Delphi's Airflow and Gas Injection System (AGIS), enables ultra-accurate metering of gases for validation of automobile emissions testing systems. Vehicle manufacturers have helped reduce automotive emissions with low-emission vehicles (LEVs), ultra-low-emission vehicles (ULEVs), super-ultra-low-emission vehicles (SULEVs), and zero-emission vehicles (ZEVs). Emissions of these vehicles are so low that even the most sophisticated equipment in a laboratory environment cannot accurately measure it.

Delphi's Airflow and Gas Injection System (AGIS) enables accurate metering (constant and variable flow rate) of gases for validation of automobile emissions testing systems. The system is available in a single-gas option (versions 101 and 201) and a multiple-gas option (version 301). In the single-gas constant flow rate mode, the AGIS is an improvement over the existing critical flow orifice (CFO) kits for ultra-low (<1 ppm) concentration of gas injection. This enables validation of emission test equipment (CVS, mini-diluter, SHEDS) at ULEV/SULEV concentration levels.

In the multiple-gas variable flow rate modes, the AGIS recreates the vehicle exhaust by varying concentrations (ppm) of multiple exhaust contaminants (HC, CO, NOX, CO2, N2) and airflow rate as a function of time. The source of the contaminants is compressed gas supply. The HC, CO, and NOx concentrations are controlled using a digital mass flow controller, which has a 1 percent by point accuracy. The COx2 and N2 concentrations are controlled using Delphi's exhaust gas recirculation valves (EGR I and EGR III). The larger diameter EGR valve ensures proper valve operation at high CO2/N2 flow rate without freezing the flow line. The airflow is delivered by a pressure blower, controlled by Delphi's ETC valve, and measured using a Delphi air meter. Closed-loop control of gases and airflow is obtained through a laptop-based controller, which commands the devices and plots the set point and output in real time. Delphi's AGIS version 301 can be used for low-ppm constant flow rate injection or variable flow rate injection to simulate vehicle emissions.


  • Ability to inject fixed concentration for a specified period or varying concentrations as a function of time
  • Real-time, user-friendly, laptop-based control and data acquisition
  • Ability to recreate vehicle exhaust by varying, in real time, airflow and gas flow (up to five gases)
  • Useful for validating emission instruments (sampling system, mini-diluter, and ultrasonic flow meter) in ultra-low ppm range

Potential Applications

 Industry  Description
  • Vehicle emissions simulation
  • Ultra-low-concentration
    propane injection
  •  Precise control of thin film thickness
  • Precision etching of films
  •  Precise control of gas and
    liquid flow


Energy & Environmental Systems: Vehicle Emissions

Patent Number

6,405,745, Ultra accurate gas injection system


Kar; Krishnendu, Semidey; Robert