Mazda turned heads when its SKYACTIV-G (as in gasoline) engine achieved the highest compression ratio among petrol power plants. This impressive feat meant that vehicles from the Japanese brand offer, like the all-new CX-5, increased fuel-efficiency and have more torque in low- and mid-speeds.
For starters, Mazda wanted to improve the way the engine burns gas (also known as combustion process). One way to do that is by raising the compression ratio of the power unit to 13:1. However, doing so may cause premature ignition of the air-fuel mixture in the cylinder chamber and high-frequency noise due to high temperature. In layman’s terms, this is simply called engine knocking. Engine knocking may be more than just an annoying sound. It may cause power loss, carbon build up, and may damage your engine in the long run.
Mazda’s solution to this is simple yet ingenious - a 4-2-1 exhaust system, multi-hole injectors, and a redesigned piston cavity.
In a nutshell, the uniquely designed exhaust manifold uses a 4-2-1 pipe layout to prevent hot residual gases from re-entering the engine cylinders, effectively lowering temperature inside. Moreover, the exhaust manifold must be long enough, 600mm to be exact, so that gases don’t “accidentally” flow back into the chamber.
Meanwhile, Mazda engineers made use of multi-piezo injectors to enhance air-fuel mixture, quicken the combustion process, and help cool the cylinder. On the other hand, a piston cavity was adopted to prevent the flame caused by the ignition of air-fuel mixture from reaching the cylinder head, generating cooling loss.
What does this mean for current and future owners of Mazda vehicles?
Mazda's SKYACTIV-G engine is certainly innovative. The technology found in these powerplants solved a long time problem in improving the efficiency of gasoline powered combustion engine.
Thanks to its high compression combustion, the latest generation of engines can now come up with a 15% increase in fuel economy and additional torque in low- and mid-speeds. These numbers would come in handy when it comes to driving uphill in heavy traffic situations or in the daily drive to work.