- Engine test stand
An engine test stand is a facility used to develop, characterize and test engines. The facility, often offered as a product to automotive OEMs, allows engine operation in different operating regimes and offers measurement of several physical variables associated with the engine operation.
A sophisticated engine test stand houses several
sensors (ortransducers ),data acquisition features andactuators to control the engine state. The sensors would measure several physical variables of interest which typically include:
*crankshaft torque
*angular velocity ofcrankshaft
* intake air and fuel consumption rates, often detected using volumetric and/or gravimetric measurement methods
*air-fuel ratio for the intake mixture, often detected using anexhaust gas oxygen sensor
* environment pollutant concentrations in the exhaust gas such ascarbon monoxide , different configurations ofhydrocarbons andnitrogen oxides ,sulfur dioxide , andparticulate matter
*temperatures and gaspressures at several locations on the engine body such asengine oil temperature,spark plug temperature,exhaust gas temperature,intake manifold pressure
* atmospheric conditions such as temperature, pressure,humidity Information gathered through the sensors is often processed and logged through
data acquisition system s. Actuators allow for attaining a desired engine state (often characterized as a unique combination of engine torque and speed). For gasoline engines, the actuators may include an intake throttle actuator, a loading device for the engine such as aninduction motor . The engine test stands are often custom-packaged considering requirements of the OEM customer. They often include a microcontroller based feedback control system with following features:
*closed-loop desired speed operation (useful towards characterization of steady-state or transient engine performance)
* closed-loop desired torque operation (useful towards emulation of in-vehicle, on-road scenarios, thereby enabling an alternate way of characterization of steady-state or transient engine performance)Engine test stand applications
* Research and Development of engines, typically at an OEM laboratory
* Tuning of in-use engines, typically at service centers or for racing applications
* End of production line at an OEM factoryEngine testing for R&D
Research and Development activities on engines at automobile OEMs have necessitated sophisticated engine test stands. Automobile OEMs are usually interested in developing engines that meet the following three-fold objectives:
* to provide highfuel efficiency
* to improve drivability and durability
* to be in compliance to relevant emission legislationConsequently, an R&D engine test stands allow for a full-fledged engine development exercise through measurement, control and record of several relevant engine variables.Typical tests include ones that:
* determine fuel efficiency and drivability: torque-speed performance test under steady-state and transient conditions
* determine durability: aging tests, oil and lubrication tests
* determine compliance to relevant emission legislations: volumetric and mass emission tests over statedemission test cycles
* gain further knowledge about the engine itself: engine mapping exercise or development of multidimensional input-output maps among different engine variables. e.g. a map from intake manifold pressure and engine speed to intake air flow rate.ee also
*
Air flow meter
*Driveshaft
*Dynamometer
*Emission standard
*Emission test cycle
*Engine cart
*Electromagnetic brake Article abouteddy current dynos
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