ES3 - Toyota's Concept Of The Near Future - A Highly Efficient Powertrain | Part Two

Highly Efficient Powertrain
  • 1.4-litre common rail diesel
  • Continuously variable transmission (CVT)
  • Stop &

    Go powertrain management

  • Regenerative braking system
The key to ES3’s outstanding fuel economy is a highly efficient powertrain combined with a light and aerodynamic body. An advanced diesel engine is combined with a Continuously Variable Transmission (CVT) to maximise engine efficiency – and some potential waste energy is recovered using technology developed for the Toyota Hybrid System.

The ES3 uses a 1.4-litre, direct injection, turbo diesel with intercooler which produces high output, low vibration and low noise. Precise fuel control is provided by the high pressure, common-rail injection system and reduced friction and a variable geometry turbocharger contribute to high fuel efficiency and increased performance.

In addition to the common-rail fuel injection, the engine also uses Exhaust Gas Recirculation (EGR) and Toyota’s new Diesel Particle Nitrous-Oxide Reduction (DPNR) technology to further clean exhaust emissions (fuel containing less than 10ppm of sulphur should be always used with DPNR). As a result ES3’s emissions match those needed to meet Euro Step IV for petrol-powered vehicles and are well below diesel equivalents.

The newly developed, belt type CVT is fitted with a torque converter which locks up from low speeds, thereby further improving fuel efficiency. Potential noise levels are suppressed through the use of a torsional damper integrated in the torque converter.

Two key technologies from the Toyota Hybrid System provide further energy conservation. A Stop & Go powertrain management system turns the engine off when the vehicle is stationary in traffic and provides instant restart.

Regenerative braking helps recapture energy otherwise wasted during braking. The electrical energy is stored in a 42v capacitor and can be used to operate the starter or, through a converter, to recharge the battery. This also reduces the workload for the alternator, further increasing fuel efficiency.

Light, Aerodynamic Body
  • Aluminium body and plastic panels
  • Reduced weight components and seats
  • Drag coefficient 0.23
The kerb weight of just 700kg is achieved through the use of a strong, but light, aluminium body with plastic outer panels. These plastic panels include the bumpers, side panels of the front and rear fenders, rear window surround, radiator support, fuel tank and rear boot floor.

Further weight reduction is achieved by intelligent design of interior components, such as the instrument panel and heater modules. Front seat frames are made of magnesium alloy and seat cushion weight has been reduced.

Weight has been taken out of a wide range of components including items such as brake callipers, suspension parts, brakes and wheels – leading to a 65kg (or roughly 40%) reduction in chassis component weight over a conventional structure.

ES3 is extremely aerodynamic with a drag coefficient of 0.23, despite the overall length of only 3.52m. This is achieved by optimisation of the rear body shape, increasing the floor height to allow smooth airflow under the car and tilting up the rear end of the floor. Further measures include optimised air-intake design, smooth wheel covers and bracket type door mirrors.

continues... | Part Three
Published 22 November 2002 Melanie Carter

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