Honda Amaze diesel is India’s most efficient car.

Honda’s highly anticipated Amaze saloon will launch on April 11 with the company’s new made-for-India 1.5-litre i-DTEC diesel engine under the hood. This will be Honda’s first diesel engine in India and it is set to cause a sensation when it’s launched. The Indian market is skewed towards cars that promise more per litre, which explains why the Amaze has already garnered the interest of most Indian car buyers. The Amaze diesel will, in all likelihood, enter the market as India’s most efficient car (if you take the Indian Driving Cycle or IDC figure of 25.8kpl into consideration). Of course, real world figures will be lower. But how has Honda done it? How has it made this car so efficient?

Weight-saving was high priority for Honda when designing this car, which is evident by its use of a thin-walled aluminium engine block, an aluminium head and lightweight cast-iron cylinder liners. In an effort to further reduce weight, Honda has opted for an open-deck construction, unusual for an aluminium diesel engine block, as a closed deck construction is normally considered to be stronger (aluminium blocks in the past were known to suffer from warping under heavy loads).   

What’s more, Honda’s automotive lubricants partner, Idemitsu, has developed a special engine oil with an ultra-low viscosity rating that helps the Amaze achieve its high fuel efficiency figure. Honda has also worked hard at reducing the mechanical friction of the i-DTEC engine, something it has done for years with its petrol motors. Engineers have used shorter and thinner piston skirts in an effort to reduce mechanical friction even further, and these and other changes have resulted in a greatly reduced amount of overall friction. Honda claim a massive reduction in mechanical friction of 40 percent at 1500rpm over conventional diesel motors, and that is huge, especially since the aforementioned engine speed is where diesels normally spin.

All these measures have helped the Amaze set an impressive 25.8kpl mileage figure in the IDC. This figure ousts the Chevrolet Beat diesel’s 25.44 kpl, the Indica CR4’s 25kpl and even the Tata Nano’s 624cc petrol engine that returns 25.4kpl. Again, these numbers are not real-world figures, but are comparable because they are recorded using the same test procedure. All these measures go a long way in helping save fuel, which results in a major disparity in the real-world efficiency figures and IDC figures.

But why are the IDC’s figures recorded so exaggerated? The IDC is the platform used for the industry-approved fuel efficiency figures, which car companies have chosen to voluntarily disclose. Its test involves a cycle that lasts for 1,140 seconds and covers 10km, which translates to an average speed of 31.6kph. There’s lots of start-stop involved and there is negligible amounts of engine revving. The gentle driving technique also involves a fair amount of cruising in top gear. Also, all tests on the IDC are done with the air-con switched off, and this skews the figures even further. Nonetheless, IDC figures do allow for a good reference point for relative comparison between cars.

So, the Amaze will enter the Indian market as the most fuel efficient car, at least based on figures given by the IDC.

Here’s a list of the top 10 fuel efficient cars in India to give you a better idea of what Honda has achieved.

1.     Honda Amaze – 25.8kpl

2.     Chevrolet Beat diesel – 25.44kpl

3.     Tata Nano – 25.4kpl

4.     Tata Indica CR4 – 25kpl

5.     Toyota Etios Liva – 23.59kpl

6.     Nissan Micra diesel – 23.08kpl

7.     Maruti Swift diesel – 22.9kpl

8.     Maruti Alto 800 – 22.74kpl

9.     Chevrolet Sail U-VA diesel – 22.1kpl

10.   Volkswagen Polo diesel – 22.04kpl