Marine Diesel Insights

In diesel engines the combustion chamber is where our piston operates and it's where the air is compressed leading to an increase in pressure and temperature. The walls of this combustion chamber are formed by cylinder liners. In the initial designs, these liners were not present in the cylinder block after a while they were introduced as a solution to extend the block's lifespan. Combustion occurs directly within the liner walls rather than in the block itself. Cylinder Block Without Liner(1) Cylinder Block With Liner In the operation of diesel engines one of the tasks performed during major maintenance is the disassembly, measurement, inspection and honing of liners. Prior to the removal of liners the cylinder covers and pistons must be removed. For the removal of liners specialized tools provided by the machine manufacturer need to be used. These tools which are often used for methods like pulling for the removal of tightly fitted components enable us to remove the liner i...

   To investigate the seizure of the crankpin bearing in generator No. 3 of a ship operating we conducted an on-site inspection aboard the ship to identify the root cause. The information provided was as follows: Disassembly and reassembly of covers and pistons are performed for maintenance purposes. After maintenance, the machinery is reassembled. The machine is started and operated for a continuous duration of 15 minutes. Engine connecting rod axial movement is inspected by opening the crankcase covers. An issue of overheating or failure is observed in crankpin bearing No. 1. Figure 1 - From left to right - No. 1 crankpin, No. 1 upper crankpin bearing, No. 1 lower crankpin bearing Firstly, the No. 1 piston connecting rod, which had been removed by the ship's crew, was tightened without the bearing in place. The inner diameter measurement was taken using a micrometer, and it was determined that there was an ovality of nearly 30%. Figure 2 - Example Demonstration of Conn...

One of the rare events for a newly mounted diesel engine has happened. Customer came to us for an unconventional request. They wanted us to change the direction of rotation of two diesel engines. It was quite unusual. I won’t give the detail why they wanted to change it, but I will share how we did it. Engine specifications are 260 mm bore x 385 mm stroke. Rated output of the engines are 2560 kW. Direction of the rotation was clockwise. A new direction of rotation means a lot of part will be replaced. First step was to plan the parts that will be replaced. There are built in pumps that driven by the rotation of crankshaft or camshaft. All those movement transmitted via gears. These gears have helix angle according to the rotation. This means a lot of gear replacement will be occured. Starting of the engines are done by air starting motor. New direction means new air starting motor. Finally a new camshaft needed for opposite direction. We dismantled flywheels and replaced the flywheel g...

  Introduction The general principle in internal combustion engines is to convert the thermal energy generated by the combustion of fuel in a closed chamber into mechanical energy. Although different methods, cycles, fuels, and mechanisms are used the underlying principle of the mechanisms is similar. Diesel engines are commonly used in propulsion systems and power generation systems on ships. Extending the lifespan of diesel engines depends on paying attention to certain criteria during operation and maintenance. In this essay I would like to focus on the importance of cleanliness and highlight key points that I find significant. For further reading I recommend Nigel Calder’s book “Marine Diesel engines: Maintenance, troubleshooting, and repair.” A 4 stroke diesel auxilary engine of a ship [1] We can say that “ cleanliness ” is the primary method for extending the lifespan of diesel engines. In diesel engines we can identify four main elements; air, water , fuel , and oil ....

  Introduction In diesel engines certain bolts are of utmost importance. To ensure that a bolt performs its function effectively it needs to be tightened to a predetermined torque within the elastic range. This torque value is provided by the manufacturer. In some cases tightening the bolt may require multiple steps. For instance in certain bolts after tightening they may need to be loosened and tightened again to achieve the desired tension and proper clamping force. In this article I will share some insight I’ve gained while I was trying to explore the reasons behind the “ tightening, loosening, and re-tightening ” steps provided in the tightening procedures by machine manufacturers. I am quoting a significant portion of the article from a comprehensive study conducted by A. Strozzi [1] and colleagues . In the other sections I have included the sources I used as much as possible. I have also tried to add some insights from my own experiences. Any mistakes made during the proces...

  Introduction The human utilization of circular motion dates back to around 3500 BC. Our journey starting with the wheel encompasses various fields such as transportation, electricity generation, machines, and robots, where we employ circular motion. One way to achieve circular motion is by harnessing the energy contained in fuel. By using the energy obtained from the combustion occurring inside the cylinder we can convert vertical motion sending an object -in our case pistons- up and down into circular motion using various designed shafts. Once we have a rotating object the rest is up to our imagination. Alternators, propellers, gears and more come into play as we transform this circular motion into different forms to serve our needs. Vertical and Circular Motion Today in obtaining this circular motion we have a critical component that has been used for a very long time. Pistons An example of the transition from vertical motion to circular motion can be seen in (1). Pis...