Legislators are pushing for higher fuel economy to reduce carbon dioxide emissions, but this typically means smaller engines with less power.
For most Americans, less power isn’t an acceptable form of transportation, which keeps sales of vehicles with better fuel economy lower than it should be. Automakers are working hard to develop engines that are just as powerful as their gas-guzzling counterparts without sacrificing fuel economy.
One technology that is seeing a resurgence is the turbocharger. A turbocharger is basically an air pump that is driven by the exhaust. The faster the engine runs, the more air is pumped into the cylinder for compression, which increases power.
At first, this may seem counterintuitive, to add power to increase fuel economy. Combining turbocharger technology with smaller engines does exactly this, such as in the case of the Ford Fiesta’s 1.0ℓ i3 engine, which develops the same power as the larger 1.6ℓ but up to 30% better fuel economy.
Current turbocharger technology does have one limitation regarding the laws of physics, because it can only charge up to a certain speed, called the surge line. Internal aerodynamics limit the power that the turbocharger can deliver, so the waste gate opens to bleed off pressure past the surge line. Honeywell is developing a new design that can extend the surge line and help the turbocharger deliver more power over a larger range.
In order to gain a better understanding of the limitations of current turbocharger technology, Honeywell has been working with the University of California at Berkeley. Honeywell’s ported shroud turbocharger recirculates excess airflow instead of bleeding it off. This new design could allow for better power delivery from the turbocharger, further reducing the size of the engine to increase fuel economy without sacrificing power.