Taking its name from the network of ancient trade routes which interweave across Central Asia, the 10,472-mile expedition saw three prototype Range Rover Hybrids, accompanied by four Russian-spec Discovery 4 support vehicles, tackling gruelling mountain terrain and extreme altitudes through some of the remotest and most beautiful regions of the Eurasian continent.
The team hit the road on August 22 and arrived ahead of schedule on Saturday, after 53 days travelling through 13 countries: England, France, Belgium, Germany, Poland, Ukraine, Russia, Kazakhstan, Uzbekistan, Kyrgyzstan, China (including Tibet), Nepal and finally India.
Potholed asphalt roads, hostile desert trails, rocky river crossings, and steep mountain passes tested their vehicles to the limits, causing the convoy to suffer 15 punctures, four damaged wheels and four cracked windscreens.
The expedition served as the final validation test for the Range Rover Hybrid before it is signed off for production. Data logging was focused on fine-tuning and calibration rather than durability, which had already been tested, and more than 300 gigabytes of live data on the vehicles’ performance was fed back to engineers in Gaydon via satellite uplink while the vehicles were underway.
Despite being crammed full of luggage, passengers, camping gear, food, roof racks, extra fuel and medical equipment (including a portable decompression chamber), the Silk Trail Range Rovers still returned 36-37mpg. The official combined figure is an impressively thrifty 44.1mpg.
In China the Land Rovers pioneered a crossing of the Xinjiang-Tibet highway, a route never before attempted by foreign-registered vehicles, which took the convoy up to altitudes of 17,648 feet (over 5300 metres). At these altitudes the oxygen content in the atmosphere drops to under half that at sea level, putting man and machine on the brink of failure. Here the hybrids’ combination of combustion engine and electric motor proved their worth, with the motors continuing to produce their maximum torque from 0rpm.
The hybrids employ a new prototype powertrain which couples Land Rover’s existing 3-litre SDV6 diesel engine with a 37kW electric motor, resulting in equivalent power and torque to the mighty SDV8 while generating only slightly greater emissions than the Td4 Freelander. Identical hybrid powertrains have been developed for both the Range Rover and Range Rover Sport for the 2014 model year.
Peter Richings, Jaguar Land Rover Hybrids and Electrification Director, commented: ‘In developing the hybrid-powered Range Rover, our objective was to gain hybrid’s fuel economy and carbon emissions advantages without compromising the Range Rover’s go-anywhere capabilities, its cabin space or its refinement. The success of this remarkable expedition clearly demonstrates we have achieved that.’