Research on the combustion of alcohol-gasoline blends

Steady state flowbench

Working principle

In order to simulate and optimize engines, it is important to characterize the flow behavior through individual intake and exhaust components. The flow losses through intake and exhaust pipes, runners, ports and valves can be measured using our steady state flow bench. Figure 1 illustrates the working principle of a flow bench. Electric fans are used to obtain a constant over- or underpressure in the settling tank. The pressure difference will force a flow through the measured component, which is a cylinder head in this case. The resulting air mass flow is measured using an accurate mass flow meter and this information can be used to characterize the flow losses.


  • 4 electric fans enable test pressures of over 20 inch water column
  • Bronkhorst EL-FLOW meter enables accurate air mass flow measurements up to 80 Nm3/h
  • Measurement of forward and reverse cylinder valve discharge coefficients as a function of lift
  • Optimization of intake and exhaust geometries for minimal flow losses
  • Measurement of swirl and tumble numbers

Overview of steady state flowbenchSchematic of steady state flowbench working principle

Figure 1: Overview (l.) and schematic (r.) of the steady state flowbench


The flow bench is primarily used for measuring valve discharge coefficients (CD) as a function of valve lift. These are important inputs for gas dynamics simulations in GT-Power. Figure 2 shows measured intake (red) and exhaust (blue) valve discharge coefficients for our CFR test engine.

Intake and exhaust valve CD

Figure 2: Measured intake (red) and exhaust (blue) valve discharge coefficients as a function of valve lift for the CFR test engine.