An engine system and method for improving sampling of a port throttle pressure sensor. In one example, the port throttle pressure sensor is sampled a plurality of times during a cylinder cycle and different engine operating conditions are determined from selected samples. The system and method may improve engine air-fuel control as well as engine diagnostics.

Methods and systems are provided for the estimation of an aircharge into a cylinder used to adjust an engine operating parameter, based on a manifold pressure signal stored in a buffer. In one example, a method may include sampling an intake manifold pressure sensor signal at even increments of time, stamping it with its corresponding crank angle and storing it in a buffer. The closest stored signal to the intake valve closing of a cylinder may be used to calculate its aircharge.

An engine assembly includes an intake manifold and a manifold absolute pressure sensor configured to generate a current measured manifold absolute pressure (MAP.sub.M) signal for the intake manifold. The assembly includes a throttle valve adjustable to control airflow to the intake manifold and a throttle position sensor configured to generate a current measured throttle position (TP.sub.M) signal. A controller is operatively connected to the throttle valve and the manifold absolute pressure sensor and has a processor and tangible, non-transitory memory on which is recorded instructions for executing a method for determining a predicted manifold absolute pressure (MAP.sub.P). Execution of the instructions by the processor causes the controller to determine the predicted manifold absolute pressure (MAP.sub.P) based at least partially on a predicted throttle flow (TF.sub.P) and the current measured manifold absolute pressure (MAP.sub.M) signal.

A method for estimating pressures at a gas engine using a real-time model-based observer is implemented by a pressure estimation computing device. The method includes receiving a design schema describing an intake manifold and a plurality of components associated with the gas engine, segmenting the design schema into a plurality of segments defining a plurality of sections of the gas engine, defining a fluid dynamics model associated with each of the plurality of segments, defining a plurality of interconnected elements based on the plurality of fluid dynamics models, receiving at least one pressure measurement from at least one of a plurality of sensors associated with each of the sections of the gas engine, estimating a plurality of pressure values at each section of the gas engine, and controlling fuel injection to at least one gas cylinder based on the estimated plurality of pressure values.

A control device calculates an estimate of negative intake pressure based on the relationship between the rotation speed of a crankshaft and a throttle opening degree (Step S24). Then, the control device sets the estimate PE of the negative intake pressure, which is calculated in Step S24, to a greater value as combustion efficiency of CNG used in engine operation becomes higher (Step S25). When the corrected estimate PE of the negative intake pressure becomes smaller than or equal to a reference value PTh (Step S26: YES), the control device starts a negative pressure recovery procedure (Step S27).

A method is provided for controlling a filling (rl) of an internal combustion engine (2) including the camshaft phase adjustment in the case of a predefined setpoint filling (rlsol), including the following steps: carrying out the filling control based on an indicated pressure difference for obtaining a control variable (.sub.Fuereg) for setting an air mass supply to the internal combustion engine (2); and ascertaining the indicated pressure difference (p.sub.SR) as a difference between a predicted intake manifold pressure (p.sub.srpred) and an actual intake manifold pressure (p.sub.SR), the predicted intake manifold pressure (p.sub.srpred) corresponding to an intake manifold pressure which is necessary for reaching the setpoint filling (rlsol) at an aspiration curve which is predicted for a predefined time constant ().

In the control device, a relationship of a throttle-upstream pressure with respect to an exhaust-gas amount is used in a state where a supercharge pressure becomes the lowest by a WG-instruction value with respect to a WGV-control component 220 for driving a WGV 33a provided at a bypass passage 33 bypassing a turbocharger 32, and a relationship of a throttle-upstream pressure with respect to an aperture of a throttle valve 23, a rotational speed of an engine, and an intake-manifold pressure is used, and any of the throttle-upstream pressures, whichever is higher, being calculated in accordance with each of the relationship, is defined as a throttle-upstream-estimation value, whereby the throttle-upstream pressure is estimated by a cheap means with high accuracy so as to control the engine.

A target engine speed module selectively sets M target engine speeds for M future times, respectively, based on one of increasing and decreasing an engine speed. A prediction module, based on a set of possible target values for the M future times and a model of an engine, determines M predicted engine speeds for the M future times, respectively. A cost module determines a cost for the set of possible target values based on comparisons of the M predicted engine speeds for the M future times with the M target engine speeds for the M future times, respectively. A selection module, based on the cost, selects the set of possible target values from a group including the set of possible target values and N other sets of possible target values, and sets target values based on the selected set of possible target values. An actuator module controls an engine actuator based on a first one of the target values.

A control apparatus for an internal combustion engine comprises a throttle upstream pressure estimation unit which calculates, based on an AFS intake air amount from an AFS and an intake manifold pressure, an average density ave(n) in a region combining a supercharged portion from a downstream of a compressor to an upstream of a throttle valve and an intake manifold, and estimates a throttle upstream pressure based on the intake manifold pressure and the average density ave(n). Further, the throttle upstream pressure estimation unit learns a relationship between a throttle opening degree and an effective opening area to correct a throttle upstream pressure estimated value (estimated P2) based on a range of a throttle opening degree learning value, the throttle opening degree learning value, and a dispersion of the actual throttle opening degree error.

A method for detecting errors in a sensor at a gas cylinder is implemented by a pressure estimation computing device including a processor and a memory device coupled to the processor. The method includes receiving a first pressure measurement from a first sensor associated with a gas cylinder, receiving a design schema describing an intake manifold, the intake manifold included within the gas engine, segmenting the design schema into a plurality of segments, defining a fluid dynamics model associated with each of the plurality of segments, defining a plurality of interconnected 2-port elements based on the plurality of fluid dynamics models, estimating a second pressure measurement for the gas cylinder based on the plurality of interconnected 2-port elements, comparing the first pressure measurement to the second pressure measurement, and determining that the first sensor is in an anomalous state.