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Test cycles specify the conditions under which the engine or vehicle is operated during the emission test. There are many different test cycles issued by various national and international governments and working groups. [1] Specified parameters in a test cycle include a range of operating temperature, speed, and load. Ideally these should ...
A representative dynamometer-based emissions test station. For model years prior to 1996, emissions tests were performed using a chassis dynamometer-based test; The vehicle is driven so that the wheels of its main driven axle (front or rear) sit atop the dynamometer rotors, when then are unlocked to rotate freely. A special collections line is ...
The emission is collected at the perpendicular to the emitted light. The emission is also either passed through a filter or a monochromator before being detected by a photomultiplier tube, photodiode, or charge-coupled device detector. The signal can either be processed as digital or analog output.
Emission test results from individual vehicles are in many cases compiled to evaluate the emissions performance of various classes of vehicles, the efficacy of the testing program and of various other emission-related regulations (such as changes to fuel formulations) and to model the effects of auto emissions on public health and the environment.
A blowout (also known as a burst) is a rapid, explosive loss of inflation pressure of a pneumatic tire. The primary cause for a blowout is encountering an object that cuts or tears the structural components of the tire to the point where the structure is incapable of containing the compressed air , with the escaping air adding to further tear ...
A mercury vapor lamp is a line lamp, meaning it emits light near peak wavelengths. By contrast, a xenon arc has a continuous emission spectrum with nearly constant intensity in the range from 300-800 nm and a sufficient irradiance for measurements down to just above 200 nm. Filters and/or monochromators may be used in fluorimeters.
Emission spectrum of a ceramic metal halide lamp. A demonstration of the 589 nm D 2 (left) and 590 nm D 1 (right) emission sodium D lines using a wick with salt water in a flame The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to electrons making a ...
A CATI PEMS being strapped down inside a vehicle. A portable emissions measurement system (PEMS) is a vehicle emissions testing device that is small and light enough to be carried inside or moved with a motor vehicle that is being driven during testing, rather than on the stationary rollers of a dynamometer that only simulates real-world driving.