Diesel hammers are categorized into guide rod type and cylinder type based on their structural design. In the guide rod type diesel hammer, the piston acts as a hammer seat resting on the pile cap, with the cylinder serving as the hammerhead moving along two guide rods. During piling, the pile is first positioned in the pile frame's guide, then the diesel hammer is placed on top of the pile. The cylinder is lifted by lowering the hook, then released to drop into the piston, compressing the enclosed gas in the cylinder. As the cylinder continues to fall, it activates the fuel pump's remote lever on the hammer seat's external press pin elbow joint, spraying oil mist into the main cylinder. The mist ignites upon contact with the high-temperature gas above the ignition point, generating an explosive force that drives the pile downward and pushes the cylinder upward for reheating. When the cylinder falls again along the guide rods, it starts the second impact cycle. The cylinder type diesel hammer uses the cylinder as a hammer seat with an extended cylinder sleeve for guidance, eliminating the need for guide rods. The piston is the hammerhead and can move laterally within the cylinder. During operation, the hammer seat's pile cap is pressed on top of the pile, and the piston is raised with a hook and then dropped to compress the gas in the cylinder, triggering the oil pump, explosion, impact, and ventilation processes.

The operation of a diesel hammer relies on the ignition of compressed diesel fuel, so it's essential to ensure the gas in the cylinder reaches a certain compression ratio. Sometimes, when piling on soft foundations, the recoil force might be too low to ignite the fuel, requiring multiple lifts and drops of the hammerhead with the hook to start. The hammer seat of a diesel hammer includes a diesel fuel injection pump, fuel tank, cooling water tank, and pile cap. The gap between the piston and cylinder sleeve is sealed with an elastic piston ring.

Pile driving machinery uses impact force to drive piles into the ground. It consists of a pile hammer, a pile frame, and auxiliary equipment. The pile hammer is suspended between two vertical guide rods (also known as the dragon gate) on the front side of the pile frame and is lifted with a hoisting hook. The pile frame is a steel structure tower with a winch at the back for lifting piles and pile hammers. The front of the pile frame has two guide rods forming a guiding frame to control the piling direction, ensuring accurate pile penetration as per design. The tower and guiding frame can tilt together for driving inclined piles. The guiding frame can also extend downwards along the tower for piling near riverbanks or ports. The pile frame can rotate and move. The basic technical parameters of a pile driver are the net weight of the impact part, impact energy, and impact frequency. Pile hammers can be classified into drop hammers, steam hammers, diesel hammers, and hydraulic hammers based on their power source.

In a drop hammer pile driver, the pile hammer is a steel weight lifted by a winch and hook, and freely drops along the guiding frame to drive piles. In a steam hammer pile driver, the pile hammer consists of a hammerhead and hammer seat, powered by steam or compressed air, with single-action and double-action steam hammers available. Single-action steam hammers use the piston or cylinder as the hammerhead, with steam lifting the hammerhead and then dropping it along the hammer seat's guide rods. Double-action steam hammers typically use an intensified piston as the hammerhead and the cylinder as the hammer seat, with steam lifting and then driving the hammerhead downward to impact the pile. The rapid reciprocating motion and high frequency create vibrations as the pile penetrates the ground, reducing frictional resistance and enhancing piling effectiveness. The differential double-action steam hammer, with a lighter hammer seat, can relatively increase the effective impact weight, offering stronger performance. The phase shifting of the steam hammers' intake and exhaust valves can be manually controlled or automatically controlled by a cam operated by the hammerhead's side movement, allowing adjustment of the steam hammer's impact stroke.