Altitude simulator for dynamometer testing

Abstract

A method and apparatus 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 the test site. The internal combustion engine has an air inlet for supplying an intake airflow for combustion within the internal combustion engine and an exhaust outlet for exhausting an exhaust flow exiting from the internal combustion engine. The method includes the steps of subjecting the air inlet to the simulated atmospheric pressure, subjecting the exhaust outlet to the simulated atmospheric pressure and operating the internal combustion engine while both of the air inlet and the exhaust outlet are subjected to the simulated atmospheric pressure. The apparatus includes an exhaust pressure controller for maintaining the exhaust outlet of the internal combustion engine substantially equal to a determined exhaust pressure during operation of the internal combustion engine and an intake pressure controller for maintaining the air inlet of the internal combustion engine substantially equal to a determined intake pressure during operation of the internal combustion engine.

What is claimed is:  
     
         1 . An apparatus for use in conjunction with performing dynamometric procedures on an internal combustion engine residing in an ambient pressure environment, said engine having an air inlet and an exhaust outlet comprising: 
 a pressure control means coupled to the air inlet and the exhaust outlet for controlling pressure conditions at the air inlet and the exhaust outlet independent of the ambient pressure environment;    said pressure control means effective to isolate the air inlet and exhaust outlet from said ambient pressure environment.    
     
     
         2 . An apparatus for use in conjunction with performing dynamometric procedures on an internal combustion engine residing in an ambient pressure environment, said engine having an air inlet and an exhaust outlet comprising: 
 a first pressure control means coupled to the air inlet for controlling pressure conditions at the air inlet independent of the ambient pressure environment;    a second pressure control means coupled to the exhaust outlet for controlling pressure conditions at the exhaust outlet independent of the ambient pressure environment;    said first and second pressure control means effective to isolate the air inlet and exhaust outlet from said ambient pressure environment.    
     
     
         3 . The apparatus in  claim 2 , wherein the first pressure control means coupled to the inlet comprises an intake pressure controller, a pressure transducer, and a choke valve; wherein the 
 intake pressure controller is operable to control the choke valve based upon input from the pressure transducer.    
     
     
         4 . The apparatus in  claim 2 , wherein the second pressure control means coupled to the exhaust outlet comprises an exhaust pump, a control valve, a pressure sensor and a controller, wherein the controller is operable to control the control valve, based upon input from the pressure sensor.  
     
     
         5 . The apparatus in  claim 4 , wherein the controller is operable to control the exhaust pump.  
     
     
         6 . The apparatus in  claim 4 , wherein the second pressure control means further comprises a flow accumulation device.  
     
     
         7 . The apparatus in  claim 3 , wherein the first pressure control means further comprises a flow accumulation device.  
     
     
         8 . The apparatus in  claim 3 , wherein the first pressure control means further comprises an air conditioning unit for supplying conditioned air flow to the engine.