Method of determining the purge canister mass
First Claim
1. A method determining a canister purge vapor flow condition in an evaporative emissions control system comprising:
- learning a purge valve mass flow rate;
learning a fuel tank mass flow rate; and
combining said purge valve mass flow rate with said fuel tank mass flow rate to yield a net mass flow to the canister.
20 Assignments
0 Petitions
Accused Products
Abstract
A method is provided for accommodating the purge vapors from an evaporative emission control system of an automotive vehicle. The method includes a means of learning changes in the mass of a purge vapor collection canister such that a mass of purge vapor in the canister can be determined. The canister model uses the output of a strategic adaption routine to learn the loading of the canister. Thereafter, the canister model uses the learned loading of the canister and tank flow rate from a tank model to compute the mass balance of purge vapor exiting and entering the canister. The concentration level is compared to the calibrated maximum in an open loop surface to determine the level of canister loading. Based on the current loading of the canister, the open loop surface of canister concentration as a function of flow rate and accumulated flow is used to predict how the concentration will change as the flow rate through the canister changes. As such, the fuel to air ratio delivered through the injectors can be adjusted in real time to improve drivability and emissions.
14 Citations
13 Claims
-
1. A method determining a canister purge vapor flow condition in an evaporative emissions control system comprising:
-
learning a purge valve mass flow rate; learning a fuel tank mass flow rate; and combining said purge valve mass flow rate with said fuel tank mass flow rate to yield a net mass flow to the canister. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A method of determining a canister mass comprising:
-
determining a fuel tank mass flow rate; determining a purge valve mass flow rate; subtracting said fuel tank mass flow rate from said purge valve mass flow rate to yield a net mass flow rate from said canister; multiplying said net mass flow rate from said canister by a preselected interval of time to yield a value of mass depleted from said canister over said preselected interval of time; and subtracting said value of mass depleted from said canister over said preselected interval of time from a previous canister mass value. - View Dependent Claims (7, 8, 9, 10)
-
-
11. A method of learning a mass of a canister in an evaporative emissions control system comprising:
-
determining a flow condition of said evaporative emissions control system; measuring a vapor concentration value in said evaporative emissions control system; dividing said measured vapor concentration value by a maximum concentration value at said flow condition to yield a concentration conversion fraction; and multiplying a maximum mass of said canister by said concentration conversion fraction. - View Dependent Claims (12, 13)
-
Specification