Thermo King Corporation

Gerald J Ladendorf

Jay L Hanson

Doyle G Herrig

James E Nixon

Rodney H Volk

Lowell B Naley

Donald G Knauff

Norman F Spear

A refrigerated mobile trailer is provided that includes a trailer body having an opening present in both its front wall and roof for receiving a transportable refrigeration unit. The refrigeration unit includes a housing having a roof panel and a side panel, a condenser assembly disposed within the housing that includes a condenser coil, an air inlet located in the side panel of the unit housing for receiving ambient air for circulation over the condenser coil and at least one air outlet for discharging circulated air to remove waste heat from the coil. The condenser coil is located adjacent to the roof panel of the refrigeration unit, and all air outlets for removing waste heat from the coil are advantageously located in the unit roof panel directly above the coil. The fact that all of the waste heat air outlets are located in the roof panel advantageously prevents air discharged from these outlets from recirculating back into the condenser air inlet when the mobile trailer is in a stationary position. Such a component arrangement also provides more useable space within the unit housing, which may be used to reduce the unit extension beyond the trailer front wall by 17%.

Condenser and radiator air outlets

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. In other embodiments, the time duration and the upper temperature limit of the null cycle are both selectable, with an automatic override of the selected upper temperature limit being provided when the conditioned space contains a frozen load and the selected upper temperature limit of the null cycle would allow the temperature of the conditioned space to rise above a predetermined value. In still other embodiments, in which the prime move includes an engine and a battery, the minimum battery voltage which will re-start the engine to terminate a null cycle, and the minimum battery charging current which will enable the engine to be stopped to initiate a null cycle, are both selectable.

Refrigeration unit and method of operating same

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.

Method of starting and running an internal combustion engine connected

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.D with the first, second and third constants, respectively, are utilized to identify proper air flow in conditioned space, to indicate a problem with air flow in conditioned space, and to indicate that refrigeration capacity should be checked.

Method of detecting short cycling of air discharged by a refrigeration

A method of operating a refrigeration system having a compressor driven by an engine, with the refrigeration system being operable in a first control mode to hold the temperature of a conditioned space at a selected set point temperature, and in a second control mode to maintain the engine in a ready-to-start condition. The second control mode includes monitoring the ambient temperature, and determining a dynamic set point temperature as a function of ambient temperature. The engine is started and stopped to maintain engine startability, and also as a function of the dynamic set point temperature, to maintain the temperature of the conditioned space at the dynamic set point temperature while maintaining the engine in a ready-to-start condition. Control is changed from the second to the first control mode, when a programmed start feature is activated, with the time of such mode change being a function of the difference between the ambient temperature and the selected set point temperature.

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Bloomington, MN, United States of America

Gerald J Ladendorf