29/1/12

Overview: Renault Energy dCi 110, TCe 115

Following the introduction of the 1.6-litre R9M diesel last year, Renault is introducing two new power-units into its Mégans, Scénics and Grand Scénics.

The first of these is the Energy dCi 110. Renault describes this as an ‘extensive metamorphosis‘ of the familiar 1461cc K9K, which has been available in 75PS, 90PS and 110PS forms for some time. In the Scénic, the new version delivers fuel savings of around 16 per cent. over the NEDC test cycle compared with its predecessor, with an overall return of 68.9mpg (4.1l/100km) and 105g/km of CO₂. Torque improves by 20Nm to 260Nm.

The ‘metamorphosis’ of the K9K amounts to an application of the techniques and approaches used on last year’s Energy dCi 130, otherwise known as the R9M. The most obvious and familiar innovation is an automatic stop-start system. Additionally, the car’s kinetic energy on the overrun is recovered and fed into the battery, allowing the generator to be disconnected when the engine is under load, assuming its state of charge is adequate.

Like the dCi 130, the new 1.5-litre engine is equipped with low-pressure EGR. This allows for an increase in boost pressure from the turbocharger. Exhaust gases are recovered further downstream than is normal, and thus at a lower temperature and higher gas density, after passing through the turbocharger’s primary (driver) turbine and particulate filter. The recycled exhaust gases are cooled along with charge-air in the intercoler and used for combustion a second time. This so-called ‘cold loop’ enables emissions of nitrogen oxides to be cut more efficiently than is the case with a conventional high-pressure EGR, while engine efficiency is superior and combustion is of a higher quality.

A thermostat-controlled variable-rate oil pump is used. The capacity of the pump is adjusted automatically according to the output of an oil temperature sensor to allow for changes in the viscosity of the oil.

New turbocharger architecture is used, reducing pumping losses by simplifying the path taken by intake air. The blower itself has a variable-geometry nozzle and low inertia turbine.

New injector nozzles are used with a novel spray cone angle; and finally, the engine has had a friction audit.

The second new engine for the spring of 2012 is the 1198cc TCe 115 petrol unit, otherwise known as the H5Ft, which replaces the existing 110PS 1.6-litre engine with a fuel saving of roughly 20 per cent.

The Energy TCe 115 is the first Renault petrol engine to use direct fuel injection and turbocharging. This new 1198cc block offers more headline power and torque — up from 110PS to 115PS and from 150Nm to 190Nm — than its 1.6-litre forebear. Ninety per cent. of maximum torque is available from 1650rpm. The Mégane hatch powered by this engine uses 5.3l/100km over the NEDC test cycle (equivalent to 53.3mpg), a saving of just under 1.5l/100km; CO₂ emissions stand at 119g/km.