. "4 Spark-Ignition Gasoline Engines." Assessment of Fuel Economy Technologies for Light-Duty Vehicles. Washington, DC: The National Academies Press, 2011.
The following HTML text is provided to enhance online
readability. Many aspects of typography translate only awkwardly to HTML.
Please use the page image
as the authoritative form to ensure accuracy.
Assessment of Fuel Economy Technologies for Light-Duty Vehicles
Technologies
Consumption Benefit
Incremental Cost
Comments
I4
V6
V8
I4
V6
V8
SI Techniques
(%) Range
(%) Range
(%) Range
Low
High
Low
High
Low
High
VVT—dual cam phasing (DCP)
DCP
1.5-2.5
1.5-3.0
1.5-3.0
52.5
105
105
Implementations include exhaust only and dual-cam phaser (DCP)
Manufacturer cost estimate of $35/phaser
Continuously variable valve lift (CVVL)
CVVL
3.5-6.0
3.5-6.5
4.0-6.5
239
308
435
465
525
585
Short durations may reduce pumping loss, and the reduced lift is a consequence of this
As intake manifold vacuum vanishes, alternate means must be found to implement power brakes and PCV
CVVL features wide range of cam profiles
Manufacturer cost estimate of $300 for an I4, and $600 for a V-8
VVT—coupled cam phasing (CCP), OHV
CCP
1.5-3.0
1.5-3.5
2.0-4.0
52.5
52.5
52.5
Requires in block cam phaser
Manufacturer cost estimate of $35/phaser
Stoichiometric gasoline direct injection (GDI)
SGDI
1.5-3.0
1.5-3.0
1.5-3.0
176
293
254
384
443
527
Enables about +1.0 knock limited compression ratio
High pressure fuel pump increases parasitic loss
Increased volumetric efficiency increases pumping loss
Injector deposits formed upon hot shut down has been a traditional concern
Manufacturer cost estimates $80/cylinder and $136 for injector noise abatement items
Technologies
Consumption Benefit
Incremental Cost
Comments
I4
V6
V8
I4
V6
V8
SI Techniques
(%) Range
(%) Range
(%) Range
Low
High
Low
High
Low
High
Turbocharging and downsizing
TRBDS
2.0-5.0
4.0-6.0
4.0-6.0
555
735
−50
308
788
1185
Vehicle launch performance will likely be compromised
Piston underside oil squirters, an oil cooler, and an intercooler may contribute to system merits
Dual scroll and VNT units will improve vehicle launch performance
Manufacturer estimates $550-$920 for a fixed geometry system
