Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
1999-10-15
2001-04-24
Solis, Erick (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C123S493000
Reexamination Certificate
active
06220226
ABSTRACT:
The present invention relates to a method of controlling changes in torque in an internal combustion engine having a control unit, which controls the amount of fuel to the engine combustion chambers dependent on signals fed into the control unit which represent at least the accelerator pedal position and engine speed.
The invention also relates to an internal combustion engine for motor vehicles with an injector for each cylinder and an electronic control unit, controlling the amount of fuel which is injected into the combustion chamber of the respective cylinder, dependent on signals, fed into the control unit, representing at least accelerator position and engine speed.
The fuel injection in vehicle engines with unit injectors can be controlled very carefully and rapidly, which means that the torque from the engine can change quite rapidly. At times this can result in problems for certain parts of the vehicle drive train, i.e. the gearbox, the rear axle and the wheel suspension, which do not handle satisfactorily torque transmission during the rapid torque transients which can occur. The problems manifest themselves in the form of banging and knocking in the gearbox, rear axle and/or the wheel suspension. The rapid torque increases and decreases, which can occur in engines with unit injectors, can also cause such heavy impacts in the drive train that certain types of rear axles and wheel suspensions cannot, in practice, be used unless the changes in torque can be effected in a controlled manner so that the torque transients are dampened.
One purpose of the present invention is to achieve a method of controlling, in an internal combustion engine, torque changes initiated by changes in the accelerator position so that the torque change is effected smoothly and passes the zero torque level in a controlled manner, i.e. the transition from braking to pulling torque or vice versa, to give the rest of the drive train time to take up the gap and eliminate or reduce the twisting up of various chassis components.
This is achieved according to the invention by virtue of the fact that the amount of fuel is controlled in such a manner by the control unit, that a change in the accelerator pedal position from a position representing a current engine torque to a new position representing a requested engine torque and which involves a shift from braking to driving torque or conversely from driving to braking torque, results in signals from the control unit to control the amount of fuel so that an engine torque different from the requested torque is first achieved and that, during a predetermined time interval, the amount of fuel is thereafter gradually controlled towards a level corresponding to the requested or a maximum permitted torque.
An internal combustion engine of the type described by way of introduction is characterized according to the invention in that in the control unit there are stored values of the frictional torque of the engine as a function of engine speed, and values of first and second upper and lower torque limits related to the frictional torque, and that the control unit is arranged, when the accelerator pedal position is changed from a position representing a current engine torque to a new position representing a requested engine torque lying, for opening throttle, above said first upper torque limit or, for closing throttle, below said second lower torque limit, to control the amount of fuel so that an engine torque different from the requested torque is first achieved and that, during a predetermined time interval, the amount of fuel is thereafter controlled towards a level corresponding to the requested or to the maximum permissible torque.
REFERENCES:
patent: 5163530 (1992-11-01), Nakamura et al.
patent: 5213178 (1993-05-01), Polidan et al.
patent: 5225892 (1993-07-01), Ito et al.
patent: 5625558 (1997-04-01), Togai et al.
patent: 5899830 (1999-05-01), Tabata
Alm Christer
Hansson Gote
Solis Erick
Volvo Lastvagnar AB
Young & Thompson
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