Means and method for operating evaporative emission system leak detection pump
US5499614A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 1994 |
| Grant date | Mar 19, 1996 |
| Priority date | — |
| Expiry date | Nov 3, 2014 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M25/0809
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An on-board diagnostic system for an evaporative emission control system of an internal combustion engine powered vehicle employs a positive displacement reciprocating pump to create in evaporative emission space a pressure that differs significantly from ambient atmospheric pressure. The pump is powered by using engine intake manifold vacuum to force an intake stroke during which both an internal spring is increasingly compressed and a charge of ambient atmospheric air is created in an air pumping chamber space. Vacuum is then removed, and the spring relaxes to force a compression stroke wherein a portion of the air charge is forced into the evaporative emission space. The pump operation is under the control of a computer that contains an algorithm for operating the pump in particular modes of operation to arrive at a decision concerning integrity of the evaporative emission space against leakage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.