Volumetric efficiency determination systems and methods

A cylinder control system of a vehicle, includes a cylinder control module and a volumetric efficiency (VE) module. The cylinder control module determines a desired cylinder activation/deactivation sequence. The cylinder control module also activates and deactivates valves of cylinders of an engine based on the desired cylinder activation/deactivation sequence. The VE module determines a volumetric efficiency based on a cylinder activation/deactivation sequence of the last Q cylinders in the firing order. Q is an integer greater than one.

FIELD

The present disclosure relates to internal combustion engines and more specifically to engine control systems and methods.

BACKGROUND

Internal combustion engines combust an air and fuel mixture within cylinders to drive pistons, which produces drive torque. In some types of engines, air flow into the engine may be regulated via a throttle. The throttle may adjust throttle area, which increases or decreases air flow into the engine. As the throttle area increases, the air flow into the engine increases. A fuel control system adjusts the rate that fuel is injected to provide a desired air/fuel mixture to the cylinders and/or to achieve a desired torque output. Increasing the amount of air and fuel provided to the cylinders increases the torque output of the engine.

Under some circumstances, one or more cylinders of an engine may be deactivated. Deactivation of a cylinder may include deactivating opening and closing of intake valves of the cylinder and halting fueling of the cylinder. One or more cylinders may be deactivated, for example, to decrease fuel consumption when the engine can produce a requested amount of torque while the one or more cylinders are deactivated.

SUMMARY

A cylinder control system of a vehicle, includes a cylinder control module and a volumetric efficiency (VE) module. The cylinder control module determines a desired cylinder activation/deactivation sequence. The cylinder control module also activates and deactivates valves of cylinders of an engine based on the desired cylinder activation/deactivation sequence. The VE module determines a volumetric efficiency based on a cylinder activation/deactivation sequence of the last Q cylinders in the firing order. Q is an integer greater than one.

In other features, a cylinder control method includes: determining a desired cylinder activation/deactivation sequence; and activating and deactivating valves of cylinders of an engine based on the desired cylinder activation/deactivation sequence. The cylinder control method further includes determining a volumetric efficiency (VE) based on a cylinder activation/deactivation sequence of the last Q cylinders in the firing order. Q is an integer greater than one.

DETAILED DESCRIPTION

Internal combustion engines combust an air and fuel mixture within cylinders to generate torque. Under some circumstances, an engine control module (ECM) may deactivate one or more cylinders of the engine. The ECM may deactivate one or more cylinders, for example, to decrease fuel consumption when the engine can produce a requested amount of torque while the one or more cylinders are deactivated. Deactivation of a cylinder may include deactivating opening and closing of intake valves of the cylinder and halting fueling of the cylinder.

The ECM of the present disclosure determines a desired activation/deactivation sequence for the cylinders. The ECM may determine the desired activation/deactivation sequence, for example, to optimize fuel efficiency, drive quality, and/or noise and vibration (N&V) under the operating conditions. The ECM activates and deactivates cylinders of the engine according to the desired activation/deactivation sequence.

The ECM predicts an amount of air that will be trapped within a next activated cylinder in a predetermined firing order of the cylinders. The ECM also predicts an amount of air that will be trapped within a second activated cylinder following the next activated cylinder in the firing order. One or more engine operating parameters, such as spark timing, fueling, throttle opening, valve phasing, and/or boost, may be regulated based on one or both of the predicted amounts.

The ECM determines the predicted amounts based on a volumetric efficiency (VE). The sequence in which the cylinders are activated and deactivated, however, may affect the VE. The ECM therefore determines the VE based on the cylinder activation/deactivation sequence used for the last Q cylinders in the firing order, where Q is an integer greater than one.

Referring now toFIG. 1, a functional block diagram of an example engine system100is presented. The engine system100of a vehicle includes an engine102that combusts an air/fuel mixture to produce torque based on driver input from a driver input module104. Air is drawn into the engine102through an intake system108. The intake system108may include an intake manifold110and a throttle valve112. For example only, the throttle valve112may include a butterfly valve having a rotatable blade. An engine control module (ECM)114controls a throttle actuator module116, and the throttle actuator module116regulates opening of the throttle valve112to control airflow into the intake manifold110.

Air from the intake manifold110is drawn into cylinders of the engine102. While the engine102includes multiple cylinders, for illustration purposes a single representative cylinder118is shown. For example only, the engine102may include 2, 3, 4, 5, 6, 8, 10, and/or 12 cylinders. The ECM114may instruct a cylinder actuator module120to selectively deactivate some of the cylinders under some circumstances, as discussed further below, which may improve fuel efficiency.

The engine102may operate using a four-stroke cycle. The four strokes, described below, will be referred to as the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke. During each revolution of a crankshaft (not shown), two of the four strokes occur within the cylinder118. Therefore, two crankshaft revolutions are necessary for the cylinder118to experience all four of the strokes. For four-stroke engines, one engine cycle may correspond to two crankshaft revolutions.

When the cylinder118is activated, air from the intake manifold110is drawn into the cylinder118through an intake valve122during the intake stroke. The ECM114controls a fuel actuator module124, which regulates fuel injection to achieve a desired air/fuel ratio. Fuel may be injected into the intake manifold110at a central location or at multiple locations, such as near the intake valve122of each of the cylinders. In various implementations (not shown), fuel may be injected directly into the cylinders or into mixing chambers/ports associated with the cylinders. The fuel actuator module124may halt injection of fuel to cylinders that are deactivated.

The injected fuel mixes with air and creates an air/fuel mixture in the cylinder118. During the compression stroke, a piston (not shown) within the cylinder118compresses the air/fuel mixture. The engine102may be a compression-ignition engine, in which case compression causes ignition of the air/fuel mixture. Alternatively, the engine102may be a spark-ignition engine, in which case a spark actuator module126energizes a spark plug128in the cylinder118based on a signal from the ECM114, which ignites the air/fuel mixture. Some types of engines, such as homogenous charge compression ignition (HCCI) engines may perform both compression ignition and spark ignition. The timing of the spark may be specified relative to the time when the piston is at its topmost position, which will be referred to as top dead center (TDC).

The spark actuator module126may be controlled by a timing signal specifying how far before or after TDC to generate the spark. Because piston position is directly related to crankshaft rotation, operation of the spark actuator module126may be synchronized with the position of the crankshaft. The spark actuator module126may halt provision of spark to deactivated cylinders or provide spark to deactivated cylinders.

During the combustion stroke, the combustion of the air/fuel mixture drives the piston down, thereby driving the crankshaft. The combustion stroke may be defined as the time between the piston reaching TDC and the time at which the piston returns to a bottom most position, which will be referred to as bottom dead center (BDC).

During the exhaust stroke, the piston begins moving up from BDC and expels the byproducts of combustion through an exhaust valve130. The byproducts of combustion are exhausted from the vehicle via an exhaust system134.

The intake valve122may be controlled by an intake camshaft140, while the exhaust valve130may be controlled by an exhaust camshaft142. In various implementations, multiple intake camshafts (including the intake camshaft140) may control multiple intake valves (including the intake valve122) for the cylinder118and/or may control the intake valves (including the intake valve122) of multiple banks of cylinders (including the cylinder118). Similarly, multiple exhaust camshafts (including the exhaust camshaft142) may control multiple exhaust valves for the cylinder118and/or may control exhaust valves (including the exhaust valve130) for multiple banks of cylinders (including the cylinder118). While camshaft based valve actuation is shown and has been discussed, camless valve actuators may be implemented.

The cylinder actuator module120may deactivate the cylinder118by disabling opening of the intake valve122and/or the exhaust valve130. The time at which the intake valve122is opened may be varied with respect to piston TDC by an intake cam phaser148. The time at which the exhaust valve130is opened may be varied with respect to piston TDC by an exhaust cam phaser150. A phaser actuator module158may control the intake cam phaser148and the exhaust cam phaser150based on signals from the ECM114. When implemented, variable valve lift (not shown) may also be controlled by the phaser actuator module158. In various other implementations, the intake valve122and/or the exhaust valve130may be controlled by actuators other than a camshaft, such as electromechanical actuators, electrohydraulic actuators, electromagnetic actuators, etc.

The engine system100may include a boost device that provides pressurized air to the intake manifold110. For example,FIG. 1shows a turbocharger including a turbine160-1that is driven by exhaust gases flowing through the exhaust system134. The turbocharger also includes a compressor160-2that is driven by the turbine160-1and that compresses air leading into the throttle valve112. In various implementations, a supercharger (not shown), driven by the crankshaft, may compress air from the throttle valve112and deliver the compressed air to the intake manifold110.

A wastegate162may allow exhaust to bypass the turbine160-1, thereby reducing the boost (the amount of intake air compression) of the turbocharger. The ECM114may control the turbocharger via a boost actuator module164. The boost actuator module164may modulate the boost of the turbocharger by controlling the position of the wastegate162. In various implementations, multiple turbochargers may be controlled by the boost actuator module164. The turbocharger may have variable geometry, which may be controlled by the boost actuator module164.

An intercooler (not shown) may dissipate some of the heat contained in the compressed air charge, which is generated as the air is compressed. Although shown separated for purposes of illustration, the turbine160-1and the compressor160-2may be mechanically linked to each other, placing intake air in close proximity to hot exhaust. The compressed air charge may absorb heat from components of the exhaust system134.

The engine system100may include an exhaust gas recirculation (EGR) valve170, which selectively redirects exhaust gas back to the intake manifold110. The EGR valve170may be located upstream of the turbocharger's turbine160-1. The EGR valve170may be controlled by an EGR actuator module172.

Crankshaft position may be measured using a crankshaft position sensor180. A temperature of engine coolant may be measured using an engine coolant temperature (ECT) sensor182. The ECT sensor182may be located within the engine102or at other locations where the coolant is circulated, such as a radiator (not shown).

A pressure within the intake manifold110may be measured using a manifold absolute pressure (MAP) sensor184. In various implementations, engine vacuum, which is the difference between ambient air pressure and the pressure within the intake manifold110, may be measured. A mass flow rate of air flowing into the intake manifold110may be measured using a mass air flow (MAF) sensor186. In various implementations, the MAF sensor186may be located in a housing that also includes the throttle valve112.

Position of the throttle valve112may be measured using one or more throttle position sensors (TPS)190. A temperature of air being drawn into the engine102may be measured using an intake air temperature (IAT) sensor192. The engine system100may also include one or more other sensors193. The ECM114may use signals from the sensors to make control decisions for the engine system100.

The ECM114may communicate with a transmission control module194to coordinate shifting gears in a transmission (not shown). For example, the ECM114may reduce engine torque during a gear shift. The engine102outputs torque to a transmission (not shown) via the crankshaft. One or more coupling devices, such as a torque converter and/or one or more clutches, regulate torque transfer between a transmission input shaft and the crankshaft. Torque is transferred between the transmission input shaft and a transmission output shaft via the gears.

Torque is transferred between the transmission output shaft and wheels of the vehicle via one or more differentials, driveshafts, etc. Wheels that receive torque output by the transmission may be referred to as driven wheels. Wheels that do not receive torque from the transmission may be referred to as undriven wheels.

The ECM114may communicate with a hybrid control module196to coordinate operation of the engine102and an electric motor198. The electric motor198may also function as a generator, and may be used to produce electrical energy for use by vehicle electrical systems and/or for storage in a battery. While only the electric motor198is shown and discussed, multiple electric motors may be implemented. In various implementations, various functions of the ECM114, the transmission control module194, and the hybrid control module196may be integrated into one or more modules.

Each system that varies an engine parameter may be referred to as an engine actuator. Each engine actuator has an associated actuator value. For example, the throttle actuator module116may be referred to as an engine actuator, and the throttle opening area may be referred to as the actuator value. In the example ofFIG. 1, the throttle actuator module116achieves the throttle opening area by adjusting an angle of the blade of the throttle valve112.

The spark actuator module126may also be referred to as an engine actuator, while the corresponding actuator value may be the amount of spark advance relative to cylinder TDC. Other engine actuators may include the cylinder actuator module120, the fuel actuator module124, the phaser actuator module158, the boost actuator module164, and the EGR actuator module172. For these engine actuators, the actuator values may correspond to a cylinder activation/deactivation sequence, fueling rate, intake and exhaust cam phaser angles, boost pressure, and EGR valve opening area, respectively. The ECM114may control the actuator values in order to cause the engine102to generate a desired engine output torque.

Referring now toFIG. 2, a functional block diagram of an example engine control system is presented. A torque request module204may determine a torque request208based on one or more driver inputs212, such as an accelerator pedal position, a brake pedal position, a cruise control input, and/or one or more other suitable driver inputs. The torque request module204may determine the torque request208additionally or alternatively based on one or more other torque requests, such as torque requests generated by the ECM114and/or torque requests received from other modules of the vehicle, such as the transmission control module194, the hybrid control module196, a chassis control module, etc.

One or more engine actuators may be controlled based on the torque request208and/or one or more other parameters. For example, a throttle control module216may determine a desired throttle opening220based on the torque request208. The throttle actuator module116may adjust opening of the throttle valve112based on the desired throttle opening220.

A spark control module224may determine a desired spark timing228based on the torque request208. The spark actuator module126may generate spark based on the desired spark timing228. A fuel control module232may determine one or more desired fueling parameters236based on the torque request208. For example, the desired fueling parameters236may include fuel injection amount, number of fuel injections for injecting the amount, and timing for each of the injections. The fuel actuator module124may inject fuel based on the desired fueling parameters236.

A phaser control module237may determine desired intake and exhaust cam phaser angles238and239based on the torque request208. The phaser actuator module158may regulate the intake and exhaust cam phasers148and150based on the desired intake and exhaust cam phaser angles238and239, respectively. A boost control module240may determine a desired boost242based on the torque request208. The boost actuator module164may control boost output by the boost device(s) based on the desired boost242.

A cylinder control module244determines a desired cylinder activation/deactivation sequence248based on the torque request208. The cylinder actuator module120deactivates the intake and exhaust valves of the cylinders that are to be deactivated according to the desired cylinder activation/deactivation sequence248. The cylinder actuator module120allows opening and closing of the intake and exhaust valves of cylinders that are to be activated according to the desired cylinder activation/deactivation sequence248.

Fueling is halted (zero fueling) to cylinders that are to be deactivated according to the desired cylinder activation/deactivation sequence248, and fuel is provided to the cylinders that are to be activated according to the desired cylinder activation/deactivation sequence248. Spark is provided to the cylinders that are to be activated according to the desired cylinder activation/deactivation sequence248. Spark may be provided or halted to cylinders that are to be deactivated according to the desired cylinder activation/deactivation sequence248. Cylinder deactivation is different than fuel cutoff (e.g., deceleration fuel cutoff) in that the intake and exhaust valves of cylinders to which fueling is halted during fuel cutoff are still opened and closed during the fuel cutoff whereas the intake and exhaust valves are maintained closed when deactivated.

In various implementations, N (number of) predetermined cylinder activation/deactivation sequences are stored, such as in a sequence database. N is an integer greater than 2 and may be, for example, 3, 4, 5, 6, 7, 8, 9, 10, or another suitable value.

Each of the N predetermined cylinder activation/deactivation sequences includes one indicator for each of the next M events of a predetermined firing order of the cylinders. M may be an integer that is greater than the total number of cylinders of the engine102. For example only, M may be 20, 40, 60, 80, a multiple of the total number of cylinders of the engine, or another suitable number. In various implementations, M may be less than the total number of cylinders of the engine102. M may be calibratable and set based on, for example, the total number of cylinders of the engine102, engine speed, and/or torque.

Each of the M indicators indicates whether the corresponding cylinder in the firing order should be activated or deactivated. For example only, the N predetermined cylinder activation/deactivation sequences may each include an array including M (number of) zeros and/or ones. A zero may indicate that the corresponding cylinder should be activated, and a one may indicate that the corresponding cylinder should be deactivated, or vice versa.

The following cylinder activation/deactivation sequences are provided as examples of predetermined cylinder activation/deactivation sequences.
[0 1 0 1 0 1 . . . 0 1]  (1)
[0 0 1 0 0 1 . . . 0 0 1]  (2)
[0 0 0 1 0 0 0 1 . . . 0 0 0 1]  (3)
[0 0 0 0 0 0 . . . 0 0]  (4)
[1 1 1 1 1 1 . . . 1 1]  (5)
[0 1 1 0 1 1 . . . 0 1 1]  (6)
[0 0 1 1 0 0 1 1 . . . 0 0 1 1]  (7)
[0 1 1 1 0 1 1 1 . . . 0 1 1 1]  (8)
Sequence (1) corresponds to a repeating pattern of one cylinder in the firing order being activated, the next cylinder in the firing order being deactivated, the next cylinder in the firing order being activated, and so on. Sequence (2) corresponds to a repeating pattern of two consecutive cylinders in the firing order being activated, the next cylinder in the firing order being deactivated, the next two consecutive cylinders in the firing order being activated, and so on. Sequence (3) corresponds to a repeating pattern of three consecutive cylinders in the firing order being activated, the next cylinder in the firing order being deactivated, the next three consecutive cylinders in the firing order being activated, and so on. Sequence (4) corresponds to all of the cylinders being activated, and sequence (5) corresponds to all of the cylinders being deactivated. Sequence (6) corresponds to a repeating pattern of one cylinder in the firing order being activated, the next two consecutive cylinders in the firing order being deactivated, the next cylinder in the firing order being activated, and so on. Sequence (7) corresponds to a repeating pattern of two consecutive cylinders in the firing order being activated, the next two consecutive cylinders in the firing order being deactivated, the next two consecutive cylinders in the firing order being activated, and so on. Sequence (8) corresponds to a repeating pattern of one cylinder in the firing order being activated, the next three consecutive cylinders in the firing order being deactivated, the next cylinder in the firing order being activated, and so on.

While the 8 example cylinder activation/deactivation sequences have been provided above, numerous other cylinder activation/deactivation sequences are possible. Also, while repeating patterns have been provided as examples, one or more non-repeating cylinder activation/deactivation sequences may be included. While the N predetermined cylinder activation/deactivation sequences have been discussed as being stored in arrays, the N predetermined cylinder activation/deactivation sequences may be stored in another suitable form.

The cylinder control module244may select one of the N predetermined cylinder activation/deactivation sequences and set the desired cylinder activation/deactivation sequence248to the selected one of the N predetermined cylinder activation/deactivation sequences. In various implementations, the cylinder control module244may determine the desired cylinder activation/deactivation sequence248as opposed to setting the desired cylinder activation/deactivation sequence248to one of N predetermined cylinder activation/deactivation sequences. The cylinders of the engine102are activated or deactivated according to the desired cylinder activation/deactivation sequence248in the firing order. The desired cylinder activation/deactivation sequence248may be repeated until the desired cylinder activation/deactivation sequence248is changed.

An air per cylinder (APC) module252(see alsoFIG. 3) generates a predicted mass of air that will be trapped within the next (activated) cylinder in the firing order of the cylinders. The predicted mass of air that will be trapped within the next cylinder in the firing order will be referred to as a first predicted APC (APC1)256. The APC module252also generates a predicted mass of air that will be trapped within the next (activated) cylinder following the next (activated) cylinder in the firing order. The predicted mass of air that will be trapped within the cylinder following the next cylinder in the firing order will be referred to as a second predicted APC (APC2)258.

FIG. 3includes a functional block diagram of an example implementation of the APC module252. Referring now toFIGS. 2 and 3, the APC module252also determines a mass of air that is actually trapped within the present (activated) cylinder in the firing order. The mass of air trapped within the present cylinder in the firing order will be referred to as a measured APC260.

A measured APC module264determines the measured APC260. When in a steady-state condition, the measured APC module264may set the measured APC260equal to a MAF based APC268. The measured APC module264may determine the MAF based APC268based on a MAF272measured using the MAF sensor186. For example only, the MAF based APC268may be set equal to or based on an integral of the MAF272over a predetermined period. The steady-state condition may occur, for example, when a change in a pressure within the intake manifold110(e.g., a MAP276measured using the MAP sensor184) over a predetermined period is less than a predetermined amount.

The measured APC module264updates a volumetric efficiency (VE) correction (not shown) when in the steady-state condition. The measured APC module264determines the VE correction based on a temperature of the air trapped within the present cylinder (charge temperature)280, a volumetric efficiency (VE)284, an intake port pressure288, a cylinder volume, and the ideal (or universal) gas constant. The measured APC module264may determine the VE correction, for example, using one or more functions and/or mappings that relate the charge temperature280, the VE284, the intake port pressure288, the cylinder volume, and the ideal (or universal) gas constant to the VE correction.

For example, when in the steady-state condition, the measured APC module264may determine the VE correction using the equation:

VECorr=APCMAF*R*Tηe*Vcyl*Pint,(9)
where VECorr is the VE correction, APCMAFis the MAF based APC268, R is the ideal gas constant, T is the charge temperature280, ηeis the VE284, Vcylis the cylinder volume, and Pintis the intake port pressure288. The charge temperature280may be set equal to ambient air temperature or determined based on ambient air temperature and one or more other temperatures, such as engine coolant temperature (ECT). For example, the charge temperature280may be determined based on a weighted average of the ambient air temperature and the ECT, and the weighting may be set based on an APC. The cylinder volume and the ideal gas constants are predetermined values. The intake port pressure288corresponds to a predicted pressure within an intake port of the present cylinder at approximately intake valve closing. The intake port pressure288may be set equal to or determined based on, for example, a pressure within the intake manifold110(e.g., the MAP276) measured at a predetermined rotational distance before intake valve opening. The VE284is discussed further below.

When not in the steady-state condition, the measured APC module264may maintain the VE correction. In other words, when not in the steady-state condition, the measured APC module264may disable updating the VE correction as described above.

When not in the steady-state condition, the measured APC module264determines the measured APC260based on the VE correction, the charge temperature280, the VE284, the intake port pressure288, the cylinder volume, and the ideal gas constant. The measured APC module264may determine the measured APC260when not in the steady-state condition, for example, using one or more functions and/or mappings that relate the VE correction, the charge temperature280, the VE284, the intake port pressure288, the cylinder volume, and the ideal (or universal) gas constant to the measured APC260.

For example, when not in the steady-state condition, the measured APC module264may determine the measured APC260using the equation:

APCM=VECorr*ηe*Vcyl*PintR*T,(10)
where APCMis the measured APC260, VECorr is the VE correction, R is the ideal gas constant, T is the charge temperature280, ηeis the VE284, Vcylis the cylinder volume, and Pintis the intake port pressure288.

A VE module292(seeFIG. 2) determines the VE284based on the intake port pressure288, an exhaust port pressure296, an intake phase angle300, an exhaust phase angle304, an engine speed308, and a cylinder activation/deactivation sequence used312. The VE module292may determine the VE284, for example, using one or more functions and/or mappings that relate the intake port pressure288, the exhaust port pressure296, the intake phase angle300, the exhaust phase angle304, the engine speed308, and the cylinder activation/deactivation sequence used312to the VE284.

For example, the VE module292may determine the VE284using the relationship:

VE=f⁡(PintPExh,RPM,θint,θExh,SequenceUsed),(11)
where VE is the VE284, PIntis the intake port pressure288, PExhis the exhaust port pressure296, κIntis the intake phase angle300, θExhis the exhaust phase angle304, RPM is the engine speed308, and SequenceUsed is the cylinder activation/deactivation sequence used312. As described above, the intake port pressure288corresponds to a predicted pressure within the intake port of the present cylinder at approximately intake valve closing. The exhaust port pressure296corresponds to pressure at an exhaust port of the present cylinder at approximately exhaust valve closing. The exhaust port pressure296may be determined, for example, based on an APC and the engine speed308. An engine speed module316may determine the engine speed308based on a crankshaft position320measured using the crankshaft position sensor180. The intake phase angle300may refer to the intake cam phaser position or intake valve phasing relative to crankshaft position. The exhaust phase angle304may refer to the exhaust cam phaser position or exhaust valve phasing relative to crankshaft position.

A sequence monitoring module322monitors the desired cylinder activation/deactivation sequence248and sets the cylinder activation/deactivation sequence used312based on the desired cylinder activation/deactivation sequence248. When a cylinder is activated or deactivated according to the desired cylinder activation/deactivation sequence248, an oldest entry of the cylinder activation/deactivation sequence used312is removed, and the cylinder activation/deactivation sequence used312is updated to reflect whether the cylinder was activated or deactivated. This process is repeated for each cylinder in the firing order.

The cylinder activation/deactivation sequence used312therefore indicates the pattern or sequence of how the last Q cylinders in the firing order were activated and/or deactivated. Q is an integer greater than one and may, for example, be equal to the number of cylinders addressed over a predetermined number of crankshaft rotations, such as two crankshaft rotations (one engine cycle), three crankshaft rotations, four crankshaft rotations, or more crankshaft rotations. Q may therefore be greater than 1 and less than the total number of cylinders of the engine102, or Q may be greater than or equal to the total number of cylinders of the engine102. The pattern may be stored, for example, a buffer (e.g., ring, circular, first-in first-out), a register, an array, a vector, or in another suitable form. A zero may indicate that the corresponding cylinder was activated, and a one may indicate that the corresponding cylinder was deactivated, or vice versa. For example only, the following may be an example of the cylinder activation/deactivation sequence used312where the last Q cylinders were alternately activated and deactivated and Q is equal to 8.
[0 1 0 1 0 1 0 1]  (12)

The VE module292may alternatively determine the VE284using the equation:

A first APC prediction module324(seeFIG. 3) generates the first predicted APC256. The first APC prediction module324determines the first predicted APC256based on the MAF based APC268, the intake port pressure288, the cylinder activation/deactivation sequence used312, a corrected APC328, a throttle opening332, and a location of the next (activated) cylinder in the firing order. The first APC prediction module324may determine the first predicted APC256, for example, using one or more functions and/or mappings that relate the MAF based APC268, the intake port pressure288, the cylinder activation/deactivation sequence used312, the corrected APC328, the throttle opening332, and the location of the next cylinder to the first predicted APC256.

For example, the first APC prediction module324may determine the first predicted APC256using the equation:
APC1=α0*APCCorr(k)+Σi=12αiAPCMAF(k−i)+Σj=02βjPInt(k−j)+Σl=02γlThrottle(k−l)+Σm=02δm*f(SequenceUsed,Cyl #),  (17)
where APC1 is the first predicted APC256, APCCorr is the corrected APC328, APCMAFis the MAF based APC268, Pintis the intake port pressure288, Throttle is the throttle opening332, SequenceUsed is the cylinder activation/deactivation sequence used312, Cyl# is the location of the next cylinder in the firing order, and α, β, γ, and δ are coefficients. α, β, γ, and δ are predetermined values. The first APC prediction module324may determine α, β, γ, and δ, for example, based on the engine speed308and/or a pressure within the intake manifold110(e.g., the MAP276). The throttle opening332corresponds to a present opening (e.g., position, area, etc.) of the throttle valve112. As such, the first predicted APC256is determined based on the MAF based APC268for the last two activated cylinders, the intake port pressure288for the last three activated cylinders, the throttle opening332for the last two cylinders, the location of the next cylinder in the firing order, and the cylinder activation/deactivation sequence used312over the last predetermined period. While use of 3 samples in the summations is described, a greater number of samples may be used in various implementations.

A delay module336receives the first predicted APC256and outputs a previous value of the first predicted APC256as a previous APC340. The previous APC340may therefore correspond to the first predicted APC256for the last (activated) cylinder in the firing order. For example only, the delay module336may include a one-unit, first-in-first-out (FIFO) buffer.

An error module344determines an APC error348based on the previous APC340and the measured APC260. The error module344may, for example, set the APC error348equal to or based on a difference between the previous APC340and the measured APC260.

An APC correction module352generates the corrected APC328. The APC correction module352determines the corrected APC328based on the APC error348and the previous APC340. The APC correction module352may determine the corrected APC328, for example, using one or more functions and/or mappings that relate the APC error348and the previous APC340to the corrected APC328. For example only, the APC correction module352may determine the corrected APC328using the equation:
APCCorr=APCPrev+K*(APCM−APCPrev),  (18)
where APCCorr is the corrected APC328, K is a coefficient, APCMis the measured APC260, and APCPrevis the previous APC340. K may be a predetermined value or may be set, for example, using Kalman filtering theory, state-observer theory, or in another suitable manner.

A second APC prediction module356generates the second predicted APC258. The second APC prediction module356determines the second predicted APC258based on the first predicted APC256, the MAF based APC268, the intake port pressure288, the cylinder activation/deactivation sequence used312, the throttle opening332, and the location of the next (activated) cylinder following the next cylinder in the firing order. The second APC prediction module356may determine the second predicted APC258, for example, using one or more functions and/or mappings that relate the first predicted APC256, the MAF based APC268, the intake port pressure288, the cylinder activation/deactivation sequence used312, the throttle opening332, and the location of the activated cylinder following the next cylinder in the firing order.

For example, the second APC prediction module356may determine the second predicted APC258using the equation:
APC2=α0*APC1(k)+Σi=12αiAPCMAF(k−i)+Σj=02βjPInt(k−j)+Σl=02γlThrottle(k−l)+Σm=02δm*f(SequenceUsed,Cyl #),  (19)
where APC2 is the second predicted APC258, APC1 is the first predicted APC256, APCMAFis the MAF based APC268, PIntis the intake port pressure288, Throttle is the throttle opening332, SequenceUsed is the cylinder activation/deactivation sequence used312, Cyl# is the location of the activated cylinder following the next cylinder, and α, β, γ, and δ are the coefficients. While use of 3 samples in the summations is described, a greater number of samples may be used in various implementations.

The fuel control module232may regulate fueling based on the second predicted APC258. For example, the fuel control module232may control fueling to the next (activated) cylinder following the next (activated) cylinder in the firing order based on achieving a predetermined air/fuel ratio (e.g., a stoichiometric air/fuel ratio) with the second predicted APC258.

A torque estimation module360generates an estimated torque output of the engine102based on the first predicted APC256. The estimated torque output of the engine102may be referred to as engine torque364. One or more engine operating parameters may be regulated based on the engine torque364. For example, the boost control module240, the throttle control module216, and/or the phaser control module237may generate the desired boost242, the desired throttle opening220, and/or the desired intake and/or exhaust cam phaser angles238and239, respectively, based on the engine torque364. Engine load and/or one or more other parameters may be determined based on the first predicted APC256. Spark timing and/or one or more other engine operating parameters may be regulated based on the first predicted APC256.

Referring now toFIG. 4, a flowchart depicting an example method of generating the first and second predicted APCs256and258is presented. Control may begin with404where control receives the data for determining the first and second predicted APCs256and258. At408, the VE module292determines the VE284. The VE module292determines the VE284based on the intake port pressure288, the exhaust port pressure296, the intake phase angle300, the exhaust phase angle304, the engine speed308, and the cylinder activation/deactivation sequence used312. For example, the VE module292may determine the VE284using (11) or (13), as described above.

At412, control determines whether the steady-state condition is present. If false, control continues with416; if true, control continues with420. The steady-state condition may be present, for example, when a change in pressure within the intake manifold110(e.g., the MAP276measured using the MAP sensor184) over a predetermined period is less than a predetermined amount.

The measured APC module264determines the measured APC260at416based on the VE correction, the charge temperature280, the VE284, the intake port pressure288, the cylinder volume, and the ideal gas constant. For example, when not in the steady-state condition, the measured APC module264may determine the measured APC260using (10), as described above. Control continues with428, which is discussed further below.

At420, when in the steady-state condition, the measured APC module264updates the VE correction. The measured APC module264determines the VE correction based on the charge temperature280, the VE284, the intake port pressure288, the cylinder volume, and the ideal (or universal) gas constant, for example, using (9), as described above. Control continues with424.

The measured APC module264sets the measured APC260equal to the MAF based APC268at424. The measured APC module264may determine the MAF based APC268based on the MAF272measured using the MAF sensor186. For example only, the MAF based APC268may be set equal to or based on an integral of the MAF272over a predetermined period. Control continues with428.

At428, the error module344determines the APC error348. The error module344determines the APC error348based on a difference between the previous APC340and the measured APC260. The APC correction module352determines the corrected APC328at432. The APC correction module352determines the corrected APC328based on the APC error348and the previous APC340. For example, the APC correction module352may determine the corrected APC328using (18), as described above.

The first APC prediction module324determines the first predicted APC256at436. The first APC prediction module324determines the first predicted APC256based on the MAF based APC268, the intake port pressure288, the cylinder activation/deactivation sequence used312, the corrected APC328, the throttle opening332, and the location of the next cylinder in the firing order. For example, the first APC prediction module324may determine the first predicted APC256using (17), as described above. The delay module336stores the first predicted APC256and outputs the last value of the first predicted APC256as the previous APC340at440.

At444, the second APC prediction module356determines the second predicted APC258. The second APC prediction module356determines the second predicted APC258based on the MAF based APC268, the intake port pressure288, the cylinder activation/deactivation sequence used312, the first predicted APC256, the throttle opening332, and the location of the next cylinder following the next cylinder in the firing order. For example, the second APC prediction module356may determine the second predicted APC258using (19), as described above. At448, one or more engine operating parameters are controlled based on the first predicted APC256and/or the second predicted APC258, and control may end. While control is shown and discussed as ending after448,FIG. 4may be illustrative of one control loop, and control loops may be executed at a predetermined rate.

The apparatuses and methods described herein may be partially or fully implemented by one or more computer programs executed by one or more processors. The computer programs include processor-executable instructions that are stored on at least one non-transitory tangible computer readable medium. The computer programs may also include and/or rely on stored data. Non-limiting examples of the non-transitory tangible computer readable medium include nonvolatile memory, volatile memory, magnetic storage, and optical storage.