Toyota has heralded an affordable compact hybrid car that will cut fuel use and emissions in half without resorting to expensive technologies or manufacturing methods.
Toyota’s FT-Bh Concept, which is having its world debut at the Geneva Motor Show, is about the same size as a Yaris but has shed well over 200kg to tip the scales at a miniscule 786kg.
The FT-Bh, which stands for Future Toyota B-segment hybrid, targets fuel economy of just 2.1 litres/100km and CO2 emissions of just 49 grams/km – almost twice as good as today’s hybrid flagship, Prius.
The ultra-light concept features exceptional aerodynamic quality, very low driving resistance and a highly efficient petrol-electric system – as well as exploring compressed natural gas (CNG) hybrid and plug-in hybrid powertrains that would produce even better efficiency.
Toyota Motor Europe president and CEO Didier Leroy said the FT-Bh shows what can be achieved when every aspect of the car is designed to reduce emissions.
“One year ago we challenged our engineers and designers to come up with a small super-efficient car at an affordable price, reinforcing our environmental leadership in the coming years.
“FT-Bh is the result: a full hybrid four-seater less than four metres long,” Mr Leroy said at the concept’s unveiling.
“It combines full hybrid efficiency, advanced aerodynamics and ultra-lightness – all achieved at a cost-level appropriate for a high-volume B-segment car.
“Having achieved such impressive results in a small car, we will be able to transfer the benefits to larger Toyotas.”
The design team, on a mission to achieve the best possible fuel economy and emissions, focused on five key areas: reducing weight, driving resistance (including aerodynamic and tyre performance), powertrain efficiency, thermal energy management, and electricity savings.
Toyota recognises that a real-world reduction of total global vehicle CO2 emissions is possible only if an affordable, ultra-low emissions vehicle can be manufactured and sold in sufficiently high volumes.
That made it important that the concept did not require exotic, expensive materials or complex manufacturing procedures, but used instead only those that are already commonly available in the motor industry.
“Ecomotion” was the theme for styling FT-Bh, with its shape demonstrating a new approach to bodywork design. Key panels, such as the roof, are formed to represent the way fabric can be stretched taut between fastening points, to reflect their ultra-light weight.
The front end of the car conveys Toyota’s design language with its large lower grille, together with a sculpted bonnet and headlamps that are integrated into the front wings. Ultra-slim roof pillars provide maximum visibility and a greater sense of space in the cabin.
The way in which the cabin merges seamlessly into the rear of the vehicle, with an uplifted rear bumper and chevron-shaped corner elements, helps achieve the best possible aerodynamic performance and deliver a drag coefficient of just 0.235.
The stretched fabric-look carries through to the minimalist interior, with a concave centre console creating a driver-focused cockpit, while maintaining the overall feeling of light and space.
The FT-Bh is 3985mm long, 1695mm wide and 1400mm tall with a 2570mm wheelbase.
Starting with the 1030kg kerb weight of a Yaris powered by a 1.0-litre, three-cylinder engine (not available in Australia), the concept car’s weight was trimmed to 786kg by using high-tensile steel, aluminium and magnesium.
As the hybrid powertrain is heavier than the petrol engine alone, the combined mass of the bodyshell, interior trim, chassis and electronics had to be reduced by around 340kg â€“ one third of the Yaris weight – to achieve the target.
Such a large saving in the weight of cabin parts has had a ripple effect in weight reduction in the rest of the vehicle.
For example, it means there is less load applied on the body structure and suspension, allowing components to be downsized – and less weight means a smaller displacement engine can be used, further saving weight and thermal energy losses.
FT-Bh’s full hybrid system – a masterpiece of downsizing with substantial weight savings in every driveline component – is almost 90kg lighter than the Hybrid Synergy Drive system in today’s Prius.
The lightweight two-cylinder, 1.0-litre Atkinson cycle petrol engine combines high efficiency with low thermal capacity. It benefits from detailed measures to increase combustion efficiency and reduce friction.
The car’s light weight makes it agile and responsive to throttle and brakes while the electric motor delivers maximum torque from standstill.
FT-Bh demonstrates the adaptability of Toyota’s Hybrid Synergy Drive technology by using two alternative powertrains: a CNG hybrid with 38 grams/km CO2 emissions and a plug-in hybrid emitting just 19 grams/km.
Lower Driving Resistance
Next-generation aerodynamic techniques include air intakes on the front extremities of the bodywork, air-stream alloy wheels, cameras instead of airflow-disrupting door mirrors and door latches in place of handles.
A pagoda-style roof with a dropped rear section, a sharply cut rear end that incorporates an air outlet slit and an under-floor spoiler contribute to smooth air flow.
The co-efficient of drag of just 0.235 compares with 0.25 for Prius and an average of about 0.29 for a B-segment car.
FT-Bh rides on 18-inch wheels fitted with narrow, large diameter 145/55 low-rolling resistance tyres.
Thermal Energy Management And Electricity Saving
Further goals for FT-Bh were improvements in the recovery of thermal energy and a 50 per cent reduction in electricity consumption. The cabin uses thermally efficient components and the air-conditioning focuses only on parts of the car where people are sitting.
The amount of electricity used by the LED headlamps, interior lighting and other electrical components has been drastically reduced, to the extent that power consumption is half that of conventional cars.
Glazing has been designed for maximum thermal efficiency and even the matte paint has been chosen for its excellent heat-insulation characteristics.