Brake wear

The braking torque of the shoe brakes may diminish with the number of operations. The heat of braking wears out the brake linings. The extent of fading will depend upon the braking torque to deeelerate the heavy loads nid frequeney of its operations. They mtiy also need replaeement of the brake linings, similar to an automotive vehiele. 

Fig. 6 Modelled contributions from brake wear over Europe (LOTOS-EUROS model [30])...

Gietl JK, Lawrence R, Thorpe AJ, Harrison RM (2010) Identification of brake wear particles and derivation of a quantitative tracer for brake dust at a major road. Atmos Environ 44 (2) 141-146... 

Country Traffic situation Brake wear (mg/km/veh.) Resuspension (mg/km/veh.) Reference... 

Similarly, different results have been found for the impact of brake wear particles. While unequivocally a strong enrichment of brake-related chemical trace elements (Sb, Ba, Cu) is found at trafficked sites [63], the quantification of overall PM contribution from brake wear is associated with uncertainties. An even wider range of emission factors was found for re-suspension of road dust (cf. Table 4). It should be noted that re-suspension may be a strong source of PM during wintertime when de-icing salt is spread out. For a traffic site in southern Germany exceedance of the daily PM limit value could be tracked back to road salting in 12 of 43 cases [66]. 

Bukowiecki N, Lienemann P, Hill M et al (2009) Real-world emission factors for antimony and other brake wear related trace elements size-segregated values for light and heavy duty vehicles. Environ Sci Technol 43 8072-8078... 

Gaeg B, Cable S, Mulawa P, Geoblicki P, Iaeoo C and Pare GA (2000) Brake wear particulate... 

Transportation source emissions occur in two categories (1) vehicle exhaust and (2) vehicle-related particles from tire, clutch, and brake wear. Engine-related particulate emissions are composed primarily of lead halides, sulfates, and carbonaceous matter and are mostly smaller than 1 )U,m in diameter. About 40% of particles from tire wear are less than 10 fxm (about 20% are less than 1 /xm) and are primarily carbon. Particles from brake linings are less than 1 fxm and are composed mainly of asbestos and carbon. 

Fe Motor oil tire wear brake wear Garg et al. (2000)... 

Mn Brake wear resuspension of road dust and fugitive Allen et al. (2001), Gillies et al. 

Cu Brake wear tire wear wheel bearings fuel and Cadle et al. (1997), Westerlund... 

Kupiainen et al. 2005). Iron emissions originate from the resuspension of road dust as well as from the abrasion of road construction material additionally particles liberated from processes such as engine and brake wear have to be considered (Garg et al. 2000). These supplementary iron sources are responsible for the different size distribution of iron emissions compared to the results for Ca, Mg and Si, Al emissions. 

Real-world emission rates of in-use motor vehicles (road traffic) can be quantified by measurements in road mnnels. The results reported for particle mass emissions in PMio varied from several mg veh km to some hundred mg veh km , with reduced amounts for the fine particle fraction PM2.5. The particles released mainly consist of EC, OC, soluble ions (NHj, S04 , NOs ) and mineral components (Si, Fe, Ca, Al, Mg). Trace metal emissions (Ba, Co, Cr, Cu, Mn, Ni, Pb, Sb, Sn, Sr, Ti, V, Zn) contribute usually for less than 1 % of total emissions in all size fractions. Observed particulate vehicle emissions could be attributed to several tailpipe and non-tailpipe sources. The main part of carbon emissions may be contributed to tail-pipe exhaust fraction, whereas the non-carbon emissions are most likely non-exhaust derived components. PMjo emissions are usually dominated by resuspended matter as well as by brake wear, whereas fine particles (PM2.5) are mainly derived from combustion processes. 

Fraser M, Cass G, Simoneit B (1999) Particulate orgartic compounds emitted from motor vehicle exhaust in the atmosphere. Atmos Environ 33 2715—2724 Garg B, Cadle S, Mulawa P, Groblicld P, Laroo C, Parr G (20(X)) Brake wear particulate matter emissions. Environ Sci Technol 34 4463-4469... 

This Seeman Composites Resin Infusion Process (SCRIMP) has been used to manufacture corrosion resistance bus shells (Chapter 5). North America Bus Industries (NABI) of Anniston, AL uses glass fiber-polyester plastic material from TPI Composites of Warren, RI. These new buses weigh about 10,000 kg (22,000 lb) that is 3200 kg (7000 lb) lighter than steel units. Lighter weight results in reduced axial loads, brake wear, etc. and improved fuel efficiency. 

Abu-Allaban, M., GiUies, J.A., Gertler, A.W., Clayton, R., Proffitt, D., 2003. Tailpipe, resuspended road dust, and brake-wear emission factors from on-road vehicles. Atmos. Environ. 37, 5283-5293. 

This part of the regulations, along with Appendix G, provides the standards that the parts must meet at all times. Brake wear hmits, brake freeplay, tire wear hmit, windshield condition, etc. are all covered in these regulations. 

When the press reaches bdc, the clutch must disengage the flywheel to remove the source of power. The brake then engages, holding the press ram stationary in the bdc position. Since the material shrinks in the thickness direction upon cooling, the pressure is reduced thus permitting the press ram to restock readily without excessive clutch wear on the flywheel face. Brake wear is also minimized since the plastic material acts as a shock absorber as it is contacted by the plunger. 

---