A system and method for controlling a hydraulic fracturing pumping system is described herein. The method can include stopping an engine coupled to a hydraulic fracturing pumping system including at least one pump by supplying pressure from an accumulator to a hydraulic braking system including a brake. The method can also include starting the engine coupled to the hydraulic fracturing pumping system and releasing the brake.

A system and method for controlling a hydraulic fracturing pumping system is described herein. The method can include stopping an engine coupled to a hydraulic fracturing pumping system including at least one pump by supplying pressure from an accumulator to a hydraulic braking system including a brake. The method can also include starting the engine coupled to the hydraulic fracturing pumping system and releasing the brake.

An internal combustion engine oil utilization system, comprising one or more oil pumps to receive and discharge engine oil including an engine oil circulation loop comprising a first flow path and a second flow path. The first flow path receives at least a portion of the oil discharged from the one or more oil pumps and utilizes the oil to lubricate the engine during running operation of the engine. The second flow path receives at least a portion of the oil discharged from the one or more oil pumps and accumulates the oil to start the engine and/or to lubricate the engine during at least one of a pre-starting operation and a starting operation of the engine.

An internal combustion engine, a method of operating the internal combustion engine, and a controller are disclosed. The method may comprise measuring a first pressure at a first position in a fluid line containing pressurized fluid; comparing the first pressure to a first threshold; in response to the first pressure exceeding the first threshold, transmitting a signal to depressurize the fluid line; after transmitting the signal to depressurize the fluid line, measuring a second pressure in the fluid line and comparing the second pressure to at least one of a second threshold and a third threshold, the second threshold being greater than the third threshold and less than the first threshold; and in response to the second pressure being less than the second threshold and exceeding the third threshold, transmitting another signal to depressurize the fluid line.

An internal combustion engine, a method of operating the internal combustion engine, and a controller are disclosed. The method may comprise measuring a first pressure at a first position in a fluid line containing pressurized fluid; comparing the first pressure to a first threshold; in response to the first pressure exceeding the first threshold, transmitting a signal to depressurize the fluid line; after transmitting the signal to depressurize the fluid line, measuring a second pressure in the fluid line and comparing the second pressure to at least one of a second threshold and a third threshold, the second threshold being greater than the third threshold and less than the first threshold; and in response to the second pressure being less than the second threshold and exceeding the third threshold, transmitting another signal to depressurize the fluid line.

A drive train (1) includes an internal combustion engine (2) and working hydraulics (4) having at least one hydraulic pump (7). When operated as a pump, the hydraulic pump (7) sucks hydraulic fluid from a tank (9) and delivers into a delivery line (10) that leads to the working hydraulics (4). When operated as a motor, the hydraulic pump (7) is supplied with hydraulic fluid from a hydraulic accumulator (25). The drive train (1) has a charge pump (20) to supply a charging circuit (23). The charge pump (20), when operated as a pump, sucks hydraulic fluid out of the tank (9) and delivers into a charge pressure line (22) that leads to a charging circuit (23), and the charge pump (20) when operated as a motor is supplied with hydraulic fluid from the hydraulic accumulator (25).

A drive train (1) includes an internal combustion engine (2) and working hydraulics (4) having at least one hydraulic pump (7). When operated as a pump, the hydraulic pump (7) sucks hydraulic fluid from a tank (9) and delivers into a delivery line (10) that leads to the working hydraulics (4). When operated as a motor, the hydraulic pump (7) is supplied with hydraulic fluid from a hydraulic accumulator (25). The drive train (1) has a charge pump (20) to supply a charging circuit (23). The charge pump (20), when operated as a pump, sucks hydraulic fluid out of the tank (9) and delivers into a charge pressure line (22) that leads to a charging circuit (23), and the charge pump (20) when operated as a motor is supplied with hydraulic fluid from the hydraulic accumulator (25).

A damper device includes: an input element coupled to an engine via a clutch; an intermediate element; an output element coupled to an input shaft of a transmission; a first elastic body that is disposed between the input element and the intermediate element; and a second elastic body that is disposed between the intermediate element and the output element and that acts in series with the first elastic body. When a total moment of inertia of the output element and a rotation element that rotates integrally with the output element on the engine side with respect to the input shaft is J.sub.2, and a total moment of inertia of all rotation members included between the input shaft and a differential gear coupled to an output shaft of the transmission is J.sub.TM, 0.12≤J.sub.2/(J.sub.2+J.sub.TM)≤0.5 is satisfied.

A damper device includes: an input element coupled to an engine via a clutch; an intermediate element; an output element coupled to an input shaft of a transmission; a first elastic body that is disposed between the input element and the intermediate element; and a second elastic body that is disposed between the intermediate element and the output element and that acts in series with the first elastic body. When a total moment of inertia of the output element and a rotation element that rotates integrally with the output element on the engine side with respect to the input shaft is J.sub.2, and a total moment of inertia of all rotation members included between the input shaft and a differential gear coupled to an output shaft of the transmission is J.sub.TM, 0.12≤J.sub.2/(J.sub.2+J.sub.TM)≤0.5 is satisfied.

A hydraulic start system and methods for operating an engine starter with the same is disclosed. The hydraulic start system may include an accumulator and at least two pumps fluidly coupled with and disposed upstream of the accumulator. The hydraulic start system may also include a first directional valve fluidly coupled with and disposed downstream of the accumulator and upstream of the engine starter. The hydraulic start system may further include a second directional valve fluidly coupled with and disposed downstream of the accumulator and upstream of the engine starter and the first directional valve. The second directional valve may be configured to direct at least a portion of the pressurized hydraulic fluid from the accumulator to the first directional valve to actuate the first directional valve to an open position.