iKey resultswww.vcr-i.com
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One of the automobile industry’s main priorities is to reduceengine cubic capacity (downsizing) and mean operating speed(downspeeding) in order to reduce vehicle fuel consumptionlevels. This is also the primary objective of MCE-5 VCRitechnology. To do this, it is necessary to reach the highestpossible specific torque and power with the shortest possibleturbo-lag, and the lowest possible specific consumption at highloads. With exceptional specific torque and power of 320 Nm/L and120 kW/L, MCE-5 VCRi surpasses all the existing fixedcompression ratio engines, and with 60 to 70% more torquethan will have future fixed compression ratio turbo GDI enginesplanned for the next decade (40 bar of BMEP vs. 25). The 120kW/L of specific power delivered by the twin turbo MCE-5 VCRiGDI is 20% higher than that of the best existing turbo GDIengines. These excellent specific performances are reached thanks toMCE-5 VCRi’s wide range, reduced friction and high loadcapacity MCE-5 transmission mechanism. These performances reflect the exceptional ability of MCE-5VCRi to downsize and downspeed car engines, resulting in asignificant decrease in fuel consumption and associated CO2emissions.DOWNSIZING - DOWNSPEEDING:180
02040608010012014016060050040030020010000100020003000400050006000Power (kW)
Torque (Nm)
Speed (rpm)MCE-5 VCRi GDI 1,484 cc - 2-stage turbocharger
The 1.5L MCE-5 VCRi prototypes deliver the torque of a naturally-aspirated 4.8L engine and the power of a 3.2L V6 enginei
www.vcr-i.com2There is no hard downsizing without high supercharging. MCE-5VCRi’s supercharging with two turbocompressors contributes toits efficiency, with both excellent isentropic efficiency andexcellent responsiveness to reach 80% of torque in under2seconds at 1500 rpm. Supercharging efficiency is one of the keys to the success of thistype of engine, with good exhaust temperature control, highefficiency at high loads and supercharging pressures in the orderof 4 bar of absolute pressure.HIGH EFFICIENCY SUPERCHARGING:
Particular attention was paid to the developmentof the two-stage supercharging of the MCE-5 VCRi.It comprises a low-pressure stage, a high-pressure stageand two air-water coolers positionedafter each compressor (intercooler, aftercooler)i
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3MCE-5 VCRi makes it possible to optimize the compressionratio according to speed and load, resulting in increasedthermodynamic efficiency and significantly improvedcombustion stability.On the compression ratio map, we can distinguish high-loadpoints for which the main objective is maximum torque and themost used, low-load points, for which the aim is to maximizeefficiency.COMPRESSION RATIO OPTIMIZATION:i
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The gains made by MCE-5 VCRi are more due to the repositioning of the engine’s operating points than to the improvement of the BSFC mapIn the driving cycle (example: NEDC), MCE-5 VCRi reduces vehicle fuelconsumption by combining the gains provided by downsizing-downspeeding with those provided by compression ratio optimization.MCE-5 VCRi’s limited friction losses also contribute to the results obtained.Note that the fuel consumption reduction is higher for powerful cars than forsmall ones.FUEL CONSUMPTION REDUCTION IN THE DRIVING CYCLE:
100 %
0 %10 %20 %30 %40 %50 %60 %70 %80 %90 %
VCRNAengineDownsizedVCRengine(turbo)TorquePumping lossesFriction lossesHeat lossesCombustion lossesOtto lossesRefNAengine+5% efficiency+32% efficiency
140
speed (kph)
Time (secs)Part Two - Extra UrbanPart One - Urban1201008060402000100200300400500600700800900100011001200New European Driving Cycle (NEDC)
403530252015105001000150020002500300035004000450050005500Engine speed (rpm)BMEP (bar)
400400400350350350320320320290290290270270270270270270250250250250290290
290320320Specific fuel consumption map of the MCE-5 VCRi 1.5L GDIand corresponding operating point of the MCE-5 demo caron the New European Driving Cycle (NEDC)
Steady state operating pointMax BMEP
Transient operating pointThe forecasted fuel consumption reductions refer to the NEDCVCR redefines the energy balance of enginesi
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Torque (Nm)
Power (kW) - emissions (g CO2/km)Power240
100120140160180200220700
0100200300400500600
OriginalV6Dieselbi-turboDW12BMCE-5bi-turboMPFI(2010)MCE-5bi-turboGDI(2010)MCE-5bi-turboGDI opti(2011)MCE-5bi-turboGDI optiVVAMCE-5bi-turboGDI optiVVAS&SMCE-5bi-turboGDI optiCAIS&SPower (kW)Torque (Nm)CO2/km - NEDC (g)155290233125370159160420160160470158180470155180470145180470138180470128Fuel consumption NEDCTorque
On a Peugeot 407 type vehicle, the most basic MCE-5 VCRi MPFI reduces fuel consumption by 31%. The most sophisticated versionof the MCE-5 VCRi planned for the near future could bring this reduction down to 45% while providing 16% more power and 62% more torque
MCE-5 VCRi also procures many other advantages that result ineven greater fuel efficiency, more comfort and driving pleasureand reduced vehicle costs:Remarkable combustion stability:MCE-5 VCRi combustion stability is exceptionally high. Itscoefficient of variation always remains under 3% (combustionspeed dispersion), which makes it possible to reduce its idlespeed to 550 rpm.With a high compression ratio and a limited FMEP (FrictionMean Effective Pressure) of roughly 0.55 bar, the hourly fuelconsumption of an idling MCE-5 VCRi is lower than 300g of fuel.This opens up many possibilities and, in particular, that of nothaving to use Stop & Start, which avoids stopping the heating orair conditioning in the passenger compartment and also avoidscooling the catalyst. At high torque, MCE-5 VCRi’s combustion stability leads toimproved vehicle NVH behavior, with increased driving pleasure. During the catalyst light-off phases (strategies to rapidlyincrease catalyst temperature), it’s possible to obtain moreexhaust enthalpy from the MCE-5 VCRi at the same level ofstability.It is therefore possible to either reduce the quantity of pollutantsemitted in the certification driving cycle or to reduce the cost ofthe catalyst.NVH & AFTER-TREATMENT:
