What are the advantages of nodular cast iron piston?

At present, most diesel engine pistons are made of cast aluminum. Hino Company is an engine company that developed and used ductile iron pistons earlier. Compared with the traditional piston (Figure 4-6), cast iron piston has the following advantages:

(1) cast iron piston has high strength, so it is possible to open a lubricating oil groove at the piston head and spray cooling oil to it through the piston cooling nozzle on the cylinder block, so as to reduce the piston temperature and improve the working environment of the piston.

(2) The position of the first cylinder is lifted upward, so that the gas that cannot participate in combustion is minimized, thereby improving the engine power and reducing emissions.

(3) Due to the high strength of cast iron, the length of the piston can be shortened. Compared with the traditional engine, the engine has longer stroke, fuller expansion of combustion gas, higher output power and better economy.

(4) Because the short cast iron piston is adopted, the height of the whole cylinder block can be reduced, so that the engine structure is more compact.

(5) Because the expansion coefficient of cast iron is smaller than that of aluminum piston, the diameter difference between piston head and piston skirt can be made smaller during manufacturing, so that "cylinder knocking" will not occur during cold start.

Figure 4-6