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Systems and methods for evap leak testing

a leak detection and vacuum pump technology, applied in fluid tightness measurement, electrical control, instruments, etc., can solve the problems of increasing limited engine run time, and vacuum pump may be required to perform leak detection, so as to increase the cost of the evap system, reduce efficiencies, and increase energy consumption

Inactive Publication Date: 2017-12-21
FORD GLOBAL TECH LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The patent text describes a method for reducing emissions from a vehicle's evaporative emissions control system during a leak test. The method involves spinning the engine unfueled to pull hydrocarbons away from the system and using the vacuum generated by the spinning engine to push fuel vapors deeper into the system. This reduces the amount of hydrocarbons released into the atmosphere during the leak test. The method can be cost-effective and efficient in reducing emissions.

Problems solved by technology

In some vehicles, such as in plug-in hybrid electric vehicles, engine run time is limited and the vacuum pump may be required to perform leak detection.
However, when evacuating the EVAP system and / or fuel system during a leak test, the vacuum pump may pull hydrocarbons in the canister towards the pump.
However, the inventors herein have recognized issues with such approaches.
In one example, configuring the vacuum pump as a reversible pump may require additional electrical components, such as an H-bridge, which increase the cost of the EVAP system.
Further, reversible pumps may operate at reduced efficiencies when run in reverse, thus leading to increased energy consumption when pushing fuel vapors deeper within the canister.

Method used

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  • Systems and methods for evap leak testing
  • Systems and methods for evap leak testing
  • Systems and methods for evap leak testing

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Embodiment Construction

[0020]This detailed description relates to systems and methods for managing evaporative emissions in a motor vehicle. In particular, this description relates to leak detection tests for an evaporative emissions system of a motor vehicle. The systems and methods may be applied to a hybrid vehicle, such as the hybrid vehicle schematically depicted in FIGS. 1A and 1B. An evaporative emissions control (EVAP) system, such as the example system shown in FIG. 2, may be included in the motor vehicle to regulate evaporative emissions, such as fuel vapor. The evaporative emissions system may include a canister for storing fuel vapors and an evaporative leak check module, comprising a vacuum pump and a valve, enabling leak testing of the fuel system and evaporative emissions system. The evaporative leak check module may be positioned between the canister and the atmosphere. An example method for determining when to run a leak test is described in FIG. 4. The evaporative leak check module may b...

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Abstract

Methods and systems are provided for regulating evaporative emissions from a fuel system. In one example, a method may comprise spinning an engine unfueled responsive to a hydrocarbon concentration at a fresh air end of a fuel vapor canister increasing above a first threshold. The method may comprise spinning the engine to pull hydrocarbons away until a hydrocarbon concentration at a purge end of the fuel vapor canister, opposite the fresh air end, increases above a second threshold.

Description

BACKGROUND AND SUMMARY[0001]Vehicle emission control (EVAP) systems may be configured to store fuel vapors from fuel tank refueling and diurnal engine operations, and then purge the stored vapors during a subsequent engine operation. In an effort to meet stringent federal emissions regulations, emission control systems may need to be intermittently diagnosed for the presence of leaks that could release fuel vapors to the atmosphere.[0002]Evaporative leaks may be identified using a vacuum pump positioned in the emission control system. In some vehicles, such as in plug-in hybrid electric vehicles, engine run time is limited and the vacuum pump may be required to perform leak detection. The vacuum pump may be included in an evaporative leak check module (ELCM) which draws vacuum across a reference orifice to obtain a reference vacuum to which evacuated fuel tank vacuum is compared.[0003]However, when evacuating the EVAP system and / or fuel system during a leak test, the vacuum pump may...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): F02M65/00G01M3/02
CPCG01M3/025F02M65/006F02D41/004F02D41/22F02D2041/225F02M25/0818F02M25/0836F02M25/089Y02T10/40
Inventor DUDAR, AED M.PEARCE, RUSSELL RANDALLYANG, DENNIS SEUNG-MANPETERS, MARK W.
Owner FORD GLOBAL TECH LLC