Fuel efficiency and air quality are two things that are taking center stage with generator manufacturers. This is because there is a goal to increase the efficiency of the units, while reducing emissions.
Since the internal combustion engine was developed, designers have looked for methods to improve engine performance. Without getting into the overall engine function too much, as it is the same as how a car engine operates, there are two ways in which standby generators can function and those ways are natural aspiration and turbocharging.
In natural aspiration, it is during the intake stroke that a vacuum is created by the air drawn in by the withdrawing piston. That air is brought into the cylinder. When an engine has a carburetor, it atomizes fuel and adds it to the air so that the intake manifold sucks it in. This delivers to the cylinders. If the engine is fuel injected, then fuel is vaporized and injected into the manifold. If the engine is direct injection, the fuel is injected directly into the cylinder, bypassing a step or two when compared to the other.
It all comes down to atmospheric pressure and how it pushes air into the cylinder. This means that changes in altitude can affect how much air the engine has to operate.
A turbocharger operates on high-pressure exhaust that exits the engine. The exhaust expands and has a lot of energy in the form of velocity and heat. That energy is what increases energy efficiency and power.
While all of this may seem like Greek, the point is that a turbocharged engine works well in standby generators because they are efficient and use little energy from the turning engine. A generator engine must turn at a fixed speed because it doesn’t have an accelerator like a car, which means there is no power lag as the turbocharger itself accelerates.