自動變速箱的換擋完全由變速箱控制模塊(TCU:Transmission Control Unit)進行控制，其核心邏輯是在最佳的時機進行檔位的切換，以保證車輛的動力性、換擋的平順性和車輛的燃油經濟性。

　　The shifting of automatic transmission is completely controlled by the Transmission Control Unit (TCU), whose core logic is to switch gears at the best time to ensure the vehicle's power performance, smooth shifting, and fuel economy.

　　TCU通過變速箱內部的傳感器、整車控制模塊(PCM：Powertrain Control management)的實時監測數據進行檔位的切換，最主要的是根據車輛速度和油門踏板的深度（即駕駛員對動力的需求）進行及時的檔位切換。

　　TCU switches gears in a timely manner based on the vehicle speed and the depth of the accelerator pedal (i.e. the driver's power demand) through real-time monitoring data from sensors inside the gearbox and the Powertrain Control Management (PCM) module.

　　換擋分為升檔和降檔，升檔存在動力升檔和滑行升檔兩種情況，降檔也存在動力降檔和滑行降檔兩種情況。下面將結合具體的換擋曲線對四種升降檔情況進行講解。

　　Shifting gears can be divided into upshifts and downshifts. Upshifts can occur in two ways: power upshifts and coasting upshifts, while downshifts can also occur in two ways: power downshifts and coasting downshifts. Below, we will explain the four types of upshifts and downshifts based on specific shifting curves.

　　對升降檔進行講解前，我們首先了解一下換擋線shifting schedule/shifting map。

　　Before explaining the upshift and downshift, let's first understand the shifting schedule/shifting map.

　　如下圖所示換擋線是一個由橫坐標為車速(Km/H)縱坐標為油門開度(%)的圖。

　　The shift line shown in the following figure is a graph with the horizontal axis representing the vehicle speed (Km/H) and the vertical axis representing the throttle opening (%).

　　上圖中：實線為升檔換擋點的曲線，虛線為降檔換擋點的曲線。升檔換擋曲線會比降檔換擋曲線的車速更高。

　　In the above figure, the solid line represents the curve of the upshift shifting point, and the dashed line represents the curve of the downshift shifting point. The upshift shift curve will result in a higher vehicle speed than the downshift shift curve.

　　1、動力升檔

　　1. Power upshift

　　正常油門開車過程中，油門開度維持一個相對穩定的值，隨著車速的提高變速箱由一個低檔位升到一個高檔位。

　　During normal throttle driving, the throttle opening maintains a relatively stable value, and as the vehicle speed increases, the gearbox shifts from a low gear to a high gear.

　　如下圖所示:紅色箭頭的換擋過程，油門開度在15%左右，車速由60kph提升到90kph的過程中，車輛在80kph完成咯5檔升6檔的動力升檔過程。

　　As shown in the figure below, during the shifting process indicated by the red arrow, with the throttle opening at around 15% and the vehicle speed increasing from 60kph to 90kph, the vehicle completes the power upshift from 5th to 6th gear at 80kph.

　　2、滑行升檔

　　2. Coasting upshift

　　車輛在下坡過程中，油門開度很小或者無油門情況下，隨著車速的升高，檔位跟隨者升高。這種比較簡單，也很容易理解。還有一種是在超車或者急加速以后出現的滑行升檔。

　　During the downhill process, if the throttle opening is very small or there is no throttle, the gear follower will increase as the vehicle speed increases. This is relatively simple and easy to understand. Another type is coasting upshifting that occurs after overtaking or rapid acceleration.

　　如下圖所示:紅色箭頭的換擋過程，油門開度在80%左右，車速在90kph，松掉油門踏板以后，油門開度從80%向下掉，檔位從綠色實線的左上方4檔完成4檔升5檔。繼續往下走穿過紅色實線，完成5檔升6檔的過程。

　　As shown in the following figure: The shifting process of the red arrow, with the throttle opening at around 80% and the vehicle speed at 90kph, after releasing the throttle pedal, the throttle opening decreases from 80% downwards, and the gear shifts from 4th gear in the upper left corner of the green solid line to 5th gear. Continue walking down and cross the red solid line to complete the process of shifting from 5th gear to 6th gear.

　　3、動力降檔

　　3. Power downshift

　　車輛進行急加速或者超車時為了提供更好的加速性能，變速箱會進行動力降檔。

　　In order to provide better acceleration performance during rapid acceleration or overtaking, the gearbox will downshift its power.

　　如下圖所示:紅色剪頭的換擋過程，車速在90kph，踩油門進行加速。油門開度從18%左右提升到60%左右，箭頭穿越咯紅色虛線，變速箱完成了從6檔到5檔的切換，實現了動力降檔過程。

　　As shown in the figure below: The shifting process of the red scissor is accelerated by stepping on the accelerator at a speed of 90kph. The throttle opening has increased from around 18% to around 60%, and the arrow crosses the red dashed line. The gearbox has completed the transition from 6th gear to 5th gear, achieving the process of power downshifting.

　　4、滑行降檔

　　4. Coasting downshifting

　　滑行降檔是我們最容易理解的換擋形式，每一次開車都會遇到的一種換擋模式。

　　Sliding downshifting is the most easily understood form of shifting, and it is a shifting mode that we encounter every time we drive.

　　如下圖所示:紅色箭頭的換擋，車速從90kph降檔40kph，紅色箭頭穿越咯紅色虛線和綠色虛線，完成咯6檔降5檔和5檔降4檔的兩次滑行降檔。

　　As shown in the following figure: shifting with a red arrow, downshifting from 90kph to 40kph, the red arrow crosses the red and green dashed lines, completing two coasting downshifts from 6th gear to 5th gear and from 5th gear to 4th gear.

　　自動變速箱換擋的4種模式已經全部講解完，除此之外，不同的駕駛模式如經濟、運動、雪地本質上是改變了這套換擋邏輯的“性格”。運動模式會讓升擋更遲、降擋更積極；而經濟模式則相反，一切以省油為先。

　　All four modes of automatic transmission shifting have been explained. In addition, different driving modes such as economy, sport, and snow essentially change the "personality" of this shifting logic. Sports mode will make upshifts later and downshifts more aggressive; The economic model, on the other hand, prioritizes fuel efficiency.

　　簡單來說，自動擋的換擋邏輯就像一個聰明的助手，它根據你的“腳法”和車輛狀態，自動為你選擇最合適的擋位。

　　Simply put, the shifting logic of automatic transmission is like a smart assistant that automatically selects the most suitable gear for you based on your "footwork" and vehicle status.

　　淺見疏漏之處，懇請不吝賜教。

　　I apologize for any omissions and kindly ask for your guidance.

　　本文由 濟南自動變速箱維修  友情奉獻.更多有關的知識請點擊  http://www.ihudie.cn/  真誠的態度.為您提供為全面的服務.更多有關的知識我們將會陸續向大家奉獻.敬請期待.

　　This article is a friendly contribution from Jinan Automatic Transmission Maintenance For more related knowledge, please click http://www.ihudie.cn/ Sincere attitude To provide you with comprehensive services We will gradually contribute more relevant knowledge to everyone Coming soon.