In driving force controlling apparatus and method for a four-wheel drive vehicle, a command is outputted to a front-and-rear wheel driving force distribution control system to reduce a clutch engagement force of a clutch, such as a frictional clutch, when a subtraction value of a detected value of a clutch transmission torque from that of a clutch input torque (Tinp - Tr) is smaller than a predetermined value (δ) and detected wheel velocities of both of left and right road wheels of the vehicle are substantially equal to each other (Vw1 ± α = Vw2 and Vw3 ± α = Vw4).

Driving force controlling apparatus and method for four-wheel drive vehicle

Energy consumption for any vehicle is described by energy balance (relationship between “energy in” and “energy out”), which consists of energy produced, energy consumed, internal losses as well as the need to overcome the inertia resistance to motion. Hybrid vehicles show big potential for further reduction in fuel consumption and exhaust gas emissions. Therefore, there is nothing strange in the fact that the hybrid cars are often identified as step on the journey to a more sustainable future. Currently, the powertrain concept allows synchronization of the operation of an ICE and an electric motor and redistribution of mechanical energy flows with the help of transmission shifts depending on the mode of operation of the hybrid powertrain (HPT). Different HPT control algorithms are applied in hybrid vehicle designs, however, the purpose of all of them is to: (i) minimize fuel consumption, (ii) minimize exhaust gas emission, (iii) minimize the system price, and (iv) ensure good vehicle control characteristics. This paper presents the novel algorithms suitable for real-time estimation of economic and ecological characteristics for the hybrid 2WD, 4WD, and High Mobility Multipurpose Wheeled Vehicle (HMMWV) vehicles moving under urban, extra-urban and off-road conditions.

Management of hybrid powertrain dynamics and energy consumption for 2WD, 4WD, and HMMWV vehicles

In a vehicle having an ABS control system, a braking control of a right and left rear wheels can be independently carried out when a lateral acceleration exceeds a lateral acceleration value set beforehand. When the ABS control is operated at one of the right and left rear wheels, the control system executes a stepwise pressure increase control which provides a stepwise pressure increase for the other rear wheel up to a braking pressure to be reached at a start of the control.

Braking force control system for vehicle

A brake control device that controls braking forces applied to wheels to stabilize the behavior of a vehicle turning a corner, and includes a turning condition detection unit detecting a turning condition of the vehicle; a braking amount setting unit setting braking amounts for the respective wheels based on the turning condition detected by the turning condition detection unit; a brake control unit applying braking forces to the wheels according to the braking amounts set by the braking amount setting unit; and a road surface friction coefficient estimation unit estimating a road surface friction coefficient of the road on which the vehicle is running. The braking amount setting unit changes upper limits of the braking amounts for the respective wheels according to the road surface friction coefficient when the vehicle is in a center differential lock mode or a direct four-wheel drive mode.

Braking control device for vehicle

Disclosed is a method for improving the handling characteristics of a vehicle while braking during cornering, comprising the following steps: detecting cornering and cornering direction; determining the rolling characteristics of individual wheels, optionally influencing the braking pressure of a brake on a wheel or several wheels according to the rolling characteristics of said wheels; checking the state of the vehicle to determine instabilities, and modifying braking pressure applied on at least one wheel when an instability is detected during a cornering maneuver extending for a time period exceeding a threshold time. Also disclosed is a device for improving handling characteristics while braking during cornering, comprising a detection device (320) for detecting a cornering maneuver and the direction of cornering, a determination device (302a-d) to determine the rolling characteristics of individual wheels (303a-d); an influencing device (309, 310) which optionally influences the braking pressure of the brakes (301a-d, 306a-d) on a wheel (303a-d) according to the rolling characteristics of said wheel (303a-d), a checking device (321) to check the state of the vehicle to determine instabilities, and a modification device (322) to modify the braking pressure of at lest one brake (301a-d, 306a-d) on a wheel (303a-d) when an instability is detected during a cornering maneuver extending for a time period exceeding a threshold time

Method and device for improving the handling characteristics of a vehicle while braking during cornering

A method is provided that provides optimum anti-skid control when the vehicle is turning. If a vehicle enters a turning motion, the maximum frictional resistance corresponds to a larger slip ratio; therefore, in this method, the slip threshold is gradually increased to provide the optimum anti-skid control.

Anti-skid control method

An anti-lock braking control system (ABS) has the slip of each wheel monitored and the slip ratio (lambda) of at least one of the front wheels measured. In a situation when this is greater than a preset threshold, the ABS action for each of the four wheels is initiated. If the ratio is less than the threshold, a special control procedure is applied to the rear wheels only.

Vehicle anti-lock braking control system (ABS)

PROBLEM TO BE SOLVED: To bring an estimated vehicle body speed close to an actual vehicle body speed by performing traction control while setting the estimated vehicle body speed to a wheel speed when fluctuation in the wheel speed due to application of a brake fluid pressure is the predetermined value or less. SOLUTION: A testing brake fluid pressure is impressed to a wheel cylinder 12 for wheels by an action of an open/close valve in a fluid pressure unit 20 for the predetermined time during traction control, and this impression is carried out to one wheel, and then, its wheel speed is found. It is determined whether the wheel grips or not by finding fluctuation in wheel speeds after/before application of a brake and a wheel acceleration. When the wheel grips, the fluctuation in the wheel speed and the wheel acceleration range within the predetermined values, and traction control is carried out while an estimated vehicle body speed is set to the wheel speed. In this way, the estimated vehicle body speed is brought close to an actual vehicle body speed, so that a speed reduction feeling or a lack of acceleration can be improved.

Traction controlling method and controller thereof

PROBLEM TO BE SOLVED: To improve the braking force and the stability by realizing the independent anti-lock brake control of each wheel when the slip ratio of at least one front wheel is larger than the prescribed value, and realizing the select low control of rear wheels when the slip ratio is smaller than the prescribed value. SOLUTION: The slip ratio λ of front wheels 15, 18 is measured by a wheel speed sensor 51 in realizing control by an anti-lock brake control device 1. The slip ratio may be either the mean value for both front wheels, or the value for any front wheel. The obtained slip ratio λ is compared with the prescribed slip ratio λt which is determined in advance, and when the obtained slip ratio λis larger, the anti-lock brake control of the wheel cylinder 14 is realized by an electronic control device 3 with four wheels, i.e., the front wheels 15, 18 and rear wheels 16, 17 independently from each other. The braking force for the whole vehicle is improved. When the obtained slip ratio λ is smaller, the select low control of the rear wheels 16, 17 is realized. The vehicle becomes stable thereby.

Method for controlling anti-lock brake of vehicle

The ABS system determines the braking effect and the slip characteristic for each wheel. The system compares the braking effect with a threshold value (RT) and reduces the braking effect when the threshold value is exceeded and reduces a predefined slip threshold value (ST) by a defined decrement value (b).If the braking effect is less than the braking effect threshold level the slip characteristic is compared with the slip threshold value. If the slip threshold is exceeded, the braking effect is reduced and the slip threshold value is increased by a defined increment value (a).

Nobuaki Okumoto

Papers

Anti-skid control method

Vehicle anti-lock braking control system (ABS)

Traction controlling method and controller thereof

Method for controlling anti-lock brake of vehicle

Anti-lock braking system for motor vehicles