AUTOMATIC TRANSMISSION SYSTEM

Driving Response and Acceleration Management System (DRAMS)

• A system for integrally controlling the motive force, which has been named the Driving Response and Acceleration Management System (DRAMS), is used. This system achieves a more optimal driving feel (including the vehicle behavior) by considering driver requests and the surrounding environment. It integrates controls for the engine, transmission and related systems, which form the base for the vehicle's motive force, to improve maneuverability and comfort.

• The Driving Response and Acceleration Management System (DRAMS), converts accelerator pedal operations into the motive force requested by the driver, judges the engine torque and gear position required to achieve that requested motive force, and integrally controls the engine and transmission. As a result, the motive force desired by the driver is generated, achieving a superior driving feel. In addition, DRAMS integrative control is performed according to the motive force requested by VDIM and the cruise control system, improving the control performance of the systems.

• High speed responsiveness according to the driver's intentions and a superior driving feeling are achieved even during a shift transition, start-off and deceleration.

  

1. Throttle Control at Launch

   
   

   • Electronic Throttle Control System-intelligent (ETCS-i) and cooperative control are used to optimally control the engine torque, improving the feeling of acceleration when initially depressing the accelerator pedal. As a result, responsive acceleration is achieved and high-quality start-off performance is made possible, suppressing feelings of lurching.

   • Sport mode*1 or Sport S/S+ mode*2 emphasize the responsiveness of control performed during reacceleration to achieve the motive force requested by the driver, improving driveability.

     *1: Models without AVS

     *2: Models with AVS

     

2. Control Helping Improve Fuel Efficiency and Quietness

   
   

   • When the accelerator pedal opening angle is low, control is performed to reduce the engine speed as much as possible and use the highly efficient range of the engine, helping improve fuel efficiency and quietness.

     

3. Drive Force Control Achieving Fuel Efficiency and Driveability

   
   

   • Motive force control provides the drive force of each shift position with a certain degree of freedom, achieving the motive force requested by the driver. In ranges where the accelerator pedal is only lightly depressed, the highly efficient range of the engine is proactively used to improve fuel efficiency performance. In addition, the difference in drive force between each gear position is minimized, achieving smooth shifting. On the other hand, in ranges where the accelerator pedal is heavily depressed, the motive force is generated according to changes in the engine speed, achieving a direct feeling of acceleration. As a result, fuel efficiency and driveability are achieved.

     

Direct Connected Downshift Control

• Direct connected downshift control is used to achieve linear engine speed changes during downshifting and smooth drive force changes that are linked with the engine speed.

• A 10-speed automatic transmission has wider gear ratios than an 8-speed automatic transmission. Therefore, the amount of time it takes until acceleration is felt when shifting at the same speed as an 8-speed automatic transmission is greater, such as when depressing the accelerator pedal to downshift from a higher gear to a lower gear. Also, in order to reduce the amount of time it takes until acceleration is felt, control is used to perform shifting in order. However, during that time, each time shifting is performed, the input shaft speed stalls and the amount of time required to reach the target gear increases. Therefore, high-precision oil pressure control and highly responsive shift solenoid valves are used to prevent stalls from occurring and directly connect each gear change, achieving smooth and highly responsive downshifting.

  Figure 1. Comparison of Same Shifting Speed

  

  Figure 2. Comparison when Shifting in Order

  

  Figure 3. Comparison during Direct Connected Downshifting Control

  

Coast Downshift Control

• Coast downshift control achieves low fuel consumption by performing fuel cut control as long as possible.

• When decelerating, flex lock-up clutch control and downshift control are performed to suppress decreases in the engine speed. As a result, the engine speed does not fall below the fuel cut recovery speed, allowing fuel cut control to be performed as long as possible.

  

Lock-up Timing Control

• Lock-up timing control is performed across a wider range to achieve direct drive force transmission and improved fuel efficiency performance.

• Lock-up timing control is performed when accelerating after decelerating and downshifting to achieve an extremely direct driving feel. In addition to using a torque converter, which uses a multi-plate lock-up clutch, the engine torque and oil pressure are optimally controlled to reduce shocks and improve responsiveness.

  

  Figure 4. Lock-up Timing Control Operation

  

  ○: Operates

  X: Does not operate

  -: Not applicable

1. Responsiveness during acceleration is improved by suppressing revving up of the engine speed to achieve a direct driving feel.

   

Flex Lock-up Clutch Control

• Fine-grained control of the drive force transmission distribution using a lock-up clutch (mechanical drive force transmission) and torque convertor (fluid drive force transmission) is performed according to driving conditions to dramatically improve the transmission efficiency.

• Flex lock-up timing control uses innovative feedback control logic to achieve higher dimensions of system stability and responsiveness in response to a variety of characteristic changes, etc.

  

  Figure 5. Flex Lock-up Timing Control Operation (Acceleration)

  

  ○: Operates

  X: Does not operate

  -: Not applicable

  Figure 6. Flex Lock-up Timing Control Operation (Deceleration)

  

  ○: Operates

  X: Does not operate

  -: Not applicable

Drive Mode Select

• This function automatically switches the powertrain control mode between the 5 types selected by drive mode select operations: "Eco", "Normal", "Power"*1 "Power1"*2 and "Power2"*2.

• SNOW Mode is used to assist driving on surfaces with low friction coefficients, such as snow-covered roads. Throttle characteristics are suppressed and starting off in 2nd gear is supported to suppress sudden drive force changes and ensure driving stability on snow-covered roads.*3

  *1: Models without AVS

  *2: Models with AVS

  *3: Except models for G.C.C. countries

  Models with AVS

  Drive Mode	Powertrain Control Mode	Outline
  Normal	Normal	Ensures fuel economy and driveability when driving in the city, but when driving on winding roads, selects the optimal gear position to provide a more enjoyable driving experience.
  Comfort
  Eco	Eco	Gradually adjusts the throttle characteristics to assist the driver with eco driving.
  Sport S	Power1	This mode is given the control characteristic of selecting a higher speed gear position than Normal mode. As a result, acceleration response and acceleration performance are improved and superior stability is ensured when driving around corners to provide a sportier driving feel when responsiveness and power are required, such as when driving on winding roads with many uphill slopes, downhill slopes and corners.
  Sport S+	Power2	Selects a higher speed gear position based on information from driver operations (accelerator and brake pedal operations, etc.) and road conditions (road grade, etc.). As a result, acceleration response and acceleration performance are dramatically improved and superior cornering performance is ensured when driving the vehicle at its limits, such as when driving on a race track.

  Models without AVS

  Drive Mode	Powertrain Control Mode	Outline
  Normal	Normal	Ensures fuel economy and driveability when driving in the city, but when driving on winding roads, selects the optimal gear position to provide a more enjoyable driving experience.
  Eco	Eco	Gradually adjusts the throttle characteristics to assist the driver with eco driving.
  Sport	Power	By changing the speed variation point of the transmission from NORMAL mode and controlling the throttle valve opening angle, acceleration and responsiveness are enhanced, supporting sporty driving. In addition, suspension control and steering control are integrated for switching to SPORT mode to improve driveability and stability without sacrificing passenger comfort. As a result, control is performed to enable operations based on the driver's intentions.

  

  *A	Except Models for G.C.C. Countries	*B	Models with AVS
  *C	Models without AVS	-	-
  *1	SNOW Switch (Satellite Switch Set)	*2	Drive Mode Select (Satellite Switch Set)

Artificial Intelligence-shift Control (AI-shift Control)

• AI-shift control, which automatically switches the shift pattern according to "road conditions" and the "driver's intentions", is used. AI-shift control is used in addition to the normal shift pattern, which takes into consideration the vehicle speed and the engine throttle opening angle as parameters to determine the shift position of the automatic transmission, achieving a higher dimension of comfortable driving.

  Tech Tips

  AI-shift control will be canceled when M mode or SNOW mode (Except models for G.C.C. countries) is selected.

  

1. Road Condition Support Control

   
   

   • Road condition support control judges whether the vehicle is traveling on an uphill or downhill slope according to information such as the throttle opening angle and vehicle speed. On uphill slopes, unnecessary upshifts are suppressed to constantly achieve the optimal amount of drive force, and on downhill slopes, downshifts are automatically performed to achieve the optimal engine brake force. However, when a paddle shift switch (transmission shift switch) operation is performed during AI-shift control, AI-shift control is canceled and D-range paddle active control is given priority.

     

2. Driver's Intention Support Control

   
   

   • Driver intention support control predicts the driver's intentions according to accelerator pedal operations and the vehicle condition and switches to a comfortable shift pattern that is appropriate for the driver without requiring any switch operations.

   
   

   1. Sudden Accelerator Pedal Release Control

   
   

   • When the accelerator pedal is released suddenly, this control makes it easier to hold the gear position, improving responsiveness when reaccelerating and the engine brake force.

     

   2. Downshifting Control during Hard Braking

   
   

   • High engine braking force and good re-acceleration response have been achieved by actively downshifting during deceleration when hard braking is made.

     

3. Driver Intention/Driving Scene Support Control

   
   

   • Driver intention/driving scene support control selects the optimal gear position according to the driver's intentions and the driving scene at that point in time.

   • When the driver is driving in a relaxed manner, a high gear position is selected to emphasize fuel efficiency.

   • When the driver is driving in a sporty manner, a low gear position is selected to emphasize drive force and responsiveness.

   • Even if the driver has the D range selected while sporty driving is performed on winding roads and race tracks, shifting is performed using a shift pattern that makes it feel like gear positions are being selected manually, achieving a high-speed responsive drive.

     Tech Tips

     Driver intention/driving scene support control will be canceled when Eco mode is selected.