Internal combustion engines have long received flack for how wasteful they are. And while you can't argue about how inefficient they may be, the truth is that internal combustion has led the way for modern transportation since time immemorial.
Did you know that combustion engines squander up to 75% of their energy, which is either released as engine heat or released through an exhaust pipe? But what if ICE could become more efficient and greener? Would that cast a dent in EV sales?
Researchers from Pennsylvania State University claim to have discovered a technique for converting exhaust heat into energy using a small device that can be mounted on an automobile's tailpipe, according to a report published in the scientific journal ACS Applied Materials and Interfaces. It is called a thermoelectric generator (TEG).
Although thermoelectric (also known as heat-recovery) devices that use temperature gradients to turn heat into energy already exist, the technology is very complicated and hefty. What's more, these devices often need cooling water to maintain the necessary temperature differential.
This is exactly where the new thermoelectric generator system comes in – and it’s rather ingenious. But I must warn you: it might get a little nerdy, so bear with me.
Thermoelectric generators (TEGs) work on the principle of absorbing heat and transforming it into electrical power. When positioned close to a heat source, like a tailpipe, electrons bounce from the hot side to a cold side, generating an electrical current. Bismuth-telluride, a semiconductor material that effectively promotes this electron flow, has been used in TEGs by the researchers.
Maintaining a temperature differential between the device's two sides without compromising efficiency is the difficult part of this equation. In order to address this issue, the researchers developed a heatsink device with fin-like protrusions that are wrapped around the tailpipe, dissipating heat through forced convection. Think of a big fan hooked to the CPU in a gaming computer – it's the same concept.
The prototype produces a maximum output of 40 Watts, which is enough for low-power applications such as charging your phone. The team was able to generate 56 W of electricity when they ran simulations with a car going at a high speed.
Then came the helicopter. When connected to a helicopter's exhaust vents, the system produced 146 W of power. I must admit, it's a minuscule amount of energy in the grand scheme of things, but considering this energy is being recovered and used instead of simply being let go, it's a sizable feat.
Here's what's brilliant about the system: It could easily be installed in the tailpipes and other exhaust vents of existing cars without the need for extra cooling systems, guaranteeing increased efficiency and cleaner energy sources. Although this technology was created especially for cars, it's clear that it has the potential to be used in other kinds of transportation.
Off-road ATVs and two-wheelers could benefit even more, since their exposed exhausts enable more effective heat dissipation without increasing system complexity or weight. Additionally, this technology could potentially be best employed in hybrid vehicles, which would use the electricity produced to boost battery range.
This breakthrough indicates that ICE energy efficiency can still be improved, regardless of its many shortcomings. Sure, electric vehicles might seem like the way of the future, but any advancement that increases the efficiency of combustion engines today is worth the effort.
Source: American Chemical Society
