A special Lenton furnace with integral weighing system has provided Jaguar and Land Rover with state-of-the-art facilities for measuring the soot content of exhaust filters on diesel-engined vehicles
The soot content of diesel particulate filters (DPF) is a key indicator of engine performance.
Knowing the quantity of soot generated by different driving cycles over specific lengths of time allows design and development engineers to optimise engine performance.
Euro stage 5, due to come into force in 2009, specifies a maximum particulate output from diesel engines of 5mg/km - a performance that most Jaguars and Land Rovers already achieve.
The Lenton furnace has been designed to remove moisture and other contaminants from the accumulated deposits in a DPF, so that they can be weighed and compared with other samples very accurately and with precise repeatability.
The maximum soot content of a filter weighing 15kg is about 40g but may be only 4g, so very accurate equipment is needed to measure the relatively small differences generated by different driving cycles.
The equipment consists of a work chamber 750mm wide x 300mm high x 1600mm long with elements mounted in the base and the lid.
Maximum operating temperature is 1000C, with an eight-segment PID instrument allowing various processing programmes to be pre-set and run automatically.
A weighing system is incorporated within the furnace base, with a cradle in the chamber supporting the item being processed.
The instrumentation provides continuous displays and hard-copy records of temperature, weight and time.
Drying the soot in a DPF typically takes around five hours at 100C.
The furnace is also used for removing binders, oils and other volatiles and for regenerating DPFs by burning off all contaminants, for which Lenton has incorporated an air supply linked to the equipment's temperature controller.
These processes require temperatures around 680C and last up to 20 hours.
