Homojen Dolgulu Sıkıştırma İle Ateşlemeli Bir Benzin Motoru İçin Kam Tasarımı Ve İmalatı

Abstract

ÖZETBu çalışmada, homojen dolgulu sıkıştırma ile ateşlemeli (HCCI) bir benzin motoru için kam tasarımı ve imalatı yapılmıştır. 38 mm temel daire çapı ve 124° supap açık kalma süresi için, HCCI yanma karakteristiğine uygun 3,5, 5,5 ve 7,5 mm düşük supap kalkma miktarına sahip kamlar tasarlanmıştır. Dairesel yay eğrisi kullanılarak kam profillerinin genel geometrik modelleri elde edilmiş ve elde edilen kam profili modelleri fourier serisi ile ekstrapole edilerek daire yay eğrisine karşılık gelen eşitlikler türetilmiştir. Tasarlanan kam profilleri için iticinin hız, ivme ve sıçrama etkileri araştırılmıştır. Elde edilen sonuçlar 5. dereceden klasik spline yöntemi ile elde edilen kamlar ile mukayese edilmiştir. Klasik spline fonksiyonları ile elde edilen kam profillerinde supap kalkma miktarı arttıkça kamın iticiye tek noktadan temas özelliğinin kaybolduğu, iticilerin ivme ve sıçrama değerlerinin çok fazla arttığı görülmüştür. Geometrik modeli elde edilen kam profillerinin fourier serileri ile ekstrapole edilmesiyle, yüksek supap kalkma miktarlarında bile kamın iticiye tek noktadan temas etme özelliğinin kaybolmadığı, düşük hız ve ivme ile çalışması sonucu sürtünme ve atalet kuvvetlerinin azaldığı görülmüştür.Anahtar kelimeler: HCCI yanma, kam tasarımı, üç dairesel yay eğrisi, fourier serisi, spline metodu CAM DESIGN AND MANUFACTURING FOR A HOMOGENEOUS CHARGE COMPRESSION IGNITION GASOLINE ENGINE ABSTRACTIn this study, cams were designed and manufactured for a homogenous charge compression ignition (HCCI) gasoline engine. Low lift cams were designed accordance with HCCI combustion characteristics for 38 mm base circular diameter, 124° dwell angle, 3.5, 5.5 and 7.5 mm valve lifts. Generic geometric models of cam profiles were obtained using circular arc curves. Obtained models were fitted with fourier series and circular arc curve was derived from the corresponding equations. Speed, acceleration and jerk effects of the follower were investigated for designed cam profiles. Obtained results were compared with cams obtained by 5 th degree classical spline method. It has been shown that feature a single point of contact of cam into the follower has been lost and acceleration and jerk values of the follower increased so much as long as valve lift increase in the cam profiles obtained by classical spline functions. It has been shown that feature a single point of contact of cam into the follower has not been lost by fitting fourier series of obtained geometric model of cam profile even high valve lifts. Friction and inertia forces decreased due to the low speed and acceleration operation.

Linear generator design for concentrating solar power technologies: Optimization and prototype development

“…The Stirling engine is an ECE that offers numerous advantages over internal combustion engines (ICEs) and other types of heating engines. These advantages include [49‐52] Stirling engines have the highest thermal efficiency. Emissions (NOx, CO, and hydrocarbon) are low when using fossil fuels due to external combustion. Vibration and noise are less when compared with ICEs. They require little maintenance and have a long life as they do not have components such as camshaft, valves, oil filter and pump, air filter, when compared with ICE. …”

“…Stirling engines have some disadvantages including [49, 50–52] Low acceleration due to thermal lag. The technology is new and still evolving. Greater mass when compared with ICEs. Difficulty of reliable insulation between practice and crank spaces. …”

Dimensionless design approach to translating flat faced follower mechanism with two-circular-arc cam

“…A negative maximum acceleration occurs at the point-C. The maximum velocity and the negative maximum acceleration of the follower can be calculated with the following equations (Arabaci et al, 2014;Grohe and Russ, 2010).…”

“…In addition to the design of circular arc cams, the production is easy and economical (Lanni et al, 1999). Circular arc cams design uses two or three circular arcs (Grohe and Russ, 2010). Although there are cam designs using four and more circular arcs, it is not preferred because of the complexity in the mathematical model (Grohe and Russ, 2010;Xiaoyi, 1999).…”

“…Circular arc cams design uses two or three circular arcs (Grohe and Russ, 2010). Although there are cam designs using four and more circular arcs, it is not preferred because of the complexity in the mathematical model (Grohe and Russ, 2010;Xiaoyi, 1999). Circular arc cams can be used with flat-faced or roller follower mechanisms.…”