Over the past twenty-five years, combustion improvements, efficient filters and catalytic converters have virtually eliminated emissions of nitrogen oxides and particulate matter from vehicle traffic.
But the problem of carbon dioxide emissions contributing to the greenhouse effect still remains to be solved.
Today's diesels have an efficiency level of about 40%. Research indicates that a level of over 50% can be achieved.
We are working on a multitude of solutions that will contribute to increased fuel efficiency in the future. This includes engine combustion efficiency, powertrain friction reduction, waste-heat recovery, vehicle rolling resistance, air drag reduction, and improved controls.
The Volvo Group has a long history of improving and optimizing combustion, but this continues to be a critical area for efficiency gains. This includes fundamental work with fuel injection frequency, timing, shaping at pressures in excess of 2500 bar, ever improving turbochargers, piston bowl shapes and engine breathing.
Waste heat recovery
Although diesels are the most efficient engines in common use, still over half the fuel energy is wasted as heat in the exhaust and cooling systems. We are working to develop Rankine bottoming cycles that can work within vehicle constraints to extract useful mechanical or electrical energy.
Exhaust heat exchangers
One technology that reduces nitrogen oxide emissions involves re-circulation of exhaust gas into the engine cylinders. In this process, a heat exchanger can be used for recuperating unwanted heat carried by the gas. This benefits the exhaust gas after treatment system and reduces fan engagement.
Large heat exchanger systems may require more space than is currently available on the tractor, meaning that heat exchange systems may be fitted on truck trailers in the future.