To improve gearset performance, gears can be subjected to surface treatments. One possible surface treatment is TCG, Triboconditioning for Complex Geometries. This paper investigates efficiency and pitting resistance of two types of TCG treatments on powder-sintered gears, compared to an untreated reference. Experimental testing is performed in an FZG gear test rig with an efficiency and a pitting setup, respectively. Efficiency is calculated from the measured outside torque, and pitting evolution is monitored by scanning the tooth surface after each load cycle. The results indicate that TCG increases efficiency. The results concerning pitting resistance are inconclusive with previous studies and to better understand the mechanisms involved, further tests are suggested.

Airborne wear particle emissions from dry clutches have been investigated in terms of particle mass and number concentration, size distribution, and chemical composition of a single clutch material. This paper presents a detailed continuation of the investigation. Clutch plates of two different friction materials, i.e., from different manufacturers but for the same automobile applications, are tested and compared under different running conditions. Online measurements are made of number and mass concentration as well as size distribution. Chemical composition is analysed of both collected particles and used and unused clutch disc surfaces. Particle morphology is studied using a transmission electron microscope. Results indicate that emission profiles of the two materials are different in terms of concentrations and composition, but both materials emit fine and ultrafine particles, and the emitted particles consist of elements like Al, Fe, Cu, and Ba.

Road traffic is an important source of urban air pollutants. Due to increasingly strict controls of exhaust emissions from road traffic, their contribution to the total emissions has strongly decreased over time in high-income countries. In contrast, non-exhaust emissions from road vehicles are not yet legislated and now make up the major proportion of road traffic emissions in many countries. Brake wear, which occurs due to friction between brake linings and their rotating counterpart, is one of the main non-exhaust sources contributing to particle emissions. Since the focus of brake wear emission has largely been on particulate pollutants, little is currently known about gaseous emissions such as volatile organic compounds from braking and their fate in the atmosphere. This study investigates the oxidative ageing of gaseous brake wear emissions generated with a pin-on-disc tribometer, using an oxidation flow reactor. The results demonstrate, for the first time, that the photooxidation of gaseous brake wear emissions can lead to formation of secondary particulate matter, which could amplify the environmental impact of brake wear emissions.

Modern gearing applications, in particular electrification, impose new challenges in many different fields of engineering and research. In specific, new demands are imposed on gears, including higher rotational speed, lower noise acceptance, and increased efficiency, as well as increased resistance against pitting and scuffing. To meet these demands, a better understanding of gear contacts is needed. The Eurostars project Effigears proposes a novel multi-perspective methodology for assessment of gear efficiency and contact analysis. The methodology consists of using a novel surface treatment method, Triboconditioning (R), implemented in a streamfinishing process, surface measurements using a scattered light method, experimental testing using the standardized FZG test rig, and contact simulations using a novel thermal elasto-hydrodynamic lubrication tool. It is found, in preliminary tests, that enhanced gear performance may be enhanced due to Triboconditioning (R) surface treat-ment. Findings also include better understanding of how surface characteristics and lubricants affect scuffing and pitting, and the effect of load distribution on gearset behavior.