01
Electronically Controlled Automatic Transmission (ECAT)
Generally speaking, there is a significant difference between the speed and torque required by the driving wheels of a vehicle and what the engine can provide. Therefore, a transmission system is needed to adjust the transmission ratio from the engine to the driving wheels, transmitting the engine's power to the driving wheels to accommodate changes in external load and road conditions. Additionally, parking and reversing rely on the transmission system to function, coordinating the working conditions of the engine and transmission system to fully utilise the potential of the power transmission system and achieve optimal matching. This is the fundamental task of the transmission control system.
ECAT can automatically change the position of the gear lever by calculating and judging various parameters controlled by the driver, such as engine load, speed, vehicle speed, and brake status. It precisely controls the transmission ratio according to the shift characteristics, thereby achieving optimal control of the transmission shift, obtaining the best gear position and shift timing. This device has advantages such as high transmission efficiency, low fuel consumption, good shifting comfort, good driving stability, and long transmission life. Using electronic technology, especially microelectronic technology, to control the transmission system has become the main method for realising automatic transmission functions in modern vehicles.
02
Electronically Controlled Four-Wheel Drive Technology (4WD)
The driving force of a vehicle comes from the tyre’s adhesion to the ground. Four-wheel drive makes full use of the wheel’s adhesion to the ground, naturally resulting in better driving performance. However, due to the different turning radii of the wheels during steering, the wheels rotate at different speeds (inner and outer, front and rear), so the four wheels cannot be connected by a rigid transmission system. Differentials must be set between the left and right wheels and between the front and rear drive shafts. The issue is that the driving force of the four wheels is limited by the wheel with the least friction with the ground, necessitating the addition of a differential lock. Electronically controlled four-wheel drive technology uses sensors to perceive the condition of the four wheels on the road surface, analyses and judges through a microcomputer, and drives the system via solenoid valves to change the characteristics of the viscous coupler, distributing the driving force between the front and rear drive shafts and the left and right wheels.
3. Brake Control System
01
Anti-lock Braking System (ABS)
ABS detects the speed of each wheel through speed sensors installed on each wheel or drive shaft, calculates the wheel slip rate, compares it with the ideal slip rate, and decides to increase or decrease the brake pressure accordingly. The actuating mechanism adjusts the brake pressure in time to keep the wheel in an ideal braking state, maintaining a rolling state with slight slip and preventing lock-up. This has become a standard configuration for modern passenger cars.
02
Electronic Brakeforce Distribution (EBD)
When braking, if the adhesion conditions of the four tyres to the ground are different, the friction between the four wheels and the ground will differ. If the braking force of the four wheels is the same, it can easily cause skidding, tilting, and rollover. EBD’s function is to calculate the friction force values caused by different adhesion conditions of the four tyres at the moment of braking and adjust the braking devices accordingly. It performs high-speed adjustments during movement according to the set program to match the braking force with the friction force (traction force), ensuring vehicle stability and safety. This system, in conjunction with ABS, can greatly improve braking performance.
03
Anti-Slip Regulation (ASR)
ASR is an extension and enhancement of the anti-lock braking system, sharing many components with ABS. It uses speed sensors on the driving wheels to detect wheel slip. When slip occurs, the control unit reduces the speed by braking or by reducing throttle input to prevent further slipping. Essentially, it is a speed regulator that improves the longitudinal adhesion between the wheels and the road surface during sudden speed changes when starting or cornering, providing optimal driving force and increasing safety while maintaining directional stability.
04
Electronic Stability Programme (ESP)
ESP is an anti-skid system that can identify unstable vehicle conditions and compensates for vehicle skidding by controlling the braking system, engine management system, and transmission management system, preventing the vehicle from skidding off the road. Other similar systems from different manufacturers include Nissan’s Vehicle Dynamic Control (VDC), Toyota’s Vehicle Stability Control (VSC), Honda’s Vehicle Stability Assist (VSA), and BMW’s Dynamic Stability Control (DSC).
05
Electronic Parking Brake (EPB)
EPB integrates the functions of temporary braking during driving and long-term braking after parking, achieving parking brake control through electronic means. The working principle is similar to mechanical parking brakes, both using a cable to tighten the rear brake shoes for braking. Another type uses electromechanical callipers, generating braking force through an electric motor clamping the brake pads. EPB extends from basic parking functions to automatic parking functions (AUTO HOLD). The use of automatic parking technology allows the driver to avoid prolonged braking when the vehicle is stationary and prevents unnecessary rolling when the electronic parking brake is activated, effectively preventing the vehicle from rolling back.
4. Steering Control System
01
Electric Power Steering (EPS)
When the steering wheel is operated, a torque sensor installed on the steering shaft continuously measures the torque signal on the steering shaft. This signal, along with the vehicle speed signal, is input to the Electronic Control Unit (ECU). The ECU determines the magnitude and direction of the assist torque based on these input signals. The motor torque is reduced and increased by the electromagnetic clutch through the reduction mechanism and applied to the steering mechanism of the car, providing a steering force that matches the vehicle’s operating conditions.
02
Electronically Controlled Four-Wheel Steering (4WS)
When a vehicle is steered, due to lateral forces, the front wheels exhibit understeering characteristics, and the rear wheels tend to oversteer. The latter can cause a loss of steering stability, especially at higher speeds, possibly resulting in side skidding and rollover. The solution generally involves compensating by turning the rear wheels in the same direction as the front wheels by 1° to 2°. Electronically controlled four-wheel steering technology uses sensors to perceive the front wheel speed, steering angle, and vehicle body yaw. The data is processed by a microcomputer and the rear wheels are steered by a servo motor, with response times in milliseconds.
5. Driving Control System
01
Adaptive Suspension System (ASS)
The adaptive suspension system can automatically and timely adjust the damping characteristics and spring stiffness of the suspension according to the instantaneous load, maintaining the predetermined height of the suspension. This greatly improves the vehicle’s stability, handling, and riding comfort.
02
Cruise Control System (CCS)
Cruise Control, also known as speed control system, allows the driver to maintain a fixed pre-set speed without operating the accelerator pedal. It can be used during long-distance driving, reducing the need for the driver to frequently press the accelerator. The speed control device automatically adjusts the throttle opening according to driving resistance to maintain a constant speed. If the vehicle speed tends to drop during uphill driving, the microcomputer control system automatically increases the throttle opening; during downhill driving, it automatically decreases the throttle opening to adjust the engine power. When the driver shifts to a lower gear or brakes, the control system automatically disengages. This system reduces driver fatigue during long-distance driving and provides convenience while also improving fuel economy.
03
Tyre Pressure Monitoring System (TPMS)
This system automatically detects the tyre pressure and temperature and provides an alarm for any tyre abnormalities. The system can be divided into two types: indirect TPMS, which judges tyre abnormalities through the rotational speed difference of the tyres, and direct TPMS, which uses tyre pressure monitoring sensors installed inside the tyres to monitor tyre pressure and temperature in real time during both stationary and driving conditions. It provides timely alarms for high pressure, low pressure, and high temperature conditions, preventing traffic accidents caused by tyre faults and ensuring driving safety.
6. Safety Electronic Control System
01
Supplemental Restraint System (SRS)
This system is a common passive safety device on vehicles worldwide. In the event of a collision, the electronic control components trigger the nitrogen compound in the airbags located in the steering wheel centre (sometimes in the dashboard or glovebox) to rapidly burn and generate nitrogen gas, instantly inflating the airbags. The airbags form a cushioning pad between the driver and the steering wheel or between the front seat passengers and the dashboard, preventing injuries from hard impacts. This device must be used in conjunction with seat belts to be effective.
02
Collision Warning and Avoidance System (CWAS)
This system has multiple forms. Some systems automatically warn the driver when the distance between two vehicles decreases to a safety threshold, and if the vehicles continue to move closer, the system automatically controls the brakes to stop the car just before a collision. Other systems display the distance to obstacles behind the car when reversing, effectively preventing reversing accidents.
7. Comfort Electronic Control System
01
Automatic Air Conditioning System
Automatic Temperature Control (ATC), commonly known as automatic climate control, automatically maintains the cabin temperature at a preset value once the target temperature is set. The automatic air conditioning system consists of a refrigeration system, heating system, ventilation system, automatic control system, and air purification system. The fully automatic temperature control system includes temperature sensors, a control system ECU, and actuating mechanisms. The temperature sensors include external air temperature sensors, internal air temperature sensors, solar sensors (sunlight intensity sensors), and evaporator temperature sensors.
02
Automatic Seat Adjustment System (AAS)
This system combines ergonomics and electronic control technology. It uses sensors to perceive the posture of the occupant and adjusts the seat position to suit the occupant's comfort requirements.
03
Adaptive Front-lighting System (AFS)
The adaptive front-lighting system adjusts the low beam