Honda Giken Kogyo Kabushiki Kaisha

Norihisa Nihanda

Kenzo Nishida

There is disclosed a driving force control system for a four-wheel drive vehicle, which is capable of properly controlling the execution and cancellation of a lock mode in which the engagement forces of clutches for distributing a driving force to auxiliary drive wheels are made maximum, thereby reducing frequency and duration of the lock mode. Further, there is disclosed a driving force control system for a four-wheel drive vehicle, which is capable of properly controlling the engagement forces of clutches for distributing a driving force of the main drive wheels to auxiliary drive wheels, thereby causing the clutches to efficiently operate without waste of power.

Driving force control system for four-wheel drive vehicles

An apparatus for determining a failure of an electromagnetic clutch, which is capable of properly determining whether or not a failure, a typically a layer short-circuit, has occurred due to a change in a resistance value of a solenoid coil of the electromagnetic clutch. The electromagnetic clutch is configured such that the engagement force thereof is varied according to an amount of current flowing through the coil. An output control value for control of the amount of current is calculated by feedback control such that an actual amount of current actually flowing through the coil becomes equal to a desired amount of current. A predetermined reference control value is stored which defines a standard for the output control value and has a standard relationship with respect to the amount of current. The actual amount of current is detected. The calculated output control value is compared with the predetermined reference control value corresponding to the detected actual amount of current. It is determined based on a result of the comparison by the comparison means whether or not the electromagnetic clutch has failed due to a change in a resistance value of the coil of the solenoid thereof.

Apparatus for determining failure of electromagnetic clutch

A driving force control system for a four-wheel drive vehicle, which is capable of preventing occurrence of a tight-turn braking phenomenon by relatively simple construction to thereby reduce the manufacturing cost thereof, and at the same time, enhancing the response of slippage-eliminating control on main drive wheels, and stability of the vehicle. The 2/WD&middot;ECU of the driving force control system controls electromagnetic clutches of a four-wheel drive vehicle having front wheels as main drive wheels and rear wheels as auxiliary drive wheels, whereby the LSD torque to be distributed to the rear wheels is controlled. More specifically, the front-wheel/rear-wheel slip ratio is determined from the average front wheel speed and the average rear wheel speed, and the left/right rear-wheel speed ratio and the front-wheel/rear-wheel slip ratio threshold are determined according to the rear wheel speeds, and a first LSD torque for use in calculation of the LSD torque is determined based on the difference between the front-wheel/rear-wheel slip ratio and the front-wheel/rear-wheel slip ratio threshold.

A driving force control system for a four-wheel drive vehicle for controlling the execution and cancellation of a lock mode in which the engagement forces of clutches for distributing a driving force to auxiliary drive wheels are made maximum. The driving force control system properly controls the engagement forces of clutches for distributing a driving force of the main drive wheels to auxiliary drive wheels. When the vehicle is determined to be in a predetermined low vehicle speed condition and the transmission is in any of predetermined low-speed shift positions, execution of a lock mode is permitted in which the clutch engagement forces are controlled to lock the main and auxiliary drive wheels to each other. When the driving force of the main drive wheels is lower than a predetermined value, the clutch engagement forces for the lock mode are limited to smaller ones than the lockable ones.

A driving force control system for a four-wheel drive vehicle&lsqb;is disclosed&rsqb; which enables the vehicle to smoothly start on a low-&mgr; road surface, and is capable to distributing just required amounts or driving forces to auxiliary drive wheels depending on an actual accelerating condition of the vehicle, thereby improving the response and fuel economy of the vehicle. The four-wheel drive vehicle includes front wheels as main drive wheels, and rear wheels as auxiliary drive wheels. The driving force control system controls engagement forces of electromagnetic clutches to thereby control the driving forces (torques) distributed to the rear wheels. The 2/4WD&middot;ECU of the driving force control system calculates a filtered vehicle acceleration XGF1F of the vehicle based on a drive torque TD, and then calculates a basic VATC torque value VATC based on the calculated filtered vehicle acceleration XGF F, for use in calculation of the final desired VATC torque value TOBJM of torque to be distributed to the rear wheels.

A driving force control system for a four-wheel drive vehicle. An automatic-mode transmitted torque is calculated based on operating conditions of the vehicle. When lock mode-executing conditions including operation of a lock switch by the driver are satisfied, a lock mode in which the engagement forces of the clutches are set to a lock-mode transmitted torque, including a lockable transmitted torque which can lock the front wheels and the rear wheels to each other. Further, the lock mode transmitted torque is limited depending on a traveling condition of the vehicle such that the lock-mode transmitted torque is held below the lockable transmitted torque. When the automatic-mode transmitted torque is larger than the limited lock-mode transmitted torque during the lock-mode, the engagement forces of the clutches are set to the automatic-mode transmitted torques.

An apparatus for determining a failure of wheel speed sensors, which is capable of properly determining whether or not a wheel speed detection system including the wheel speed sensors has failed, if at least a wheel speed detected by the wheel speed sensors indicates a stopped state of a corresponding wheel. An engine rotational speed is detected, and an input-output rotational speed ratio of a torque converter of an automatic transmission mounted in the vehicle is calculated. A shift range of the automatic transmission is detected. Whether or not the vehicle is traveling is determined based on the engine rotational speed and the input-output rotational speed ratio when the automatic transmission is in a traveling range. It is determined that the wheel speed detection system including the wheel speed sensors has failed, if it is determined that the vehicle is traveling, and at the same time, at least one of wheel speed sensors indicates a stopped state of a corresponding one of the wheels.

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Saitama-ken, Japan

Norihisa Nihanda