Abstract: The invention is directed to regulating the conditioned space of an environment-controlled transport unit by identifying the product being conveyed as cargo in the conditioned space of a transport unit. A user can identify the cargo by selecting it from a menu of cargo identifiers. Once the cargo is identified, an environment control system retrieves from memory environment-control parameters as a function of the identified cargo, and regulates the environment of the conditioned space based upon the environment-control parameters.

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: In a transport temperature control system having a cooling and heating mode of operation an apparatus and method are provided for enhancing the heating capacity during the heating mode of operation. A second expansion valve is provided to connect the higher pressure liquid line to the refrigerant circuit downstream of the evaporator. When additional refrigerant is needed in the heating circuit to increase heating capacity, especially during low ambient temperature operating conditions, the second expansion valve is caused to open to admit more refrigerant to the system. After passing through the second expansion valve low pressure gas is passed to the compressor, optimizing compressor efficiency such that an increased amount of hot refrigerant gas is delivered to the evaporator for enhanced heating capacity.

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 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: 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 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 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: A transport refrigeration system having electrical control which controls the temperature in a served space via heating and cooling cycles using hot refrigerant gas from a refrigerant compressor. The refrigeration system has high and low pressure sides. The high pressure side includes a discharge manifold of the compressor, a condenser coil, a refrigerant receiver tank, and an evaporator coil associated with the served space. The low pressure side extends from the evaporator coil to a suction manifold of the compressor. A first controllable refrigerant flow path means is controlled by the electrical control to purge the condenser coil in response to predetermined system parameters, causing refrigerant trapped in the condenser coil to flow to the low pressure side of the system.

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: Methods and apparatus for monitoring and controlling the operation of a refrigeration unit in a manner which eliminates the need for circuit breakers and fuses in control circuits which are instrumental in selecting and changing the operational mode of the refrigeration unit. When a need to change to a different operating mode is detected, a controller energizes a control device associated with the different operating mode and quickly determines if the current draw is within an acceptable range. If the current draw is within an acceptable range or window, the controller initiates the requested different operating mode. If the current draw is not within the acceptable range, the controller generates an appropriate alarm and different courses of action are decided upon which depend upon whether the current draw is above or below the limits of the acceptable range, the nature of the requested operating mode, and the desired temperature of a space conditioned by the refrigeration unit.

Abstract: A method of monitoring a refrigeration unit including detecting premature return of air discharged into a conditioned space, and distinguishing this "short cycling" problem from a refrigeration capacity problem. The method includes determining the rates of change of the temperatures DA and RA of the discharge air and return air, respectively, during temperature pull down of the conditioned space, and comparing the rates of change with predetermined constants selected to detect a short cycling of the discharge air. When the rates of change do not fit a normal temperature pull down, the differential .DELTA.D between the temperatures DA and RA of the discharge air and return air is determined and compared with a third constant. Predetermined results of the comparisons of the rates of changes of DA and RA, and the temperature difference .DELTA.

Abstract: A method of operating a transport refrigeration system having a compressor driven by a prime mover at a selected one of high and low speeds, an evaporator, and an evaporator blower driven by the prime mover. Refrigeration control provides an error value which controls the temperature of a load space to a predetermined set point via heating and cooling modes. The method includes the steps of driving the compressor at high speed during pull down, and injecting hot gas into the evaporator when the error is reduced to a predetermined value. The prime mover is maintained at high speed, to keep evaporator air flow at a high rate, continuing a relatively rapid temperature pull-down across the entire load space. The speed of the prime mover is reduced to low speed when the error is further reduced to a second value, which also initiates suction line modulation while maintaining hot gas injection.

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.

Abstract: Methods and apparatus for detecting fuel problems of an internal combustion engine, including low fuel, a plugged fuel filter, a pinched fuel line, air in the fuel system, and gelled fuel. The detection of a fuel system problem is followed by engine shutdown, with shutdown being initiated quickly enough to retain sufficient fuel in the fuel system to re-start the engine without the necessity of priming. The invention includes the detection and counting of predetermined engine speed fluctuations. A timer is started upon the detection of the first predetermined speed fluctuation. If a predetermined count is reached before the timer reaches a predetermined time value, the engine is shutdown when the count is reached. If the timer reaches the time value before the count value is reached, the counter and timer are reset to await another predetermined engine speed fluctuation.

Abstract: A compartmentalized transport refrigeration system having refrigeration control, and interconnected host and remote refrigeration units for respectively conditioning the air in front and rear compartments of a trailer. The trailer has front and rear doors for access to the front and rear compartments, respectively, and a door switch connected to the refrigeration control which modifies the operation of the refrigeration system when the front access door is opened. When the front access door is opened, the host refrigeration unit is operated in null and the remote refrigeration unit is cycled between heating and cooling modes. A door switch may also be provided for the second access door which modifies the operation of the transport refrigeration system by effectively turning the remote refrigeration unit off.

Abstract: A transport refrigeration system having a compressor, condenser, receiver, and evaporator, for controlling the temperature of a served space via hot gas heating and cooling cycles. The receiver is selectively pressurized during a hot gas heating cycle, pressurizing the receiver at low ambient temperatures as sensed by compressor head pressure, and terminating or preventing receiver pressurization above a predetermined head pressure. This is useful for transport refrigeration systems which have a single compartment to condition, and it is even more useful in compartmentalized transport refrigeration systems having two or more compartments to condition.