low oil pressure lexus LFA 2012 Technical Information / LEXUS 2012 LFA NURBURGRING PACKAGE GUIDE

33
Powertrain
LFA_Nurburgring_U
■Low friction internals
While the engine in the Nürburgring Package is the same engine model as the stan-
dard package, by meticulously adjusting items like the amount of oil supplied and the
friction surfaces of moving parts, a further reduction in friction has been achieved.
■Oil feed pump
In the standard engine, an inner relief system that circulates oil inside the oil feed pump
has been adopted. This restricts oil level fluctuations in the crankcase and oil pan,
achieving a reduction in friction and the occurrence of air bubbles in the oil.
Moreover, an exclusive pump was adopted for the cam timing adjusters (VVT-i). By
increasing the pressure of the oil supplied from the feed pump, the VVT-i can be oper-
ated even more effectively while the total amount of oil was reduced, thereby contrib-
uting to a reduction in total friction.
With the Nürburgring Package, the clearances inside the pump were optimized by
balancing the oil supply more precisely, further reducing friction.
■Piston rings
In the standard package's engine, linerless thermally sprayed bores were adopted for
the cylinder bore surface, simultaneously improving heat dissipation and reducing cyl-
inder bore distortion.
This accordingly made it possible to lower the tension of the top & second ring more
than that of a common mass-production engi ne and at the same time a thin 2-piece
nitride processed oil ring has been adopted, reducing friction losses.
Through the utilization of these aspects and optimized ring specifications, a further
reduction in friction has been achi eved in the Nürburgring Package.
LFA_Nur_J_U_K_M_OM77029U.book 33 ページ ２０１２年１月１７日　火曜日　午前１０時１３分

35
Powertrain
LFA_Nurburgring_U
In order to secure lubrication performance that could withstand high lateral accel-
eration, seven independent scavenger pumps were adopted and are located in
both sides of the cylinder head, the front and rear chain case and the crankcase,
pumping the collected engine oil into the air-cooled oil cooler and the oil tank.
Only the oil with a high temperature collected from the crankcase is pumped into
the air-cooled oil cooler, minimizing drops in pressure, which in turn reduces the
pump's driving loss.
The oil tank's construction achieves stable oil circulation even during high lateral
acceleration due to the adoption of a vertically long shape and specially designed
baffle plate.
Within the oil tank, cyclone type gas-liquid separation is performed and air bubbles
are removed from the collected oil. The oil is then sent to the lower part of the oil
tank and supplied to various parts of the engine via the feed pump which is located
on the same horizontal axis as the scavenger pump.
While a similar sequence of circulation is common with the standard package, it
plays a more important role in the Nürburgring Package, which pursues an even
higher level of driving performance.
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