TS-112
Electronically Controlled Marine Transmission
Kazuyoshi Harada*, Toshio Imanaka**, Masanori Kondo**, Takashi Miyamoto**
ABSTRACT
This research has established a means by which power is efficiently transmitted to a propeller by introducing electrically controlled techniques into a marine transmission system.
In this research, we have achieved the automatic shift and prevention of engine stall during crash astern (smooth shifting from forward acceleration to backward acceleration), improved sailing acceleration and anchor property, which were impossible to perform using the conventional mechanical controlling system.
Key Words: Electric Technology and Systems, Operation and Propulsion Systems, Automatization and Systematization of Machinery
1. INTRODUCTION
In the marine market, due to recent highly supercharged and high-powered engines, there is a tendency for engine acceleration to deteriorate due to the lack of torque in slow engine speed. Also an engine requires much more time to reach its highest speed while the maximum speed rises.
Such boat equipped with various fishing equipment and sailing devices have increased in number and their operations have become complex. There are demands for labor saving operations and improvement in sailing operability by introducing automatic navigation and fishing.
This thesis introduces an example that improves boat maneuverability by applying electrically controlled techniques to the transmission system as a means of transmitting engine power sufficiently to the propeller.
2. TORQUE TRANSMISSION TO PROPELLER
Generally, the hull equation of motion is as follows:
W・dV/dt = T - R (1)
W: Hull weight
V: Boat speed
T: Driving force
R: Hull resistance
Fig. 1 The hull model of motion
Based on this formula above, the solutions for the two subjects below are introduced using the transmission system:
1] Improvement in acceleration
2] Improvement in deceleration properties by using crash astern
2.1 Improvement in acceleration
Generally, along with accelerated engines, the output of engine torque during slow engine speed has been decreasing. Therefore, if hull resistance is large during starting and accelerating, engines will be overloaded, causing deteriorated acceleration. To ensure the overall boat speed performance, both the maximum boat speed and acceleration must be improved.
To obtain the increased acceleration (dV/dt) of boat speed from formula (1), three following methods are applied:
1] Decrease hull weight W.
2] Lower hull resistance R, and
3] Raise driving force T.
Raising driving force T is an effective means in the transmission system.
* Research & Development Center. Yanmar Diesel Engine Co., Ltd.
5-12-39 Oyodonaka kita-ku, Osaka 531-0076 Japan
FAX: +81-6-6451-1423,
E-mail: kazuyoshi_harada@yanmar.co.jp
** Research & Development Center. Yanmar Diesel Engine Co. Ltd.
