New Jaguar and Land Rover hybrid models will go on sale in the UK within five years. Engineers are experimenting with a range of technologies based around two new engines a 3.0-litre version of today's 2.7-litre V6 diesel and the all-new direct-injection 5.0-litre V8, to be launched late next year.A micro-hybrid using stop-start technology and based around the 3.0-litre V6 diesel will be the first to be launched in the Land Rover Discovery 3, Range Rover Sport, Jaguar XF and Jaguar XJ in 2010.On its own it could boost the fuel economy of the four vehicles by up to 10 per cent.The diesel is the engineering priority because it makes up the bulk of JLR sales in Europe. Land Rover is understood to also be engineering a 'mild-hybrid' version with a super-capacitor for short-term storage of electricity and a starter-generator capable of recharging the battery during engine-braking. This could also appear as early as 2010.An eight-speed ZF gearbox is key to this development. It features a completely new approach to the internal design of an auto, itself a fuel-saving feature, and a separate hydraulic reservoir that makes the 'box compatible with stop-start devices unlike today's six-speed ZF unit.Jaguar Land Rover is also looking at the technology that will be used in Mercedes' S-Class hybrid. It uses ZF's Dynastart electric motor to replace the torque convertor. It can be engineered for either either mild hybrid operation, in which the electric motor acts as a torque booster, or full-hybrid operation in which the electric motor can power the car alone.Jaguar is considering the system for a full-hybrid version of the next XJ and it could be on the market as soon as 2012. Land Rover is looking at a different hybrid solution using its rear-mounted'Electric Rear Axle Drive' electric motor.Longer-term JLR plans to develop green technologies have won government financial backing under the Low Carbon Vehicle programme. These are likely to result in production developments over the next five to 15 years and include the REHEV (Range Extended Electric Vehicle) for aplug-in hybrid, a new flywheel-based energy recovery system, and a 120g/km luxuryJaguar, the so-called 'Limo-Green' project using full-hybrid technology. Independant firm, Liberty, has recently unveiled plans to build an electric Range Rover. Read about it here.