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System Description

  1. GENERAL 
    1. The dynamic laser cruise control system has two cruise control modes: the constant speed control mode and vehicle-to-vehicle distance control mode.
      • The vehicle-to-vehicle distance control mode is always selected when starting the dynamic laser cruise control system.
      • Operation of the constant speed control mode is the same as that for a conventional cruise control system.
    2. This system maintains the vehicle running at the speed that the driver has set, as long as there are no vehicles ahead in the same lane. Then, the system maintains the 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 decelerates the vehicle speed by hybrid vehicle control. 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 vehicle speed and resumes driving at the constant speed.
    3. The constant speed control mode is designed to maintain a constant cruising speed. The vehicle-to-vehicle distance control mode is designed to control cruising at a constant speed function, deceleration cruising function, follow-up cruising function and acceleration cruising function.
    4. The laser sensor and the distance control ECU (cruise control ECU) control the system while the vehicle-to-vehicle distance control mode is in operation, and send signals to each actuator and ECU.
    5. In vehicle-to-vehicle distance control mode, the dynamic laser cruise control system receives signals from the yaw rate (deceleration sensor) and the steering angle sensor. Based on these signals, it then estimates curve radius and compensates for information on the preceding vehicle while turning. It can also compensate for the 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 laser sensor while the vehicle-to-vehicle distance control mode is in operation. Using this information, the system informs the driver of any danger with the warning buzzer, performs brake control, and turns on the stop light when approaching the 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). Setting of the vehicle distance can be changed to 3 distances by operating the distance control switch (distance control switch): long (approximately 75 m (246 ft)), middle (approximately 50 m (164 ft)), and short (approximately 30 m (98 ft)) when the vehicle speed is approximately 90 km/h (55 mph).
      Fig 1: Identifying Conditions For Control
      G05140619Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      • Vehicle distance increases and decreases in accordance with vehicle speed.
      • Controlling condition is indicated on the multi-information display in the combination meter.
  2. FUNCTION OF MAIN COMPONENTS 
    COMPONENTS FUNCTION CHART

    Item Outline
    Laser Sensor Radiates laser rays forward, uses the reflected rays for detecting the presence of a vehicle being driven ahead, the vehicle-to-vehicle distance, and the relative speed, and transmits these pieces of information to the distance control ECU.
    Distance Control ECU Determines which vehicle to follow based on the information provided by the laser sensor, calculates the target acceleration signals for following the vehicle, and transmits an acceleration/deceleration request, warning buzzer request and brake request to the hybrid vehicle control ECU.
    Cruise Control Switch Main Switch Turns ON/OFF the power to the system.
    Control Switch
    • The vehicle speed setting, deceleration setting, resuming a preset speed, acceleration setting, and canceling signals are output to the hybrid vehicle control ECU through the operation of this switch.
    • Changing the control mode, the constant speed control mode and vehicle-to-vehicle distance control mode.
    Distance Control Switch While the vehicle is being driven in the follow-up cruising control, the vehicle-to-vehicle distance can be switched in three stages to long, middle, or short by pulling the switch.
    Hybrid Vehicle Control ECU Calculates the target engine speed and required engine motive force in accordance with the signals from the switches, sensors, and ECUs, in order to activate the ETCS-i (Electronic Throttle Control System intelligent).
    Skid Control ECU
    • Actuates the brake actuator in accordance with the brake control request received from the distance control ECU via the hybrid vehicle control ECU. At this time, the skid control ECU drives the stop light relay and lights up the stop light.
    • Sounds the buzzer in accordance with the warning buzzer request received from the distance control ECU via the hybrid vehicle control ECU.
    Stop Light Switch Detects the pressing of the brake pedal by the driver and transmits its signal to the hybrid vehicle control ECU.
    Vehicle Speed Sensor Transmits the vehicle speed to the hybrid vehicle control ECU.
    Throttle Control Motor Adjust the throttle valve to the target opening in accordance with the signals received from the hybrid vehicle control ECU.
    Steering Angle Sensor Detects the amount and direction of steering and outputs a steering angle signal to the skid control ECU.
    Yaw Rate and Deceleration Rate Sensor Detects the yaw rate of the vehicle.
    Warning Buzzer Sounds when the distance to the vehicle driven ahead is reduced. The skid control ECU outputs a signal to sound the buzzer.
    Combination Meter Meter ECU
    • The multi-information display displays the control conditions of the system.
    • Flashes the displays simultaneously with the sounding of the warning buzzer.
    Cruise MAIN Indicator Light
    • Illuminates when the MAIN switch is ON.
    • Illuminates when the system control is in operation.
    • Flashes when there is a malfunction in the system.
    Master Warning Light Illuminates when there is a malfunction in the system.
    Multi-information Display Indicates the state of system control by the meter ECU.
    Wiper Control Switch Transmits the wiper control switch condition information to the distance control ECU.
    Brake Actuator Actuates the brakes in accordance with the signals from the skid control ECU.
  3. LIMIT CONTROL 
    1. Low speed limit

      The lowest possible limit of the speed setting range is set at approximately 43 km/h (27 mph). The cruise control system cannot be set when the driving vehicle speed is below the low speed limit. Cruise control operation will be automatically canceled and the stored vehicle speed will be erased when the vehicle speed decreases below the low speed limit (40 km/h (25 mph)) while the cruise control is in operation.

    2. High speed limit (constant speed control mode) The highest possible limit of the speed setting range is set at approximately 200 km/h (125 mph). The cruise control system cannot be set when the driving vehicle speed is over the high speed limit. Also, RESUME/ACCEL cannot be used to increase speed beyond the high speed limit.
    3. High speed limit (vehicle-to-vehicle distance control mode)

      The highest possible limit of the speed setting range is set at approximately 85 mph (USA) or 135 km/h (CANADA).

  4. CRUISE CONTROL OPERATION 

    The cruise control main switch operates 8 functions: SET, COAST, TAP-DOWN, RESUME, ACCEL, TAP-UP, CANCEL, and MODE. The SET, TAP-DOWN and COAST functions, and the RESUME, TAP-UP and ACCEL functions are operated with the same switch. The cruise control main switch assembly is an automatic return type switch which turns on only while operating it in each arrow direction and turns off after releasing it. The dynamic laser cruise control system has two cruise control modes: the constant speed control mode and vehicle-to-vehicle distance control mode.

    • The vehicle-to-vehicle distance control mode is always selected when starting up the dynamic laser cruise control system.
    • Operation of the 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 driving with the cruise control main switch ON-OFF button on (RADAR READY is on) switches the mode to the constant speed control mode.

    2. SET CONTROL (Constant speed control mode)

      Vehicle speed is stored and constant speed control is maintained when pushing the switch to -/SET while driving with the vehicle speed within the set speed range (between the low and high speed limits) after pushing the cruise control main switch ON (RADAR READY is on), and entering the constant speed control mode.

    3. SET CONTROL (Vehicle-to-vehicle distance control mode)

      Vehicle speed is stored and vehicle-to-vehicle control is maintained when pushing the switch to -/ SET while driving with the cruise control main switch ON (RADAR READY is on), and vehicle speed is within the set speed range (between the low and high speed limits).

    4. COAST CONTROL (Constant speed control mode)

      When the cruise control main switch is set to -/SET and held in that position while the cruise control system is operating, the hybrid vehicle control ECU sends a "Cruise request opening angle 0°" demand signal to the cruise control system. Then the vehicle speed, when the cruise control main switch is released, is stored and maintained.

      HINT:

      An actual throttle valve opening angle of 0° is not possible due to the idle speed control, etc.

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

      When -/SET on the cruise control main switch is pressed and held while the vehicle-to-vehicle distance control mode is in operation, the stored vehicle speed decreases by approximately 5 km/h (CANADA) or 5 mph (USA) per second.

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

      When tapping down the cruise control main switch to -/SET (for approximately 0.5 seconds) while the constant speed control mode is in operation, the stored vehicle speed decreases each time by approximately 1.6 km/h (1 mph). When the cruise control main switch is released from -/SET and the difference between the driving and stored vehicle speed is more than 5 km/h (3 mph), the vehicle speed is stored and constant speed control is maintained.

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

      When tapping down the cruise control main switch to -/SET (for approximately 0.5 seconds) while the vehicle-to-vehicle distance control mode is in operation, the stored vehicle speed decreases each time by approximately 5 km/h (CANADA) or 5 mph (USA).

    8. ACCELERATION CONTROL (Constant speed control mode)

      The throttle valve motor of the throttle position sensor and motor is instructed by the hybrid vehicle control ECU to increase the vehicle speed when +/ RES on the cruise control main switch is pressed and held while the constant speed control mode is in operation. When the cruise control main switch is released from +/RES, the vehicle speed is stored and constant speed control is maintained.

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

      When +/RES on the cruise control main switch is pressed and held while the vehicle-to-vehicle distance control mode is in operation, the stored vehicle speed increases by approximately 5 km/h (CANADA) or 5 mph (USA) per second. Pushing the cruise control main switch to +/RES while following the vehicle in front with the vehicle-to-vehicle distance control mode does not increase the actual vehicle speed, but changes only the set vehicle speed.

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

      When tapping up the cruise control main switch to +/ RES (approximately 0.5 seconds) while the constant speed control mode is in operation, the stored vehicle speed increases each time by approximately 1.6 km/h (1 mph). However, when the difference between the driving and the stored vehicle speeds is more than 5 km/h (3 mph), the stored vehicle speed will not be changed.

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

      When tapping up the cruise control main switch to +/ RES (for approximately 0.5 seconds) while the vehicle-to-vehicle distance control mode is in operation, the stored vehicle speed increases each time by approximately 5 km/h (CANADA) or 5 mph (USA).

    12. MANUAL CANCEL CONTROL

      Performing any of the following cancels the cruise control system while it is in operation (the stored vehicle speed in the hybrid vehicle control ECU is maintained).

      • Depressing the brake pedal
      • Moving the shift lever to any position except D
      • Pushing the cruise control main switch to CANCEL
      • Turning the cruise control main switch OFF (the stored vehicle speed in the hybrid vehicle control ECU is not maintained).
    13. RESUME CONTROL

      If the cruise control operation was canceled with the stop light switch or the CANCEL switch, and if driving speed is within the set speed range, pushing the cruise control main switch to +/RES restores the vehicle speed memorized at the time of cancellation, and maintains constant speed control.

  5. BRAKE CONTROL 

    When the vehicle is approaching a vehicle ahead at high relative speed, deceleration cruising control decelerates the vehicle by hybrid vehicle control. If an even greater deceleration rate is necessary, the brake control mode is used to apply the brakes to further reduce the speed. When there is a significant increase in the vehicle speed after the brake control has ended, such as when the vehicle is descending a sharp hill, the hybrid vehicle control system reduces the speed at a rate that is equivalent to the B range, in order to maintain the proper distance from the vehicle ahead.

    If the distance control ECU has determined that it is necessary to effect brake control, it decides on the target speed, and the speed of the own vehicle. Then, the distance control ECU transmits a brake control request signal via the hybrid control ECU to the skid controls ECU. The skid control ECU then controls the brake actuator to apply the brakes. While the brakes are being applied, the stoplight illuminates to warn the drivers of following vehicles.

  6. AUTO CANCEL (FAIL-SAFE) 

    This system has an automatic cancellation function (failsafe) (for details, CC-59).

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