Fail-safe engine cooling control algorithm for hybrid electric vehicle
First Claim
1. A fail-safe engine cooling control system for a hybrid electric vehicle (HEV) when the engine temperature exceeds a predetermined calibratable level comprising:
- An electric traction motor;
An engine;
An Engine temperature sensor;
A system to cool the engine, whereby safe and efficient engine operating temperatures are maintained;
A Vehicle System Controller;
A fail-safe system to assure that in the event the system to cool the engine fails, acceptable engine temperatures are maintained while vehicle operating range is extended, adequate power is provided to the vehicle, and noise, vibration and harshness (NVH) is kept to a minimum.
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Abstract
This invention is a fail-safe algorithm for a hybrid electric vehicle (HEV). The method and system allow an HEV to continue to operate without damage after the engine cooling system is compromised, such as when there has been a total loss of engine coolant. Goals include a fail-safe vehicle strategy to maintain acceptable engine temperatures and minimal noise, vibration and harshness (NVH), while greatly extending the vehicle'"'"'s operating range. First is a determination if the vehicle can rely on an electric traction motor'"'"'s torque output to operate the vehicle. If engine operation is needed, engine fueling and firing of the cylinders is alternated to allow those cylinders to cool when no combustion is occurring. Engine speed is also optimized. NVH must remain within acceptable levels under most operating conditions. Further, the HEV parallel mode of operation (i.e., with a generator motor brake applied) is prohibited. And finally, the speed of at least one engine compartment cooling fan is optimized to minimize electrical load while maximizing airflow.
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Citations
14 Claims
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1. A fail-safe engine cooling control system for a hybrid electric vehicle (HEV) when the engine temperature exceeds a predetermined calibratable level comprising:
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An electric traction motor;
An engine;
An Engine temperature sensor;
A system to cool the engine, whereby safe and efficient engine operating temperatures are maintained;
A Vehicle System Controller;
A fail-safe system to assure that in the event the system to cool the engine fails, acceptable engine temperatures are maintained while vehicle operating range is extended, adequate power is provided to the vehicle, and noise, vibration and harshness (NVH) is kept to a minimum. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A fail-safe engine cooling control method for a hybrid electric vehicle (HEV) when engine temperature exceeds a predetermined calibratable level comprising the steps of:
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Sensing Engine temperature;
Cooling the engine, whereby safe and efficient engine operating temperatures are maintained;
Controlling Vehicle systems; and
Assuring through a fail-safe system that in the event the system to cool the engine fails, comprising the steps of maintaining acceptable engine temperatures, extending vehicle operating range, powering the vehicle adequately, and minimizing noise, vibration and harshness (NVH). - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification