A method for diagnosing an engine in a vehicle, the method comprising: initiating a diagnostic test of the engine, disabling a cylinder of the engine, measuring a parameter indicative of performance of the engine, re-enabling the cylinder, comparing the parameter to reference data, assessing a status of the cylinder based on the comparison, and generating a diagnostic result based on the status of the disabled cylinder.

A resonance suppression control circuit provides operation stable for variations with a low order mode of vibration and suppressing spill-over due to high order mode of vibration. This circuit controls a physical system having two or more modes of vibration, and suppresses resonance in a lowest order mode of vibration from among the plurality of modes. The circuit has a controller designed by a design method, using a generalized plant with nominal model, and structured perturbation to the generalized plant. The nominal model is represented by the product of a low order vibration mode transfer function having the low order mode of vibration to be suppressed, and a high order vibration mode transfer function having a high order mode of vibration. The structured perturbation includes a first parameter perturbation term which imparts a multiplicative error to a spring constant included in the vibration mode transfer function being suppressed.

In a test run, in order to easily provide a high-quality propulsion torque of a torque generator based on the partially low-quality measured variables available on the test bench, it is foreseen that an inner torque (M.sub.i) of the torque generator (D) is measured and based on the measured inner torque (M.sub.i), from an equation of motion, including the measured inner torque (M.sub.i), a dynamic torque (M.sub.dyn) and a shaft torque (M.sub.w) measured on the output shaft of the torque generator (D), a correction torque ({circumflex over (M)}.sub.cor) is estimated, and from the estimated correction torque ({circumflex over (M)}.sub.cor) and the measured inner torque (M.sub.i), the propulsion torque (M.sub.v) according to the relation M.sub.v={circumflex over (M)}.sub.cor+M.sub.i is computed.

An engine brake test tool includes a fitting configured to be secured within a valve opening in an engine brake system, wherein the fitting includes a first opening configured to be placed into fluid communication with a pressurized fluid source and a second opening configured to be placed into fluid communication with an oil outlet line leading to a slave piston of an engine brake system.

A test method includes deriving road grade information or wind load information from test schedule torque outputs generated by a dynamometer operatively arranged with a first vehicle, and controlling an accelerator pedal, an accelerator pedal signal, a fuel injector, a manifold pressure, a motor controller, or a throttle valve associated with the first or a second vehicle according to a speed schedule such that the dynamometer, or another dynamometer, programmed with the road grade information or wind load information and operatively arranged with the first or second vehicle applies a load to the first or second vehicle that reflects the road grade information or wind load information.

A resonance suppression control circuit provides operation stable for variations with a low order mode of vibration and suppressing spill-over due to high order mode of vibration. This circuit controls a physical system having two or more modes of vibration, and suppresses resonance in a lowest order mode of vibration from among the plurality of modes. The circuit has a controller designed by a design method, using a generalized plant with nominal model, and structured perturbation to the generalized plant. The nominal model is represented by the product of a low order vibration mode transfer function having the low order mode of vibration to be suppressed, and a high order vibration mode transfer function having a high order mode of vibration. The structured perturbation includes a first parameter perturbation term which imparts a multiplicative error to a spring constant included in the vibration mode transfer function being suppressed.

A method for detecting an improper opening of a multiple suction reciprocating compressor suction valve of a reciprocating compressor includes monitoring, by an electronic processing core, a variable proportional to torque of an electrical engine that cooperates with a piston of the reciprocating compressor, the variable being measured by a sensor. A detection of the improper opening of the suction valve is made by a detection of at least one peak of the variable proportional to torque of the electrical engine during power of the electromagnetic field generator element.

A test method for a vehicle powertrain includes, during a first test of a first vehicle or a portion of a first vehicle on a dynamometer, coordinatingly controlling (i) an accelerator pedal, an accelerator pedal signal, a fuel injector, a manifold pressure, a motor controller, or a throttle valve according to a load schedule and (ii) the dynamometer according to a speed schedule such that the dynamometer applies dynamic torque that causes a powertrain of the first vehicle or portion of the first vehicle to produce dynamic powertrain torque. The test method also includes recording values defining a history of the dynamic torque, and during a second test of the first vehicle or portion of the first vehicle on the dynamometer or another dynamometer, or during a second test of a second vehicle or a portion of a second vehicle on the dynamometer or another dynamometer, coordinatingly controlling (iii) an accelerator pedal, an accelerator pedal signal, a fuel injector, a manifold pressure, a motor controller, or a throttle valve according to the values defining the history of the dynamic torque and (iv) the dynamometer or the another dynamometer according to the speed schedule such that the dynamometer or the another dynamometer applies dynamic torque that causes a powertrain of the first vehicle or portion of the first vehicle or a powertrain of the second vehicle or portion of the second vehicle to reproduce the dynamic powertrain torque.

The present invention relates to A power margin indicator device constituting a first limitation indicator for a rotorcraft, for providing a pilot of said rotorcraft with information about a power margin available on at least one engine and a main power transmission gearbox of said rotorcraft as a function of flying conditions, said device comprising: input means for collecting input data corresponding various operating parameters of said at least one engine and of said MGB; calculation means connected to said input means, said calculation means serving to determine a collective pitch margin for the blades of a rotor of said rotorcraft; and display means presenting said collective pitch margin.

The purpose of the present invention is to provide a device for controlling a dynamometer of a test system, wherein the device is capable of controlling shaft torque to a prescribed target torque while minimizing low-frequency-range resonance caused by viscous drag of a test piece. This test system is provided with a dynamometer joined to an engine via a coupling shaft, an inverter for supplying electric power to the dynamometer, a shaft torque meter for detecting the shaft torque produced in the coupling shaft, and a dynamometer-controlling device 6 for generating a torque-current command signal T2 that is sent to the inverter and is generated on the basis of a shaft torque detection signal T12 from the shaft torque meter. The dynamometer-controlling device 6 is provided with an integrator 62 for integrating the difference between the shaft torque detection signal 12 and a shaft torque command signal T12ref, and a phase lead compensator 63 for accepting an output signal from the integrator 62 as an input and performing a phase lead compensation process that uses constants (a1, b1) that are dependent on the viscous drag of the test piece. An output signal from the phase lead compensator 63 is used to generate the torque-current command signal T2.