Until now, only Ford was pushing this new Partial Throttle-by-Camshaft technology. However, an new system was introduced on the Chrysler Penta Star 3.6L V6 engine starting in 2011, but Chrysler doesn't really talk about it. The only clue you can find is low idle vacuum and the usage of the EVP (electric vacuum pump). It turns out Chrysler is using the ETC (electric throttle control) and the VVT (variable valve timing) both together at the same time to reduce cylinder pumping losses.
This is the way it supposed to work:
Instead of holding the engine at idle with a closed throttle plate, the VVT system is used to decrease the intake charge, lowering the effective compression of the engine. The ETC system can now hold the throttle plate a little bit further open without the engine speed increasing.
What you get is a low stable idle, but reducing the intake vacuum at idle decreases the amount of power wasted sucking against the closed throttle plate.
Please note: this system is NOT as aggressive as the Atkinson-cycled engine with no intake vacuum, but it a step in the right direction.
When testing this type of system, expect the MAP signal to be about 4-6Hg lower than normal. This also affects the Calculated Load PID, so you may notice some values over the 40% at idle.
This was submitted by Chrysler Certified Technician.
