摘要:
A method of operating a transport refrigeration system having a refrigerant compressor driven by an internal combustion engine. Microprocessor based electrical control maintains the temperature of a conditioned space at a desired set point via heating, cooling and null cycles, with the engine being started and stopped, as required. During the engine starting process, a suction line modulation valve, if used, is closed, engine pre-heat time is selected, including using engine temperature to access a look-up table, and current draw is checked during pre-heat. Excessive current terminates pre-heat. Control diagnostics checks the voltage level on both sides of a refrigerant high pressure switch, before initiating engine cranking. Prior to stopping the engine, a control option initiates a heating cycle for a short time when null is being entered from a cooling cycle, to warm the evaporator and prevent premature starting of the engine.
摘要:
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.
摘要:
A transport refrigeration system having a refrigerant compressor which is selectively operable with either an electric motor or an internal combustion engine. The transport refrigeration system conditions a load space to a selected set point via heating and cooling modes in response to a selected one of either a return air sensor or a discharge air sensor. System control is automatically optimized in response to manual selections of the prime mover and the operative sensor by providing first, second, third and fourth control algorithms. Selection of the return air sensor automatically selects the first and third control algorithms for electric motor and internal combustion engine, respectively, and selection of the discharge air sensor automatically selects the second and fourth control algorithms for the electric motor and internal combustion engine, respectively.
摘要:
A refrigeration system having a modulation valve which controls refrigerant flow to a compressor according to a control algorithm. The need for a compressor throttling valve is eliminated by a load control circuit which operates the modulation valve to perform the function of the throttling valve when load reduction is required. An overload condition of a compressor prime mover overrides the control algorithm and selects a predetermined load control position of the modulation valve. A timer ensures that a predetermined recovery time is provided, before switching back to the control algorithm. The timer also selects the load control position of the modulation valve upon start-up. A heating or defrost mode automatically selects the load control position of the modulation valve for the duration of the mode, as does an ambient air temperature sensor when the ambient exceeds a predetermined value.
摘要:
A ratiometric temperature controller for a transport refrigeration system, and a method of controlling the load temperature of a transport refrigeration system with digital signals provided in response to an analog ratio between the load temperature and a selected set point temperature. A logic array is programmed to provide a plurality of transport refrigeration system control signals in response to predetermined values of the digital signal. The resolution of the control is increased by having the digital signal respond to a temperature range relatively close to set point, which is a much smaller range than the temperature range over which the set point may be selected. The logic array will respond to a forcing signal which, when true, indicates the need for a high speed cooling mode, when the load temperature is above set point and the system is already in a cooling mode.
摘要:
A ratiometric temperature controller for a transport refrigeration system, and a method of controlling the load temperature of a transport refrigeration system with digital signals, without the necessity of utilizing a digital computer. The method, implemented by the ratiometric controller, includes the steps of providing an analog ratio between the load temperature and a selected set point temperature, converting the analog ratio to a digital signal, and providing a logic array which is programmed to provide a plurality of transport refrigeration system control signals in response to predetermined values of the digital signal.
摘要:
The tips 14 of any glow plugs 10 which are shorted are protected against enlargement by a separate protective device 28 in each series connection 26 to an individual glow plug opening in a fraction of a second in response to current through the device of a value corresponding to a short of the heating element in the tip.
摘要:
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.
摘要:
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.
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.