On Vehicle Service

GENERAL DESCRIPTION





The automatic transmission comes in two models, R4A51 and V4A51.

TRANSMISSION
The transmission is made up of the torque converter and the gear train. A 3-element, 1-step, 2-phase torque converter with built-in torque converter clutch is used. The gear train of the V4A51 transmission made up of three sets of multiple disc clutches, two sets of multiple disc brakes, one set of one-way clutch and two sets of planetary carriers.





TRANSMISSION CONFIGURATION DRAWING





COMPONENTS AND FUNCTIONS





FUNCTION ELEMENT TABLE





SECTIONAL VIEW





SECTIONAL VIEW

ELECTRONICALLY-CONTROLLED SYSTEM

INVECS-II
^ When in drive ("D" range), the new automatic transmission employs an innovative shift schedule to provide a high level of comfort and "easy driving style" that matches all driving conditions as well as the driver's driving style.





^ INVECS-II features "Optimum Shift Control," which provides shift timing the average driver perceives to be the optimum timing under any road conditions "Adaptive Shift Control" adjusts shift timing to match the driving habits and preferences of individual drivers.

FEATURES

OPTIMUM SHIFT CONTROL





1. The shift patterns found satisfying by the typical driver for all ranges of driving are stored in the computer's memory. The computer uses this data to analyze road conditions and the driver's style of operation, and then outputs the optimal shift patterns stored in its memory to best match the conditions.





2. We introduce the latest in control technologies with an innovative new algorithm called the "neural network" that works to imitate the decision-making processes of the human brain. The neural network links a wide variety of input data regarding road and operating conditions, and instantly makes accurate shift control decisions.

ADAPTIVE SHIFT CONTROL
1. The computer learns the driving habits and preferences of each individual driver by processing driving data on engine output, tire load, foot brake operation, etc. It then uses this data to adjust shift timing to best suit the drivers style.





2. If the computer determines from the driving patterns that the driver is one who enjoys a relaxed, unhurried style, it adjusts timing to execute upshifts at a lower engine speed to provide a smooth, quiet ride. On the other hand, if the computer determines the driver to prefer a sporty ride, it adjusts timing to shift up at a higher engine speed to provide a more powerful response.





3. If the computer determines that the driver tends to apply the brakes often on a descending roadway, it adjusts timing to downshift sooner so that engine braking is more effectively applied. Conversely, if the computer determines that the driver does not brake much while driving downhill, it delays downshifting to minimize the effect of engine braking.





SYSTEM CONSTRUCTION DIAGRAM

SHIFT PATTERN CONTROL

<3.0L Engine> UPSHIFT PATTERN





NOTE: Within 2-to-3 and 3-to-4 movement ranges, the PCM adjusts shift points according to the driving conditions by memorizing the accelerator pedal stroke and braking timing.





DOWNSHIFT PATTERN

<3.5L Engine> UPSHIFT PATTERN





NOTE: Within 2-to-3 and 3-to-4 movement ranges, the PCM adjusts shift points according to the driving conditions by memorizing the accelerator pedal stroke and braking timing.





DOWNSHIFT PATTERN