الموضوع: مجموعة أسئلة بخصوص الثبات

المشاركة الأصلية كتبت بواسطة mohabsaeed

1- القدره على التحكم فى السياره و المناوره بدون فقد السيطره على توجيها , عدم اختلال اتزان و ميلان جسم السياره بشكل كبير فى الملفات السريعه .



2- من بعد سرعه 100 .



3- انظمه التعليق و التوجيه و المكابح فى السياره , تصميم السياره و مدى مقومتها للهواء , نسبه توزيع الوزن مابين المحورين الامامى و الخلفى ., نوعيه و جوده الكاوتش و ابعاده .


4 - عند تأرجح السياره بفعل تيارت الهواء ... او عدم السيطره التامه على توجيه السياره فى المكان المحدد , و عند سوء حاله الطريق بوجود مطبات هوائيه " عالى و واطى " حيث تأثر بشكل سلبى للغايه فى ثبات و اتزان السياره .



5 - من الممكن الحكم على ثبات السياره من مواصفتها و لكن الحكم بالتأكيد لن يكون 100% ... حيث ان التجربه خير دليل , و لكن اذا علمنا ان السياره بها انظمه تعليق متطوره و السياره من شركه ذات سمعه جيده فى صنع السيارات الرياضيه ... فهذا يعطينا حكم مبدئى على ثباتها . , كما ان المواصفات الفنيه " مثل طول قاعده العجلات , عرض السياره , انخفاضها من سطح الارض و تصميمها الايروديناميكى يعطينا فكره مبدأيه عن ثبات السياره و لكن ليس بشكل مؤكد .



6- لا يمكن التأكيد عن ماهى اكثر سياره ثابته " فى العالم " حيث ان لكل قائد سياره فكرته و اسلويه فى قياده السياره ف هناك من يفضل سيارات الدفع الخلفى و هناك من يفضل الدفع الرباعى .... كما ان هناك مدرسه من السائقين يفضلون الدفع الامامى ... و لكل نظام مميزاته و عيوبه .

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موضوع متميز جدا يا أ مُصطفى , الف شكر على طرحك للفكره .

شكرا أ مهاب على ردك الجميل المفصل
أعتقد ان سيارات الجر الامامى أكثر ثباتا من الدفع الخلفى ، وان كانت سيارة زى الفولكس بيتلز(القديمة )ثابتة جدا بردة، بخصوص الدفع الرباعى ...مش عارف...بس فى اراء كتير بتقول انه بيزيد من القدرة على الثبات

شكرا

تسلم يا دكتور على الرسومات الهندسية دى ...مفيدة فعلا
طيب...نظام اتزان المركبة الالكترونى...هو ال ESC
Electronic Stability Control وده اكيد مش موجود فى العربيات الغالية بس ..ولو موجود طبعا هايقولوا عليه

على حسب معلوماتى....انه بيستخدم APS و EPD فى المحافظة على اتزان السيارة ....والا ايه؟

حضرتك جربت قيادة عربية فيها النظام ده؟..وهل شعرت فعلا بفرق كبير فى الثبات؟

شكرا يا دكتور لمتابعتك واهتمامك وكرمك المعلوماتى

عفوا على الحطأ
abs & ebd وليس aps & epd

المشاركة الأصلية كتبت بواسطة مصطفى_صديق

تسلم يا دكتور على الرسومات الهندسية دى ...مفيدة فعلا
طيب...نظام اتزان المركبة الالكترونى...هو ال esc
electronic stability control وده اكيد مش موجود فى العربيات الغالية بس ..ولو موجود طبعا هايقولوا عليه

على حسب معلوماتى....انه بيستخدم aps و epd فى المحافظة على اتزان السيارة ....والا ايه؟

حضرتك جربت قيادة عربية فيها النظام ده؟..وهل شعرت فعلا بفرق كبير فى الثبات؟

شكرا يا دكتور لمتابعتك واهتمامك وكرمك المعلوماتى

esc موجود في ال bmw و المرسيدس وLINCOLEN و PORCHE و .........و على حسب معلوماتي انه فعلا بيستخدم ال aps و ebd في الاتزان بس دا في حالة انك دوست على الفرامل دا غير النظام بتاع فتح العجل الي بيزود الثبات و يا ريت يا دكتور لو في معلومات اكتر انا فعلا عايز اعرف حاجات اكتر عن esc

ودا موضوع كامل عن شرح ال ESC




Electronic Stability Control






When ABS was first introduced back in the mid-1980s, it was strictly a braking system for preventing wheel lockup and skidding. Then traction control was added as the technology evolved to prevent wheel spin during acceleration. Then came an advancement that would take ABS to an entirely new level. Electronic Stability Control (ESC) allows ABS systems to automatically brake individual wheels as needed to improve handling and steering control under all driving conditions.

Electronic stability control essentially makes ABS a full-time expert back seat driver that's constantly monitoring how the vehicle is responding to the driver and road conditions. If a problem starts to develop, it springs into action and takes whatever measures are necessary to get things back under control. This includes reducing engine power by backing off the throttle and/or retarding spark timing, and simultaneously applying one or more brakes to counter the forces that are causing the vehicle to lose control and/or traction. The neat thing is that all this happens automatically without any driver input!

HOW ELECTRONIC STABILITY CONTROL WORKS


To better control vehicle dynamics under all driving conditions, the ABS system needs some additional inputs. This includes a steering angle sensor to monitor the driver�s steering inputs, a yaw sensor to detect changes in vehicle momentum that might cause the vehicle to spin out, oversteer or understeer, and a lateral acceleration (g-force) sensor to monitor changes in deceleration.

When the driver steers the vehicle, the steering angle sensor keeps the ABS control module informed about where the driver is aiming the vehicle and the rate at which the steering wheel is being turned (fast or slow). At the same time, the ABS control module looks at the inputs from its wheel speed sensors to determine if there are any differences in the rotational speeds of the right and left front and rear wheels. Turning a corner causes the inside wheel to rotate at a somewhat slower rate than the outside wheel.

If a vehicle begins to oversteer in a turn and the rear end starts to come around (which would cause the car to spin out), the speed difference between the left and right front wheels increases. If the vehicle understeers (loses front traction and goes wider in a turn), the speed difference between the left and right front wheels decreases.

If the stability control software in the ABS control module detects a difference in the normal rotational speeds between the left and right wheels when turning, it immediately reduces engine power and applies counter braking at individual wheels as needed until steering control and vehicle stability are regained.

Click Here to download/view a video clip of a Chevy Tahoe rollover test. In this clip, which was taken at the Bosch proving grounds in Flat Rock, Michigan, the driver makes a sharp swerve at 35 mph with the stability control system disengaged. The SUV goes up up on two wheels and nearly rolls over. The test is then repeated with stability control engaged and the vehicle remains flat on the ground.

FIRST STABILITY CONTROL APPLICATION

The first vehicles to come factory-equipped with electronic stability control were the 1995 BMW 750iL and 850Ci models with a 5.4 liter V12 engine. The Bosch-built Dynamic Stability Control (DCS) system monitors individual wheel speeds 50 times per second (every 20 milliseconds), and is always active whether the driver is braking or not. If the system senses an understeer or oversteer condition developing, it takes one of two courses of action depending on the amount of cornering force or lateral acceleration that's being developed.

If the vehicle's lateral acceleration is greater than about 0.6g,and the driver brakes normally (not hard enough to bring antilock braking into action), the DSC system modulates brake pressure so that the outside wheels are braked more than the inside wheels. This counteracts the oversteer or yaw effect that might otherwise cause the vehicle to lose control and spin out. If the driver realizes he's going too fast and hits the brakes hard enough to kick in the normal antilock braking, DSC reverts to a normal ABS braking mode allowing the system to selectively modulate rear brake pressure as needed.
MERCEDES ESP STABILITY CONTROL

An even more sophisticated Electronic Stability Program (ESP) appeared in 1996 on V-12 powered Mercedes S600 models. Like BMW system, the Vehicle Dynamics Control (VDC) system is also made by Bosch and provides automatic engine torque reduction and braking if a car enters a corner too fast or makes a sudden steering maneuver. But unlike the BMW system, Mercedes also uses individual front and rear braking to help the vehicle regain control.

With the Mercedes ESP system, the front brakes may be applied separately to help correct the vehicle's attitude. If the car is going into a left turn, for example, and is starting to oversteer, the ESP system applies the right front brake to help bring it back under control. To correct an understeer condition when cornering left, the ESP system applies the left rear brake. A dash warning light also flashes to ..... the driver that the stability control system is active (a glowing triangle with an exclamation mark inside).

The Mercedes system takes inputs from two additional sensors: a lateral acceleration sensor and a yaw velocity sensor. The latter tells the control module if the car is turning on its axis so the computer can compare the input to the steering angle and speeds of the individual wheels.
CADILLAC STABILITRAK

In 1997, Cadillac added Delphi�s new StabiliTrak stability control system to its Seville STS, DeVille Concours and Eldorado ETC models. The StabiliTrak system compares what the driver wants to do with how the car is actually responding. If the car isn�t responding the way the driver wants, or is in danger of spinning or skidding out of control, StabiliTrak slows and stabilizes the car to help the driver regain control.

Like the BMW and Mercedes stability control systems, Cadillac also uses a steering angle sensor, yaw sensor and lateral acceleration (g-force) sensor.
LEXUS VEHICLE STABILITY CONTROL

In 1998, Lexus added the Bosch Vehicle Stability Control (VSC) system to some of its cars. Operationally, it is the same as the Mercedes and Cadillac systems, but adds a brake pressure sensor to monitor driver braking inputs (or lack thereof), and a warning buzzer in addition to the dash light to warn the driver when the system is active.



TOYOTA STABILITY CONTROL

CURRENT STABILITY CONTROL SYSTEMS

Stability control is being integrated into ABS systems on more and more cars, light trucks and SUVs. It makes the most sense on SUVs because of their higher center of gravity and increased risk of roll-over if they get sideways or spin-out on a slick road or suffer a tire blowout.

Vehicle manufacturers currently offer stability control as standard equipment on about 29 percent of all 2006 models, including 57% of all SUVs.

Stability control systems are offered under the following names:

* Acura: Vehicle Stability Assist (VSA)
* Alfa Romeo: Vehicle Dynamic Control (VDC)
* Audi: ESP - Electronic Stabilization Program
* Buick: StabiliTrak
* BMW: Dynamic Stability Control (DSC), including Dynamic Traction Control
* Cadillac: All-Speed Traction Control & StabiliTrak
* Chevrolet: StabiliTrak (except Corvette - Active Handling)
* Chrysler: Electronic Stability Program (ESP)
* Dodge: Electronic Stability Program (ESP)
* DaimlerChrysler: Electronic Stability Program (ESP)
* Fiat: Electronic Stability Program (ESP) and Vehicle Dynamic Control (VDC)
* Ferrari: Controllo Stabilita (CST)
* Ford: AdvanceTrac and Interactive Vehicle Dynamics (IVD)
* GM: StabiliTrak
* Hyundai: Electronic Stability Program
* Honda: Electronic Stability Control (ESC) and Vehicle Stability Assist (VSA) and Electronic Stability Program (ESP)
* Holden: Electronic Stability Program (ESP)
* Infiniti: Vehicle Dynamic Control (VDC)
* Jaguar: Dynamic Stability Control (DSC)
* Jeep: Electronic Stability Program (ESP)
* Kia: Electronic Stability Program (ESP)
* Land Rover: Dynamic Stability Control (DSC)
* Lexus: Vehicle Dynamics Integrated Management (VDIM) with Vehicle Stability Control (VSC) and Traction Control (TRAC) systems
* Lincoln: AdvanceTrak
* Maserati: Maserati Stability Program (MSP)
* Mazda: Dynamic Stability Control
* Mercedes: Electronic Stability Program (ESP)
* Mercury: AdvanceTrak
* MINI Cooper: Dynamic Stability Control
* Mitsubishi: Active Skid and Traction Control MULTIMODE
* Nissan: Vehicle Dynamic Control (VDC)
* Oldsmobile: Precision Control System (PCS)
* Opel: Electronic Stability Program (ESP)
* Peugeot: Electronic Stability Program (ESP)
* Pontiac: StabiliTrak
* Porsche: Porsche Stability Management (PSM)
* Renault: Electronic Stability Program (ESP)
* Rover: Dynamic Stability Control (DSC)
* Saab: Electronic Stability Program
* Saturn: StabiliTrak
* SEAT: Electronic Stability Program (ESP)
* �koda: Electronic Stability Program (ESP)
* Subaru: Vehicle Dynamics Control Systems (VDCS)
* Suzuki: Electronic Stability Program (ESP)
* Toyota: Vehicle Dynamics Integrated Management (VDIM) with Vehicle Stability Control (VSC)
* Vauxhall: Electronic Stability Program (ESP)
* Volvo: Dynamic Stability and Traction Control (DSTC)
* VW: Electronic Stability Program (ESP)


For the NHRSA listings of 2005, 2006 and 2007 model vehicles with stability control, click here.


Stability Control Demonstration

The first video below shows what can happen when a vehicle with a high center of gravity makes a sudden steering maneuver at high speed. The vehicle is traveling at 45 mph on a test track with its stability control system turned off. The second video shows the same test at a slightly faster speed (50 mph) with stability control on. Both videos were taken at a Bosch test track in Farmington Hills MI. The vehicle in these videos was driven by a professional driver, and the SUV was equipped with safety bars to prevent it from rolling over. So DO NOT attempt a roll over test like this yourself!