Wind the clock back 20 years and you will see that diesel power dominated Indian roads, thanks to the advent of Fiat’s 1.3-litre diesel engine being licensed by Maruti-Suzuki, which also served in Fiat and Tata vehicles. Diesel power accounted for over half of all new car sales. New-generation diesel engines achieved power roughly equivalent to a standard small petrol engine while returning fantastic efficiency figures. At the same time, European carmakers in particular managed to convince car buyers that diesels were clean.
It was the repudiation of the last point that brought the Diesel House of Cards crashing down. While diesel engines are still extremely efficient regarding carbon emissions, the fact that they are ‘compression’ engines was the issue.
High compression ignites the fuel-air mixture in a diesel instead of a spark plug, as in petrol engines. These high compression ratios, in excess of 18:1, also typically cause inert nitrogen to react and form nitrogen oxides, a.k.a. NOx. That, coupled with particulate emissions and the fact that multiple German automakers, especially Volkswagen, were caught cheating in emissions tests, led to huge fines and a global decline in diesel sales.
‘Dieselgate’, as it came to be known, was also made a stick to beat diesel within India. The Supreme Court first banned the sale of large diesel engines and then imposed a 10-year registration mandate on them in the National Capital Region (NCR). Diesel sales collapsed, and some manufacturers, such as Maruti-Suzuki and Skoda Auto-Volkswagen, exited the arena completely.
But here is the funny thing: diesel sales have been increasing in India over the past few months. Some manufacturers, such as Mahindra and Tata, have a strong diesel portfolio. Furthermore, the advent of GST 2.0 norms, which reduced cess on larger diesel engines, has seen diesel power capture over 18 per cent of the market in July, according to data from the VAHAN portal run by the Ministry of Road Transport and Highways. And let us be honest, the chaos around the ethanol-blending programme might have played its part as well.
The fact is that modern Bharat Stage 6 and the upcoming Bharat Stage 7 (BS7) emission norms have actually made diesel engines supremely clean. In fact, BS7 norms mandate ‘On Board Monitoring’, which will actually measure emissions on a real-time basis. These norms also make vehicles ‘fuel neutral’ regarding emissions, as diesel vehicles will be measured by the same yardstick as petrol and CNG vehicles.
Diesel isn’t dead yet
The Supreme Court and the government should seriously relook at the ‘ban’ on diesels plying beyond 10 years in the NCR. Although these new norms will make smaller diesel vehicles quite expensive, other technologies are coming in. Maruti-Suzuki is calling CNG the ‘new diesel’, and at the launch of the MG Hector Tomahawk this past week, Parth Jindal described plug-in hybrid technology as having the efficiency of a diesel. And frankly, this is purely down to efficiency — the good old ‘Kitna Deti Hai’ story.
I wish it was simple, though. A good diesel engine is about more than just efficiency. It is about the raw torque churned out when you start up a diesel motor. It is why I feel Skoda Auto is planning to launch the new Skoda Superb with a diesel motor from the middle of next year.
There are a couple of other things. CNG has become extremely popular, and with both Maruti-Suzuki and Tata Motors installing ‘underfloor’ CNG tanks that do not compromise on luggage space, CNG vehicles are more practical than ever before. There has also been a huge expansion of the CNG network across the country. But if you were to drive past a CNG pump and see the long queues, I just don’t see how one could choose a CNG vehicle over a pure battery-electric vehicle. If you’re going to waste time refuelling or recharging, what difference does it make?
But if you live somewhere where the queues are shorter—and more CNG pumps are coming up—CNG still makes some sense, although supplies from Qatar, in particular, could still be impacted by any further flare-ups.
As for PHEVs, there is an argument for them. While in both the case of CNG and PHEVs I would still choose a fully electric vehicle, I understand the reasoning. Although, if you really still have range or charging anxiety, the best solution is an Extended Range Electric Vehicle (EREV).
But there is always still diesel. The sheer brute force of the compression engine, especially for heavy machinery, will ensure its longevity. And I feel that gradual improvements to emissions technology and how we can clean out exhaust emissions might mean that diesel engines should be around for private cars and SUVs for some time yet.
Kushan Mitra is an automotive journalist based in New Delhi. He tweets @kushanmitra. Views are personal.
(Edited by Prashant Dixit)