可變氣門配氣相位和氣門升程電子控制系統(tǒng)VTEC技術(shù)解析

1、可變氣門配氣相位和氣門升程電子控制系統(tǒng)VTEC技術(shù)解析the camshaft and rocker arms, but unlike ordinary engine is the number and control method of cam and rocker arm. Medium and low speed with a small angle of the cam, two valve timing and lift different at low speed, this time a valve lift is very small, almost do not partic

2、ipate in the intake process, the air intake channel basically the equivalent of two valve engine, but due to the flow direction of an intake air barrier gas cylinder center, so it can produce intake eddy current, strong for low speed, especially in the cold car conditions conducive to improving the

3、mixture uniformity, increases the burning rate and decrease the effect of wall surface chilling effect and clearance, making the combustion more fully, thereby improving the economy, and significantly reduce HC and CO emissions; and at high speeds. Through to VTEC solenoid valve to control the hydra

4、ulic oil, so that the two intake rocker arms are connected as a whole and the intake cam from the opening of the longest and largest lift to drive the valve, this time two inlet valve according to the cam profile synchronization. Compared with the low speed operation, greatly increasing the inlet fl

5、ow area and opening duration, so as to improve the power of the engine at high speed. This two kinds of entirely different performance curve of output, Honda engineers so that they are implemented in the same engine, and vividly described as the usual soft driving and wartime intense driving.But VTE

6、C system for gas distribution phase change is still the stage, that is to say the change with gas phase only at a speed jump, but not in a speed range of continuous variable. In order to improve the performance of VTEC system, Honda constantly innovate, introduced the i-VTEC system.Simply put, the i

7、-VTEC system is based on VTEC, added a called VTC (Variable timing control variable timing control device) - a group of inlet valve camshaft timing variable control mechanisms, i.e. i-VTEC=VTEC VTC. At this point, the exhaust valve timing and overlapping time open is variable, controlled by VTC, int

8、o the VTC mechanism so that the engine can have suitable gas distribution phase in large range of speed, which improves the performance of the engine to a large extent.A typical VTC system by the VTC actuator, VTC oil control valve, all kinds of sensors and ECU components. The VTC actuator, VTC oil

9、control valve can generate action according to the ECU signal, the phase of inlet camshaft continuous change. VTC makes the valve overlap time more accurately, ensure the intake valve and exhaust valve, the best lap time, can improve engine power 20%.由本田汽車開發(fā)的VTEC是世界上第一款能同時控制氣門開閉 時間及升程兩種不同情況的氣門控制系統(tǒng)，現(xiàn)

10、在已演變成i-VTECo i-VTEC發(fā)動機與普通發(fā)動機最大的不同是，中低速和高速會用兩組 不同的氣門驅(qū)動凸輪，并可通過電子系統(tǒng)自動轉(zhuǎn)換。此外，發(fā)動機還 可以根據(jù)行駛工況自動改變氣門的開啟時間和提升程度，即改變進(jìn)氣 量和排氣量，從而達(dá)到增大功率、降低油耗的目的。韓國的汽車工業(yè)一向不以技術(shù)先進(jìn)聞名，所以所用技術(shù)也多是借鑒 了德、日等國的經(jīng)驗，而CVVT正是在VVT-i和 i-VTEC的基礎(chǔ)上研 發(fā)而來。以現(xiàn)代汽車的CVVT引擎為例，它能根據(jù)發(fā)動機的實際工 況隨時控制氣門的開閉，使燃料燃燒更充分，從而達(dá)到提升動力、降 低油耗的目的。但是CVVT不會控制氣門的升程，也就是說這種引 擎只是改變了吸、排

11、氣的時間。VTEC發(fā)動機每缸有4氣門（2進(jìn)2排）、凸輪軸和搖臂等，但與普通 發(fā)動機不同的是凸輪與搖臂的數(shù)目及控制方法。中、低轉(zhuǎn)速用小角度 凸輪，在中低轉(zhuǎn)速下兩氣門的配氣相位和升程不同，此時一個氣門升 程很小，幾乎不參與進(jìn)氣過程，進(jìn)氣通道基本上相當(dāng)于兩氣門發(fā)動機， 但是由于進(jìn)氣的流動方向不通過氣缸中心，故能產(chǎn)生較強的進(jìn)氣渦 流，對于低速，尤其是冷車條件下有利于提高混合氣均勻度、增大燃 燒速率、減少壁面激冷效應(yīng)和余隙的影響，使燃燒更加充分，從而提 高了經(jīng)濟性，并大幅降低了 HC、CO的排放；而在高轉(zhuǎn)速時，通過 VTEC電磁閥控制液壓油的走向，使得兩進(jìn)氣搖臂連成一體并由開啟 時間最長、升程最大的進(jìn)氣

12、凸輪來驅(qū)動氣門，此時兩進(jìn)氣門按照大凸輪的輪廓同步進(jìn)行。與低速運行相比，大大增加了進(jìn)氣流通面積和開啟持續(xù)時間，從而提高了發(fā)動機高速時的動力性。這兩種完全不同性 能表現(xiàn)的輸出曲線，本田的工程師使它們在同一個發(fā)動機上實現(xiàn)了， 并且形象地稱之為“平時的柔和駕駛”與“戰(zhàn)時的激烈駕駛”。但是VTEC系統(tǒng)對于配氣相位的改變?nèi)匀皇请A段性的，也就是說其改 變配氣相位只是在某一轉(zhuǎn)速下的跳躍，而不是在一段轉(zhuǎn)速范圍內(nèi)連續(xù) 可變。為了改善VTEC系統(tǒng)的性能，本田不斷進(jìn)行創(chuàng)新，推出了 i-VTEC 系統(tǒng)。簡單地說，i-VTEC系統(tǒng)是在VTEC系統(tǒng)的基礎(chǔ)上，增加了一個稱為 VTC（Variable timing control4可變正時控制”）的裝置 一組進(jìn)氣門 凸輪軸正時可變控制機構(gòu)，即i-VTEC=VTEC+VTC。此時，排氣閥 門的正時與開啟