Automatic Transmission/Transaxle: Description and Operation
GENERAL DESCRIPTION
The automatic transmission comes in two models, R4A51 and V4A51.
TRANSMISSION
The transmission includes the torque converter and the gear train. A 3-element, 1 -step, 2-phase torque converter with built-in torque converter clutch is incorporated. The gear train of the V4A51 transmission consists 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.
This transmissions is the newly developed 4-speed automatic transmission that merges advanced electronic technology and mechanical technology. A hydraulic balance mechanism is incorporated for the transmission clutch, allowing for ultra-high speed gearchanges.
The weight has been reduced by using precision sheet metal pressing of the clutch retainer, etc., and using aluminum die cast for the oil pump housing.
HYDRAULIC CIRCUITS
TRANSMISSION CONFIGURATION DRAWING
FUNCTION ELEMENT TABLE
* Item marked with an * operate only when stopped [approximately 10 km/h (6.2 mph) or less].
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, and "Adaptive Shift Control", which 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 driver's style.
Adaptive Shift Control During Acceleration
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 up-shifts 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 more powerful response.
Adaptive Shift Control On Downgrades
3. If the computer determines that the driver tends to apply the brakes often on a descending roadway, it adjusts timing to shift down sooner so that the engine brake is more effectively applied. Conversely, if the computer determines that the driver does not brake much while driving downhill, it delays downshifting to limit the effect of the engine brake.
SYSTEM CONSTRUCTION DIAGRAM
SHIFT PATTERN CONTROL
<3.0L Engine> UPSHIFT PATTERN
<3.0L Engine> DOWNSHIFT PATTERN
<3.0L Engine> HOLD MODE PATTERN
<3.5 Engine> UPSHIFT PATTERN
<3.5 Engine> DOWNSHIFT PATTERN
<3.5 Engine> HOLD MODE PATTERN