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Ways to Boost Fuel Efficiency

TA News Bureau


As the Indian economy grows, it is striving to bring fuel efficiency regulations for new trucks and buses. In this interview Benjamin Sharpe, the San Francisco-based Senior Researcher with the International Council on Clean Transportation (ICCT), says India can achieve cost-effective fuel efficiency improvements for commercial trucks and buses by switching to radial tyres and upgrading engine efficiency. The most unique feature of the Indian transportation market is its smaller engine size and power ratings. Fuel efficiency is hit because of lower speeds and high percentage of heavily-loaded trucks. It calls for modernisation of engines and tyre improvements. The Indian experience will benefit other developing countries, he says. Excerpts from the interview

Benjamin Sharpe

Please elaborate on the key findings of your research on fuel efficiency of heavy duty vehicles in India?

There are significant opportunities for cost-effective fuel efficiency improvements for commercial trucks and buses in India in the post-2020 time frame. Our research provides evidence that up to 40per cent in per-vehicle fuel savings are possible compared to a BS IV baseline.
Most of the efficiency technologies we investigated will yield a payback on investment within two years of the initial vehicle purchase. These technologies with a two-year payback can lower fuel consumption by 20 to 35 per cent, depending on the vehicle type and application.

Why do you think that India would greatly benefit if it focuses on engine and tyre improvements for its first phase fuel-efficiency regulation for trucks and buses?

Two key factors have important ramifications for the overall energy consumption of heavy-duty vehicles (HDVs) in India. The first unique feature about the Indian commercial vehicle market is that engines are much smaller and less powerful than comparable vehicles in other major markets—particularly Europe and North America. Due to these smaller engines and lower power-to-weight ratios, commercial vehicles tend to drive much slower in India. This is particularly the case for freight trucks. For example, a recent TCI (Transport Corporation of India) study reported that average truck speeds in India over a number of major routes are between 20 and 40 kilometres per hour. In contrast, representative drive cycles for freight trucks in Europe average about 80 kph, and this jumps to nearly 100 kph in the US.
The slower a vehicle travels, the more tyres tend to make up a larger portion of the vehicle’s overall fuel consumption. Or, to say this another way, the energy lost to aerodynamic drag increases exponentially as a vehicle’s speed increases. An example helps to illustrate the point. For a typical long-haul tractor-trailer in the US, the engine accounts for about 60 per cent of the total energy losses, aerodynamic drag makes up about 20 per cent, and tyre rolling resistance represents roughly 15 per cent. Now in India, while engine losses are still about 60 per cent, due to the much slower average speeds, aerodynamic and tyre rolling resistance losses are 2 per cent and 20 per cent, respectively. Note the significant change in the relative contribution of aerodynamics and tyres for trucks in India versus the US. In India, tyres consume 10 times the amount of energy as aerodynamic do, whereas in the US, tyres only consume about three-quarters of the energy as do aerodynamic losses. So, in summary, smaller engines and slower driving make tyres and engines the most impactful and cost-effective technology areas for efficiency improvements for HDVs in India.

Your study has revealed that tyre rolling resistance accounts for the majority of energy losses after engines, which represent well over half of total losses. In this context what would you recommend that tyre designers should prioritise to become competitive?

In India, we are seeing the trend from bias to radial tyres, which happened in other more developed markets 10 or more years ago. The change to radial tyres yields a number of benefits, including lower rolling resistance (thus, lower vehicle fuel consumption) and longer lifetimes. According to industry experts we have spoken with, bias tyres still make up 70 to 80 per cent of the commercial vehicle market in India, though radial tyres are gaining market share and are expected to eventually dominate sales. In our analysis, the switch from bias to radial tyres provides the most cost-effective efficiency improvements of any individual technology that we investigated. Once radial tyres have been introduced, there are a number of material and design advancements that can be applied to lower the rolling resistance without compromising the other performance and safety parameters of the tyre. This move to so called ‘lower rolling resistance’ tyres yields incremental fuel savings beyond the move from bias to radial tyres.

How will your findings contribute to ongoing efforts in India at improving sustainability and boost green mobility?

Our objective is to provide research and data for the government India in its ongoing development of fuel efficiency norms for commercial trucks and buses. Improving per-vehicle efficiency is one key intervention that policymakers have at their disposal. In addition to fuel efficiency regulations, a comprehensive suite of policies for promoting sustainable transportation will also include voluntary and market-based programmes as well as fiscal incentives.

Can your suggestion for India be a roadmap for other developing countries in Asia as well?

I do think that our findings and recommendations for India can be applicable to other developing countries in Asia. Anecdotal evidence seems to suggest that freight trucks in other emerging markets tend to have slower speeds than we see in Europe or North America. As such, it’s reasonable to assume that tyre and engine improvements will offer cost-effective efficiency improvements in these markets, as we expect they will in India. However, each country or region has distinct market and operating characteristics that can have important implications for what technologies are most attractive, so I think it’s necessary to understand the unique aspects of a particular region before pursuing a given policy or suite of policies.

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