Method of operating a transport refrigeration unit
First Claim
1. A method of checking electrical components and associated wiring of electrical control associated with a microprocessor controlled transport refrigeration system having a prime mover which includes an internal combustion engine, with the prime mover driving a refrigerant compressor and an alternator, and with the electrical control including a battery, comprising the steps of:
- turning the prime mover off so the alternator output is zero,providing a DC current shunt to directly measure battery current,providing upper and lower battery current draw limits for each of a predetermined plurality of electrical components of the electrical control,energizing and de-energizing each of said plurality of electrical components, by individually, successively, and automatically connecting, without human intervention, each component to, and disconnecting it from, the battery,comparing the directly measured battery current draw of each of said plurality of electrical components, when energized, with the associated battery current draw limits,providing an alarm when a directly measured battery current draw is outside the associated draw limits, andidentifying the electrical component whose directly measured battery current draw is outside the associated draw limits.
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Accused Products
Abstract
A method of automatically checking components and associated wiring of electrical control associated with a microprocessor controlled transport refrigeration system. The transport refrigeration system has a prime mover which drives a refrigerant compressor and an alternator. The control includes a battery and a current shunt which measures battery current. During the automatic checking procedure, the prime mover is off, to provide a zero alternator output. Upper and lower battery current draw limits are provided for each component to be checked. Each of the components to be checked is energized and de-energized, with the microprocessor individually and successively connecting each component to, and disconnecting it from, the battery. The microprocessor compares the battery current draw of each component, when energized, with the associated battery current draw limits. An alarm is provided when a battery current draw is outside the associated draw limits, with the alarm identifying the associated component.
36 Citations
9 Claims
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1. A method of checking electrical components and associated wiring of electrical control associated with a microprocessor controlled transport refrigeration system having a prime mover which includes an internal combustion engine, with the prime mover driving a refrigerant compressor and an alternator, and with the electrical control including a battery, comprising the steps of:
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turning the prime mover off so the alternator output is zero, providing a DC current shunt to directly measure battery current, providing upper and lower battery current draw limits for each of a predetermined plurality of electrical components of the electrical control, energizing and de-energizing each of said plurality of electrical components, by individually, successively, and automatically connecting, without human intervention, each component to, and disconnecting it from, the battery, comparing the directly measured battery current draw of each of said plurality of electrical components, when energized, with the associated battery current draw limits, providing an alarm when a directly measured battery current draw is outside the associated draw limits, and identifying the electrical component whose directly measured battery current draw is outside the associated draw limits. - View Dependent Claims (2)
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3. A method of checking electrical components and associated wiring of electrical control associated with a microprocessor controlled transport refrigeration system having a prime mover which includes an internal combustion engine having glow plug resistors for pre-heating the engine, with the prime mover driving a refrigerant compressor and an alternator, and with the electrical control including a battery and a pre-heat relay which, when energized, energizes the glow plug resistors, comprising the steps of:
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turning the prime mover off so the alternator output is zero, providing predetermined upper and lower voltage limits for the battery, measuring the battery voltage, comparing the battery voltage with said voltage limits, providing an alarm which indicates the battery voltage is outside the predetermined upper and lower limits in response to the comparison step finding that the battery voltage is not within the upper and lower voltage limits, providing a current shunt to measure battery current, providing upper and lower battery current draw limits for each of a predetermined plurality of electrical components of the electrical control, energizing and de-energizing each of said plurality of electrical components, by individually and successively connecting each component to, and disconnecting it from, the battery, comparing the battery current draw of each of said plurality of electrical components, when energized, with the associated battery current draw limits, providing an alarm when a battery current draw is outside the associated draw limits, identifying the electrical component whose battery current draw is outside the associated draw limits, said step of providing battery current draw limits providing predetermined upper and lower battery current limits for current collectively drawn by the pre-heat relay and glow plug resistors, energizing the pre-heat relay and glow plug resistors, measuring the battery current drawn by the energized pre-heat relay and glow plug resistors, comparing the measured battery current with the predetermined upper limit, providing an alarm which indicates the glow plug current is out of limits when the comparison step finds the measured battery current exceeds the predetermined upper current limit, comparing the measured battery current with the predetermined lower current limit, providing an additional lower limit for the battery voltage which is lower than the predetermined lower limit previously sued to check the battery voltage, comparing the battery voltage with the additional lower limit when the comparison step finds the measured battery current is less than the predetermined lower current limit, providing an alarm which identifies the glow plugs when the measured current is below the predetermined lower limit and the battery voltage is above the additional lower voltage limit, and providing an alarm which identifies the battery when the measured current is below the predetermined lower limit and the battery voltage is below the additional lower voltage limit.
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4. A method of checking electrical components and associated wiring of electrical control associated with a microprocessor controlled transport refrigeration system having a prime mover which includes an internal combustion engine, with the prime mover driving a refrigerant compressor and an alternator, and with the electrical control including a battery, and a run relay which is energized when the engine is the prim mover, comprising the steps of:
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turning the prime mover off so the alternator output is zero, providing a current shunt to measure battery current, providing upper and lower battery current draw limits for each of a predetermined plurality of electrical components of the electrical control, including the run relay, energizing and de-energizing each of said plurality of electrical components, by individually and successively connecting each component to, and disconnecting it from, the battery, comparing the battery current draw of each of said plurality of electrical components, when energized, with the associated battery current draw limits, providing an alarm when a battery current draw is outside the associated draw limits, identifying the electrical component whose battery current draw is outside the associated draw limits, said step of energizing electrical components including the step of energizing the run relay, de-energizing the run relay only if the battery current drawn by the run relay is outside the predetermined upper and lower battery current limits for the run relay, and storing the battery current drawn by the energized run relay as value Z when the battery current drawn by the run relay is within the predetermined upper and lower limits. - View Dependent Claims (5, 6, 7)
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8. A method of checking electrical components and associated wiring of electrical control associated with a microprocessor controlled transport refrigeration system having a prime mover which includes an internal combustion engine, with the prime mover driving a refrigerant compressor and an alternator, and with the electrical control including a battery, comprising the steps of:
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turning the prime mover off so the alternator output is zero, providing a current shunt to measure battery current, providing upper and lower battery current draw limits for each of a predetermined plurality of electrical components of the electrical control, energizing and de-energizing each of said plurality of electrical components, by individually and successively connecting each component to, and disconnecting it from, the battery, comparing the battery current draw of each of said plurality of electrical components, when energized, with the associated battery current draw limits, providing an alarm when a battery current draw is outside the associated draw limits, identifying the electrical component whose battery current draw is outside the associated draw limits, storing the measured battery current as value A when at least one of the electrical components is energized, measuring the battery current (value B) after the at least one electrical component is de-energized, comparing value B with value A, and providing an alarm which identifies the at least one electrical component when value B exceeds value A.
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9. A method of checking electrical components and associated wiring of electrical control associated with a microprocessor controlled transport refrigeration system having a controllable suction line modulation valve which closes in response to a predetermined current flow therethrough, and which opens with zero current, a prime mover which includes an internal combustion engine, with the prime mover driving a refrigerant compressor and an alternator, and with the electrical control including a battery, comprising the steps of:
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turning the prime mover off so the alternator output is zero, providing a current shunt to measure battery current, providing upper and lower battery current draw limits for each of a predetermined plurality of electrical components of the electrical control, energizing and de-energizing each of said plurality of electrical components, by individually and successively connecting each component to, and disconnecting it from, the battery, comparing the battery current draw of each of said plurality of electrical components, when energized, with the associated battery current draw limits, providing an alarm when a battery current draw is outside the associated draw limits, identifying the electrical component whose battery current draw is outside the associated draw limits, providing on output to the modulation valve which would normally provide the predetermined valve closing current, measuring the battery current (value A) after a time sufficient for the modulation valve to close, providing predetermined upper and lower current limits for the modulation valve when closed, comparing value A with the upper and lower current limits, providing an alarm which identifies the modulation valve when value A is outside the upper and lower current limits, providing on output to the modulation valve which would normally provide the zero valve opening current, measuring the battery current (value B) after a time sufficient for the modulation valve to open, comparing value B with value A, and providing an alarm which identifies the modulation valve when value B exceeds value A.
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Specification