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| 2. |
- Alemani, Mattia, et al.
(författare)
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Scaling effects of measuring disc brake airborne particulate matter emissions – A comparison of a pin-on-disc tribometer and an inertia dynamometer bench under dragging conditions
- 2018
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Ingår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology. - : Sage Publications. - 1350-6501 .- 2041-305X. ; 232:12, s. 1538-1547
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Tidskriftsartikel (refereegranskat)abstract
- An important contributor to non-exhaust emissions in urban areas is airborne particulate matter originating from brake systems. A well-established way to test such systems in industry is to use inertia dynamometer benches; although they are quite expensive to run. Pin-on-disc tribometers, on the other hand, are relatively cheap to run, but simplify the real system. The literature indicates promising correlations between these two test stands with regard to measured airborne number distribution. Recent studies also show a strong dependency between the airborne number concentration and the disc temperature. However, a direct comparison that also takes into account temperature effects is missing. The aim of this paper is, therefore, to investigate how the transition temperature is affected by the different test scales, under dragging conditions, and the effects on total concentration and size distribution. New and used low-steel pins/pads were tested against cast iron discs/rotors on both the aforementioned test stands, appositely designed for particulate emission studies. A constant normal load and constant rotational velocity were imposed in both test stands. Results show that a transition temperature can always be identified. However, it is influenced by the test scale and the frictional pair status. Nevertheless, emissions are assessed similarly when an equivalent frictional pair status is analysed (e.g. run-in). Further investigations for fully run-in samples on the pin-on-disc should be performed in order to finally assess the possibility of using the tribometers for the initial assessment of different friction materials.
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| 3. |
- Matejka, Vlastimil, et al.
(författare)
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Airborne Wear Particle Emissions Produced during the Dyno Bench Tests with a Slag Containing Semi-Metallic Brake Pads
- 2020
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Ingår i: Atmosphere. - : MDPI. - 2073-4433. ; 11:11
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present paper is to investigate the level of airborne wear particles released during the dyno-bench tests with the brake pads consisting of alkali-activated slag as an abrasive. Airborne wear particles are generated with a full-scale dyno-bench adapted for airborne wear particles emission studies. The tested disc brake is equipped with two semi-metallic brake pads and a grey cast iron brake disc. A reduced Los Angeles City Traffic (LACT) driving cycle, developed within the LOWBRASYS project (European Union's Horizon 2020 research and innovation programme), is used to mimic city driving. The same friction pair is used six times with reduced LACT cycle. The weight loss and thickness of the pads and disc are registered after each test cycle ends. The amount of the airborne wear particles emissions released during each test cycle are characterized using a PM10 impactor and electric low-pressure impactor. The obtained data of wear particle emissions are correlated with the parameters of the brake stops. The maximum disc temperature was indicated as the parameter having the largest influence on the production of particle emissions together with the duration of the brake event
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| 4. |
- Matějka, Vlastimil, et al.
(författare)
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Dependency of PM10 particle emission on stability of friction coefficient and character of friction surface
- 2016
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Konferensbidrag (refereegranskat)abstract
- Two pairs of low-metallic brake pads (BP1 and BP2) with different chemical composition as measured using wave dispersive X-ray fluorescence spectroscopy were selected for this study. The brake pads were tested with inertia brake dynamometer adapted for isokinetic sampling of PM10 wear particles. Modified SAE J2707 (part B) testing procedure was used for both test. PM10 particles released during the brake stops were captured under isokinetic conditions on 47mm quartz filter, the particles bigger than 10 micron were removed by PM10 cyclone. The character of the friction surface of brake pads was studied using scanning electron microscopy. It was observed that COF of sample BP1 grows during the individual brake events from approx. 0.4 to 0.7; while the COF obtained for BP2 shows stable value approx. 0.4 during individual brake stops. The average PM10 concentration in given experimental set-up reached value 1.47 and 0.56 mg/m3 for sample BP1 and BP2, respectively.
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| 5. |
- Metinoz, Ibrahim, et al.
(författare)
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COULD PIN-ON-DISC TRIBOMETERS BE USED TO STUDY THE FRICTION/WEAR PERFORMANCE OF DISC BRAKE MATERIALS?
- 2016
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Ingår i: EUROBRAKE 2016. - Milan.
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Konferensbidrag (refereegranskat)abstract
- Pin-on-disc tribometers are used by the academia to study friction and wear of disc brake materials. It has been debated if a simplified set-up could reproduce the friction and wear behaviour of the disc brake assembly. The aim of this paper is to investigate and discuss this topic by comparing the friction surfaces with diverse microscopy techniques. Also, coefficients of friction, wear, and collected airborne wear particles are compared. Although the tests are based on different testing procedures (tribometers - drag test and dyno-bench test – single station), the results show that tribometers provide information related to the friction-wear performance, character of friction surfaces, and character of wear particles, which mirror the behaviour of the samples during dyno-bench tests.
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| 6. |
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| 7. |
- Perricone, Guido, 1973-, et al.
(författare)
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A concept for reducing PM10 emissions for car brakes by 50%
- 2018
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Ingår i: Wear. - : Elsevier. - 0043-1648 .- 1873-2577. ; 396, s. 135-145
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Tidskriftsartikel (refereegranskat)abstract
- With regard to airborne particles with an aerodynamic diameter of less than 10 mu m (PM10), in countries in the European Union, the mass of brake emissions equals approximately 8-27% of the total traffic-related emissions. Using a research methodology combining tests at different scale levels with contact mechanics simulations and PM10 chemical characterization, the REBRAKE EU-financed project had the following aims: i) to demonstrate the possibility of reducing the PM10 fraction of the airborne particulate from brake wear by 50 wt%; ii) to enhance the general understanding on the physical and chemical phenomena underlying the brake wear process. The results achieved so far indicate that it is possible to design a disc brake system for a European standard car affording at least a 32 wt% PM10 emission reduction using a standard European pad and a heat-treated rotor. A further reduction to 65 wt% PM10 emission could be achieved with NAO pad material and the same heat-treated disc.
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| 8. |
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| 9. |
- Perricone, Guido, et al.
(författare)
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A proposed driving cycle for brake emissions investigation for test stand
- 2020
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Ingår i: Proceedings of the Institution of mechanical engineers. Part D, journal of automobile engineering. - : Sage Publications. - 0954-4070 .- 2041-2991. ; 234:1, s. 122-135
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Tidskriftsartikel (refereegranskat)abstract
- Particulate matter emission factors from vehicle brakes are difficult to assess directly from the field. Moreover, there is a lack of a standardized cycle and test stand for evaluating brake emissions. For these reasons, a test cycle was developed from real driving data collected from a car. This new test cycle was implemented on an inertia disc brake dynamometer appositely designed for brake particle emission studies. Results reveal that, for the brake system used as an example, the obtained emission factors for the urban driving conditions studied are comparable to EURO 6 regulations in terms of particle number and comparable to EURO 4 levels in terms of mass with brake emission factors equal to 4.37-6.46 x 10(11) particles/km and 44-48 mg/km, respectively.
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| 10. |
- Perricone, Guido, 1973-, et al.
(författare)
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A proposed dyno bench test cycle to study particle emissions from disc brakes
- 2014
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Konferensbidrag (refereegranskat)abstract
- In urban areas, the impact of on-road vehicles on particulate matter is well acknowledged. Particulates originating from vehicles come not only from the engine exhaust emissions, but also from wear processes in brakes and between tires and road surface. In the EU, these non-exhaust vehicle emissions equal approximately 50 % of the exhaust emissions of PM10 (particles with aerodynamic diameters smaller than 10 μm).To reduce the air pollution, tail pipe emissions are today regulated. Detailed test protocols for engine exhaust verification and certification, using different driving cycles, are available. However, there are no formal test protocols for particulate emissions from disc brakes.Here a test cycle for disc brakes is proposed considering a typical European car usage. It consists of nine different braking blocks, starting from a burning-in and involving town, country road, highway and hill descend conditions.To evaluate the test cycle, a front brake assembly was set-up in a shaft-type inertia dynamometer. Particle emissions were continuously registered using a particle counter, which can measure particulate matter from ultrafine to coarse sizeThe conclusion is that the proposed test cycle can be used to evaluate particulate emissions from disc brakes, and the next step towards a test protocol should be to improve the measurements using a clean environment around the brake assembly and isokinetic sampling.
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