V6 w/Atkinson but no DFI

2 messages, Last post on Jun 30, 2009 at 1:30 PM

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What is this discussion about? Lexus RX 450h, Fuel Efficiency (MPG), SUV

#1 of 2 V6 w/Atkinson but no DFI by wwest Jun 15, 2009 (8:03 am)
Strange, Lexus solved the V6 Atkinson problem but yet didn't adopt DFI. Intake manifold/plenum now called a "surge tank". Larger air intake volume/area, "surge tank" to help "absorb" the V6's reverse airflow problems with the Atkinson cycle. And at low RPM they use extended range VVT-i to run the engine in standard Otto mode. 12.5:1 static AND dynamic compression ratio whereas the Prius I4 with less reverse airflow runs 13:1. Both engines transition to Atkinson cycle only when/if the cylinder charge begins to reach the level that detonation might otherwise result. Altogether a neat idea and yet another way to suppress the reverse airflow pulses of the V6 at low engine RPM. Wonder what the intake "noise", RUMBLE, is like...?? DFI would have allowed a CR increase to 15-16:1 for the Prius' I4 and maybe 15:1 for the V6. Maybe next year..??
#2 of 2 New RX350 F/awd for RX450h FWD. by wwest Jun 30, 2009 (1:30 pm)
Does anyone know or have any idea if the 2010 RX350's rear wheel drive system, PTO, diff'l, etc, could be easily adapted to/for the 2010 FWD RX450h..?? It sure would be nice to have a RWD RX450h with F/awd as a once-in-awhile wintertime option.