Small is beautiful as carmakers downsize

Less is more with the next generation of 1.0-liter car engines as the auto industry shrinks engine sizes to improve fuel economy and lower carbon emissions.
Car engines are shrinking as manufacturers squeeze more power for less fuel and emissions out of .../ Credits: Reuters
Henry Ford famously said that customers could have his company’s Model T cars painted “any colour so long as it is black.” Today, Ford and other carmakers offer a few more options. Unlike in Henry’s time, what the customer wants the customer gets.

What customers (and governments) want now and in the future are cars that consume the minimum of fuel and produce the minimum of CO2 and other pollutants. These are the market demands of an urbanizing world of rising oil prices and stricter environmental and public health laws.

So carmakers are offering a few more engine options, namely smaller engines.

By reducing engine capacity to around the 1.0 liter mark, by developing gasoline engines with three cylinders instead of the usual minimum of four, almost all major manufacturers are striving to improve fuel economy, reversing the previous industry trend towards bigger, more powerful engines. These days small is beautiful.

In Ford’s case, it launched its 1.0-liter, three cylinder EcoBoost engine in its Focus model in May 2012, reportedly the smallest engine the company has built since the 1930s. The EcoBoost is 30 percent lighter than the 1.6-liter model it is replacing and, according to Ford, it achieves a 15-20 percent improvement in fuel economy but without sacrificing power or performance.

Volkswagen took the wraps off its 1.0-liter, three cylinder engine at the Frankfurt motor show in September 2011. It powers the ‘up!’ car, designed specifically for urban motoring. In city driving Volkswagen claims that the up! averages between 5.0 and 5.9 liters per 100km (48 to 56 mpg) depending on the model.

Smaller still is the Fiat TwinAir engine, used in the Fiat 500, which has only two cylinders with just 0.9-liter capacity and yet produces power similar to some 1.4 liter engines using much less fuel and producing just 95 grams of CO2 per kilometer, according to Fiat.

“All global OEMs are now focussing on urban passenger vehicles which mean smaller vehicles...ideal targets for 1.0-liter and sub-1.0-liter engines...which we expect to account for about 3.5 to 4.5 million units annually by 2020, about five percent of the total market,” says Kaushik Madhavan, Program Manager Automotive & Transportation at market analysts Frost & Sullivan.

This engine downsizing is probably the most effective way for the industry to cut carbon emissions from vehicles in the near term because internal combustion engines will continue to dominate the auto market for years to come.

“The fuel economy and emission characteristics are much better than older generation engines and since the downsized engines operate at a higher load, the fuel economy is much better, especially in gasoline engines,” says Madhavan.

Climate impacts: gasoline vs diesel

Gasoline engines also have an advantage over their diesel counterparts which have become increasingly popular recently because of their improved fuel economy and CO2 emissions.

Unlike diesel engines, gasoline units don’t emit nearly as much nitrogen oxide (another greenhouse gas) or soot (particulate emissions)—a major impact on air quality. In June 2012, the World Health Organization declared for the first time that diesel fumes are carcinogenic.

A key driver for downsizing is the introduction by governments of taxes and incentives that gradually increase or reduce based on a vehicle’s level of CO2 emissions, thereby nudging consumers towards less polluting cars.

In Germany, for example, vehicles with CO2 emissions below 110 grams per kilometer are exempt from road tax. In the UK, the exemption starts below 100 grams per kilometer and owners don’t have to pay London’s congestion charge.

Meanwhile in Spain registration tax is waived if a car emits less than 120 grams per kilometre and in the United States new emission standards require carmakers to achieve a fleet average fuel economy levels of 34.1 miles per gallon (8.3 liters per 100km) by 2016 and 54.6mpg by 2025.

By 2020 in Europe, incentives will have turned into regulations. The European Commission plans to set CO2 emissions to 95 grams by then. So far EU regulations have aimed at a CO2 limit of 130 grams by 2015.

Technologies under the hood

How have manufacturers managed to go so small?

By applying technologies normally found on larger vehicles to smaller engines, says Madhavan. “Boosting, variable valvetrain, and GDI (Gasoline Direct Injection) are enabling aggressive downsizing without compromising on performance characteristics,” he points out.

Boosting or turbocharging uses exhaust gases to drive a turbine to force more air through the engine and so enhance combustion. GDI, also known as fuel injection, sprays fuel at high pressure into the engine cylinder, again making combustion more efficient and powerful. The EcoBoost engine, for example, uses both direct fuel injection and turbocharger technology.

The TwinAir’s secret is the way it manages air intake into the combustion chamber via the engine valves, or valvetrain. Instead of using a standard camshaft it has electro-hydraulic controls which manage the airflow more precisely thereby improving combustion efficiency.

Manufacturers are both converting existing engine models into smaller versions by removing cylinders and adding advanced technologies, such as with the EcoBoost, and developing entirely new engine platforms from scratch, like the TwinAir.

“This will only increase towards 2020,” predicts Madhavan, looking forward to a time when small engines will not just be an option but quite possibly the norm.

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Comments (1)

Marvin McConoughey: 13.12.2013, 04:48

The future may well be one of almost universal partnership of internal combustion engine and electric motor. Both devices are developing rapidly, as is the associated battery technology. Along with this, power recovery turbines are a distinct possibility and variable inlet turbochargers may become as common on gasoline engines as they now are on diesel engines. The currently high cost of materials to cope with the higher temperatures of gasoline engines is the largest obstacle.

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