Environmental Engineering Reference
In-Depth Information
The interesting items in Table 1.6 are that customer expectations for price,
operating costs and ride and handling must be comparable to a CV. In comparison
the economy goals are very straightforward as noted in Table 1.7.
Table 1.7 Vehicle economy goals (US PNGV Goal 3)
Attribute
Baseline
vehicle
Weight-reduced
baseline vehicle
Hybrid
vehicle
PNGV
goal
Fuel economy (mpg)
26.7
<
65
80
80
2,300
1,875
Fuel usage during lifetime of
150 000 mi (gallons)
5,600
1,875
3,300
3,725
Lifetime fuel savings over
baseline (gallons)
-
3,725
The fuel savings are significant when taken over the lifetime of the vehicle (~6,000
operating hours). The three concept vehicles that were developed under PNGV (ended
in 2002) were the GM Precept, Ford Prodigy and DaimlerChrysler ESX3.
1.4.2 Engine downsizing
In a comparative study of these PNGV hybrids and the Toyota Prius and Honda
Insight, Jim Walters
et al.
[10] compared the relative sizes of the vehicles
(Figure 1.17) and the amount of engine downsizing (Figure 1.18).
5.50
5.30
5.10
4.90
4.70
4.50
4.30
4.10
3.90
3.70
3.50
800
1,000
1,200
1,400
1,600
Curb weight (kg)
Non-HEV
HEV
Linear fit (Non-HEV)
Figure 1.17 Comparison of vehicle length to curb weight (Delphi Automotive,
with permission)
Figure 1.17 reveals that, as a rule, the hybrids are distinctly mass reduced in
comparison to their CV counterparts. A linear regression through the CV length/
curb weight scatter plot shows that all the hybrids lie above the trend in terms of
