Combustion engine gains are not exhausted

Last month California governor Gavin Newsom issued an executive order directing the state to end the sale of new gasoline-powered cars by 2035. Some electric vehicle (EV) enthusiasts hailed it as another bold step in the fight against climate change, but it begs the question of how radically the world’s fleet of cars and trucks will change over the next 15 years.

For the time being, the fossil-fuelled internal combustion engine remains with us as the main method of passenger transport.

While EVs continue to gain US market share, they accounted for only 1.5 per cent of all newly registered vehicles in the first half of 2020, according to analysis from the data firm IHS Markit. In fact, fuel-guzzling sports utility vehicles (SUVs) — which are classed as light trucks with four-wheel drive and a raised clearance for off-road driving — are selling at a faster clip than EVs. In 2018, SUVs captured 46 per cent of the US market for new vehicles. Meanwhile, consumer demand shows little sign of abating, partially due to a slump in forecourt petrol prices since 2014.

Internal combustion engines will, it seems, be with us for the foreseeable future. Therefore, rules around their emissions and fuel economy are crucial. And regulators recognise this. After the 1973 Opec oil embargo, the US National Highway Traffic Safety Administration introduced the Corporate Average Fuel Economy (CAFE) standards, which seek to improve the energy efficiency of the US fleet. Through civil penalties and a credit system, CAFE requirements make it more expensive for automakers to build vehicles with poor fuel economy. Over the past decade in particular, these regulations have become an important tool for reducing emissions.

Across the Atlantic, the EU has taken a different approach. In response to the oil shocks, many European countries raised taxes aimed at lowering fuel consumption, thus beginning an ill-fated love affair with diesel-powered cars. Tax and duty now account for the bulk of consumer prices for petrol and diesel in Europe, in stark contrast to the US, making fuel economy a central factor in the cost of car ownership and use. EU policy has also focused on reducing the average weight of vehicles to enhance fuel efficiency, whereas US standards depend in part on the vehicle’s footprint — the area enclosed by its four tyres. Compared with passenger cars, this has led to less onerous demands for the overall fuel economy of heavier passenger vehicles in the US, including SUVs.

Despite these trends, fuel economy has increased by 30 per cent, or 5.8 mpg, since 2004, mainly due to innovations in engine design. For instance, a report from the US Environmental Protection Agency (EPA) shows that, in 2008, gasoline direct injection (GDI) technology was used in fewer than 3 per cent of all vehicles. By 2019, that figure was estimated to exceed 50 per cent. Instead of port injections, where fuel is sprayed into the intake tract, GDI involves spraying fuel directly into the combustion chamber, raising the compression ratio and improving fuel economy.

The adoption of engine technologies varies among manufacturers. Two leading US automakers, General Motors and Fiat Chrysler, are among the few that have added cylinder deactivation capabilities to conserve fuel when less power is needed in the engine. Ford also joins GM and FCA in offering stop/start systems that shut off the engine when the vehicle is idle — especially useful in urban areas where there is more traffic.

At 58 mpg, the Hyundai Ioniq Blue, a hybrid vehicle combining battery and combustion power, is among the most fuel-efficient vehicle on the US market, excluding EVs.

Michael Evanoff, a senior manager of product planning for Hyundai, says the company has achieved large increases in fuel economy by introducing intelligent variable transmission (IVT), which allows its vehicles to operate more efficiently by keeping the engine within its optimal power range.

In general, industry players are hoping that further “hybridisation” will ease the transition to all-electric vehicles. Honda, the most energy-efficient automaker in the US with an aggregated fuel economy of 30 mpg, is looking to “expand the application of electrified powertrains,” says Dave Gardner, executive vice-president of national operations. Like many automakers, Honda is also working to electrify the bulk of its product line-up by 2030.

But smart regulation is critical to ensuring fuel economy gains are met, say experts. Studies have found that consumers consistently undervalue fuel economy when purchasing a vehicle, and will pay less for fuel savings than what they stand to gain.

“Automakers don’t have the right incentives to offer more efficient vehicles and so, consumers are losing out on these savings,” explains Prof Josh Linn from the University of Maryland.

This year, the Trump administration revised CAFE to mandate annual fuel economy gains of 1.5 per cent until 2025, rather than an implied 5 per cent annual gain implied by this date under Obama-era rules. This rolling back of regulations has happened before. From the late 1980s until 2004, CAFE standards flatlined at around 27.5 mpg for passenger cars and 20 mpg for light trucks. “During that period, we observed how new cars were becoming more and more powerful and improving their acceleration times, but there was a reduction in fuel economy,” says Benjamin Leard, fellow for transport policy at think-tank Resources for the Future.

Consumers consistently undervalue fuel economy when purchasing a vehicle

It is unclear how these regulations will change under the next US administration. Nonetheless, in his campaign for the White House, Joe Biden pledged not just to reverse President Trump’s fuel economy policy, but to “go further and faster.”

One big area for improvement is vehicle testing and monitoring, where the divergence between real-world and official statistics is stark. Although the discrepancies are nowhere near as wide as those reported in the EU before new test procedures were developed in response to the 2015 “Dieselgate” scandal, the EPA typically assumes that laboratory tests understate fuel consumption by 20 per cent. Advancements in vehicle software can change that.

“The technology already exists,” says Prof Linn. “It’s just a matter of collecting information from an odometer, computing the fuel economy, and storing that data . . . But we need to figure out a suitable regulatory structure that deals with consumers’ privacy concerns.”