DE102013217406B4 - Method of controlling an effective number of cylinders - Google Patents

Abstract

A cylinder control method comprising: selecting one of N predetermined cylinder activation/deactivation patterns based on a desired average number of activated cylinders (118) per sub-period of a predetermined period comprising P sub-periods, the one of the N predetermined cylinders - activation/deactivation pattern corresponding to Q activated cylinders (118) per sub-period, where Q is an integer between zero and a total number of cylinders (118) of an engine (102), inclusive such number, P is an integer greater than one and the desired average number of active cylinders (118) is an integer or non-integer between zero and the total number of cylinders (118) of the engine (102);an adjusted cylinder activation/deactivation pattern based on the one of the N predetermined ones cylinder activation/deactivation pattern is determined;a desired cylinder activation/deactivation u ng pattern (252) for the predetermined period of time during a first number of the P sub-periods using the one of the N predetermined cylinder activation/deactivation patterns and during a second number of the P sub-periods using the adjusted cylinder activation/deactivation pattern;that opening intake and exhaust valves of first ones of the cylinders (118) to be activated based on the desired cylinder activation/deactivation pattern (252); opening intake and exhaust valves of second ones of the cylinders (118), that are to be deactivated are deactivated based on the desired cylinder activation/deactivation pattern (252);delivering fuel to the first ones of the cylinders (118); and shutting off fuel supply to the second ones of the cylinders (118),wherein determining the adjusted cylinder activation/deactivation pattern comprises changing a deactivated cylinder (118) of the one of the N predetermined cylinder activation/deactivation patterns into an activated cylinder (118 ) is changed or that an activated cylinder (118) of the one of the N predetermined cylinder activation/deactivation patterns is changed to a deactivated cylinder (118), characterized in that the cylinder (118) changing to an activated cylinder (118) is changed is rotated between the deactivated cylinders (118), and the cylinder (118) being changed to a deactivated cylinder (118) is rotated between the activated cylinders (118).

Description

AREA

The present disclosure relates to systems and methods for controlling cylinder deactivation for an internal combustion engine.

BACKGROUND

Internal combustion engines combust an air and fuel mixture in cylinders to drive pistons, which produces drive torque. Air flow into the engine is regulated by a throttle. More specifically, the throttle adjusts throttle area, which increases or decreases airflow into the engine. As the throttle area increases, the airflow into the engine increases. A fuel control system adjusts the rate at which fuel is injected to provide a desired air/fuel mixture to the cylinders and/or achieve a desired torque output. Increasing the amount of air and fuel delivered to the cylinders increases the engine's torque output.

Under certain circumstances, one or more cylinders of an engine may be deactivated. Deactivation of a cylinder may include disabling opening and closing of intake valves of the cylinder and stopping fueling of the cylinder. For example, one or more cylinders may be deactivated to reduce fuel consumption if the engine is able to produce a requested amount of torque while the one or more cylinders are deactivated.

From the U.S. 2011/0 048 372 A1 a cylinder control method with the features according to the preamble of claim 1 is known.

An object of the invention is to provide a cylinder control method for reducing noise and vibration of an internal combustion engine when cylinders are deactivated and activated again.

SUMMARY

This object is achieved by a cylinder control method having the features of claim 1.

The cylinder control method includes: selecting one of N predetermined cylinder activation/deactivation patterns based on a desired average number of activated cylinders per sub-period of a predetermined time period comprising P sub-periods. The one of the N predetermined cylinder activation/deactivation patterns corresponds to Q activated cylinders per sub-period, where Q is an integer between zero and a total number of cylinders of an engine, inclusive, P is an integer greater than one and is the desired mean number of activated cylinders is an integer or non-integer between zero and the total number of cylinders of the engine. The cylinder control method further includes: determining an adjusted cylinder activation/deactivation pattern based on the one of the N predetermined cylinder activation/deactivation patterns; that a desired cylinder activation/deactivation pattern for the predetermined period of time during a first number of the P sub-periods using the one of the N predetermined cylinder activation/deactivation patterns and during a second number of the P sub-periods using the adjusted cylinder activation/deactivation pattern deactivation pattern is generated; enabling opening of intake and exhaust valves of first ones of the cylinders to be activated based on the desired cylinder activation/deactivation pattern; that opening of intake and exhaust valves of second ones of the cylinders to be deactivated is deactivated based on the desired cylinder activation/deactivation pattern; that fuel is supplied to the first of the cylinders; and that a fuel supply for the second of the cylinders is cut off.

Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.

character list

• 1 ein Funktionsblockdiagramm eines beispielhaften Motorsystems gemäß der vorliegenden Offenbarung ist;
• 2 ein Funktionsblockdiagramm eines Motorsteuermoduls gemäß der vorliegenden Offenbarung ist;
• 3 ein Funktionsblockdiagramm eines Zylindersteuermoduls gemäß der vorliegenden Offenbarung ist; und
• 4 ein Funktionsblockdiagramm eines Zylinder-Deaktivierungsverfahrens gemäß der vorliegenden Offenbarung ist.

The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

• 1 Figure 12 is a functional block diagram of an exemplary engine system according to the present disclosure;
• 2 12 is a functional block diagram of an engine control module according to the present disclosure;
• 3 12 is a functional block diagram of a cylinder control module according to the present disclosure; and
• 4 12 is a functional block diagram of a cylinder deactivation method according to the present disclosure.

DETAILED DESCRIPTION

One or more cylinders of a vehicle's engine may be deactivated and/or operated according to a selected deactivation pattern (i.e., according to a selected deactivation sequence). For example, the engine includes multiple possible deactivation patterns, and the vehicle determines which of the deactivation patterns will be implemented and selects a deactivation pattern accordingly. The engine's cylinders are selectively operated (i.e., fired or not fired) based on the deactivation pattern over one or more engine cycles. For example only, a control module of the vehicle determines the selected deactivation pattern based on a variety of factors including a desired Effective Cylinder Count (ECC), respective fuel economies associated with each of the deactivation patterns, and/or noise and vibration ( N&V) associated with, but not limited to, each of the deactivation patterns. Fuel economy and N&V are based, at least in part, on the sequence in which the cylinders are activated and deactivated (i.e., the deactivation pattern).

Each of a plurality of predetermined base patterns may correspond to an ECC that is an integer (e.g., 1, 2, 3,..., n, where n is the number of cylinders in the engine). A desired ECC corresponds to a desired engine output torque. More specifically, the desired ECC corresponds to a desired average number of activated cylinders over a predetermined time period (e.g., a predetermined number of crankshaft revolutions, engine cycles, or cylinder events) to achieve the desired engine output torque over the predetermined time period.

The predetermined time period includes a plurality of predetermined sub-time periods, each sub-time period corresponding to the length of the predetermined base patterns. A cylinder deactivation system according to the principles of the present disclosure uses combinations of two or more of the predetermined base time periods during the predetermined time period to achieve a non-integer ECC. For example, to achieve a desired ECC of 6.5 with an 8 cylinder engine, a first predetermined baseline pattern in which 6 of the 8 cylinders are activated (and 2 cylinders are deactivated) during some (e.g. half) of the predetermined sub-time periods per sub-period, and a second predetermined base pattern wherein 7 of the 8 cylinders are activated (and 1 cylinder is deactivated) may be used during the other (e.g. during the other half) of the predetermined sub-periods per sub-period. This allows an average of 6.5 active cylinders per sub-period to be achieved during the predetermined period.

Now on 1 Referring now, a functional block diagram of an example engine system 100 is presented. A vehicle's engine system 100 includes an engine 102 that combusts an air/fuel mixture to generate torque based on driver input from a driver input module 104 . Air is drawn into the engine 102 through an intake system 108 . The intake system 108 may include an intake manifold 110 and a throttle valve 112 . For example only, the throttle valve 112 may include a butterfly valve with a rotatable blade. An engine control module (ECM) 114 controls a throttle actuator module 116 and the throttle actuator module 116 regulates opening of the throttle valve 112 to control airflow into the intake manifold 110 .

Air from the intake manifold 110 is inducted into cylinders of the engine 102 . Although engine 102 includes multiple cylinders, a single representative cylinder 118 is shown for purposes of illustration. For example only, engine 102 may have 2, 3, 4, 5, 6, 8, 10, and/or 12 cylinders. The ECM 114 may instruct a cylinder actuator module 120 to selectively deactivate some of the cylinders under certain circumstances discussed below, which may improve fuel economy.

The engine 102 may operate using a four-stroke engine cycle. The four strokes described below are referred to as the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke. Two of the four strokes in cylinder 118 occur during each revolution of a crankshaft (not shown). Therefore, it takes two crankshaft revolutions for cylinder 118 to complete all four strokes.

During the intake stroke, air is admitted from the intake manifold 110 into the cylinder 118 through an intake valve 122 . The ECM 114 controls a fuel actuator module 124 that regulates fuel injection to achieve a desired air/fuel ratio. Fuel may be injected into the intake manifold 110 at a central location or at multiple locations, such as near the intake valve 122 of each of the cylinders will. 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 module 124 may stop injecting fuel into cylinders that are deactivated.

The injected fuel mixes with air and creates an air/fuel mixture in the cylinder 118. During the compression stroke, a piston (not shown) in the cylinder 118 compresses the air/fuel mixture. The engine 102 may be a compression ignition engine, in which case compression causes the air/fuel mixture to ignite. Alternatively, the engine 102 may be a spark-ignition engine, in which case a spark actuator module 126 activates a spark plug 128 in the cylinder 118 based on a signal from the ECM 114, which ignites the air/fuel mixture. Some types of engines, such as homogeneous charge compression ignition (HCCI) engines, can perform both compression ignition and spark ignition. The timing of the spark can be specified relative to the time when the piston is at its top position, referred to as top dead center (TDC).

The spark actuator module 126 may be controlled by a timing signal that specifies how far before or after TDC to generate the spark. Since piston position is directly related to crankshaft position, the operation of the spark actuator module 126 can be synchronized with crankshaft position. The spark actuator module 126 may stop providing spark to the deactivated cylinders or provide spark to the deactivated cylinders.

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

During the exhaust stroke, the piston begins to move back up from the BDC and expels the by-products of combustion through an exhaust valve 130 . The by-products of the combustion are exhausted from the vehicle via an exhaust system 134 .

Intake valve 122 may be controlled by an intake camshaft 140 while exhaust valve 130 may be controlled by an exhaust camshaft 142 . In various implementations, multiple intake camshafts (including intake camshaft 140) may control multiple intake valves (including intake valve 122) for cylinder 118 and/or intake valves (including intake valve 122) of multiple banks of cylinders (including cylinder 118). Similarly, multiple exhaust camshafts (including exhaust camshaft 142) may control multiple exhaust valves for cylinder 118 and/or exhaust valves (including exhaust valve 130) for multiple banks of cylinders (including cylinder 118).

The cylinder actuator module 120 may disable the cylinder 118 by disabling opening of the intake valve 122 and/or the exhaust valve 130 . The time at which the intake valve 122 is opened may be varied by an intake cam phaser 148 relative to piston TDC. The time at which the exhaust valve 130 is opened may be varied by an exhaust cam phaser 150 relative to piston TDC. A phaser actuator module 158 may control the intake cam phaser 148 and the exhaust cam phaser 150 based on signals from the ECM 114 . When implemented, variable valve lift (not shown) may also be controlled by the phaser actuator module 158 . In various other implementations, intake valve 122 and/or exhaust valve 130 may be controlled by actuators other than camshafts, such as electromechanical actuators, electrohydraulic actuators, and electromagnetic actuators, etc.

The engine system 100 may include a boost device that provides pressurized air to the intake manifold 110 . For example shows 1 a turbocharger having a turbine 160 - 1 driven by exhaust gases flowing through exhaust system 134 . The turbocharger also includes a compressor 160 - 2 that is driven by the turbine 160 - 1 and that compresses air that is directed into the throttle valve 112 . In various implementations, a crankshaft driven turbo compressor (not shown) may compress air from the throttle valve 112 and deliver the compressed air to the intake manifold 110 .

A wastegate 162 may allow exhaust gas to bypass the turbine 160-1, thereby reducing the boost pressure (the amount of intake air compression) of the turbocharger. The ECM 114 may control the turbocharger via a boost actuator module 164 . That Boost pressure actuator module 164 may modulate turbocharger boost pressure by controlling the position of wastegate 162 . In various implementations, multiple turbochargers may be controlled by the boost actuator module 164 . The turbocharger may have variable geometry that may be controlled by the boost actuator module 164 .

An intercooler (not shown) may dissipate some of the heat contained in the compressed air charge generated as the air is compressed. Although shown separately for purposes of illustration, the turbine 160-1 and compressor 160-2 may be mechanically linked and bring the intake air into close proximity with the hot exhaust gas. The compressed air charge may absorb heat from exhaust system 134 components.

The engine system 100 may include an exhaust gas recirculation (EGR) valve 170 that selectively recirculates exhaust gas back to the intake manifold 110 . The EGR valve 170 may be located upstream of the turbocharger's turbine 160-1. The EGR valve 170 can be controlled by an EGR actuator module 172 .

Crankshaft position can be measured using a crankshaft position sensor 180 . A temperature of engine coolant may be measured using an engine coolant temperature (ECT) sensor 182 . The ECT sensor 182 may be located within the engine 102 or other locations where coolant circulates, such as within a radiator (not shown).

A pressure in the intake manifold 110 may be measured using a manifold absolute pressure (MAP) sensor 184 . In various implementations, engine vacuum, which is the difference between ambient barometric pressure and the pressure within the intake manifold 110, may be measured. A mass air flow rate into the intake manifold 110 may be measured using a mass air flow (MAF) sensor 186 . In various implementations, the MAF sensor 186 may be disposed in a housing that also includes the throttle valve 112 .

Throttle valve 112 position may be measured using one or more throttle position sensors (TPS) 190 . A temperature of the air inducted into the engine 102 may be measured using an intake air temperature (IAT) sensor 192 . The engine system 100 may also include one or more other sensors 193 . The ECM 114 can use signals from the sensors to make control decisions for the engine system 100 .

The ECM 114 may be in communication with a transmission control module 194 to coordinate gear changes in a transmission (not shown). For example, the ECM 114 may reduce engine torque during a gear shift. The engine 102 outputs 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, control the transmission of torque between a transmission input shaft and the crankshaft. Torque is transmitted between the transmission input shaft and a transmission output shaft according to gears.

Torque is transferred between the transmission output shaft and wheels of the vehicle by means of one or more differentials, one or more drive shafts, and so on. The wheels that absorb the torque that is output through the transmission are called drive wheels. The wheels that are not receiving torque from the transmission are referred to as non-driven wheels.

The ECM 114 may be in communication with a hybrid control module 196 to coordinate operation of the engine 102 and one or more electric motors 198 . The electric motor 198 may also function as a generator and may be used to generate electrical energy for use by vehicle electrical systems and/or for storage in a battery. In various implementations, various functions of the ECM 114, transmission control module 194, and hybrid control module 196 may be integrated into one or more modules.

Any system that varies an engine parameter may be referred to as an engine actuator. Each engine actuator receives an actuator value. For example, the throttle actuator module 116 may be referred to as an engine actuator and the throttle area may be referred to as the actuator value. In the example of 1 For example, the throttle actuator module 116 achieves the throttle area by adjusting an angle of the throttle valve 112 blade.

The spark actuator module 126 may 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 module 120, fuel Actuator module 124, the phaser actuator module 158, the boost pressure actuator module 164 and the EGR actuator module 172 include. For these engine actuators, the actuator values may correspond to a cylinder activation/deactivation sequence, fueling rate, intake and exhaust cam phaser angle, boost pressure, and EGR valve opening area, respectively. The ECM 114 may generate the actuator values to cause the engine 102 to produce a desired engine output torque.

The ECM 114 and/or one or more other modules of the engine system 100 may implement the cylinder deactivation system of the present disclosure. For example, the ECM 114 selects a cylinder deactivation pattern from a plurality of base patterns based on one or more factors including engine speed, requested torque, a selected gear, air per cylinder (APC, e.g., an estimate or calculation of the mass of air in each cylinders), a residual exhaust gas per cylinder (RPC, e.g., a mass of residual exhaust gas in each cylinder), and corresponding cylinder identifiers (IDs), without being limited to these. The selected cylinder deactivation pattern includes zero or more deactivated cylinders. The ECM 114 selectively activates the deactivated one or more cylinders to achieve a desired ECC.

For example only, the base patterns may correspond to only integer ECCs, and the desired ECC may be between integers (e.g., at 6.5). Accordingly, the ECM 114 selectively activates one of the deactivated cylinders in a base pattern corresponding to an ECC of 6 to achieve the desired ECC of 6.5. For example, in a sequence of four iterations of the base pattern, the ECM 114 activates one of the deactivated cylinders in two of the four iterations. Thus, in two of the iterations, six cylinders are activated and in the other two of the iterations, seven cylinders are activated, resulting in an ECC of 6.5. On the two iterations where one of the deactivated cylinders is activated, the ECM 114 may activate the same cylinder, or it may alternate between activating a select one of the two deactivated cylinders. For example, the ECM 114 may activate one of the two deactivated cylinders in one iteration and activate the other of the two deactivated cylinders in another iteration. Or, the ECM 114 may activate one of the two deactivated cylinders in two of the four iterations in a first period and activate the other of the two deactivated cylinders in a second period. Accordingly, the deactivated cylinder that is selectively activated in selected iterations of the basic pattern is rotated between the deactivated cylinders.

For example only, the ECM 114 determines how often a deactivated cylinder should be activated (i.e., fired) during operation of the base pattern (i.e., a firing frequency) for ECCt < n according to [ECCt - ECC'] / {(ECC' + 1) - ECC'} where ECCt corresponds to a target ECC (i.e., a desired ECC), ECC' corresponds to a largest integer ECC that is less than or equal to ECCt, and n corresponds to a total number of cylinders. Accordingly, when ECCt equals 6.5 and ECC equals 6, the firing frequency equals 0.5 and therefore one of the deactivated cylinders is activated during half of the repetitions of the basic pattern. When ECCt=ECC', the ECM 114 operates the cylinders according to the appropriate base pattern. When ECCt=ECC'=n, the ECM 114 activates all cylinders. The deactivated cylinder being activated can be rotated to minimize N&V and/or to prevent any deactivated cylinder from being deactivated for an undesired period of time. In some implementations, one or more deactivated cylinders in a base pattern may be "masked" to prevent those cylinders from being activated in rotation. For example, one or more of the deactivated cylinders can be masked to minimize N&V. Further, when changing values of the ECC' (i.e., when changing base patterns), the ECM 114 may remain at a current base pattern until a deactivated cylinder corresponding to an activated cylinder in a next base pattern is fired. The fired deactivated cylinder corresponds to the first fired cylinder in the next base pattern.

In other implementations, ECC' corresponds to a smallest integer ECC greater than or equal to ECCt, and one or more activated cylinders are deactivated in selected repeats of the base pattern. In other words, activated cylinders are deactivated to decrease the ECC of the base pattern, rather than deactivated cylinders being activated to increase the ECC of a base pattern. For example, if ECCt equals 6.5 and ECC' equals 7, then the deactivation frequency of one of the activated cylinders is equal to [ECC' - ECCt] / {(ECC' - (ECC' - 1)} or 0.5 of the activated cylinders is deactivated during half of the repetitions of the basic pattern. This equation gives a similar but opposite result to the equation given above. However, an equation could be used and the decision made based on whether ECC' is greater than or less than ECCt whether one or more activated cylinders should be deactivated or one or more deactivated cylinders should be activated. In still other implementations, the ECM 114 alternates between two or more base patterns to achieve the desired ECC. For example, if the desired ECC is equal to 6.5, the ECM 114 may operate according to a base pattern corresponding to an ECC of 6 for half a given period of time and according to a base pattern corresponding to an ECC of 7 for the other half of the given period of time is equivalent to.

Now on 2 Referring now, a functional block diagram of an example engine control module (ECM) 200 is presented. A torque request module 204 may determine a torque request 208 based on one or more driver inputs 212, such as based on an accelerator pedal position, a brake pedal position, a cruise control input, and/or based on one or more other suitable driver inputs. The torque request module 204 may additionally or alternatively determine the torque request 208 based on one or more other torque requests, such as based on torque requests generated by the ECM 200 and/or based on torque requests received from other modules of the vehicle, such as such as the transmission control module 194, the hybrid control module 196, a chassis control module, etc.

One or more engine actuators may be controlled based on the torque request 208 and/or one or more other torque requests. For example, the throttle control module 216 may determine a desired throttle opening 220 based on the torque request 208 . The throttle actuator module 116 may adjust the opening of the throttle valve 112 based on the desired throttle opening 220 . A spark control module 224 may determine a desired spark timing 228 based on the torque request 208 . The spark actuator module 126 may generate a spark based on the desired spark timing 228 . A fuel control module 232 may determine one or more desired fueling parameters 236 based on the torque request 208 . For example, the desired fueling parameters 236 may include a fuel injection amount, a number of fuel injections to inject the amount, and a timing for each of the injections. The fuel actuator module 124 may inject fuel based on the desired fueling parameters 236 . A boost control module 240 may determine a desired boost 244 based on the torque request 208 . The boost pressure actuator module 164 may control a boost pressure output by the boost device(s) based on the desired boost pressure 244 .

Additionally, a cylinder control module 248 generates a desired cylinder activation/deactivation pattern 252 (e.g., from a plurality of base patterns) based on the torque request 208. The cylinder actuator module 120 deactivates the intake and exhaust valves of the cylinders to be deactivated according to the desired cylinder activation / deactivation pattern 252 and activates the intake and exhaust valves of the cylinders to be activated according to the desired cylinder activation/deactivation pattern 252.

The cylinder control module 248 may also select the desired cylinder activation/deactivation pattern 252 based in part on the APC, RPC, engine speed, selected gear, slip, and/or vehicle speed, by way of example only. For example, an APC module 256 determines APC based on MAP, MAF, throttle, and/or engine speed, an RPC module 260 determines RPC based on an intake angle and an exhaust angle, EGR valve position, MAP, and/or or engine speed, and an engine speed module 264 determines engine speed based on a crankshaft position. The cylinder control module 248 selectively activates deactivated cylinders in the selected base pattern (and/or selectively deactivates activated cylinders in the selected base pattern) to achieve a desired ECC between integer ECCs.

Fueling is stopped (no fueling) for cylinders that are to be deactivated according to the desired cylinder activation/deactivation pattern 252, and fuel is supplied to the cylinders that are to be activated according to the desired cylinder activation/deactivation pattern 252 delivered. Spark is provided to the cylinders to be activated according to the desired cylinder activation/deactivation pattern 252 . Spark may be delivered to or stopped for the cylinders to be deactivated according to the desired cylinder activation/deactivation pattern 252 . Cylinder deactivation differs from fuel cut (e.g., deceleration fuel cut) in that the intake and exhaust valves of cylinders to which vehicle supply is stopped during fuel cut continue to open and close during the fuel cutoff.

Now on 3 Referring now, an example implementation of the cylinder control module 248 is shown. A number of N predetermined cylinder activation/deactivation patterns (base patterns, by way of example only) are stored in a pattern database 304 . N is an integer greater than or equal to 2 and may be, for example, 3, 4, 5, 6, 7, 8, 9, 10, or any other suitable value. Each of the N predetermined cylinder activation/deactivation patterns includes an indicator for each of the next M events of a predetermined cylinder firing order. M is an integer that can be less than, equal to, or greater than the total number of cylinders of engine 102 . For example only, M may be 20, 40, 60, 80, a multiple of the total number of cylinders of the engine, or any other suitable number. M may be calibratable and set based on, for example, engine speed, torque request, and/or the total number of cylinders of the engine 102 .

Each of the M indicators indicates whether the corresponding cylinder should be activated or deactivated in the predetermined firing order. For example only, the N predetermined cylinder activation/deactivation patterns may each comprise a data string comprising M (a number of) zeros and/or ones. A zero can indicate that the corresponding cylinder should be activated and a one can indicate that the corresponding cylinder should be deactivated, or vice versa.

A pattern control module 308 selects one of the N predetermined cylinder activation/deactivation patterns and sets the desired cylinder activation/deactivation pattern 252 to the selected one of the N predetermined cylinder activation/deactivation patterns. The cylinders of the engine 102 are activated or deactivated according to the desired cylinder activation/deactivation pattern 252 in the predetermined firing order. The desired cylinder activation/deactivation pattern 252 may be repeated until another one of the N predetermined cylinder activation/deactivation patterns is selected.

The pattern control module 308 includes a pattern determination module 312 and a pattern modification module 316. The pattern determination module 312 communicates with the pattern database 304 to select a cylinder activation/deactivation pattern based in part on the factors involved 2 and which include ECCt (which may be determined based on the torque request and/or based on other factors).

For example, the pattern determination module 312 may select one of the N predetermined cylinder activation/deactivation patterns that has a number of activated cylinders that corresponds to a nearest integer less than ECCt (or a nearest integer greater than ECCt) . The pattern determination module 312 may select one of the N predetermined cylinder activation/deactivation patterns based on a ranking of the N predetermined cylinder activation/deactivation patterns. For example only, the N predetermined cylinder activation/deactivation patterns may be ranked as in the preliminary US Patent Application No. 61/693057 filed August 24, 2012, which is incorporated herein in its entirety.

The pattern modification module 316 receives the selected one of the N predetermined cylinder activation/deactivation patterns from the pattern determination module 312 and dynamically modifies the desired cylinder activation/deactivation pattern 252, as described above with reference to FIG 1 and 2 is described. For example, the pattern modification module 316 receives the selected cylinder activation/deactivation pattern having a number of cylinders firing that corresponds to ECC' and modifies the selected cylinder activation/deactivation pattern based on ECCt to selectively include one or more of the deactivated cylinders to activate.

For example only, the pattern modification module 316 modifies one or more iterations of the selected cylinder activation/deactivation pattern according to [ECCt - ECC'] / {(ECC' +1) -ECC'}. The desired cylinder activation/deactivation pattern 252 output from the pattern modification module 316 includes the modifications. In other words, the desired cylinder activation/deactivation pattern 252 corresponds to the selected deactivation pattern (e.g., a selected base pattern) for some iterations. In other iterations, the desired cylinder activation/deactivation pattern 252 includes one or more additional activated cylinders to achieve ECCt. If more than one cylinder is deactivated in the base pattern, the pattern modification module 316 also determines which deactivated cylinders to activate on each iteration.

Now on 4 Referring now, a cylinder deactivation method 400 begins at 404. At 408, the method 400 selects cylinder activation activation/deactivation pattern. At 412, method 400 determines whether the ECC of the selected cylinder activation/deactivation pattern (ie, ECC') is equivalent to ECCt. If so, method 400 continues at 416 . If no, method 400 continues at 420 . At 416, method 400 outputs the selected cylinder activation/deactivation pattern.

At 420, the method 400 determines which deactivated cylinder or cylinders to selectively activate in the selected cylinder activation/deactivation pattern, including how often to activate an activated cylinder (i.e., a firing frequency of the deactivated cylinder) and at which repetition of the deactivation pattern the deactivated cylinder should be activated. At 424, method 400 modifies the selected cylinder activation/deactivation pattern in selected iterations of the selected cylinder activation/deactivation pattern. At 428, method 400 controls cylinder deactivation/activation according to the selected cylinder activation/deactivation pattern. Method 400 ends at 432.

The foregoing description is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. For purposes of clarity, the same reference numbers will be used throughout the drawings to identify similar elements. As used herein, the phrase A, B and/or C should be construed to mean a logical (A or B or C) using a non-exclusive logical or. It is understood that one or more steps within a method may be performed in different orders (or simultaneously) without altering the principles of the present disclosure.

As used herein, the term module can refer to an application specific integrated circuit (ASIC); an electronic circuit; a circuit of the circuit logic; a field programmable gate array (FPGA); a processor (shared, dedicated, or group) that executes code; other suitable hardware components that provide the described functionality; or relate to, be part of, or comprise a combination of some or all of the foregoing, such as in a system on chip. The term module can include a memory (shared, dedicated, or group) that stores code to be executed by the processor.

The term code, as used above, may include software, firmware, and/or microcode and may refer to programs, routines, functions, classes, and/or objects. The term shared, as used above, means that some or all code can be executed by multiple modules using a single (shared) processor. In addition, some or all code of multiple modules can be stored by a single (shared) memory. The term group as used above means that some or all of the code of a single module can be executed using a group of processors. In addition, some or all code of a single module can be stored using a group of memories.

The devices and methods described herein may be implemented by one or more computer programs executed by one or more processors. The computer programs comprise processor-executable instructions stored on a non-transitory, accessible, computer-readable medium. The computer programs can also include stored data. Non-limiting examples of the non-transitory, accessible, computer-readable medium are non-transitory memory, magnetic memory, and optical memory.

Claims (8)

A cylinder control method comprising: based on a desired average number of activated cylinders (118) per sub-period of a predetermined period comprising P sub-periods, selecting one of N predetermined cylinder activation/deactivation patterns, the one of the N predetermined cylinders - activation/deactivation pattern corresponding to Q activated cylinders (118) per sub-period, where Q is an integer between zero and a total number of cylinders (118) of an engine (102), inclusive such number, P is an integer greater than one and the desired average number of active cylinders (118) an integer or non-integer between zero and the whole number of cylinders (118) of the engine (102); determining an adjusted cylinder activation/deactivation pattern based on the one of the N predetermined cylinder activation/deactivation patterns; a desired cylinder activation/deactivation pattern (252) for the predetermined time period during a first number of the P sub-periods using the one of the N predetermined cylinder activation/deactivation patterns and during a second number of the P sub-periods using the adjusted cylinder activation -/Deactivation pattern is generated; opening intake and exhaust valves of first ones of the cylinders (118) to be activated based on the desired cylinder activation/deactivation pattern (252); disabling opening of intake and exhaust valves of second ones of the cylinders (118) to be disabled based on the desired cylinder enable/disable pattern (252); fuel is supplied to the first of the cylinders (118); and shutting off fuel supply to the second ones of the cylinders (118), wherein determining the adjusted cylinder activation/deactivation pattern comprises converting a deactivated cylinder (118) of the one of the N predetermined cylinder activation/deactivation patterns into an activated cylinder ( 118) is changed or that an activated cylinder (118) of one of the N predetermined cylinder activation/deactivation patterns is changed into a deactivated cylinder (118), characterized in that the cylinder (118) which changes into an activated cylinder (118 ) is changed, is rotated between the deactivated cylinders (118) and the cylinder (118) which is changed to a deactivated cylinder (118) is rotated between the activated cylinders (118). cylinder control procedure claim 1 , wherein determining the adjusted cylinder activation/deactivation pattern comprises changing a deactivated cylinder (118) of the one of the N predetermined cylinder activation/deactivation patterns to an activated cylinder (118) if Q is less than the desired average number is. cylinder control procedure claim 1 wherein determining the adjusted cylinder activation/deactivation pattern comprises changing an activated cylinder (118) of the one of the N predetermined cylinder activation/deactivation patterns to a deactivated cylinder (118) if Q is greater than the desired average number is. cylinder control procedure claim 1 , further comprising determining the first and second numbers of P sub-periods based on Q and the desired mean number. cylinder control procedure claim 4 Further comprising determining the first and second numbers of P sub-periods based on a difference between Q and the desired average number of activated cylinders (118) per sub-period of the predetermined period. cylinder control procedure claim 1 , further comprising selecting the one of the N predetermined cylinder activation/deactivation patterns based on Q being a nearest integer to the desired average number that is greater than the desired average number. cylinder control procedure claim 1 , further comprising selecting the one of the N predetermined cylinder activation/deactivation patterns based on Q being a nearest integer to the desired average number that is less than the desired average number. cylinder control procedure claim 1 , further comprising: determining a second customized cylinder activation/deactivation pattern based on the one of the N predetermined cylinder activation/deactivation patterns, wherein the second customized cylinder activation/deactivation pattern differs from the customized cylinder activation/deactivation pattern deactivation pattern is different; and the desired cylinder activation/deactivation pattern (252) for the predetermined time period is further generated during a third number of the P sub-time periods using the second adjusted cylinder activation/deactivation pattern.

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