The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 12, 2000
Filed:
Nov. 12, 1998
Barry J Lake, Troy, MI (US);
Lawrence Ziehr, Holland, OH (US);
Lance C Tagliapietra, Winona, MN (US);
DaimlerChrysler Corporation, Auburn Hills, MI (US);
Abstract
A reversible HVAC system for heating a passenger compartment of a motor vehicle is disclosed. The HVAC system includes a heat pump and an electric heater for supplying heat directly to air blown into the passenger compartment. A controller initially selects the heat pump to provide the heat that is directed into the passenger compartment. The heat pump attempts for a predetermined period of time to heat the passenger compartment to a target temperature. The controller stores a heat pump gain value representing the heating capacity of the heat pump before switching the heating operation to the electric heater. During operation of the electric heater, the controller calculates a system heat gain value representing the required heating capacity to maintain the passenger compartment at the target temperature. While the electric heater is operating, the controller continuously modifies the heat pump gain value to reflect changes in the ambient temperature. When the heat pump gain value approximately equals or exceeds the system gain value the controller selects the heat pump to provide heating.