Investigation of first generation biofuels in diesel engines.

In an AC1W IDI Lister Petter diesel engine, ignition delay reduced exponentially with an increase in engine speed for hempseed oil (HSO), camelina seed oil (CSO) and rapeseed oil (RSO). The polyunsaturated fuels HSO produced ignition delays which were 0.6 to 12.4%, 18.7 to 32.1% and 10.8 to 26.8% longer than RSO, rapeseed methyl ester (RME) and mineral diesel (MD) fuel respectively whilst CSO produced ignition delays which were 0 to 9.8%, 18.4 to 29.1% and 11.8 to 24.8% longer than RSO, RME and MD fuel respectively. Ignition delays increased with a 5o Crank Angle (CA) advance in fuel injection timing by 2.7 to 19.2%, 0.9 to 11.1% and 0.12 to 17.0% for RSO, CSO and HSO respectively. A reduction in ignition delay was noted for RSO, CSO and HSO by 5 to 7.1%, 1.4 to 9.5% and 7.9 to 13.5% except above 3100rpm at 5oCA retarded fuel injection timing. Maximum power outputs of HSO (4.12kW), and CSO(4.38kW) were lower when compared with MD fuel (4.43kW) however maximum power outputs for RSO (4.47kW) and RME (4.63kW) were both higher when compared with MD fuel (4.43kW) at standard fuel injection timing. After 28 days HSO, CSO, RME and WCOME increased in acid value from 8.1 to 178.4% and peroxide value varied from -63.64% to 321.85%. Ignition delay, combustion chamber peak pressure signal and rate of pressure rise were unaffected by storage of the oils. Advancing fuel injection timing by 5oCA in a 1.5L Tempest (BMC) engine had no significant effect on the power, torque and BMEP for RME, NOx and smoke emissions increased by 10.7 to 41.5% and by 24.5 to 74.3% respectively and CO reduced by 14.4 to 21.6% at BMEP<250kPa; but mean CO was higher by 1.2 to 21.9% for RME for 500kPa>BMEP>250kPa. HSO and CSO gave 4.9% and 5.6% higher maximum power than RSO, 12.6% and 13.3% more than RME and WCOME and 17.4% and 18.1% more than MD fuel respectively in a 1.8L NA IDI Ford Courier. HSO used 2.6 to 15.9% and 1.8 to 11.2% more fuel than RME and WCOME respectively whilst CSO used 2.1 to 16.3% and 2.1 to 12% more fuel than RME and WCOME respectively except above 3700rpm. HSO and CSO used 9.1 to 42.6% and 0 to 43.1% more fuel than MD fuel for all engine speeds. Mean NOx increased by 11.4 to 40.2% for HSO and 15.7 to 35.1% for CSO above 1800rpm compared with RME. NOx was higher by 11.9 to 34.6% for HSO and by 16.2 to 29.7% higher for CSO for all engine speeds than WCOME. Both HSO and CSO increased NOx by 6.9 to 55.1% and 5.1 to 56.9% compared with MD fuel above 1800rpm. RME and WCOME gave 2.2 to 26.7% and 1.8 to 25% greater NOx respectively than MD fuel above 3750rpm. After 492kWh use, RME gave carbon deposits on cylinder head, valves, piston crown and fuel injector in a 2kW DI diesel generator and the top piston ring was seized. Carbon build up on the inlet valve and port was between 1.2 x 10-3 and 3.8 x 10-3mm/kWh. An exponential rise in lubricating oil consumption and fuel consumption after 288kWh indicated the start of engine wear out. Neoprene and reinforced polyurethane are not suitable materials for RME fuel lines. The use of 100% RME in a 1.3L TDI ESB fleet vehicle resulted in a reduction in the maximum power output (40.4kW) of 6.9% after 11023km (nine months) to 37.6kW whilst maximum power output (53.5kW) reduced by 4.4% to 48.75kW with the use of 30%RME/70% MD fuel in a 2.0L TDI ESB fleet vehicle after 22459km (nine months).