Chassis Dynamometer Safety Cummins Southern Plains, Ltd.

Chassis Dynamometer Safety  Setting Up the Truck  Inspection  Running the Truck  Ventilation System  Additional Considerations

Setting up the Truck  Attach the rear safety chain.  The rear tie-down chain is the first restraint to be installed, and the last to be removed.  Do not wrap the rear tie-down chain around brake lines or other items that may be easily damaged.

Setting up the Truck  Rear Safety Chain A keeper to the “boomer” or load tensioner to keep handle from popping off. Orange hook is a safety back up in case tensioner fails.

Setting up the truck (cont.)  The front tie-down straps are the primary restraints that provide safety in the event of a problem.  The rear chain prevents forward movements, but side-to-side movements may occur at the rear of the vehicle.  Before beginning, know your dyno hood clearance distance and that a FE is in the area.

Setting up the Truck  Before placing vehicle on roller, make sure air to the facility is turned on. If no air, truck will roll off roller and may hit wall. Rollers have air applied brakes/spring released.  Picture shows a dent in the back wall from a unit that rolled off.

Inspection  Always inspect the tie-down straps and ratchet mechanisms for wear. Do not use excessively worn or damaged parts. Tie down chains: inspect all bolts and keys. On tie down straps; inspect all strap material and bolts.

Running the Truck  Always remain in the drivers seat when conducting a test.  Never allow observers to be in the room when conducting a test.  Sensors may be connected to fluids under pressure, or may still be hot after a cool-down period. Use extreme caution when disconnecting sensors.  Safety glasses and hearing protection must be worn during a test.

Running the Truck  Never apply the brakes or turn the steering wheel while a test is in progress.  Always set the vehicle parking brakes and the dynamometer roll lock when not executing a test.  Emergency stop button is located on the wall- mounted interconnect box. In the event of an emergency, press the button.  Nobody else should be in area when in operation. Hole in the rear wall from a rock dislodge from a tire during a test run.

Ventilation System  Engine exhaust fumes contain particulate matter, Carbon Dioxide, and Carbon Monoxide..  Never run the engine or conduct a test without the proper room ventilation and evacuation for exhaust fumes.  At least one door of the chassis dyno must be open during operation of the ventilation system.

Ventilation System  These are different exhaust tubes designed for different exhaust systems. The curved one in the right picture is for busses with exhaust out the top. Larger one in front for RVs. Be careful not to place the tubes close to housing as it may bubble the paint on an RV. A variety of hose extensions should be available

Additional Considerations Minimum ladder needed to take opacity measurements on stacks is 8 ft. Housekeeping with the hoses on the swing out rack should be maintained at all times.

Static Electricity  The rotation of rubber tires on steel rolls causes static electricity build-up.  If the rear tie-down chain is wrapped directly around the rear axle or frame cross member, no further grounding should be necessary.  In all other cases it will be necessary to use a grounding clamp attached to the dyno frame or other suitable connection point to earth ground.

Fuel Safety  Keep sparks and open flames away from fuel measurement system and the output of the vent connection.  Personal protective clothing should be worn to prevent diesel fuel contact with the skin or eyes.  Only diesel fuel can be used with the SF-602 fuel measurement system. Other fuels may produce dangerous vapors. The system is NOT explosion proof.  The fuel can vent on the side of the cabinet must be open to a safe place in the atmosphere.  A blocked vent could cause the can to burst or leak.

Calibration  Calibration arm and weight (500 lbs.) for calibrating the sensor on the absorption unit. Need two people for this lift and a cherry picker. Calibration takes place once a year.  Need to open pit to access the mounting point for the torque arm onto the absorption unit. Uses cones and warning line around the pit to keep people out.

Additional Safety Notes  Always remove all test lead and exhaust management devices before removing straps and chains. This will save you from driving off with expensive equipment.  Trip hazards from the test equipment and leads can be a problem in the dyno room. Keep main walkway clear as much as possible.  Oil and coolant spills are common. Housekeeping is essential.