David A Barwin

US Patent:

60890347, Jul 18, 2000

Filed:

Nov 12, 1998

Appl. No.:

9/190472

Inventors:

Barry J. Lake - Troy MI
David A. Barwin - Troy MI
Richard Harris - Holly MI
Lance C. Tagliapietra - Winona MN

Assignee:

DaimlerChrysler Corporation - Auburn Hills MI

International Classification:

F25B 4104
F25B 100

US Classification:

62204

Abstract:

A control system for controlling a reversible HVAC system of a motor vehicle is disclosed. The HVAC system includes an electric compressor for circulating a refrigerant through a heat pump. The speed of the compressor is controlled by a compressor control signal having a variable duty cycle. Inside and outside heat exchangers transfer heat energy between an outside environment and a passenger compartment of the motor vehicle. A refrigerant flow switching device switches the direction of refrigerant flow towards the inside heat exchanger in a heating mode and towards the outside heat exchanger in a cooling mode. A pressure reducing assembly supplies pressure reduced refrigerant to the inside heat exchanger in the cooling mode and to the outside heat exchanger in the heating mode. The pressure reducing assembly includes an electronic expansion valve in which the flow rate is set by an EXV control signal having a variable duty cycle. A controller controls the duty cycle setting of the compressor control signal and the EXV control signal such that a desired quantity of heat is transferred between the outside environment and the passenger compartment.

US Patent:

53355148, Aug 9, 1994

Filed:

Jun 1, 1993

Appl. No.:

8/071147

Inventors:

Robert P. Hennessee - Rochester Hills MI
David A. Barwin - Troy MI
Robert G. Rudzewicz - Sterling Heights MI
Richard M. Rajala - Auburn Hills MI

Assignee:

Chrysler Corporation - Highland Park MI

International Classification:

B60H 300

US Classification:

62227

Abstract:

A method and software/firmware fixed capacity compressor control system for varying the set point temperature of a evaporator in response to changes in ambient temperature in order to produce optimum cooling in the passenger compartment of a vehicle while preventing frost from accumulating on the fins of the evaporator. The system includes an evaporator probe and an outside ambient sensor and firmware for computing set-point steady state temperatures values over a wide range of ambient temperature. Also circuits are provided for cycling ON and OFF a fixed capacity compressor in a manner to achieve optimum cooling in the passenger compartment of the vehicle in response to the computed evaporator set point temperatures.

US Patent:

54676053, Nov 21, 1995

Filed:

Apr 26, 1995

Appl. No.:

8/432456

Inventors:

Robert P. Hennessee - Rochester Hills MI
Gary B. Flaishans - Clarkston MI
Robert G. Rudzewicz - Sterling Heights MI
David A. Barwin - Troy MI

Assignee:

Chrysler Corporation - Highland Park MI

International Classification:

F25D 2104

US Classification:

62133

Abstract:

A system for preventing fogging in air conditioning systems is disclosed. The system employs a strategy whereby if fogging conditions are present, the temperature of the evaporator is stepped downwardly in increments which allow the surface of the evaporator to stabilize thereby eliminating localized cold spots.

US Patent:

60821280, Jul 4, 2000

Filed:

Nov 12, 1998

Appl. No.:

9/190925

Inventors:

Barry J. Lake - Troy MI
David Cleveland - Azle TX
David A. Barwin - Troy MI
Robert Bandeen - Dallas TX
Arthur A. Naujock - Livonia MI

Assignee:

DaimlerChrysler Corporation - Auburn Hills MI

International Classification:

F25B 1300

US Classification:

623246

Abstract:

A pressure reducing assembly is provided for managing refrigerant flow in a reversible HVAC system. Refrigerant lines from the system heat exchangers connect to bi-directional ports of a pressure reducing assembly which converts the high pressure refrigerant flowing from one heat exchanger into pressure reduced refrigerant that flows to the other heat exchanger. The pressure reducing assembly converts bi-directional refrigerant flow from the heat exchangers into unidirectional refrigerant flow through a pressure reducing device. Refrigerant emitted from the pressure reducing device flows out of the pressure reducing assembly to the other heat exchanger. The invention simplifies the interconnection of reversible HVAC systems by eliminating the complex plumbing and extra valves associated with conventional systems. In addition, the invention can further integrate the receiver/drier function into the pressure reducing assembly providing a centralized device for filtering refrigerant flow and ensuring a continuous supply of liquid refrigerant to the pressure reducing device. Also, outlets can be added to the receiver portion of the pressure reducing assembly to provide a source of high pressure liquid refrigerant for secondary heat exchangers.