Is an on-demand four-wheel drive system usually front-wheel drive or rear-wheel drive?
2 Answers
An on-demand four-wheel drive system is primarily rear-wheel drive under normal conditions, switching to four-wheel drive when appropriate, and generally operates in two-wheel drive mode. Additional information: 1. The on-demand four-wheel drive system can automatically switch between two-wheel drive and four-wheel drive modes based on the vehicle's driving conditions, without requiring manual intervention. 2. The drive wheels of a vehicle must be equipped with a differential to enable turning on the road, as the rotational speeds of the wheels differ during a turn. The differential can compensate for this speed difference. The full-time four-wheel drive mode is based on this concept, with its central differential allowing the vehicle to maintain four-wheel drive at all times. In contrast, part-time four-wheel drive systems lack a central differential and can only be manually switched to four-wheel drive mode during off-road conditions. Typically, they operate in two-wheel drive mode. Both full-time and part-time four-wheel drive systems have limitations in terms of widespread applicability, which led to the development of the on-demand four-wheel drive mode.
I've driven several part-time four-wheel-drive vehicles, like urban SUVs, and they mostly operate in front-wheel-drive mode during normal driving. Why? Mainly to save fuel, as four-wheel drive consumes more, so manufacturers set it up to primarily power the front wheels most of the time. On highways or flat city roads, you hardly feel the rear wheels moving. But it's different in special situations—like when the front wheels slip during rapid acceleration on rainy days, or when driving through mud or snow. Once the sensors detect slippage, the vehicle immediately distributes power to the rear wheels, becoming true four-wheel drive. Just remember, this isn't manually controlled; the car makes the decision entirely. So for everyday use, treating it as a front-wheel-drive vehicle is just right.