Car makers are reworking their strategies, even as the differential in price continues to fuel the preference for diesel amongst buyers.

The skew in favour of the diesel engine option, where available, is so heavy that it is bordering on seeming like an exodus, with almost 60 per cent to 80 per cent of sales coming in from the diesel. Cars with no diesel engine versions are almost being abandoned by the wayside. Agreed, diesels are inherently more fuel efficient than their petrol counterparts. Also current day common rail injection technology has raised the refinement levels of diesel engines to a point where they are only marginally noisier or prone to more vibrations than the petrol. But, they are also more expensive and in some cases even poorly kitted out compared to petrols.

That hasn't deterred buyers, even those that are unlikely to put their diesel cars to extensive use. Competition has been intense with almost every car maker (except Honda) offering diesels in their portfolio and the clamour to bring in product differentiation has also been on. With the budget behind us and the uncertainty regarding diesel off our minds, round two is set to begin.

Renault India had launched the Fluence sedan in May last year. The executive sedan had been offered with Renault's two-litre petrol engine and its popular 1.5-litre K9K diesel engine, with the former being available with a CVT II automatic transmission.

In six months, the Fluence has gained visibility on the road. However, what must have weighed on the minds of the folks at Renault would have been its inability to fully capture the imagination of the diesel buyer in the segment. The Fluence's diesel E4 variant was the top-end and Renault is said to have received considerable feedback regarding the need for ‘more' from buyers of this variant.

With much of the driving amongst urban buyers being concentrated within the city, the key demand must have been for a bit more low-end torque and a cabin that is as loaded as the top-end petrol variant. Renault has reacted by improving the performance of the K9K diesel engine, boosting the numbers under all characteristics. The new Fluence E4D essentially sports the same engine, but is the latest generation of this very popular K9K.

Engine tweaks

The 1.5-litre dCi engine gets a boost in performance and refinement too thanks to a few targeted improvements to reduce load losses.

First, the variable geometry turbo charger gets a new optimised fan that leads to easier flow of compressed air. The air intake path has also been simplified and shortened to improve the performance efficiency of the turbocharger. The turbo itself is a low-inertia unit now, which leads to improved response at low engine speeds.

The new batch of changes to the engine also includes piezo injectors that manage to significantly improve combustion performance simply by optimising and making more precise the fuel spray pattern. The change in pattern ensures better, more complete combustion and lower post-combustion losses in the cylinders. In terms of hard numbers, what all these changes lead to is also an improvement in the power and torque that the engine delivers. Peak power is up about 4 per cent at 110PS and is available from 4,000 rpm (106PS earlier and now in the E2). Peak torque continues to be the same 240 Nm (as in the E2), but it is now available from a lower 1,850 rpm compared to 2,000 rpm earlier.

Though the numbers don't seem to talk of a significant upgrade, on the road, the performance difference that the engine delivers becomes quickly evident. There is a spring in the step of the Fluence E4D. Low-end torque and its benefits can be appreciated more while negotiating city traffic and while trying to get away from the crowd in sticky junctions. I drove the new Fluence diesel from Chennai along the East Coast Road leading upto Pondicherry. Keeping the engine just above the 1,000 rpm level is enough to keep it on alert standby. From that point on, the eagerness to rev and accelerate quickly while staying in gear is a good pointer to the effectiveness of the changes made in the E4D.

The flatter torque curve and the fact that it peaks quicker also means that the engine manages to remain knock-free even lower down the engine rpm range compared to the earlier spec. However, Renault engineers have still decided to add a gear shift indicator in the instrument cluster, which prompts the change with an up or down arrow indictor lighting up.

In cabin refinement levels have improved marginally. But in terms of features, the new E4D gets all the trim carried over from the existing E4 variant. The ARAI rated fuel efficiency of the new variant is 20.4 kmpl.

With the new Fluence E4D, Renault India is even more confident of taking on the competition from the other diesel cars in the segment. With a car that has gotten a boost in performance and continues to be well stocked with goodies, I don't see why it can't. The new variant has been priced at Rs 15.2 lakh (ex-showroom, Delhi) and it will join the Petrol E4 and the diesel E2 variants.

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