Engine boost systems are now the standard for any auto today, when the manufacturer can no longer compromise power with efficiency and emission standards. Boost systems also enable smaller engines to reach comparable power to larger engines without the additional weight and displacement. This post will dive deep into the components of contemporary boost systems and focus on what they are doing and how they influence the engine.
1.What is a Boost System?
At the heart of the engine boost system is an air-air compression process that builds up the air-fuel mixture in the engine’s combustion chamber. In doing so, more oxygen is available for burning, which means more fuel. What’s the net result is an enormous boost in power output without expanding the engine size.
The most commonly used Boost systems are found in performance vehicles, but the system also exists in small fuel-efficient cars, since they make high power without overheating the car. There are basically two types of boost systems: turbochargers and superchargers.
- Turbochargers: The Generally Used Boost Unit.
The turbocharger is the most common boost system found in today’s vehicles mainly because it pumps power from exhaust gases. A turbocharger consists of two main parts, a turbine and compressor attached by a shaft. The exhaust gases that exit the engine spin the turbine which in turn spins the compressor. The compressor rotates, pulling more air into the engine.
What Works: The turbocharger is attached to the exhaust manifold. Running the engine, combustion gases ejecting from the chambers of combustion turn the turbine blades. That motion moves the compressor to pull in air, squeeze it and push it into the intake manifold of the engine.
Advantages: Turbochargers are extremely energy efficient because they make use of exhaust gas waste energy. This improves overall engine performance and provides massive power increases without the requirement of an immense engine.
Problems: One of the biggest problems with turbos is “turbo lag,” or the time between applying the brake and the turbocharger actually starting. This delay occurs because the exhaust gases take time to generate sufficient pressure to rotate the turbine. The modern twin-scroll and variable-geometry turbochargers are designed to alleviate this delay.
- Superchargers: Power at Once.
Superchargers run on the crankshaft instead of gas like turbochargers. This connection directly to the engine means that superchargers deliver power almost instantly — not the wait that you get with turbos. But it does come at a cost of increased power because the supercharger consumes engine power to run.
The Process: A belt attached to the crankshaft of the engine drives the inner rotors of the supercharger which draws air from the intake and propels it into the combustion chambers.
Benefits: Superchargers instantly boost at any engine speed, and are perfect for any application that requires immediate throttle action.
Problems: The major downside to superchargers is that they drain more fuel from the engine than turbochargers, thus decreasing fuel economy.
4.Intercoolers: Preventing overheating of Compressed Air.
Both turbocharged and supercharged cars also utilize an intercooler, a heat exchanger that chills the compressed air before it enters the engine. When compressed, the temperature of air increases and it is lighter and more available to burn. An intercooler thaws this air to make it heavier and thus better for combustion.
Air-to-Air Intercoolers: These move the cooled air through a set of pipes and outside air cools the air that gets into the engine.
Air-to-Water Intercoolers: Water heats the compressed air and is reabsorbed by a radiator.
- Wastegates: Overboost Prevention
A wastegate is one of the key parts of turbocharged engines. Its sole purpose is to limit the exhaust gases running into the turbine, and not increase boost pressure beyond optimum conditions. Too much boost from the turbocharger can produce knock or even wear away the engine components.
Outside Wastegates: These are buried outside the turbocharger and blow overflow exhaust gases into the atmosphere or back into the exhaust system.
Internal Wastegates: Located inside the turbocharger housing, more compact, used most of the time in factory-equipped turbocharged engines.
- Blow-off Valves: Boost Pressure Control
Another critical piece of equipment for a turbocharged engine is a blow-off valve (BOV), which will vent the excess pressure when you close the throttle. If you disconnect the throttle when shifting gears or slowing down, the compressed air will find nowhere to go, leading to compressor surge and turbocharging failure. This pressure escapes via the blow-off valve which keeps everything quiet and clean.
- Boost Controllers: Customized Power Supply Control
Boost controllers allow drivers to adjust the amount of boost pressure in the system. Electronic boost controllers are also standard in today’s vehicles, with adjustments made in real-time as the vehicle is driven. But manual boost controllers are easier but offer less range.
Conclusion
Engine boost technology is a vital development in the automotive industry today that makes small and less efficient engines go big with power. By grasping the important components—turbochargers, superchargers, intercoolers, wastegates, blow off valves, boost controllers—you’ll understand how these components work to get the most from your engine. Whether it is performance improvement for your car or simply learning more about automobile technology, engine boost systems provide a fun look into the future of high-performance, high-efficiency motoring.
