System Description [08/2014 - ]

1. The dynamic radar cruise control system has two cruise control modes: constant speed control mode and vehicle-to-vehicle distance control mode.
   • Vehicle-to-vehicle distance control mode is selected by default when the dynamic radar cruise control system is turned on using the cruise control switch (ON-OFF button).
   • Operation of constant speed control mode is the same as that for a conventional cruise control system.
2. This system maintains the vehicle at the speed that the driver has set, as long as there are no vehicles ahead. In addition to this, the system maintains the vehicle-to-vehicle distance that has been set by the driver. If the system detects a vehicle driving at a slower speed ahead while the driver is driving at a constant speed, it controls the engine to decelerate the vehicle. If further deceleration is required, the system controls the brake actuator in order to apply the brakes. Thereafter, if there are no vehicles ahead within the set vehicle-to-vehicle distance because either the vehicle ahead or the driver has changed lanes, the system accelerates slowly to reach the set speed and resumes driving at this speed.
3. Constant speed control mode is designed to maintain a constant vehicle speed. Vehicle-to-vehicle distance control mode is designed to control vehicle speed and vehicle-to-vehicle distance using the constant speed function, deceleration cruising function, follow-up cruising function, and acceleration cruising function.
4. The millimeter wave radar sensor assembly and the driving support ECU assembly control the system while vehicle-to-vehicle distance control mode is operating, and send signals to each actuator and ECU.
5. In vehicle-to-vehicle distance control mode, the dynamic radar cruise control system receives signals from the yaw rate sensor and the steering angle sensor. Based on these signals, the system then estimates curve radius and compensates for information on the preceding vehicle while turning. It can also compensate using brake control when approaching another vehicle.
6. This system judges the presence of a vehicle in front and the distance to it based on the signals from the radar sensor while vehicle-to-vehicle distance control mode is operating. Using this information, the system informs the driver of danger with the warning buzzer, performs brake control, and turns on the stop lights when approaching a vehicle in front.
7. The following illustration shows a control example under the following conditions: own vehicle speed is 100 km/h (62 mph) and the speed of the vehicle in front is 80 km/h (50 mph). The vehicle distance can be set to any of the following 3 distances by operating the distance control switch (distance control switch): long (approximately 50 m (164 ft.)), middle (approximately 40 m (131 ft.)), and short (approximately 30 m (98 ft.)) when the vehicle speed is approximately 80 km/h (50 mph).
   Fig 1: Dynamic Radar Cruise Control System Control Example

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT: 

   • Vehicle distance increases and decreases in accordance with vehicle speed.
   • Control conditions are indicated on the cruise control part of the combination meter assembly.

1. Low speed limit

   The lowest possible set speed is approximately 40 km/h (25 mph). The cruise control system cannot be set when the vehicle speed is below the low speed limit. Control of vehicle speed will be automatically canceled but the stored vehicle speed will be retained when the vehicle speed drops below the low speed limit while the cruise control is controlling vehicle speed.

2. High speed limit (constant speed control mode)

   The highest possible set speed is approximately 200 km/h (124 mph). The cruise control system will be set at the high speed limit when the cruise control is set and the vehicle speed is over the high speed limit. Also, +/RES cannot be used to increase the speed beyond the high speed limit.

3. High speed limit (vehicle-to-vehicle distance control mode)

   The highest possible set speed is approximately 170 km/h (106 mph). The cruise control system will be set at the high speed limit when the cruise control is set and the vehicle speed is over the high speed limit. Also, +/RES cannot be used to increase the speed beyond the high speed limit.

The cruise control switch is used to turn the cruise control system on and off, as well as operate 8 functions: SET, - (COAST), TAP-DOWN, RES (RESUME), + (ACCEL), TAP-UP, CANCEL, and MODE. The SET, TAP-DOWN, and - (COAST) functions, and the RES (RESUME), TAP-UP, and + (ACCEL) functions are operated with the same switch. The cruise control switch is an automatic return type switch which turns on only while operating it in the direction of each arrow and turns off after releasing it. The dynamic radar cruise control system has two cruise control modes: constant speed control mode and vehicle-to-vehicle distance control mode.

• Vehicle-to-vehicle distance control mode is selected by default when the dynamic radar cruise control system is turned on using the cruise control switch (ON-OFF button). (The cruise control indicator light and "RADAR READY" indicator come on.)
  Fig 2: Identifying Multi-Information Display And Cruise Main Indicator Light

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  TEXT IN ILLUSTRATION
  
  

  *1	Cruise Control Indicator Light (Vehicle-to-vehicle distance control mode)
  *2	Multi-information Display

• Operation of constant speed control mode is the same as that for a conventional cruise control system.

1. MODE CONTROL

   Pushing the switch to MODE for more than 1 second while vehicle-to-vehicle distance control mode is ready switches the cruise control system to constant speed control mode.

2. SET CONTROL (Constant speed control mode)
   Fig 3: Setting Constant Speed Control Mode

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   The vehicle speed is stored and constant speed control mode begins controlling vehicle speed when the cruise control switch is pushed to -/SET while driving with the cruise control system on, and the vehicle speed is over the low speed limit after entering constant speed control mode. The cruise control set indicator light will come on, and the set speed will be displayed in the multi-information display.

   TEXT IN ILLUSTRATION
   
   

   *1	Cruise Control Indicator Light (Constant speed control mode)
   *2	Cruise Control SET Indicator Light
   *3	Multi-information Display

3. SET CONTROL (Vehicle-to-vehicle distance control mode)
   Fig 4: Setting Vehicle-To-Vehicle Distance Control Mode

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   The vehicle speed is stored and vehicle-to-vehicle distance control mode begins controlling vehicle speed when the cruise control switch is pushed to -/SET while driving with the cruise control system on, and the vehicle speed is over the low speed limit. The cruise control SET indicator light will come on, and the set speed will be displayed in the multi-information display.

   TEXT IN ILLUSTRATION
   
   

   *1	Cruise Control Indicator Light (Vehicle-to-vehicle distance control mode)
   *2	Cruise Control SET Indicator Light
   *3	Multi-information Display

4. - (COAST) CONTROL (Constant speed control mode)

   When the cruise control switch is held to - SET while the cruise control system is operating, the ECM sends a "throttle valve opening angle 0°" demand signal to the cruise control system. Then the vehicle speed, when the cruise control switch is released, is stored and maintained.

5. - (COAST) CONTROL (Vehicle-to-vehicle distance control mode)

   When vehicle-to-vehicle distance control mode is controlling vehicle speed and the cruise control switch is pushed to -/SET and held in that position, the stored vehicle speed decreases by approximately 5 km/h or 5 mph.

6. TAP-DOWN (CONTROL) (Constant speed control mode)

   When constant speed control mode is controlling vehicle speed and the cruise control switch is tapped to the -/SET side (for 0.6 seconds or less), the stored vehicle speed decreases by approximately 1.6 km/h (1 mph) for each time the switch is tapped. When the cruise control switch is released from -/SET and the difference between the current and stored vehicle speed is more than approximately 5 km/h (3 mph), the current vehicle speed is stored and maintained.

7. TAP-DOWN CONTROL (Vehicle-to-vehicle distance control mode)

   When vehicle-to-vehicle distance control mode is controlling vehicle speed and the cruise control switch is tapped to the -/SET side (for 0.6 seconds or less), the stored vehicle speed decreases by approximately 1 km/h or 1 mph for each time the switch is tapped.

8. + (ACCEL) CONTROL (Constant speed control mode)

   sensor and motor is instructed by the ECM to open the throttle valve when + RES on the cruise control switch is pressed and held while the constant speed control mode is in operation. When the cruise control switch is released from + RES, the vehicle speed is stored and constant speed control is maintained.

9. + (ACCEL) CONTROL (Vehicle-to-vehicle distance control mode)

   When vehicle-to-vehicle distance control mode is controlling vehicle speed and the cruise control switch is pushed to +/RES and held in that position, the stored vehicle speed increases by approximately 5 km/h or 5 mph. Pushing the cruise control switch to +/RES while following a vehicle using vehicle-to-vehicle distance control mode does not increase actual vehicle speed, but changes only the set speed.

10. TAP-UP CONTROL (Constant speed control mode)

    When constant speed control mode is controlling vehicle speed and the cruise control switch is tapped to the +/RES side (for 0.6 seconds or less), the stored vehicle speed increases by approximately 1.6 km/h (1 mph) for each time the switch is tapped. When the cruise control switch is released from +/RES and the difference between the current and stored vehicle speed is more than approximately 5 km/h (3 mph), the stored vehicle speed will not be changed.

11. TAP-UP CONTROL (Vehicle-to-vehicle distance control mode)

    When vehicle-to-vehicle distance control mode is controlling vehicle speed and the cruise control switch is tapped to the +/RES side (for 0.6 seconds or less), the stored vehicle speed increases by approximately 1 km/h or 1 mph for each time the switch is tapped.

12. MANUAL CANCEL CONTROL

    Performing any of the following cancels cruise control system control of vehicle speed (the stored vehicle speed in the driving support ECU assembly is maintained).

    • Depressing the brake pedal
    • Moving the shift lever from D or S to any other position
    • Selecting the 3rd, 2nd, or 1st range with the shift lever in S
    • Pulling the cruise control switch to CANCEL
    • Turning the cruise control system off using the cruise control switch (ON-OFF button) (The stored vehicle speed in the ECM is not maintained.)
13. RES (RESUME) CONTROL

    If control of vehicle speed by the cruise control system was canceled by the stop light switch, CANCEL switch, or shift lever operation, and if vehicle speed is between the low and high speed limits, pushing the cruise control switch to +/RES restores and maintains the stored vehicle speed from the time of cancellation. In constant speed control mode, once the vehicle speed drops below the low speed limit, RESUME operation is possible after accelerating past the low speed limit and pushing the cruise control switch to +/RES.

The driving support ECU assembly determines the distance to the vehicle in front, relative speed, target speed reduction, and deceleration rate. Based on this data, the ECU transmits a brake demand signal to the skid control ECU via the ECM.

While the dynamic radar cruise control system is operating, the transmission may downshift from an overdrive gear on an uphill road. After the downshift, if the system determines that the uphill inclination has become smaller based on the throttle valve opening angle, the transmission automatically returns to the overdrive gear.

This system has an automatic cancellation function (fail-safe). Refer to FAIL-SAFE CHART [08/2014 - ] .