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Difference between revisions of "Honda VFR1200F development"
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A great deal of credit for the VFR1200F's compact engine size and prodigious power output must go to the Unicam valvetrain, a Honda-exclusive system that first debuted on the championship-winning [[Honda CRF450R|CRF450R motocross machine]]. A single overhead camshaft directly actuates two intake valves per cylinder while integrating roller rocker arms with screw-type adjusters to actuate two exhaust valves per cylinder. This Unicam technology saves weight and space over a comparable dual-overhead-camshaft design while still maintaining a five-digit redline of 10,200 rpm. As another benefit, this Unicam setup allows for a very flat [[combustion chamber]] for a quicker, more efficient burn. | A great deal of credit for the VFR1200F's compact engine size and prodigious power output must go to the Unicam valvetrain, a Honda-exclusive system that first debuted on the championship-winning [[Honda CRF450R|CRF450R motocross machine]]. A single overhead camshaft directly actuates two intake valves per cylinder while integrating roller rocker arms with screw-type adjusters to actuate two exhaust valves per cylinder. This Unicam technology saves weight and space over a comparable dual-overhead-camshaft design while still maintaining a five-digit redline of 10,200 rpm. As another benefit, this Unicam setup allows for a very flat [[combustion chamber]] for a quicker, more efficient burn. | ||
Another concept carried over from MotoGP design and first offered to the public with Honda's CRF® motocross line is the application of a sealed crankcase system that maintains a mild negative pressure to minimize mechanical pumping or "windage" losses. This system also provides the advantages of a dry sump design (decreased oil churning losses) without the separate oil tank. A scavenging pump pulls oil and gasses out of the crank chamber, and this reduction in atmospheric pressure reduces resistance as the reciprocating engine elements--crankshaft, pistons and [[connecting rod]]s--move. Net result: extra power, enhanced throttle response and improved fuel efficiency. The VFR1200F also incorporates a new, more sophisticated constant oil-pressure monitoring system that has the ability to read a range of variations in oil pressure within a safe operating zone, not just report the presence of minimal oil pressure or no pressure. | Another concept carried over from MotoGP design and first offered to the public with Honda's CRF® motocross line is the application of a sealed crankcase system that maintains a mild negative pressure to minimize mechanical pumping or "windage" losses. This system also provides the advantages of a dry sump design (decreased oil churning losses) without the separate oil tank. A [[scavenging]] pump pulls oil and gasses out of the crank chamber, and this reduction in atmospheric pressure reduces resistance as the reciprocating engine elements--crankshaft, pistons and [[connecting rod]]s--move. Net result: extra power, enhanced throttle response and improved fuel efficiency. The VFR1200F also incorporates a new, more sophisticated constant oil-pressure monitoring system that has the ability to read a range of variations in oil pressure within a safe operating zone, not just report the presence of minimal oil pressure or no pressure. | ||
The new VFR1200F sports another first for Honda among its numerous technical credentials; the use of a Throttle By Wire (TBW) system. With the throttle valve layout in the Programmed Fuel Injection (PGM-FI) system now freed from the restrictions imposed by a mechanically linked/actuated throttle-grip system, the VFR1200F's TBW setup can be made more compact and lighter than conventional cable-operated systems. In addition, this setup incorporates an Electronic Control Unit (ECU) to process information from rider throttle control input, engine speed via a crankshaft position sensor, manifold absolute pressure, gear position, vehicle speed, engine coolant and intake air temperatures, and throttle position help the TBW system to return an even more accurate throttle response in a manner that is more sensitive to rider inputs--large or small--compared to a mechanically linked system, yet with fuel delivery that is smoother and more precise than would be otherwise possible. | The new VFR1200F sports another first for Honda among its numerous technical credentials; the use of a Throttle By Wire (TBW) system. With the throttle valve layout in the Programmed Fuel Injection (PGM-FI) system now freed from the restrictions imposed by a mechanically linked/actuated throttle-grip system, the VFR1200F's TBW setup can be made more compact and lighter than conventional cable-operated systems. In addition, this setup incorporates an Electronic Control Unit (ECU) to process information from rider throttle control input, engine speed via a crankshaft position sensor, manifold absolute pressure, gear position, vehicle speed, engine coolant and intake air temperatures, and throttle position help the TBW system to return an even more accurate throttle response in a manner that is more sensitive to rider inputs--large or small--compared to a mechanically linked system, yet with fuel delivery that is smoother and more precise than would be otherwise possible. | ||