Method of operating a transport refrigeration unit
First Claim
1. A method of modifying the operation of a refrigeration unit when a condition is detected which may result in shutdown of the unit, with the refrigeration unit having a refrigerant compressor driven at low and high speeds by an internal combustion engine, with the engine including a temperature sensor, comprising the steps of:
- monitoring the temperature of the engine,detecting a predetermined over-temperature condition,initiating a first modification of the refrigeration unit, including the step of switching the engine to low speed when it is in high speed at the time the detecting step detects the predetermined over-temperature condition,determining if the engine temperature has dropped below a predetermined value after the step of switching to low speed,initiating a second modification of the refrigeration unit when the engine temperature does not drop below the predetermined value,maintaining the engine at low speed when it is in low speed when the detecting step detects the predetermined over-temperature condition, andinitiating the second modification of the refrigeration unit immediately when the engine is in low speed at the time the detecting step detects the predetermined over-temperature condition.
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Accused Products
Abstract
A method of detecting conditions during the operation of a transport refrigeration unit which may cause shutdown, and then modifying the operation of the unit in an attempt to find an operating condition that will keep the unit operating safely. The unit includes a compressor driven by an engine operable at low and high speeds. Upon detecting an over-temperature condition of the engine a first modification is initiated, including switching the engine to low speed. If the engine temperature does not drop to a safe value, a second modification is initiated. If the engine was in low speed when the over-temperature condition was detected, the second modification is initiated immediately. Upon detecting a low oil pressure condition, the engine is switched to high speed. If the oil pressure rises to a safe level, engine operation is continued at high speed. Appropriate alarms accompany the modified operating conditions.
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Citations
12 Claims
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1. A method of modifying the operation of a refrigeration unit when a condition is detected which may result in shutdown of the unit, with the refrigeration unit having a refrigerant compressor driven at low and high speeds by an internal combustion engine, with the engine including a temperature sensor, comprising the steps of:
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monitoring the temperature of the engine, detecting a predetermined over-temperature condition, initiating a first modification of the refrigeration unit, including the step of switching the engine to low speed when it is in high speed at the time the detecting step detects the predetermined over-temperature condition, determining if the engine temperature has dropped below a predetermined value after the step of switching to low speed, initiating a second modification of the refrigeration unit when the engine temperature does not drop below the predetermined value, maintaining the engine at low speed when it is in low speed when the detecting step detects the predetermined over-temperature condition, and initiating the second modification of the refrigeration unit immediately when the engine is in low speed at the time the detecting step detects the predetermined over-temperature condition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification