An air conditioning refrigerant circuit (6) includes an engine-driven compressor (7) and an electric compressor (11), which are arranged in parallel. When the engine is running, the engine-driven compressor (7) is used. When the engine stops, e.g., when idling stops, the electric compressor (11) is used. At the startup of the engine by a manual operation such as ignition by a key, the engine-driven compressor (7) is kept at rest and instead, the electric compressor (11) is operated for a predetermined time. After the predetermined time, the engine-driven compressor (7) is operated. In this way, the oil recovery to the electric compressor is promoted.

Disclosed are climate systems and methods for control the climate systems. A climate system includes a plurality of compressors, a first heat exchanger disposed downstream of the compressors and a second heat exchanger disposed downstream of the first heat exchanger. The compressors and heat exchangers are fluidly connected by refrigerant lines to form a refrigerant circuit. The climate system also includes a controller that controls the operation of the compressors to draw back lubricant to the compressors without use of an oil equalization system.

Disclosed are climate systems and methods for control the climate systems. A climate system includes a plurality of compressors arranged in parallel, a condenser disposed downstream of the compressors and an evaporator disposed downstream of the condenser. The compressors, the condenser, and the evaporator are fluidly connected by refrigerant lines to form a refrigerant circuit. The climate system also includes a controller that controls the operation of the compressors to draw back lubricant to the compressors without use of an oil equalization system.

Methods and system for managing lubricant within a vapor compression heat pump are presented. In one example, lubricant may be flushed from selected areas of a heat pump to other areas of the heat pump where lubricant is desired. The lubricant may be flushed in full flushing mode or in a partial flushing mode.

A method for controlling an air conditioner compressor includes: driving the air conditioner compressor for a first time at a first revolutions per minute (RPM) smaller than a minimum lubrication demand RPM when a lubrication demand RPM of the air conditioner compressor is smaller than the minimum lubrication demand RPM; and driving the air conditioner compressor for a second time at the minimum lubrication demand RPM when the lubrication demand RPM of the air conditioner compressor is smaller than the minimum lubrication demand RPM after the first time elapse.

Disclosed are climate systems and methods for control the climate systems. A climate system includes a plurality of compressors arranged in parallel, a condenser disposed downstream of the compressors and an evaporator disposed downstream of the condenser. The compressors, the condenser, and the evaporator are fluidly connected by refrigerant lines to form a refrigerant circuit. The climate system also includes a controller that controls the operation of the compressors to draw back lubricant to the compressors without use of an oil equalization system.

A compressor compresses a refrigerant. A eutectic plate cools a refrigerated space. An evaporator cools the refrigerated space. A mixture of the refrigerant and an oil flows through the evaporator and the eutectic plate. A control module controls the compressor, a first valve that permits or prevents flow of the mixture to the eutectic plate, and a second valve that permits or prevents flow of the mixture to the evaporator. In response to a temperature of the refrigerated space being greater than a predetermined temperature, the control module: increases a speed of the compressor; operates the compressor at the increased speed for a predetermined time period; after the predetermined period: opens the second valve; and closes the first valve, where the control module opens the second valve before closing the first valve, and decreases the speed of the compressor after closing the first valve.

An air conditioning refrigerant circuit (6) includes an engine-driven compressor (7) and an electric compressor (11), which are arranged in parallel. When the engine is running, the engine-driven compressor (7) is used. When the engine stops, e.g., when idling stops, the electric compressor (11) is used. At the startup of the engine by a manual operation such as ignition by a key, the engine-driven compressor (7) is kept at rest and instead, the electric compressor (11) is operated for a predetermined time. After the predetermined time, the engine-driven compressor (7) is operated. In this way, the oil recovery to the electric compressor is promoted.

A compressor control method, including: when driving of a compressor of a vehicular air conditioner starts, a determining step of determining whether a condition for limiting an output of the compressor is satisfied by using at least one among whether a power supply unit of a vehicle is reset, a start-off period and the number of times the compressor is driven; an output limiting step of limiting an output of the compressor when the condition for limiting the output of the compressor is satisfied; a third determining step of determining an output limiting driving time of the compressor driven in a state in which the output is limited by the output limiting step; a normal driving step of canceling the output limitation of the compressor and normally driving the compressor when the output limiting driving time of the compressor is equal to or greater than a predetermined reference time.

Disclosed are climate systems and methods for control the climate systems. A climate system includes a refrigerant circuit, a first compressor, a second compressor, a first refrigerant-to-air heat exchanger, a second refrigerant-to-air heat exchanger, and a controller communicatively coupled to the first and second compressors. Respective outlets of the first and second compressors are fluidically coupled to the first refrigerant-to-air heat exchanger, the first refrigerant-to-air heat exchanger is fluidically coupled to the second refrigerant-to-air heat exchanger, and the second refrigerant-to-air heat exchanger is fluidically coupled with respective inlets of the first and second compressors. The fluidic connection between the second refrigerant-to-air heat exchanger and the first and second compressors includes a vertical split that is configured to mitigate or reduce the amount of compressor oil that migrates to dormant components.