Editing Stratified charge engine (section)

== TFSI engines ==
'''Turbo fuel stratified injection''' ('''TFSI''') is a trademark of the [[Volkswagen Group]] for a type of forced-aspiration ("[[turbocharger|turbo]]") engine where the fuel is pressure-injected straight into the [[combustion chamber]] in such a way as to create a stratified charge. FSI  [[Gasoline direct injection|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.<ref>{{cite web|url=http://www.audi.co.uk/audi/uk/en2/tools/glossary/engine_driveline/fsi.html |title=Audi UK > Glossary > Engine & Driveline > FSI® |access-date=July 24, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090428151335/http://www.audi.co.uk/audi/uk/en2/tools/glossary/engine_driveline/fsi.html |archive-date=April 28, 2009 }}</ref>

===Advantages===
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

===Disadvantages===
# 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 engines (like [[Toyota Dynamic Force engine|Toyota's Dynamic Force engines]]) 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 [[Gasoline direct injection|direct injection]])<ref>{{Cite web|url=http://products.bosch-mobility-solutions.com/en/de/powertrain/powertrain_systems_for_passenger_cars_1/direct_gasoline_injection/direct_gasoline_injection_23.html|title = Bosch Mobility Solutions}}</ref>