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How well can mPEMS measure gas phase motor vehicle exhaust emissions?

Ford Motor Company-Diep Vu, Joseph Szente, Michael Loos, Matti Maricq
  • Technical Paper
  • 2020-01-0369
To be published on 2020-04-14 by SAE International in United States
“Real world emissions” is an emerging area of focus in motor vehicle related air quality. These emissions are commonly recorded using portable emissions measurement systems (PEMS) designed for regulatory application, which are large, complex and costly. Miniature PEMS (mPEMS) is a developing technology that can significantly simplify on-board emissions measurement and potentially promote widespread use. Whereas full PEMS use analyzers to record NOx, CO, and HCs similar to those in emissions laboratories, mPEMS tend to use electrochemical sensors and compact spectroscopic detectors for their small size and low cost. The present work evaluates this approach by comparing measurements of NOx, CO, CO2 and HC emissions from five commercial mPEMS to both laboratory and full regulatory PEMS measurements. It further examines the use of vehicle on-board diagnostics data to calculate exhaust flow, as an alternative to on-vehicle exhaust flow measurement. The evaluations include two vehicle types, gasoline direct injection and diesel, and employ the US EPA and Worldwide Harmonized Light duty drive cycles. The results show that two classes of electrochemical NOx sensors are capable of…
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The Prospect and Benefits of Using the Partial-Averaged Navier-Stokes Method for Engine Flows

AVL LIST GmbH-Branislav Basara, Zoran Pavlovic
Texas A&M University-Sharath Girimaji
  • Technical Paper
  • 2020-01-1107
To be published on 2020-04-14 by SAE International in United States
This paper presents calculations of engine flows by using the Partially-Averaged Navier-Stokes (PANS) method [1]. The PANS is a scale-resolving turbulence computational approach designed to resolve large scale fluctuations and model the remainder with appropriate closures. Depending upon the prescribed cut-off length (filter width) the method adjusts seamlessly from the Reynolds-Averaged Navier-Stokes (RANS) to the Direct Numerical Solution (DNS) of the Navier-Stokes equations. In the conventional well-established PANS, the unresolved to total kinetic energy ratio fk known as the cut-off control parameter, is calculated from the grid spacing and the computed integral turbulence length scale. Several formulations have been derived up to now. In most of these formulations, fk is obtained by summing up the resolved turbulence, while the unresolved motion is computed from the modelled equation. The PANS method was successfully used on large number applications but mainly on static geometries, e.g. [2]; [3]. This is due to calculations of the resolved kinetic energy which is obtained by suitably averaging of the resolved field. Such averaging process is expensive and impractical for engines as…
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RDE-Compliant PEMS Testing of a Gasoline Euro 6d-TEMP Passenger Car at Two Ambient Temperatures with a Focus on the Cold Start Effect

BOSMAL / Poznan University of Technology-Jerzy Merkisz
BOSMAL Automotive R&D Institute, Ltd.-Piotr Bielaczyc, Joseph Woodburn
  • Technical Paper
  • 2020-01-0379
To be published on 2020-04-14 by SAE International in United States
European Union RDE (real driving emissions) legislation requires that new vehicles be subjected to emissions tests on public roads. Performing emissions testing outside a laboratory setting immediately raises the question of the impact of ambient conditions - especially temperature - on the results. In the spirit of RDE legislation, a wide range of ambient temperatures are permissible, with mathematical moderation (correction) of the results only permissible for ambient temperatures <0°C and >+30°C. Within the standard range of temperatures (0°C to +30°C), no correction for temperature is applied to emissions results and the applicable emissions limits have to be met. Given the well-known link between the thermal state of an engine and its emissions following cold start, ambient temperature can be of great importance in determining whether a vehicle meets emissions requirements during an RDE test. This paper reports the results of full RDE-compliant on-road emissions tests performed on a Euro 6d-TEMP passenger car with a direct injection spark ignition engine and a gasoline particle filter. Testing was performed at two temperatures, both lying within the…
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Real-world Emission Analysis Methods Using Sensor-based Emission Measurement System

Ibaraki University-Kotaro Tanaka
NGK Spark Plug Co., Ltd.-Takeshi Tange
  • Technical Paper
  • 2020-01-0381
To be published on 2020-04-14 by SAE International in United States
Every year, due to exhaust gas regulations that are getting stricter, the average air pollution is going to be solved, but the local roadside pollution is still pressing issue. In order to solve this local roadside pollution problem, it is necessary to evaluate and/or predict “where” and “how much” pollutants such as NOx are emitted. In recent years, Real Driving Emission regulations using PEMS (Portable Emission Measurement System) have been introduced mainly in Europe. However, PEMS has a configuration close to 100 kg, and its weight affects the driving conditions of vehicles running on actual roads. In this study, we focused on the analysis of real world emissions using SEMS (Sensor-based / Simple Emission Measurement System). Whereas PEMS is a method of sampling and analyzing exhaust gas, SEMS directly attaches NOx sensor and PM sensor to the exhaust pipe and measures the concentration. Although SEMS has a limited number of items that can be measured compared to PEMS, other analyzes are possible by devising the analysis method. This paper focuses on the analysis method of…
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Review of Vehicle Engine Efficiency and Emissions

Corning, Inc.-Ameya Joshi
  • Technical Paper
  • 2020-01-0352
To be published on 2020-04-14 by SAE International in United States
This review paper covers major regulatory and technology developments in 2019 pertinent to tailpipe emissions of greenhouse gases and criteria pollutants. Europe has proposed ambitious reductions in CO2 limits for both light- and heavy-duty sectors. The challenge is compounded with changing measurement norms and a significant shift away from fuel efficient diesels in the light-duty (LD) space. Both incremental and step changes are being made to advance internal combustion. New studies show that in-use NOx emissions from diesels can be much lower than required by the Euro 6 regulation. Discussions have already started on Euro 7 regulations, and the leading regulatory concepts and proposed technical solutions are provided. In the heavy-duty (HD) sector, the progress is outlined in improving engine and vehicle fuel efficiency through the US Department of Energy’s (DOE’s) SuperTruck II program and other representative studies. Common approaches among the participants include hybridization, waste heat recovery, and both open- and closed cycle incremental improvements. Emissions control focus is on evaluating pathways to achieve California’s contemplated low-NOx standards, recently also supported by the US…
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How well can mPEMS measure particulate matter motor vehicle exhaust emissions?

Ford Motor Company-Diep Vu, Joseph Szente, Michael Loos, Matti Maricq
  • Technical Paper
  • 2020-01-0391
To be published on 2020-04-14 by SAE International in United States
Real world emissions are increasingly the standard of comparison for motor vehicle exhaust impact on the environment. The ability to collect such data has thus far relied primarily on full portable emissions measurement systems (PEMS) that are bulky, expensive, and time consuming to set up. The present work examines four compact, low cost, miniature PEMS that offer the potential to expand our ability to record real world exhaust emissions over a larger number of operating conditions and combustion engine applications than currently possible. It specifically addresses the particulate matter (PM) capabilities of these mPEMS, which employ three different methodologies for particle measurement, diffusion charger, optical scattering, and a multiplex process that combines scattering, opacity, and ionization. Their performance is evaluated against solid particle number and PM mass with both vehicle tests and flame generated soot. These mPEMS detect PM emissions at <1 mg/m3 and 10^6 particles/cm3, levels that are consistent with modern vehicles meeting ~1 mg/mi and 6 x10^11 particles/km emissions standards. Difficulties remain in quantifying the emissions in terms of number or mass. The…
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Impact of Post-Injection Parameters on Soot and Hydrocarbon Emissions in a Common-Rail Heavy-Duty Diesel Engine

Wang Pan, Yan Wu, Yi Jing, Huang Zizeng
  • Technical Paper
  • 2020-01-0374
To be published on 2020-04-14 by SAE International in United States
In this paper, based on a direct injection (DI) diesel engine, soot and exhaust gaseous emissions were measured by a smoke meter and multi-component gas analyzer based on Fourier Transform Infrared (FTIR) spectroscopy under post-injection condition. The post-injection timing changed from 20 crank angle degree (CAD) after top dead center (ATDC) to 120 CAD ATDC, and the post-injection mass was set to either 5mg, 10mg or 15mg, to find a suitable post-injection strategy in a wide assessment range based on diesel oxidation catalyst (DOC) coupled diesel particle filter (DPF) after-treatment technology demands, considering emission reduction and after-treatment gas atmosphere investigation. The results showed that post-injection could achieve NOx emission reduction, up to 14%. Besides, post-injection led to worsening soot emissions, and more hydrocarbon (HC) emissions were detected compared to the condition without the post-injection. With the post-injection, a higher concentration of unsaturated HC emissions (such as C2H2, C2H4, and C3H6), formaldehyde (HCHO), and acetaldehyde (CH3CHO) appeared at late post-injection (after 70°CA). In the measured species, at 80°CA post-injection timing and with 10mg post-injection mass, species…
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Improving Heavy Duty Natural Gas Engine Efficiency: A Systematic Approach to Application of Dedicated EGR

Southwest Research Institute-Michael C. Kocsis, Robert Mitchell, Ahmed Abdul Moiz, Vickey Kalaskar, D. Ryan Williams, Scott Sjovall
  • Technical Paper
  • 2020-01-0818
To be published on 2020-04-14 by SAE International in United States
The worldwide trend of tightening CO2 emissions standards and desire for near zero emissions is driving development of high efficiency natural gas engines for a low CO2 replacement of traditional diesel engines. A Cummins Westport ISX12 G was previously converted to a Dedicated EGR® (D-EGR®) configuration with two out of the six cylinders acting as the EGR producing cylinders. Using a systems approach, the combustion and turbocharging systems were optimized for improved efficiency while maintaining the potential for achieving 0.02 g/bhp-hr NOX standards. A prototype variable nozzle turbocharger was selected to maintain the stock torque curve. The EGR delivery method enabled a reduction in pre-turbine pressure as the turbine was not required to be undersized to drive EGR. A high energy Dual Coil Offset (DCO®) ignition system was utilized to maintain stable combustion with increased EGR rates. High compression ratio, reduced squish pistons were designed to maintain MBT combustion phasing and fast burn rates along the torque curve. The final engine configuration was tested on the Heavy-Duty Supplemental Emissions Test (SET), a 13-mode steady-state engine…
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Development of a Sectional Soot Model Based Methodology for the Prediction of Soot Engine-Out Emissions in GDI Units

Istituto Motori - CNR-Silvana Di Iorio
Istituto Motori CNR-Adrian Irimescu
  • Technical Paper
  • 2020-01-0239
To be published on 2020-04-14 by SAE International in United States
With the aim of identifying technical solutions to lower the particulate matter emissions, the engine research community made a consistent effort to investigate the root causes leading to soot formation. Nowadays, the computational power increase allows the use of advanced soot emissions models in 3D-CFD turbulent reacting flows simulations. However, the adaptation of soot models originally developed for Diesel applications to gasoline direct injection engines is still an ongoing process. A limited number of studies in literature attempted to model soot produced by gasoline direct injection engines, obtaining a qualitative agreement with the experiments. To the authors’ best knowledge, none of the previous studies provided a methodology to quantitatively match particulate matter, particulate number and particle size distribution function measured at the exhaust without a case-by-case soot model tuning. In the present study, a Sectional Method-based methodology to quantitatively predict gasoline direct injection soot formation is presented and validated against engine-out emissions measured on a single-cylinder optically accessible gasoline direct injection research engine. While adapting the model to the gasoline direct injection soot framework, attention…
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A Novel Technique for Measuring Cycle-Resolved Cold Start Emissions Applied to a Gasoline Turbocharged Direct Injection Engine

Ford Motor Company-Peter Moilanen, Steven Wooldridge, Jianwen Yi
University of Texas-Jinghu Hu, Matthew Hall, Ron Matthews
  • Technical Paper
  • 2020-01-0312
To be published on 2020-04-14 by SAE International in United States
There is keen interest in understanding the origins of engine-out unburned hydrocarbons emitted during SI engine cold start. This is especially true for the first few firing cycles, which can contribute disproportionately to the total emissions measured over standard drive cycles such as the US Federal Test Procedure (FTP). This study reports on the development of a novel methodology for capturing and quantifying unburned hydrocarbon emissions (HC), CO, and CO2 on a cycle-by-cycle basis during an engine cold start. The method was demonstrated by applying it to a 4 cylinder 2 liter GTDI (Gasoline Turbocharged Direct Injection) engine for cold start conditions at an ambient temperature of 22°C. For this technique, the entirety of the engine exhaust gas was captured for a predetermined number of firing cycles. By capturing the exhaust of different numbers of firing cycles, from one to five for example, the emissions contribution of each successive cycle was determined on an ensemble average basis. The development of custom engine control software allowed predetermined event-by event control of individual cylinder fuel injection and…