Showing posts with label HONDA ENGINE. Show all posts
Showing posts with label HONDA ENGINE. Show all posts

The steering stability demands of the MotoGP machine




One importance concept of the RC211V, which dominates the Grand-Prix fields with its amazing performance of over 240 horsepower and 330km/h top speed from the feather weight of 145kg, is “rider-friendly & easy-to-control for any rider”. In other words, the principles are such that the machine offers anything that the rider wants while eliminating anything that the rider doesn’t want. In the past, for example, the rider had to hold the machine on the road with all his might fighting relentless kickbacks from the road to prevent loss of tire grip while making a maximum use of the tremendous amount of engine power. Such a story is the history for the RC211V. Despite the enormous power, the output is efficiently transmitted to the road surface. The rider never gets tired, it’s easy to open the throttle, battling on the track doesn’t bother. The machine allows the rider to exhibit his full performance from the start through the final lap. That’s the kind of steering stability that RC211V pursued.

RC211V
Researches of the rotary damper, an optimum design
After the 2003 season, the new hydraulic steering damper has been employed for the RC211V. Concealed in the new-style fairing is the rotary steering damper, instead of a conventional telescopic steering damper. The rotary damper is compact, light in weight, and as the damping system is totally enclosed in the damper housing, it resists against external impacts, less affected by “oil chipping”, without a loss of damping force from warming of the hydraulic fluid. Another advantage of this design is that the system-control parts can be easily mounted around the steering axis. Inherent in the newly-developed rotary steering damper are many features such as the security, function-ability, promise in the future, etc.
2003 RC211V

2002 RC211V
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Feedback to production motorcycles from RC211V
The RC211V, the champion machine of the MotoGP class, which is the pinnacle of the Grand Prix motorcycle racing, brings infinite influences and technical feedback for production motorcycles. The concept “easy to ride for any person” is based on our intent that we want to positively apply the techniques derived from RC211V to production motorcycles because being easy-to-ride and having high performance are ideal features of products for general consumers. Thus, the HESD, which has been developed by further improving the rotary steering damper, is now applied to the production super-sport machine CBR1000RR along with other new features such as the unit pro-link rear suspension, the PGM-DSFI, etc.

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Posted by doudie Tuesday, November 27, 2007 0 comments

HESD (Honda Electronic Steering Damper)



Ensure steering stability by reducing kickbacks at high speeds, while maintaining light-effort handling at low speeds… To satisfy these two contradicting requirements, the development engineers at Honda’s Asaka R&D analyzed in depth the motorcycle handling characteristics and the front end shake triggered by a kickback from the road. The target set at the end of the painstaking researches was the development of an unprecedented steering damper having the damping force variable depending on the running conditions.


Key points of development
During the HESD development, elaborate analyses were exercised especially on the front end shake caused by kickback from the road. Such front end shake is one of the vibration phenomena (vehicle body behavior) during high speed running. Using the large-displacement, super-sport-type model, actual running tests were repeated to set targets for the minimum damping force for light-effort handling and the maximum damping force to reduce front end shake induced by kickback from the road. It has been revealed that the damping characteristics have to be altered depending on the speed and the acceleration to constantly maintain an optimum damping force under various running conditions.
Based on the above-mentioned findings and deriving from the rotary-type steering damper technology applied to the MotoGP machine RC211V, the world’s first, variable damping-type rotary steering damper “HESD”, that alters the flow resistance in the hydraulic damper by an electronic control system depending on the running conditions, has been developed to realize a steering damper having ideal damping characteristics.

HESD
Applied to CBR1000RR
The front end shake when passing on an uneven road surface is the cause of rider discomfort and fatigue. The super-sport motorcycle CBR1000RR, which inherits the DNA of the MotoGP machine RC211V, has been chosen as the first motorcycle to apply the world’s first HESD. With the HESD employed, the CBR1000RR offers to the rider both the sure-footed feeling in high-speed running including the situation on a race track and the light-effort handling at low speeds, thus satisfying rider demands.


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Starting point of VTEC. Revolution responding type valve pausing mechanism "REV"


REV is a system to operate four valves in high speed revolution range in accordance with the revolution of engines and to reduce the number to two valves in low and medium speed revolution range. Pause the operation of valves on both inlet and exhaust sides at the rate of one each per cylinder. A sensor detects the revolution of engines. Four valve operation and two valve operation are automatically changed over, performing the separation and connection of locker-arms by the shift of hydraulic pistons built inside the locker-arms split into two. When four valves are in operation, high power is produced in high speed revolution range while two valves are put into operation, blow-by of fuel air mixture is reduced, so that flow velocity is improved. A high swirl effect and excellent filling efficiency will materialize power improvement in low and medium speed revolution range.

VTEC meeting with various requirements, such as practical use types and low fuel consumption types

VTEC engines started from the REV for motorcycles have undergone subsequently various evolutions. DOHC VTEC engines with switchover for valve timing and the amount of lift for intake and exhaust system aiming at high power and high torque. VTEC engines with a single cam shaft to drive intake valves, switching over low speed valve timing lift and high speed valve timing lift by attaching importance to the balance in the practical use range. Furthermore, VTEC-E engines, which attempted substantial improvement of fuel consumption by enabling lean burn, suspending one valve in low speed range, in addition to the driving by practical valve timing lift in medium and high-speed range. And, 3 STAGE VTEC engines were put out. Switchover was made literally into three stages, using three cams for low, medium and high-speed operations on air inlet side, suspending one valve at low speed operation and taking switchover motion to valve timing lift in medium speed and high-speed operations.
Intelligent new-generation engines, DOHC i-VTEC
Honda has further evolved VTEC and newly developed DOHC i-VTEC, reconciling low fuel consumption of world top class and clean exhaust gas and having high power and rich torque characteristics over the entire ranges. For this engine, highly intelligent valve timing lift mechanism, which combines Honda's original VTEC switching over valve timing and the amount of lift in accordance with the revolution ranges of engines with VTC (variable timing control) continually controlling the phase of air inlet valve timing in accordance with the load on engines.


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From REV to VTEC. Variable Valve Control System ever evolving



It can be said that VTEC, the original Honda variable valve control system originated from REV, revolution responding type valve pausing mechanism, announced in 1983. Receiving the demand for high power for sports bike engines at that time, prior study was started to reconcile high power in high revolution range and excellent drivability and high efficiency from idling throughout all ranges. An epoch-making variable valve system came into being, which enables to switch over from two valves to four valves. This technology later developed into the variable valve timing mechanism, VTEC (variable valve timing and lift electronic control system), which forms the nucleus of automobile engines.


REV born from aiming at reconciliation of 200PS per liter and low revolution range performance
Honda CBR400F equipped with REV, marketed in 1983 Faced with the demand for high power for sports bike engines, a preceding study started off on the assumption of 200PS performance per liter and the development of mass production engines with drivability from the same idling as before. The assignments for the project were to achieve the target power performance and come up with countermeasures against power drop in low speed revolution range and improper idling. It was revealed in the analysis of these issues that the large bore ports for achieving high revolution and high power and for reducing air inlet resistance and the intake and exhaust system with a pleural number of intake and exhaust valves hindered obtaining good idling and low and medium speed revolutions.
An experiment conducted by forcibly stopping several multiple valves made it possible to confirm the stability of idling and a dramatic improvement in the power of low and medium speed revolution range. This was the starting point for the development of valve pausing mechanism (REV: Revolution-modulated valve control), which was applied to the CBR400F in 1983.


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Characteristics of the HFT



A transmission system with a wide range of functions in a single unit, the HFT is a compact and highly efficient infinitely variable transmission system encompassing functions for starting, power transmission and shifting, all on a single shaft. The basic configuration of the system consists of an oil pump for converting engine power into hydraulic pressure, and an oil motor for converting the hydraulic pressure back into power for output. Both are made up of multiple pistons, a distributor valve and a swash plate for piston operation, while the cylinders are integrated into the output shaft, forming the characteristic structure of the HFT.

The HFT also features the world’s first* lockup mechanism for an infinitely variable hydraulic mechanical transmission. When cruising, this lockup mechanism works to minimize transmission efficiency losses, contributing to improved fuel economy.

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Honda Develops HFT, a New Automatic Transmission System for Motorcycles



TOKYO, Japan, October 4, 2007–Honda Motor Co., Ltd. announced that it has developed the Human-Friendly Transmission (HFT), a new automatic transmission system for motorcycles using Honda’s own infinitely variable hydraulic mechanical transmission. Easy to operate, the HFT realizes outstanding relaxed riding comfort, riding feel with direct response and excellent transmission efficiency. The HFT will be installed on the DN-01, a new motorcycle scheduled for market launch to be introduced at the 40th Tokyo Motor Show.


With Honda's own infinitely variable hydraulic mechanical transmission, this HFT realizes the lightweight and compact configuration required for motorcycles. To meet the wide range of rider needs, HFT offers a selection from two fully automatic shifting modes—D mode for ordinary riding and S mode for a sporty riding experience—or the 6-speed manual mode, which gives riders the option of riding with a manual transmission feel. The HFT creates a unique riding feel through easy operation, ranging from relaxed and laid-back riding to nimble and sporty with direct throttle response.

With the aim of providing products useful in the every day lives of customers, Honda has developed and sold motorcycles equipped with easy-to-operate automatic riding technologies. As a pioneer in the era of automatic systems, Honda launched the Super Cub C100 in 1958, equipped with an automatic centrifugal clutch mechanism, which allowed riding without the need of clutch operation. The Eara (750cc), released in 1977, was a first large-sized motorcycle featured a torque converter in Japan. In 1980, Honda put the Tact on the market, a machine equipped with the Honda original continuously variable transmission, the V-Matic, and Honda has continued to develop a variety of new mechanisms up into the present.




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