Turbo fuel stratified injection
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Turbo fuel stratified injection (TFSI) is a trademark of the Volkswagen Group for a type of forced-aspiration ("turbo") engine where the fuel is pressure-injected straight into the combustion chamber in such a way as to create a stratified charge. FSI direct injection technology increases the torque and power of spark-ignition engines, makes them as much as 15 percent more economical and reduces exhaust emissions.
Some advantages of TFSI engines:
- Better fuel distribution and better fuel charge inside the combustion chamber
- During the injection process the fuel gets evaporated, cooling the cylinder chamber
- Cooling effect of the pressurized fuel allows for use of a lower octane fuel leading to a cost savings for the end user
- Higher compression ratios, which translates into more power
- Increased fuel combustion efficiency
- Higher power during pick-up of vehicle.
- Huge rise of number of emitted exhaust particles
- Carbon build up behind the intake valves. Since fuel is directly injected inside the combustion chamber, it never gets a chance to wash any contaminants behind the valves. This results in excessive carbon build up over time, hindering performance. Some cars (like the Toyota 2GR-FSE engine in the Lexus IS) combine direct injection with traditional multi port fuel injection to ameliorate this problem.
- More expensive - much higher pressure fuel pumps are required to inject the fuel directly into the cylinder. This requires fuel pressures of up to 200 bar, much greater than a traditional multiport injection setup. See direct injection.
- "Archived copy". Archived from the original on April 28, 2009. Retrieved July 24, 2009.
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