Variable capacity compressor having a capacity control system using an electromagnetic valve

• US 5,199,855 A
• Filed: 06/27/1991
• Issued: 04/06/1993
• Est. Priority Date: 09/27/1990
• Status: Expired due to Fees

• Current Assignee: Zexel Corporation (Robert Bosch GmbH)
• Original Assignee: Zexel Corporation (Robert Bosch GmbH)
• Inventors: Yamaguchi, Toshio, Nakajima, Nobuyuki
• Primary Examiner(s): Smith, Leonard E.
• Application Number:
  US07/723,470
• Time in Patent Office: 649 Days
• Field of Search: 417/295, 417/310, 251/129.07
• US Class Current: 417/295
• CPC Class Codes: F04C 28/14 using rotating valves

Abstract

A variable capacity compressor comprises a control element for determining the timing of start of compression of refrigerant gas. Control pressure which acts on the control element to displace same between the minimum capacity position and the maximum capacity position is created in a high-pressure chamber by introducing discharge pressure thereinto. An electromagnetic valve opens and closes a passageway which commincates between the high-pressure chamber and a suction chamber by a pulse signal supplied from an ECU to control an amount of refrigerant gas leaking from the former into the latter to thereby control the level of the control pressure. The ECU makes the width of at least a first pulse or at least a first pulse base of the pulse signal wider than that of the following pulses or pulse bases, when the control element should start to be displaced between the minimum capacity position and the maximum capacity position. The control pressure is introduced to act on both ends of a valve body of the electromagnetic valve, whereby it is made possible to open the valve by a small driving force of an electromagnetic actuator thereof.

Claims

1. In a variable capacity compressor including a suction chamber, a discharging space within which discharge pressure prevails, a control element for determining timing of start of compression of a refrigerant gas, said control element having a pressure-receiving portion, a low-pressure chamber within which prevails suction pressure acting on said pressure-receiving portion of said control element, urging means cooperating with said suction pressure for urging said control element toward a minimum capacity position thereof, a high-pressure chamber within which prevails control pressure acting on said pressure-receiving portion of said control element for urging said control element toward a maximum capacity position thereof, high pressure-introducing passage means for introducing said refrigerant gas from said discharging space into said high-pressure chamber to create said control pressure therein, said high pressure-introducing passage means having a restriction hole for restricting flow of said refrigerant gas, a passage for communicating said high-pressure chamber with said suction chamber, a valve body for opening and closing said passage, a plunger, a coiled spring urging said valve body in a valve-closing direction through said plunger, and an electromagnetic actuator for magnetically attracting said plunger in a valve-opening direction against the urging force of said coiled spring,

the improvement wherein:

said valve body comprises a ball valve; and

passageway means is provided for applying said control pressure to one end of said ball valve of said valve body in said valve-opening direction, and at the same time for applying said control pressure to another end of said ball valve of said valve body in said valve-closing direction.

2. A variable capacity compressor according to claim 1, wherein said plunger has a transverse through hole formed therein for introducing said control pressure thereinto such that said control pressure acts to urge said ball valve of said valve body in said valve-closing direction through said plunger.