Tuesday, July 10, 2012

Acura's new CVT Transmission Explained

CONTINUOUSLY VARIABLE TRANSMISSION
The ILX Hybrid features as standard a Continually Variable Transmission (CVT) – a first for
Acura. The CVT delivers excellent low-end acceleration matched with relaxed low-rpm cruising
along with offers smooth and predictable gear ratio transitions. By helping the engine and
electric motor operate in the most efficient range, the CVT provides a fuel efficiency benefit
superior to that of a conventional automatic transmission with fixed ratio gears. It also allows
for greater efficiency during regenerative braking by smoothing deceleration.

The transmission can be controlled by a straight-gate console-mounted shifter or via a steering
wheel paddle shifter system that works whenever the transmission is in either of its two
automatic modes. When the paddle shifters are used, the transmission offers a choice of
seven fixed ratios.

Automatic Modes
The transmission can be operated in two different fully automatic modes with the console mounted
straight-gate shifter. The D mode is ideal for most driving situations, and combines
fuel efficiency with smooth operation and responsive power when needed. The S mode is for
more performance-oriented driving, and features more aggressive transmission mapping to
keep engine rpm higher for greater acceleration and response.

Whether in D or S mode, special transmission logic programming allows the use of the steering-
wheel-mounted paddle shifters. When the driver operates the steering wheel-mounted
paddle shifters while in Drive, the transmission responds to the driver’s shift command by selecting
one of the available seven fixed ratios, and then returns to its normal fully automatic
Drive mode if further paddle shift inputs are not made within a short time. This special logic
makes it easy for the driver to command a quick downshift without leaving the convenience of
Drive mode.

S Mode
When in S mode, use of the paddle shifters puts the transmission into full manual mode that
remains until another mode of operation is selected with the console-mounted shifter. The
paddle shifters allow the driver to select among seven fixed gear ratios. When in manual
mode, if the engine redline is reached the ILX will automatically shift to the next gear ratio to
avoid engine damage. It will also shift down to an appropriate lower gear ratio if necessary.

L Mode
When the transmission is in S mode, simultaneously pressing and holding the upshift and
downshift paddles on the steering wheel places the transmission in L mode. In this mode, the
operation of the integrated electric motor is altered to increase the charge rate of the lithiumion
battery.

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