Fuels in Transportation - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 17

Table 2.4 Unleaded gasoline reference fuel in the USA

CARB a Parameter Unit EPA

Ambient Cold CO

low octane
number

Cold CO
high octane
number

Octane (R ? M)/2 93 87 ± 8

RVP b psi

(kPa)

8-9.2
(55.2-63.4)

11.5 ± 3 11.5 ± 3 6.7-7.0

(46.8-48.3)

RVP Evap psi

(kPa)

8.7-9.2
(60-63.4)

7
(46.3-48.3)

T10 F

(C)

120-135
(48.9-57.2)

98-118
(36.6-47.7)

105-125
(40.5-51.6)

130-150
(54.4-65.5)

T50 F

(C)

200-230
(93.2-110)

178-214
(81.2-101)

195-225
(90.5-107.1)

200-210
(93.2-98.8)

T90 F

(C)

300-325
(148.8-162.6)

316-346
(157.6-
174.3)

316-346
(157.6-174.3)

290-300
(143.2-148.7)

FBP F

(C)

415
(212.6)

413
(211.5)

413
211.5

390
(198.7)

Aromatics % vol 35 26.4 ± 4 32 ± 4 22-25

Olefins % vol 10 12.5 ± 5 10 ± 5 4-6

Benzene % vol 0.8-1.0

15-80 c 15-80 c 15-80 c Sulfur ppm 30-40

g gal -1
(g l -1 )

Lead 0.05

(0.013)

0.01
(0.0026)

0.01
(0.0026)

0.01
(0.0026)

g gal -1
(g l -1 )

Phosphorus 0.005

(0.0013)

0.005
(0.0013)

0.005
(0.0013)

0.005
(0.0013)

a

Californian Air Resources Board

b

RVP for altitude testing: 7.6-8.0 psi or 52-55 kPa

c

Road fuel will contain 30 ppm on average and a maximum of 80 ppm

Table 2.6 presents the main physical and chemical properties of diesel refer-
ence fuel [ 14 ].
Table 2.7 shows the quality of diesel reference fuels in the USA for vehicles
with a self-ignition engine [ 15 ].

2.2.4 Products of Natural Gas

The most important fuels made from natural gas are Compressed Natural Gas
(CNG) and Liquid Natural Gas (LNG). CNG is predominantly methane. For its use
in motor vehicles, CNG must be dried, compressed to a pressure of 250 bar
(522,136 lbf ft -2 ), and filled into the motor vehicle's tank. Internal combustion
engines must be adapted to be able to use CNG [ 16 ].