Drive force control method for four-wheel drive vehicle

Abstract

A drive force control method for a four-wheel drive vehicle having front wheels as main drive wheels having a mechanism capable of adjusting a driving force distribution ratio between the front wheels and the rear wheels or a left and right driving force distribution ratio between the front wheels or the rear wheels. The transverse acceleration of vehicle is detected and the absolute value corresponding to the transverse acceleration is increased. The driving force distribution ratio between the front wheels and the rear wheels is controlled in way of increasing the distribution ratio of rear wheels and the left and right driving force distribution ratio between the front wheels or the rear wheels is controlled in way of increasing the driving force of a turning outer wheel. The control transverse acceleration is used in the control and obtained through correcting the transverse acceleration signal from a transverse acceleration sensor by using a presumed transverse acceleration calculated based on turning angle and vehicle speed. Thus the driving force distribution ratio between the front wheels and the rear wheels or a left and right driving force distribution ratio between the front wheels or the rear wheels can be reliably controlled by coordinating with the trend of the vehicle.

Description

technical field [0001] The invention relates to a driving force control method of a four-wheel drive vehicle. Background technique [0002] Conventionally, when a four-wheel drive vehicle is turning at a corner with a small turning radius in the four-wheel drive driving state in the low-to-medium speed range, the turning braking phenomenon occurs due to a difference in rotational speed due to the difference in turning radius between the front and rear wheels. [0003] As prior art for solving such a problem of the turning braking phenomenon, there are known front and rear wheel drive devices disclosed in JP-A-7-61779 and JP-A-7-64219. [0004] In the front and rear wheel drive device disclosed in the above publication, one of the front and rear wheels is used as the main drive wheel that receives power transmission directly from the power source, and the other side of the front and rear wheels is used as the slave drive wheel, and a driving wheel that can change the left and...

AI Technical Summary

Problems solved by technology

[0009] Making the load of each tire uniform is effective for improving the acceleration performance during cornering. However, in the prior art described in the above publication, there is no Regarding the description of making the ground contact load of each tire, that is, the load of each tire uniform, the fine driving force control is not disclosed in these publications.

For example, in the conventional driving force control method of the front and rear wheel drive devices, there is a problem that the actual movement of the vehicle body may not be sufficiently grasped depending on the state of the road surface.

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