Methodology for instantaneous average exhaust gas mass flow rate measurement

Fonseca, Natalia; Kindelán, Jesús Casanova; Martí, J.; ñez,

doi:10.1016/j.flowmeasinst.2016.04.007

Cited by 19 publications

(4 citation statements)

References 22 publications

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“…Square root errors, acoustic effects and aliasing are wellunderstood, e.g., Nakamura et al (2005) and González et al (2016) have resolved these errors when using Pitot tubes to measure flow rate at the exhaust tailpipe.…”

Section: Background Motivation and Existing Literaturementioning

confidence: 99%

Measurement and Prediction of Discharge Coefficients in Highly Compressible Pulsating Flows to Improve EGR Flow Estimation and Modeling of Engine Flows

Brahma

2019

Front. Mech. Eng.

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An assumption of constant discharge coefficient (C d) is often made when modeling highly compressible pulsating engine flows through valves or other restrictions. Similarly, orifices and flow-nozzles used for real-time EGR flow estimation are often calibrated at a few steady-state points with one single constant C d that minimizes the error over the selected points. This quasi-steady assumption is based on asymptotically constant C d observed at high Reynolds number for steady (non-pulsating) flow. It has been shown in this work that this assumption is not accurate for pulsating flow, particularly at large amplitudes and low flow rates. The discharge coefficient of a square-edged orifice placed in the exhaust stream of a diesel engine produced C d 's varying between 0.60 and 0.90 for critical/near-critical flows. A novel pulsating flow measurement apparatus that allowed independent variation of pressure, flow rate and frequency and allowed reproducible measurements independent of transducer characteristics, produced C d 's in the range of 0.25-0.60 with a similar square-edge orifice. The variation in C d was found to be correlated to two dimensionless variables, η and ξ , defined as the standard deviation of the pulsating pressure signal, σ p , normalized by ρV 2 and p across the orifice, respectively. The results suggest that many aspects of compressible pulsating flow through flow restrictions are yet to be understood.

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Section: Background Motivation and Existing Literaturementioning

confidence: 99%

Measurement and Prediction of Discharge Coefficients in Highly Compressible Pulsating Flows to Improve EGR Flow Estimation and Modeling of Engine Flows

Brahma

2019

Front. Mech. Eng.

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“…As described by Gonzales et al [33], there is a high frequency component to the pressure waves of the exhaust gas, therefore the exhaust gas flow is not steady or constant. However, for the purpose of the present work, where the measurement of the gas speed has been performed with a sampling rate of 2 samples/s, we can consider the flow as quasi-static.…”

Section: Validation Of Gas Speed Measured By Pitot Tubementioning

confidence: 99%

Available Energy in Cars’ Exhaust System for IoT Remote Exhaust Gas Sensor and Piezoelectric Harvesting

et al. 2020

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The exhaust system of the light-duty diesel engine has been evaluated as a potential environment for a mechanical energy recovery system for powering an IoT (Internet of Things) remote sensor. Temperature, pressure, gas speed, mass flow rate have been measured in order to characterize the exhaust gas. At any engine point explored, thermal energy is by far the most dominant portion of the exhaust energy, followed by the pressure energy and lastly kinetic energy is the smallest fraction of the exhaust energy. A piezoelectric flexible device has been tested as a possible candidate as an energy harvester converting the kinetic energy of the exhaust gas flow, with a promising amount of electrical energy generated in the order of microjoules for an urban or extra-urban circuit.

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“…Further, this system was used in the study of high instantaneous NOₓ emissions by (Mera et al, 2019b), with a sampling frequency of 10 Hz for the measured parameters. The PEMS consists of a pitot-type exhaust flow meter (EFM) (Fonseca González et al, 2016), a direct-installation Horiba Mexa 720 ceramic zirconium NOₓ sensor, a relative air-fuel ratio (λ) meter, exhaust gas temperature sensors, a global positioning system (GPS), and a weather station to record ambient temperature and humidity. The NOₓ sensor measured concentration directly in the exhaust line at the EFM level, with an accuracy of ±30 ppm NOₓ (0−1000 ppm), ±3 % (1001−2000 ppm), and ±5 % (2001−3000 ppm).…”

Section: Methodsmentioning

confidence: 99%

NOₓ emissions from passenger cars under real driving conditions

Rosero¹

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̶ iv ̶ metrics, such as R 2 and RMSE. The use of vehicle activity parameters becomes useful inputs to model physics-based, and machine learning models. A hybrid approach that combines the physics-based model with a machine learning model for the aftertreatment system is a good alternative as enables the use of the advantages of the physics and datadriven models for reducing the amount of dimensioning and characterisation of the aftertreatment layout.

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Methodology for instantaneous average exhaust gas mass flow rate measurement

Cited by 19 publications

References 22 publications

Measurement and Prediction of Discharge Coefficients in Highly Compressible Pulsating Flows to Improve EGR Flow Estimation and Modeling of Engine Flows

Measurement and Prediction of Discharge Coefficients in Highly Compressible Pulsating Flows to Improve EGR Flow Estimation and Modeling of Engine Flows

Available Energy in Cars’ Exhaust System for IoT Remote Exhaust Gas Sensor and Piezoelectric Harvesting

NOₓ emissions from passenger cars under real driving conditions

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