BS IV will go into effect next year, and India had planned to implement BS V in 2019 and BS VI in 2021. Then, in January, Roads Minister Nitin Gadkari announced that the country would skip BS V and move up the implementation date for BS VI to 2020.

As equivalent standards have done in other countries, BS VI is expected to force car and truck manufacturers in India to employ a variety of emissions control technologies – diesel particulate filters, exhaust gas recirculation, selective catalytic reduction. And as they have elsewhere, these technologies will exert restrictions on engine oil formulations, K.K. Gandhi, executive director for technical matters with the Society of Indian Automobile Manufacturers, told the ICIS Indian Base Oils and Lubricants Conference here April 5.

The main restrictions in developed markets have been to limit the use of sulfated ash, phosphorus and sulfur – all of which had been popular ingredients in engine oil formulations. Collectively the industry refers to those substances as SAPS.

Lubricant performance would be critical at BS VI levels, Gandhi said. Future engines will [employ] diesel particulate filters or selective catalytic reduction or three-way catalysts or combinations with catalytic convertors. These after-treatment devices require low SAPS fluids. Normal SAPS oil may not be sufficient.

Gandhi suggested that formulation technology developed in other markets may not fit neatly into Indias. For one thing, Indias cost-conscious market may have difficulty swallowing the prices of todays low SAPS products.

Currently low SAPS oils are formulated with synthetic base stock, he said, alluding to the fact that synthetic base stocks carry higher expenses than more conventional mineral base oils. The future challenge is to have cost-effective mineral based low SAPS oils.

Diesel particulate filters tax engine oils in another way. One of the common ways for engine designers to eliminate the soot that collect in the filters is by programming them to delay fuel injection when filters become, for example, 45 percent full. Delaying injection – called post injection – causes the fuel to burn hotter, hot enough to burn off the soot. But post injection also allows unburnt fuel to creep into the oil sump, where it collects and dilutes the oil, especially if the fuel contains biodiesel.

Dilution can compromise oil performance, so formulators make them more robust. According to Gandhi, though, the impact of soot will be exacerbated in India because of the governments decision to relax cleanliness standards for diesel even as it tightens emissions standards.

This would result in more heavy ends present in the diesel, resulting in an increase in particulate matter, leading to frequent regeneration cycles and faster deterioration of the DPF, he said. He predicted that the oil and auto industries will have no choice then except to reduce oil drain intervals.

Gandhi warned that the lower diesel standard will cause dirtier engine environments that lead to increased deposits on valves and cylinder heads and increased coking on fuel injection nozzles.

DPFs and Euro VI engines have never been evaluated with such relaxed levels of fuels, he said, adding that Indias fuel regulation will be equivalent to BS II when the BS VI emission regulation takes effect. It is an extremely risky situation.