New models - Toyota - Aurion
Aurion: The drivetrain
A Lexus V6, combined with a six-speed auto, gives Aurion the edge over its rivals
18 Oct 2006
POWER is one thing. But the Aurion’s Japan-sourced 200kW/336Nm 3.5-litre quad-cam 24-valve V6 is also being billed as the most advanced engine Toyota has offered yet in an Australian-built car.
Codenamed 2GR-FE, and essentially the same engine found in the 203kW/342Nm Lexus RX350, the V6 has dual variable valve timing "with intelligence" (VVT-i), which is claimed to be responsible for improved performance – in particular boosting torque at low-medium and high rpm – and reduced fuel consumption and emissions.
According to the manufacturer, dual VVT-i can alter inlet timing across a range of 40 degrees (relative to crankshaft angle) and alter exhaust valve timing across a range of 35 degrees. The result is optimisation of the valve overlap period relative to the engine and driving conditions, with the amount of valve overlap ranging from one degree to 76 degrees (again, relative to crankshaft angle).
Other engine features include roller rockers (with maintenance-free valve clearance adjusters), direct ignition, electronic control for the "acoustic control induction system" (ACIS) and a lightweight cast-aluminium cylinder block. Service weight is 163kg.
The 3456cc 60-degree V6 has an oversquare bore-and-stroke relationship of 94mm x 83mm. Compression ration is 10.8:1.
The 200kW maximum power peaks at 6200rpm, while the 336Nm maximum torque is produced at 4700rpm. Power rises to 204kW on premium unleaded, while fuel consumption rating sits at 9.9L/100km when using premium-unleaded petrol, as per the ADR 81/01 standard. No consumption figure is given for regular unleaded.
Kerb weight is listed at 1590kg for the AT-X variant, with all models claimed to reach 100km/h from standstill in 7.4 seconds.
The engine meets Euro IV emissions standards, which is one rung above the Euro III minimum required under ADR 78/01. To achieve Euro IV, carbon monoxide emissions (CO) levels must be reduced from 2.3g/km to 1.0g/km, hydrocarbon (HC) emissions reduced from 0.2g/km to 0.1g/km and nitrogen (NOx) emissions reduced from 0.15g/km to 0.8g/km.
CODENAMED U660E, the Toyota-designed and built six-speed automatic transmission fitted as standard to Aurion has what Toyota calls "artificial intelligence" – an elaborate term to describe the adaptive shift pattern that alters in accordance with factors such as throttle opening angle, accelerator pedal operation and vehicle and engine speed.
The U660E’s design includes two planetary gear sets, creating a six-speed gearbox with a shorter shaft length and smaller exterior dimensions than a five-speed unit.
It uses an "ultra flat" torque converter to reduce transmission length (by around 12mm) and weight. The ultra-flat torque converter also has a low-speed lock-up damper for smooth low-speed lock-up.
Both fifth and sixth ratios are over-driven, with gear ratios as follows: first – 3.300 second – 1.900 third – 1.420 fourth – 1.000 fifth – 0.713 sixth – 0.608 and reverse – 4.148. Final drive is 3.685:1.
Toyota says a manual transmission was never in the Aurion plan – even for Sportivo variants – because manual versions account for less than five per cent of Camry Sportivo variants.
Toyota also claims it is made redundant by the manual-shift mode in Toyota’s new in-house 6-AT, which is lighter and more compact than its Avalon forebear’s five-speed auto.
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