TABLE 5.8 Committee’s Estimates of Incremental Costs to Implement Advanced-Level Diesel Developments (downsizing, thermodynamic improvements, friction reduction, and engine accessory improvements) Whose Estimated Potential for Reducing Fuel Consumption Is Summarized in Table 5.2


Midsize Car (e.g., Malibu) 1.6-Liter I4

Midsize SUV (e.g., Explorer) 2.8-Liter V6


Downsize engines from 2-L I4 to 1.6-L I4 and from 3.5-L V6 to 2.8-L V6



Higher load capacity rod bearings and head gasket for higher cylinder pressures (~$12.50/cylinder)

Two-stage turbocharger system



Additional air flow control valves, piping, cost of additional turbo, water-to-air intercooler with separate pump, control valve

Dual-pressure oil pump



Switchable pressure relief valve for high or low oil pressure

Non-recirculating low-pressure (LP) fuel pump



Variable output LP pump controlled by high-pressure (HP) pump output

Cylinder pressure sensors

Two pressure-sensing glow plugs, one to sense fuel property differences, second to provide on-board diagnostics durability backup for first, already included for both I4 and V6 in Tables 5.3 and 5.4

Low-pressure exhaust gas recirculation (EGR)


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 diesel particulate filter, cost for I4 already included in Table 5.4

Direct-acting HP (maximum injection pressures >2,000 bar) piezo injectors



$20/injector, benefits derived from combination of higher rail pressure and more injector controllability





TABLE 5.9 Estimated Total Costs to Replace 2007 Model-Year SI Power Trains with Base- and Advanced-Level CI Power Trains for Example Midsize Sedan and Midsize SUV-Type Vehicles


Base-Level CI Engine

Advanced-Level CI Engine

Midsize Sedan



I4 engine

$2,393 (Table 5.4) or

$2,400 (when rounded to nearest $50)

$2,913 (Tables 5.4 and 5.8) or

$2,900 (when rounded to nearest $50)

DCT6/7a transmission

$140-$400 (Table 7.10)

$140-$400 (Table 7.10)


$2,550-$2,800 (when rounded to nearest $50)

$3,050-$3,300 (when rounded to nearest $50)

Midsize SUV



V6 engine

$3,174 (Table 5.5) or

$3,150 (when rounded to nearest $50)

$4,027 (Tables 5.5 and 5.8) or

$4,050 (when rounded to nearest $50)

DCT6/7 transmission

$140-$400 (Table 7.10)

$140-$400 (Table 7.10)


$3,300-$3,550 (when rounded to nearest $50)

$4,150-$4,450 (when rounded to nearest $50)

aNote that the higher of the two estimates shown in Table 7.10 is for a 6/7-speed dual-clutch transmission (DCT). In accordance with the potential fuel consumption reduction gains discussed in Table 5.2 due to transmission improvements, it was assumed that 7-speed versions would be used. Due to the wide range of cost estimates for DCTs as discussed in Chapter 7, no adjustment was made for the higher torque requirements of the V6 CI.

nology combinations for reducing the fuel consumption of 2007 model-year SI gasoline engine vehicles by equipping them with advanced CI diesel power trains.

Finding 5.1: By a joint effort between OEMs and suppliers, new emissions control technology has been developed to enable a wide range of light-duty CI engine vehicles to meet the 2010 Tier 2, Bin 5, LEV II emissions standards.

Finding 5.2: Replacing 2007 model year MPFI SI gasoline power trains with base-level CI diesel engines with advanced dual-clutch (automated manual) transmissions (DCTs) (6-speed) and more efficient accessories packages can reduce fuel consumption by an average of about 33 percent (or reduce CO2 emissions by about 23 percent) on an equivalent vehicle performance basis. Advanced-level CI diesel engines with advanced DCTs could reduce fuel consumption by about an additional 13 percent for larger vehicles and by about 7 percent for small vehicles with engine displacements less than 1.5 L.

Finding 5.3: The characteristics of CI diesel engines that enable their low fuel consumption apply over the entire vehicle operating range from city driving to highway driving, hill

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