arcticflipper Posted December 1, 2005 Share Posted December 1, 2005 Dual CBS for large sports tourers -------------------------------------------------------------------------------- Honda has further advanced Combi Brake, which will work simultaneously on the front and rear wheels by operation of the pedal (left lever) only, to develop dual CBS for application to much larger sports models. Based on the front double disk brake and rear disk brake, this not only brakes the front and rear wheels at the same time by applying the pedal, but also applies braking force on the rear wheel when the right lever is operated. The dual CBS enabled to efficiently decelerate and reduce nosedive. Mechanism of dual CBS In the dual CBS, the hydraulic pressure generated on operation of the right lever will act on the pistons on both ends of "three-pot" calipers on the left and right of the front. The braking force generated then will move the calipers on the left to generate new hydraulic pressure on the secondary master cylinder. The hydraulic pressure will act on the pistons on both ends of three-pot calipers through the proportional control valve, PCV, having the function of pressure reduction, to general braking force on the rear wheel. Furthermore, the hydraulic pressure generated by operation of the pedal will act on the piston in the middle of three-pot calipers in the fore and aft. Similarly to the lever brake, the braking force generated on the front calipers on the left will generate hydraulic pressure in the secondary master cylinder, which will act on the pistons on both ends of the rear calipers. As the result, braking force higher than the time of lever operation will be generated on the rear wheel since all three pistons of the calipers are actuated. Because of these mechanisms, the dual CBS turns out to be CBS also when the lever is operated unlike the case of Combi Brake. In addition to it, distribution characteristics different from the time of operating pedal will be obtained. Braking force distribution characteristics of dual CBS The above figure shows the braking force distribution characteristics of dual CBS. The characteristics of pedal brake lies on the ideal braking force distribution characteristic diagram at the time of maximum loading, similarly to the case of Combi Brake. The characteristics at the time of using the right lever brake, on the other hand, exist on the underside along the ideal braking force distribution characteristics in case of a single rider, which indicates the braking force is distributed rather largely on the front wheel. As the braking force on the front wheel is increased, the braking force on the rear wheel increases at first, then goes down after passing the peak. Such unique distribution characteristics are obtained from the characteristics of PCV exclusively of motorcycles with the function of pressure reduction. When both the pedal and lever are used, the distribution is in the region lying between the two braking force distribution characteristics, depending on the manner of distribution. This will make it easy to obtain a distribution closer to the ideal braking force distribution. ] The above figure compares the deceleration generated by combination of operation of the lever and pedal on completed vehicles between the one equipped with conventional brake and that equipped with dual CBS. The directional axis diagonally to the right (blue) indicates lever input while the directional axis diagonally to the left (red) shows pedal input and the direction along the axis of ordinate (yellow) represents the deceleration generated by combination of respective inputs. The figure on the left shows the deceleration generated by the combined operation of lever and pedal in the conventional brake system. It can be seen that both of the values of input and generated deceleration are low in the single operation by pedal input while high deceleration generated by the combination with lever input takes place in a partly limited input distribution area surrounded by green. The figure on the right shows the deceleration generated by dual CBS. It can be seen that the operation of pedal alone enables to yield high input and high deceleration and that the area in which high deceleration can be generated is expanded. This means that riders can generate high deceleration much more easily. Combined ABS for large sports and tourers ABS directly driven by motor Combined ABS for large sports and tourers are the brake systems combining dual CBS with ABS modulators driven directly by motor, which were developed exclusively for the purpose. The ABS modulators will control hydraulic pressure by directly lifting up and down the position of the piston with a motor. A modulator controls the brake hydraulic pressure of one wheel. The modulators are installed one each on the front and rear wheel. Comparison of characteristics of two types of ABS The above figure compares the control of two types of ABS. The red line at the bottom denotes the changes in brake hydraulic pressure while the black line on top represents motorcycle body speed, and the blue line indicates wheel speed. With the increase in hydraulic pressure, wheels start decelerating by the braking force. However, when wheel speed drops down excessively against motorcycle body speed, that is, wheels are nearing lock conditions, the modulators will lower hydraulic pressure receiving a signal from the ECU. As the wheel speed gets close to motorcycle body speed, the hydraulic pressure will be raised once again. This is repeated time and again in one second. Hydraulic pressure fluctuation is smaller in the ABS directly driven by a motor, so that wheel speed is much smoother and finely controlled. As the result, the pitching of the motorcycle body is reduced. Merits of Combined ABS -------------------------------------------------------------------------------- Advanced brake systems developed by Honda so far, CBS and ABS, were merged as combined ABS to enable to produce a greater effect. The figure below shows a comparison of maximum deceleration generated by operation of the pedal alone in a model between the conventional brake and the advanced brake systems. The deceleration generated by the pedal operation in the conventional brake system is approximately 0.4G (1G = 9.8m/s2). As against to it, the deceleration is increased in CBS by about 1.7 times by obtaining braking force of the front wheel. In case of combined ABS, furthermore, the deceleration is increased as much as approximately 2.3 times. Expansion of Honda's Advanced Brake System A survey was conducted to find out how the advanced brake system of Honda was actually evaluated by users in the market. The following graph shows the satisfaction of users of four models sold in ten countries in Europe equipped with CBS and combined ABS. It can be seen that as many as 87.5% of users have a positive opinion about the advanced brake system. Honda’s advanced brake system has rapidly increased in the latter half of 1990s. The aggregate throughout the world exceeded the mark of 1.5 million units in 2003. Approximately 50% of the models are now equipped with these advanced brake systems in Japan, America and Europe. Future of Advanced Brake System of Honda Honda aims at increasing the application of advanced brake systems to many more models in the future. The required performance and costs vary greatly by categories of motorcycles. Therefore, a proper system must be introduced according to the need. Ceaseless efforts are made for that purpose. For examples, there are systems adapted to the excellent kinetic characteristics of more sporty models and the development of more light and compact ABS. It is required, however, to overcome a variety of tasks for the realization of such goals. Honda will strive for the development and expansion of advanced brake systems from the viewpoint of positively tackling with improving performance. Quote Link to comment Share on other sites More sharing options...
lmmb Posted December 2, 2005 Share Posted December 2, 2005 Thnak you very much. I learn very much! Quote Link to comment Share on other sites More sharing options...
bonox Posted December 6, 2005 Share Posted December 6, 2005 you learn very much!!! I never knew the brake lever was the left one! Quote Link to comment Share on other sites More sharing options...
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