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:
Jun. 30, 1992
Filed:
Apr. 12, 1991
Udo Frinzel, Grunthal, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
A tank ventilation system for an internal combustion engine includes a lambda control device and an intake section communicating with the engine; a throttle valve in the intake section and air flow rate meter in the intake section for determining a flow rate of air aspirated by the engine; a tank communicating with a reservoir for holding fuel vapors; a scavenging line communicating between the reservoir and the intake section downstream of the throttle valve to be scavenged by means of a scavenging air mass; a tank ventilation valve in the scavenging line for controlling the scavenging air mass; a control unit for triggering the tank ventilation valve during a scavenging event in given operating states of the engine; and a delivery line communicating between the reservoir and the intake section between the throttle valve and the air flow rate meter for delivering the scavenging air mass to the reservoir. A method for operating the system includes opening the tank ventilation valve with the control unit during a first scavenging event after starting the engine, resulting in a lambda deviation d.lambda.; measuring a scavenging air flow rate Q with the air flow rate meter; and calculating a scavenging fuel flow rate K from the lambda deviation d.lambda. and the scavenging air flow rate Q as a measure of the loading of the reservoir, according to the equation K=Q/d.lambda.. The method may also include checking upon each triggering of the tank ventilation valve whether or not the air flow rate measured by the air flow rate meter varies accordingly, and generating a defect signal if the measured air flow rate does not vary accordingly.