Assessment of Fuel Economy Technologies for Light-Duty Vehicles (2011)
Chapter: Appendix G: Compression-Ignition Engine Replacement for Full-Size Pickup/SUV
G
Compression-Ignition Engine Replacement for Full-Size Pickup/SUV
The analysis and discussion for the main part of Chapter 5 were based on two vehicle classes—namely, a midsize sedan such as the Accord, Camry, Fusion, or Malibu and a midsize SUV such as the Durango, Explorer, or Trailblazer. To enable projections for the entire range of vehicle classes discussed in Chapter 9, it was necessary to create an additional engine specification to provide a CI replacement for the 5.3- to 6.2-L V8 SI engines which would be found in full-size body-on-frame pickup trucks such as the F150, the Silverado, and the Ram 1500 and SUVs such as the Expedition and Tahoe. Table 5.5 in Chapter 5 described a V6 CI engine with displacement between 2.8 and 3.5 L appropriate for midsize SUVs and midsize pickup trucks. For cost reasons, there is a range of displacements for which OEMs would tend to design and build V6 rather than V8 engines since V6s require fewer parts. For CI engines, this V6 range would be from about 2.9 L to perhaps 4.5 L. It was therefore assumed in this additional analysis that the V8 SI engines typically used in full-size pickups would be replaced by a V6 CI engine as long as the torque and power required for equal performance could be achieved. With a base-level specification at a specific torque of 160 N-m/L, the displacement required for a CI V6 to replace an SI V8 of the displacement range 5.3-6.2 L would be 4.4-5.2 L, which is really too large for the V6 configuration. However, from a cost point of view, the V6 configuration would be preferable to a V8 if a V6 concept could be identified that meets the requirements. If no base-level configuration were considered, an advanced-level V6 of 3.5 L could easily provide sufficient torque to replace a 6.2-L SI V8 and could be manufactured with the same set of tooling as the V6 engine whose cost increments are described in Tables 5.5 and 5.8. Therefore, for the full-size pickup class of vehicles, it was assumed in this analysis that the CI replacement for SI V8 engines would be a V6 of displacement up to 3.5 L with advanced-level technology. Cost estimates for such an engine are shown in Tables G.1 to G.3.
TABLE G.1 Incremental CI-Diesel Engine Cost Estimations to Replace SI MPFI OHV Two-Valve 5.3- to 6.2-L V8 Engine in a Full-Size Body-on-Frame Pickup (e.g., Silverado and Ram) or SUV with a 3.5-L V6 DOHC CI
|
50-State Saleable ULEV II 3.5-L V6 DOHC CI-Diesel Engine, Baseline: SI Gasoline OHV 4-V 5.3- to 6.2-L V8 |
Estimated Cost Versus Baseline ($) |
|
Common-rail 1,800 bar piezo-actuated fuel system with six injectors (@$75), high-pressure pump ($270), fuel rail, regulator and fuel storage upgrades plus high-energy driver upgrades to the engine control module. Credit for MPFI content deleted ($48). |
911 |
|
Series sequential turbocharging: One VGT with electronic controls and one fixed-geometry turbocharger with active and passive bypass valves necessary to match high EGR rates at low load conditions ($750). Water-air charge air cooler, circulation pump, thermostat/valve, and plumbing. Engine downsizing credit from V8 ($200).a |
830 |
|
Upgrades to electrical system: starter motor, alternator, battery, and 1.5-kW supplemental electrical cabin heater as is standard in Europe ($99). |
167 |
|
Cam, crank, connecting rod, bearing, and piston upgrades, oil lines ($62) plus NVH countermeasures to engine ($47) and vehicle ($85). |
194 |
|
High- and low-pressure EGR system to suppress NOx at light and heavy loads. Includes hot-side and cold-side electronic rotary diesel EGR valves plus EGR cooler and all plumbing. |
226 |
|
Add remaining components required for advanced-level technology (details in Table G.3). |
308 |
|
Emissions control system including the following functionality: DOC, CDPF, selective catalytic reduction (SCR), urea dosing system ($363). Stoichiometric MPFI emissions and evaporative systems credit ($343). |
1,040 |
|
On-board diagnostics (OBD) and sensing, including four temperature sensors (@$13), wide-range air/fuel ratio sensor ($30), NOx sensor ($85), two-pressure sensing glow plugs (@$17), six glow plugs (@$3), and Delta-P sensor for DPF ($25). Credit for four switching O2 sensors (@$9). |
227 |
|
Total variable cost with credits for SI parts removed excludes any necessary transmission, chassis, or driveline upgrades. |
3,903 |
|
NOTE: Aftertreatment system cost estimates reflect April 2009 PGM prices. Estimates derived from Martec (2008). CDPF, catalyzed diesel particulate filter; CI, compression ignition; DOC, diesel oxidation catalyst; DOHC, dual over head cam; DPF, diesel particulate filter; DPF, diesel particulate filter; EGR, exhaust gas recirculation; MPFI, multipoint fuel injection; NVH, noise, vibration, harshness; OBD, on-board diagnostics; OHV, over head valve; PGM, platinum group metals; SCR, selective catalytic reduction; SI, spark ignition; ULEV II, ultra-low-emissions vehicle; VGT, variable geometry turbocharger. a Credit for downsizing from V8 to V6 referred to DOHC 4-V V8 downsized to DOHC 4V V6. In this case, credit used by Martec was reduced from $270 to $200 since the parts removed from an OHV 2-V V8 would cost less than those removed from a DOHC 4-V V8. |
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TABLE G.2 Cost Estimates of Exhaust Emissions Aftertreatment Technologies Capable of Enabling Tier 2, Bin 5 Compliance
|
Item |
Midsize Car (e.g., Malibu), Catalytic Device Sizing Based on 2.0-L (April 2009 PGM prices) ($) |
Midsize SUV (e.g., Explorer), Catalytic Device Sizing Based on 3.5- L (April 2009 PGM prices) ($) |
Full-Size Pickup (e.g., Explorer), Catalytic Device Sizing Based on 4.4-L (April 2009 PGM prices) ($) |
|
DOC 1 |
|
|
|
|
Monolith and can |
52 |
52 |
52 |
|
PGM loading |
139 |
200 |
252 |
|
DOC 2 |
|
|
|
|
Monolith and can |
Not used |
52 |
52 |
|
PGM loading |
Not used |
70 |
87 |
|
EGR catalyst |
|
|
|
|
Monolith and can |
7 |
Not used |
Not used |
|
PGM loading |
13 |
Not used |
Not used |
|
Coated DPF |
|
|
|
|
Advanced cordierite brick and can |
124 |
270 |
270 |
|
PGM loading |
131 |
26 |
33 |
|
NSC system |
|
|
|
|
Catalyst brick and can |
114 |
Not used |
Not used |
|
PGM loading |
314 |
Not used |
Not used |
|
SCR-urea system |
|
|
|
|
SCR brick and can |
39 |
274 |
274 |
|
Urea dosing system |
Passive SCR |
363 |
363 |
|
Stoichiometric gasoline emissions and evaporative system credit |
−245 |
−343 |
−343 |
|
Emissions system total |
688 |
964 |
1,040 |
|
NOTE: This table complements Table 5.5. Compared to Table 5.5, the columns reflecting November 2007 PGM prices (Columns 2 and 4) have been removed and a new column, Column 4, was added. This column reflects the aftertreatment system cost estimate for the exhaust flow rates of a larger base-level V6 CI engine (i.e., 4.4 L) suitable for replacing 5.5- to 6.2-L two-valve OHV V8 SI engines with 3.5-L advanced-level technology CI engines. Note that, as discussed in Chapter 5, it was assumed that the aftertreatment component sizes for the 3.5-L advanced-level V6 are equal to those of a base-level 4.4-L V6 because the power levels for these two engines would be the same, thus requiring the same exhaust flow rates. All cost estimates are based on April 2009 PGM commodity prices. Column 4 provides the estimate used for the aftertreatment costs in Table G.1. |
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TABLE G.3 Estimates of Incremental Costs to Implement Developments Whose Estimated Fuel Consumption Reduction Gains Are Summarized in Table 5.2
|
Item |
Midsize Car (e.g., Malibu) 1.6-L L4 |
Midsize SUV (e.g., Explorer) 2.8-L V6 |
Full-size Pickup (e.g., Ram 1500) 3.5-L V6 |
|
|
Downsize engines 2-L L4 to 1.6 L, 3.5-L V6 to 2.8 L, 4.4-L V6 to 3.5 L |
50 |
75 |
75 |
Higher load capacity rod bearings and head gasket for higher cylinder pressures (~$12.50/cylinder) |
|
Two-stage turbocharger system |
375 |
545 |
0a |
Additional air flow control valves, piping, cost of additional turbo, water-to-air intercooler with control valve, separate pump |
|
Dual-pressure oil pump |
5 |
6 |
6 |
Switchable pressure relief valve for high or low oil pressure |
|
Nonrecirculating LP fuel pump |
10 |
12 |
12 |
Variable output LP pump controlled by HP pump output |
|
Low-pressure EGR |
— |
95 |
95 |
Additional piping (~$20) and valves (e.g., integrated back pressure and LP EGR rate ~$75), much more difficult to package for V6 engine with underfloor DPF, cost for L-4 already included in Table 5.4 |
|
Direct-acting HP (maximum injection pressures > 2,000 bar) piezo injectors |
80 |
120 |
120 |
$20/injector, benefits derived from combination of higher rail pressure and more injector controllability |
|
Total |
520 |
853 |
308 |
|
|
NOTE: These developments are CI-diesel downsizing from base level to advanced level, thermodynamic improvements, friction reduction, and engine accessory improvements. Total for full-size body-on-frame pickup ($308 at bottom of Column 4) used in Table G.1. FC, fuel consumption. aTwo-stage turbo system already comprehended in Table G.1. |
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