Method for defrosting an external heat exchanger, which is operated as an air heat pump, of a cooling system for a motor vehicle, cooling system, and motor vehicle having such a cooling system

US11820203B2 · kind B2 · utility

Assignee

• AUDI AG · DE

Inventors

• Dirk Schroeder · Eckental, DE
• Christian Rebinger · Munich, DE
• Helmut ROTTENKOLBER · Mindelstetten, DE

Key dates

• Filing date: Dec 15, 2020
• Grant date: Nov 21, 2023
• Expiry date: Dec 15, 2040

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F25B2600/2519
• WIPO field: Thermal processes and apparatus
• WIPO sector: Mechanical engineering

Abstract

A method for defrosting an external heat exchanger, operated as an air heat pump evaporator, of a cooling system for a motor vehicle. The cooling system includes a refrigerant compressor connected to a primary and secondary section; an external heat exchanger; an evaporator; a heating register; a primary section valve which is closed in the air heat pump operation; and a secondary section valve which is open in the air heat pump operation. The method includes closing of the secondary section valve; opening of the primary section valve, so that refrigerant flows directly from the refrigerant compressor to the external heat exchanger; and setting an inlet-side pressure level of the refrigerant on the external heat exchanger to a target pressure which corresponds to a condensation temperature (Tkond) of the refrigerant in the range: 2° C.≤Tkond≤20° C., in particular 4° C.≤Tkond≤10° C.