Prius Plug-in Hybrid 2012 DPL: Plug-in hybrid powertrain based on HSD technology

​Settinga new benchmark in environmentally-friendly mobility, the new Prius Plug-inHybrid represents a new implementation of the Hybrid Synergy Drive^®system's capabilities. 

Buildingon the core technology of Toyota's renowned full hybrid powertrain, the PriusPlug-in Hybrid addresses the specific needs of urban-based customers with asignificantly extended, fully-electric EV driving range of 25 km for shorter,cross-city journeys, while the hybrid powertrain's petrol engine awards the newToyota PHEV true long range capability of over 1,200 km.

Afull hybrid capable of operating in petrol and electric modes alone, as well asa combination of both, the Prius Plug-in Hybrid delivers impressive, seamlessacceleration and remarkably quiet operation, while returning unparalleled fuelefficiency and the lowest possible emissions. 

Thenew Toyota PHEV automatically operates in full hybrid mode once the extended EVrange has been expended. This removes the range anxiety which has come totypify the driving of fully electric vehicles. Moreover, the uniquecharacteristics of Toyota's full hybrid powertrain require no change in drivingstyle or behaviour.

Performance— unparalleled fuel efficiency and emissions

TheHybrid Synergy Drive^® powertrain generates a total system poweroutput of 136 DIN hp and allows the Prius Plug-in Hybrid to accelerateseamlessly from 0-100 km/h in 11.4 seconds, and on to a top speed of 180 km/h. 

Conversely,with the new Toyota PHEV's overall fuel efficiency significantly enhanced byits extended EV range, the Prius Plug-in Hybrid returns a remarkably low fuelconsumption figure of only 2.1 l/100 km in the European homologation combinedcycle — an increase in fuel efficiency of over 45% compared to theregular Prius. 

Commensurately,CO₂ emissions have also fallen to just 49 g/km. In addition, the newPHEV generates significantly lower NO_X and particulate emissionsthan diesel engined cars of comparable performance. 

Moreover,when operating in its extended EV mode, the Prius Plug-in Hybrid generates zeroCO₂, NO_X and particulate emissions, driving withcity-crossing capability for up to 25 kilometres at speeds of up to 85 km/h,dependant on battery charge and driving conditions. 

Thoughits extended EV range plays a significant part in lowering the new ToyotaPHEV's combined cycle fuel economy and emissions, the Prius Plug-in Hybridremains remarkably efficient when operating purely in full hybrid drive mode. 

Afterthe EV range has been expended, the HSD system still returns fuel consumptionof only 3.7 l/100 km, and generates class-leading CO₂ emissions ofjust 85 g/km. These figures are even lower than that of regular Prius, mainlydue to the vehicle's new Lithium-ion battery, which can more efficientlyrecover energy under braking, recharging the battery more quickly and allowingowners to drive more often in EV mode. 

Inaddition, the Prius Plug-in Hybrid has been fitted with the latest generationof low rolling resistance tyres. 

Thanksto its highly efficient HSD powertrain, the Prius Plug-in Hybrid'senvironmental performance in hybrid mode is superior to rival plug-ins inrange-extender mode.

HybridSynergy Drive^® — PHEV system architecture

Thenew Toyota PHEV's series/parallel full hybrid system features a 1.8 litre VVT-i petrol engine, a powerful electricmotor, a generator, a high performance Lithium-ion battery and a power controlunit. A power split device employs a planetary gear set to combine andre-allocate power from the engine, electric motor and generator according tooperational requirements. 

Keyto the successful installation of Hybrid Synergy Drive^® within thePrius Plug-in Hybrid's front-engined platform, the electric motor, generatorand power split device are all housed in one transmission casing the size of aconventional gearbox. 

Unlikea conventional, belt-driven CVT transmission, HSD delivers driving torquethrough a power split device in the form of planetary gear set. The generatoris connected to the sun gear. The engine is connected to the planetary piniongear carrier. And the electric motor is connected to the outer, ring gear,itself directly connected to the differential, which drives the wheels. Hence,with power transmitted to it either from the engine, the electric motor, or acombination of the two, the rotational speed of the ring gear determines thespeed of the vehicle.

Systempower is provided by a lightweight, highly compact, 4-cylinder, 1,798 cc, Atkinson cycle VVT-i petrol enginedeveloping 99 DIN hp/73 kW at 5,200 rpm and 142 Nm of torque at 4,000 rpm, anda high performance, permanent magnet, synchronous 60 kW electric motorgenerating instant power from 0 rpm and a maximum 207 Nm of torque. The petrolengine and electric motor combine to give a total system power output of 136 DIN hp/100 kW.

Poweredby the hybrid Lithium-ion battery, the electric motor works in tandem with thepetrol engine to boost acceleration during normal driving. Power allocation isconstantly adjusted between engine and electric motor to combine optimumperformance with maximum fuel efficiency. 

Theelectric motor alone powers the driven wheels when the Prius Plug-in Hybrid is operating in expanded EV mode. AnEV range of up to 25 km is dictated by battery charge and driving conditions.However, once the EV battery charge has been exhausted, the Toyota PHEVautomatically operates as a full hybrid until recharged from an external powersupply, thus eradicating the limited range constraints of a conventionalelectric vehicle.

Maximisingthe Hybrid Synergy Drive^® system's efficiency, and regardless of thedriving mode selected, the electric motor also acts as a high-output generatorduring deceleration and under braking, to effect regenerative braking. Normallywasted as heat, kinetic energy is recovered as electrical energy for storage inthe high performance Lithium-ion battery.

NewCompact, Lightweight and High-capacity Lithium-ion battery

Fundamentalto the successful commercial application of PHEV technology, the Prius Plug-inHybrid features a newly developed Lithium-ion battery pack.

Lithium-ionbatteries have been selected because they have ideal characteristics for use ina PHEV. They have a superior volume energy density and are very compact,offering a larger EV driving range with little adverse weight or packagingissues. They can be recharged quickly and can effectively recover energy underbraking, improving HSD system efficiency.

Asa result of Toyota's and its partners' continuous effort for improvement , thePrius Plug-in Hybrid's Lithium-ion battery pack has a 4.4 kWh capacity -almostfour times that of the latest generation Prius- and its SOC (State of Charge)for use has been enhanced to approximately 60%.To manage the increase involtage output of the new battery, the Hybrid Synergy Drive® system's revisedPower Control Unit (PCU) features a new voltage boost converter with evengreater durability.

Despitethis increase in power output, significant changes to the 288 cell battery packused in prototype versions of the Prius Plug-in Hybrid have allowed for the newLithium-ion pack's installation with no impact on rear passenger seataccommodation or luggage space, which are now almost identical to that of thestandard Prius.

Thecapacity of each battery cell has been enlarged four-fold over those of theprototype vehicles, and the new battery is now a 56 cell, one pack structurecomprising a stack of four, 14 cell, series-connected batteries. 

Inconjunction with the adoption of a new aluminium frame structure, theserevisions have reduced the volume of the battery pack from 201.7 to just 87.2 litres and halved its weight from 160 to only 80kg. As a result, the Prius Plug-in Hybrid weighs only 55 kg more than astandard Prius.

Rapid,Convenient Battery Recharging System

Viaa battery charger inlet conveniently located beneath a discreet, flush-mountedpanel in the opposite rear wing to the Toyota PHEV's fuel filler cap, thebattery pack can be fully recharged in 1.5 hours from a standard, 230V householdoutlet. 

Operatingwith a charging efficiency of some 84% when allied to a 230V power source, thebattery charger itself is positioned under the hybrid battery, converting ACelectricity to DC current to charge the Lithium-ion battery pack.

Severalimprovements have been made to the robust, highly efficient charging systemfitted to the prototype versions of the Prius Plug-in Hybrid. And a batterycharger timer function has been added, allowing users to set both the start andend time of battery charging.

ACCID (Charging Circuit Interrupter Device) is installed inside the batterycharger cable to automatically block the supply of AC current in the case ofelectrical leakage during charging. The CCID main body size has been reducedcompared to that of the prototype vehicle, and the power plug can now beremoved and replaced to enhance usability.

Batterycharger cable flexibility has been improved for easier handling during coldweather, and users can choose between a cable length of 5 or 10 meters. A rangeof replaceable power plugs is available for compatibility with the diverseoutlet shapes of various countries and regions. And a new cable has beendeveloped for compatibility with the Mennekes-type charging station expected torepresent the mainstream charging infrastructure in Europe. The cable is storedin a dedicated compartment under the loadspace floor.

Thebattery charger connector has also been modified from the prototype model toimprove ease of use. Finished in blue, the main body of the connector now has ascratch resistant surface finish. A freeze-proof lock release button shape hasbeen adopted, and the button has been chrome-plated to suppress corrosion. Apadlock-type cable lock may now also be fitted to the lock release button forimproved security.

Thebattery charger inlet itself has also been revised to improve operability. Theinner and outer lids of the inlet have been integrated to simplify the openingand connection process. An LED lamp fitted inside the lid illuminates thecharger inlet connector, and a battery charger lamp beside the connectorindicates battery charging status.