New Toyota Auris Hybrid on display at Geneva. Click to enlarge.

The 2.0 liter turbo diesel has been replaced by a new 1.6 liter D-4D unit, and the 1.4 liter D-4D engine has been substantially upgraded, offering best-in-class CO₂ emissions in the 90 hp category. A 1.8 liter hybrid powertrain completes one of the broadest ranges of engine choice for any model in this segment. Every engine in the range now meets Euro 6 emissions regulations.

The 2015 Auris range further benefits from suspension and steering revisions designed to improve ride comfort, handling and driver involvement. And numerous measures have also been introduced to reduce the transmission of Noise, Vibration and Harshness (NVH) into the cabin.

Toyota has also revised the Auris grade structure to bring Hybrid grades—Entry, Mid, Style and High—into line with the rest of the model range.

Lower full hybrid system emissions. The Hybrid model, with combined cycle fuel economy of 3.5 l/100 km (67 mpg US) currently accounts for more than 50% of all Auris sales in West Europe, a mix Toyota expects to grow further over the next few years. Since the hybrid powertrain was made available in the Auris range, more than 200,000 units have been sold. The Auris is the most sold hybrid in Europe.

The Auris full hybrid now returns CO₂ emissions figures as low as a 79 g/km in the European homologation combined cycle.

Capable of operating both independently and in combination, the HSD system’s 1.8 liter VVT-i gasoline engine and electric motor generate a maximum power output of 136 DIN hp (101 kW), equipping the Auris Hybrid with a 0-100 km/h acceleration time of 10.9 seconds and a maximum speed of 180 km/h (112 mph).

The Auris Hybrid can drive for up to 2 km (1.24 miles) at speeds of up to about 50 km/h (31 mph), depending on battery charge and driving conditions.

2015 Toyota 1.2T Engine. Click to enlarge.

1.2T: an all-new direct injection turbo gasoline engine. The all-new 1197cc, 16 valve, 4-cylinder, direct injection turbo gasoline engine offers a level of performance similar to the one of a 1.6 engine while its fuel consumption and CO₂ emissions are lower. The 1.2T belongs to the range of 14 new engines that Toyota will launch globally between April 2014 and the end of 2015. (Earlier post.)

The new 4-cylinder 1.2T engine is the second engine from this new family to come to Europe under the Toyota brand, after the 3-cylinder 1.0 engine that went on sale in AYGO and Yaris last year. (Earlier post.) Like the 1.0, the 1.2T uses advanced technologies that allow the engine to change from the Otto-cycle to the Atkinson cycle under low loads, vertical vortex high tumble air flow intake ports, an exhaust manifold integrated in the cylinder-head and advanced heat management.

To this, the 1.2T adds a direct injection system, as well as a water-cooled turbo and heat-exchanger. Furthermore, the VVT-i (Variable Valve Timing – intelligent) system known from the 1.0, is upgraded to a VVT-iW (Variable Valve Timing - intelligent Wide) system, which allows even more flexibility in the valve-timing.

The combination of these technologies results in increased performance and efficiency. For a displacement of 1197cc, the engine delivers 116 DIN hp (85 kW) and a constant torque of 185 N·m (136 lb-ft) between 1500 and 4000 rpm. It will push the New Auris, the first model to which it is applied, from 0 to 100 km/h in 10.1 seconds. 5^th gear acceleration from 80 to 120 km/h (50-75 mph) takes 13.7 seconds, and the top speed is set at 200 km/h (124 mpg). The car achieves 4.7 l/100 km (50 mpg) on the combined cycle, and delivers 109g/km of CO₂.

Avoiding knock. The key to achieving outstanding fuel consumption without compromising performance, is to apply a higher compression. But generally, as the compression increases, so does the risk of uncontrolled combustion (knocking).

The 1.2T’s high compression ratio of 10:1 was made possible with the adoption of a series of key technologies that improve control over the combustion process. That way, the risk of knocking could be avoided.

First, the intake ports have been designed to generate a more intense flow and a vertical vortex; the shape of the piston also has been optimized to improve in-cylinder turbulence. As a result, fuel and intake air mix faster, and a more homogeneous mixture is formed. This leads to a higher combustion speed, which helps prevent knocking.

Advanced heat-management is in itself a great way to improve fuel economy, but it is also another way of reducing the risk of knocking. The engine was designed in such a way that the temperature of each individual part can be optimized. For example, the bottom of the pistons is cooled by oil-jets and the cooling of the cylinder head is separated from that of the engine block. This allows to reduce the temperature in the combustion chamber, whilst keeping the block itself hot enough to reduce friction.

Direct injection contributes as well, as it helps to dissipate the heat in the combustion chamber. And the charge air passes through the intercooler, which uses an independent low temperature cooling circuit.

Low-end torque and quick response. A low-inertia turbocharger, the VVT-iW valve system and the D-4T direct injection system work hand in hand to ensure excellent torque delivery from the lowest engine speeds. Together with the limited volume intake system, this ensures an immediate response to the accelerator pedal.

The compact injection system has been newly developed for the 1.2T engine, and was targeted for utilization in a small displacement engine. It allows multiple injections per cycle, and the optimized width and reduced length of the fuel spray ensure the quality of the combustion, regardless of the engine regime and load.

From Otto to Atkinson. The VVT-i (Variable Valve Timing - intelligent) system operates on both the intake and the exhaust side, and allows maximizing torque at all engine speeds. In addition, the new VVT-iW (Variable Valve Timing - intelligent Wide) allows for the intake valve closing to be delayed—meaning that the engine can operate in both the Otto and the Atkinson cycle.

The latter is used in extremely low load conditions, when the intake valve remains open for a fraction of time, after the compression stroke has set in, allowing part of the gas charge to be pushed back into the intake. As a result, the effective compression stroke is shortened. Pumping losses are reduced, since the pressure on the piston is lower, and also the throttle valve can be opened wider.

Quick and smooth Stop & Start. A new start control was developed to ensure a quick and smooth engine restart. When the system shuts down the engine, it controls the stop position to leave the piston half way in the compression stroke. Then, upon restart, it applies stratified injection in the first compressed cylinder to counter vibrations. And by retarding the ignition, torque increase is kept in check, preventing the engine from revving excessively, hence ensuring a confident and tranquil take-off.

New 1.6l D-4D. Making its first appearance in the Auris range, a new 1598 cc turbodiesel replaces the outgoing 2.0l unit. The new engine develops 112 DIN hp (84 kW) and maximum torque of 270 N·m (199 lb-ft) between 1750 and 2250 rpm. This equips the Auris 1.6 D-4D with performance figures of 0-100 km/h in 10.5 seconds, 80-120 km/h (50-75 mph) (in 5^th gear) in 10.9 seconds, and a top speed of 190 km/h (118 mph).

Conversely, CO₂ emissions are markedly lower than those of the outgoing 2.0 liter unit, falling to 104 g/km, and average fuel consumption is now only 4.1 l/100 km (57 mpg US). Auris 1.6 D-4D cost of ownership is further reduced by a new service scheme featuring a 20,000 km (12,427 miles) service interval.

Uprated 1.4l D-4D. The 1364 cc turbodiesel has been upgraded to be Euro 6 compliant, but the changes go significantly further than that. The unit features numerous enhancements to both improve performance and lower emissions. A new turbocharger reduces friction in the turbine shaft by 20%, and improves efficiency to generate a higher boost pressure at low engine speeds.

A new Solenoid fuel injection system features a larger supply pump and higher common rail injection pressures of 180 Mpa, making it compatible with the Euro 6 engine’s ECU and software. A NO_x Storage Reduction (NSR) catalyst has been adopted within the exhaust system to meet the Euro 6 requirement for a 55% reduction in NO_x.

A new piston design with an open chamber combustion bowl improves fuel economy by 3.4%. The new pistons feature a Diamond-like Carbon (DLC) coating which reduces friction to lower fuel consumption.

A new cylinder head cover is now fabricated in plastic for a 40% reduction in weight, and offers improvements to both camshaft lubrication and oil capture performance.

The uprated engine develops 66 kW / 90 DIN hp. The breadth of torque generation has been expanded 400 rpm lower down the rev range, with a maximum 205 N·m (151 lb-ft) now available from only 1,400 rpm, up to 2,800 rpm. The Auris 1.4D-4D will accelerate from 0-100 km/h in 12.5 seconds, and has a maximum speed of 180 km/h (112 mph).

Equipped with a manual transmission and Stop & Start technology, the improved 1.4 D-4D 90 unit now returns a combined cycle fuel consumption of 3.4 l/100 km (69 mpg US) and benefits from a substantial reduction in CO₂ emissions to 89 g/km.

Multidrive S Continuously-Variable Transmission. Available on 1.2 turbo and 1.6 Valvematic gasoline versions of the Auris, Multidrive S is a continuously-variable transmission (CVT) with a fully automatic seamless shift mode or a sequential, stepped 7-speed Sport mode.

In Sport mode, the system is optimized for response and direct engine control, and the transmission step position can be selected by the gear lever, or by shift paddle. Sport mode also features precise cornering control. On detecting deceleration, the system downshifts and applies engine braking to assist the braking force. On corner exit, predictive downshift logic controls the system to ensure the optimal gear ratio is selected for the required level of acceleration.

Improved driving dynamics and NVH. The new, Auris range benefits from further suspension and steering revisions designed to improve ride comfort and handling. Numerous measures have also been introduced to reduce the transmission of Noise, Vibration and Harshness (NVH) into the cabin.

Components of the front MacPherson strut suspension have been revised, including the design of the coil spring, shock absorber, upper insulator, bound stopper and stabiliser bush.

The new, Auris features either a double wishbone or torsion beam rear suspension system. The double wishbone system equips all 1.2 liter turbo, 1.6 liter gasoline, 1.6 liter diesel and full hybrid models. 1.33 liter gasoline and 1.4 liter diesel engine models feature torsion beam rear suspension.

In combination, these front and rear suspension revisions improve initial roll damping, minimise friction and enhanced straight-line ride comfort.

In addition, the mapping of the Auris’ Electric Power Steering (EPS) has been tuned to further build steering weigh as vehicle speeds rise, giving improved feedback above speeds of 60-80 km/h (37-50 mph).