The diesel engine on the fishing boat is like the “heart” of the fishing boat. which is the power source of the fishing boat to go to sea. and the working condition changes frequently when the fishing boat is operating at sea. The safety requirements for the operation of the main engine are obviously increased. the sea is vast. once the mechanical reasons. resulting in fishing boat accidents. which will seriously threaten the lives of the people on board and the safety of property.
The diesel engine on the fishing boat is like the “heart” of the fishing boat. which is the power source of the fishing boat to go to sea. and the working condition changes frequently when the fishing boat is operating at sea. Safety requirements are obviously increased. the vast sea. once due to mechanical reasons. resulting in fishing boat accidents. which will seriously threaten the lives of the people on board and the safety of property. Therefore. the marine diesel engine should also have the following characteristics.
1. in order to ensure that the fishing boat has sufficient mobility. the propulsion system should be able to reverse operation: large and medium-sized marine main diesel engine is generally invertible diesel engine; small marine diesel engine if not invertible diesel engine. should be correspondingly configured to reverse the car clutch. reverse the car gear box or adjustable pitch propeller. Can directly reverse the main engine. the reverse power should be not less than 75% of the normal rated power. The reversing time should be no more than 15s.
2. the main diesel engine should have a good low-speed working performance. The “specification” stipulates that the minimum stable working speed of the medium-speed engine is generally not higher than 40% of the rated speed. high-speed engine is not higher than 45%.
3. the marine diesel engine should be equipped with a reliable governor and overspeed protection device. Each main engine should be equipped with a reliable governor. so that the main engine speed does not exceed 115% of the rated speed. When the rated power of the main engine is greater than 220kW. it should also be equipped with an overspeed protection device to prevent the speed of the main engine from exceeding 120% of the rated speed. The overspeed protection device should be an independent operating system completely separate from the governor.
The speed control performance of the diesel engine in the diesel generator set should be no more than 10% of the rated speed for instantaneous speed control. no more than 5% of the rated speed for stable speed control. and no more than 5s for stable time (time for speed to return to the fluctuation rate ±1% range). 115%. Parallel operation of the generator set. the governor of the stable rate should be the same as possible.
4. marine diesel engine start should be fast and reliable. The total capacity of the air bottle for the main engine start should be in the case of no supplemental air. for each convertible main engine should be alternately from the cold engine in reverse for not less than 12 consecutive starts; for each non-convertible main engine from the cold engine for not less than 6 consecutive starts. Start the auxiliary engine air bottle capacity. cold engine start power of the largest auxiliary engine not less than 6 times.
The capacity of the battery pack for starting should be in the case of no supplemental charging. from the cold machine start each main engine not less than 12 times; each auxiliary engine not less than 3 times.
5. the requirements of torsional vibration. The main diesel engine propulsion and front-end output power transmission system. important use of rated power equal to or greater than 10kW auxiliary diesel engine system are required to carry out torsional vibration calculation. and review by the ship inspection department.
6、The front end of the main diesel engine of fishing boats needs to drive a variety of auxiliary engines. so it is required to have a large front-end output capacity. the relevant provisions of the marine diesel engine crankshaft strength calculation. crankshaft and other important parts of the material physical and chemical properties. material testing. non-destructive testing. hydraulic testing. etc. have special provisions. for detailed information can call the Hubei JVH consulting.
