Unburned hydrocarbon emission
600
500
400
300
200
100
0 0
100
200
300
400
500
600
Brake mean effective pressure (KN/m
2 )
Diesel fuel
Rapeseed oil-advanced
Rapeseed oil-standard
31
Vegetable Oils
0
5
10
15
20
25
30
35
Brake thermal efficiency (%)
0:100 (R:D)
25:75 (R:D)
50:50 (R:D)
75:25 (R:D)
100:0 (R:D)
0
100
200
300
400
500
600
700
BMEP (kN/m 2 )
Figure 2.2
Brake thermal efficiency of rubber seed oil–diesel blends.
Figure 2.3
Unburned hydrocarbon emissions of rapeseed oil. (From Nwafor, O. M. I., Rice, G., and
Ogbonna, A. I., Renewable Energy, 21, 433–44, 2000. Reproduced with permission from Elsevier
Publications.)
operation had showed the highest concentrations of HC in the exhaust
(Figure 2.4). The advanced injection unit had given a marginal increase in
HC emissions over the standard injection timing unit. The HC emissions
may be increased by several factors such as quenched flame, lean combustion, cold starting, and poor mixture preparation. Moreover, high viscosity
of vegetable oil might have provided a good sealant between the piston rings