نيسان تطرح إبداع جديد في تكنولوجيا تحكم الصمامات المتغيرة
نظام ( VVEL )
Variable Valve Event & Lift (VVEL)
أحداثيات الرفع للصمامات المتغيرة
لقد ترجمت لكم قدر المستطاع من الإنجليزي إلى العربية وخلاصة الترجمة تجدونها في الفقرة التالية
نظام ((VVEL الجديد بالتزامن مع (C-VTC) سيتحكمان بمراحل وأحداثيات الرفع للصمامات المتغيرة.
وسينتج عن ذلك أداء أفضل من ناحية القوة للمحرك وسيؤدي ألى إنخفاض في التلوث بمقدار 10% , وهذا النظام
يتحكم في مداخل الهواء عند مدخل الصمامات وعلى الفور يدخل ألى غرف الإحتراق مما سيؤدي إلى
زيادة في الفاعلية وسهولة في تدفق الهواء إلى الإسطوانات أكثر من السابق .
الخلاصة: نيسان ستقدم نظام متطور للإقتصاد في الوقود وزيادة في القوة وإنخفاض في التلوث بمقدار 10%
من بداية عام 2008 وأول سيارة ستزود بهذا النظام الجديد هي سيارتها الجديدة من إنفنتي G37 الكوبيه
القادمة إلينا أواخر 2007 ومن ثم سيعمم على جميع سيارات إنفنتي ونيسان .
هذا النظام مشابه لنظام (VVTI) لدى تويوتا ولكنه يتفوق عليه في الأداء
Nissan Introduces Innovative Valve Control Technology [Mar. 29, 07]
- Variable Valve Event & Lift (VVEL) delivers significant improvements in dynamic and environmental performance -
TOKYO (March 29, 2007)--Nissan Motor Co., Ltd. today introduced a new engine technology that delivers a balance
of responsiveness and power, fuel efficiency and low emissions. The new system combines the technologies behind
Nissan’s newly developed Variable Valve Event and Lift (VVEL)*1 and continuous valve timing control (C-VTC) to
deliver significantly enhanced performance. This advanced technology will be available to customers worldwide through
the Nissan and Infiniti product lines.
Nissan announced plans to install the VVEL system, which contributes up to a 10%*2 reduction in carbon-dioxide
emissions, on its products worldwide starting from FY07 under the Nissan Green Program 2010. The first product to
feature the VVEL technology is the Infiniti G37 coupe, scheduled to be unveiled at the upcoming New York International
Auto Show in April, 2007.
While conventional engines control air intake using a throttle valve, VVEL-equipped engines do this directly at the intake
valves, continuously controlling their valve events and lifts. C-VTC and VVEL together control the valve phases and its
valve events and lifts, allowing free-control of the valve timing and lift. This results in more efficient airflow through the
cylinder and significantly improves responsiveness, optimizing the balance between power and environmental performance.
The new engine offers the following advantages depending on driving range:
Higher fuel efficiency
At low-to-mid load ranges, the system controls air intake at the intake-valve, immediately before it enters the combustion
chamber, in contrast with conventional engine air intake via a throttle valve, leading to increased efficiency by easing
airflow through the cylinder.
In the low- and medium-rpm ranges*3, intake-valve lift is kept low to reduce camshaft friction and improve fuel efficiency.
Better response
Controlling air intake at the intake-valves improves acceleration response by allowing more dense air into the cylinders from
the start of acceleration.
More power
In the low-rpm range, the intake-valves open for a shorter period, preventing blowback of the air-fuel mixture and improving torque.
l In the high range, greater intake-valve lift allows increased air intake to deliver greater torque outputs.
Cleaner emissions
Intake-valve timing is optimized on startup, when the engine is still cool, to quickly raise the temperature of exhaust
gases and more quickly activate the catalytic converter.
Hydrocarbon emissions are reduced in the low-to-medium range by keeping intake-valve lift low, speeding intake flow
and dispersing the fuel into a fine mist, resulting in more efficient full combustion.
The VVEL improves fuel efficiency most effectively in the low-to-medium operating range, thus it is best matched to
the multiple-cylinder and higher displacement engines, that typically operate within that range.
Under the Nissan Green Program 2010, Nissan has announced plans to develop gasoline-powered engines with CO2 emissions
reduced to levels comparable with diesel engines, to be available globally by 2010. For multiple-cylinder, high-displacement
engines, Nissan will combine VVEL technology with the direct-injection system.
The VVEL system
A rocker arm and two types of links close the intake-valves by transferring the rotational movement of a drive shaft
with an eccentric cam to the output cam. The movement of the output cam can be varied by rotating the control
shaft within the DC motor and changing the fulcrums of the links. This makes a continuous adjustment of the valve lift amount possible.
*1 VVEL: Variable Valve Event & Lift
*2 This percentage improvement is measured by Nissan by comparing an engine with the VVEL system to an identical engine without it.
*3 The accelerator pedal is pressed halfway or less.
* From Nissan News.
نيسان تطرح إبداع جديد في تكنولوجيا تحكم الصمامات المتغيرة
العرض العادي
