DYNAMIC SHIFT SCHEDULING IN A HYBRID VEHICLE HAVING A STEP RATIO AUTOMATIC TRANSMISSION
First Claim
1. A method for controlling a target gear selection in a hybrid vehicle with an internal combustion engine, a motor, and a step ratio automatic transmission, and a powertrain controller having a first shift schedule for selecting a first target gear ratio based on drive demand and output speed, the method comprising:
- establishing a second shift schedule having second target gear ratios based on efficient operating speeds of the engine and the motor for current output speed and the drive demand;
weighting the first target gear ratio and the second target gear ratios;
arbitrating the weighted first gear ratio and each of the weighted second gear ratios to select a desired target gear ratio; and
shifting the transmission for engagement of the desired target gear ratio.
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Accused Products
Abstract
A hybrid vehicle having an engine and motor in series with a step ratio automatic transmission shifts the transmission according to a first shift schedule based on driver demand and output speed or a second shift schedule based on efficient operating speeds of the engine and motor associated with the target gear ratio. A powertrain controller continually calculates engine and motor speeds and torques associated with target gear ratios for the second shift schedule to select a gear ratio based on operating efficiency. An arbitration strategy may compare a weighted target gear ratio from the first schedule shift schedule to a weighted target gear ratio from the second shift schedule to dynamically select a desired target gear for powertrain control management.
48 Citations
20 Claims
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1. A method for controlling a target gear selection in a hybrid vehicle with an internal combustion engine, a motor, and a step ratio automatic transmission, and a powertrain controller having a first shift schedule for selecting a first target gear ratio based on drive demand and output speed, the method comprising:
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establishing a second shift schedule having second target gear ratios based on efficient operating speeds of the engine and the motor for current output speed and the drive demand; weighting the first target gear ratio and the second target gear ratios; arbitrating the weighted first gear ratio and each of the weighted second gear ratios to select a desired target gear ratio; and shifting the transmission for engagement of the desired target gear ratio. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A hybrid vehicle comprising:
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an engine; an automatic transmission having a torque converter with an impeller and a turbine and selectable step gear ratios; a traction motor coupled to the impeller and selectively coupled to the engine by a disconnect clutch; and a powertrain controller configured to control gear selection with respect to a first shift schedule for each of the selectable step gear ratios as a function of drive demand and vehicle output speed, and a second shift schedule for each of the selectable step gear ratios as a function of engine operating speed and torque and motor operating speed and torque. - View Dependent Claims (12, 13, 14, 15)
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16. A hybrid vehicle, comprising:
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an engine; an electric machine coupled by a disconnect clutch to the engine; a traction battery coupled to the electric machine; an automatic transmission coupled to the electric machine by a torque converter; and a controller configured to shift the automatic transmission according to a first shift schedule based on drivability and a second shift schedule based on efficient operating speeds of the engine and electric machine. - View Dependent Claims (17, 18, 19, 20)
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Specification