| 翻訳と辞書 |
| variable compression ratio ： ウィキペディア英語版 |
variable compression ratio
Variable compression ratio is a technology to adjust the compression ratio of an internal combustion engine while the engine is in operation. This is done to increase fuel efficiency while under varying loads. Higher loads require lower ratios to be more efficient and vice versa. Variable compression engines allow for the volume above the piston at 'Top dead centre' to be changed. For automotive use this needs to be done dynamically in response to the load and driving demands.
== Advantages ==
Petrol engines have a limit on the maximum pressure during the compression stroke, after which the fuel/air mixture detonates rather than burns. To achieve higher power outputs at the same speed, more fuel must be burned and therefore more air is needed. To achieve this, turbochargers or superchargers are used to increase the inlet pressure. This would result in detonation of the fuel/air mixture unless the compression ratio was decreased, i.e. the volume above the piston made greater. This can be done to greater or lesser extent with massive increases in power being possible. The down side of this is that under light loading, the engine can lack power and torque. The solution is to be able to vary the inlet pressure and adjust the compression ratio to suit. This gives the best of both worlds, a small efficient engine that behaves exactly like a modern family car engine but turns into a highly tuned one on demand.
Variable Compression Ratio (VCR) is becoming increasingly desirable as oil prices increase and car buyers have an increased interest in fuel economy. In addition to this, Global Climate Warming requires measures from international community. To Automobile industry it means stricter limits to car emissions, especially CO2. Variable compression ratio is one cost effective way achieving these targets. In addition VCR allows free use of different fuels besides petrol e.g. LPG or ethanol.
The cylinder head can be altered by using a hydraulic system which is connected to the crank shaft and responds according to the load and acceleration required..
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「variable compression ratio」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.
|
|