What are ABC, ABD, ABS, ASR, BAS, DAC, DSC, EBA, EBD, EDS, ESP? Today we will provide a comprehensive explanation—-■ What is ABC?
ABC is the Active Body Control system. The ABC system allows for quicker and more precise control of a car’s roll, pitch, yaw, bounce, and body height. With reduced body roll and minimal changes in wheel camber, the tires can maintain better contact with the ground, enhancing tire grip and maximizing the driving and braking performance. The introduction of ABC overcomes the conflict between comfort and handling in suspension settings, closely aligning with consumer demands in these areas.■ What is ABD?
ABD is the Automatic Braking Differential. It is a new product in the braking system, primarily designed to shorten braking distances, and works in conjunction with ABS, EBD, and others. During emergency braking, the car tends to pitch forward, shifting weight to the front wheels, which can severely reduce the load on the rear wheels, potentially causing them to lose grip. In this scenario, only the front wheels may be braking, resulting in extended stopping distances. ABD effectively prevents this situation by detecting the speed of all wheels and reducing the braking force on the rear wheels to maintain effective friction with the ground while maximizing the braking force on the front wheels to shorten stopping distances. The difference between ABD and ABS is that ABS ensures wheels do not lock during emergency braking for safety and control, but does not effectively shorten braking distances. In contrast, ABD allows maximum braking force while ensuring the vehicle does not skid, thus effectively shortening stopping distances.■ What is ABS?
ABS is the Anti-Lock Brake System. Without ABS, emergency braking can lead to wheel lock-up, resulting in longer stopping distances due to sliding friction between the tires and the ground. If the front wheels lock, the vehicle loses lateral steering control and may drift; if the rear wheels lock, they lose lateral grip, leading to potential fishtailing. This is especially true on snow-covered surfaces during emergency stops. ABS controls brake fluid pressure to prevent wheel lock-up, operating in a cycle of locking and releasing to keep the vehicle in a state of critical slip.However, in some movie stunt scenes, cars may not be equipped with ABS, allowing for sliding and fishtailing effects. Enthusiast drivers often prefer not to install ABS for a more thrilling experience. Ultimately, ABS is designed for general drivers to ensure their safety. In the 1990s, ABS became a major focus in car configurations, and while it was not mandatory in every vehicle, it is now standard equipment in new cars.■ What is ASR?
ASR is the Acceleration Slip Regulation system. As the name suggests, it prevents the drive wheels from slipping during acceleration, especially in high-power vehicles, to maintain stability and control. Its principle is straightforward: when the computer detects a drive wheel slipping, it reduces engine power and applies brakes to the slipping wheel until normal rotation is restored. Regardless of how advanced a car is, it only has a limited contact area with the ground, which is the surface area of its four tires. If wheel slip is not controlled, the vehicle can lose control. It is essential to recognize that slip can be dangerous not only during braking but also during acceleration.■ What is BAS?
BAS is the Brake Assist System. In emergencies, 90% of drivers lack decisiveness when applying brakes. The Brake Assist System is designed to address this issue by detecting the speed at which the driver presses the brake pedal. If the driver quickly presses the brake pedal but does not apply sufficient force, the system assists and increases braking force to the maximum within less than one second, shortening stopping distances in emergencies.■ What is DAC?
DAC is the Down-hill Assist Control system. Similar to engine braking, to prevent excessive load on the braking system and reduce driver burden, the down-hill assist control activates when the transfer case is in the L position; at speeds of 5-25 km/h with the DAC switch turned on, the vehicle can automatically control speed at an appropriate level without pressing the accelerator or brake pedals. The system activates the parking lights while in operation.■ What is DSC?
DSC is the Dynamic Stability Control system. Developed by BMW, the DSC system integrates ASC (Automatic Stability Control) and traction control, allowing for selective braking of slipping drive wheels to stabilize the vehicle. On icy, sandy, or gravel surfaces, the driver can activate DTC mode with a button to enhance traction. Additionally, the DSC system’s slightly delayed intervention response increases vehicle traction and driving force, providing an extraordinary driving experience. Another function of the DSC is the CBC (Cornering Brake Control) system, which eliminates oversteering tendencies by controlling asymmetric braking during slight turns.■ What is HAC?
HAC is the Hill-start Assist Control system. Using a Hall-effect speed sensor, it can detect both vehicle speed and rotor rotation direction with high sensitivity (detecting at 0 km/h). When in gear and the vehicle begins to roll backward (due to insufficient drive force on an incline), this system automatically applies braking force to the wheels, releasing it when the wheels move forward again. This system helps improve safety when driving on inclines.■ What is HDC?
HDC is the Hill Descent Control system. It actively senses the slope and road conditions, automatically controlling traction, braking force, and speed to maintain control while moving forward or backward, allowing the driver to focus solely on steering through difficult terrain. The HDC system maintains optimal speed control on steep slopes, making off-road driving easier and safer for novice drivers.■ What is EBA?
EBA is the Electronic Brake Assist. Under normal circumstances, most drivers apply minimal force when starting to brake and then increase it based on the situation. If a sudden, much larger braking force is required, or if the driver reacts too slowly, this approach can hinder timely maximum braking. Many drivers are also unprepared for the need to apply significant braking force or react too late. EBA understands braking behavior based on the rate at which the driver presses the brake pedal. If it detects a panic increase in brake pressure, EBA activates maximum braking force within milliseconds, much faster than most drivers can respond. EBA significantly shortens emergency stopping distances and helps prevent rear-end collisions in stop-and-go traffic. The EBA system monitors the brake pedal’s motion. Once it detects a rapid increase in brake pedal pressure and the driver continues to apply significant force, it releases stored hydraulic pressure of 180 bar to apply maximum braking force. Once the driver releases the brake pedal, the EBA system returns to standby mode. By applying maximum braking force earlier, the emergency brake assist significantly shortens stopping distances.■ What is EBD?
EBD is the Electronic Brake-force Distribution system. When braking, if the four tires have different levels of traction with the ground (e.g., one tire on a slippery surface and another on a dry surface), the friction between the tires and the ground differs, leading to potential skidding, tilting, or rollover. EBD’s function is to rapidly calculate the friction values of all four tires during braking and adjust the braking system to ensure proper matching of braking force and traction, ensuring smooth and safe vehicle operation.
During emergency braking, EBD balances the effective ground grip of each wheel before ABS engages, preventing fishtailing and lateral drift while shortening stopping distances. EBD effectively enhances ABS performance, making it a complementary function. Currently, many domestic models, such as the Honda Odyssey, Palio, and Siena, indicate “ABS+EBD” in their braking systems.■ What is EDS?
EDS is the Electronic Differential Lock system. It is an extension of ABS, used to identify whether a wheel has lost traction, thus controlling acceleration slip. Vehicles equipped with EDS can utilize ground traction better than regular vehicles, especially on inclined surfaces. However, it has a speed limitation and only activates when speed is below 40 km/h, mainly to prevent slipping during starts and low-speed maneuvers.■ What is ESP?
ESP is the Electronic Stability Program. This system typically supports the functions of ABS and ASR (Traction Control System). It analyzes vehicle state information from various sensors and sends corrective commands to ABS and ASR to help maintain dynamic balance. ESP helps vehicles maintain optimal stability under various conditions, especially during oversteering or understeering scenarios.
ESP generally requires the installation of steering sensors, wheel sensors, side slip sensors, and lateral acceleration sensors. It monitors the vehicle’s state and automatically applies braking force to one or more wheels to keep the vehicle on its intended path, even applying brakes up to 150 times per second in certain situations. Currently, there are three types of ESP: a four-channel system that applies braking force independently to all four wheels; a two-channel system that applies braking force independently to the front wheels; and a three-channel system that applies braking force independently to the front wheels while simultaneously applying to the rear wheels.
The most important feature of ESP is its proactive nature; while ABS reacts passively, ESP can prevent problems before they occur.■ What is TCS?
TCS is the Traction Control System, also known as the Traction Control System. Its function is to detect the limit of tire grip and automatically reduce or cut off power to the slipping wheel to maintain traction. When braking on slippery surfaces, wheels may slip, potentially leading to loss of steering control. Similarly, during starts or rapid acceleration, drive wheels may slip, especially on icy surfaces, posing a danger. TCS is designed to address this issue. TCS uses electronic sensors to detect when the driven wheel’s speed is lower than that of the driven wheel (a characteristic of slipping) and sends a signal to adjust ignition timing, reduce throttle, or apply brakes to the slipping wheel, preventing further slip. TCS improves vehicle stability, acceleration, and climbing ability. Initially installed only in luxury vehicles, TCS is now common in many standard cars. When used in conjunction with ABS, TCS further enhances vehicle safety. TCS and ABS can share wheel speed sensors and connect to the vehicle’s computer to continuously monitor wheel speeds. If slipping is detected at low speeds, TCS immediately triggers ABS to reduce that wheel’s slip. If slipping is detected at high speeds, TCS sends a command to the computer to reduce engine speed or downshift to prevent wheel slip and maintain vehicle control.
TCS is a sophisticated electronic system, but its nature is to constrain drivers to drive conservatively, rather than allowing them to fully exploit the vehicle’s performance limits, making it less suitable for sports cars.■ What is GPS?
GPS is the Global Positioning System. GPS is based on 24 satellites that provide three-dimensional positioning and speed information globally, around the clock. The positioning principle involves the user receiving signals from satellites and calculating the distance, clock correction, and atmospheric correction parameters to determine their position. Currently, civilian GPS can achieve positioning accuracy within 10 meters. The unique capabilities of GPS have attracted attention in the automotive industry. After the U.S. opened part of the GPS system post-Gulf War, the automotive industry quickly seized the opportunity to develop navigation systems, enabling vehicle positioning and directional display, which were rapidly deployed.
