What is the working principle of the four-wheel drive system in the older Tucson model?
2 Answers
The working principle of the four-wheel drive system in the older Tucson model involves the use of a limited-slip differential to distribute the drive ratio between the front and rear wheels. It takes a portion of the power currently allocated to the front wheels and redistributes it to the rear wheels through this differential, creating a four-wheel drive mode. Below are several types of four-wheel drive systems: Part-time four-wheel drive: Part-time four-wheel drive is a system where the driver can manually switch between two-wheel drive and four-wheel drive. By engaging or disengaging the transfer case based on driving needs, the system achieves either two-wheel or four-wheel drive. This is the most common four-wheel drive system found in off-road vehicles or SUVs with four-wheel drive capabilities. On-demand four-wheel drive: On-demand four-wheel drive is a system that only activates four-wheel drive when necessary, otherwise operating in two-wheel drive. This system not only reduces the cost of manufacturing four-wheel drive vehicles but also provides better fuel economy for users. Mainstream production SUVs like the Honda CR-V and Toyota RAV-4 are equipped with on-demand four-wheel drive systems. Full-time four-wheel drive: Full-time four-wheel drive means that all wheels are independently driven at all times while the vehicle is in motion. Full-time four-wheel drive vehicles offer superior driving fundamentals compared to two-wheel drive vehicles: better power, traction, enhanced driving experience, increased safety during aggressive driving, and more stable handling. Therefore, this system is typically found in high-end SUVs such as the Audi Q7, BMW X5, and Mercedes-Benz GL.
I remember when I drove the old Tucson, the 4WD would kick in and be a huge help every time I hit snow or muddy roads. Simply put, it wasn’t always in four-wheel drive mode—on dry roads, it mainly ran on the front wheels to save fuel. But when the system detected a wheel slipping—like when the front wheels lost traction on wet grass—it would automatically send power to the rear wheels. This was controlled by a small computer underneath the car, managing a multi-plate clutch: when sensors detected slip, the computer would increase clutch pressure to transfer power from the engine to the rear axle. The process was quick, taking less than a second. During daily commutes, you wouldn’t notice it, but in poor road conditions, it made the car much more stable. I even tried manually locking the 4WD mode for more reliability when off-roading in the mountains. Overall, it worked well, but during maintenance, you’d want to check if the sensors were aging.
