scholarly journals Particle Emissions and Disc Temperature Profiles from a Commercial Brake System Tested on a Dynamometer under Real-World Cycles

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 377
Author(s):  
Athanasios Mamakos ◽  
Katharina Kolbeck ◽  
Michael Arndt ◽  
Thomas Schröder ◽  
Matthias Bernhard
Keyword(s):  
Los Angeles ◽  
Real World ◽  
Test Procedure ◽  
Brake System ◽  
Short Version ◽  
Emission Rates ◽  
Particle Emissions ◽  
Radial Temperature ◽  
Potential Formation ◽  
Brake Dynamometer

The particle emissions from a commercial brake system utilizing copper-free pads have been characterized on a brake dynamometer under two real-world driving cycles. These included a novel cycle developed from analysis of the database of the World Harmonized Test Procedure (WLTP-Brake) and a short version of the Los Angeles City Traffic cycle (3h-LACT) developed in the framework of the European LowBraSys project. Disc temperature measurements using an array of embedded thermocouples revealed a large temporal and spatial non-uniformity with the radial temperature distribution depending also on the test procedure. Averaging over the duration of the cycle, it effectively reduced the influence of thermocouple positioning, allowing for more reliable quantification of the effectiveness of convective cooling. Particulate Matter (PM) emissions were similar for both cycles with PM2.5 averaging at 2.2 (±0.2) mg/km over the WLTP-Brake and 2.2 (±0.2) mg/km over the 3h-LACT, respectively. The corresponding PM10 emissions were 5.6 (±0.2) mg/km and 8.6 (±0.7) mg/km, respectively. The measurements revealed the formation of nanosized particles peaking at 10 nm, which were thermally stable at 350 °C under both cycles. Volatile nanoparticles were observed over the more demanding 3h-LACT cycle, with their emission rates decreasing with increasing the tunnel flow, suggesting nucleation of organic vapors released during braking as a potential formation process.

scholarly journals Impacts on Brake Particle Emission Testing

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1132 ◽  
Author(s):  
Sebastian Gramstat ◽  
Thilo Mertens ◽  
Robert Waninger ◽  
Dmytro Lugovyy
Keyword(s):  
Test Procedure ◽  
Particle Emission ◽  
Vehicle Speed ◽  
Particle Emissions ◽  
Emission Testing ◽  
Relevant Role ◽  
Brake Dynamometer ◽  
Brake Lining ◽  
The Impact

The presented article picks out brake particle emission testing as a central theme. Those emissions are part of the so-called non-exhaust emissions, which play an increasing role for particle emissions from transportation. The authors propose a laboratory test setup by using a brake dynamometer and a constant volume sampling approach to determine the emissions in regard to the particle number concentration. Several impacts were investigated while the same test cycle (novel worldwide harmonized light vehicles test procedure (novel-WLTP)) was applied. In a first item, the importance of the bedding process was investigated and it is shown that friction couples without bedding emit much more particles. Furthermore, the efforts for reaching a bedded friction state are discussed. Additionally, the impact of brake lining compositions is investigated and shows that NAO concepts own crucial advantages in terms of brake particle emissions. Another impact, the vehicle weight and inertia, respectively, shows how important lightweight measures and brake cooling improvements are. Finally, the role of the load profile is discussed, which shows the importance of driving parameters like vehicle speed and reservoir dynamics. The authors show that, under urban driving conditions, extreme low particle emissions are detected. Furthermore, it is explained that off-brake emissions can play a relevant role in regard to brake particle emissions.

scholarly journals Could aerosol emissions be used for regional heat wave mitigation?

2012 ◽  
Vol 12 (9) ◽  
pp. 23793-23828
Author(s):  
D. N. Bernstein ◽  
J. D. Neelin ◽  
Q. B. Li ◽  
D. Chen
Keyword(s):  
Los Angeles ◽  
Heat Wave ◽  
Heat Waves ◽  
Regional Scale ◽  
Middle Part ◽  
Emission Rates ◽  
Sulfate Aerosols ◽  
Geographical Differences ◽  
Aerosol Emission ◽  
Trade Offs

Abstract. Geoengineering applications by injection of sulfate aerosols into the stratosphere are under consideration as a measure of last resort to counter global warming. Here adaptation to a potential regional scale application to offset the impacts of heat waves is critically examined. The effect of regional scale sulfate aerosol emission over California in each of two days of the July 2006 heat wave using the Weather Research and Forecasting model with fully coupled chemistry (WRF-Chem) is used to quantify potential reductions in surface temperature as a function of emission rates in the lower stratosphere. Over the range considered, afternoon temperature reductions scale almost linearly with injections. Local meteorological factors yield geographical differences in surface air temperature sensitivity. For emission rates of approximately 30 μg m−2 s−1 of sulfate aerosols (with standard WRF-Chem size distribution) over the region, temperature decreases of around 7 °C result during the middle part of the day over the Central Valley, one of the hardest hit by the heat wave. Regions more ventilated with oceanic air such as Los Angeles have slightly smaller reductions. The length of the hottest part of the day is also reduced. Advection effects on the aerosol cloud must be more carefully forecast for smaller injection regions. Verification of the impacts could be done via measurements of differences in reflected and surface downward shortwave. Such regional geoengineering applications with specific near-term target effects but smaller cost and side effects could potentially provide a means of testing larger scale applications. However, design trade-offs differ from global applications and the size of the required injections and the necessity of injection close to the target region raise substantial concerns. The evaluation of this regional scale application is thus consistent with global model evaluations emphasizing that mitigation via reduction of fossil fuels remains preferable to considering geoengineering with sulfate aerosols.

scholarly journals Real world experience with coronary sinus reducer implantation for the treatment of refractory angina: a single-centre experience

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
J P Dias Ferreira Reis ◽  
R Ramos ◽  
P Rio ◽  
A Fiarresga ◽  
D Cacela ◽  
...  
Keyword(s):  
Coronary Sinus ◽  
Real World ◽  
Therapeutic Option ◽  
Objective Evaluation ◽  
Short Version ◽  
Refractory Angina ◽  
Single Centre ◽  
Real World Data ◽  
Serious Adverse Events

Abstract Background Coronary sinus Reducer device (CSF) implantation is a novel therapeutic option to relieve symptoms in patients with refractory angina (RA). There is limited real-world data describing its use outside of clinical trials. Aim To assess the safety and efficacy of this procedure in a real-world setting. Methods This is a report of a single centre prospective registry of consecutive patients with RA (CCS II-IV) deemed unsuitable for revascularization. Between May 2017 and August 2019, 17 patients were referred to CSF implantation. Baseline and follow-up evaluation consisted of clinical assessment, including completion of the short version of the Seattle Angina Questionnaire (SAQ-7) and CCS class evaluation and objective evaluation by transthoracic echocardiography and cardiopulmonary exercise test (CPET). Results A total of 13 patients (70,6±6,5 years, 76,9% male) underwent CSF implantation with a procedural success of 84.6%. No cases of periprocedural serious adverse events were reported. At 12-month follow-up, any reduction in CCS Class was achieved in 72.7% of cases, with 27.2% reducing 2 CCS classes. Baseline CCS score was reduced from 2.8±0.4 to 1.7±0.8 (p=0.009). Quality of life (QoL) was significantly improved as assessed by the improvement seen in all items of SAQ-7 (p<0.017 for all). CPET duration was significantly increased (p=0.034), but no change was noted in the remainder CPET variables. During follow-up, 3 patients suffered myocardial infarction, resulting in 1 death. Conclusion CSF implantation in patients with RA was safe and led to a significant reduction of the angina burden and improvement of QoL at 12-month follow-up. FUNDunding Acknowledgement Type of funding sources: None.

Real-World Emissions from a Modern Production Vehicle Driven in Los Angeles

Air & Waste ◽  
1993 ◽  
Vol 43 (10) ◽  
pp. 1351-1357 ◽  
Author(s):  
Nelson A. Kelly ◽  
Peter J. Groblicki
Keyword(s):  
Los Angeles ◽  
Real World

Analysis of wear induced particle emissions from brake pads during the worldwide harmonized light vehicles test procedure (WLTP)

Wear ◽  
2021 ◽  
Vol 466-467 ◽  
pp. 203539
Author(s):  
Jongsung Park ◽  
Byungsoo Joo ◽  
Hyungjo Seo ◽  
Wansu Song ◽  
Jung Ju Lee ◽  
...  
Keyword(s):  
Test Procedure ◽  
Particle Emissions ◽  
Brake Pads

Measurement and Evaluation of Real-World Speed and Acceleration Activity Envelopes for Light-Duty Vehicles

2015 ◽  
Vol 2503 (1) ◽  
pp. 128-136 ◽  
Author(s):  
Bin Liu ◽  
H. Christopher Frey
Keyword(s):  
Real World ◽  
Test Procedure ◽  
Accurate Estimation ◽  
Vehicle Type ◽  
Light Duty ◽  
Road Grade ◽  
Light Duty Vehicle ◽  
Curb Weight ◽  
Vehicle Activity ◽  
Light Duty Vehicles

Accurate estimation of vehicle activity is critically important for the accurate estimation of emissions. To provide a benchmark for estimation of vehicle speed trajectories such as those from traffic simulation models, this paper demonstrates a method for quantifying light-duty vehicle activity envelopes based on real-world activity data for 100 light-duty vehicles, including conventional passenger cars, passenger trucks, and hybrid electric vehicles. The vehicle activity envelope was quanti-fied in the 95% frequency range of acceleration for each of 15 speed bins with intervals of 5 mph and a speed bin for greater than 75 mph. Potential factors affecting the activity envelope were evaluated; these factors included vehicle type, transmission type, road grade, engine displacement, engine horsepower, curb weight, and ratio of horsepower to curb weight. The activity envelope was wider for speeds ranging from 5 to 20 mph and narrowed as speed increased. The latter was consistent with a constraint on maximum achievable engine power demand. The envelope was weakly sensitive to factors such as type of vehicle, type of transmission, road grade, and engine horsepower. The effect of road grade on cycle average emissions rates was evaluated for selected real-word cycles. The measured activity envelope was compared with those of dynamometer driving cycles, such as the federal test procedure, highway fuel economy test, SC03, and US06 cycles. The effect of intervehicle variability on the activity envelope was minor; this factor implied that the envelope could be quantified based on a smaller vehicle sample than used for this study.

scholarly journals Variability in Measured Real-World Operational Energy Use and Emission Rates of a Plug-In Hybrid Electric Vehicle

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1140 ◽  
Author(s):  
H. Christopher Frey ◽  
Xiaohui Zheng ◽  
Jiangchuan Hu
Keyword(s):  
Real World ◽  
Hybrid Electric Vehicle ◽  
Energy Use ◽  
Average Energy ◽  
Specific Power ◽  
Emission Measurement ◽  
Emission Rates ◽  
Wide Range ◽  
Hybrid Electric ◽  
Cold Starts

Compared to comparably sized conventional light duty gasoline vehicles (CLDGVs), plug-in hybrid electric vehicles (PHEVs) may offer benefits of improved energy economy, reduced emissions, and the flexibility to use electricity as an energy source. PHEVs operate in either charge depleting (CD) or charge sustaining (CS) mode; the engine has the ability to turn on and off; and the engine can have multiple cold starts. A method is demonstrated for quantifying the real-world activity, energy use, and emissions of PHEVs, taking into account these operational characteristics and differences in electricity generation resource mix. A 2013 Toyota Prius plug-in was measured using a portable emission measurement system. Vehicle specific power (VSP) based modal average energy use and emission rates are inferred to assess trends in energy use and emissions with respect to engine load and for comparisons of engine on versus engine off, and cold start versus hot stabilized running. The results show that, compared to CLDGVs, the PHEV operating in CD mode has improved energy efficiency and lower CO2, CO, HC, NOx, and PM2.5 emission rates for a wide range of power generation fuel mixes. However, PHEV energy use and emission rates are highly variable, with periods of relatively high on-road emission rates related to cold starts.

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