Abstract: A diagnosis device for an evaporated fuel processing device includes: a pump arranged to pressurize or depressurize a system including the fuel tank and the canister; at least one pressure sensor arranged to sense a pressure within the system; and a fuel temperature sensor arranged to sense a temperature of a fuel within the fuel tank, the diagnosis device being configured to select a first leakage diagnosis using a positive pressure or a negative pressure existing within the fuel tank, or a second leakage diagnosis using a forcible pressurization or a forcible depressurization by the pump, based on a temperature difference between a fuel temperature at a start of driving, and a fuel temperature after an end of the driving, with respect to a request of a leakage diagnosis.

Abstract: An evaporated fuel processing device includes: an evaporated fuel passage connecting a fuel tank and a canister; a purge passage connecting the canister and an intake passage of an internal combustion engine a first purge control valve arranged to open and close the purge passage; a tank open passage connecting a position on an upstream side of the first purge control valve in the purge passage, and the tank; and a second purge control valve arranged to open and close the tank open passage, when the fuel tank becomes a negative pressure, the second purge control valve being opened to introduce an atmospheric pressure through the canister.

Abstract: An evaporated fuel processing device includes: an evaporated fuel passage connecting a fuel tank and a canister; a purge passage connecting the canister and an intake passage of an internal combustion engine a first purge control valve arranged to open and close the purge passage; a tank open passage connecting a position on an upstream side of the first purge control valve in the purge passage, and the tank; and a second purge control valve arranged to open and close the tank open passage, when the fuel tank becomes a negative pressure, the second purge control valve being opened to introduce an atmospheric pressure through the canister.

Abstract: A diagnosis device for an evaporated fuel processing device includes: a pump arranged to pressurize or depressurize a system including the fuel tank and the canister; at least one pressure sensor arranged to sense a pressure within the system; and a fuel temperature sensor arranged to sense a temperature of a fuel within the fuel tank, the diagnosis device being configured to select a first leakage diagnosis using a positive pressure or a negative pressure existing within the fuel tank, or a second leakage diagnosis using a forcible pressurization or a forcible depressurization by the pump, based on a temperature difference between a fuel temperature at a start of driving, and a fuel temperature after an end of the driving, with respect to a request of a leakage diagnosis.

Abstract: A management torque value smaller than a specified torque value is defined beforehand, and a screw ring-form, plug management gauge (11), which is capable of being screwed with plug (3), is prepared. Gauge (11) is provided with marked lines (14a, 14b) showing upper and lower limit positions of tolerance of the orientation of ground electrode (33) when plug (3) and gauge (11) have been screwed with each other. When plug (3) and gauge (11) have been screwed with each other and tightened at the management torque value, suitability of the phase position in the rotational direction is evaluated and managed by whether or not ground electrode (33) of plug (3) is in a range of marked lines (14a, 14b) showing the upper and lower limit positions of the tolerance. With this, it becomes possible to conduct a phase management with consideration of the crushing deformation characteristics of the gasket even with a torque lower than the specified tightening torque.

Abstract: A management torque value smaller than a specified torque value is defined beforehand, and a screw ring-form, plug management gauge (11), which is capable of being screwed with plug (3), is prepared. Gauge (11) is provided with marked lines (14a, 14b) showing upper and lower limit positions of tolerance of the orientation of ground electrode (33) when plug (3) and gauge (11) have been screwed with each other. When plug (3) and gauge (11) have been screwed with each other and tightened at the management torque value, suitability of the phase position in the rotational direction is evaluated and managed by whether or not ground electrode (33) of plug (3) is in a range of marked lines (14a, 14b) showing the upper and lower limit positions of the tolerance. With this, it becomes possible to conduct a phase management with consideration of the crushing deformation characteristics of the gasket even with a torque lower than the specified tightening torque.