Leveled fuel levels in a fuel tank disposed at an undercarriage of a construction machine may ensure that the total fuel volume of the fuel tank may be accessible. The fuel tank may include a first fuel compartment and a second fuel compartment fluidly connected to the first fuel compartment and disposed at higher altitudes than the first fuel compartment. Furthermore, the fuel tank may include at least one step integrally formed with the first fuel compartment or second fuel compartment for facilitating entrance to an operator station of the construction machine.

A serviceable draw and return tube assembly for use in fuel tanks is disclosed. The assembly may include a draw tube and a return tube secured to a plate, wherein the plate may be removably secured to a flange, which is fixedly secured to a fuel tank. The process of removably securing the plate to the flange allows for use of different sizes and materials to be utilized in manufacture of the assembly, thereby saving installation time and manufacturing costs.

A filter device, particularly an air breather filter device for venting a fuel tank, includes a housing with a first port provided as an inlet in normal operation of the filter device and a second port provided as an outlet under normal operation of the filter device. The housing encloses at least one filter and an air passage extends from the first port to the second port passing through the filter. Inside the housing a baffle unit is arranged in the housing for covering the at least one first filter in relation to the second port, wherein the baffle unit is arranged to deflect a fluid flow entering the filter device through the second port.

The present invention provides an integrated auxiliary fuel oil tank for a vehicle, which structurally includes a fuel oil tank body, wherein a gear pump assembly and a coarse filter are mounted on the inner side of the fuel oil tank body, and a fuel oil suction passage passing through the coarse filter and a fuel oil return pipeline are arranged between the fuel oil tank body and an engine fuel oil system. The gear pump assembly is provided with a first passage during forward rotation, and a fuel oil filling passage is arranged between the main fuel oil tank of the vehicle and the fuel oil tank body. The gear pump assembly is further provided with a second passage during reverse rotation, and an active fuel oil supply passage is further arranged between the fuel oil tank body and the engine fuel oil system.