AUTOMATIC TRANSMISSION SYSTEM

Line Pressure Control

• In order to obtain predetermined line pressure characteristics in accordance with each sensor signal, the ECM activates the shift solenoid valve SLT (line pressure control solenoid assembly) to regulate the throttle pressure.

• This makes it possible for the primary regulator valve to precisely and minutely control the line pressure in accordance with the engine output, thus providing smoother shift characteristics.

Clutch Pressure Optimal Control

• The ECM monitors the signals from various types of sensors, such as the transmission revolution sensor (NT), allowing shift solenoid valve SL1 and shift solenoid valve SLT (line pressure control solenoid assembly) to minutely control the clutch pressure in accordance with engine output and driving conditions. As a result, smooth shift characteristics are achieved.

Clutch to Clutch Pressure Control

• This control is used for shifting from 5th to 6th gear and from 6th to 5th gear.

• The ECM actuates shift solenoid valves SL1 and SL2 in accordance with various signals. The output from these shift solenoid valves acts directly on control valves B2 and C3 in order to regulate the line pressure that acts on the B2 brake and C3 clutch.

• High response and excellent shift characteristics have been achieved.

Orifice Switching Control

• At extremely low temperatures, the ATF viscosity increases (becomes thick), making the oil pump susceptible to cavitation. For this reason, the orifice switching control reduces the volume of ATF in the hydraulic circuit and increases the volume of ATF drawn by the oil pump, in order to prevent the oil pump from cavitating.

• While stopped in the 1st gear, the ECM turns off the shift solenoid valve S1 and turns on (normally off) the shift solenoid valve S4 in order to apply the line pressure to the 1-2 shift valve and the SL1 relay valve. The 1-2 shift valve and the SL1 relay valve close the ATF passage for the secondary pressure from the secondary regulator valve, thus causing the secondary pressure to pass through orifice A. As a result, the volume of ATF in the hydraulic circuit is reduced.

• While stopped in a gear other than 1st, the secondary pressure from the secondary regulator valve travels through either or both of the 1-2 shift valve and SL1 relay valve, and passes through orifice B and C. As a result, the volume of the ATF in the hydraulic circuit is not reduced.

Powertrain Cooperative Control

• Driving Response and Acceleration Management System (DRAMS) is used for this vehicle. This system integrally controls the engine, transmission and other driving related controls. By integrally controlling the engine and automatic transmission using this system, quick response and a high quality driving feel in accordance with the driver's intentions are achieved, such as when accelerating or decelerating or during gear shifts.

1. Throttle Control at Launch

   
   

   • The engine output is optimally controlled with Electronic Throttle Control System-intelligent (ETCS-i) in real-time in accordance with the transient force from the torque converter when the vehicle is launched. This achieves a "suppressed sense of lurching forward", "tire slippage suppression" and "improved responsiveness", ensuring excellent launch performance.

   

2. Deceleration Force Control

   
   

   • The ECM determines the gear position when the accelerator pedal is off (released completely) in accordance with the way the accelerator pedal is released (suddenly or slowly) during deceleration. In this way, unnecessary upshifts and downshifts are prevented when the accelerator pedal is off and subsequent smooth acceleration is ensured, matching the driver's intentions.

   

3. Transient Shifting Control

   
   

   • Through integrated control with Electronic Throttle Control System-intelligent (ETCS-i), Electronic Spark Advance (ESA), and electronic control of the engagement and release speed of clutch and brake hydraulic pressures, excellent response and shift shock reduction have been achieved.

   

4. Engine Torque Control

   
   

   • Engine torque control used during gear shifts has been added to the cooperative control of the engine torque control and clutch hydraulic pressure control performed during gear shifts. This enhances gear engagement characteristics during gear shifts and achieves smooth gear changes.

   

Coast Downshift Control

• The ECM performs downshift control to prevent the engine speed from decreasing, thus keeping fuel cut control operating for as long as possible. In this way, the fuel economy is improved.

• For this control, when the vehicle is in 6th gear and starts decelerating, the transmission downshifts from 6th to 5th and from 5th to 4th before fuel cut control ends so that fuel cut control continues operating.

Multi-mode Transmission

• The driver can select the desired gear range by moving the shift lever to "+" (forward) or to "-" (backward) while the shift lever is in M. Also, the shift paddle switch (transmission shift switch assembly) can be used to change the gear range while the driver is holding the steering wheel. Thus, the driver is able to shift gears with a manual-like feel.

• When the vehicle is being driven at a prescribed speed or higher, any attempt to shift to a lower range by operating the shift lever will not be executed, in order to protect the automatic transmission. In this case, the ECM sounds the multi buzzer in the combination meter assembly twice to alert the driver.

• When the shift lever is in D, the driver can momentarily select a desired shift range by operating the shift paddle switch (transmission shift switch assembly). Automatic shifting will be reinstated under the following conditions:

  - The vehicle has stopped.

  - The driver continues to push the shift paddle switch (transmission shift switch assembly) in the "+" direction longer than 1 second.

  - The driver depresses the accelerator pedal longer than a predetermined length of time.

• When the shift lever is in M, the gear hold control, lock-up control, high response upshift control and blipping downshift control are used in order to improve response in accordance with the driver's operation of the accelerator pedal, shift lever or shift paddle switch (transmission shift switch assembly), and to improve gear shift feeling.

1. Gear Hold Control

   
   

   • Gear shifting will not be performed under gear hold control as long as the shift lever or shift paddle switch (transmission shift switch assembly) is not operated. This makes it possible to make efficient use of highest engine speeds. However, in the following cases, operation of gear hold control is limited.

   Automatic shifting when the shift lever is in M

   When the ATF or engine coolant temperature is low, gear shifting will be performed automatically. When the ATF temperature is high, gear shifting will be performed automatically.

2. Lock-up Control

   
   

   • While the shift lever is in M, lock-up control operates from 4th gear, transmitting the changes in engine power directly to the output shaft, the same way as with a manual transmission, and thus, direct response to the accelerator operation is achieved.

3. High Response Upshift Control

   
   

   • The high response upshift control achieves highly responsive upshift operation using the clutch to clutch pressure control, which regulates each clutch and brake quickly and precisely, and by the powertrain cooperative control, which optimally regulates engine torque during shifting.

   

4. Blipping Downshift Control

   
   

   • The blipping downshift control regulates each clutch and brake using the clutch to clutch pressure control, allowing them to be engaged smoothly and disengaged quickly. In addition, fuel injection volume is increased and engine speed is boosted by the powertrain cooperative control, thus ensuring engine brake force. In this way, a smooth and quick downshift is achieved.

   

Flex Lock-up Clutch Control

• In the low-to-mid-speed range, this flex lock-up clutch control regulates the shift solenoid valve SLU (lock up control solenoid assembly) to provide an intermediate mode between the on and off operations of the lock-up clutch in order to improve the energy transmitting efficiency. As a result, the operating range of the lock-up clutch has been increased and fuel economy has been improved.

Neutral Control

• Neutral control is used to disengage the transmission from the engine while the vehicle is stopped.

• When the shift lever is in D and the vehicle is stopped, the ECM semi-disengages the forword clutch and the brake. This reduces the load on the engine and improves fuel economy while the vehicle is stopped.

Artificial Intelligence Shift Control (AI-shift Control)

• The AI-shift control determines optimal transmission control based on input signals and automatically changes the shift pattern. As a result, a high caliber of transmission operation is achieved.

• The AI-shift control includes a road condition support control and a driver's intention support.

• The AI-shift control is effected with the shift lever in D, based on the accelerator pedal and brake operation data. The AI-shift control will be canceled when the shift lever is moved to a position other than D.

1. Road Condition Support Control

   
   

   • The ECM identifies the throttle valve opening angle, accelerator pedal opening angle and vehicle speed to determine whether the vehicle is being driven uphill or downhill. Unnecessary upshift is restrained to automatically achieve optimal drive force at all times while driving uphill. Downshift is automatically conducted to achieve optimal engine brake force, while driving downhill.

   

2. Driver's Intention Support Control

   
   

   • The driver's intention support control is estimated based on the accelerator pedal operation, vehicle condition and a shift pattern that is well-suited to the driver's intention is selected without operating the switch.

   
   

   • When the drive mode (SPORT*1, SPORT S*2 or SPORT S+*2) is selected, the driver's intention is assumed even when in the automatic shifting mode, thus enabling a dynamic drive.

   
   

   • By actively utilizing the low gear range to suppress unnecessary shifting, an improvement in the vehicle stability and acceleration performance has been achieved.

   Tech Tips

   *1: Except F SPORT

   *2: For F SPORT

   

Drive Mode Select Function

• The drive mode can be selected by operating the drive mode select or SNOW switch.

• The selected drive mode will be shown on the multi-information display in the combination meter assembly.

• The drive characteristics of each drive mode are as follows:

Figure 1. Combination Switch Assembly (The illustration is a representative example.)

*A	Except Models for G.C.C. Countries	-	-
*1	Drive Mode Select	*2	SNOW Switch
*3	Combination Switch Assembly	-	-

Figure 2. Optitron Meter (The illustration is a representative example.)

*A	Except Models for G.C.C. Countries	-	-
*1	Multi-information Display	*2	SNOW Mode Indicator Light
*3	Drive Mode Indicator Light	-	-

Figure 3. TFT LCD Meter

*A	Except Models for G.C.C. Countries	-	-
*1	Multi-information Display	*2	SNOW Mode Indicator Light
*3	Drive Mode Indicator Light	-	-

Gear Shift Indicator System

• Gear shift indicator system is a system to promote upshifting to the fuel-efficient and optimalgear ranges in accordance with the driving conditions such as the accelerator pedal opening andthe vehicle speed, etc. when the vehicle is running while the shift lever is in M.

• By driving in accordance with the upshifting recommendations indicated by the gear shift indicator in the multi-information display, the driver can enhance environmental performance, improve fuel economy and reduce exhaust gas output within the limits of engine performance.

Figure 4. Optitron Meter

*1	Multi-information Display	*2	Gear Shift Indicator Light "-" (backward)
*3	Gear Shift Indicator Light "+" (forward)	-	-

Figure 5. TFT LCD Meter

*1	Multi-information Display	*2	Gear Shift Indicator Light "-" (backward)
*3	Gear Shift Indicator Light "+" (forward)	-	-