Nanofibers for automotive
There are many potential applications of nanofibers in the automotive industry, impacting vehicle performance, fuel efficiency and passenger comfort.
Nanofibers can be used in the following applications:
- Noise absorption
- Filters (engine intake, fuel, cabin air, exhaust)
- Batteries for hybrid and electric cars
The primary benefits of nanofibers in these applications are:
- Fuel savings - efficient and lightweight materials
- Less pollution, higher combustion efficiency - cleaner air and fuel into the engine
- Cleaner environment inside and outside
- Short charge time for electric cars
The filtration industry was the first to adopt nanofibers in wide scale production and understand the theoretical implications of finer fibers in filtration media. Nanofibers offer high initial efficiency for small particles and fractional efficiency drastically increases when nanofibers are applied to a substrate.
Cabin filtration systems protect drivers and passengers from the stream of airborne pollutants in the passenger compartment. The protection needs vary somewhat for different types of vehicles and can require more emphasis on different types of pollutants, such as dust, pollen, bacteria, mold spores and many others. Any machine that uses air in a combustion chamber to burn liquid or gaseous fuel must filter the air, to prevent ingress of solid particles that would cause wear in the piston-cylinder system or of the blades of a turbine. The air entering the engine must be clean, free of debris, and as cool as possible. Air intake filtration reduces component wear, improves engine performance and lengthens engine life.
In both air-intake filtration and cabin filtration, the small diameter of nanofibers, low weight and high porosity create and effect called “slip flow”, allowing lower air flow resistance, as well as higher mass flow close to the fibers, leading to increased filtration efficiency at a lower pressure drop. This results in longer filter service life, lower energy costs due to a low increase pressure drop over the life of the filter, less cleaning pulse cycles and reduced equipment downtime as fewer filter changes are required.
Large auto makers spend countless hours attempting to quantify the Noise, Vibration and Harshness (‘NVH’) characteristics of their vehicles. NVH can be quantified by cabin decibel levels but also involves difficult to measure activities such as reducing rattles and increasing vehicle comfort. It’s always possible to make a vehicle quieter by increasing the vehicle’s weight – but doing so makes the vehicle costs more and uses more fuel. NVH qualities of the vehicle can be improved while also reducing vehicle weight by incorporating nanofiber coated material with traditional sound absorption material. Nanofibers most effectively address frequencies below 1,000 Hz, an important range for passenger comfort.
Uses for nanofibers in solar cells, lithium-ion batteries and fuel cells as discussed in the Nano for Energy section will play an important role in alternative energy vehicles. Nanofibers used in catalytic converters may also improve air quality as discussed in the Nanofibers for Air section.
