DOHC Follower Drive Rocker Arm Valve
بِسْمِ اللّهِ الرَّحْمَنِ الرَّحِيْمِ
Salam bikers Nusantara
Tak disangka selama ini bikers Indonesia masih meremehkan sistem DOHC dengan Follower Rocker Arm. Apalgi sudah mulai sindir menyindir alias BC-BCan ala Fansboy.. :D, bukan bermaksud penggiringan opini, hanya sebagai pembukaan wawasan dalam hal teknologi saja. Ada maksud dan tujuan tersebut dibuat dan benang merahnya dimana teknologi ini di aplikasi sebelum dan sesudahnya. Silahkan melihat Kutipan Panjang dibawah ini :
Here is what The Official Press release says:
Cylinder head and cam follower valve drive based on
BMW Formula 1 technology.Overall output, performance characteristics, the quality of the combustion
process and fuel consumption depend largely on the cylinder head and valve drive. In its design and overall configuration, the four-valve cylinder head featured on the S 1000 RR thus offers ideal duct geometry, compact dimensions,
optimum thermodynamics, and an efficient heat balance.The narrow valve angles help to provide ideal intake ducts as well as a compact combustion chamber for high compression and optimum all-round efficiency.
Seeking to achieve maximum power and supreme running smoothness even at very high speeds while at the same time offering a very stiff structure, keeping moving masses to a minimum and optimising the timing overlap on the valves,
the S 1000 RR comes with cam follower control on all moving valve components, with the cylinder head very compact in design, particularly in terms of its height.
Valve play is compensated by means of very small and light adjustment platelets running on the spring plates. On the intake side the spring plates are made of an extra-light aluminium-fibre material.
The moving masses of the cam followers featured on the S 1000 RR are approximately 50 per cent lower than with comparable cup tappets. Such reduction of oscillating masses to an absolute minimum allows fast valve acceleration for a power-oriented cam profile and a high level of free valve cross-sections.
This is also why the cam followers on the S 1000 RR are extremely short and light in their structure and configuration.
A further particular highlight in the design of the cylinder head is the arrangement of the cam follower axes, with both the intake and the exhaust cam followers facing to the rear in the direction of travel. This keeps the cylinder head even more slender as on the usual arrangement with the bearing shafts at
Tight valve angle and light titanium valves.The valve angle is 11.2° on the intake side and 13.3° on the exhaust. The two camshafts made of heat-treated steel and arranged directly above the valves are driven by a toothed chain running on a secondary gear shaft just above the crankshaft. The intermediate gear used in this configuration helps to keep the toothed chain driving the camshafts shorter than would otherwise be the case,
ensuring even greater precision in valve timing and keeping the engine slimmer on the level of the crankshaft.
The intermediate gear transmission also helps to keep the two drive wheels on the crankshafts very short, with the overall layout of the cylinder head remaining very compact.
Optimised valve springs as well as a hydraulic tightening mechanism for minimum friction serve, finally, to minimise both running and drag forces, enhancing the standard of power and performance once again.
Made of extra-light titanium, the intake and exhaust valves are operated by very small and light individual cam followers. The overall geometric layout of the cylinder head allows an ideal transmission ratio on the cam followers of approximately 1:1, reducing flexural forces and bending to an absolute minimum and therefore serving to keep the arms very light and almost filigree in their construction.
Use of such extremely small and light cam followers offers utmost freedom in choosing the optimum valve lift curves and, therefore, the very best power and performance characteristic both for the road and the race track.
Largest valve plate diameter in this segment.The rev limit on the production version of the S 1000 RR is 14,200 rpm, while in purely mechanical terms the engine could run much faster.
Thanks to the large cylinder bore of 80 millimetres or 3.15″, valve plate diameter is larger than on all other engines in this segment, providing the ideal basis for maximum output and performance: Valve plate diameter on the intake side is 33.5 millimetres or 1.32″ and 27.2 millimetres or 1.07″ on the exhaust side, setting a new record in the supersports 1000-cc segment in the interest of a maximum cylinder charge and an optimum charge cycle.
The valve shafts, in turn, measure 5 millimetres or 0.197″ in diameter.
The intake ducts are machined asymmetrically at the transition point leading to the valve seat rings in order to improve the flow of gas and optimise the cylinder charge for even more power at high engine speeds.
The low and flat design of the combustion chamber guarantees a very high level of geometric compression with a thermodynamically optimised cylinder base largely smooth from one side to the other.
With its compression ratio of 13:1, the power unit of the S 1000 RR comes right at the top in terms of production engines, offering an ideal combustion process for optimum yield and maximum efficiency
Kutipan saya qoute dari sumber asli di forum i-bmw (silahkan klik sumber langsungnya), Disini penyempurnaan penggunaan rocker arm yang lebih mengedepankan efisiensi untuk kendaraan sehari-hari maupun performa di sirkuit. Sudut klep in dan klep out lebih sempit dibandingkan CB150R yah. hehehe. tapi overall adopsi ini juga dilakukan oleh BMW. So. adopsi dari teknologi Formula Satu.
Untuk lebih jelasnya silahkan di artikan di atas ya kutipan tersebut atau silahkan baca di forum link I-BMW, Sudah tergambar jelas kelebihan dan penanganan masalah kelemahan roecker arm yang atasi oleh insinyur BMW. Maaf bukan malas menterjemahkan tapi mendorong untuk belajar membaca supaya lebih maju dan bermanfaat membawa positif bagi masyarakat.
Poin dari saya seperti yang disebutkan teknologi dibuat untuk memudahkan bukan untuk diributkan.
Penulis Sekaligus ingin mengucapkan Minal Aidin Walfaidin Mohon Maaf Lahir Batin atas kesalahan maupun kekhilafan baik dari penulisan saya di blog ini maupun di blog teman-teman serekan dalam hal otomotif roda dua.
Semoga Bermanfaat., 🙂
Semangat belajar Gan
Salah satu Cuplikan Video Ketika bergasing di putaran tinggi pada mesin cut half BMW S1000RR, Silahkan di buffer dulu