What it is:
Electrically powered steering uses an electric motor to drive either the power steering hydraulic pump or the steering linkage directly. The power steering function is therefore independent of engine speed, resulting in significant energy savings.
How it works :
Conventional power steering systems use an engine accessory belt to drive the pump, providing pressurized fluid that operates a piston in the power steering gear or actuator to assist the driver.
In electro-hydraulic steering, one electrically powered steering concept uses a high efficiency pump driven by an electric motor. Pump speed is regulated by an electric controller to vary pump pressure and flow, providing steering efforts tailored for different driving situations. The pump can be run at low speed or shut off to provide energy savings during straight ahead driving (which is most of the time in most world markets).
Direct electric steering uses an electric motor attached to the steering rack via a gear mechanism (no pump or fluid). A variety of motor types and gear drives is possible. A microprocessor controls steering dynamics and driver effort. Inputs include vehicle speed and steering, wheel torque, angular position and turning rate.



電子動(dòng)力轉(zhuǎn)向系統(tǒng)的工作原理：
電子動(dòng)力轉(zhuǎn)向系統(tǒng)是通過(guò)一個(gè)電動(dòng)機(jī)來(lái)驅(qū)動(dòng)動(dòng)力方向盤液壓泵或直接驅(qū)動(dòng)轉(zhuǎn)向聯(lián)動(dòng)裝置。電子動(dòng)力轉(zhuǎn)向的功能由于不依賴于發(fā)動(dòng)機(jī)轉(zhuǎn)速，所以能節(jié)省能源。
電子動(dòng)力轉(zhuǎn)向系統(tǒng)的工作方式：
傳統(tǒng)的動(dòng)力方向盤系統(tǒng)使用一條引擎輔助傳送帶駕駛泵浦，提供操作在動(dòng)力方向盤齒輪或動(dòng)作器的一個(gè)活塞協(xié)助驅(qū)動(dòng)的被加壓的流體。
在電動(dòng)液壓的控制，一個(gè)電子動(dòng)力方向盤包括一臺(tái)電動(dòng)機(jī)控制的一個(gè)高效率泵浦。由一個(gè)電控制器調(diào)控泵浦壓力和流速來(lái)控制泵浦的速度，為不同的駕駛路況提供轉(zhuǎn)向。泵浦可以在汽車行駛低速時(shí)打開或者在直線行駛時(shí)關(guān)閉以提供節(jié)能（在當(dāng)代的世界市場(chǎng)上)。
電動(dòng)控制轉(zhuǎn)向使用電動(dòng)機(jī)通過(guò)齒輪齒條機(jī)構(gòu)直接連接以達(dá)到轉(zhuǎn)向控制（無(wú)泵或液體）。多個(gè)電機(jī)驅(qū)動(dòng)器和多驅(qū)動(dòng)控制的實(shí)現(xiàn)是可能的。一個(gè)微處理器控制轉(zhuǎn)向動(dòng)態(tài)和驅(qū)動(dòng)的工作。輸入因子包括車速，轉(zhuǎn)向，車輪扭矩，角度位置和轉(zhuǎn)率。