Nanomaterials: Organic and Inorganic for Next Generation Diesel Technologies

Randy  Vander Wal, USRA

Nanoscale materials are redefining the relation between material composition, size and properties.  Chemical properties (e.g. reactivity) and physical properties (e.g. surface area) become a strong function of size at the nanoscale. This presentation will highlight applications of organic and inorganic nanomaterials to heavy-duty diesel trucks and include selected examples from the author’s work.  Selected technologies include catalysis, composite materials, energy storage, sensors, thermal management, and tribology.

Catalysis is central to particulate and NOx after-treatment systems.  A prime example of reducing materials to nanoscale and realizing new properties is catalysis by nanoscale gold.  Au nanoparticles supported on oxides such as CeO2, TiO2 and Fe2O3 offer ambient temperature oxidation of CO, volatile organic compounds (VOCs) and potentially exhaust hydrocarbons.

Lightweight materials will reduce weight significantly yielding substantial benefits in fuel efficiency with reduced emissions.  Composites with substantial gains in Young’s modulus, tensile strength, and EM shielding may be realized in polymeric composites using carbon nanotubes as an interfacial modifier rather than bulk filler. 

Advances in energy storage include batteries, ultra-capacitors.  These can support lighting, appliances, a starter, cooling fans, transmission and hydraulic systems, fuel and air handling systems and ultimately enable hybrid systems.  Towards these goals, substantial gains in Li ion battery cathode and anode materials have been realized using carbon nanofibers, coating processes and including elements such as tin and silicon.

With regards to overall system integration and control, sensors will play a prominent role.  With ultrahigh surface exposure relative to bulk material, nanoscale materials are exceedingly sensitive to gas adsorption.  Exploitation of nanoscale properties will lead to new NOx sensors and in-cylinder oxygen sensors.  Examples include catalyst coated metal oxide semiconductors capable of ambient temperature operation.  In contrast SiC MOSFETs offer high temperature capability for measuring fuel/oxygen ratio. 

Thermal management will benefit from nanofluids.  Nanofluids can increase thermal conductivity and reduce radiator and heat exchanger size.  Carbon-based nanofluids using nano-onions and carbon nanotubes have increased water conductivity by ~ 20%.
Lubrication is critical to many engine components and powertrain systems.  Nanolubricants can bridge the gap between fluid and solid materials.  As additives with liquids or greases, synergistic properties may be realized, particularly in boundary-phase lubrication.  Improved coating formulations and properties can reduce or eliminate fretting and pitting.  Results with nanocarbons show superior performance relative to graphite, diamond like carbon (DLC) and even Teflon