A test system for examining a hollow body, in particular a cylinder bore in an engine block, comprises a measuring apparatus comprising an elongate body and a plurality of sensors which are connected to the body and are set up to carry out a distance measurement. The test system also comprises electronic control means which are set up to move the measuring apparatus into a hollow body to be examined and to determine an internal diameter of the hollow body on the basis of distance measurement data from the sensors. In order to examine hollow bodies of different diameters, at least some of the sensors are in the form of movable sensors which can be moved relative to the elongate body of the measuring apparatus. The electronic control means are also set up to select a measuring position of the movable sensors relative to the elongate body on the basis of a hollow body to be examined. A calibration station is provided and the electronic control means are set up to carry out a calibration process for the movable sensors. A corresponding method is also disclosed.

According to the invention, a diagnostic system is provided for diagnosing a misfire condition is provided of individual engine cylinders in a turbocharged diesel engine having at least a first and a second cylinder associated with a common exhaust path. The system comprises a pressure sensor in an exhaust path, for measuring a pressure value; a crankshaft position sensor, for detecting a rotational crankshaft position; and a processor unit for reading the pressure sensor and the crankshaft position sensor. The processor unit is arranged for performing acts of: sampling pressure values of the pressure sensor in the common exhaust path as a function of crankshaft angle position; attributing for each cylinder fired in succession at least two sampling values (P.sub.α, P.sub.β) for at least two successive crankshaft angle positions of a pressure pulse during a cylinder firing operation; determining a boundary for a coordinate (P.sub.α, P.sub.β) formed by a tuple of sampling values (P.sub.α, P.sub.β); diagnosing a misfire condition if the coordinate formed by said tuple of sampling values is outside the boundary.

The present invention relates to a rotary jig for rotation of a crank shaft of a vehicle and a measuring system using the same. The measuring system includes: a rotary jig (100) for rotating a crank shaft (C) by opening only a bonnet in a vehicle stop state; a probe (700) joined to the position where a spark plug of an engine is separated and having an extension rod located at the center of a piston to check a top dead point and to output signal values when the crank shaft is rotated according to rotation of the rotary jig; a pump (810) for supplying air to a cylinder chamber of the engine through a tube connected to the probe (700) to move the piston; a terminal (900) for outputting the signal value of the probe (700) to a display unit through wireless communication; and a control unit (800) for controlling the signal values.

The measuring system can rotate the crank shaft after a worker opens only a bonnet and mounts the rotary jig at an end portion of the crank shaft when the crank shaft is rotated, thereby enabling the worker to simply measure an operational state of the engine linked with the crank shaft.

It is provided a portable tester for leakage rate of a cylinder of an automobile engine. The portable tester includes a shell; wherein a circuit board and a manifold body are provided in the shell; a throttle hole is provided inside the manifold body, the shell includes a front shell and a rear shell; a display and a control key are provided respectively at an upper end of and at a middle part of the front shell; the circuit board is provided with a decoding drive electrically connected with the display, and a single chip microcomputer unit is provided on the decoding drive and electrically connected with the control key; an air inlet connecter and an air outlet connector are provided at the lower end of the front shell. Two ends of the manifold body are provided with sensors electrically connected with the single chip microcomputer unit.

It is provided a portable tester for leakage rate of a cylinder of an automobile engine. The portable tester includes a shell; wherein a circuit board and a manifold body are provided in the shell; a throttle hole is provided inside the manifold body, the shell includes a front shell and a rear shell; a display and a control key are provided respectively at an upper end of and at a middle part of the front shell; the circuit board is provided with a decoding drive electrically connected with the display, and a single chip microcomputer unit is provided on the decoding drive and electrically connected with the control key; an air inlet connecter and an air outlet connector are provided at the lower end of the front shell. Two ends of the manifold body are provided with sensors electrically connected with the single chip microcomputer unit.

An engine test method that causes a computer to execute a process including, acquiring, by a processer on the computer, a first test pattern in which an operation variable that is used for an engine test is changed in time series, inputting, based on the first test pattern, a first operation variable to a mathematical model that represents a time series response of an engine obtained by inputting a test pattern as a simulation of the engine test, monitoring, as a first monitoring parameter of engine abnormality, at least one of an air excess ratio, pressure and temperature of an intake manifold, pressure and temperature of an exhaust manifold, and a maximum cylinder pressure rise rate that are obtained by inputting the first operation variable to the mathematical model, holding, when the first monitoring parameter exceeds a first threshold value, the first operation variable until the first monitoring parameter is less than the first threshold value, creating, a history of the first operation variable in the simulation as a second test pattern, monitoring, as a second monitoring parameter, at least one of the air excess ratio, the pressure and the temperature of the intake manifold, the pressure and the temperature of the exhaust manifold, and the maximum cylinder pressure rise rate that are obtained by inputting a second operation variable to a real engine based on the second test pattern, holding, when the second monitoring parameter exceeds a second threshold value, the second operation variable until the second monitoring parameter is less than the second threshold value, and acquiring, time series data of the second operation variable and a controlled variable.

When a diesel engine is determined to be in a motoring state, a hysteresis zero angle H.sub.0 is determined (step S14). Subsequently, a gradient d.sub.n is calculated (step S16). The gradient d.sub.n is calculated based on data (θ.sub.n, Δh.sub.n) of a deviation Δh.sub.n at a retardation side from the hysteresis zero angle H.sub.0 and at an advance side from a predetermined crank angle. Subsequently, the gradient d.sub.n and the hysteresis zero angle H.sub.0 are updated (step S18). When the diesel engine is determined to be in a non-motoring state, data (θ.sub.n, P.sub.n) of an actual in-cylinder pressure is corrected based on a newest correction coefficient η and hysteresis zero angle H.sub.0 (step S22).

Disclosed is a method for determining the engine torque delivered by a multi-cylinder engine, including the following steps: determining the angular velocity of the crankshaft and measuring the cylinder pressure over an angular window of combustion in a first cylinder fitted with a cylinder pressure sensor; calculating the value of the engine torque (TQI.sub.ref) in this window; determining a current transfer function for the learning of the torque, so as to estimate the torque TQI.sub.mdl(cyl)) in a second cylinder not fitted with a cylinder pressure sensor, from the product of: the engine torque calculated over the angular window of the first cylinder, a ratio between: the angular velocity of the crankshaft over an angular window of combustion of the second cylinder, and the angular velocity of the crankshaft over the window of combustion of the first cylinder.

Disclosed is a method for determining the engine torque delivered by a multi-cylinder engine, including the following steps: determining the angular velocity of the crankshaft and measuring the cylinder pressure over an angular window of combustion in a first cylinder fitted with a cylinder pressure sensor; calculating the value of the engine torque (TQI.sub.ref) in this window; determining a current transfer function for the learning of the torque, so as to estimate the torque TQI.sub.mdl(cyl)) in a second cylinder not fitted with a cylinder pressure sensor, from the product of: the engine torque calculated over the angular window of the first cylinder, a ratio between: the angular velocity of the crankshaft over an angular window of combustion of the second cylinder, and the angular velocity of the crankshaft over the window of combustion of the first cylinder.

A method for determining the recycled air flow rate and oxygen quantity at the inlet of an internal combustion engine cylinder. The method involves measuring pressure in each cylinder during a compression phase and calculating the mass of gas in each cylinder based on the measured pressure, volume and temperature variation for an angular variation of the crankshaft, heat capacity, and heat losses. The method further involves determining the mass of gas in all cylinders over a full combustion cycle as well as in the recycled exhaust.