Two new super-frugal internal combustion engines have been detailed by Renault, including a 0.9-litre TCe turbocharged petrol.

The second is a 1.5-litre diesel, and both engines will 89bhp. The diesel is adapted from the 108bhp version of the same unit seen in Frankfurt last year, but the petrol is new.

Using the lowest-inertia turbo on the market (that means small), the small-capacity engine manages to combine high economy with enough punch when required. It will be launched in the next Clio and will eventually replace the existing 1.0-litre TCe.

The advancements have been made as a result of downsizing expertise first demonstrated in Formula One. The performance on offer is comparable to a naturally-aspirated 1.4-litre engine with approximately 25% better fuel economy and emissions.

Engine technologies used on the advanced new engine include a Teflon-coated timing chain to reduce friction, a stop-start system for cutting consumption in traffic and a variable-displacement oil pump.

No figures have been released for fuel economy yet, because the next-generation Clio is not finished at this time.

The new 1.5 eco-diesel will return 64.2mpg in the Kangoo and Kangoo van; its first applications. It will be launched in May, followed in June by a 74bhp version. Like the 0.9 petrol it has various efficiency technologies including stop-start.