Renault, which held about 53% of the French LPG car market in 2001,has launched Laguna 1.6-litre 16V LPG models in both hatchback and Sport Tourer [estate car] forms.

In addition to an LPG injection system unique to Renault, the new Laguna derivative also introduces a new type of under-floor tank with useable capacity increased to 61 litres, about 50% more than existing automotive LPG tanks, with no reduction in luggage compartment volume.

Throughout 2001 and 2002, Renault has developed a new range of LPG vehicles in response to the introduction of the Euro 3/Euro 2000 exhaust emission regulations. This range consists of the Twingo 1.2 and 1.2 Van, Clio 1.2 and 1.2 Van, Kangoo and Express 1.2, Mégane Estate 1.6 16V and Scénic 1.6 16V.

Like the other engines in Renault’s LPG range, the Laguna 1.6-litre unit has a new gaseous injection system specially developed in collaboration with Sagem.

This new system is installed in exactly the same way as its equivalent in existing petrol engines: a multipoint (one injector per cylinder) gaseous injection system with sequential operation.

The LPG injection rail, in aluminium, is mounted on the inlet manifold. Each LPG injector is installed upstream of the inlet valve, alongside the petrol injector, and is equipped with a filter to prevent any blockage.

The LPG computer is connected to the petrol computer by a multiplexed CAN link. The company has devoted particular care to the operation and the exchange of information between the two computers.

The LPG computer is notably responsible for control of the gas injectors once the flow requirement and timing have been calculated, the measurement of gas temperature and the calculation of its pressure, the operation of the gauge and warning lights, and control of the main solenoid valve.

This LPG computer is in addition entirely ‘diagnosable’ within the Renault service network. For its part, the petrol computer calculates the gas flow and the timing. It controls the fuel selector relay and is responsible for inter-computer communication.

A major innovation of this system is that switching over to petrol is automatic should the LPG tank become empty.

These new vehicles comply with the Euro 3 (Euro 2000) emission regulations in both the petrol and LPG modes, and have the potential to achieve the Euro 4 (Euro 2005) requirements.

This new system is also equipped with E-OBD operative in the petrol mode, and is already equipped for E-OBD in the LPG mode when this is required by the regulations, from 2003 for new vehicles and from 2004 for all vehicles.

The Laguna 1.6 16V LPG is the first to use a new flat LPG tank installed beneath the rear floor. This provides a claimed record useable capacity of 61 litres to achieve an LPG-fuelled range of around 400 miles (600km). This new installation thus allows the capacity to be increased by almost 50% compared with a doughnut-shaped tank housed in the spare wheel well, while the capacity of the luggage compartment is unaffected.

Until now, gas-fuelled range has been criticised by buyers of LPG but, since this new installation does not reduce the size of the 70-litre petrol tank, the entire system gives a considerable range increase.

Renault has concentrated especially on the overall performance of the Laguna LPG tank through the use of stainless steel and the choice, with its industrial partner Portinox, of the hydroforming manufacturing process.

CO2 emissions of the Laguna 1.6 16V LPG are 13% lower than those of the equivalent petrol version.

LPG Lagunas cost 1,600 euros (£1,025; $US1,600), are built on-line at the Sandouville factory and sold in France with the same two-year warranty as the petrol and diesel versions.