Key to the successful installation of Hybrid Synergy Drive series/parallel full hybrid system within the Auris front-engined platform is the housing of the electric motor, generator and power split device in one transmission casing the size of a conventional gearbox. The full hybrid drive system’s electric continuously variable transmission is controlled by shift-by-wire technology, using an electric shift lever system.

System power is provided by a lightweight, compact, 4-cylinder, 1798 cc, Atkinson cycle VVT-i gasoline engine developing 98 DIN hp (73 kW) at 5200 rpm and 142 N·m (105 lb-ft) of torque at 4000 rpm, and a high performance, permanent magnet, synchronous 60 kW electric motor generating a maximum 207 N·m (153 lb-ft) of torque from 0-13,000 rpm. Combined cycle fuel consumption is calculated to be 3.8 L/100km (62 mpg US), with CO₂ emissions of 89 g/km.

Powered by the NiMH battery, the electric motor works in tandem with the gasoline engine to boost acceleration during normal driving. The electric motor alone powers the driven wheels when the Auris HSD is operating in EV mode. During deceleration and under braking, the electric motor acts as a high-output generator to effect regenerative braking.

In combination, the 1.8 liter VVT-i gasoline engine and electric motor generate a maximum system power output of 136 DIN hp (101 kW), offering performance to match a conventional 2.0 liter diesel or gasoline hatchback. Targeted acceleration from 0-100 km/h is 11.4 seconds. In addition, the Auris HSD generates significantly lower NO_x emissions than diesel engined cars of comparable performance, Toyota points out.

The Auris HSD offers four driving modes, including three on-demand modes: an EV mode for up to 2 km at speeds of up to about 50 km/h ; an ECO mode maximizing hybrid system efficiency and fuel economy; and a POWER mode boosts system performance. In addition, an Eco Drive Monitor helps drivers maximize the fuel efficiency of Toyota’s Hybrid Synergy Drive system.

HSD-specific design modifications have reduced the Toyota hybrid’s coefficient of drag from Cd 0.290 to 0.283, effecting reductions in both fuel consumption and CO₂ emissions.

Optimal Drive. As a result of Toyota Optimal Drive technology, the Auris will be the first Toyota to comply with Euro 5 emission standards across the entire European model range by July 2010.

Toyota Optimal Drive focuses on several key aspects of powertrain development such as environmentally friendly technologies, low friction components, lightweight, compact design and enhanced combustion efficiency.

The application of Toyota Optimal Drive across the Auris range has significantly reduced CO₂ emissions. The overall Auris CO₂ average has been reduced from 152 g/km in 2007 to 142 g/km in 2009. In 2011, which will be the first full year of Auris range sales, the figure will reduce further to just 125 g/km.

The 1.33 L Dual VVT-i engine. Click to enlarge.

Gasoline engines. The 1.33 liter Dual VVT-i gasoline engine generates 73 kW/ 99 DIN hp and maximum torque of 128 N·m (94 lb-ft) at 3,800 rpm, while returning an average fuel consumption of 6.0 L/100 km (39 mpg US) and CO₂ emissions of 139 g/km.

The unit benefits from numerous Toyota Optimal Drive engine optimizations. A combination of lightweight technology, a resin cylinder head cover and intake manifold, and a compact design has effected a substantial reduction in engine weight and size. Combustion efficiency has been improved through the use of a high efficiency intake port, a high compression ratio and long reach spark plugs. Extensive friction reduction measures include enhanced engine block rigidity and bore circularity, an improved valve roller rocker arm design with a new camshaft profile, small, lightweight pistons with a low friction coating, low viscosity oil and a water jacket spacer.

Toyota Optimal Drive’s environmental technologies are represented by the application of a wide ratio 6-speed manual transmission and optional, Stop & Start System technology. A permanently engaged ring gear mechanism allows for automatic engine restart within half a second when the clutch is lifted, with significant reductions in engine start noise and seat vibration levels.

Thus equipped, the 1.33 litre Dual VVT-i unit&’s fuel consumption and CO₂ emissions are lowered still further to 5.9 L/100 km (40 mpg US) and 136 g/km respectively.

The 1.6-liter Valvematic gasoline engine develops 132 DIN hp and maximum torque of 160 N·m (118 lb-ft) at 4400 rpm. When equipped with a 6-speed manual transmission, the unit returns a combined cycle fuel consumption of 6.6 L/100 km (36 mpg US) and generates CO₂ emissions of 152 g/km. MultiMode transmission further reduces both fuel consumption and emissions, to 6.3 L/100 km (37 mpg US) and 146 g/km respectively.

Valvematic is a further development of Toyota’s Dual Variable Valve Timing-intelligent (Dual VVT-i) system. Adding lift and duration control to the variable inlet valve timing to deliver more power for less fuel consumption with reduced CO₂ emissions, Valvematic also reduces friction and pumping losses under light engine loads, further lowering fuel consumption.

The 1.8 liter Valvematic engine develops 147 DIN hp and maximum torque of 180 N·m (133 lb-ft) at 4000 rpm, with combined fuel consumption of 6.7 L/100 km (35 mpg US), and CO₂ emissions of 155 g/km.

Through the application of Toyota Optimal Drive, both engines benefit from the same lightweight technology, compact design and combustion efficiency engine optimizations as the 1.33-liter unit.

In addition, friction reduction measures include an improved valve roller rocker arm design with a new camshaft profile, small, lightweight pistons with a low friction coating, enhanced engine block rigidity and bore circularity, and low viscosity oil.

The environmental technologies of Toyota Optimal Drive are represented by the application of wide ratio 6-speed manual transmissions and an optional, MultiMode transmission available with the 1.6-liter unit.

Diesels. The three diesel engines in the Auris 2010 model range also benefit from the application of Toyota Optimal Drive technologies. Lightweight technology and a compact design have resulted in a marked reduction in engine weight and size. Numerous combustion efficiency enhancing measures include a lower compression ratio, optimized combustion chamber dimensions, enhanced Exhaust Gas Recirculation (EGR) cooler efficiency and stainless steel exhaust manifolds with close-coupled Diesel Particulate Filters (DPF).

The adoption of Piezo injectors makes multi-phase high speed injection possible. This has the effect of both lowering the rate of combustion expansion and effecting a more thorough burn within the combustion chamber, thus further reducing particulate, NO_x and CO₂ emissions.

The 2.2 liter engine also benefits from Toyota’s Diesel-Clean Advanced Technology (Toyota D-CAT), which incorporates a Diesel Particulate and NO_x Reduction filter (DPNR).

The 1.4 liter D-4D engine develops 90 DIN hp and maximum torque of 205 N·m (151 lb-ft) at 1800 to 2800 rpm, and may be equipped with a Diesel Particulate Filter (DPF) for CO₂ emissions that are amongst the lowest in the C-segment. Manual versions fitted with a DPF return 4.5 L/100 km (52 mpg US) and a 118 g CO₂/km.

This emissions performance has been achieved through combining Toyota Optimal Drive with various measures designed to maximize the aerodynamic and fuel efficiency of the Auris 1.4 D-4D 90, such as lowered suspension and low rolling resistance tires.

With a DPF fitted as standard, the 2.0 D-4D 125 delivers 126 DIN hp and maximum torque of 310 N·m (229 lb-ft) from 1800 to 2400 rpm. Combined cycle fuel consumption is 5.2 L/100 km (45 mpg US) and CO₂ emissions are 138 g/km.

The 2.2 liter turbodiesel further benefits from Toyota’s Diesel-Clean Advanced Technology (Toyota D-CAT), which incorporates a Diesel Particulate and NO_x Reduction filter (DPNR).

The 2.2 D-4D 180 unit delivers 177 DIN hp and maximum torque of 400 N·m (295 lb-ft) between 2000 and 2800 rpm. Average fuel consumption is 5.9 L/100 km (40 mpg US), and CO₂ emissions are 154 g/km.

6-speed manual and MultiMode transmissions. Every engine in the Auris 2010 range is mated to a Toyota Optimal Drive six-speed manual transmission featuring wide-spread ratios designed to optimize fuel consumption and lower CO₂.

An optional, MultiMode transmission is available on 1.6 Valvematic gasoline and 1.4 D-4D 90 diesel versions. MultiMode is an automated manual transmission with a fully automatic shift mode and no clutch pedal. It offers the driver a choice of two, fully automatic gear change modes or a manual, sequential gear change with steering wheel-mounted shift paddles.