Franisco

In 1998, Toyota's D4 direct injection system first appeared on various Japanese market vehicles equipped with the SZ and NZ engines. Toyota later introduced its D4 system to European markets with the 1AZ-FSE engine found in the 2001 Avensis and US markets in 2005 with the 3GR-FSE engine found in the Lexus GS 300. Toyota's 2GR-FSE V6 uses a more advanced direct injection system, which combines both direct and indirect injection using two fuel injectors per cylinder, a traditional port fuel injector (low pressure) and a direct fuel injector (high pressure).
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I understand that direct injection is supposed to make new strides in terms of efficiency and power. But what is it that makes direct injection so much "better" than port injection?
> Direct injection would mean you can calculate the exact amount of fuel to inject into each cylinder but i was under the impression
> that port injection would allow a more even air/fuel mixture since the turbulence from the intake manafold would help mix the air/fuel
> like a carburator would (crappy analogy i know)
>> With direct injection, you can delay putting fuel in till you've compressed most of the air and then create a burning wave front in >> the droplets as injected. This gives a more even burn.
>> Also with direct injection you can control the spray more accurately than relyign on swirl in the inlet ports. I saw some research >> on direct injection years ago and they used innovate chamber design to pre-mix the diret injection and create the near perfect
>> burn. I'm not aware that any of this is done in todays DI's