Patent ID: 6561014
Filing Date: 2003-05-13
Classification: F01N,G01M

Abstract:
A method for conducting dynamometric testing of an internal combustion engine at a test site under a simulated atmospheric pressure that differs substantially from an actual ambient atmospheric pressure existing at said test site, said internal combustion engine having an air inlet for supplying an intake airflow for combustion within said internal combustion engine and an exhaust outlet for exhausting an exhaust flow exiting from said internal combustion engine, said method comprising the steps of:A) subjecting said air inlet of said internal combustion engine to said simulated atmospheric pressure; B) subjecting said exhaust outlet of said internal combustion engine to said simulated atmospheric pressure, comprising: connecting an exhaust pump to said exhaust outlet; measuring an exhaust pressure by positioning a pressure sensor at a location substantially adjacent said exhaust outlet; operating said exhaust pump to exhaust said exhaust flow exiting from said internal combustion engine to said test site and to reduce the exhaust pressure measured by said pressure sensor to a pressure at least as low as said simulated atmospheric pressure; operating said exhaust pump to exhaust, from said exhaust outlet, a flow substantially exceeding said exhaust flow exiting from said internal combustion engine while simultaneously; admitting air at said actual ambient atmospheric pressure from said test site to said location substantially adjacent said exhaust outlet, said air admitted from said test site to said location substantially adjacent said exhaust outlet being sufficient to maintain said exhaust pressure substantially equal to said simulated atmospheric pressure, comprising the steps of: providing an exhaust pressure controller; providing a controllable inlet valve for admitting air at said actual ambient atmospheric pressure from said test site to said location substantially adjacent said exhaust outlet, said controllable inlet valve being controlled by said exhaust pressure controller; providing signals from said pressure sensor positioned substantially adjacent said exhaust outlet to said exhaust pressure controller; and controlling said controllable inlet valve with said exhaust pressure controller such that said exhaust pressure is maintained substantially equal to said simulated atmospheric pressure; and C) operating said internal combustion engine while both of said air inlet and said exhaust outlet are subjected to said simulated atmospheric pressure; â€ƒwherein said simulated atmospheric pressure is substantially lower than said actual simulated atmospheric pressure existing at said test site; and â€ƒwherein said exhaust pump has a capacity sufficient to reduce said pressure existing at said exhaust outlet to a pressure at least as low as said simulated atmospheric pressure over substantially an entire range of operating conditions of said internal combustion engine encountered during said step C).