Method and apparatus for monitoring a transport refrigeration system and its conditioned load

Claim 3

The method of claim 1 including the step of: providing a second diagnostic signal in response to the relating step which is indicative of a shutdown due to an extended cooling cycle, when the actual mode is a cooling mode, the system is not in defrost, and the actual and desired modes are inconsistent.

Claim 4

The method of claim 2 including the steps of: providing a logic signal I having a first logic level which indicates the differential temperature DI is significant enough under existing operating conditions to indicate adequate refrigeration capacity, and a second logic level which indicates inadequate refrigeration capacity, providing the shut down signal S a predetermined period of time after signal I indicates refrigeration capacity is inadequate, and providing a third diagnostic signal when the shut down signal S is provided while signal I is a at a logic level which indicates inadequate refrigeration capacity.

Claim 5

The method of claim 1 including the step of: providing a fourth diagnostic signal when the shut-down signal S is provided while the defrost signal D indicates a defrost cycle is desired.

Claim 6

Apparatus for monitoring, and protecting a transport refrigeration system and a load in a load space to be conditioned by the transport refrigeration system, with the transport refrigeration system having a selectable set point temperature for the load space which is maintained by heating and cooling modes, comprising: thermostat means providing a signal H having a logic level indicative of whether the desired mode of the refrigeration system is heating or cooling, defrost means providing a signal D having a logic level indicative of whether or not a defrost mode is desired, first temperature detector means detecting the temperature T1 of air discharged from the refrigeration system into the load space, second temperature detector means detecting the temperature T2 of air returning to the refrigeration system from the load space, difference means responsive to T1 and T2 for providing a difference signal DI having a sign and magnitude responsive to the difference between T1 and T2, means responsive to the difference signal DI for providing a logic signal A having first and second logic levels indicative of actual heating and actual cooling modes, respectively, means comparing the actual mode signal A with the desired mode signal H, and providing a logic signal N having a logic level indicative of whether or not the actual mode is consistent with the desired mode, timer means for providing a shut-down signal S when the actual mode signal A and the desired mode signal H are inconsistent for a predetermined period of time, logic means logically relating the actual mode signal A, the mode consistency signal N, and the defrost signal D, when the shut-down signal S is provided, said logic means providing a first diagnostic signal indicative of a shutdown due to an extended heating cycle, when the actual mode signal A indicates a heating mode, the defrost signal D indicates the system is not in defrost, and the mode consistency signal N indicates the actual and desired modes are not consistent.

Claim 7

Apparatus for monitoring, and protecting a transport refrigeration system and a load in a load space to be conditioned by the transport refrigeration system, with the transport refrigeration system having a selectable set point temperature for the load space which is maintained by heating and cooling modes, comprising: thermostat means providing a signal H having a logic level indicative of whether the desired mode of the refrigeration system is heating or cooling, defrost means providing a signal D having a logic level indicative of whether or not a defrost mode is desired, first temperature detector means detecting the temperature T1 of air discharged from the refrigeration system into the load space, second temperature detector means detecting the temperature T2 of air returning to the refrigeration system from the load space, difference means responsive to T1 and T2 for providing a difference signal DI having a sign and magnitude responsive to the difference between T1 and T2, means responsive to the difference signal DI for providing a logic signal A having first and second logic levels indicative of actual heating and actual cooling modes, respectively, means comparing the actual mode signal A with the desired mode signal H, and providing a logic signal N having a logic level indicative of whether or not the actual mode is consistent with the desired mode, timer means for providing a shut-down signal S when the actual mode signal A and the desired mode signal H are inconsistent for a predetermined period of time, logic means logically relating the actual mode signal A, the mode consistency signal N, and the defrost signal D, when the shut-down signal S is provided, said logic means providing a first diagnostic signal indicative of a shutdown due to an extended heating cycle, when the actual mode signal A indicates a heating mode, the defrost signal D indicates the system is not in defrost, and the mode consistency signal N indicates the actual and desired modes are not consistent.

Claim 8

The apparatus of claim 5 wherein the logic means provides a second diagnostic signal which is indicative of a shutdown due to an extended cooling cycle, when the actual mode signal A indicates a cooling mode, the defrost signal D indicates the system is not in defrost, and the mode consistency signal N indicates the actual and desired modes are not consistent.

Claim 9

The apparatus of claim 6 including: means providing a logic signal I having a first logic level which indicates the differential temperature DI is significant enough under existing operating conditions to indicate adequate refrigeration capacity, and a second logic level which indicates inadequate refrigeration capacity, and wherein the timer means provides the shut down signal S a predetermined period of time after signal I indicates inadequate refrigeration capacity, and the logic means provides a third diagnostic signal when the shut down signal S is provided while signal I is a at a logic level which indicates inadequate capacity.

Claim 10

The apparatus of claim 7 wherein the logic means provides a fourth diagnostic signal when the shut-down signal S is provided while the defrost signal D indicates a defrost cycle is desired.