Abstract: A fuel temperature estimation device that can improve the estimation accuracy of a fuel temperature in each part of a fuel channel, is provided. In the invention, the fuel temperature estimation device estimates the fuel temperature of each part of the fuel channel in a vehicle (for example, an injection nozzle, a pressure accumulator, a high-pressure pump), and includes a flow rate measuring device that measures a fuel flow rate of a fuel return system of the fuel channel and a controller. The controller includes a fuel temperature correction unit that corrects an estimated fuel temperature in a fuel injection system based on the fuel flow rate of the fuel return system, and has a function of estimating the fuel temperature using the fuel flow rate of the fuel return system as a parameter.

Abstract: An abnormality diagnosing apparatus configured to diagnose abnormality of a fuel injection amount of a diesel engine includes: an oxidation catalyst provided in an exhaust gas passage; an exhaust gas temperature detector configured to detect an upstream-side exhaust gas temperature and a downstream-side exhaust gas temperature, the upstream-side exhaust gas temperature being an exhaust gas temperature on an upstream side of the oxidation catalyst, the downstream-side exhaust gas temperature being an exhaust gas temperature on a downstream side of the oxidation catalyst; and an abnormality determining unit configured to determine whether the fuel injection amount is excessive or not on the basis of comparison between the upstream-side exhaust gas temperature and the downstream-side exhaust gas temperature.

Abstract: An abnormality diagnosing apparatus configured to diagnose abnormality of a fuel injection amount of a diesel engine includes: an oxidation catalyst provided in an exhaust gas passage; an exhaust gas temperature detector configured to detect an upstream-side exhaust gas temperature and a downstream-side exhaust gas temperature, the upstream-side exhaust gas temperature being an exhaust gas temperature on an upstream side of the oxidation catalyst, the downstream-side exhaust gas temperature being an exhaust gas temperature on a downstream side of the oxidation catalyst; and an abnormality determining unit configured to determine whether the fuel injection amount is excessive or not on the basis of comparison between the upstream-side exhaust gas temperature and the downstream-side exhaust gas temperature.

Abstract: A fuel temperature estimation device that can improve the estimation accuracy of a fuel temperature in each part of a fuel channel, is provided. In the invention, the fuel temperature estimation device estimates the fuel temperature of each part of the fuel channel in a vehicle (for example, an injection nozzle, a pressure accumulator, a high-pressure pump), and includes a flow rate measuring device that measures a fuel flow rate of a fuel return system of the fuel channel and a controller. The controller includes a fuel temperature correction unit that corrects an estimated fuel temperature in a fuel injection system based on the fuel flow rate of the fuel return system, and has a function of estimating the fuel temperature using the fuel flow rate of the fuel return system as a parameter.