Do you know what is VTEC ENGINE?

DOCH

The VTEC system is a simple method of endowing the engine with multiple camshaft profiles optimized for low and high RPM operations. Instead of one cam lobe actuating each valve, there are two: one optimized for low-RPM stability & fuel efficiency; the other designed to maximize high-RPM power output. Switching between the two cam lobes is controlled by the ECU which takes account of engine oil pressure, engine temperature, vehicle speed, engine speed and throttle position. Using these inputs, the ECU is programmed to switch from the low lift to the high lift cam lobes when the conditions mean that engine output will be improved. At the switch point a solenoid is actuated which allows oil pressure from a spool valve to operate a locking pin which binds the high RPM cam follower to the low RPM ones. From this point on, the poppet valves opens and closes according to the high-lift profile, which opens the valve further and for a longer time. The switch-over point is variable, between a minimum and maximum point, and is determined by engine load. The switch back from high to low RPM cams is set to occur at a lower engine speed than the up-switch to avoid a situation in which the engine is asked to operate continuously at or around the switch-over point.
Introduced as a DOCH system in the 1989 Honda Integra and Civic CRX SiR (Japan) and 1.6i-VT (Europe) models, which used a 160 bhp (120 kW) variant of the B16A engine. The US market saw the first VTEC system with the introduction of the 1991 Acurra NSX, which used a 3 liter DOHC VTEC V6 with 280 bhp (210 kW). DOHC VTEC engines soon appeared in other vehicles, such as the 1992 Acura Integra GS-R (B17A1 1.7 liter engine). And later in the 1992 Honda Prelude VTEC (H22A 2.2 liter engine with 195 hp) and Honda Del Sol VTEC (B16A 1.6 liter engine). The Integra Type R (1997–2001) available in the Japanese market produces 200 bhp (149 kW; 203 PS) using a B18C5 1.8 liter engine. Honda has also continued to develop other varieties and today offers several varieties of VTEC, such as i-VTEC and i-VTEC Hybrid.

SOCH

As popularity and marketing value of the VTEC system grew, Honda applied the system to (Single Over Head Cam) engines, which share a common camshaft for both intake and exhaust valves. The trade-off was that Honda's SOHC engines only benefitted from the VTEC mechanism on the intake valves. This is because VTEC requires a third center rocker arm and cam lobe (for each intake and exhaust side), and in the SOHC engine, the spark plugs are situated between the two exhaust rocker arms, leaving no room for the VTEC rocker arm. Additionally, the center lobe on the camshaft can only be utilized by either the intake or the exhaust, limiting the VTEC feature to one side.
However, beginning with the J37A4 3.7L SOHC V6 engine introduced on all 2009 Acura TL SH-AWD models, SOHC VTEC was incorporated for use with intake and exhaust valves. The intake and exhaust rocker shafts contain primary and secondary intake and exhaust rocker arms, respectively. The primary rocker arm contains the VTEC switching piston, while the secondary rocker arm contains the return spring. The term "primary" does not refer to which rocker arm forces the valve down during low-RPM engine operation. Rather, it refers to the rocker arm which contains the VTEC switching piston and receives oil from the rocker shaft.The primary exhaust rocker arm contacts a low-profile camshaft lobe during low-RPM engine operation. Once VTEC engagement occurs, the oil pressure flowing from the exhaust rocker shaft into the primary exhaust rocker arm forces the VTEC switching piston into the secondary exhaust rocker arm, thus locking both exhaust rocker arms together. The high-profile camshaft lobe which normally contacts the secondary exhaust rocker arm alone during low-RPM engine operation is able to move both exhaust rocker arms together which are locked as a unit.
The secondary intake rocker arm contacts a low-profile camshaft lobe during low-RPM engine operation. Once VTEC engagement occurs, the oil pressure flowing from the intake rocker shaft into the primary intake rocker arm forces the VTEC switching piston into the secondary intake rocker arm, thus locking both intake rocker arms together. The high-profile camshaft lobe which normally contacts the primary intake rocker alone during low-RPM engine operation is able to move both intake rocker arms together which are locked as a unit.The difficulty of incorporating VTEC for both the intake and exhaust valves in a SOHC engine has been removed on the J37A4 by a novel design of the intake rocker arm. Each exhaust valve on the J37A4 corresponds to one primary and one secondary exhaust rocker arm. Therefore, there are a total of twelve primary exhaust rocker arms and twelve secondary exhaust rocker arms.However, each secondary intake rocker arm is shaped similar to a "Y" which allows it to contact two intake valves at once. One primary intake rocker arm corresponds to each secondary intake rocker arm. As a result of this design, there are only six primary intake rocker arms and six secondary intake rocker arms. 170bhp B16A EQUIPPED CIVIC EG6 SIR

A favourite Honda car of mine is the Eg6, Ek9 Type R and the Dc2 Type R. With a race tuned engine, these machines are exceptionally fast in the touge and circuits.And if you notice, all the car that i mention is in the 90’s where they only bother on producing maximum power without even thinking of fuel consumption and emmission.It is  the glorious day of car modification.
Eventhough all this vtec engine had been around for more tha 20 years, it is still one of the favourite engines to be worked on. Especially the B16 and the B18 series. So i would like to share as much info as possible on the Vtec B Series engine.

Guru Sudah Jadi Kerani (Harian Metro), Apa pendapat Anda?

BESARNYA cabaran dan tanggungjawab dipikul guru masa kini menimbulkan pertikaian di kalangan masyarakat adakah golongan itu mampu melaksanakan amanah dengan sempurna.

FAHAMI MEREKA...ambillah tahu mengenai kesukaran guru supaya mereka rasa dihargai.

PENUH DUGAAN...mengajar pelajar sudah cukup mencabar, guru tidak wajar dibebankan lagi dengan tugasan sampingan remeh sebaliknya fokus pada tanggungjawab hakiki.

Bukan sekadar mendidik, pelbagai tuntutan kerjaya tidak sepatutnya kini mereka galas menjadikan tumpuan terhadap proses penjanaan dan pembelajaran ilmu terjejas.
Lebih menyedihkan, golongan itu turut menjadi sasaran kecaman masyarakat jika gagal melahirkan pelajar cemerlang akademik dan sahsiah diri menyebabkan guru semakin terdesak serta tertekan.

Apakah benar peranan guru sebagai sumber pemangkin ilmu semakin terhakis sebaliknya menjadi golongan itu diperkotak katikkan hingga mereka dalam dilema. Pengerusi Kesatuan Kebangsaan Guru-Guru Lepasan Maktab Semenanjung Malaysia Cawangan Kedah, Anuar Husin, berkata golongan guru hari ini bukan sekadar memegang tanggungjawab sebagai pendidik malah anggota masyarakat secara keseluruhan.

Menurutnya, cabaran utama bukan lagi menyalurkan ilmu kepada pelajar sebaliknya turut mendidik masyarakat melalui peranan di luar waktu persekolahan sekali gus memberi bebanan dalam melaksanakan tumpuan dan tanggungjawab sebenar.

"Dalam perguruan, tugas hakiki adalah mengajar, malangnya guru masa kini dilambakkan dengan pelbagai tanggungjawab sukar dan mencabar. Mereka bukan sekadar guru tapi turut mendidik masyarakat secara keseluruhan.

"Malangnya masyarakat bersikap sambil lewa dan enggan bersama memikul tanggungjawab mendidik menyebabkan mereka semakin tertekan. Guru juga dihimpunkan pelbagai tugasan tidak sepatutnya seperti perkeranian.

"Justeru, bagaimana mahu menumpukan perhatian pada tugasan? Masyarakat hanya tahu memberi tekanan tapi enggan membantu," katanya.

Bukan isu baru guru terpaksa memikul pelbagai tanggungjawab remeh yang menuntut pengorbanan masa, antaranya mengurus dan mengemaskini sistem maklumat pelajar (Emis), sistem salah laku, pendaftaran, yuran, mengurus kumpulan wang amanah pelajar miskin (KWAPM), rancangan makanan dan susu tambahan.

Memburukkan keadaan, mereka terpaksa berhempas pulas menghabiskan sukatan pengajaran kerana dihantar berkursus selain pembelajaran tergendala.

Mengulasnya, Anuar berkata waktu persekolahan padat serta pelbagai perancangan dibuat menjadikan waktu guru semakin terhad hingga menyukarkan proses pembelajaran berjalan lancar.
"Sungguhpun tugasan sampingan tidak sukar, banyak waktu terbuang. Guru sering merungut kerana terlalu terikat dengan pelbagai tuntutan menyebabkan proses pembelajaran tergendala.

"Ia bukan remeh dan perlu diberi perhatian kerana bersangkut paut pencapaian pelajar masa depan. Guru sentiasa dipersalahkan jika pelajar gagal.

"Masyarakat pula mahukan kecemerlangan tapi enggan memahami. Apabila guru gagal menyempurnakannya, bukankah akan menimbulkan konflik? "Tindakan segera perlu diambil kerana bimbang akan menjejaskan mutu pendidikan keseluruhannya," katanya sambil meminta pihak berkenaan mencari penyelesaian terbaik bagi mengatasi kemelut itu.

Ditanya adakah rungutan itu disebabkan guru sudah lama dalam zon selesa, beliau berkata golongan itu boleh menerima perubahan namun perlu ada batasan dan mekanisme tertentu bagi menanganinya.
"Guru boleh menerima perubahan malah sedar tanggungjawab dipikul semakin berat tapi perlu ada tolak ansur. Mereka juga ada tanggungjawab lain perlu dipenuhi seperti keluarga.

"Masyarakat juga harus memberi sokongan dan bersama menggembleng tanggungjawab. Jangan lepaskan sepenuhnya pada guru kerana tidak adil," katanya.

Bagi mengatasi kemelut itu, beliau mencadangkan penyusunan semula tugas pekeranian sedia ada hingga tidak mengganggu tugas hakiki guru selain menambah lagi pembantu guru bertaraf kerani.

Bilangan pelajar turut perlu dikurangkan supaya guru tidak terbeban dalam mengemaskini data peribadi selain menerapkan peranan alumni untuk memberi pembelajaran berbeza berdasarkan pengalaman pekerjaan.

"Konflik perlu diatasi secara berhemah supaya semua pihak mendapat manfaatnya. Penyelesaian bukan sekadar jangka pendek tapi berpanjangan demi kebaikan generasi seterusnya.

"Menjadi guru bukan mudah namun kerjaya itu sangat mulia, perlu berlapang dada menerima apa jua cabaran manakala masyarakat juga jangan bersikap lepas tangan.

"Proses penjanaan ilmu tidak akan terhenti, justeru pelbagai pihak perlu mencari penyelesaian supaya konflik sedia ada dapat diatasi," katanya.

HOW TO CAPTURE GOOD PICTURE? Dreamstime criteria. Look easy but difficult.

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Reasons for refusals

Reasons for refusals

Many of our community members have found it difficult to accurately comprehend the reasons for refusal when they received the rejection notification and wondered what to do in order to comply with the Dreamstime criteria. Given our wish to prevent further disappointment and frustration for our photographers and illustrators due to refusals, here is a brief, but hopefully useful set of specific and often encountered reasons backed by images. These are mostly technical reasons. Along with them, don't forget to keep in mind: - always submit a model release if your image includes people - assign as editorial images that are newsworthy or have stock value but include unremovable logos (i.e. Times Square in New York) - avoid submitting images without stock value. Read various sections of the site and browse its database to see what subjects sell, composition hints, lighting, etc. Remember you are supposed to make photos not just take them! - don't submit images of very common subjects such as flowers or still life, until you made a proper research of the database AND are able to submit better quality than the popular images on the same subject - be very selective, avoid submitting too many similar images; this will help you sell at a higher price, avoiding download dillution; you can submit more similars later, whenever a subject becomes popular.

Distorted pixels - Lens problems

Distorted pixels - Lens fringing

Distorted pixels - Slide scan   I shall first point out a frequent problem that is mostly related to the fast development of the digital market. It is the pixel distortion, generated by a wide set of causes, many of them being of technical nature, such as cheap sensor, cheap lens, poor lighting condisions that demand more that the sensor could give, excessive post-processing, also.

Noise                                                                                                                                                  In order to avoid any misinterpretation of an image as "interpolated", scanning the image at the best optical resolution is the best solution.

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Low light                                                                                                                                             One other major reason is the noise, mostly related to high iso, underexposure, long exposures (especially at high iso, restricted) and over-processing

Overexposed Another problem is underexposure and overexposure, respectively. Fairly easy to correct by finding a medium value of exposure, an average value, in case the camera does not have automatic exposure control (in most cases they do).

Poor lighting                                                                                                                                       While still on the lighting issue, the most common problem when shooting objects and still lifes is the poor light setting.

White Balance

Out of Focus      When doing macro, a powerful light set is necessary in order to be able to shoot at a high speed, as well as a tripod, since one must prevent any camera or subject movement. Any motion blur could lead to an "OUT OF FOCUS" refusal.

Lack of composition A major factor in producing a good image, regardless of media, is the composition. It involves or points out, if not entirely create the message. Composition is also closely related to concept.

Over filtered One of the most important steps in image creation is, of course, the postprocessing. Poor background removal and overfiltering are the most frequent problems that eventually disqualify an image. Proficient knowledge of Photoshop, for example, is not in everyone's reach, and most users tend to make an image look striking on a thumbnail size, but when an editor opens the file at 100% and sees all sorts of distortions, excesses, etc., the image is refused for noise, pixel distortion or overfiltering, although it had, as a raw file, great sales potential.

Poor background removal