A hydraulic leak detection system includes a leak detection switch responsive to a level of hydraulic fluid in a tank used by a hydraulic mowing circuit and a lift and lower circuit of a grass mowing machine. The system includes a controller that activates a warning indicator if the leak detection switch indicates the level of hydraulic fluid in the tank is low, but allows the hydraulic mowing circuit and the lift and lower circuit to continue operating until the lift and lower circuit reaches a fully raised position. A solenoid valve may control the level of hydraulic fluid in the tank based on temperature of the hydraulic fluid.

A hydraulic unit includes a hydraulic circuit fluidly connected to a hydraulic actuator, and a control device to control the hydraulic circuit. The hydraulic circuit includes a hydraulic oil tank, a hydraulic pump that supplies the hydraulic oil to the hydraulic actuator from the hydraulic oil tank, a discharge flow path fluidly connecting a discharge side of the hydraulic pump to the hydraulic actuator, a valve that blocks a flow of the hydraulic oil in the discharge flow path, and a pressure sensor that detects a pressure of the hydraulic oil the discharge flow path. In a pressure holding state, when a rotational frequency of the hydraulic pump exceeds a predetermined first determination rotational frequency or when a discharge flow rate of the hydraulic pump exceeds a predetermined first determination discharge flow rate, the control device determines that the hydraulic circuit is abnormal.

An electropneumatic control system for a pneumatic drive and electropneumatic position controller for the system, wherein a volume flow booster having a bypass valve is downstream of the position controller to increase the air capacity, where the pneumatic drive is run in a new operating mode multiple times at maximum air capacity in a first direction to support an operator in adjusting the bypass valve, and where upon exceeding a specified position, the air capacity is set to zero, an overshoot value of the pneumatic drive is determined and output for the operator on a display such that by varying adjustment of the bypass valve, the operator can find and set an adjustment of the valve having low overshoot such that with an adjustment found in such a manner, the transition behavior of the control system can be significantly improved without additional effort.

Fault diagnostics utilize an embedded tracking digital twin of a valve assembly physical part in a microprocessor system of the valve positioner. The digital twin has simulation model parameters including a fault-related simulation model parameter. The digital twin receives a control signal representing a real control of the at least part of the valve assembly, and generates simulated measurements relating to the simulated control result. The digital twin compare the simulated measurements with real measurements that relate to the real control result, to track an error between the results of simulated operation and the real operation of the valve assembly to adjust the fault-related simulation model parameter in a sense that the error is decreased. The fault-related simulation model parameter relates to a specific physical fault in the physical part of the valve assembly, and it is detectable and identifiable based on the simulation model parameter adjusted value.

An actuator system includes a piston-cylinder arrangement including a piston that is movable with respect to a cylinder. A first flow path is in fluid communication with the piston-cylinder arrangement and a second flow path is in fluid communication with the piston-cylinder arrangement. A control system is operable to fluidly connect the first flow path to a source of high-pressure fluid and to connect the second flow path to a drain to move the piston in a first direction. A pressure sensor is fluidly connected to the first flow path and is operable to measure sufficient pressure data during the movement of the piston to generate a pressure versus time curve. The control system is operable to compare the generated pressure versus time curve to a known standard pressure versus time curve stored in the control system to determine the condition of the piston-cylinder arrangement.

A spool valve device includes: a housing with channels; a spool moving to change channel connection statuses; an electric actuator including an electric motor and linear-motion conversion mechanism, the motor rotating an output shaft by torque corresponding to a drive current supplied to the motor, the mechanism converting rotational output shaft movement into straight movement and applying thrust corresponding to the torque to the spool to change position; a biasing member applying biasing force to the spool against the actuator thrust; an angle detector detecting an motor output shaft angular position; a driving portion driving the motor by controlling drive current flow supplied to the motor based on a position command input and the angular position detected by the angle detector; and an abnormality determining portion calculating the spool position based on the detected angular position and determine presence or absence of operation spool abnormality.

A hydraulic circuit for a vehicle driving device includes an oil pump, a clutch oil passage, a cooling oil passage, a pressure regulating valve, and a shift valve. The cooling oil passage guides oil to a cooled portion of a vehicle. Supply of oil to the clutch oil passage and the cooling oil passage is switched by switching of the pressure regulating valve and the shift valve. The cooling oil passage includes: a shaft center cooling oil passage which supplies cooling oil to a shaft center of a rotation shaft of an electric motor mounted on the vehicle; and a cooling oil passage shift valve which switches presence/absence of supply of oil to the shaft center cooling oil passage.

Fueling verification systems and methods for corroboration of vehicle fueling are described herein. The systems and methods provide for verifiable transmission of data collected from a remote source to assure data integrity and maintain proper fuel transmission as part of vehicle fueling. The systems and methods can include collecting a first fuel measure for a fueling process from a delivery source. A second fuel measure can be recorded into a blockchain. The second fuel measure for the fueling process can be received from a recipient source. Then, the first fuel measure and the second fuel measure can be correlated to determine a fueling offset. Then, the delivery source and/or the recipient source can be compensated based on the fueling offset.

A system and method for detecting the functional state of a piloted or direct-operated isolation valve in a hydraulic circuit is presented. In some examples the hydraulic circuit is a steering circuit and the isolation valve provides selective isolation between a hydraulic actuator and one or more metering valves. In some examples, the isolation valve assembly is movable between a first position, in which fluid flow between the metering valve and the actuator is enabled, and a second position, in which fluid flow between the metering valve and the actuator is blocked. When the isolation valve assembly is moved to one of the first and second positions, an inlet port and a pressure sensing port of the isolation valve assembly are placed in fluid communication with each other. When the isolation valve assembly is moved to the other of the first or second position, a second inlet port and the pressure sensing port are placed in fluid communication.

An airflow sensor assembly for an air duct is provided. The airflow sensor assembly includes the air duct having an interior wall and an exterior wall, a high pressure pickup device, a low pressure pickup device, a pressure redirection device, and a pressure sensor. The pressure redirection device is fluidly coupled to the high pressure pickup device and the low pressure pickup device and includes a low inlet, a high inlet, and a common outlet. The pressure sensor is selectively fluidly coupled to the high pressure pickup device and the low pressure pickup device and includes a first inlet and a second inlet. The second inlet is fluidly coupled to the common outlet of the pressure redirection device.