Crankshaft rotation control in a hybrid electric vehicle
First Claim
1. A method of controlling engine crankshaft motion in a hybrid electric drive system having an internal combustion engine and a motor-generator operatively connected to a crankshaft of the engine, comprising the steps of:
- monitoring the crankshaft position;
forecasting a crankshaft stall position;
comparing the forecast stall position with a target range; and
if the forecast crankshaft stall position is outside the target range, operating the motor-generator to modify the forecast stall position to be within the target range.
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Abstract
A method of controlling engine crankshaft motion in a hybrid electric drive system having an internal combustion engine and a motor-generator operatively connected to a crankshaft of the engine is disclosed. The steps include monitoring the crankshaft position, forecasting a crankshaft stall position; comparing the forecast stall position with a target range; and if the forecast crankshaft stall position is outside the target range, operating the motor-generator to modify the forecast stall position to be within the target range. These steps properly position the crankshaft for re-initiating engine start-up. The method further includes the steps of calculating an effective lube interval time once the crankshaft speed is zero; comparing the effective lube interval time to a critical time; and if the effective lube interval time is greater than the critical time, pulsing the motor-generator to rock the crankshaft for a pulse time to redistribute a lubricant film.
83 Citations
11 Claims
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1. A method of controlling engine crankshaft motion in a hybrid electric drive system having an internal combustion engine and a motor-generator operatively connected to a crankshaft of the engine, comprising the steps of:
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monitoring the crankshaft position;
forecasting a crankshaft stall position;
comparing the forecast stall position with a target range; and
if the forecast crankshaft stall position is outside the target range, operating the motor-generator to modify the forecast stall position to be within the target range. - View Dependent Claims (2, 3, 4, 5, 6, 7)
applying a preloading torque to the crankshaft in the direction of crankshaft rotation; and
applying regenerative braking to slow the crankshaft to stall within the target range.
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3. The method of claim 2, further comprising the steps of:
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after operating the motor-generator, monitoring the crankshaft speed;
if the crankshaft speed is zero, comparing the crankshaft stall position to the target range; and
if the crankshaft stall position is outside the target range, operating the motor-generator to modify the crankshaft stall position to be within the target range.
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4. The method of claim 3, further comprising the step of:
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after the crankshaft speed is zero, calculating an effective lube interval time;
comparing the effective lube interval time to a critical time; and
if the effective lube interval time is greater than the critical time, pulsing the motor-generator to rock the crankshaft for a pulse time to redistribute a lubricant film.
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5. The method of claim 4, wherein the step of calculating the effective lube interval time further comprising the steps of:
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monitoring engine coolant temperature;
monitoring engine oil pressure; and
monitoring how long the crankshaft speed is zero without motor-generator pulsations.
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6. The method of claim 5, further comprising the step of:
summing the pulse times.
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7. The method of claim 6, further comprising the step of:
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comparing the summed pulse time to a maximum time; and
if the summed pulse time is greater than the maximum time, discontinuing further pulsing of the motor-generator.
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8. A method of controlling engine crankshaft motion for lubrication redistribution in a hybrid electric drive system having an internal combustion engine and a motor-generator operatively connected to a crankshaft of the engine, comprising the steps of:
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monitoring crankshaft speed;
if crankshaft speed is zero, calculating an effective lube interval time;
comparing the effective lube interval time to a critical time;
if the effective lube interval time is greater than the critical time, pulsing the motor-generator to rock the crankshaft for a pulse time to redistribute a lubricant film. - View Dependent Claims (9, 10, 11)
monitoring engine coolant temperature;
monitoring engine oil pressure; and
monitoring how long the crankshaft speed is zero without motor-generator pulsations.
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10. The method of claim 9, further comprising the step of:
summing the pulse times.
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11. The method of claim 10, further comprising the steps of:
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comparing the summed pulse time to a maximum time; and
if the summed pulse time is greater than the maximum time, discontinuing further pulsing of the motor-generator.
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Specification