New technologies could save petrol and diesel power
29 August 2017
With the environmental credentials of traditional internal combustion engines and especially diesel much maligned following the Dieselgate scandal, vehicle manufacturers are increasingly switching to low and zero emission alternatives.
Petrol power emits higher CO2 levels, and so has led manufacturers towards diesel, which emits less and therefore helps them achieve a lower overall carbon footprint with their fleets. However, this has resulted in other consequences with higher levels of nitrogen oxides (NOx), which are now known can cause serious health issues and have been linked to further air pollution issues. Yet due to EU economy regulations, diesel helps carmakers meet strict guidelines, meaning their hands are tied when it comes to fuel technology. With these restrictions tightening further, manufacturers are now left with lots of diesel power, and nothing they can do with it.
Some manufacturers are trying to develop technology that will allow them to continue running petrol vehicles, with Mazda launching a new engine, the SkyActiv-X, which does away with spark plugs and works on the same principle as a diesel, using compression to produce the ignition of fuel and therefore making the engine more efficient and less polluting.
Now, vehicle technology and systems provider Delphi has developed a fuel saving technology using petrol, which would improve efficiency figures without the risk of further pollutants. The company believes that combining two emerging technologies can boost petrol efficiency, possibly by as much as 19%, bringing them in line with diesel, while preserving the low-end torque that diesel drivers are accustomed to.
Delphi's proposal combines its 48-volt mild hybrid system with a new type of cylinder deactivation it calls Dynamic Skip Fire. Both systems are ready for production, Delphi says, though neither is likely to arrive before 2020. The 48-volt system and Dynamic Skip Fire can be used separately but complement each other by increasing engine efficiency at both low and high speeds.
General Motors (GM) is likely to embrace one of the two systems when it introduces the next-generation Chevrolet Silverado and GMC Sierra late next year. With Dynamic Skip Fire, it would replace GM's current cylinder deactivation system, which boosts fuel efficiency by cutting off four cylinders of a V8 engine and two cylinders of a V6 when not needed.
Yet the technology would be more critical in Europe and China, where Delphi is now focusing its marketing efforts. In many European countries, diesel vehicles account for nearly half of new-car sales. But diesel's future is in doubt because of tightening emissions rules, expensive after-treatment systems and the Volkswagen Dieselgate scandal.
Meanwhile, researchers at German vehicle technology supplier Bosch have developed synthetic fuels, whose manufacturing process involves capturing CO2. This means that this greenhouse gas can become a raw material from which synthetic petrol and diesel can be produced, and when produced together with renewable energy sources, the fuel is carbon-neutral.
Bosch management board chairman Volkmar Denner comments: ‘Synthetic fuels can make gasoline- and diesel-powered cars carbon-neutral, and thus make a significant contribution to limiting global warming. Achieving our future climate targets calls for other intelligent solutions apart from electromobility.’
Synthetic fuels are made solely with the help of renewable energy. In a first stage, hydrogen is produced from water. Carbon is added to this to produce a liquid fuel. This carbon can be recycled from industrial processes or even captured from the air using filters. Combining CO2 and H2 then results in the synthetic fuel, which can be gasoline, diesel, gas, or even kerosene.
Bosch experts have put an exact figure on the contribution that could be made solely by the European car fleet: by 2050, the use of synthetic fuels as a scheduled supplement to electrification could save up to 2.8 gigatons of CO2, or 2,800,000,000,000 kilograms. That is three times Germany’s carbon dioxide emissions in 2016.
Yet effort will still be required before synthetic fuels can become a reality in everyday motoring. The processing facilities are expensive to set up, and there are only a few test plants at present. However, the German Ministry for Economic Affairs and Energy is supporting synthetic fuels as part of its alternative energies in transportation initiative.