摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A method of monitoring a transport refrigeration system which is effective regardless of the temperature of a served space relative to a selected set point temperature. Different "windows" of acceptable and marginal performance are provided in the form of different minimum magnitudes of .DELTA.T, i.e., the algebraic difference between the return and discharge air temperatures, as a function of ambient and return air temperatures. The transport refrigeration system is thus monitored at all times, during both cooling and hot gas heating modes, and also including during initial temperature pull down of the cargo space, enabling an early warning to be generated for a marginal performance, and an early shut down to be initiated for unacceptable performance. In a preferred embodiment, a maximum value of .DELTA.T is also provided, which, if exceeded by the actual .DELTA.T, indicates a restricted air flow in the cargo space.
摘要:
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. A predetermined count value on the shut down counter prevents further automatic re-starts of the refrigeration unit. In a preferred embodiment, the monitored conditions which may cause shut down are the high side pressure of the refrigeration unit, and, when a refrigerant compressor is driven by an internal combustion engine, the temperature of the engine.
摘要:
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. A data field follows the preamble of each event header, with predetermined data being inserted into the data field when an event occurs. An event header is stored in the data array asynchronously, at the time the associated event occurs. Each event header is time stamped when stored in the data array, and data stored in the data array is downloaded to a predetermined device, including asynchronously stored event headers and synchronous data stored at predetermined time intervals.
摘要:
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. In a preferred embodiment, the method also includes the step of detecting when the engine oil of the internal combustion engine has been changed, and the step of resetting the accumulated high and low speed operating times THS and TLS, respectively, when the detecting step detects that the engine oil has been changed.
摘要:
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.