Range Rover diesel hybrids on Silk Trail

The all-new L405 Range Rover launched internationally 12 months ago but now the family is set to grow with the introduction of a diesel-hybrid version.

We had a brief preview of the Range Rover hybrid vehicle, but a 5-10km drive is hardly enough to form any meaningful conclusions about Land Rover’s first ever production hybrid.

The British company's development team covered a bit more than that as the three prototypes completed the Silk Trail, clocking up 16,850km. The trek started from Solihull, the home of Land Rover, and ended in Mumbai, home of Jaguar Land Rover’s owners, Tata.

According to Land Rover, the Range Rover’s hybrid engine combination – with a 35kW electric motor supporting the TDV6 3.0 litre turbo-diesel engine – returned fuel consumption of around 7.8L/100km over the journey.

The journey took 53 days, covered 13 countries and two continents, effectively putting the Range Rover Hybrid prototypes through their final extreme engineering sign-off test.

The vehicles were subjected to ambient temperatures from -10 degrees to 43 degrees, climbing to altitudes of 5500 metres across virtually every type of terrain.

The Range Rover’s all-terrain prowess was put through the wringer, as hostile conditions on the route included asphalt roads riddled with vast and deep potholes, dusty desert trails, and numerous miles of mud and gravel tracks, not to mention cattle trails.

In addition, river crossings, treacherous mountainous passes partly blocked by rock falls, the thin air of extremely high altitudes and the dense and erratic traffic of Chinese and Indian roads all added to the test of man and machine.

The Rangie prototypes were also the first foreign-registered cars to drive China’s Xinjiang-Tibet highway.

From Land Rover’s Solihull base, the test fleet blazed a trail through France, Belgium, Germany, Poland, Ukraine, Russia, Kazakhstan, Uzbekistan, Kyrgyzstan, China (including Tibet), Nepal and India.

Seven consecutive days were spent at altitudes between 3350 and 5379 metres, where the  oxygen content in the air is reduced from the 21 percent found at sea-level to as little as 10 percent, making movement more difficult for humans and internal combustion engines.

The Range Rover convoy was equal to the conditions, benefitting from the electric motor’s instant torque at zero revs per minute (rpm), despite being laden with heavy loads including luggage, camping gear, food, medical equipment, and aerodynamically-unfriendly roof-racks carrying spare wheels, tyres and jerry cans of fuel.

Land Rover development engineers closely monitored data loggers fitted to each car, sending back more than 300 gigabytes of detailed technical records to their engineering team at Gaydon in the UK.

The purpose of the expedition was not to test the reliability of mechanical components, which Land Rover says are already proven, but to fine-tune the calibration of engine and transmission software to ensure seamless performance in all terrains and extreme temperatures and altitudes.

Technical setbacks reflected the roughness of the road surfaces; casualties included 15 punctures among the expedition’s three Range Rover Hybrids and four support vehicles, four wheels damaged by deep potholes, and four windscreens cracked by stones thrown-up on loose surfaces.

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