Abstract: The purpose of the present invention is to provide a speed measurement device with which it is possible to accurately identify the highest travel speed of a work machine using the result of measurement by an acceleration sensor. The speed measurement device according to the present invention: detects, from within a record of the travel acceleration of a work machine, a change point at which the work machine transitions from an accelerating state to a steady travel state; and identifies the highest travel speed from a record of the travel speed in a period later than the change point.

Abstract: The purpose of the present invention is to provide a performance diagnostic device capable of diagnosing deterioration in performance of a work machine while taking into account the effects of the amount of load and the characteristics of the site where the work machine operates. A performance diagnostic device according to the present invention uses a reference performance model generated for each combination of the type of operation performed by a work machine, the amount of load, operation details, and site characteristics to diagnose the deterioration in performance of the work machine.

Abstract: An injector diagnosis device 1 includes: an engine sound model generator 14 configured to generate a normal engine sound model and an abnormal engine sound model based on the number of cylinders of the engine and a combustion pattern of the engine; an operating sound obtainment unit 12 configured to obtain the operating sound of the engine operating with the combustion pattern; a frequency characteristics calculation unit 13 configured to calculate the frequency characteristics of the operating sound obtained by the operating sound obtainment unit 12; and an injector diagnosis unit 15 configured to diagnose whether or not the injectors have a failure based on the frequency characteristics of the operating sound which is calculated by the frequency characteristics calculation unit 13, and the normal engine sound model and the abnormal engine sound model which is generated by the engine sound model generator 14.

Abstract: An injector failure diagnostic device 1 diagnoses injector failures for a multi-cylinder internal combustion engine 2 having injectors 21 to 24, each injector injects fuel to the corresponding cylinder. The injector failure diagnostic device 1 includes: an operating sound obtainment unit 12 configured to obtain current operating sound that is operating sound when all of the injectors operate, and obtain pseudo-failure operating sound sequentially for each of the injectors, the pseudo-failure sound being operating sound generated by stopping the fuel injection from one injector while maintaining the operation of the remaining injectors; and a faulty injector identification unit 13 configured to determine whether or not the pseudo-failure operating sound of each injector obtained by the operating sound obtainment unit 12 is similar to the current operating sound to identify a faulty injector.

Abstract: An injector diagnosis device 1 includes: an engine sound model generator 14 configured to generate a normal engine sound model and an abnormal engine sound model based on the number of cylinders of the engine and a combustion pattern of the engine; an operating sound obtainment unit 12 configured to obtain the operating sound of the engine operating with the combustion pattern; a frequency characteristics calculation unit 13 configured to calculate the frequency characteristics of the operating sound obtained by the operating sound obtainment unit 12; and an injector diagnosis unit 15 configured to diagnose whether or not the injectors have a failure based on the frequency characteristics of the operating sound which is calculated by the frequency characteristics calculation unit 13, and the normal engine sound model and the abnormal engine sound model which is generated by the engine sound model generator 14.

Abstract: An injector failure diagnostic device 1 diagnoses injector failures for a multi-cylinder internal combustion engine 2 having injectors 21 to 24, each injector injects fuel to the corresponding cylinder. The injector failure diagnostic device 1 includes: an operating sound obtainment unit 12 configured to obtain current operating sound that is operating sound when all of the injectors operate, and obtain pseudo-failure operating sound sequentially for each of the injectors, the pseudo-failure sound being operating sound generated by stopping the fuel injection from one injector while maintaining the operation of the remaining injectors; and a faulty injector identification unit 13 configured to determine whether or not the pseudo-failure operating sound of each injector obtained by the operating sound obtainment unit 12 is similar to the current operating sound to identify a faulty injector.