| 翻訳と辞書 |
| Portable Emissions Measurement System (PEMS) ： ウィキペディア英語版 |
Portable emissions measurement system
A portable emissions measurement system (PEMS) is essentially a lightweight ‘laboratory’ that is used to test and/or assess mobile source emissions (i.e. cars, trucks, buses, construction equipment, generators, trains, cranes, etc.) for the purposes of compliance, regulation, or decision-making. The concept of "in-use" emissions and fuel economy testing was introduced by Leo Breton, an EPA engineer working in the emissions compliance area. Governmental entities like United States Environmental Protection Agency (USEPA), European Union, as well as various states and private sector entities have begun to utilize PEMS in order to reduce both the costs and time involved in making mobile emissions decisions. Various state, federal, and international agencies began referring to this shorthand term in early 2000, and the nickname became part of industry parlance.
==Background==
Since the mid-19th century, dynamometers (or "dyno" for short) have been used to measure torque and rotational speed (measured in rpm) from which power produced by an engine, motor or other rotating prime mover can then be calculated. A chassis dynamometer measures power from the engine through the wheels. The vehicle is parked on rollers which the car then turns and the output is measured. These dynos can be fixed or portable. Because of frictional and mechanical losses in the various drivetrain components, the measured horsepower is generally 15–20 percent less than the brake horsepower measured at the crankshaft or flywheel on an engine dynamometer.〔John Dinkel, "Chassis Dynamometer", ''Road and Track Illustrated Automotive Dictionary,'' (Bentley Publishers, 2000) p. 46.〕 Historically though, dynamometer emission tests are very expensive, and have usually involved removing fleet vehicles from service for a long period of time. Also, the data derived from such testing is not representative of “real world” driving conditions, and cannot be deemed as quantifiable, especially due to the relatively low amount of repeatable tests at such a facility.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Portable emissions measurement system」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|