Generally speaking, the injection characteristics with heavy, fuel operation is different from that with marine diesel oil in diesel engines, and the fuel viscosity exerts a great influence on the injection characteristics. In order to design the injection system suitably, the influence of the fuel viscosity on the injection characteristics should be understood. In response, a series of experiments and simulation calculations have been carried out. As a result, it is obtained that the decrease of leakage from plunger clearance (up to 50cSt) and the decrease of flow coefficient at nozzle hole (more than 50cSt) exert an influence on the injection characteristics at increasing fuel viscosity. Moreover, it could be said that the optimum viscosity at the inlet of the injection pump is less than 15 - 20cSt in the range of conventional injection system. This paper describes descussions on major factors and these results.
This paper shows the actual circumstances, mentioned below, of cylinder liner wear and piston overhauled data of marine diesel engine, installed the recent low speed and long stroke type. JAPANESE SHIP OWNER'S ASSOCIATION offered the most of these data in addition to MITSUI O.S.K. LINES'. 1. ANALYSIS RESULTS ON THE ENGINE WORKING HOUR BASIS 1. Excessive liner wear are found in early stage within about 10, 000 working hour on “A” and “B” engine type respectively. 2. Generally speaking, ordinary liner wear rate is said to be less than 10/100 mm per 1000 working hour through conventional technical experience. But this analysis data of liner wear rate indicates over 20/100 mm per 1000 working hour on both “A” and “B” engine type excluding “C”. 2. ANALYSIS RESULTS ON THE ENGINE POWER BASIS 1. The cylinder oil feeded rate of “A” “B” and “C” engine type is taken in the recommended value of engine maker concerned, prus more than 0.2-0.4g/ps/h at 30-60% working load of catalog MAX M.C.R. being ordinary using load. 2. However, excessive liner wear on “A” engine type supplied above feeded rate is characteristic of occuring at the point of 50-60% working load of catalog MAX M.C.R.
Relatively small ship hull appendages like distance pieces, side valves, etc., though addressed by Japanese Industrial Standard (JIS) as regards their applicable manufacturing and shop inspection requirements, remain outside the realm of rules and regulations as to other relevant engineering requirements such as the installation method, painting, etc. and thus are left to experience-supported discretion of individual design engineers. Included in this latter category are a number of items other than those specified by JIS, many of them recently developed as, in fact, are side valves built to JIS for that matter. Consequently so broad is a range of products to choose from that the design engineers are frequently at a loss for what rules or standards to turn to in deciding on necessary specifications. Compounding the situation is the existence of the SOLAS '81 rule requirement that recently came into force regarding the prevention of the engine room flooding due to failure of the sea suction and discharge pipes, its interpretation being not necessarily unified among the ship classification societies which serve as inspection agencies for enforcement of the rules. The authors therefore focused their study on formulating design standards for the distance pieces and side valves with emphasis on the installation methods, painting, etc., to serve as a guide for engine department design engineers, especially those at the entry and middle engineering levels.