Technical Specifications

Iowa State University's Off-Highway Vehicle Chassis Dynamometer Laboratory consists of the following pieces of equipment:

Four corner vehicle chassis dynamometer

The four corners of the chassis dyno are loaded by placing a vehicle on the roller bed.   Each roller bed consists of six 500 mm OD steel rollers that are coupled together and powered by an electric motor.  These rollers are 1796 mm long.   Numbering the rollers from the front for the front banks, and from the rear for the rear banks (see in figure below), between the 4th and 5th powered rollers there is a 250 mm OD  lift idler roller (labeled "L" in figure below) that is lower for wheeled vehicles so that the vehicle wheels are cradled between the 4th and 5th powered rollers.  For wheeled vehicles, rollers 1, 2, and 3 are decoupled from the other powered rollers to decrease inertia.  For tracked vehicles, the idler roller is raised and rollers 1, 2, and 3 are coupled creating a bed of seven rollers to support the vehicle track. 

The dyno will support a maximum of 160 kN of axle load or vehicle weight up to 311 kN (70,000 lbs).   Each roller bank can place over to 55,000 N of load on a traction element up to 33 km/h and up to 17,000 N between 33 to 80 km/h depending on the ability to generate tractive force between the tractive element and rollers. Thus the chassis dyno can resist a maximum total horizontal tractive draft force of 222 kN (50,000 lbs).  The dyno supports a wide range of speeds up to 80 km/h.

Overhead view of vehicle chassis dyno

Wheelbase adjustment:  The chassis dyno has an adjustable wheelbase range of 1400 mm so that 2900 to 4300 mm vehicle wheelbases can be accommodated for wheeled vehicle with the wheels cradled between rollers 4 and 5.  Smaller wheelbases down to 1500 mm can be accommodated by placing the wheels between roller 5 and 6.   Tracked vehicle wheelbases are similar, but since the track is not cradled between rollers, there can be more flexibility than wheeled vehicles.   However, wheel base capability can be reduced depending on the track surface length.   

The distance between the inner edge of the rollers or minimum inside tire width is 813 mm (32 in.) and that of the outer roller edges is 4405 mm to support a maximum outside tire width of 4.3 m (172 in.).  A wide range of vehicle tread widths can be accommodated.

Each chassis corner can absorb or motor up to 450 kW (600 Hp), with independent loading of the four corners. The complete AC-Drive system for the chassis dyno and the PTO dyno is limited to 1000 kW.

Power Take-Off (PTO) dynamometer

PTO Dynamometer

The PTO Dynamometer will accommodate both 540 rpm and 1000 rpm PTO speeds and can absorb or motor up to 250 kW (350 Hp) at 1000 rpm and 160 kW (213 Hp) at 540 rpm.

Vehicle Connection Unit (VCU)

The VCU enables the connection of sensors associated with the vehicle to the data acquisition system associated with the dyno control system.  The data acquisition system is based on Beckhoff EtherCat modules, the specifics are listed below:

Vehicle Connection Unit (VCU) associated with the ISU dyno.
The Vehicle Connection Unit (VCU) enables connections to vehicle sensors to the data acquisition capabilities of the dyno control system.

Quantity 12: 0 to 10 V Analog Inputs with BNC connectors (Beckhoff EL3164 EtherCAT Terminal)

Quantity 4: Thermocouple Analog Inputs (Beckhoff EL3314 EtherCAT Terminal)

Quantity 4: 0 to 10 V Analog Outputs with Banana Jack Connectors (Beckhoff EL4104 EtherCAT Terminal)

Quantity 8: Digital Inputs (Beckhoff EL1008 EtherCAT Terminal)

Quantity 8: Digital Relay Outputs (Beckhoff EL2634 EtherCAT Terminal)

Quantity 4: Digital Counter Inputs with BNC connectors (Beckhoff EL1512 EtherCAT Terminal)

Quantity 2: Controller Area Network (CAN) Channels (Beckhoff EL 6751 EtherCAT Terminal)

Data are recorded at 100 samples per second for the entire dyno rig.

VCU Location:  The VCU is located 4.5 m from the lateral center of the dyno and 6.5 m forward from the rear lift rollers (See above figure).  The height of the VCU is 1.5 to 1.8 m above the floor.

Hydraulic Dynamometer

A hydraulic dynamometer is being built to load the vehicle hydraulic systems such as the remote hydraulics of a tractor.  The system can take up to 227 L/min (60 gal/min) at a maximum pressure of 207 bar. 

Fuel Flow Meter

AIC fuel flow meter
ISU Dyno fuel flow meter (Source AIC Systems).


Model Number: AIC-5004 Fuel Flow Master, AIC Systems, measuring 1 to 120 L/hr

Connectors: Quick Disconnect European industrial profile with nominal 1/4 in ID.  See McMaster for plug adapter fittings.

Emissions Measurement Equipment

Bruker OMEGA 5 gas analysis system
The Bruker OMEGA 5 gas analysis system is available for engine gaseous emissions measurement (Source: Bruker).

Bruker OMEGA 5 gas analysis system is available in the lab for the measurement of gaseous emissions from engines including NO/NOX, HC, CO, and CO2. The OMEGA 5 can acquire one scan per second at a spectral resolution of 1 cm-1 with 5 m path length gas cell.  The system includes a heated membrane pump to draw samples from the vehicle exhaust system at up to 10.5 L/min.

Iowa State University gratefully acknowledges Danfoss Power Solutions for their donation to make this facility possible.