Effects of Current and Prior Operating Conditions on Particulate Matter Emissions from a Diesel Engine Operated on Heated Rapeseed Oil

This paper reports on particulate matter (PM) emissions measurement on a turbocharged direct injection tractor diesel engine with a mechanically controlled injection pump operated alternately on diesel fuel and fuel-grade rapeseed oil heated to 70-90°C. PM emissions were measured using standard gravimetric method, with supplemental online measurements with a semi-condensing integrating forward laser beam scattering detector and a measuring ionization chamber. All three measurements were in good agreement and show that the operation on heated rapeseed oil results, compared to operation on diesel fuel, in moderate decreases in PM emissions at moderate and higher speeds and loads, and substantial increases in PM at low speeds and loads. Low-speed, low-load operation on vegetable oil therefore needs to be addressed even if the engine appears to produce acceptable emissions during standard tests. PM emissions from rapeseed oil combustion were strongly influenced by prior operating conditions of the engine over a course of tens of minutes, showing that careful and consistent preconditioning is essential for any emissions tests of vegetable oil powered engines.