Both modes of combustion have been studied at our laboratories in Shock Waves. Typical injection pressures at which our Diesel fuel injector is operated is about 1100bar. To study the combustion of fuel additives alone which have lower viscosities, a different injector which operates at lower injection pressures is sufficient. Images were recently obtained using high-speed video photography. This shock tube can withstand higher pressures.
Optical access is via quartz windows in the end plate and in ports located near the end plate.
Induction delays are measured using photomultipliers whereas the temperature may be measured using a three-colour pyrometer. Laser attenuation and scattering techniques have been used but are in continual development. Several pressure gauges are used in all of the shock tubes to obtain a pressure history of each test which enables the shock velocities to be calculated. The combustion of commercial Diesel fuels may be studied using these techniques. Additives are used to improve the ignition quality and cleanliness of some fuels.