Adaptive Cruise Control

DESCRIPTION 

Courtesy of CHRYSLER GROUP, LLC

The optional equipment intelligent Adaptive Cruise Control (ACC) system includes the following major components, which are described in further detail elsewhere in this service information:

• Adaptive Cruise Control (ACC) Module/DASM  - An ACC module is located on a bracket secured near the center of the underside of the front bumper behind the front fascia. Refer to STANDARD DRIVER ASSISTANCE SYSTEM, DESCRIPTION AND OPERATION .
• Antilock Brake System Module (ABS)  - An ABS module is located on the antilock brake Hydraulic Control Unit (HCU) in the engine compartment. Refer to MODULE, BRAKE SYSTEM CONTROL (BSCM), DESCRIPTION AND OPERATION .
• Brake Lamp Switch  - The brake (also known as stop) lamp switch is located on the brake pedal support bracket under the driver side of the instrument panel. Refer to LAMPS/LIGHTING - EXTERIOR, DESCRIPTION AND OPERATION .
• Instrument Panel Cluster (IPC)  - A CRUISE indicator is located in the fixed segment display of the IPC that provides an indication to the vehicle operator when the speed control system is turned ON. Refer to INSTRUMENT PANEL CLUSTER, DESCRIPTION AND OPERATION .
• Electronic Vehicle Information Center (EVIC)  - The EVIC is located in the IPC and provides an interface to the vehicle operator for setting the ACC customer preferences as well as a display of the adaptive speed control and Forward Collision Warning (FCW) system status messages. Refer to INSTRUMENT PANEL CLUSTER, DESCRIPTION AND OPERATION .
• Forward Facing Camera (FFC/HALF)  - The FFC/HALF is located inside the Combined Rear View Mirror Module (CRVMM) housing assembly. The FFC provides input for data fusion purposes allowing the ACC module data to be redundancy checked. Refer to STANDARD DRIVER ASSISTANCE SYSTEM, DESCRIPTION AND OPERATION .
• Powertrain Control Module  - The Powertrain Control Module (PCM) located in the right front corner of the engine compartment contains the software and hardware that monitors all of the speed control system inputs and controls all of the speed control system outputs. Refer to MODULE, POWERTRAIN CONTROL (PCM), DESCRIPTION AND OPERATION .
• Speed Control Switches/CSWC  - A speed control switch pod containing eight momentary switch push buttons (five standard cruise push buttons and three ACC push buttons) is located in the right horizontal spoke of the steering wheel. Refer to SWITCH, SPEED CONTROL, DESCRIPTION AND OPERATION .
• Steering Column Control Module (SCCM)/SWSM  - The SCCM is located at the top of the steering column just below the steering wheel.
• Wheel Speed Sensors  - A wheel speed sensor is located on the knuckle of each front and rear wheel.

OPERATION 

Quick Overview: 

• Utilizes an Intelligent Adaptive Cruise Control (iACC/DASM) module, the Traffic Sign Recognition system used in conjunction with the Forward Facing Camera (FFC/HALF) to identify vehicles in traffic, speed limit signs, vehicles forward path and maintains a selectable distance between the host vehicle and the vehicle in front of it.
• Speed limits are suggested to the driver. This come from the Traffic Sign Recognition system in which the Forward Facing Camera (FFC/HALF) recognizes road speed limit signs. Once the driver receives the speed suggestion, the driver can chose to set the sign speed limit as the speed target or reject the suggestion through the rocker switch.
• ACC with stop and go has full functionality between 0 and 100 mph.
• After ACC with stop and go brings the vehicle to a stop, the driver must indicate the intention to resume by either pressing the resume button or tapping the accelerator pedal.
• Driver can select one of four following distances depending on driver preference.

Preconditions for ACC operation:

• The system must be turned ON  .
• The engine must be running.
• The host vehicle is either moving forward or is in a standstill.
  • ACC with Stop and Go operates at 0 kph/mph
  • ACC with Follow to Stop: the minimum speed is 5 kph or higher
  • ACC base system speeds need to be 30 kph or higher
• The ESC must be present and not in a fault condition.
• The EPB must be preset for the ACC Stop and Go feature.
• Subject vehicle speed must be within operating parameters.
• Operational road types: urban and inter-urban roads; straight and curved roads with a road curvature radius equal to or less than 125 m; roads with positive or negative inclination transition (changes in road grade) up to 2%.
• Operational environment conditions: all weather conditions even if heavy rain and snow could reduce the performances of the system due to the conditions of the road surface. In any case the FFC/HALF and the ACC/DASM is operative unless there is a blockage to either components.
• Operational low-light conditions: the system performances and detection range are not affected by low light environments if the target vehicle(s) have their lights turned on.

Functional Overview -  The iACC system has functionality beyond that of Normal Cruise Control and Adaptive Cruise Control. This system has the functionality of the cruise control system of maintaining a driver defined Set Speed without the driver needing to press the throttle. This system also has the functionality of the regular ACC system of increasing and decreasing the vehicle speed based on target vehicles moving slower than the ACC Set Speed. Beyond the functionality of the regular ACC system, this system offers a larger operational speed range, which constitutes of speeds from 0 mph to a configurable upper bound. If a target vehicle comes to a standstill, the ACC system will also bring the ACC host vehicle to a stop, and will keep the vehicle at a standstill for an undetermined period of time by first applying the brakes, and after the brakes time-out, cancelling the ACC system and applying the Electronic Park Brake (EPB). The ACC with stop and go system will also incorporate Forward Collision Warning-Plus (FCW). With grade braking, the transmission will automatically downshift to maintain selected vehicle speed and distance, preventing overheating of brakes.

iACC uses the FFC/HALF in conjunction with the Traffic Sign Recognition system to detect road speed limit signs in either metric or imperial and supplies a customer with a suggested speed control setting. The customer has the option to concur or ignore the suggested settings by use of the rocker switch.

The ACC/DASM, FFC/HALF, ABS module, IPC, EVIC, PCM, SCCM and the BCM each contain a microcontroller and programming that allow them to communicate with each other using the Controller Area Network (CAN) data bus. This method of communication is used by the ACC module to provide inputs to the ABS module, the EVIC and the PCM. This is also is used by the ABS module to provide inputs to the PCM, by the SCCM to relay the status of the speed control switches to the PCM and by the PCM for control of the indicators in the IPC and the indications in the EVIC. Refer to COMMUNICATION, DESCRIPTION AND OPERATION .

The BCM is responsible for gateway data management for the entire systems in use for ACC and its variants.

The ACC with stop and go system used also incorporates grade braking and FCW. With grade braking, the transmission will automatically downshift to maintain selected vehicle speed and distance, preventing overheating of brakes.