Development of the Hybrid Synergy Drive
Launched in 1997 the Toyota Hybrid System (THS) enabled a break from the traditional trade off between acceleration and fuel economy. Traditionally, more acceleration cost fuel economy but the Prius altered that paradigm, the Latin word itself meaning ‘ahead of its time’. An upgrade followed in 2003 with the development of the THS II system which has lead to the Hybrid Synergy Drive with which we are familiar today. The improvements in Hybrid design for the Toyota and therefore Lexus range are extensive and for the electric engine they include;
•  50% increase in motor output from 33kW to 50kW
• Greater efficiencies in hybrid transmission (i.e. the power splitting between petrol and electricity) increasing the voltage output from 274V to 500V.
• Enhancement of the electric engine through rotor strength- ening to permit an increase from 6,500 to 10,000 rpm
• Improvements in magnet configuration to an optimised V-shaped design.
From their own literature, the electric motor is reported to be more powerful than most 1.2 litre petrol engines. The development of the THS II system has provided at least a 5% improvement in vehicle efficiency on the earlier Prius hybrid. The end result is the world’s best fuel economy in a production vehicle that has so far sold 900,000 worldwide.
The ‘Hybrid Lexus Limousine’
We also had the opportunity to test out the new ‘Hybrid Lexus limousine’. This extended wheel base version of the LS 600h L is £88,000 of pure luxury. Equipped with rear seats more at home in a first class flight cabin; the rear passenger seats have a central cluster panel of several controls enabling the full range of movement and reclining of seats for comfort. Below the miniature fridge for champagne there was a concealed compartment which housed two remote controls which