Types of dynamometer for your car
Dynamometer is an important engineering device that is basically beneficial for the engines. However, dynamometer can be of different types and one has to make a proper choice when selecting a dynamometer. Dynamometer may be either an engine dynamometer or a chassis dynamometer.
The torque and power is measured directly from the crankshaft of the engine by an engine dynamometer. This is done on removing the engine from the vehicle. These dynamometers are not responsible for the loss of power from the drive train like the transmission, gearbox, differential, etc. the power being delivered to the drive-roller’s surface is measured by a chassis dynamometer. This power is delivered with the help of the drive wheels. The measuring of the output is done when the car is parked on rollers.
The present day chassis dynamometer uses the system of Salvisberg roller. This in comparison to the smooth rollers or the knurled drive rollers has improved the repeatability and traction. There are different types of chassis dynamometers that have eradicated the problem of the possible wheel slippage present in the drive rollers of the past. These rollers are directly attached to the hub of the vehicle and directly measure the torque from the vehicle’s axle. These dynamometers should have a higher reading of about 10-15% in comparison to the “rear wheel” chassis dynamometer.
The chassis dynamometers can be both portable and fixed. The present day dynamometers can perform many functions apart from displaying Horsepower, RPM and Torque. The use of the modern electronics, low inertia, and quick reacting dynamometers it has become possible to get the smoothest run and the best power. Dynamometers like Dynojet helps in adding the diagnostic information of the vehicle to the dyno graph. This can be performed by assembling the data, which is directly obtained from the PCM of the vehicle through OBD communication.
The horsepower that is measured by the rear wheel brake is normally 15-20% less in comparison to the brake horsepower that is measured at the flywheel or crankshaft on an engine dynamometer. This happens due to the mechanical and frictional losses in the different drive train components. Different sources after making a lot of research on various software packages of “engine” dynamometer has concluded that the user of engine dynamometer can make addition of the “frictional loss” channel factors. This “frictional loss” to the flywheel power can be of +10-15% and claims that the power lost is about 20-25% or more.
The facility used for the purpose of characterizing, developing and testing engines is known as the engine test stand. This facility is frequently offered to the automotive OEMs as a product. They allow the operation of engines in various operating organizations. They help measuring the different physical variables that are associated with the operation of the engines.