Method and system for partial cylinder deactivation

Abstract

The present application relates to methods and systems for partial cylinder deactivation and provides methods and systems for reducing pumping losses during partial deactivation. In one example, a method includes flowing a vacuum to a de-activated cylinder group to remove gases trapped therein while an active cylinder group continues to combust.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to German Patent Application No. 102017209323.4, filed on June 1, 2017. For all purposes, the entire contents of the foregoing reference application are incorporated herein by reference. Technical Field

[0003] This instruction manual generally relates to reducing pumping losses during partial cylinder deactivation. Background Technology

[0004] Internal combustion engines can be used as drive units for motor vehicles. Within the scope of this disclosure, internal combustion engines may include Otto cycle engines, but may also include diesel engines and hybrid internal combustion engines utilizing a mixed combustion process, as well as hybrid drive systems that include not only internal combustion engines but also electric motors, which may be connected to the internal combustion engine in terms of drive and receive power from the internal combustion engine, or additionally output power as an activatable auxiliary drive device.

[0005] In the development of internal combustion engines, reducing fuel consumption to improve efficiency is desirable. Fuel consumption (and therefore efficiency) can be problematic. This is due to the fundamental operating process of the Otto cycle engine. Load control can be achieved via a throttle baffle arranged in the intake system. By adjusting the throttle baffle, the pressure of the incoming air downstream of the throttle baffle can be regulated. The further the throttle baffle is closed, that is, the more the throttle baffle blocks the intake system, the greater the pressure loss of the incoming air through the throttle baffle, and the lower the pressure of the incoming air downstream of the throttle valve and upstream of the inlet to at least two cylinders (i.e., the combustion chamber). For a constant combustion chamber volume, the air mass (i.e., quantity) can be set in this way based on the pressure of the incoming air. Therefore, quantity control can be undesirable, especially in partial load operation, because low load requires high throttling and a large pressure drop in the intake system, resulting in increased charge exchange losses as the load decreases and the throttling increases.

[0006] One solution for dethrottling Otto cycle engines is, for example, the operation of an Otto cycle engine with direct injection. Direct fuel injection enables stratified combustion chamber charging. Directly injecting fuel into the combustion chamber allows for regulation within the Otto cycle engine to a certain extent. Mixture formation is achieved by injecting fuel directly into the cylinder or into the air within the cylinder, rather than by forming an external mixture where fuel is introduced into the intake air of the intake system. However, the fuel / air mixture may not be adequately mixed under all engine operating conditions.

[0007] Another approach to a de-throttling solution for Otto cycle engines includes the use of at least partially variable valve drives. In contrast to non-variable valve drives, in which both the lift and the control timing of the valves are non-variable, these parameters, which influence the combustion process and thus the fuel consumption, can be varied more or less via variable valve drives. If the closing time of the inlet valve and the inlet valve lift can be changed, then de- throttling is possible and thus loss-free load control is possible. Then, the mass of the mixture flowing into the combustion chamber during the intake process is not controlled via the throttle flap, but via the inlet valve lift and the opening duration of the inlet valve. Variable valve drives can be expensive and thus generally not suitable for mass production.

[0008] Another approach to a de-throttling solution for Otto cycle engines can include cylinder deactivation, that is, deactivation of individual cylinders in certain load ranges. In partial load operation, the efficiency of an Otto cycle engine can be improved, that is, increased, by partially deactivating at least one cylinder of a multi-cylinder internal combustion engine, which can increase the load on the other cylinders that remain in operation if the engine power remains constant, so that the throttle flap can be opened further to introduce a greater mass of air into the operating cylinders, thereby achieving de-throttling of the internal combustion engine as a whole. During partial deactivation, the permanently running, for example, non-deactivatable, cylinders are operated in a region of higher load at which the specific fuel consumption is lower. The load set of the operating cylinders shifts towards higher loads.

[0009] Operating, for example, combusting, cylinders during partial deactivation also exhibit an increased air / fuel mixture due to the greater mass of air or mixture provided and the higher exhaust gas recirculation rate permitted. Furthermore, the efficiency of the deactivated, for example, non-combusting, cylinders increases due to a reduction and / or elimination of heat losses caused by heat transfer between the combustion gases and the combustion chamber walls.

[0010] It will be appreciated that diesel engines can experience similar benefits to cylinder deactivation. More specifically, partial deactivation can at least partially prevent diesel fuel-air mixtures from becoming too lean in the presence of an amount-regulated reduction in load due to a reduction in the amount of fuel used.

[0011] However, the inventors herein have recognized potential problems with such systems. As one example, pumping losses can occur in deactivated cylinders, which can reduce the overall power output of the engine, and thus the overall fuel efficiency. In other words, deactivated cylinders continue to participate in charge exchange, in which the deactivated cylinders continue to compress intake air. As noted above, these pumping losses can be remedied via switchable valve drives, such as variable valve drives. However, these solutions are expensive and require complex electrical connections that are prone to degradation.

[0012] To reduce costs, it can be desirable for the switchable or adjustable valve drive arrangements to be arranged on the inlet side and on the outlet side, wherein the valve drive arrangements of the deactivated cylinders remain closed and thus no longer participate in the charge exchange during partial deactivation. In this way, it is also prevented that the relatively cool charge air guided through the deactivated cylinders reduces the enthalpy of the exhaust gas stream provided to the turbine and cools the deactivated cylinders rapidly.

[0013] Furthermore, in the case of supercharging of the internal combustion engine via exhaust-gas turbocharging, the switchable valve drive arrangements can cause further problems, since the turbine of the exhaust-gas turbocharger is configured for a certain exhaust-gas flow rate above a threshold value and thus also generally for a certain number of cylinders. If the valve drive arrangements of the deactivated cylinders are deactivated, the total mass flow through the cylinders of the internal combustion engine first decreases. The exhaust-gas mass flow guided through the turbine decreases and the turbine pressure ratio generally also decreases as a result. The decreased turbine pressure ratio has the effect that the charge pressure ratio likewise decreases, that is to say the charge pressure drops, and less charge air can be supplied to the cylinders that remain in operation.

[0014] It can be desirable to increase the charge pressure in order to supply more charge air to the cylinders that remain in operation, since the load on the other cylinders that remain in operation increases in the case of partial deactivation of at least one cylinder of the multi-cylinder internal combustion engine, so that a greater amount of charge air and a greater amount of fuel can be supplied to said cylinders. The drive power available at the compressor for generating a sufficiently high charge pressure depends on the exhaust-gas enthalpy of the hot exhaust gas, which can be determined from the exhaust-gas pressure and the exhaust-gas temperature and the exhaust-gas mass or the exhaust-gas flow.

[0015] By opening the throttle flap, the charge pressure can be increased in the load range associated with partial deactivation. This possibility can not exist in the case of a diesel engine. A small charge air flow can cause the compressor to operate beyond the surge limit.

[0016] The above-mentioned effects can lead to a restriction on the feasibility of partial deactivation, in particular on the engine speed range and the load range in which partial deactivation can be used. At low charge air flow rates, it can not be desirable to increase the charge pressure according to demand due to insufficient compressor power or turbine power.

[0017] For example, the charge pressure during partial deactivation (and thus the charge air flow rate supplied to the cylinders that remain in operation) can be increased by a small configuration of the turbine cross section and via simultaneous exhaust gas blowdown, whereby the load range associated with partial deactivation can also be expanded again. However, when all cylinders are in operation, the supercharging behavior can be insufficient, which can reduce the power output and / or the fuel economy.

[0018] Since the turbine is equipped with a variable turbine geometry, the charge air pressure (and thus the boost air flow rate supplied to the still running cylinders) can also be increased during partial deactivation, which allows an efficient turbine cross section adaptation to the current exhaust mass flow. However, the exhaust back pressure in the exhaust gas discharge system upstream of the turbine will increase at the same time, resulting in higher charge exchange losses in the still running cylinders. SUMMARY

[0019] In an internal combustion engine according to the present disclosure, the second cylinder group (e.g. the inner cylinders) is not equipped with a deactivatable valve drive on the inlet side or on the outlet side. Instead, the deactivated cylinders continue to participate in the charge exchange, that is to say, during partial deactivation, the valves oscillate. However, the internal combustion engine to which the present disclosure relates can comprise at least one shut-off element on the inlet side and on the outlet side to optionally prevent fresh air from being supplied to the deactivated cylinders and exhaust gas from being discharged from the deactivated cylinders. During partial deactivation, the pistons of the deactivated cylinders draw in gas via the at least one inlet opening and force gas out via the at least one outlet opening. However, the gas is enclosed, that is to say, trapped, between the shut-off element arranged on the inlet side and the shut-off element arranged on the outlet side. This can resolve the charge air losses that occur and / or are accepted in the above-described previous examples.

[0020] In one example, the above problems can be solved by an internal combustion engine comprising: at least one cylinder head having at least two cylinders, wherein each of the two cylinders has at least one inlet opening fluidly coupled to an intake line for supplying fresh air via an intake system, each cylinder has at least one outlet opening fluidly coupled to an exhaust line for discharging exhaust gas via an exhaust discharge system, the at least two cylinders form a first cylinder group and a second cylinder group, the first cylinder group comprises at least a first cylinder and the second cylinder group comprises at least a second cylinder different from the first cylinder, wherein the first cylinder is non-switchable and the second cylinder is switchable; an intake system comprising a primary closing element configured to regulate a flow of fresh air to each of the first cylinder group and the second cylinder group and a secondary closing element configured to regulate a flow of fresh air to only the second cylinder group, via the secondary closing element the supply of fresh air to the at least one cylinder of the second group can be stopped; a second cylinder group exhaust line equipped with at least one exhaust closing element configured to regulate a flow of exhaust gas from the second cylinder group exhaust line to the exhaust discharge system; and a negative pressure source fluidly coupled at least to the second cylinder group exhaust line, wherein a negative pressure line fluidly coupling the negative pressure source is connected to the second cylinder group exhaust line at a location between the exhaust closing element and the second cylinder. In this way, the gas of the deactivated cylinder that is enclosed or trapped between the at least one closing element of the intake system of the second group and the at least one closing element of the exhaust discharge system of the second group during partial deactivation is at least partially drawn out via the negative pressure line by suction, that is, evacuation or expulsion.

[0021] As one example, the gas located in the cylinder that is deactivated during partial deactivation exerts less resistance on the oscillating piston of the deactivated cylinder during intake, exhaust and compression. In this way, charge exchange losses of the second cylinder group during partial deactivation can be reduced and fuel economy can be increased. At least one negative pressure line of the internal combustion engine according to the present disclosure branches between the at least one closing element of the intake system of the second group and the at least one closing element of the exhaust discharge system of the second group and is connectable or connected to a negative pressure source, for example a vacuum pump. The closing elements associated with the lines are used to open and close the negative pressure line.

[0022] It should be understood that the above summary of the application is provided in simplified form as an introduction to a selection of the concepts further described in the detailed description. It is not meant to determine key or essential features of the claimed subject matter, the scope of which is defined solely by the claims appended hereto. Moreover, the claimed subject matter is not limited to implementations that solve any or all of the disadvantages mentioned above or those described in any part of this disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1A first embodiment of an internal combustion engine is shown.

[0024] Figure 2 A schematic view of a single cylinder of an internal combustion engine is shown.

[0025] Figure 3 A method for operating an internal combustion engine during partial deactivation is shown.

[0026] Figure 4 An engine operating sequence illustrating a method performed in connection with an internal combustion engine is shown. Figure 3 DETAILED DESCRIPTION

[0027] The following description relates to systems and methods for removing charge air from at least one deactivated cylinder of an engine. More particularly, the engine can include a first cylinder group and a second group, where each of the first and second cylinder groups includes at least one cylinder. The cylinders of the first and second cylinder groups can be operated differently such that at least one cylinder of the first group can be combusting and at least one cylinder of the second group can be deactivated. An intake throttle and an exhaust throttle can correspond to the at least one cylinder of the second group such that charge air can be trapped between the intake throttle and the exhaust throttle. A vacuum can be applied between the intake throttle and the exhaust throttle to remove charge air trapped therein to reduce pumping losses during a partial deactivation state of the engine. Figure 1 and Figure 2 An example of an engine is shown in Figure 3 A method for operating the first and second cylinder groups, along with a vacuum source and the intake throttle and exhaust throttle of the second group is shown in Figure 4 An engine operating sequence illustrating a method operated in connection with Figure 1 and Figure 2 An engine operating sequence illustrating a method operated in connection with Figure 3 the engine shown in

[0028] Figures 1-2 ​Example configurations showing relative positioning of various components. If shown directly contacting or coupling to one another, such elements can be referred to individually or collectively as directly contacting or directly coupled, respectively, in at least one example. Similarly, elements shown abutting or adjacent one another can be referred to individually or collectively as abutting or adjacent one another, respectively, in at least one example. As an example, components arranged in coplanar contact with one another can be referred to as coplanarly contacting. As another example, elements positioned apart from one another with only a space there-between and without other components can be referred to as such in at least one example. As yet another example, elements shown above / below one another on opposite sides of one another, or left / right of one another, can be referred to as such relative to one another. Further, as shown in the figures, in at least one example, the topmost element or point of an element can be referred to as the "top" of the component, and the bottommost element or point of an element can be referred to as the "bottom" of the component. As used herein, top / bottom, over / under, above / below can be relative to the vertical axis of the figure and used to describe the positioning of elements of the figure relative to one another. As such, in one example, an element shown above other elements is positioned vertically above the other elements. As yet another example, the shape of elements depicted within the figures can be referred to as having those shapes (e.g., such as circular, straight, planar, curved, rounded, angled, etc.). Moreover, in at least one example, elements shown intersecting one another can be referred to as intersecting elements or intersecting one another. Furthermore, in one example, an element shown within another element or shown outside of another element can be referred to as such. It will be appreciated that one or more components referred to as "substantially similar and / or identical" to one another differ from one another by manufacturing tolerances (e.g., within 1-5% deviation).

[0029] The internal combustion engine according to the present disclosure can comprise at least two cylinders or at least two groups, wherein in each case at least one cylinder corresponds to each of the groups. In this respect, an internal combustion engine having three cylinders (three cylinders configured in three groups, each comprising one cylinder) or an internal combustion engine having six cylinders (six cylinders configured in three groups, each comprising two cylinders) is likewise an internal combustion engine according to the present disclosure. Within the context of partial deactivation, the three cylinder groups can be activated or deactivated successively, whereby a double switching can also be realized. The partial deactivation is thereby further optimized. The cylinder groups can also comprise a different number of cylinders. In this respect, an internal combustion engine having three cylinders (three cylinders configured in two groups) is also an internal combustion engine according to the present disclosure.

[0030] In some embodiments according to the present disclosure of an internal combustion engine, the engine allows for optimizing the efficiency of the internal combustion engine in partial load operation, that is to say at low loads, wherein low loads T low Preferably, the total is less than the maximum load T max,na load of 65% or 50% or at least less than 30%.

[0031] In some embodiments, additionally or alternatively, the intake lines of the at least one cylinder of the second group are merged with the formation of an inlet manifold to form a total intake line, and the inlet manifold of the second group, the second inlet manifold, is equipped with at least one shut-off element, which can regulate the supply of fresh air to the at least one cylinder of the second group during partial deactivation of the internal combustion engine.

[0032] The merging of the intake lines of the second cylinder group to form a total intake line shortens the length of the intake line as a whole and significantly reduces the volume of the associated intake system. Furthermore, the packaging constraints of the intake system can be reduced and a compact design of the internal combustion engine is achieved.

[0033] In an internal combustion engine in which the second group comprises only one cylinder, the merging of the intake lines with the formation of an inlet manifold to form a total intake line can be omitted if the deactivatable cylinder has only one inlet opening. The single intake line of the deactivatable cylinder then forms the total intake line and the inlet manifold of the second group.

[0034] In this case, embodiments of the internal combustion engine are advantageous in which the shut-off element is arranged in the total intake line of the second inlet manifold.

[0035] In the present case, the shut-off element is arranged in the total intake line of the second inlet manifold. In this embodiment, a single shut-off element is sufficient to stop the supply of fresh air to the deactivated cylinder.

[0036] The shut-off element can also be provided in each intake line of the deactivatable cylinder, although this increases the number of shut-off elements and can increase the manufacturing costs and increase the packaging constraints.

[0037] In this case, embodiments of the internal combustion engine can comprise a negative pressure line and / or a vacuum, which can be connected at least to a negative pressure source and in which the shut-off element is arranged, between the shut-off element in the total intake line of the second inlet manifold and the at least one cylinder of the second group.

[0038] In the present case, the negative pressure line branches off from the intake system on the inlet side with respect to the direction of the intake air flow, for example from the total intake line of the second inlet manifold, in particular from downstream of the shut-off element arranged in the second total intake line, that is to say from between the shut-off element in the second total intake line and the at least one cylinder of the second group.

[0039] Some embodiments of the internal combustion engine can comprise a situation in which the exhaust line of the at least one cylinder of the second group is merged with the formation of the outlet manifold to form a total exhaust line, and the outlet manifold of the second group, as a second outlet manifold, is equipped with at least one shut-off element via which the exhaust gas emission from the at least one cylinder of the second group can be adjusted during partial deactivation of the internal combustion engine.

[0040] The situation mentioned in connection with the merging of the intake lines applies analogously. That is, the exhaust lines can be merged analogously to the intake lines as described above. The length of the entire exhaust line can be shortened, and the volume of the associated exhaust gas discharge system can be reduced. Furthermore, the structural space of the exhaust gas system is reduced, and a compact design of the internal combustion engine is achieved.

[0041] In the internal combustion engine in which the second group comprises only one cylinder, if the deactivatable cylinder has only one outlet opening, the merging of the exhaust line with the formation of the outlet manifold to form a total exhaust line can be omitted. The single exhaust line of the deactivatable cylinder then forms the total exhaust line and the outlet manifold of the second group.

[0042] In this case, embodiments of the internal combustion engine can comprise a shut-off element arranged in the total exhaust line of the second outlet manifold. In the present case, the shut-off element is arranged in the total exhaust line of the second outlet manifold. In this embodiment, a single shut-off element can be sufficient to adjust the exhaust gas emission from the deactivated cylinder.

[0043] A shut-off element can also be provided in each exhaust line of the deactivatable cylinder, while if the deactivatable cylinder has more than one outlet opening and / or the second group comprises more than one deactivatable cylinder, this increases the number of shut-off elements required, which can increase the degree of control and / or metering of the exhaust gas emitted from the deactivatable cylinder.

[0044] In this case, embodiments of the internal combustion engine can comprise a negative pressure line which is at least connectable to a negative pressure source and in which a shut-off element is arranged, the negative pressure line branching between the shut-off element in the total exhaust line of the second outlet manifold and the at least one cylinder of the second group.

[0045] In the present case, the negative pressure line branches on the outlet side from the exhaust gas discharge system, for example from the total exhaust line of the second outlet manifold, in particular from upstream of the shut-off element arranged in the second total exhaust line, that is to say between the shut-off element in the second total exhaust line and the at least one cylinder of the second group.

[0046] Embodiments of the internal combustion engine can comprise a situation in which the at least one inlet-side shut-off element and / or the at least one outlet-side shut-off element is a valve.

[0047] Embodiments of the internal combustion engine can comprise wherein at least one inlet-side closing element and / or at least one outlet-side closing element is a pivotable shutter.

[0048] Embodiments of the internal combustion engine are advantageous wherein at least one closing element is continuously adjustable. If the cylinder is not deactivated but in fired operation, embodiments of closing elements as continuously adjustable closing elements allow for a controlled dosing of the fresh air flow rate being introduced into the second group of cylinders. The metering of the fresh air flow rate can be done in a way specific to the operating point, in particular with respect to the lowest possible charge exchange losses. The control of the closing elements can take into account the load T, the engine speed n, the coolant temperature in case of a liquid-cooled internal combustion engine, the oil temperature and / or similar factors.

[0049] However, embodiments of the internal combustion engine can comprise wherein at least one closing element is switchable in at least two stages, that is to say in a multi-stage manner if appropriate.

[0050] The closing elements can be electrically, hydraulically, pneumatically, mechanically or magnetically controllable via a signal sent by an engine controller. The controller can comprise instructions stored on a non-transitory memory of the controller that, when executed, enable the controller to adjust the closing elements.

[0051] In some embodiments, the internal combustion engine can comprise a supercharging arrangement. Supercharging can increase the power used to compress charge air for the engine combustion process, whereby a greater charge air mass can be fed to each cylinder in each working cycle. In this way, the fuel mass and thus the mean pressure can be increased.

[0052] Supercharging can increase the power of the internal combustion engine while keeping the swept volume constant, or reduce the swept volume while keeping the same power. In all cases, supercharging can result in an increase in volumetric power output and a more convenient power-to-weight ratio. If the swept volume is reduced, the load set can be shifted towards higher loads at which the specific fuel consumption is lower, given the same vehicle boundary conditions. Supercharging of the internal combustion engine thus helps to minimize the fuel consumption, that is to say to increase the efficiency of the internal combustion engine.

[0053] In some embodiments, a transmission configuration coupled to the engine can provide downshifting, whereby a lower specific fuel consumption is likewise achieved. In the case of downshifting, the fact is used that the specific fuel consumption at low engine speeds is generally lower, in particular in the presence of relatively high loads.

[0054] The supercharged internal combustion engine can comprise a charge air cooling arrangement configured to cool charge air before entering the at least two cylinders. In this way, the density of the supplied charge air is further increased. In this way, the cooling also contributes to the compression and the improvement of the charge of the combustion chamber, that is to say, the volumetric efficiency is increased. The charge air cooler can be equipped with a bypass line in order to be able to bypass the charge air cooler when required, for example during cold start.

[0055] For supercharging, an exhaust gas turbocharger can be used, wherein the compressor and the turbine are arranged on the same shaft. The hot exhaust gas stream is fed to the turbine and expanded in the turbine by releasing energy, whereby the shaft is rotated. The energy supplied to the shaft by the exhaust gas stream is used to drive the compressor, which is also arranged on the shaft. The compressor delivers and compresses the charge air supplied to it, whereby the supercharging of the at least one cylinder is achieved.

[0056] Therefore, embodiments of the internal combustion engine can comprise the case in which at least one exhaust gas turbocharger is provided, which comprises a turbine arranged in the exhaust gas discharge system and a compressor arranged in the intake system.

[0057] A supercharger that can be driven via an auxiliary drive can differ from an exhaust gas turbocharger in that the exhaust gas energy of the hot exhaust gas is utilized by the exhaust gas turbocharger, while the supercharger draws the energy required for driving the supercharger directly or indirectly from the internal combustion engine and thus adversely affects the efficiency, that is to say, reduces the efficiency, at least in the case where the driving energy does not originate from an energy recovery source.

[0058] If the supercharger is not an electrically, that is to say, electrically, driveable supercharger, a mechanical or kinematic connection for power transmission can be used between the supercharger and the internal combustion engine.

[0059] The advantage of the supercharger over the exhaust gas turbocharger is that the supercharger can generate and make available the desired charge pressure during a wide range of operating conditions, in particular independently of the operating state of the internal combustion engine, in particular independently of the current rotational speed of the crankshaft. This applies in particular to a supercharger that can be electrically driven via an electric machine.

[0060] In the previous examples, difficulties are encountered in particular when achieving power increase in all engine speed ranges via exhaust turbocharging. A relatively severe torque dip is observed below a certain engine speed. Said torque dip is understandable when considering that the charge air pressure ratio depends on the turbine pressure ratio. If the engine speed is lowered, this results in a smaller exhaust mass flow and thus in a lower turbine pressure ratio. Consequently, towards lower engine speeds, the charge air pressure ratio decreases as well. This corresponds to a torque dip.

[0061] The torque characteristics of a supercharged internal combustion engine can be improved by various measures, for example by means of a plurality of superchargers, exhaust turbochargers and / or mechanical superchargers arranged in parallel and / or in series.

[0062] In the case of an internal combustion engine according to the present disclosure, a first compressor can be provided in a first common intake line and a second compressor can be provided in a second common intake line, for example.

[0063] In the case of an internal combustion engine with four cylinders in inline arrangement, embodiments can comprise two outer cylinders and two inner cylinders forming a group in each case.

[0064] In the case of an internal combustion engine with three cylinders in inline arrangement, embodiments can comprise two outer cylinders and an inner cylinder forming a group in each case.

[0065] Embodiments of the internal combustion engine can comprise the case in which each cylinder has at least two inlet openings which are adjoined by an intake line for the supply of fresh air via the intake system.

[0066] During charge exchange, fresh mixture or fresh air is charged to the combustion chamber via the inlet openings. The valve drive device can open and close the inlet openings at the desired times, wherein a rapid opening of the maximum possible flow cross section is sought in order to keep the throttling losses low and to ensure the best possible charging of the combustion chamber. In this regard, it is advantageous if the cylinder is provided with two or more inlet openings.

[0067] Embodiments of the internal combustion engine can comprise the case in which each cylinder has at least two outlet openings which are adjoined by an exhaust line for the discharge of exhaust gases via the exhaust discharge system. The above-mentioned cases for the inlet openings apply analogously.

[0068] Embodiments of the internal combustion engine are advantageous in which a vacuum pump is used as a source of negative pressure. The vacuum pump can be an existing vacuum pump which already performs another function, or it can be a vacuum pump which is dedicated to the concept according to the present disclosure.

[0069] Embodiments of the internal combustion engine can comprise that the negative pressure region of the intake system acts as the negative pressure source.

[0070] Embodiments of the internal combustion engine can comprise that the cylinders operating in the intake phase of the first group act as the negative pressure source.

[0071] Embodiments of the internal combustion engine can comprise the case where each cylinder is equipped with a direct injection injector for the purpose of introducing fuel.

[0072] Here, embodiments are advantageous where each cylinder is equipped with an injection nozzle for the purpose of direct injection.

[0073] In the case of a direct injection internal combustion engine, for the purpose of partial deactivation, the fuel supply can be deactivated faster and more reliably than in the case of an internal combustion engine with intake pipe injection, where fuel residues in the intake pipe can lead to unwanted combustion in the deactivated cylinder.

[0074] However, embodiments of the internal combustion engine can comprise that an intake pipe injection element is provided for the purpose of supplying fuel.

[0075] Another embodiment of the present disclosure can comprise a method for operating an internal combustion engine of the type described above, which is implemented via the following method, wherein at least one switchable cylinder of the second group is switched in such a way that it depends on the load T of the internal combustion engine, i.e. the at least one switchable cylinder is deactivated below a predefinable load T down and activated above a predefinable load T up , it is provided that, during partial deactivation, the supply of fresh air to the at least one deactivated cylinder of the second group and the discharge of exhaust gases from the at least one deactivated cylinder of the second group is prevented by actuating the closure element, and by means of opening the associated closure element, the at least one negative pressure line is at least partially opened and connected to the negative pressure source for the purpose of reducing charge exchange losses during partial deactivation.

[0076] The limit loads T down and T up can be equal in size, but can also be different. The cylinders of the first cylinder group are permanently operating cylinders when the internal combustion engine is running. The second cylinder group is switched, i.e. the second group is activated and deactivated.

[0077] A method variant can comprise that at least one cylinder of the second group is deactivated when the current load is below a predefinable load T down and the current load remains below the predefinable load T down for a predefinable period of time At1.

[0078] If the load only briefly drops below the predefined load T down and then rises again, or fluctuates around the predefined value T down of the load without evidence of undershoot or the need for partial deactivation, the additional conditions introduced for the deactivation, that is to say, the partial deactivation, of the second group of cylinders are intended to prevent over-frequent activation and deactivation, in particular partial deactivation.

[0079] For these reasons, the method variant can comprise the case in which at least one cylinder of the second group is activated when the load exceeds the predefined load T up and the current load remains above said predefined load T up for a predefinable period of time At2.

[0080] The method variant can comprise deactivating the fuel supply to the at least one switchable cylinder during deactivation. This produces advantages in terms of fuel consumption and pollutant emissions, thus contributing to the goals pursued by partial deactivation, in particular reducing fuel consumption and increasing efficiency. In the case of an automatic ignition internal combustion engine, it can even be necessary to deactivate the fuel supply in order to reliably prevent ignition of the mixture located in the cylinder.

[0081] Additionally or alternatively, the method variant can comprise the case in which, after deactivating the at least one load-dependent switchable cylinder, the fuel supply of the at least one switchable cylinder is first deactivated before the closing element is actuated, and, after activating the at least one deactivated cylinder, the closing element is first actuated before the fuel supply of the at least one deactivated cylinder is activated.

[0082] The method can ensure that as long as the fuel supply is in the activated state, the deactivatable cylinder is supplied with fresh air and no fuel enters the cylinder when the fresh air supply is deactivated.

[0083] Embodiments of the method can comprise a predefinable load T down and / or T up which depends on the engine speed n of the internal combustion engine. There is then not only one specific load below or above which the switching takes place, regardless of the engine speed n. Rather, a method is followed which depends on the engine speed, and a region in the characteristic map is defined in which partial deactivation takes place.

[0084] Further operating parameters of the internal combustion engine, such as the engine temperature or coolant temperature after a cold start of the internal combustion engine, can essentially be used as criteria for partial deactivation.

[0085] Turning now to Figure 1which shows a first embodiment of an internal combustion engine 1. The internal combustion engine 1 is a four-cylinder in-line engine with direct injection, wherein the four cylinders 1, 2, 3, 4 are arranged along the longitudinal axis of the cylinder head 9, that is to say in a straight line, and in each case are equipped with an injector for injecting fuel, wherein the amount of fuel injected serves to set the air ratio λ (not shown).

[0086] The four cylinders 1, 2, 3, 4 are configured to form two groups of two cylinders each with the cylinders 1, 2, 3, 4, wherein the two outer cylinders 1, 4 form a first cylinder group and the two inner cylinders 2, 3 form a second cylinder group.

[0087] The inner cylinders 2, 3 of the second group can be configured as switchable cylinders 2, 3 which are deactivated during partial deactivation of the internal combustion engine. The outer cylinders 1, 4 of the first group are cylinders 1, 4 which are operated even during partial deactivation of the internal combustion engine, can be non-switchable.

[0088] Fresh air is supplied to the internal combustion engine 1 via an intake system 6. Each cylinder 1, 2, 3, 4 comprises an intake line for supplying fresh air via the intake system 6 and an exhaust line 7 for discharging exhaust gases via an exhaust discharge system 8. More specifically, the intake system 6A corresponds to the first cylinder group and the intake system 6B corresponds to the second cylinder group. Furthermore, the exhaust discharge 8A corresponds to the first cylinder group and the exhaust discharge 8B corresponds to the second cylinder group.

[0089] In other words, the intake system 6 comprises a main throttle 62 which is shaped to regulate the air flow rate through the main intake passage 5. The main intake passage 5 can be split into three branches and / or separated at the intersection 2, thereby forming a first cylinder group intake passage 5A and a second cylinder group intake passage 5B. The number of first cylinder group intake passages 5A can essentially equal the number of cylinders in the first cylinder group. In the example of Figure 1 In the example of

[0090] The second cylinder group intake passage 5B can be a single passage which is subsequently split and forms two second cylinder group intake passages 5C, wherein the number of second cylinder group intake passages 5C corresponds to the number of cylinders in the second cylinder group.

[0091] The intake lines 5a, 5b of the two cylinder groups merge in each case with the formation of the inlet manifold 6A, 6B of the particular group to form a total intake line 5. The intake manifold 6B of the second group, that is to say the second inlet manifold 6B, is equipped with a shut-off element 10a which is configured to stop the supply of fresh air to the cylinders 2, 3 of the second group during partial deactivation of the internal combustion engine. In the example of Figure 1In the embodiment shown in the figure, the inlet-side closing element 10a is arranged in the second cylinder group intake passage 5B upstream of the second intake manifold 6B and downstream of the cross-over point 2.

[0092] A negative pressure line 11a is arranged with a closing element 11a' and connectable to a negative pressure source 11 by opening the closing element 11a'. The negative pressure line 11a branches off from the second cylinder group intake passage 5B between the inlet-side closing element 10a and the second intake manifold 6B. Herein, the inlet-side closing element 10a can interchangeably be referred to as a secondary intake throttle 10a. The negative pressure source 11 can be one or more of a brake booster, an EGR valve or other similar device that can consume vacuum for operation.

[0093] Additionally or alternatively, the negative pressure source 11 can be a vacuum generating device, such as the main throttle 62. The vacuum generating device can be a vacuum device, such as a vacuum source. As is known to the person skilled in the art, an intake throttle can be shaped to create a vacuum during some positions of its movement. Additionally or alternatively, the negative pressure source can be a cylinder of the first cylinder group, wherein the intake stroke of the cylinder 1, 4 can create a sufficient amount of vacuum to supply the second cylinder group intake passage 5B with vacuum. In any case, the intake in the second cylinder group intake passage 5B, the second cylinder group intake passage 5C and the second cylinder group cylinders 2, 3 can flow to the negative pressure source 11 via the negative pressure line 11a.

[0094] The exhaust lines of the two cylinder groups merge in each case with the formation of the outlet manifold 8A, 8B of the particular group to form the total exhaust line 7. The outlet manifold 8B of the second group, that is to say the second group outlet manifold 8B, is equipped with a closing element 10b that stops the exhaust of exhaust gases from the cylinders 2, 3 of the second group during partial deactivation of the internal combustion engine. The closing element 10b can be referred to as an exhaust throttle 10b. Figure 1 In the embodiment shown, the outlet-side closing element 10b is arranged in the second cylinder group exhaust passage 7B between the cross-over point 3 and the second outlet manifold 8B. Here, the closing element 10b can be referred to as an exhaust throttle 10b.

[0095] More specifically, the first cylinder group comprises a first cylinder group exhaust passage 7a and the second cylinder group comprises a second cylinder group exhaust passage 7c. The second cylinder group exhaust passages 7c merge to form a second cylinder group exhaust passage 7B. The second cylinder group exhaust passage 7B and the first cylinder group exhaust passage 7a can merge at the cross-over point 3, thereby forming a main exhaust passage 7.

[0096] A negative pressure line 11b is arranged with a closing element 11b' and connectable to a negative pressure source 11 by opening the closing element 11b' branches off from the second cylinder group exhaust passage 7B between the exhaust throttle 10b and the second cylinder group outlet manifold 8B of the second group.

[0097] The negative pressure lines 11a, 11b allow gases located or trapped in the deactivated cylinders 2, 3 or corresponding passages thereof to be discharged during partial deactivation. As a result of the reduced gas pressure, charge exchange losses of the second cylinder group during partial deactivation can be reduced. In some examples, the negative pressure line 11a can be omitted and the vacuum can be supplied by the negative pressure line 11b only. Gases from the second cylinder group intake passages 5b and 5c can be drawn in via the vacuum generated by the cylinders in the second cylinder group and fed to the negative pressure line 11b.

[0098] In this way, the engine 1 comprises a main throttle 62 arranged in the main intake passage 5, the main throttle 62 being configured to receive instructions from a controller to adjust the amount of air flowing into the engine 1. The main intake passage 5 is split to form an outer intake passage corresponding to the outer cylinders of the engine 1 and an inner intake passage corresponding to the inner cylinders of the engine 1. More specifically, the engine 1 can comprise a first cylinder group comprising the outer cylinders 1, 4 and a second cylinder group comprising the inner cylinders 2, 3. The main intake passage 5 is split into a first cylinder group intake passage 5a and a second cylinder group intake passage 5b. The second cylinder group intake passage 5b comprises a secondary throttle 10a configured to meter the amount of air flowing into the cylinders of the second cylinder group. The second cylinder group intake passage 5b can split into second cylinder group intake passages 5c downstream of the secondary throttle 10a.

[0099] Similarly, the second cylinder group can comprise a second cylinder group exhaust passage 7c which can merge to form a single second cylinder group exhaust passage 7b. An exhaust throttle 10b can be arranged in the second cylinder group exhaust passage 7b between the crossover point 3 and the second cylinder group exhaust passage 7c. The first cylinder group exhaust passage 7a and the second cylinder group exhaust passage 7b can merge at the crossover point 3 to form a main exhaust passage 7.

[0100] The vacuum generating device 11 can be fluidly coupled to the second cylinder group intake passage 5b and the exhaust passage 7b. More specifically, the vacuum generating device 11 can be fluidly coupled to the second cylinder group intake passage 5b at a location between the secondary throttle 10a and the second cylinder group intake passage 5c. Similarly, the vacuum generating device 11 can be further coupled to the second cylinder group exhaust passage 7b at a location between the exhaust throttle 10b and the second cylinder group exhaust passage 7c. The vacuum generating device 11 can be configured to draw out gases trapped between the exhaust throttle 10b and the secondary throttle 10a. More specifically, gases trapped in the second cylinder group intake, exhaust passages and cylinders during cylinder deactivation can be removed therefrom via the vacuum generating device 11. This can reduce the pumping losses incurred by the previous examples described above during cylinder deactivation.

[0101] As such, the method of the engine 1 can include adjusting the secondary throttle and the exhaust throttle to the fully closed position when the cylinders of the second cylinder bank are deactivated. The primary throttle can be adjusted to a more closed position and the cylinders of the first cylinder bank can be adjusted to correspond to a higher load. Thus, the engine can operate with the cylinders of the first cylinder bank combusting and the cylinders of the second bank deactivated, wherein the second cylinder bank does not receive ambient air from the intake passage 5 or expel exhaust to the exhaust passage 7.

[0102] To remove the gas stored around and in the second cylinder bank, a vacuum generating device can draw the gas therefrom to lower the pressure of the second cylinder bank to substantially equal the vacuum generating device. By actuating a closing element disposed in the negative pressure line to a more open position, a vacuum can flow to the second cylinder bank intake passage and the second cylinder bank intake exhaust passage. This can improve fuel efficiency during cylinder deactivation operation. As noted above, the vacuum generating device can include one or more of a brake booster, an EGR valve, a primary throttle, and a cylinder of the first cylinder bank.

[0103] Figure 2 An example of a cylinder of an internal combustion engine 100 included in an engine system 4 of a vehicle 15 is depicted. The engine 100 can be similar to the engine 1 of Figure 1 The engine 100 can be controlled at least in part by a control system including the controller 12 and inputs by a vehicle operator 130 via input devices 132. In this example, the input devices 132 include an accelerator pedal and a pedal position sensor 134 to generate a proportional pedal position signal PP. The cylinder 14 of the engine 100 (which can be referred to herein as a combustion chamber) can include a combustion chamber wall 136 within which a piston 138 is positioned. The piston 138 can be coupled to a crankshaft 140 such that the reciprocating motion of the piston is converted to rotational motion of the crankshaft. The crankshaft 140 can be coupled to at least one drive wheel of a passenger vehicle via a transmission system. Further, a starter motor (not shown) can be coupled to the crankshaft 140 via a flywheel to enable starting operations of the engine 100.

[0104] The cylinder 14 can receive intake air via a series of intake passages 142, 144, and 146. In addition to the cylinder 14, the intake passage 146 can also communicate with other cylinders of the engine 100. Figure 1An engine 100 is shown configured with a turbocharger 175 including a compressor 174 disposed between intake passages 142 and 144 and an exhaust turbine 176 disposed along an exhaust passage 148. Compressor 174 can be powered at least in part by exhaust turbine 176 via a shaft 180. A throttle 162 including a throttle plate 164 can be disposed along an intake passage of the engine for varying the flow rate and / or pressure of intake air provided to the engine cylinders. For example, throttle 162 can be located downstream of compressor 174 as shown, or alternatively can be disposed upstream of compressor 174. Figure 1

[0105] In addition to cylinder 14, exhaust passage 148 can receive exhaust from other cylinders of engine 100. An exhaust sensor 128 is shown coupled to exhaust passage 148 upstream of an emissions control device 178. Sensor 128 can be selected from a variety of suitable sensors to provide an indication of exhaust air / fuel ratio, such as, for example, a linear oxygen sensor or UEGO (universal or wide range exhaust gas oxygen), a dual state oxygen sensor or EGO (as depicted), a HEGO (heated EGO), a NO X , HC or CO sensor. Emissions control device 178 can be a three-way catalyst (TWC), a NO X x-trap, various other emissions control devices, or combinations thereof.

[0106] Each cylinder of engine 100 can include one or more intake valves and one or more exhaust valves. For example, cylinder 14 is shown including at least one intake poppet valve 150 and at least one exhaust poppet valve 156 located in an upper region of cylinder 14. In some examples, each cylinder of engine 100 (including cylinder 14) can include at least two intake poppet valves and at least two exhaust poppet valves located in an upper region of the cylinder. Cylinder 14 can be used similarly to cylinders 1, 2, 3, or 4 of Figure 1 .

[0107] ​The intake valves 150 can be controlled by the controller 12 via actuators 152. Similarly, the exhaust valves 156 can be controlled by the controller 12 via actuators 154. Under some conditions, the controller 12 can vary the signals provided to the actuators 152 and 154 to control the opening and closing of the respective intake and exhaust valves. The position of the intake valves 150 and exhaust valves 156 can be determined by respective valve position sensors (not shown). The valve actuators can be electrically actuated valve actuation or cam actuated or a combination thereof. The intake valve timing and exhaust valve timing can be controlled simultaneously or any of variable intake cam timing, variable exhaust cam timing, dual independent variable cam timing, or fixed cam timing can be used. Each cam actuation system can include one or more cams and can utilize one or more of cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT), and / or variable valve lift (VVL) systems that can be operated by the controller 12 to vary the valve operation. For example, the cylinder 14 can alternatively include intake valves controlled via electrically actuated valve actuation and exhaust valves controlled via cam actuation including CPS and / or VCT. In other examples, the intake and exhaust valves can be controlled by a common valve actuator or actuation system, or a variable valve timing actuator or actuation system.

[0108] The cylinder 14 can have a compression ratio, which is the ratio of the volume when the piston 138 is at bottom center to the volume at top center. In one example, the compression ratio is in the range of 9: 1 to 10: 1. However, in some examples using different fuels, the compression ratio can be increased. This can occur, for example, when using a higher octane fuel or a fuel with a higher latent heat of vaporization. If direct injection is used, the compression ratio can also be increased due to its effect on engine knock.

[0109] In some examples, each cylinder of the engine 100 can include a spark plug 192 for initiating combustion. In the selected mode of operation, the ignition system 190 can provide an ignition spark to the cylinder 14 via the spark plug 192 in response to a spark advance signal SA from the controller 12. However, in some embodiments, the spark plug 192 can be omitted, for example, in the case that the engine 10 can initiate combustion by auto-ignition or fuel injection, as in the case of some diesel engines.

[0110] In some examples, each cylinder of engine 10 can be configured with one or more fuel injectors for providing fuel thereto. By way of non-limiting example, cylinder 14 is shown as including two fuel injectors 166, 170. Fuel injectors 166 and 170 can be configured to deliver fuel received from fuel system 18. Fuel system 18 can include one or more fuel tanks, fuel pumps, and a fuel rail. Fuel injector 166 is shown as being directly coupled to cylinder 14 for directly injecting fuel therein in proportion to a pulse width of a signal FPW-1 received from controller 12 via electronic driver 168. In this manner, fuel injector 166 provides so-called direct injection of fuel into combustion cylinder 14 (hereinafter "DI"). Although Figure 1 Injector 166 is shown positioned on one side of cylinder 14, but it can alternatively be positioned on the top of the piston, such as proximate to spark plug 192. This location can improve mixing and combustion when operating the engine with alcohol-based fuels due to the lower volatility of some alcohol-based fuels. Alternatively, the injector can be positioned on the top and near the intake valve to improve mixing. Fuel can be delivered to fuel injector 166 from a fuel tank of fuel system 18 via a high pressure fuel pump and fuel rail. Further, the fuel tank can have a pressure transducer that provides a signal to controller 12.

[0111] Fuel injector 170 is shown as being disposed in intake passage 146 rather than in cylinder 14, which is configured to provide so-called port fuel injection (hereinafter "PFI") into the intake passage upstream of cylinder 14. Fuel injector 170 can inject fuel received from fuel system 18 in proportion to a pulse width of a signal FPW-2 received from controller 12 via electronic driver 171. Note that a single driver 168 or 171 can be used for both fuel injection systems, or as depicted, multiple drivers can be used, e.g., driver 168 for fuel injector 166 and driver 171 for fuel injector 170.

[0112] In alternative examples, each of fuel injectors 166 and 170 can be configured as direct fuel injectors for injecting fuel directly into cylinder 14. In yet another example, each of fuel injectors 166 and 170 can be configured as port fuel injectors for injecting fuel into the intake passage upstream of intake valve 150. In other examples, cylinder 14 can include only a single fuel injector that is configured to receive different fuels from the fuel system as a fuel mixture in varying relative amounts, and further configured to inject the fuel mixture directly into the cylinder as a direct fuel injector, or to inject the fuel mixture into the intake passage upstream of the intake valve as a port fuel injector.

[0113] Both injectors can deliver fuel to the cylinder in a single cylinder cycle. For example, each injector can deliver a portion of the total fuel injection that is combusted in cylinder 14. Further, the split and / or relative amount of fuel delivered from each injector can change with operating conditions, such as engine load, knock, and exhaust gas temperature, as described below. Intake port injected fuel can be delivered during an intake valve open event, delivered during an intake valve close event (e.g., substantially prior to the intake stroke), and delivered during both intake valve open and intake valve close operations. Similarly, for example, direct injected fuel can be delivered during the intake stroke, and delivered during a portion of the previous exhaust stroke, during the intake stroke, and during a portion of the compression stroke. Thus, even for a single combustion event, injected fuel can be injected at different timings from the intake port injector and the direct injector. Moreover, for a single combustion event, multiple injections of delivered fuel can be performed in each cycle. Multiple injections can be performed during the compression stroke, the intake stroke, or any suitable combination thereof.

[0114] Here, the operation of intake valve 150 can be described in more detail. For example, intake valve 150 can move from a fully open position to a fully closed position, or to any position therebetween. The fully open position allows more air from intake passage 146 to enter cylinder 14 than any other position of intake valve 150 for all identical conditions (e.g., throttle position, vehicle speed, pressure, etc.). Conversely, the fully closed position can prevent air from intake passage 146 from entering cylinder 14 and / or allow the least amount of air from intake passage 146 to enter cylinder 14 than any other position of intake valve 150. Thus, positions between the fully open position and the fully closed position can allow varying amounts of air to flow between intake passage 146 and cylinder 14. In one example, moving intake valve 150 to a more open position allows more air to flow from intake passage 146 to cylinder 14 than an initial position of intake valve 150.

[0115] Fuel injectors 166 and 170 can have different characteristics. This includes differences in size, for example, one injector can have a larger injection orifice than the other. Other differences include, but are not limited to, different spray angles, different operating temperatures, different aim, different injection timing, different spray characteristics, different locations, etc. Moreover, different effects can be achieved depending on the split ratio of fuel injected between injectors 170 and 166.

[0116] The fuel tanks in the fuel system 18 can hold fuel of different fuel types, such as fuels having different fuel qualities and different fuel compositions. These differences can include different alcohol content, different water content, different octane ratings, different heat of vaporization, different fuel mixtures, and / or combinations thereof, among others. One example of fuels having different heat of vaporization can include gasoline as a first fuel type having a lower heat of vaporization and ethanol as a second fuel type having a greater heat of vaporization. In another example, the engine can use gasoline as a first fuel type and an alcohol-containing fuel mixture, such as E85 (which is approximately 85% ethanol and 15% gasoline) or M85 (which is approximately 85% methanol and 15% gasoline) as a second fuel type. Other possible substances include water, methanol, mixtures of alcohol and water, mixtures of water and methanol, mixtures of alcohol, etc.

[0117] The controller 12 is shown in Figure 1 FIG. 1 as a microcomputer, which includes a microprocessor unit 106, input / output ports 108, an electronic storage medium (shown in this particular example as a read-only memory chip 110 for storing executable instructions) for executable programs and calibration values, a random access memory 112, a non-volatile memory (KAM) 114, and a data bus. The controller 12 can receive various signals from sensors coupled to the engine 100, including, in addition to those previously discussed, a measurement of intake mass air flow (MAF) from a mass air flow sensor 122, a measurement of engine coolant temperature (ECT) from a temperature sensor 116 coupled to the cooling jacket 118, a measurement of surface ignition sensing signal (PIP) from a Hall effect sensor 120 (or other type sensor) coupled to the crankshaft 140, a measurement of throttle position (TP) from a throttle position sensor, and a measurement of absolute manifold pressure signal (MAP) from a sensor 124. An engine speed signal RPM can be generated by the controller 12 from the signal PIP. The manifold pressure signal MAP from the manifold pressure sensor can be used to provide an indication of the vacuum or pressure in the intake manifold. The controller 12 can infer engine temperature based on the engine coolant temperature.

[0118] As noted above, Figure 1 Only one cylinder of the multi-cylinder engine is shown. Thus, each cylinder can similarly include its own set of intake / exhaust valves, fuel injector(s), spark plug, etc. It will be understood that the engine 100 can include any suitable number of cylinders, including 2, 3, 4, 5, 6, 8, 10, 12, or more cylinders. Further, each of these cylinders can include some or all of the various components described and depicted with reference to the cylinder 14. Figure 1 described and depicted with reference to the cylinder 14.

[0119] In some examples, vehicle 15 may be a hybrid vehicle having multiple torque sources available for one or more wheels 55. In other examples, vehicle 15 is a conventional vehicle with only an engine. In the example shown, vehicle 15 includes an engine 100 and an electric motor 52. The electric motor 52 may be a motor or a motor / generator (M / G). When one or more clutches 56 are engaged, the crankshaft 140 of engine 100 and electric motor 52 are connected to the wheels 55 via a transmission 54. In the depicted example, a first clutch 56 is disposed between the crankshaft 140 and the electric motor 52, and a second clutch 56 is disposed between the electric motor 52 and the transmission 54. Controller 12 may send signals to the actuators of each clutch 56 to engage or disengage the clutch, thereby connecting or disconnecting the crankshaft 140 from the electric motor 52 and its connected components, and / or connecting or disconnecting the electric motor 52 from the transmission 54 and its connected components. Transmission 54 may be a gearbox, a planetary gear system, or another type of transmission. The powertrain may be configured in various ways, including parallel, series, or series-parallel hybrid vehicles.

[0120] The motor 52 receives electrical power from the energy storage device 58 (hereinafter referred to as battery 58) to provide torque to the wheel 55. For example, during braking operations, the motor 52 can also operate as a generator to provide power to charge the battery 58. In some examples, the motor 52 may be coupled to the turbine 176, as will be described in more detail below.

[0121] Controller 12 receives from Figure 2 The signals from various sensors, and employing Figure 2 Various actuators adjust engine operation based on received signals and instructions stored in the controller's memory. For example, adjusting the rotational speed and direction of turbine 176 may include adjusting signals provided to the actuators of turbine 176 by controller 12. In some examples, the rotational speed and direction of turbine 176 are adjusted in response to cold start and pressure in the intake and exhaust passages. Thus, turbine 176 (and therefore compressor 174) can rotate in both a forward and reverse direction, where the forward direction results in boost flow to engine 100, and where the reverse direction results in increased exhaust back pressure and decreased manifold pressure.

[0122] Now go to Figure 3 This illustrates a method 300 for adjusting air and vacuum flow to the second cylinder bank during certain engine operating parameters. Instructions for executing method 300 can be given by a controller based on instructions stored in the controller's memory and in conjunction with data from sensors in the engine system (such as those referenced above). Figure 2The signals received by the sensors) to perform. According to the methods described below, the controller can employ engine actuators of the engine system to adjust engine operation.

[0123] The method 300 begins at 302, which can include determining, estimating, and / or measuring current engine operating parameters. The current engine operating parameters can include, but are not limited to, one or more of a main throttle position, an engine temperature, an engine speed, a manifold pressure, a vehicle speed, an exhaust gas recirculation flow rate, and an air / fuel ratio.

[0124] The method can proceed to 304, which can include determining whether a second cylinder group is deactivated. As described above, the second cylinder group can be deactivated in response to the engine load being less than a threshold load. The second cylinder group can include Figure 1 cylinders 2 and 3. The threshold load can be based on a percentage of the total engine load. For example, if the current load is equal to 50% or less of the total engine load, the second cylinder group can be deactivated. Regardless, if the second cylinder group is not deactivated, the method 300 can proceed to 306 to maintain the current engine operating parameters and not close exhaust and intake throttle valves associated only with the second cylinder group. The closing elements 10a and 10b of Figure 1 may use exhaust and intake throttle valves associated only with the second cylinder group.

[0125] If the second cylinder group is deactivated, the method 300 can proceed to 308, which can include closing exhaust and intake throttle valves associated with the second cylinder group. Air in the second cylinder group intake and exhaust passages can be hermetically sealed from an upstream portion of the intake system and a downstream portion of the exhaust system. As such, the intake and exhaust passages of the second cylinder group can be hermetically sealed from the main intake and exhaust passages. In this way, no more intake air can flow to the second cylinder group and no exhaust can flow from the second cylinder group to the turbine, ambient atmosphere, or the rest of the exhaust system.

[0126] The method 300 can proceed to 310, which can include flowing a vacuum to the intake and exhaust lines associated with the second group. Air and exhaust trapped between the intake and exhaust throttle valves of the second group can be drawn out by a vacuum generating device, negative pressure device, or the like. By drawing the gases out of the second cylinder group, pumping losses therein can be reduced and / or eliminated. Flowing the vacuum can include moving the closing elements 11a’ and 11b’ to a more open position. In some examples, the vacuum generating device can be a brake booster, an EGR valve, or other device that consumes and / or generates a vacuum to operate. Additionally or alternatively, such as the main throttle valve (e.g., Figure 1The vacuum generating device of the throttle 162) can include one or more features shaped to create a vacuum in the intake air based on its location. As such, gas from the second cylinder group can flow to the first cylinder group and be combusted therein.

[0127] Additionally or alternatively, the first cylinder group can draw gas from the second cylinder group via negative pressure generated by piston oscillation. More specifically, the intake stroke of the pistons of the first cylinder group can be used to draw gas from the second cylinder group, where the gas can be used for combustion. A control valve or check valve can be disposed in a passage fluidly coupling the first cylinder group to the second cylinder group. The control valve or check valve can open in response to the pressure of the first cylinder group being less than the pressure of the second cylinder group. Operating parameters of the first cylinder group can be adjusted to account for receiving intake air and exhaust gas of the second cylinder group. The adjustment can include adjusting fuel injection timing or volume, spark timing, EGR flow rate, throttle position, and air / fuel ratio. For example, the EGR flow rate can be decreased in response to receiving gas from the second cylinder group.

[0128] In one example, additionally or alternatively, the first cylinder group can be a first vacuum source corresponding to a first vacuum passage (e.g., vacuum line 11a) fluidly coupled to a portion of the second cylinder group intake passage between the second cylinder group and the secondary throttle. A different second vacuum source (such as a primary throttle, brake booster, EGR valve) can correspond to a second vacuum passage fluidly coupled to a portion of the second cylinder group exhaust passage between the second cylinder group and the exhaust throttle. In this way, the first cylinder group can be a vacuum source for the second cylinder group, where the first cylinder group only draws intake air and does not draw exhaust.

[0129] The method 300 can proceed to 312, which can include determining whether the second group is reactivated. If the second cylinder group is not reactivated and the cylinders remain deactivated, the method 300 can proceed to 314, which can include maintaining the exhaust throttle and intake throttle closed and keeping the vacuum provided to the second cylinder group. In some examples, if the pressure of the second cylinder group is equal to the pressure of the vacuum source, the vacuum flow to the second cylinder group can be terminated.

[0130] If the second cylinder group is reactivated, the method 300 can proceed to 316, which can include stopping the vacuum flow to the intake and exhaust lines of the second cylinder group. This can include actuating the control valve to a closed position, such as the closed elements 11a, 11b in the negative pressure line shown. Figure 1

[0131] The method 300 can proceed to 318, which can include opening the exhaust throttle and secondary intake throttle of the second cylinder group so that air can flow to the second cylinder group and exhaust can flow out of the second cylinder group.​

[0132] Method 300 can proceed to 320, which can include fueling the cylinders of the second cylinder group. This can further include adjusting the position of the main throttle.

[0133] Turning now to Figure 4 which shows an engine operation sequence 400 illustrating method 300 performed by an internal combustion engine incorporating Figure 1 and Figure 2 Figure 3 Curve 405 depicts activity of the second cylinder group, curve 410 depicts the position of the secondary throttle, curve 415 depicts the position of the exhaust throttle, curve 420 depicts the second cylinder group pressure, and curve 425 depicts whether vacuum is flowing to the second cylinder group.

[0134] Prior to ti, the second cylinder group is active (curve 405). Thus, the cylinders of the second cylinder group can continue to combust. Both the secondary throttle and the exhaust throttle are in an open position (curves 410 and 415, respectively). The open and closed positions can correspond to a fully open position and a fully closed position, with the fully open position allowing a maximum amount of gas flow and the fully closed position allowing a minimum amount of gas flow or substantially no gas flow. The secondary throttle and the exhaust throttle can be actuated to a position between the fully closed position and the fully open position to further meter the gas flow rate. As intake air and exhaust gas reside in the second cylinder group, the second cylinder group pressure is relatively high (curve 420). Vacuum flow is off (curve 425).

[0135] At ti, the second cylinder group is deactivated. In response, the secondary throttle position and the exhaust throttle position can begin to be adjusted toward the fully closed position. As the gas in the second cylinder group exhaust passage and the second cylinder group intake passage is trapped therein, the second cylinder group pressure can remain relatively high. Vacuum flow remains off.

[0136] Between ti and t2, vacuum can begin to flow to the second cylinder group intake passage and the second cylinder group exhaust passage. As a result, the second cylinder group pressure can begin to drop to a relatively low pressure. Vacuum flow can continue to flow to the second cylinder group intake passage and the second cylinder group exhaust passage until the pressure of the second cylinder group is substantially equal to the vacuum flow. With the secondary throttle and the exhaust throttle remaining in the fully closed position, gas flow into and out of the second cylinder group can be substantially prevented. The second cylinder group can remain deactivated, with its overall efficiency increasing due to the higher load placed on the operating cylinders (e.g., the first cylinder group) and the prevention of pumping losses experienced in the second cylinder group.

[0137] ​In some examples, additionally or alternatively, the vacuum can flow only to the second cylinder bank exhaust passage and can not flow to the second cylinder bank intake passage. In this way, gas can be removed from the second cylinder bank via the vacuum flowing to the second cylinder bank exhaust passage and via the vacuum created by the cylinders of the second cylinder bank. More specifically, the cylinders of the second cylinder bank can expel gas disposed in the second cylinder bank intake passage to the second cylinder bank exhaust passage, where the gas can be drawn via the negative pressure device.

[0138] At t2, the vacuum flow is deactivated. The secondary throttle and the exhaust throttle are moved from the fully closed position to a more open position. This can allow the second cylinder bank pressure to increase in anticipation of the cylinders of the second cylinder bank being activated. The second cylinder bank is activated and the second cylinder bank pressure increases to a relatively high pressure.

[0139] In this way, gas in the deactivated cylinder can be expelled via a vacuum source. The technical effect of removing gas from the deactivated cylinder can improve fuel efficiency during cylinder deactivation. Additionally, various pre-existing vacuum sources can be fluidly coupled to the passages of the deactivated cylinder, thereby reducing manufacturing costs and packaging constraints.

[0140] An example of an internal combustion engine includes at least one cylinder head having at least two cylinders, where each of the two cylinders has at least one inlet opening fluidly coupled to an intake line for supplying fresh air via an intake system, each cylinder has at least one outlet opening fluidly coupled to an exhaust line for discharging exhaust gas via an exhaust emission system, the at least two cylinders form a first cylinder bank and a second cylinder bank, the first cylinder bank includes at least a first cylinder and the second cylinder bank includes at least a second cylinder different from the first cylinder, where the first cylinder is non-switchable and the second cylinder is switchable; an intake system including a primary shut-off element configured to regulate fresh air flow to each of the first cylinder bank and the second cylinder bank and a secondary shut-off element configured to regulate fresh air flow to only the second cylinder bank, via which the supply of fresh air to at least one cylinder of the second bank can be stopped; a second cylinder bank exhaust line equipped with at least one exhaust shut-off element configured to regulate exhaust gas flow from the second cylinder bank exhaust line to the exhaust emission system; and a negative pressure source fluidly coupled to at least the second cylinder bank exhaust line, where a negative pressure line fluidly coupling the negative pressure source is connected to the second cylinder bank exhaust line at a location between the exhaust shut-off element and the second cylinder.

[0141] The first example of the internal combustion engine further includes, wherein the main shut-off element is arranged in the main intake line, the main intake line is split downstream of the main shut-off element to form the first bank intake line and the second bank intake line, and wherein the secondary throttle is arranged in the second bank intake line. The second example of the internal combustion engine optionally includes the first example, further including wherein the negative pressure line is a first negative pressure line, and wherein a second negative pressure line fluidly couples the negative pressure source to a portion of the second bank intake line between the secondary shut-off element and the second cylinder, and wherein each of the first negative pressure line and the second negative pressure line includes a first control valve and a second control valve, respectively. The third example of the internal combustion engine optionally includes the first example and / or the second example, further including wherein the controller has computer readable instructions stored thereon that, when executed, enable the controller to capture gas between the exhaust shut-off element and the second shut-off element when the second cylinder is deactivated; and the instructions further include adjusting the first control valve and the second control valve to a more open position in response to the second cylinder being deactivated. The fourth example of the internal combustion engine optionally includes one or more of the first through third examples, further including wherein the negative pressure source includes one or more of a vacuum pump, a negative pressure area of an intake system, a first cylinder, a brake booster, or a vacuum actuated valve.

[0142] Examples of the system include: an engine including a first cylinder bank having at least a first cylinder and a second cylinder bank having at least a second cylinder, wherein only the second cylinder can be deactivated; a main intake throttle disposed in a main intake passage, the main throttle shaped to regulate air flow to the first cylinder bank and the second cylinder bank, and wherein the main intake passage splits downstream of the main throttle into a first cylinder bank intake passage and a second cylinder bank intake passage; a secondary intake throttle disposed in the second cylinder bank intake passage, the secondary intake throttle shaped to regulate air flow to only the second cylinder; an exhaust throttle disposed in the second cylinder bank exhaust passage, the exhaust throttle shaped to regulate exhaust flow out of only the second cylinder, and wherein a first cylinder bank exhaust passage fluidly couples to the first cylinder, wherein the first cylinder bank exhaust passage merges with the second cylinder bank exhaust passage downstream of the exhaust throttle; a vacuum source fluidly coupled to a portion of the second cylinder bank exhaust passage between the exhaust throttle and the second cylinder via a vacuum line including a control valve; and a controller having computer readable instructions stored on a non-transitory memory of the controller that, when executed, enable the controller to regulate the control valve and flow vacuum from the vacuum source to the second cylinder bank exhaust passage in response to the second cylinder being deactivated. A first example of the system further includes wherein the instructions further include regulating the secondary intake throttle and the exhaust throttle to closed positions in response to the second cylinder being deactivated. A second example of the system optionally includes the first example, further including wherein the vacuum source is a first vacuum source, and wherein the vacuum line is a first vacuum line, further including a second vacuum line extending from a second vacuum source, the second vacuum line fluidly coupling the second vacuum source to a portion of the second cylinder bank intake passage between the second cylinder and the secondary intake throttle. A third example of the system optionally includes the first example and / or the second example, further including wherein the first vacuum source and the second vacuum source are different, and wherein the first vacuum source and the second vacuum source are a brake booster, an EGR valve, a main throttle, and the first cylinder. A fourth example of the system optionally includes one or more of the first through third examples, further including wherein the first vacuum source is the brake booster or the EGR valve, and wherein the second vacuum source is the main throttle or the first cylinder. A fifth example of the system optionally includes one or more of the first through fourth examples, further including wherein exhaust from the first cylinder bank mixes with exhaust from the second cylinder bank downstream of the exhaust throttle. A sixth example of the system optionally includes one or more of the first through fifth examples, further including wherein the first cylinder bank receives greater than or equal to an air flow of the second cylinder bank. A seventh example of the system optionally includes one or more of the first through sixth examples, further including wherein the main throttle creates a vacuum as air flows around or through the main throttle.

[0143] Embodiments of the method include deactivating only a second cylinder group of the engine, the second cylinder group including at least one cylinder different from at least one cylinder in the first cylinder group; closing intake and exhaust air valves configured to regulate air flow into and from only the second cylinder group, respectively; and removing gas between the intake and exhaust air valves via a vacuum source. A first example of the method further includes a main intake passage containing a main intake air valve shaped to regulate intake air flow to each of the first and second cylinder groups, and wherein the main intake passage splits downstream of the main intake air valve to form a first cylinder group intake passage and a second cylinder group intake passage, and wherein intake air flows freely in the first cylinder group intake passage and is regulated in the second cylinder group intake passage via the intake air valve. A second example of the method optionally includes the first example, further including wherein the first cylinder group includes a first cylinder group exhaust passage fluidically separate from a second cylinder group exhaust passage of the second cylinder group, and wherein the exhaust air valve is disposed in the second cylinder group exhaust passage. A third example of the method optionally includes the first and / or second example, further including wherein removing gas further includes regulating a position of a control valve in a vacuum line fluidically coupling the vacuum source to a portion of the second cylinder group exhaust passage between the second cylinder and the exhaust air valve. A fourth example of the method optionally includes one or more of the first through third examples, further including wherein the vacuum line is a first vacuum line and the control valve is a first control valve, further including a second vacuum line different from the first vacuum line, the second vacuum line including a second control valve, the second control valve regulated independently of the first control valve. A fifth example of the method optionally includes one or more of the first through fourth examples, further including wherein the first and second cylinder groups include the same number of cylinders, and wherein the first cylinder group includes at least a first cylinder and the second cylinder group includes at least a second cylinder. A sixth example of the method optionally includes one or more of the first through fifth examples, further including wherein the vacuum source is one or more of a vacuum pump, a brake booster, an EGR valve, and a first cylinder.

[0144] It should be noted that the example control and estimation procedures included herein can be used in different engine and / or vehicle system configurations. The control methods and procedures disclosed herein can be stored as executable instructions in non-transitory memory and can be executed by a control system including a controller in combination with various sensors, actuators, and other engine hardware. The specific procedures disclosed herein can represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and so on. As such, the various steps, operations, or functions illustrated can be implemented in the order

[0145] It should be understood that the configurations and procedures disclosed herein are exemplary in nature, and that these specific embodiments should not be taken as limiting the scope of the present disclosure, as there can be numerous variations and modifications thereof. For example, the above-described techniques can be applied to V-6, I-4, I-6, V-12, opposed 4 cylinder, and other engine types. The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems and configurations disclosed herein, as well as other features, functions, and / or properties noted herein.

[0146] The appended claims particularly point out certain combinations and subcombinations considered to be novel and nonobvious. These claims can refer to "an" element or "a first" element and the equivalent thereof, meaning one or more than one such element. The specification, however, should be read to mean one or more such elements, whether or not further iterations are explicitly mentioned. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties can be claimed through amendment of the current claims or presentation of additional claims in the application or continuation-in-part application. Such amended or new claims, whether they are directed to a different, unrelated, or unrelated art than any previously-stated application claims, are to be accepted as included in this original application if the claims depend from the same base claims as the original application. This application is only being submitted under 35 U.S.C. § 111(a) or 365.

Claims

1. An internal combustion engine, comprising: at least one cylinder head having at least two cylinders, wherein each of the two cylinders has at least one inlet opening fluidly coupled to an intake line for supplying fresh air via an intake system, each cylinder has at least one outlet opening fluidly coupled to an exhaust line for discharging exhaust gas via an exhaust emission system, the at least two cylinders form a first cylinder group and a second cylinder group, the first cylinder group includes at least a first cylinder and the second cylinder group includes at least a second cylinder different from the first cylinder, wherein the first cylinder is non-switchable and the second cylinder is switchable; the intake system including a primary shut-off element configured to regulate fresh air flow to each of the first cylinder group and the second cylinder group and a secondary shut-off element configured to regulate fresh air flow to only the second cylinder group, via which the supply of fresh air to the at least one cylinder of the second group can be stopped; a second cylinder group exhaust line equipped with at least one exhaust shut-off element configured to regulate exhaust gas flow from the second cylinder group exhaust line to the exhaust emission system; and a negative pressure source fluidly coupled to at least the second cylinder group exhaust line, wherein a negative pressure line fluidly coupling the negative pressure source is connected to the second cylinder group exhaust line at a location between the exhaust shut-off element and the second cylinder, wherein the negative pressure source is configured to remove gas trapped between the secondary shut-off element and the exhaust shut-off element.

2. The internal combustion engine of claim 1, wherein the primary shut-off element is disposed in a primary intake line, the primary intake line splits downstream of the primary shut-off element to form a first cylinder group intake line and a second cylinder group intake line, and wherein the secondary shut-off element is disposed in the second cylinder group intake line.

3. The internal combustion engine of claim 2, wherein the negative pressure line is a first negative pressure line, and wherein a second negative pressure line fluidly couples the negative pressure source to a portion of the second cylinder group intake line between the secondary shut-off element and the second cylinder, and wherein each of the first negative pressure line and the second negative pressure line includes a first control valve and a second control valve, respectively.

4. The internal combustion engine of claim 3, further comprising a controller having computer readable instructions stored thereon that, when executed, cause the controller to trap gas between the exhaust shut-off element and the secondary shut-off element when the second cylinder is deactivated; and the instructions further include wherein the first control valve and the second control valve are adjusted to a more open position in response to the second cylinder being deactivated.

5. The internal combustion engine of claim 1, wherein the negative pressure source includes one or more of a vacuum pump, a negative pressure region of the intake system, a first cylinder, a brake booster, or a vacuum actuated valve.

6. An engine system, comprising: ​ An engine comprising a first cylinder bank having at least a first cylinder and a second cylinder bank having at least a second cylinder, wherein only the second cylinder is deactivatable; a primary intake throttle disposed in a primary intake passage, the primary intake throttle shaped to regulate air flow to the first cylinder bank and the second cylinder bank, and wherein the primary intake passage splits into a first cylinder bank intake passage and a second cylinder bank intake passage downstream of the primary intake throttle; a secondary intake throttle disposed in the second cylinder bank intake passage, the secondary intake throttle shaped to regulate air flow to only the second cylinder; an exhaust throttle disposed in a second cylinder bank exhaust passage, the exhaust throttle shaped to regulate exhaust flow out of only the second cylinder, and wherein a first cylinder bank exhaust passage is fluidly coupled to the first cylinder, wherein the first cylinder bank exhaust passage merges with the second cylinder bank exhaust passage downstream of the exhaust throttle; a vacuum source fluidly coupled to a portion of the second cylinder bank exhaust passage between the exhaust throttle and the second cylinder via a vacuum line including a control valve; and a controller having computer readable instructions stored on a non-transitory memory of the controller that, when executed, cause the controller to: in response to the second cylinder being deactivated, adjust the control valve and flow vacuum from the vacuum source to the second cylinder bank exhaust passage.

7. The engine system of claim 6, wherein the instructions further comprise adjusting the secondary intake throttle and the exhaust throttle to closed positions in response to the second cylinder being deactivated.

8. The engine system of claim 6, wherein the vacuum source is a first vacuum source, and wherein the vacuum line is a first vacuum line, the system further comprising a second vacuum line extending from a second vacuum source, the second vacuum line fluidly coupling the second vacuum source to a portion of the second cylinder bank intake passage between the second cylinder and the secondary intake throttle.

9. The engine system of claim 8, wherein the first vacuum source and the second vacuum source are different, and wherein the first vacuum source and the second vacuum source are a brake booster, an EGR valve, the primary intake throttle, or the first cylinder.

10. The engine system of claim 9, wherein the first vacuum source is the brake booster or the EGR valve, and wherein the second vacuum source is the primary intake throttle or the first cylinder.

11. The engine system of claim 6, wherein exhaust from the first cylinder bank mixes with exhaust from the second cylinder bank downstream of the exhaust throttle.

12. The engine system of claim 6, wherein the first cylinder bank receives a greater or equal air flow than the second cylinder bank.

13. The engine system of claim 6, wherein the primary intake throttle creates a vacuum as air flows around or through the primary intake throttle.

14. A method for an engine, comprising: deactivating only a second cylinder bank of the engine, the second cylinder bank having a different cylinder than a first cylinder bank; closing an intake throttle and an exhaust throttle, the intake throttle and the exhaust throttle configured to regulate airflow to and from only the second cylinder bank, respectively; and removing trapped gas between the intake throttle and the exhaust throttle via a vacuum source.

15. The method of claim 14, further comprising a main intake passage housing a main intake throttle, the main intake throttle shaped to regulate intake air flow to each of the first cylinder bank and the second cylinder bank, and wherein the main intake passage splits downstream of the main intake throttle to form a first cylinder bank intake passage and a second cylinder bank intake passage, and wherein intake air flows freely in the first cylinder bank intake passage and intake air flow is regulated in the second cylinder bank intake passage via the intake throttle.

16. The method of claim 14, wherein the first cylinder bank includes a first cylinder bank exhaust passage, the first cylinder bank exhaust passage fluidically isolated from a second cylinder bank exhaust passage of the second cylinder bank, and wherein the exhaust throttle is disposed in the second cylinder bank exhaust passage.

17. The method of claim 16, wherein removing gas further comprises regulating a position of a control valve in a vacuum line fluidically coupling the vacuum source to a portion of the second cylinder bank exhaust passage between the second cylinder and the exhaust throttle.

18. The method of claim 17, wherein the vacuum line is a first vacuum line and the control valve is a first control valve, further comprising a second vacuum line different from the first vacuum line, the second vacuum line including a second control valve, the second control valve regulated independently of the first control valve.

19. The method of claim 14, wherein the first cylinder bank and the second cylinder bank include the same number of cylinders, and wherein the first cylinder bank includes at least a first cylinder and the second cylinder bank includes at least a second cylinder.

20. The method of claim 19, wherein the vacuum source is one or more of a vacuum pump, a brake booster, an EGR valve, and the first cylinder.

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