When the engine speed remains unchanged and the stroke increases, the average speed of the Copeland DJ piston will increase proportionally.
      The average speed of Copeland DJ piston is an important parameter to characterize the degree of engine strengthening.
 
      The problems with the increased average speed of the Copeland DJ piston are:
 
      1. The friction loss increases, and the mechanical efficiency decreases; the thermal load of the piston group increases, and oil with high temperature resistance and high bearing capacity is required;
 
      2. The inertia force increases, and the mechanical vibration and noise become larger;
 
      3. The increase in the flow rate of the intake and exhaust will increase the intake resistance, which will lead to a decrease in the inflation efficiency.
 
      Long-stroke engines are in-line cylinders, generally 4 or 6 cylinders. Copeland DJ piston is characterized by stability, low cost, simple structure, good running balance, small size, high stability, good low-speed torque characteristics, low fuel consumption, compact size and wide application.
 
      The short-stroke engine belongs to the V-shaped cylinder. All the cylinders are divided into two groups, and the adjacent cylinders are arranged together at a certain angle, so that the two groups of cylinders form two planes with an included angle, and the cylinders are V-shaped when viewed from the side. It is characterized by stable operation and space saving. But the structure is more complex, which is not conducive to maintenance and repair, and the cost is high. At the same time, V3, V5, including V10 are not very stable due to their structure or displacement, especially the V103L engine, which is an F1 engine, needs to invest a lot of energy and money to ensure its stability.