Clever physics could make your car's turbo more effective.
You'd think that the operating principles of a turbocharger are well understood by now, but it turns out that there's a new, small tweak that could boost a turbo's efficiency even further. According to a new patent unearthed by CarBuzz at the DPMA, Hyundai's engineers have found a way to improve the airflow rate of any turbocharger without significant changes to the turbo itself. At first glance, this new development looks counter-intuitive, but if it works in the way physics prescribes, it could mean improved performance for smaller engines such as the one in the Hyundai Kona N.
This new patent is the result of a careful analysis of pressure distribution around the turbo compressor housing's outlet. It was discovered that, at the junction where the compressor housing joins the first section of the boost pipe, there is a small region that experiences a pressure drop.
Further investigation revealed that, by fitting a boost pipe with a slightly larger diameter than the compressor outlet, the difference in diameter between them will allow for a small parallel and concentric port which generates suction in that area of the pressurized boost pipe. This is due to the kinetic energy of the boosted air flowing past the gap, which results in a low-pressure area around the compressor housing's outlet port.
The implementation is fairly straightforward, with an add-on fitting around the compressor outlet which opens into the boost pipe at a near-parallel angle, fed by a simple supply line from the compressor housing's inlet hose, which is always at atmospheric pressure. This has the effect of introducing yet more air into the boost pipe, increasing the airflow volume after the main body of air had already passed through the compressor.
The advantages of this technique are said to revolve around the added air mass, which improves the ability of the engine to take in more air, regardless of the boost condition downstream of the compressor. The fresh air introduced via this port is also cooler than the pressurized air coming from the compressor, reducing the intake air temperature.
In off-boost situations, the air intake restriction created by the compressor wheel can be bypassed, making for a crisper throttle response before the turbo spools up. And, if the turbo in use is profiled for low-rev response, the fresh air bypass system will allow some extra air into the boost line at high engine speeds to liberate a bit of extra power by again bypassing the (now-restrictive) compressor housing.
Whether this patent will make it into production is an open question, particularly as the industry gravitates toward electrification and away from the idea of producing more efficient combustion engines, but apart from slightly higher manufacturing costs, it wouldn't be expensive to implement and could lead to even higher engine efficiency if it works as planned. Combined with something like Porsche's reinvented turbocharger that we discovered earlier this year, we could be headed to a new age of boosted efficiency - again, assuming that the industry allows combustion to survive. This method could alleviate many turbocharger drawbacks, so the only question remaining is this: How come it took so long for the engineers to develop such a simple but fiendishly-clever idea?