces lead to low frequency vibrations of the model and its motion cannot be addressed through digital filtering. This implies restriction on the model’s size and mass as its natural frequencies are inversely proportional the length scale of the model. As to the MBS system, sometimes, the lowest natural frequency of 1 kHz is required for the test time of typically 5 ms in order to get better measurement results [2]. The higher the natural frequencies, the better the justification for the neglected acceleration compensation. However, that is very harsh conditions to design a high-stiffness MBS structure, particularly a drag balance. Therefore, it is very hard to carried out the aerodynamic force test using traditional wind tunnel balances in the shock tunnel, though its test flow state with the high-enthalpy is closer to the real flight condition.

scholarly journals The contribution of reduced COVID-19 test time in controlling the spread of the disease: A simulation-based approach

2022 ◽  
Vol 12 (2) ◽  
Author(s):  
Youness Frichi ◽  
Abderrahmane Ben Kacem ◽  
Fouad Jawab ◽  
Said Boutahari ◽  
Oualid Kamach ◽  
...  
Keyword(s):  
Discrete Event ◽  
Mass Scale ◽  
Test Time ◽  
Test Duration ◽  
Accurate Identification ◽  
Event Simulation ◽  
Simulation Results ◽  
Precautionary Measures ◽  
Novel Coronavirus ◽  
The Impact

The novel coronavirus COVID-19 has known a large spread over the globe threatening human health. Recommendations from WHO and specialists insist on testing on a mass scale. However, health systems do not have enough resources. The current process requires the isolation of testees in the hospitals’ isolation rooms for several hours until the test results are revealed, limiting hospitals’ capacities to test large numbers of cases. The aim of this paper was to estimate the impact of reducing the COVID-19 test time on controlling the pandemic spread, through increasing hospitals’ capacities to test on a mass scale. First, a discrete-event simulation was used to model and simulate the COVID-19 testing process in Morocco. Second, a mathematical model was developed to demonstrate the effect of accurate identification of infected cases on controlling the disease’s spread. Simulation results showed that hospitals’ testing capacities could be increased six times if the test duration fell from 10 hours to 10 minutes. The reduction of test time would increase testing capacities, which help to identify all the infected cases. In contrast, the simulation results indicated that if the infected population is not accurately identified and no precautionary measures are taken, the virus will continue to spread until it reaches the total population. Reducing test time is a vital component of the response to the COVID-19 pandemic. It is essential for the effective implementation of policies to contain the virus.

DEVERT®: The DEUTZ Concept to Meet the Emission Level U.S. EPA Tier 3 and EU COM 3A for Non-Road Engines

2006 ◽  
Author(s):  
Heiner Bu¨lte ◽  
Wolfgang Beberdick ◽  
Manfred Pu¨tz ◽  
Peter Kipke
Keyword(s):  
Material Handling ◽  
Industrial Applications ◽  
Product Portfolio ◽  
Pump System ◽  
Construction Machinery ◽  
Variable Valve Actuation ◽  
Wide Range ◽  
And Performance ◽  
Tier 3 ◽  
Emission Legislation

From 2006 to 2008 depending on the power ratings, Deutz has to update its complete engine product portfolio of compact engines to meet the emission legislation U.S. EPA Tier 3 and EU COM 3A for applications of mobile nonroad machinery. This challenge covers air cooled, oil cooled and as well water cooled engines up to 500 kW. To provide the best solution for the customer with respect to engine price, fuel consumption, power rating and torque characteristics. Deutz will introduce a technology concept called DEVERT® — Deutz Variable Emissions Reduction Technology. In the wide range of industrial applications of construction machinery, agriculture, material handling, and others DEVERT® provides an optimised solution for every case. The technology approach of DEVERT® consists of injection systems like the mechanical unit pump system and the Deutz Common Rail (DCR®), 2 and 4 valve cylinder-heads, different solutions for internal and external exhaust gas recirculation, and also variable valve actuation. The focus of this paper is on the water-cooled, in-line engine families 2012 and 2013 with a displacement of 4 to 7 l. Based on the application of DEVERT® to these engine families the different technologies are explained by their functionality and their impact on emissions and performance. A short outlook of the emission legislation on future technologies is given. Here exhaust after-treatment will have a significant impact on the engine package with new challenges for the variety of applications.

scholarly journals Comparison of Compass Suprathreshold Screening Strategies

2021 ◽  
Vol 10 (19) ◽  
pp. 4330
Author(s):  
Paolo Fogagnolo ◽  
Dario Romano ◽  
Giovanni Montesano ◽  
Valentino De Ruvo ◽  
Luca Mario Rossetti
Keyword(s):  
Clinical Diagnosis ◽  
Morphological Analysis ◽  
Normal Subjects ◽  
Test Time ◽  
Test Duration ◽  
Time Saving ◽  
High Agreement ◽  
Screening Programs ◽  
Screening Strategies ◽  
Suprathreshold Response

Screening programs may be useful to reduce the rate of undetected glaucoma. Compass (CMP, CenterVue, Padova, Italy) Standard Suprathreshold strategy (SST) analyses the visual function at 52 retinal locations. A new Quick Suprathreshold strategy (QST) reduces the number of tested locations to 24. With both tests, the CMP also provides an image of the central retina and a detail of the optic nerve head. The aim of this paper is to measure the performances of SST and QST compared with clinical diagnosis. 63 consecutive healthy subjects and 60 consecutive patients with perimetric defects from glaucoma in both eyes were recruited. They received one test per eye (SST or QST in randomized order); results were classified into normal, suspect and abnormal according to a global index provided in the report and called SupraThreshold Response (STR). Agreement between clinical diagnosis and test output were calculated, and test time was also measured. The agreement with the clinical diagnosis was 95.7% for SST and 95.1% for QST. When two suspect tests were excluded, agreement for QST increased to 96.7%. Test duration was 164 ± 82 s for SST and 71 ± 41 s for QST (p < 0.0001). Such a difference was similar in both glaucoma patients (respectively 231 ± 65 s vs. 105 ± 33 s, p < 0.0001) and normal subjects (98 ± 17 and 39 ± 9 s, p < 0.0001). In conclusion, SST and QST showed similar, high agreement with clinical judgement. Morphological analysis is potentially helpful in further improving the clinical usefulness of suprathreshold tests. QST is characterized by a strong time saving compared with SST.

scholarly journals An Automated Speech-in-Noise Test for Remote Testing: Development and Preliminary Evaluation

2020 ◽  
Vol 29 (3S) ◽  
pp. 564-576 ◽  
Author(s):  
Alessia Paglialonga ◽  
Edoardo Maria Polo ◽  
Marco Zanet ◽  
Giulia Rocco ◽  
Toon van Waterschoot ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Test Performance ◽  
Repeated Measures ◽  
Pearson Correlation ◽  
Test Time ◽  
Preliminary Evaluation ◽  
Test Duration ◽  
Adaptive Procedure ◽  
Speech In Noise ◽  
Noise Test

Purpose The aim of this study was to develop and evaluate a novel, automated speech-in-noise test viable for widespread in situ and remote screening. Method Vowel–consonant–vowel sounds in a multiple-choice consonant discrimination task were used. Recordings from a professional male native English speaker were used. A novel adaptive staircase procedure was developed, based on the estimated intelligibility of stimuli rather than on theoretical binomial models. Test performance was assessed in a population of 26 young adults (YAs) with normal hearing and in 72 unscreened adults (UAs), including native and nonnative English listeners. Results The proposed test provided accurate estimates of the speech recognition threshold (SRT) compared to a conventional adaptive procedure. Consistent outcomes were observed in YAs in test/retest and in controlled/uncontrolled conditions and in UAs in native and nonnative listeners. The SRT increased with increasing age, hearing loss, and self-reported hearing handicap in UAs. Test duration was similar in YAs and UAs irrespective of age and hearing loss. The test–retest repeatability of SRTs was high (Pearson correlation coefficient = .84), and the pass/fail outcomes of the test were reliable in repeated measures (Cohen's κ = .8). The test was accurate in identifying ears with pure-tone thresholds > 25 dB HL (accuracy = 0.82). Conclusion This study demonstrated the viability of the proposed test in subjects of varying language in terms of accuracy, reliability, and short test time. Further research is needed to validate the test in a larger population across a wider range of languages and hearing loss and to identify optimal classification criteria for screening purposes.

Evaluation of the Precision and Accuracy of Cycle-Average Light Duty Gasoline Vehicles Tailpipe Emission Rates Predicted by Modal Models

2020 ◽  
Vol 2674 (7) ◽  
pp. 566-584
Author(s):  
Tongchuan Wei ◽  
H. Christopher Frey
Keyword(s):  
Goodness Of Fit ◽  
Motor Vehicle ◽  
Vehicle Group ◽  
Specific Power ◽  
Emission Measurement ◽  
Emission Rates ◽  
Light Duty ◽  
Wide Range ◽  
Gasoline Vehicles ◽  
Precision And Accuracy

A vehicle specific power (VSP) modal model and the MOtor Vehicle Emission Simulator (MOVES) Operating Mode (OpMode) model have been used to evaluate and quantify the fuel use and emission rates (FUERs) for on-road vehicles. These models bin second-by-second FUERs based on factors such as VSP, speed, and others. The validity of binning approaches depends on their precision and accuracy in predicting variability in cycle-average emission rates (CAERs). The objective is to quantify the precision and accuracy of the two modeling methods. Since 2008, North Carolina State University has used portable emission measurement systems to measure tailpipe emission rates for 214 light duty gasoline vehicles on 1,677 driving cycles, including 839 outbound cycles and 838 inbound cycles on the same routes. These vehicles represent a wide range of characteristics and emission standards. For each vehicle, the models were calibrated based on outbound cycles and were validated based on inbound cycles. The goodness-of-fit of the calibrated models was assessed using linear least squares regression without intercept between model-predicted versus empirical CAERs for individual vehicles. Based on model calibration and validation, the coefficients of determination ( R2) typically range from 0.60 to 0.97 depending on the vehicle group and pollutant, indicating moderate to high precision, with precision typically higher for higher-emitting vehicle groups. The slopes of parity plots for each vehicle group and all vehicles typically range from 0.90 to 1.10, indicating good accuracy. The two modeling approaches are similar to each other at the microscopic and macroscopic levels.

The Study of Cavitation Erosion Protection Performance of Heavy-Duty Engine Coolants

2014 ◽  
Vol 651-653 ◽  
pp. 948-952
Author(s):  
Jin Mao Chen ◽  
Guan Jun Leng
Keyword(s):  
Cast Iron ◽  
Corrosion Inhibitor ◽  
Cavitation Erosion ◽  
Freezing Point ◽  
Test Time ◽  
Test Duration ◽  
Heavy Duty ◽  
Acid Type ◽  
Cylinder Liners ◽  
Erosion Protection

Ultrasonic vibratory cavitation erosion tests were carried out on studying the cavitation erosion protection performance of different type of heavy-duty engine coolants for cast iron material of wet sleeve cylinder liners. The influence of coolant type, freezing point, corrosion inhibitor content and test duration on anti-cavitation performance were analysed. The experimental results showed that the anti-cavitation erosion performance of organic acid type heavy-duty engine coolants were better than the inorganic salt type heavy-duty engine coolants. For the same formulation coolant, increasing the content of ethylene glycol or corrosion inhibitor can improve the anti-cavitation erosion performance. With the extension of ultrasonic vibration test time, the anti-cavitation erosion protection performance for cast iron was reduced.

scholarly journals Automated Smartphone Threshold Audiometry: Validity and Time Efficiency

2017 ◽  
Vol 28 (03) ◽  
pp. 200-208 ◽  
Author(s):  
Jessica van Tonder ◽  
De Wet Swanepoel ◽  
Faheema Mahomed-Asmail ◽  
Hermanus Myburgh ◽  
Robert H. Eikelboom
Keyword(s):  
Repeated Measures ◽  
Cost Effective ◽  
Test Time ◽  
Test Duration ◽  
Test Procedures ◽  
Paired Samples ◽  
Significant Difference ◽  
Effective Option ◽  
Adolescent Sample ◽  
Air Conduction

AbstractSmartphone-based threshold audiometry with automated testing has the potential to provide affordable access to audiometry in underserved contexts.To validate the threshold version (hearTest) of the validated hearScreen™ smartphone-based application using inexpensive smartphones (Android operating system) and calibrated supra-aural headphones.A repeated measures within-participant study design was employed to compare air-conduction thresholds (0.5–8 kHz) obtained through automated smartphone audiometry to thresholds obtained through conventional audiometry.A total of 95 participants were included in the study. Of these, 30 were adults, who had known bilateral hearing losses of varying degrees (mean age = 59 yr, standard deviation [SD] = 21.8; 56.7% female), and 65 were adolescents (mean age = 16.5 yr, SD = 1.2; 70.8% female), of which 61 had normal hearing and the remaining 4 had mild hearing losses.Threshold comparisons were made between the two test procedures. The Wilcoxon signed-ranked test was used for comparison of threshold correspondence between manual and smartphone thresholds and the paired samples t test was used to compare test time.Within the adult sample, 94.4% of thresholds obtained through smartphone and conventional audiometry corresponded within 10 dB or less. There was no significant difference between smartphone (6.75-min average, SD = 1.5) and conventional audiometry test duration (6.65-min average, SD = 2.5). Within the adolescent sample, 84.7% of thresholds obtained at 0.5, 2, and 4 kHz with hearTest and conventional audiometry corresponded within ≤5 dB. At 1 kHz, 79.3% of the thresholds differed by ≤10 dB. There was a significant difference (p < 0.01) between smartphone (7.09 min, SD = 1.2) and conventional audiometry test duration (3.23 min, SD = 0.6).The hearTest application with calibrated supra-aural headphones provides a cost-effective option to determine valid air-conduction hearing thresholds.

scholarly journals The analysis of the methods of hydrocarbon emission measurement according to European vehicle emission legislation

2009 ◽  
Vol 136 (1) ◽  
pp. 76-89
Author(s):  
Jerzy MERKISZ ◽  
Stanisław RADZIMIRSKI
Keyword(s):  
Measurement Methods ◽  
Vehicle Emission ◽  
Emission Measurement ◽  
Hydrocarbon Concentration ◽  
Emission Regulations ◽  
Hydrocarbon Emission ◽  
Mathematical Formulas ◽  
Total Hydrocarbons ◽  
Emission Legislation

The paper discusses the measurement methods of methane hydrocarbons, non-methane hydrocarbons and total hydrocarbons set forth in the European emission regulations pertaining to M and N vehicle types and their engines. A model for the determining of the concentration of the said hydrocarbons and mathematical formulas have been derived. The concentration of the hydrocarbons determined as per the standards and the actual hydrocarbon concentration have been compared. Based on the above, changes have been proposed in the methodology set forth in the regulations.

scholarly journals Meta-Reinforcement Learning by Tracking Task Non-stationarity

2021 ◽  
Author(s):  
Riccardo Poiani ◽  
Andrea Tirinzoni ◽  
Marcello Restelli
Keyword(s):  
Reinforcement Learning ◽  
Real World ◽  
Tracking Task ◽  
Test Time ◽  
Generation Process ◽  
Training Time ◽  
Task Uncertainty ◽  
Fast Adaptation ◽  
Novel Algorithm ◽  
Require Information

Many real-world domains are subject to a structured non-stationarity which affects the agent's goals and the environmental dynamics. Meta-reinforcement learning (RL) has been shown successful for training agents that quickly adapt to related tasks. However, most of the existing meta-RL algorithms for non-stationary domains either make strong assumptions on the task generation process or require sampling from it at training time. In this paper, we propose a novel algorithm (TRIO) that optimizes for the future by explicitly tracking the task evolution through time. At training time, TRIO learns a variational module to quickly identify latent parameters from experience samples. This module is learned jointly with an optimal exploration policy that takes task uncertainty into account. At test time, TRIO tracks the evolution of the latent parameters online, hence reducing the uncertainty over future tasks and obtaining fast adaptation through the meta-learned policy. Unlike most existing methods, TRIO does not assume Markovian task-evolution processes, it does not require information about the non-stationarity at training time, and it captures complex changes undergoing in the environment. We evaluate our algorithm on different simulated problems and show it outperforms competitive baselines.

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