冰淇淋賣十年 wrote:
一堆人 還說走走停停 笑死人了 懂不懂車阿
現在車 還有過熱問題 就是系統有問題 現在設計 怎麼操都不會過熱
我上衣台 車特tierra
我還水管掉了 還開了一公里 想說怎麼沒有力了 因為我改手排 發現 系統問題 不知道問題熄火發動 溫度就飆高
因為也沒有水 就趴在地上 水管含一下 裝水 等了15分鐘 又硬開到車廠修理 機油都被我蒸發了
還好沒有燒毀 也只是引擎重新整理一下
有離合器的排檔廂是不一樣的.
經常處於半離合狀態.
離合器會容易磨損.
雖然溫度不見得會真的提高.
但是原廠可能會設計, 判斷這種情形下, 出現警示.
避免過度磨耗.
所以還是善用 S mode 與 Manual Mode.
我只回覆說 走走停停會過熱 看來就真得好笑"
PS乾式變速箱因成本問題，裡面並沒有實體溫度計感應器，那為什麼會有﹝溫度過熱﹞警告？
因為這是工程師寫出來的模擬程式，
程式會計算車主 離合器開合. 轉速. 速度. 環境溫度. 等車況情形，
說白一點就是預防性的保護程式，並不是真的變速箱溫度過高，車主也不用過度擔心！
原文出處 http://articles.sae.org/8287/
The six-speed dual-shift gearbox ("DSG") in Ford's 2011 Fiesta has a four-shaft "gear pack" from Getrag and a dual-clutch assembly from LuK. However, Ford did more than wrap a housing around these components.
Integrating the DSG, which Ford has branded PowerShift, into a new powertrain that can satisfy domestic Ford buyers was a major human-factors engineering effort because the DSG is different, both in componentry and operation.
The DSG has no oil pump, oil cooler, hydraulic controls, or torque converter. Micro-slipping the clutches provides the torsional damping. All shifting is done with electromechanical actuators. Two actuators switch from one clutch to another to instantly effect gear changes with no loss in torque. Others operate forks for gear selection.
DSG's close relationship to a manual transmission means it delivers a fuel economy benefit of about 8 percent vs. a conventional four-speed automatic, Ford claims. U.S. EPA highway fuel efficiency is estimated at 40 mpg for the Fiesta. The transmission is built in a Ford-Getrag joint-venture plant in Mexico. Piero Aversa serves as Ford's PowerShift engineering manager.
According to John Rich, Powertrain Integration Manager during Fiesta development, Ford's objective is a transmission control strategy that warns while gradually trying to guide the driver from low-speed abusive operation into patterns that maintain reasonable clutch assembly temperatures for durability but without annoyance or causing noticeably poor driveability.
This contrasts with the simpler approach of flashing a warning and if the driver doesn't respond appropriately, causing the transmission to shudder while shifting, and at a critical point, throwing the gearbox into neutral.
It might seem most effective to use a temperature sensor to monitor clutch assembly temperatures, but "sometimes sensors have their downsides," Rich explained.
Ford has four primary instrument-panel message center alert levels plus several possible actions the control module may take. These require not only sensor precision throughout the temperature range but for the rated life of the transmission itself. That overall requirement is better served by a virtual sensor—an algorithm that looks at many inputs, including a measurement of electrical energy to each of the two clutch actuators, as well as road speed, engine rpm, ambient temperature, etc.
In fact, there is no transmission temperature sensor, not even in the fluid, as the DSG gear pack contains no clutches and bands. The algorithm was developed in conjunction with LuK with assistance from Getrag, Rich said. Ford started with a simulator program in which "civilian" Ford employees tested a wide range of control strategies.
The simulator provided feel of road grade, including rollback on hills, and the "drivers" faced an instrument panel similar to that on the Fiesta. They were videotaped, including their foot positions, to see how they reacted to different IP messages, so the human factors engineers could see what worked and what some "drivers" tried to resist.
Warning levels
The warning levels start with "Transmission Hot-Stop or Speed Up" plus a warning chime. The message may repeat with a slightly louder chime. If heat buildup continues, the next message is "Transmission Hot-Stop Safely."
If there's no suitable change in driver technique and temperature of the clutch continues to increase, the computer can induce some shift shudder and then display "Transmission Hot-Stop. Wait One Minute" (or subsequently, the same message with more minutes). If the peak temperature level is breached, that message may be accompanied by the DSG going into neutral.
But multiple warnings and then shudder come first. Neutral only occurs when the temperature peak is exceeded, after the multiple warnings. So the declutching is always within a gradual sequence, never abrupt, Rich said. When clutch assembly temperature drops sufficiently, "Transmission Ready" is displayed.
With a properly functioning transmission, excessive heat buildup won't occur during normal or even aggressive driving, Rich claimed. Various forms of abusive low-speed/high-load operation, however, can heat up the DSG clutch. The most severe buildup occurs if the driver uses the gas pedal to hold the car on a relatively steep upgrade, or even creep slightly uphill at perhaps 2-4 mph, Rich said.
The virtual sensor can detect a "hold" and change clutch application torque slightly, so the car will start to roll back (although a warning message precedes that).
The objective is to induce the driver to apply the brakes, which disengages the clutch (producing neutral idle), cooling the clutch.
If the driver attempts to launch repeatedly in a 2-4 mph crawl-along and the clutch assembly is hot, the computer will inhibit launch to allow some cooling. Ford tested its algorithm in Mexico City, Rich said, where drivers tend to keep close to the car in front, and the clutch assembly didn't overheat. The PowerShift does have the creep function that drivers expect, however, along with a hill-hold, in which the brake pressure holds briefly as the driver switches to the gas pedal.
One algorithm that took particularly careful tuning can back off the throttle when the driver has his foot on the brake pedal. A common trait is left-foot braking, with the foot continuously resting on the brake pedal while the right foot is pressing on the gas pedal—a situation for which the clutch assembly temperature algorithm was developed.
However, the control module has to instantly differentiate between that and a motorist trying to stop the car with a stuck throttle. On the Fiesta, a brake pressure transducer in the antilock brake module is monitored, so the computer can distinguish a modest change perhaps because of driver fidgeting from an emergency move.
AEI tested this algorithm during the new Fiesta's U.S. media preview, and we could maintain the throttle with our foot resting even moderately on the brake pedal. But from that point, even a modest but positive press on the pedal brought the engine back to idle.
就以上所提供的文章中. 可以歸類出幾個要點.
乾式PS變速箱. 並沒有實體的溫度計測量變速箱溫度. 而是用虛擬溫度計.
1. 所謂的虛擬溫度計. 是依據 離合器開合. 轉速. 速度. 環境溫度. 來做偵測的.
2. 正常駕駛或激烈駕駛. 是不會累積熱量. 但溫度會升高.
3. 煞車踏板作動的的時間長短. 也就是持續性長短. 也是虛擬溫度計的判斷依據.
4. 爬坡或跑山路. 低轉速高負荷. 容易快速累積熱量.
5. PS 變速箱過熱訊息產生的原因. 是累積的熱量(溫度)所造成. 不是溫度升高而造成.
因為虛擬溫度計. 是由 離合器開合. 轉速. 速度. 環境溫度. 等四個要素來做偵測計算的.
外加煞車踏板制動的持續時間長短. 來換算或計算出變速箱內的溫度.
也就是說持續的產生熱量. 熱量卻無法有效的散發掉.
這應該才是變速箱過熱訊息產生的主因.
網友常說的. 不怕出現問題. 只怕不知問題出現在哪裡?!
若遇到過熱訊息就停路邊等散熱. 不能爬山. 不能走走停停.
以上在台灣的交通環境. FOCUS 是人開人嫌的.
預防勝於治療.
就文章中的問題. 預防解決方式如下. (加快熱量的散發. 減少熱量的產生)
1. 記得隨時開著冷氣 AC 鍵. 強制風扇啟動.(增加空氣流通. 帶走熱量)
2. 蠕行(半離合器)時間要減少. (避免產生熱量)
3. 不要有事沒事就一直踩著(含著)煞車踏板. (因為這也是虛擬溫度計的感測依據)
4. 爬坡或跑山路. 不要維持低轉速高負荷運轉. (文章內有說明. 熱量累積快速)
5. 轉速要依據路況及環境. 而有所變化. (轉速高低就請駕駛者自行領悟了)
以上供參考
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