What is the principle of the Highlander E-Four four-wheel drive system?
3 Answers
The Highlander E-Four four-wheel drive system can be simply understood as connecting the front and rear wheels through a driveshaft, allowing all four wheels to receive the driving force distributed by the engine, thereby propelling the vehicle forward. Here are some additional details: 1. Advantages: For vehicles, the benefits of a four-wheel drive system are twofold. Firstly, it provides more comprehensive off-road capability and superior ability to escape difficult terrain. Secondly, it enhances the vehicle's handling and stability to a certain extent. 2. Part-time four-wheel drive: Part-time four-wheel drive is a system where the driver can manually choose between two-wheel drive and four-wheel drive. The driver can switch between two-wheel drive and four-wheel drive modes by engaging or disengaging the transfer case based on road conditions. This is the most common drive mode for off-road vehicles or four-wheel drive SUVs. Its characteristics include simple structure, high stability, and durability.
Driving this car for over a year, the E-Four all-wheel drive feels like a smart assistant. In city driving, it mainly operates as front-wheel drive, just as fuel-efficient as a two-wheel-drive car. But the moment the system detects front wheel slip—like when going through puddles on rainy days—the rear motor immediately kicks in. What's interesting is that this system doesn't use a traditional driveshaft; the rear wheels are powered solely by an independent motor. The Toyota hybrid system stores excess energy in the battery, which directly powers the rear wheels when needed. The most profound experience was navigating snowy curves—you can feel the computer dynamically adjusting front and rear power distribution, keeping the steering wheel exceptionally stable. This design reacts faster than mechanical all-wheel drive and saves the weight of a central differential.
The four-wheel drive system is ingeniously designed, with the focus on the three-motor layout. The engine and front motor drive the front axle, while the rear axle is equipped with a separate 40 kW motor. The computer monitors dozens of data points every second: throttle position, steering wheel angle, and wheel speed differences. If the front wheels start to slip, the rear motor can deliver 200 Nm of torque within 0.1 seconds. The most practical feature is the snow mode, where the system automatically distributes more power to the rear wheels, making it feel like an invisible hand is pushing your back when climbing hills. Compared to mechanical four-wheel drive, it's much more fuel-efficient—my daily commute consumes only 6 liters.
