Abstract: A transport temperature control unit and methods of defrosting an evaporator coil of a transport temperature control unit. The transport temperature control unit includes an evaporator coil, an ambient air temperature sensor for sensing an ambient air temperature, a return air temperature sensor for sensing a return air temperature, a discharge air temperature sensor for sensing a discharge air temperature, an evaporator coil temperature sensor for sensing an evaporator coil temperature, and a controller. The controller initiates a defrost cycle when a large temperature differential occurs over the evaporator coil.

Abstract: Methods of diagnosing a temperature control unit and methods of performing a diagnostic check on a temperature control unit. The methods generally include monitoring at least one function of the temperature control unit, storing information relating to the at least one monitored function, determining from the information relating to the at least one monitored function whether the unit has a malfunction. Some methods generally include setting a flag to one of a first setting and a second setting, the flag being set to the first setting if the unit has no malfunction and the flag being set to the second setting if the unit has at least one malfunction, and enabling the diagnostic check when the flag is set to the first setting.

Abstract: A method of controlling a transport temperature control unit having cooling and heating cycles for cooling and heating a conditioned space within a transport. The method includes programming a first pre-programmed control mode into the unit, configuring the unit such that a second control mode is programmable into the unit by an end user, querying the end user to select the first pre-programmed control mode or to program the second control mode into the unit, and programming the second control mode into the unit by the end user when the second control mode is desired by the end user. A transport temperature control unit for performing the same and including a first pre-programmed control mode being programmable into the unit and a second control mode being programmable into the unit by an end user.

Abstract: Methods of diagnosing a temperature control unit and methods of performing a diagnostic check on a temperature control unit. The methods generally include monitoring at least one function of the temperature control unit, storing information relating to the at least one monitored function, determining from the information relating to the at least one monitored function whether the unit has a malfunction. Some methods generally include setting a flag to one of a first setting and a second setting, the flag being set to the first setting if the unit has no malfunction and the flag being set to the second setting if the unit has at least one malfunction, and enabling the diagnostic check when the flag is set to the first setting.

Abstract: A transport temperature control unit and methods of defrosting an evaporator coil of a transport temperature control unit. The transport temperature control unit includes an evaporator coil, an ambient air temperature sensor for sensing an ambient air temperature, a return air temperature sensor for sensing a return air temperature, a discharge air temperature sensor for sensing a discharge air temperature, an evaporator coil temperature sensor for sensing an evaporator coil temperature, and a controller. The controller initiates a defrost cycle when a large temperature differential occurs over the evaporator coil.

Abstract: A method of controlling a transport temperature control unit having cooling and heating cycles for cooling and heating a conditioned space within a transport. The method includes programming a first pre-programmed control mode into the unit, configuring the unit such that a second control mode is programmable into the unit by an end user, querying the end user to select the first pre-programmed control mode or to program the second control mode into the unit, and programming the second control mode into the unit by the end user when the second control mode is desired by the end user. A transport temperature control unit for performing the same and including a first pre-programmed control mode being programmable into the unit and a second control mode being programmable into the unit by an end user.

Abstract: The invention provides a method of defrosting an evaporator coil of a transport temperature control unit. The transport temperature control unit may be operable to circulate refrigerant through the evaporator coil for cooling a conditioned space within a transportable vehicle and may be operable to maintain an air temperature of the conditioned space within a range of a desired temperature. The method may include sensing the air temperature of the conditioned space, enabling a warm load defrost when the air temperature of the conditioned space is greater than the desired temperature, initiating a first defrost cycle for removing condensate from the evaporator coil and terminating the first defrost cycle. The first defrost cycle has a defrost duration time. The method may also include establishing a defrost interval time dependent on the defrost duration time and initiating a second defrost cycle after the defrost interval time expires.

Abstract: A method and apparatus for making a pretrip diagnosis and identification of generator set problems which could cause shutdown or undesired operation of the generator set.

Abstract: A method for controlling a transport refrigeration system is provided that advantageously avoids the top-freezing of items stored in a conditioned space without the need for modulating the flow of refrigerant through the heater-evaporator coil that heats and cools the space. The method includes the steps of operating the refrigeration system in a cooling mode at high speed for no more than 300.degree. minutes below the temperature set point of the conditioned space to rapidly cool the space. Next, the system is operated in a low speed heating mode in order to raise the temperature of the conditioned space to no more than about 5.degree. F. above set point in order to avoid top-freezing items in the conditioned space. Thirdly, the refrigeration system is operated in a low speed cooling mode to reattain a temperature set point assigned to the conditioned space. If necessary, these three basic steps of the method may be reiterated in order to stabilize the temperature of the space at set point.

Abstract: A refrigeration unit of the type having an economizer cycle driven by a prime mover cooled by a liquid coolant. Electrical control configures refrigerant flow paths of the unit to provide heating and cooling cycles, as required to control the temperature of a conditioned space to a predetermined set point temperature. Heat from the liquid coolant is used to enhance the heating cycle. A heating cycle is initiated immediately, when required, when the temperature of the liquid coolant is above a predetermined temperature. A heating cycle is delayed by a special refrigeration cycle which increases the load on the prime mover, when the temperature of the liquid coolant is not above the predetermined temperature.

Abstract: A method of monitoring and protecting a transport refrigeration unit and a load in a load space to be conditioned by circulating air between the load space and the transport refrigeration unit. The transport refrigeration unit maintains a selected set point temperature SP in the load space by electrical control which selects cooling and hot gas heating conditioning modes initiated by switching a three-way valve between first and second positions. The method includes the step of detecting a reverse operating mode, wherein the actual conditioning mode is the opposite of the conditioning mode requested by the control means, and the step of pulsing the three-way valve in an attempt to cause the three-way valve, when stuck, to switch to the required position.

Abstract: A method of adding asynchronous logging of data relative to events into a time based data logger which stores operator initiated headers in a data array, as well as synchronously storing data relative to variables of a transport refrigeration unit at predetermined constant time intervals. The operator associated headers include a preamble having a predetermined number of data bytes which include a header designator and a digital code which identifies the specific type of header being entered. An event header is provided having a preamble which includes the same number of data bytes as the preamble of the operator associated headers, for each type of event to be asynchronously stored in the data array. The header designator associated with the operator associated headers is inserted into the preamble of each of the event headers. A digital code is provided which identifies each event header, and the digital code is inserted into the preamble of each of the event headers.

Abstract: Methods and apparatus for extending engine operating time, with a given amount of fuel, of an internal combustion engine connected to drive a compressor of a transport refrigeration unit. A fuel level signal is provided in response to the amount of fuel in a fuel tank associated with the internal combustion engine. The operation of the transport refrigeration unit is modified in different predetermined ways at predetermined different values of the fuel level signal, as fuel is consumed, to reduce the rate at which engine fuel is used after each modification. The time that a space being conditioned by the transport refrigeration unit for a given fuel supply is thus extended, maintaining temperature control of the conditioned space over this extended time while sacrificing non-load threatening, incremental degrees of control precision.

Abstract: A refrigeration unit, and method of operating same, having a compressor driven by a prime mover. The prime mover is selectively operable in either a continuous mode which includes heating and cooling cycles, or in start-stop cycling mode which includes cooling and null cycles, to control the temperature of a conditioned space relative to a predetermined set point temperature. In one embodiment, the cycle mode is operable only when the set point temperature is in a predetermined temperature range, the limits of which are selectable. The prime mover is operated in the continuous mode, notwithstanding the selection of the cycle mode, when the set point temperature is not within the temperature range authorized for cycle operation.

Abstract: A method of dynamically determining engine oil change intervals for an internal combustion engine having selectable high and low operating speeds HS and LS, respectively. The method includes the steps of accumulating operating time THS of the internal combustion engine at speed HS, accumulating operating time TLS of the internal combustion engine at speed LS, calculating a high speed factor HSF as a function of the accumulated engine operating time THS, and calculating a low speed factor LSF as a function of the accumulated engine operating time TLS. The method then sums the high speed and slow speed factors HSF and LSF to provide a sum S which is compared with a predetermined constant K1. A signal indicating the engine oil should be changed is provided when the comparison step finds the sum S has reached the predetermined constant K1.

Abstract: A refrigeration unit, and method of operating same, having a compressor driven by a prime mover. The prime mover is selectively operable in either a continuous mode which includes heating and cooling cycles, or in start-stop cycling mode which includes cooling and null cycles, to control the temperature of a conditioned space relative to a predetermined set point temperature. In one embodiment, the cycle mode is operable only when the set point temperature is in a predetermined temperature range, the limits of which are selectable. The prime mover is operated in the continuous mode, notwithstanding the selection of the cycle mode, when the set point temperature is not within the temperature range authorized for cycle operation.

Abstract: Methods and apparatus for monitoring conditions which may cause shut down of a refrigeration unit. When a condition of the refrigeration unit is detected which requires shut down, a shut down counter is incremented and the shut down is made with the provision for automatic restart of the refrigeration unit in response to predetermined parameters of the refrigeration unit. When the predetermined parameters initiate automatic re-start of the refrigeration unit, a timer is started. If the refrigeration unit operates for a predetermined period of time without shut down, the counting means is reset. A shut down before expiration of the predetermined timing period again increments the shut down counter. In one embodiment, when a predetermined condition which may cause shut down approaches a predetermined shut down value, the methods and apparatus modify the operation of the refrigeration unit one or more times in an attempt to prevent shut down.

Abstract: Methods and apparatus for checking the position and condition of a return air temperature sensor in a refrigeration system. The refrigeration system draws air from a served space in heat exchange relation with an evaporator coil, and discharges conditioned air into the served space, to maintain a predetermined set point temperature SP via selectable refrigeration cycles. The return air sensor provides a value RA responsive to the temperature of the air on the return side of the evaporator coil. A discharge air temperature sensor provides a value DA responsive to the temperature of the air on the discharge side of the evaporator coil, an evaporator coil temperature sensor provides a value ECT responsive to the temperature of the evaporator coil, and an ambient air temperature sensor provides a value AA responsive to the temperature of the ambient air.

Abstract: A method of starting and running an internal combustion engine connected to drive a refrigerant compressor in a refrigeration system which operates the engine at predetermined first and second speeds in response to a predetermined control algorithm, with the first speed being lower than the second speed. The method includes the step of starting and running the engine at the first speed, preventing switching from the first to the second speed in response to the control algorithm during an initial dynamic delay period following the step of starting the engine. The method then includes the step of determining the length of the initial dynamic delay period as a function of at least one predetermined parameter of the engine, and selecting the at least one predetermined engine parameter during the initial dynamic delay period.

Abstract: A .Iadd.system and .Iaddend.method .[.of.]. .Iadd.for .Iaddend.automatically starting and stopping an engine of a .[.truck.]. .Iadd.vehicle .Iaddend.to conserve fuel while maintaining the engine in a ready-to-start condition, and while controlling the temperature of .[.a truck sleeper unit.]. .Iadd.an interior portion of the vehicle.Iaddend.. The method includes the steps of selecting predetermined system parameters .[.via a password accessible interactive program, providing a first switch for selecting an automatic engine start-stop operating mode, providing a second switch for selecting an automatic temperature control mode for the truck sleeper unit, and providing safety apparatus which indicates when the truck engine may be safely operated in the automatic engine start-stop operating mode..]. The method further includes the step of overriding the .[.ignition switch.]. .Iadd.operator .Iaddend.control of the engine in response to a predetermined condition when .[.the.]. .Iadd.a .Iaddend.