Hybrid vehicle powertrain with a multiple-ratio power transmission mechanism
First Claim
1. A method for controlling engagement and release of pressure-actuated torque establishing friction elements during a power-on upshift of a multiple-ratio transmission in a hybrid electric vehicle powertrain having an engine, an electric motor and a battery, the motor being disposed in a power flow path between the engine and a power input element of the transmission as driving power is delivered to a transmission power output member, and an electronic controller responsive to powertrain operating variables for controlling actuating pressure for the friction elements by releasing actuating pressure for an off-going friction element in synchronism with increasing actuating pressure for an oncoming friction element during a power-on upshift event, the method comprising the steps of:
- increasing oncoming friction element actuating pressure at the beginning of the power-on upshift event;
reducing actuating pressure for the off-going friction element during a torque phase of the power-on upshift;
increasing electric motor torque during the torque phase; and
reducing electric motor torque during an inertia phase of a power-on upshift whereby torque variations in the transmission power output member are modulated.
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Accused Products
Abstract
A control method and system for a hybrid vehicle powertrain with an electric motor in a power flow path between an internal combustion engine and a multiple-ratio geared transmission. Motor torque, which is added to engine torque to obtain an effective transmission input torque, is modulated to achieve smooth power-on upshifts and coasting downshifts.
33 Citations
10 Claims
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1. A method for controlling engagement and release of pressure-actuated torque establishing friction elements during a power-on upshift of a multiple-ratio transmission in a hybrid electric vehicle powertrain having an engine, an electric motor and a battery, the motor being disposed in a power flow path between the engine and a power input element of the transmission as driving power is delivered to a transmission power output member, and an electronic controller responsive to powertrain operating variables for controlling actuating pressure for the friction elements by releasing actuating pressure for an off-going friction element in synchronism with increasing actuating pressure for an oncoming friction element during a power-on upshift event, the method comprising the steps of:
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increasing oncoming friction element actuating pressure at the beginning of the power-on upshift event; reducing actuating pressure for the off-going friction element during a torque phase of the power-on upshift; increasing electric motor torque during the torque phase; and reducing electric motor torque during an inertia phase of a power-on upshift whereby torque variations in the transmission power output member are modulated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A control system for controlling ratio changes in a multiple-ratio transmission in a hybrid electric vehicle powertrain, the transmission having selectively-engageable, pressure-actuated torque establishing friction elements for effecting powertrain upshifts;
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the powertrain having an engine, an electric motor and a battery, the motor being disposed in a power flow path between the engine and a power input member of the transmission as driving power is delivered to a power output member; the control system comprising an electronic controller responsive to powertrain operating variables for controlling actuating pressure for the friction elements; the control system controller being configured to control actuating pressure for the friction elements by releasing actuating pressure for an off-going friction element in synchronism with increasing actuating pressure for an oncoming friction element during a power-on upshift; the motor being disposed in series relationship with respect to the engine and the transmission; and the control system including means for increasing motor torque during a torque phase and reducing motor torque during an inertia phase of a power-on upshift of the transmission.
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Specification