Abstract: The compressor of a transport refrigeration system is divided into two sections, with each section having a suction inlet. The refrigerant vapor from the evaporator is passed to one of the suction inlets, whereas the refrigerant vapor from a subcooler circuit is passed to the other suction inlet. A valve is operated to selectively insert or remove the subcooler as capacity requirements vary. In one embodiment, a six cylinder reciprocating compressor is used with five cylinders compressing within a first section, and a single cylinder compressing in the other section containing the subcooler circuit.

Abstract: A process and method for monitoring and selectively controlling the capacity and power demand within a transport unit is disclosed. Specifically, the present invention teaches the combined controls of an electronic suction modulation valve, and electronic expansion valve, and/or an electronic hot gas valve in communication with a microcontroller and a number of sensors in order to monitor and control power consumption and capacity, preferably without the use or presence of compressor unloaders, mechanical throttling devices, or other mechanical power control devices.

Abstract: A method and apparatus for changing operational modes of a transport refrigeration unit, where the unit is capable of operating in a continuous heating/cooling mode or an automatic start/stop heating/cooling mode. A supply air temperature sensor measures the temperature of the air exiting the unit, a return air temperature sensor measures the temperature of the air returning to the unit, and an ambient air temperature sensor measures the temperature of the ambient air outside the unit. A controller electrically connected to the sensors determines if the ambient air temperature is above or below a pre-determined setpoint temperature, determines if the temperature differential across the return and supply air sensors is above or below a pre-determined upper threshold or a pre-determined lower threshold, and then changes the operational mode of the unit based upon such determinations and the prior operational mode of the unit.

Abstract: A method for controlling oil viscosity in a refrigeration unit having an oil viscosity effecting parameter with a desired set point. The refrigeration unit includes an oil lubricated compressor having a capacity and a suction pressure, a condenser, refrigerant control valves, and an evaporator connected in series, for circulating a refrigerant for adjusting air temperature of a compartment.

Abstract: A method and apparatus for changing operational modes of a transport refrigeration unit, where the unit is capable of operating in a continuous heating/cooling mode or an automatic start/stop heating/cooling mode. A supply air temperature sensor measures the temperature of the air exiting the unit, a return air temperature sensor measures the temperature of the air returning to the unit, and an ambient air temperature sensor measures the temperature of the ambient air outside the unit. A controller electrically connected to the sensors determines if the ambient air temperature is above or below a pre-determined setpoint temperature, determines if the temperature differential across the return and supply air sensors is above or below a pre-determined upper threshold or a pre-determined lower threshold, and then changes the operational mode of the unit based upon such determinations and the prior operational mode of the unit.

Abstract: An engine starter has a plunger electromagnetically actuated by holding and attracting coils to move a pinion toward a ring gear on the engine and also to move a first movable contact on the plunger towards first and second stationary contacts to be electrically connected together by the first movable contact to electrically energize a starter motor. Completion of the circuit between the movable contact and the stationary contacts also serves to de-energize the attracting coil which may be damaged if energized for too long. Control means are provided to determine the voltages at each of the fixed contacts. The difference between the monitored voltages is determined and compared to a reference voltage differential. If the difference is not less than or equal to the reference voltage differential, the controller is programmed to know that the circuit has not been completed, and in order to avoid damage to the attracting coil and the starter, power is interrupted to the starter circuit.

Abstract: A transport refrigeration system of the type which holds a set point temperature by way of heating and cooling cycles. A compressor discharge temperature control circuit is provided which senses the temperature of the hot compressor discharge gas and controls a flow of liquid refrigerant directly into the compressor suction line responsive to the sensed temperature. The receiver of the system is provided with hot gaseous refrigerant to thereby force liquid refrigerant therefrom which supplies the discharge temperature control circuit in all modes of operation.

Abstract: A transport refrigeration system of the type which holds a set point temperature via heating and cooling cycles. The system includes a refrigerant circuit which includes a compressor, condenser, receiver, evaporator, and a mode selection means for selectively directing hot compressed refrigerant gas to the condenser, or, through a hot gas conduit to the evaporator. The system includes a prime mover, typically a diesel engine for driving the compressor. The system includes a first hot gas flow control means having a predetermined, limited, refrigerant flow capability for controlling the flow of refrigerant therethrough. It further includes a second hot gas flow means having a refrigerant flow capability which is substantially greater than the predetermined limited refrigerant flow capability of the first hot gas flow control means. The first and second hot gas flow control means are disposed in parallel fluid flow relationship in the hot gas conduit.

Abstract: An oil separator is provided for separating oil from a refrigerant gas and returning the oil to a compressor. The separator includes a housing which has means associated therewith for conducting a mixture of refrigerant gas and oil into the housing and therein separating the oil from the gas. The separated oil is stored in a reservoir forming a part of the housing. A plurality of oil pickup devices are located within the oil reservoir. Each of the oil pickup devices has an oil pickup opening associated therewith. The oil pickup openings are located at different depths within the oil reservoir. The pickup devices are designed so that they are substantially more receptive to the flow of lubricating oil therethrough than to the flow of refrigerant gas. In one embodiment, the oil pickup devices are capillary tubes having their open ends located at different depths within the oil reservoir.

Abstract: An internally compounded two-stage compressor has an interstage cooler and an oil separator associated therewith. The oil, and any hot gas mixed with it, discharged from the oil separator is passed in heat exchanger relationship with the cooling refrigerant flowing into the interstage cooler.

Abstract: A bulkhead formed of nesting channels connected together with toggle arms. The channels are attached to the forward wall of a refrigerated trailer and form a barrier to protect a refrigeration unit and provide an unrestricted air passage duct for return air. A channel shaped outboard extending support member swivels on toggle arms and due to its overcenter arrangement, remains extended vertically. When the outboard member is rotated upwardly, the channels and toggles nest together decreasing the depth of the apparatus. The collapsed position is maintained by several spring retaining clips that grasp a toggle arm connecting member.In another embodiment the channels are connected together with a solid partition which is positioned above the floor and below the air discharge opening of a refrigeration unit.