Denso Corporation

Toyota Jidosha Kabushiki Kaisha

Yoshikatsu Sawada

Yasutane Hijikata

Takeshi Wakisaka

Kazuma Miyazaki

Hiroyuki Nakaima

Kenta Kayano

Takashi Tanaka

Hiromasa Tanaka

Takekazu Kanou

A torque estimating device of a compressor for an ejector-type refrigerant cycle device includes a high pressure detector disposed to detect a physical amount having a relation with a high-pressure side refrigerant pressure of a refrigerant cycle, an evaporation pressure detector disposed to detect a physical amount having a relation with a refrigerant evaporation pressure in a suction side evaporator, a pressurizing estimating portion for estimating a pressurizing amount in a pressure increasing portion of an ejector to be increased in accordance with an increase of a pressure difference between the high-pressure side refrigerant pressure and the refrigerant evaporation pressure, and a suction pressure estimating portion for estimating a suction refrigerant pressure of the compressor by using the pressurizing amount estimated by the pressurizing estimating portion. Thus, a drive torque of the compressor can be accurately estimated in the ejector-type refrigerant cycle device.

Torque estimating device for compressor

A compressor drive torque estimating device to be adapted for a system provided with a refrigeration cycle in which a refrigerant is circulated by a compressor driven by a drive source mounted in a vehicle, comprising heat load detecting means for detecting a heat load of the refrigeration cycle, a storage unit storing a plurality of estimated drive torque characteristics establishing correlation between a drive torque change characteristic of the compressor and an elapsed time from a time of start of operation of the compressor, an estimated drive torque characteristic selecting means for selecting the one of the plurality of estimated drive torque characteristics stored in the storage unit based on detected values detected by the heat load detecting means, and an estimated drive torque calculating means for calculating an estimated drive torque of the compressor based on the estimated drive torque characteristic selected by the estimated drive torque characteristic selecting means.

Compressor driving torque estimating apparatus

A compressor inlet pressure estimation apparatus for a refrigeration cycle system is disclosed. An electronic control unitanswers YES by judging that the command to start a compressoris issued when an air-conditioning switch is turned on in step S. After that, the electronic control unitanswers NO in the case where a timer count time Tc is shorter than a predetermined time Tin step S. At the same time, Tefin_C is set to 15&#xb0; C. in step S. The lower one of Tefin_C and Tefin determined in this way is determined as Tefin_d (step S). After that, Tefin_d is input to the first-order lag function to acquire Tefin_AD(N). Then, the control proceeds to step S, where the estimated value Ps_es(N) of the refrigerant inlet pressure of the compressoris determined using Tefin_AD(N) and Gr.

Compressor inlet pressure estimation apparatus for refrigeration cycle system

A refrigeration cycle apparatus includes a compressor, a condenser, a pressure-reducing mechanism, an evaporator, an orifice provided in a refrigerant flow path from the compressor to the pressure-reducing mechanism, a differential pressure sensor that detects the differential pressure before and after the orifice, a refrigerant flowrate calculating portion that calculates a refrigerant flowrate based on the differential pressure, and a torque estimating portion that estimates the torque required to drive the compressor based on the refrigerant flowrate calculated by the refrigerant flowrate calculating portion, the intake pressure of the compressor, and the discharge pressure of the compressor.

Refrigeration cycle apparatus

A refrigeration cycle system is disclosed. A compression unitfor compressing the refrigerant by the drive force of a vehicle engineis arranged in a housingof a compressor. The flow rate of the refrigerant discharged from the compression unitis detected by a flow rate sensorincluding a throttle portionand a pressure difference detection mechanism. The throttle portionreduces the flow rate of the refrigerant discharged from the compression unit. The pressure difference detection mechanismdetects the pressure difference between the upstream side and the downstream side of the throttle portionin the refrigerant flow thereby to detect the flow rate of the refrigerant discharged from the compression unit. An oil separatorfor separating the lubricating oil from the refrigerant discharged from the compression unitis interposed between the compression unitand the flow rate sensor

Refrigeration cycle system

A compressor inlet pressure estimation apparatus for a refrigeration cycle system is disclosed. An electronic control unituses Tefin_lag(N) as an actual corrected temperature Tefin_AD(N) during a period Tpincluded in the timing tto t. During a period Tpincluded in the timing tto t, Tefin_fwd(N) is used as the actual corrected temperature Tefin_AD(N). Thus, a highly accurate corrected temperature Tefin_AD(N) can be determined over the on period (tto t) of a compressor. In addition, Tefin_fwd(N) is used as the actual corrected temperature Tefin_AD(N) during the off period (tto) of the compressor. As a result, a highly accurate corrected temperature Tefin_AD(N) can be determined over the whole period including the on and off periods of the compressor. In this way, a highly accurate estimated value Ps_es(N) of the refrigerant inlet pressure of the compressorcan be determined.

A refrigerant cycle device includes a compressor driven by a vehicle engine for drawing and compressing gas refrigerant from an evaporator, a variable displacement mechanism which varies a discharge capacity of the compressor based on a control value from an exterior to approach a suction pressure of the compressor to a predetermined suction pressure, and a control unit for controlling the discharge capacity of the compressor. The control unit includes a determining part for determining an accelerating state of the vehicle engine, a detecting member which detects a thermal load of the evaporator, a setting part for setting a minimum control value in accordance with the thermal load, and a controlling part. The controlling part reduces the control value to the minimum control value and returns the reduced control value to a control value before the reducing, when the determining means determines an accelerating state of the vehicle engine.

Refrigerant cycle device and control system for vehicle

A compressor drive torque estimating device suppresses a discrepancy between an estimated drive torque, which is based on a torque estimating device of a compressor, and an actual drive torque of the compressor. The discrepancy is due to delay in switching between employment of the torque estimating device and the actual drive torque of the compressor in judging the compressor torque. Thus, even in a transitional state immediately after the start of compression, the idling speed of an engine driving the compressor is controlled based on an accurate estimate of the compressor torque, to improve the stability of the engine idle speed.

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Kariya, Japan

Yoshikatsu Sawada