Engines using gasoline & diesel are not going away anytime soon & automakers are embracing turbo-charging to chase high fuel economy targets set by government laws & to clean up emissions with a lower mass engine setup with higher thermal efficiency by use of direct injection & turbocharging. Think Ford Eco-Boost
Turbo 2.0L Engines Nearly Ubiquitous
Automakers are embracing application of 2.0L 4 cylinder gasoline engines with direct injection & turbocharging to give V6 levels of power with lower engine weight & higher thermal efficiency which translates into cleaner emissions & improved fuel economy while also giving more torque earlier & greater engine performance with minimal throttle engagement lag if the turbo charging system optimized near the exhaust header in a compact intercooler enhanced configuration.
Hot Gas Energy Recovery
Exhaust heat & pressure energy recovery by the hot side of the turbocharger spools up the turbine shaft connected to the pressurized cold size of the turbo to produce intake boost pressure for the engine air intake & fuel injection system to shove more air & fuel into the engine at higher pressures to support cleaner more complete combustion by utilizing direct injection of the fuel into the pressurized air. Automakers usually keep boost levels around 7-10 PSI in order to improve reliability & longevity of the engines. The latest vehicles are using even higher boost pressures possible because of the fuel cooling effects of direct injection that minimize risk of pre-detonation or engine knock which could damage the valves.
Thermal Pressure Stress Abatement
Turbocharging puts more thermal & pressure stresses on the engine because of heat energy trapped in the hot side of the turbo & losses in the turbo. Pressurized oil cooling the turbocharger important to prolong the life of the turbo's bearings between the hot & cold side essential for long operating life of the spindle containing the conical shaped compressor fan assemblies that convert heat & pressure in the exhaust to mechanical energy to spin the cold side boost pressure fan in order to create pressurized air for the engine intake system. Applications of more piston rings, friction reduction methods to make the cylinder wall precisely textured to hold a thin film later of engine oil sprayed onto the piston skirts by specialized oil injector channels. High pressure oil pump to accommodate oil cooling turbo-charger & additional lubrication in the engine. More & better quality main bearing in the crank. Forged connecting rods & pistons. Sodium cooled valves. There are many ways to improve the engine with advanced metal alloys & hybrid material science heat pump heat sink heat extraction & cooling techniques //
Enhancing Engine & Turbocharger Life
Spraying engine oil at the piston skirts inside the engine & applying a turbo-timer are other methods to improve engine life & turbocharger life. Spraying oil at the piston skirts help to cool the piston & maintain better sealing with the rings which makes sense given the extra intake stroke pressures created by the turbocharging boost pressure. A turbo-timer keeps engine oil lubricating & cooling fans running when you shut down the vehicles so as to prevent oil vapor burning in the lubricating channels in the center of the turbocharger where the bearing for the axial compressor & recovery turbines are spinning at up to 100,000 RPM. By pumping oil & keeping these bearing cooler it enhances bearing life of most turbocharger designs.
Direct Injection Cools Combustion
More boost possible at engine safe long life operations with direct injection & automakers are going to higher 12-20 PSI boost ranges by exploiting enhanced heat rejection of the engine & turbo system as keeping the fuel air mix cooler a balancing act since pressurizing air increases its temperature in accordance with physics, which is why an intercooler to cool the pressurized air from the turbocharger so as to keep the intake temps lower which enables better thermal efficiency & cleaner cooler combustion with direct injection enable more compression without causing premature detonation that can easily damage valve systems
Continuously Variable Intake Valve System
Freevalve PLC pneumatically actuated continuously variable electronically controlled PWM system similar to the same electrical controls used to modulate fuel injectors & same direct injection control methods used to actuate the intake valves in a variable way to enable more engine operating modes that further enable more engine power output & more torque with cleaner emissions & longer engine life.
Turbocharged Motorcycles on YouTube / click links to watch
This cool article explains the popularity of 2.0-liter engines with turbo or supercharging
Why so many cars have 2.0-L Turbo engines
Optimization of Turbocharger system
1. Placement of low inertia variable geometry electronically controlled into exhaust manifold or exhaust header as close to the exits of the exhaust valves in the engine to get the hottest gas & highest velocity gas to minimize turbine spool up lag. Variable geometry turbocharger allows the ECU to further optimize boost pressure creation while minimizing lag with a custom tuned map similar to ignition & fuel injection maps for electronic control thereof.
2. Oil cooling the turbo charger & making it out of non-rusting high temperature creep resistant metals or ceramics & keeping the bearing system well lubricated with clean filtered & cooled engine oil or lubricating oil in its own loop with a pump & filtering & cooling system. Application of turbo-timer after engine shutoff or shutdown to keep oil flowing into the hot turbo to help it cool off without burning the oil inside the turbo housing due to high temperatures present after extended operation.
3. Intercooler applied to cool boost pressurized intake air charge to produce a cooler fuel air mixture for enhance energy density of the load & reduction in knock risk or pre-detonation. Air or water source intercoolers can also make use of the vehicles AC system for enhance cooling.
4. Advanced materials turbo-charger making use of zirconia turbine impeller or other high strength ceramic like tungsten carbide impeller to ultra long life near zero erosion maintenance of the turbine blade structure.
5. Helium pressurized bearing for the ultimate aerospace grade application where low drag desired that oil cannot produce. A separate helium cooling & recovery system needed to avoid helium waste & such systems are extremely costly & typically only used in military drones & micro module nuclear reactors also utilized by nation state aerospace & defense applications.
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