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By Richard Aucock

Renault is replacing its normally aspirated 2-litre gasoline engine with a 1.4-litre downsized Nissan unit. The approach saves fuel and makes production more economical too.

The resulting 1397cc “TCE 130” powertrain will go into the Megane III, due out later this year. It produces the same 190Nm of torque and 96kW (130hp) of power as the 2-litre unit, but CO2 emissions are 16 per cent lower: 160g/km, instead of 191g/km. Fuel economy figures are not yet available.

The main cost of developing a new engine is the block. By using Nissan’s all-alloy unit and avoiding direct injection technology, Renault saves money. The turbo used is also inexpensive – a low-inertia single-scroll unit.

Project engineer Stephane Guilan said: “Twin scroll units theoretically have more performance, but this would be so small, it wouldn’t be efficient. Here, we’ve managed to replicate a normally aspirated feeling.”

Renault instead focused on detailed refinements of the engine. Inlet ports create a tumble effect, mixing fuel and air more evenly. Combustion is quicker and low-end torque is higher as a result, said Guilan, important for economy and in getting customers to accept a reduction in swept volume.

The engine also has variable intake valve timing to improve torque. And Renault will match it to a six-speed gearbox with a tall top ratio.

Sodium-filled exhaust valves help manage the high exhaust gas temperatures associated with a small turbo engine. The sodium’s fast absorption of heat can help prevent the hot-spots that cause pre-ignition.

Renault has fitted a chain-driven cam. “Everything is packed so tightly on the engine that removing ancillaries to meet scheduled belt changes would give unacceptable service times,” said Guilan. “Making it maintenance-free made more sense.”

The engine is manufactured in Valladolid, Spain and is likely to go into other Renault models in future.