The piston in direct contact with the
high temperature gas instantaneous temperature can reach 2500K above, therefore,
is serious, and the radiation condition is very poor, so the piston when the
temperature is high, top up to 600 ~ 700K, and the temperature distribution is
not uniform; piston the top under air pressure, especially the power stroke
gasoline engine maximum pressure, up to 3 ~ 5MPa, the diesel engine is up to 6 ~
9MPa, which makes the piston impact, and bear the side pressure; the piston in
the cylinder at a high speed (8 ~ 12m/s) reciprocating motion, and speed changes
constantly, it produces a large inertial force, the piston is great additional
load. The piston to work in such harsh conditions, will produce deformation and
accelerated wear, will produce additional load and thermal stress, at the same
time by the chemical action of gas.…