Page 232 - Biofuels Refining and Performance

Ethanol and Methanol as Fuels in Internal Combustion Engines 215

8
Lean
Rich
6 Methanol
CO (% Volume) 4 Petrol

2

0.6 0.8 1.0 1.2 1.4
Equivalence ratio
Figure 7.17 Effect of equivalence ratio on CO.

occurs while operating at a lean A:F ratio, whereas in an engine using
alcohol, the engine can manage to handle leaner mixtures without any
misfire. Important objectionable emissions are CO, HC, NO , and alde-
x
hydes. The effect of equivalence ratio on all these emissions for petrol
and methanol are shown in Figs. 7.17 through 7.20.

2000
Lean
Rich
1600
Petrol
HC (ppm) 1200

800
Methanol

400

0.6 0.8 1.0 1.2 1.4 1.6
Equivalence ratio
Figure 7.18 Effect of equivalence ratio on HC.