Automatic Transmission/Transaxle: Description and Operation
The A/T come in two models, namely, F4A42 and F4A51.
TRANSAXLE
The transaxle is configured of the torque converter and gear train. A 3-element, 1-step, 2-phase torque converter with built-in torque converter clutch is incorporated. The gear train is configured of three sets of multi-plate clutches, two sets of multi-plate brakes, one set of one-way clutches and two sets of planetary gears configured of the sun gears, carriers, pinion gears and annulus gears.
This automatic transaxle is made up of the following main parts.
The torque converter employs a 3 element, 1 step, 2 phase lock-up clutch.
The gear train is made up of 3 multi-plate clutches, 2 multi-plate brakes and 2 planetary gears made up of a sun gear, carrier, pinion gear and annulus gear.
The cases consist of a converter housing, transaxle case, rear cover and a valve body cover.
Parts related to oil pressure regulation are the oil pump, which pressurizes the oil; the regulator, which controls the pressure setting; the solenoid valve, which changes the oil pressure with electrical signals; the pressure control valve, which controls the oil pressure coming from the solenoid valve that effects each clutch and brake; each kind of valve, which carry out the retention of the oil pressure through the lines; and finally the valve body, which houses all the valves.
HYDRAULIC CIRCUIT
FUNCTION ELEMENT TABLE
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 Neutral 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
<2.4L Engine> UPSHIFT PATTERN
<2.4L Engine> DOWNSHIFT PATTERN
<3.0L Engine> UPSHIFT PATTERN
<3.0L Engine> DOWNSHIFT PATTERN