Patent ID: 7127940
Filing Date: 2006-10-31
Classification: F02D,F02M

Abstract:
1. A method for diagnosing a Liquefied Petroleum Injection fuel pump, comprising the steps of: inputting an engine's Revolutions Per Minute and a fuel pump Pulse Width Modulation signal into an Electronic Control Unit of an interface box; determining whether the inputted engine Revolutions Per Minute indicates that the engine is idling; setting a diagnosis time for diagnosing the fuel pump Pulse Width Modulation signal if the engine Revolutions Per Minute does not indicate that the engine is idling, wherein the diagnosis time is the wait time after which the diagnosis of the fuel pump Pulse Width Modulation occurs and is a duration longer than the time the engine takes to deactivate after a Liquefied Petroleum Gas (LPG) switch is turned off; after the diagnosis time elapses, analyzing the Pulse Width Modulation signal inputted from a fuel pump driver and determining the operation state of the fuel pump; and illuminating a warning lamp if the fuel pump is determined to be operating abnormally or no fuel pump Pulse Width Modulation signal was received.