Honda Giken Kogyo Kabushiki Kaisha

Ryuji Asada

Masakatsu Hori

Akihiro Iwazaki

Tatsuhiro Tomari

Kiyoshi Wakamatsu

Shinji Okuma

Takashi Kuribayashi

Shinji Ohkuma

Kazuhiro Wada

In a vehicle in which a torque generated in an engine is transmitted to driven wheels through a torque converter and an automatic transmission, when a speed ratio e in the torque converter is equal to or larger than a predetermined value (e.g., 0.85), and the accuracy of estimating a capacity &tgr; of the torque converter is low, an estimated engine torque Ti is multiplied by a torque ratio k of the torque converter to estimate a drive torque Td. When the speed ratio e in the torque converter is smaller than the predetermined value, and a response lag is produced in the transmission of the engine torque, a drive torque Td is estimated from an engine rotational sped Ne and the speed ratio e in the torque converter. During shifting of the automatic transmission, a drive torque Td is estimated from a wheel speed V. Thus, a correct drive torque can be estimated.

Process for estimating drive torque in vehicle

The engagement force of an electromagnetic clutch can be precisely controlled at a target engagement force by a simple structure even when an air gap of the electromagnetic clutch varies. An electromagnetic clutch control system includes magnetic flux density sensors, a target engagement force calculating device, a target magnetic flux density calculating device, and a feedback control device. The target magnetic flux density calculating device calculates a target magnetic flux density &phgr;t based on a target engagement force Tt of electromagnetic clutches calculated by the target engagement force calculating device. The current supplied to the electromagnetic clutches is feedback controlled by the feedback control device so that an actual magnetic flux density &phgr; detected by the magnetic flux density sensors agrees with the target magnetic flux density &phgr;t. This allows a target engagement force to be generated in the electromagnetic clutches by making the actual magnetic flux density agree precisely with the target magnetic flux density, even when the air gap varies due to wear of a frictional engagement member, etc. and the relationship between the actual magnetic flux density and the current supplied to the electromagnetic clutches changes.

Electromagnetic clutch control system

A driving force distribution device which controls the engagement forces of electromagnetic clutches and which govern the torque distribution between the driving wheels of a vehicle by calculating a target magnetic flux density and converting the same into a target excitation current. Since the relationship between the target magnetic flux density and the target excitation current changes according to a decrease in the air gaps accompanying wear of the frictional engagement members of the electromagnetic clutches, a relationship between the magnetic flux density and the excitation current is determined by applying current to the electromagnetic clutches when torque distribution control is not being carried out such as when the system is started, and the target excitation current is calculated from the target magnetic flux density based on the determined relationship. Since there is no need to detect dynamic changes in the magnetic flux density, inexpensive devices can be used as magnetic flux density detecting means so contributing to a reduction in the cost.

Driving force distribution device for vehicle

Growing community of inventors

Wako, Japan

Ryuji Asada