Vacuum power system and regulator therefor

• US 4,328,669 A
• Filed: 02/15/1980
• Issued: 05/11/1982
• Est. Priority Date: 02/15/1980
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Mort, Dewey F.
• Primary Examiner(s): Ostrager, Allen M.
• Assistant Examiner(s): Husar, Stephen F.
• Application Number:
  US06/121,671
• Time in Patent Office: 816 Days
• Field of Search: 60/397, 60/721, 60/407, 60/409, 60/421, 123/198 R, 180/175, 180/177, 91/28, 91/29, 91/514, 91/517
• US Class Current: 60/397
• CPC Class Codes: B60K 25/00 Auxiliary drives B60K16/00 takes precedence; arrangements of tyre-inflating pumps mounted on vehicles B60C23/10; driving tyre-inflating pumps B60C; driving engine auxiliaries F02B
• CPC Class Codes: B60K 25/04 from static or dynamic pressure or vacuum, developed by the engine
• CPC Class Codes: B60K 31/06 including fluid pressure actuated servomechanism in which the vehicle velocity affecting element is actuated by fluid pressure
• CPC Class Codes: B60T 13/52 indirect, i.e. vacuum booster units
• CPC Class Codes: B60T 17/02 Arrangements of pumps or compressors, or control devices therefor
• CPC Class Codes: B60T 17/18 Safety devices; Monitoring

Abstract

A vehicle vacuum power system which insures sufficient vacuum power to operate a vacuum brake booster and a vacuum operated road speed control system. Because of the low vacuum, high flow rate needs of a cruise control system, the cruise control is connected directly to the engine manifold through a check valve. A small orifice from the vacuum pump in parallel with engine manifold vacuum provides sufficient vacuum for the cruise control when the manifold vacuum is not sufficient. The vacuum pump is in series with manifold vacuum and is operated in response to a pressure switch which allows the pump to run only when brake booster vacuum is low. Manifold vacuum is sufficient most of the time, but the orifice to the cruise control tends to cause a fast loss of brake booster vacuum, causing the vacuum pump to run when it is not actually needed. The vacuum regulator shuts off the flow through the orifice when it is not needed, considerably reducing the pump operational time. The regulator is a two-piece housing with a spring loaded diaphragm controlling a regulator port. Atmospheric pressure is on one side of the diaphragm and engine manifold vacuum is on the other.

Claims

1. A vacuum power system having first and second devices operable by vacuum power and first and second sources of vacuum power, said first source when operating normally providing sufficient vacuum power to operate said first device and said second source providing sufficient vacuum power to operate said second device, said second source being variably operable to maintain the vacuum operating level required by said second device;

means sensing the lack of sufficient vacuum power from said first source to operate said first device when such lack occurs, said means then acting to communicate sufficient vacuum power from said second source to said first device to operate said first device;

and means responsive to changes in vacuum level provided from said second source as vacuum power therefrom is used to cause said second source to be operated variably as needed to maintain at least sufficient vacuum power to operate said first and second devices.

2. A vacuum power system having first and second devices operable by vacuum power, a vacuum power reservoir and first and second sources of vacuum power, said first source when operating normally providing sufficient vacuum power to operate said first device, said second source being variably operable to maintain a reservoir of vacuum power in said vacuum power reservoir at the vacuum operating level required by said second device;

means sensing the lack of sufficient vacuum power from said first source to operate said first device when such lack occurs, said means then acting to communicate sufficient vacuum power from vacuum power reservoir and said second source to said first device to operate said first device;

and means responsive to changes in vacuum level provided from said second source as vacuum power therefrom is used to cause said second source to be operated variably as needed to maintain at least sufficient vacuum power to operate said first and second devices.

3. A subatmospheric pressure power system comprising:

an engine intake providing a first source of subatmospheric pressure when the engine is operating;

a vacuum pump having an inlet and an outlet and providing a second source of subatmospheric pressure and being selectively operable to maintain subatmospheric pressure within a predetermined range at the pump inlet, said pump outlet being in communication with said engine intake to decrease the pressure differential across said pump when said engine intake and said pump are operating to provide subatmospheric pressure;

a vacuum suspended brake booster connected to said pump inlet to receive subatmospheric pressure from said pump;

vacuum pump control means sensing the subatmospheric pressure values supplied to said brake booster from said pump and operable to cause said pump to be operated when the sensed subatmospheric pressure value reaches a first predetermined value and to cause said pump to cease operation when the sensed subatmospheric pressure value reaches a second predetermined value;

a vehicle road speed control operated by subatmospheric pressure when operating and requiring a predetermined value of subatmospheric pressure;

and a subatmospheric pressure regulator having a subatmospheric pressure chamber, a first port opening into said chamber and receiving subatmospheric pressure from said engine intake, a second port opening into said chamber and receiving subatmospheric pressure from said pump inlet, a third port opening into said chamber and connected to said vehicle road speed control to supply subatmospheric pressure thereto, and means responsive to subatmospheric pressure in said chamber and to atmospheric pressure and, upon the occurrence of a predetermined minimum pressure differential therebetween which is numerically slightly greater than the value of the subatmospheric pressure required to operate said road speed control, acting to communicate pump inlet subatmospheric pressure to said regulator chamber to assure the presence of sufficient subatmospheric pressure to operate said road speed control, said means closing said second port and preventing communication of pump inlet subatmospheric pressure to said regulator chamber when said engine intake is providing sufficient subatmospheric pressure at said regulator first port and in said chamber and at said third port to operate said road speed control.