Johnson Matthey Technology Review - Volume 61, Issue 4, 2017

China has been the world’s largest new vehicle market since 2009 and new vehicle sales exceeded 28 million in 2016, among which more than 87% were light-duty vehicles (LDV). In order to reduce emissions and control air pollution China has recently adopted the China 6 emissions standard for LDV which is 50% more stringent than China 5. Besides strengthening the tailpipe emissions limits, China 6 changes the emissions test driving cycle to the Worldwide Harmonised Light-Duty Vehicle Test Cycle (WLTC), adds real road emissions requirements and significantly strengthens evaporative emissions control. This paper introduces the standard development background, summarises the key technical improvements and discusses the areas for further improvements in future.

We herein report on the effect of gamma ray radiation on platinum, osmium, rhodium and palladium salt solutions for synthesis of nanoparticles. Pt, Os, Rh and Pd salt solutions were exposed to intense gamma ray irradiation with doses varying from 70 to 120 kGy. The metal ion salt solutions were easily converted into metal nanoparticles using this radiolysis method. The radiolytic conversion effect produced metal nanoparticles suspended in solution. For Pt, Pd and Rh a metal coating on the edges of the polypropylene tube used as a container was unexpectedly observed but not for the Os solution. X-Ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) analyses confirmed that both the coating and the metal nanoparticles correspond to the pure metal coming from the reduction of the initial salt. Quantitative analysis of the XRD patterns shows information about the size and stress of the converted metals. The production of a metal coating on polypropylene plastic tubes by gamma ray irradiation presents an interesting alternative to conventional techniques of metal deposition especially for coating the inner part of a tube.

Methanol is increasingly being looked at as a way to reduce the emissions potential of transport fuel. It may be used in place or in addition to gasoline fuel, for example. The amount of greenhouse gas (GHG) emitted in producing methanol can vary hugely according to the syngas generation technology selected and the choice of electrical or steam turbine drive for compressors and pumps. This paper looks at the impact of these technology choices on GHG emissions and how the carbon intensity of methanol used as a transport fuel compares to the carbon intensity of other hydrocarbon fuels. It is found that methanol produces lower well to wheel emissions than gasoline under all production methods studied and can even produce lower GHG emissions compared to ethanol as a fuel supplement. However, the same is not always true if methanol is used to produce gasoline from natural gas.

Driven by concerns on deteriorating ambient air quality, measures are being taken across the world to adopt and enforce tighter vehicular emission regulations to minimise tailpipe unburned hydrocarbons, nitrogen oxides (NOx) and particulate matter (PM). In regions with advanced regulations, the focus is on limiting the pollutants under real-world or in-use driving conditions. Given the intensified effort to curb global warming and limit fossil fuel use in the transportation sector, several countries have adopted targets on tailpipe carbon dioxide emissions. This confluence of stringent regulations for both criteria pollutant and greenhouse gas (GHG) emissions is leading to a rapid adoption of advanced powertrains and aftertreatment technologies. This is a review of some of these recent advances pertinent to reducing vehicular emissions and developing improved aftertreatment solutions. The scope is limited to gasoline vehicles where the adoption of gasoline direct injection (GDI) and hybrid powertrain technologies is leading to significant shifts in the aftertreatment solutions. There is significant work being done to improve diesel aftertreatment systems especially in light of real-world driving emission (RDE) regulations. These are not covered here, rather the reader is referred to a previous article in this journal’s archive (1), and to a more recent review (2).