Internal Combustion Engine with Integrated Air Compressor

A piston-cylinder arrangement for an internal combustion engine includes a first cylinder bore in an engine with a first piston disposed therein. A combustion chamber may be positioned between walls of the first cylinder bore and the first piston. A second cylinder bore in the engine block may be aligned with the first cylinder bore with a second piston disposed therein. A compression chamber may be positioned between walls of the second cylinder bore and the second piston. One or more supporting members may connect the first piston to the second piston for facilitating concurrent reciprocation of the first piston and the second piston within their respective cylinder bores during operation of the internal combustion engine. The first piston, the second piston, and the one or more supporting members may define a stacked piston arrangement.

FIELD

The present disclosure relates to piston configurations of internal combustion engines.

BACKGROUND

The provision of compressed air in internal combustion engines is traditionally supplied via an air compression device that is separate from reciprocating pistons used in fuel combustion. Examples of these air compression devices are air compressors run off of engine power (e.g. for supplying air brakes), a turbo charger, and/or a supercharger. For example, most of today's commercial transportation depends on diesel engines and air brakes, whereby air pressure is provided by an engine driven air compressor. These compressors, on the average, are actuated every eleven minutes and use some engine horsepower to do so.

Given the current state of the art for engine driven air compression devices, disadvantages are apparent with respect to available delivery speed and volumes for vehicle combustion, air braking, and/or engine braking requirements. Further, traditional superchargers and turbo chargers are not easily configurable for disconnection when not needed during power cycles of the engine and therefore provide constant or otherwise undesirable parasitic losses.

It is also recognized that for current engine air braking applications, all the compressing and release of air used during engine braking takes place in the fuel burning chamber, giving the disadvantage of negatively affecting the emission system. These disadvantages include increased emissions by expelling unburned fuels and cooling off catalytic converters and other exhaust components.

Further, it is recognized that two stroke engine operation has a disadvantage in terms of poor emission quality. As such, current two stroke internal combustion engines are less efficient than four stroke engines for a number of different reasons; (1) they don't breath well, a four stroke engines has 180° to exhaust and 180° to intake while a two stoke has about 80 to 100° to do both at the same time; (2) using a scavenged design crankcase it is difficult to pass emissions standards, even with direct fuel inject, thanks to the total-loss oiling; and (3) by using a blower charger engine, power is stolen while still retaining exhaust and intake limitations.

SUMMARY

It is an object of the present invention to provide a piston configuration to obviate or mitigate at least some of the above-presented disadvantages.

A first aspect provided is a piston-cylinder arrangement for an internal combustion engine, the arrangement comprising: a first cylinder bore in an engine block, the first cylinder bore having an axis extending along a length of the first cylinder bore; a first piston positioned within the first cylinder bore for reciprocation along the axis; a combustion chamber positioned between walls of the first cylinder bore and the first piston; an inlet for directing intake contents into the combustion chamber; an outlet for directing exhaust contents of the combustion chamber out of the combustion chamber; a second cylinder bore in the engine block, the second cylinder bore aligned with the first cylinder bore along the axis; a second piston positioned within the second cylinder bore for reciprocation along the axis; a compression chamber positioned between walls of the second cylinder bore and the second piston; one or more ports in the engine block for directing air into and out of the compression chamber; and one or more supporting members connecting the first piston to the second piston, the one or more supporting members positioning the first piston and the second piston is a spaced apart relationship for facilitating concurrent reciprocation of the first piston and the second piston within their respective cylinder bores during operation of the internal combustion engine; wherein the first piston, the second piston and the one or more supporting members define a stacked piston arrangement.

A second aspect provided is a control system having a computer processor and associated memory programmed by a set of stored instructions for executing the instructions to operate in a power cycle using two strokes of the stacked piston arrangement as: during a first stroke of the two strokes of the power cycle, the first stroke including travel of the stacked piston arrangement from TDC to BDC: receiving via the position sensing system a signal that the stacked piston is adjacent to TDC; providing for inlet of air from ambient into the compression chamber; opening the tank supply control valve to supply compressed air from the air storage tank to the air inlet port for injection into the combustion chamber via the inlet, the compressed air for use in mixing with fuel for facilitating combustion in the combustion chamber during the first stroke; and during a second stroke of the two strokes of the power cycle, the second stroke including travel of the stacked piston arrangement from BDC to TDC: assessing if air pressure of the air storage tank is above a pressure threshold, and if so then venting the air storage tank; wherein exhaust contents present in the combustion chamber are expelled from the combustion chamber during the second stroke through operation of an exhaust valve in the outlet via the valve control system.

A third aspect provided is a control system having a computer processor and associated memory programmed by a set of stored instructions for executing the instructions to operate in a power cycle of the stacked piston arrangement as: receiving via the position sensing system a signal that the stacked piston arrangement is in position for travel towards BDC; opening the tank control valve to supply compressed air from the air storage tank into the compression chamber; and closing the tank control valve to inhibit the supply of compressed air into the compression chamber during travel of the stacked piston arrangement towards TDC; wherein supply of compressed air in the first supply line from the compression chamber to the air storage tank is inhibited by an outlet valve positioned between the compression chamber and the air storage tank while air pressure introduced by the supply of compressed air into the compression chamber biases travel of the stacked piston arrangement towards BDC.

A fourth aspect provided is a control system having a computer processor and associated memory programmed by a set of stored instructions for executing the instructions to operate in a power cycle of the stacked piston arrangement as: receiving via the position sensing system a signal that the stacked piston arrangement is in position for travel towards BDC; opening at least one of the tank control valve and the ambient control valve to supply air into the compression chamber; and closing the at least one of the tank control valve and the ambient control valve to inhibit egress of air from the compression chamber during travel of the stacked piston arrangement towards TDC; wherein the compression of air in the compression chamber during travel of the stacked piston arrangement towards TDC biases travel of the stacked piston arrangement against travel towards TDC during operation of intake and exhaust in the combustion chamber.

A fifth aspect provided is a control system having a computer processor and associated memory programmed by a set of stored instructions for executing the instructions to operate in a power cycle using four strokes of the stacked piston arrangement as: during a first stroke of the four strokes of the power cycle, the first stroke including travel of the stacked piston arrangement from TDC to BDC: receiving via the position sensing system a signal that the stacked piston is adjacent to TDC; providing for inlet of air from ambient into the compression chamber; opening the tank supply control valve to supply compressed air from the air storage tank to the air inlet port for injection into the combustion chamber via the inlet, the compressed air for use in mixing with fuel for facilitating combustion in the combustion chamber during a second stroke of the power cycle; and during at least one of a second stroke and a fourth stroke of the power cycle, the second stroke and the fourth stroke including travel of the stacked piston arrangement from BDC to TDC: assessing if air pressure of the air storage tank is above a pressure threshold, and if so then venting the air storage tank; wherein exhaust contents present in the combustion chamber are expelled from the combustion chamber during the fourth stroke through operation of an exhaust valve in the outlet via the valve control system.

A sixth aspect provided is the set of stored instructions to operate in the power cycle during at least one of the second stroke and the fourth stroke of the power cycle as: opening the ambient control valve to direct the air out of the compression chamber into ambient rather than into the air storage tank via the first port.

A seventh aspect provided is the set of stored instructions to operate in the power cycle as: positioning the tank supply control valve as closed over a number of the power cycles in series in order to inhibit the supply of compressed air into the inlet while increasing the air pressure in the air storage tank; wherein the internal combustion engine operates in a normally aspirated mode using ambient air collected via the inlet.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring toFIG. 1, shown is a piston-cylinder arrangement50for an internal combustion engine (not shown). The arrangement50has an engine block20with a cylinder head21. It is recognised that one cylinder of the engine block20is shown for exemplary purposes only, recognising that the engine block20could have a plurality of piston-cylinder arrangements50as desired. It is recognised that the engine block20can be incorporated as part of an engine for a vehicle or other application (e.g. generator), as desired. It is also recognised that fuel and corresponding ignition configuration of the engine can be provided as petrol, diesel, propane, hydrogen, or other combustible fuel as desired.

Referring again toFIG. 1, the engine block20has a first cylinder bore52having an axis54extending along a length of the cylinder bore52, the axis54for accommodating reciprocation of a first piston2therein. The piston2is positioned within the cylinder bore52for reciprocation along the axis54and has piston rings56for contacting with walls58of the cylinder bore52. The piston2can also have lubricating oil passages47for facilitating lubrication of the walls58. The piston2, cylinder head21and cylinder bore52cooperate to form a combustion chamber7, positioned between walls58of the cylinder bore52, head surface60of the piston2and cylinder head21.

The cylinder head21has an inlet18for directing intake contents (e.g. air and fuel) into the combustion chamber7, as controlled by an engine intake valve22. The cylinder head21also has an outlet19for directing exhaust contents (e.g. combustion products) of the combustion chamber7out of the combustion chamber7and into an exhaust system62(e.g. exhaust manifold, exhaust pipes, catalytic converter, muffler, emissions sensors, etc.). Timing of ejection of the exhaust contents from the combustion chamber7is controlled via an engine exhaust valve23. A valve control system64is coupled to the valves22,23for coordinating opening and closing of the inlet valve22of the inlet18and the exhaust valve23of the outlet19based on power cycle intake and exhaust timing. It is recognised that examples of the valve control system64can include a valve actuator such as a cam shaft and/or an electronically or pneumatic controlled valve actuator (e.g. solenoid), as is known in the art.

Referring again toFIG. 1, the piston-cylinder arrangement50also has a second cylinder bore66in the engine block20, the second cylinder bore66aligned with the first cylinder bore52along the axis54. A second piston1is positioned within the cylinder bore66for reciprocation along the axis54and has piston rings68for contacting with walls70of the cylinder bore66. The piston1, the engine block20and cylinder bore66cooperate to form a compression chamber8, positioned between walls70of the cylinder bore66, head surface74of the piston1and the engine block20. Provided are one or more ports76in the engine block20for directing air into and/or out of the compression chamber8, as further described below.

The compression chamber8is used to provide a source of compressed air (due to air intake and compression strokes of piston1in cylinder bore66during reciprocation) for use in a number of potential operations. These operations can include such as but not limited to: air boost (i.e. providing variable compression ratios VCR as dictated by the varying the amount of compressed air introduced) to supplement air supplied to the combustion chamber7similar to a turbocharger or supercharger operation; compressed air supply for operation of pneumatically powered vehicle components92such as air brakes or other vehicle components operated by compressed air; assisted engine startup by forcing piston1from TDC to BDC (seeFIG. 3) using compressed air forced into the compression chamber8, hence pneumatic startup of the stacked piston arrangement78(piston1mechanically coupled and fixedly positioned with respect to piston2); aggressive engine braking by forcing compressed air from the air storage tank9into the compression chamber8for further compression in travel of the piston1from BDC to TDC; and/or assisted engine braking by drawing ambient air into the compression chamber8for compression in travel of the piston1from BDC to TDC. It is recognized that use of compressed air generated by the compression chamber8can be provided for in separated and independent air supply circuits82,84, as further described below, thus advantageously facilitating compressed air for VCR to remain separate from compressed air used for non VCR applications (e.g. engine braking, pneumatic operations, etc.).

Referring again toFIG. 1, the first piston2and the second piston1are positioned in a spaced apart relationship by one or more supporting members4connecting the first piston2to the second piston1, for facilitating concurrent reciprocation of the first piston2and the second piston1within their respective cylinder bores52,66during operation of the internal combustion engine. Together, the first piston2, the second piston1and the one or more supporting members4define the stacked piston arrangement78.

The stacked piston arrangement78can be monitored for location in the respective cylinder bores52,66by a position sensing system53for sensing position of the stacked piston arrangement78with respect to respective Top Dead Center (TDC) and respective Bottom Dead Center (BDC) of the cylinder bores52,66. It is recognized that the position sensing system53can be part of the valve control system64, as desired, or otherwise separate there from (e.g. positioned with respect to a crankshaft connecting the second piston1to a load such as a vehicle driveshaft—not shown).

Referring again toFIG. 1, shown is an air system80for coordinating air flow into and out of the compression chamber8. As further discussed below, there are a number of optional configurations for the air system80. In one example, the air system80can have an air supply circuit82(seeFIG. 2) for providing compressed air obtained from the compression chamber8into the engine inlet18. It is recognized in this embodiment that the air system80can be used to provide supplemental air (i.e. compressed air) to the combustion chamber7in addition to what air is provided to the combustion chamber via normal aspiration from ambient29. In another example, the air system80can also have air supply circuit84for collecting compressed air from the compression chamber8as well as introducing compressed air to the compression chamber8based on operational states and requirements of the engine. As further discussed below, air supply circuit84can be used to direct compressed air from the compression chamber8to an air storage tank9for storage, as well as to direct compressed air from the air storage tank9to the compression chamber8.

Referring toFIG. 2, the air supply circuit82can include an air injection port15coupled to the inlet18for directing compressed air from the compression chamber8into the combustion chamber7. The compressed air storage tank9can be positioned between the one or more ports76and the air injection port15, such that the compressed air storage tank9is fluidly connected to the one or more ports76by a first supply line6and fluidly connected to the air injection port15by a second supply line16. The air storage tank9has a control valve13(e.g. solenoid valve) for operation by a air supply control system100(seeFIG. 3) as further described below. As such, timed opening and closing of the control valve13provides for injection of compressed air into the inlet18of the combustion chamber7via supply line16. For example, supply line16can be fluidly connected to a conduit15present in the cylinder head21(as shown) and/or present in the engine block20(not shown), as desired. The supply line16and the inlet18can have one or more control valves32(e.g. directional valves) for coordinating the directional supply of the compressed air to the combustion chamber7. For example, the directional valve32in the inlet18, between the inlet valve22and ambient29, can provide for inhibiting flow of the compressed air from the conduit15to ambient29. Accordingly, the tank supply control valve13controls the supply of compressed air in the supply line16from the air storage tank9to the air injection port15and the outlet valve5facilitates the supply of compressed air in the supply line6from the compression chamber8to the air storage tank9during the compression stroke (e.g. travel from BDC to TDC) of the piston1.

Referring again toFIG. 1, the one or more ports76can include a first port86for directing compressed air from the compression chamber8to the air storage tank9, the first port86cooperating with a release port3positioned in the one or more supporting members4, wherein periodic alignment (seeFIG. 3) between first port86and the release port3during reciprocation51of the second piston1provides for exhaust of compressed air out of the compression chamber8and into the air storage tank9via supply line6. As shown by example, the release port3can be provided as one or more notches in the body of the supporting members4(e.g. columns used to space apart piston2from piston1along the axis54). As shown inFIG. 4, alignment of the release port3in the supporting member4with the first port86in the engine block20provides for fluidly connecting the compressed air contents of the compression chamber8with the supply line6. As shown by example, the supply line6and/or the first port86can include a valve5(e.g. directional valve) for inhibiting backflow of compressed air from the air storage tank9to the compression chamber8, or otherwise facilitating the flow of compressed air from the compression chamber8to the air storage tank9when the release port3and the first port86are aligned.

Referring again toFIG. 2, the air supply circuit84can include the first port86to direct compressed air out of the compression chamber8as well as the one or more ports including a second port36for directing air with respect to the compression chamber8via an ambient control valve26coupled to ambient29. As such, the compression chamber8can be supplied by intake air from ambient29during an intake stroke of the piston1through the second port36. Also, the compression chamber8can direct air out of the compression chamber8and into the air storage tank via tank control valve35using supply line25fluidly connected to valve35and the air supply tank9. The air supply circuit84can also include a third supply line42coupling the air supply tank9to an inlet44of the compression chamber8. Using control valve41, the compressed air in the air storage tank9can be injected into the compression chamber8via air inlet44. Injection of compressed air via air inlet44can be used to fill the compression chamber8from the air storage tank9and thus bias the travel of the piston1from TDC to BDC, as further discussed below.

Referring again toFIG. 2, it is noted that the exhaust system62coupled to the outlet19of the combustion chamber7is used to direct the combustion gases to ambient, while at the same time the air supply circuit84can be used to configure the one or more ports76in the engine block20to direct air out of the compression chamber8to ambient29in a fluid path that bypasses the exhaust system62. As such, it is recognized that the compressed air generated by reciprocation of the piston1can be exhausted to ambient29via the second port36and the ambient control valve26, rather than being injected via the inlet18through the combustion chamber7and exhausted to ambient via the outlet19and coupled exhaust system62. The combustion chamber8bypass provided by the air supply circuit84can be advantageous in air braking applications, as described below, as compressed air from the storage tank9can be used independently for air braking via introduction into the compression chamber8via air port44of the air supply circuit84, which is fluidly separate from the air supply circuit82used to supply the combustion chamber7to supplement combustion of fuel therein. In other words, compressed air used for air braking can remain uncontaminated by combusted fuel as the air supply circuits82,84provide separated and independent fluid paths to ambient29for the compressed air obtained from the air storage tank9.

Referring toFIGS. 1, 2 and 3, shown is the control system100having a computer processor102and associated memory104programmed by a set of stored instructions106for executing the instructions106to operate in a power cycle using two strokes of the stacked piston arrangement78. The control system100has an interface108for receiving and providing control signals110based on information110provided by the position sensing system53, the valve control system64, states of the various valves (e.g. valves5,13,26,32,35,41,43), and/or tank9pressure monitored by pressure sensor12.

In operation of the stacked piston arrangement78, during a first stroke of the two strokes of the power cycle, the first stroke including travel of the stacked piston arrangement78from TDC to BDC (seeFIG. 5), the control system100executes the instructions106to: receive via the position sensing system53a signal110that the stacked piston arrangement78is adjacent to TDC; provide for inlet of air from ambient29into the compression chamber8via operation of the control valve26when the piston1travels as an intake stroke towards BDC; and open the tank supply control valve13to supply compressed air from the air storage tank9to the air inlet port15for injection into the combustion chamber7via the inlet18, the compressed air for use in mixing with fuel for facilitating combustion in the combustion chamber during the first stroke.

In this manner, the travel of the stacked piston arrangement78provides concurrently for 1) injection of ambient air through air port36for piston1operating as an intake stroke (i.e. drawing air from ambient29into the compression chamber8and 2) injection of compressed air into the combustion chamber7for use in subsequent combustion of fuel (i.e. power stroke) to force the piston2from TDC to BDC.

In operation of the stacked piston arrangement78, during a second stroke of the two strokes of the power cycle, the second stroke including travel of the stacked piston arrangement78from BDC to TDC (seeFIG. 4), the control system100can optionally execute the instructions106to: assess if air pressure of the air storage tank9via the pressure sensor12is above a pressure threshold, and if so then venting the air storage tank9.

It is recognized that that venting of the air storage tank9can be achieved by using any appropriate supply line16,42,25to provide a path of exit (and thus pressure decrease) for compressed air from the air storage tank9. It is recognized that the air storage tank9could also be vented to ambient29using a pressure relief valve coupled to the tank9, not shown. It is noted that as the stacked piston arrangement78travels from BDC to TDC, compressed air is generated in the compression chamber8due to travel of the piston1therein and control valve26to ambient is closed. Once the travel of the piston1causes alignment of the release port3and the air port86, the generated compressed air is supplied to the air storage tank9via supply line6. Alternatively to the above, it is recognized that the supply line6can optionally include a pressure relief valve90to vent to ambient29, as desired. It is also recognized that during the second stroke of the power cycle, exhaust contents present in the combustion chamber7are expelled from the combustion chamber7during through operation of the exhaust valve23in the outlet19via the valve control system64.

Options of control exercised by the control system100during operation the stacked piston arrangement78during the power cycle can include: the ambient control valve26is opened to facilitate the venting of the compression chamber8to inhibit compression of air in the compression chamber8during travel of the stacked piston arrangement78from BDC to TDC; the stacked piston arrangement78is traveling towards TDC when the tank supply control valve13is opened to supply the air inlet port15in order to provide compressed air from the air storage tank9to the combustion chamber7; and the stacked piston arrangement78is traveling towards BDC when the tank supply control valve13is opened to supply the air inlet port15in order to provide compressed air from the air storage tank9to the combustion chamber7.

In cases where engine power demand does not need an additional boost of air provided by the compressed air sent to air injection port15, the engine can operate in a normally aspirated manner, e.g. obtain air supply requirements for combustion of the fuel from the air inlet18using air obtained from ambient. In this manner, the set of stored instructions executed by the control system100would operate the stacked piston arrangement78during the first stroke of the two strokes of the power cycle as: positioning the tank supply control valve13as closed in order to inhibit the supply of compressed air into the inlet18via the air injection port15; wherein the internal combustion engine operates in a normally aspirated mode using ambient air collected via the inlet18. This mode can be used to charge the air storage tank9with compressed air, e.g. during engine idle, so that the air storage tank9can have compressed air of sufficient quantity for vehicle operations (e.g. operation of air brakes, operation of engine braking, air assisted engine starting, etc.). In this manner, the set of stored instructions executed by the control system100would operate the stacked piston arrangement78during multiple strokes of multiple power cycles as: positioning the tank supply control valve13as closed over a number of the power cycles in series in order to inhibit the supply of compressed air into the inlet15while increasing the air pressure in the air storage tank9; wherein the internal combustion engine operates in a normally aspirated mode using ambient air29collected via the inlet18.

If the control system100desires to vent the compression chamber8to ambient29rather than to direct the compressed air to the air storage tank9during travel of the piston1from BDC to TDC, the control system100would position the second port36to direct air with respect to the compression chamber8via the ambient control valve26coupled to ambient29, recognizing that the second port36can be separate from the first port86.

As discussed above, the provision of the independent air supply circuits82,84having different independent paths to ambient29for compressed air sourced from the air supply tank9(e.g. via the exhaust system62if exiting the combustion chamber7or via the control valves26,90if exiting the compression chamber8without entrance into the combustion chamber7) facilitates operation of air boost when demanded by the engine while at the same time providing for circumstances where the one or more ports76in the engine block20can direct air out of the compression chamber8while bypassing the exhaust system62by second port36for directing air with respect to the compression chamber8via the ambient control valve26coupled to ambient29. Alternatively, the one or more ports76in the engine block20can direct air out of the compression chamber8while bypassing the exhaust system62by the second port36being fluidly connected to the air storage tank9via the tank control valve35, such that air is circulated between the air storage tank9and the compression chamber8using the first port86and the second port36of air supply circuit84.

It is also recognized in the above that the stacked piston arrangement78can be incorporated into a four stroke power cycle, rather than the two stroke power cycle as provided by example. In this case, the combustion chamber7would experience an intake stroke, a compression stroke, a power stroke and an exhaust stroke in the four stroke power cycle. It should be recognized that during the four stroke power cycle, compression chamber8would be supplied by air (intake) during the intake stroke, would exhaust air (exhaust) during the compression stroke, would be again supplied by air (intake) during the power stroke, and would again exhaust air (exhaust) during the exhaust stroke, as the pistons1,2are coupled in reciprocation due to the supporting members4. The air supply circuit82could be used by the control system100to provide compressed air via tank supply control valve13to the air inlet port15for use in the intake stroke of the four stroke power cycle. It is recognized that the compression stroke and exhaust stroke would be used by the piston1to concurrently compress air and supply to the air storage tank9(via air port86and/or control valve35) and/or vent the air exhausted from the compression chamber8to ambient29(via air port36and control valve26and/or air port86and valve90). Similarly, the intake and power strokes of the four stroke power cycle would be used to draw air from ambient29(via port36) and/or from the air storage tank9(via port44).

For example, the stacked piston arrangement78can be operated by a control system100having the computer processor102and associated memory104programmed by a set of stored instructions106for executing the instructions106to operate in a power cycle using four strokes of the stacked piston arrangement78as: during a first stroke of the four strokes of the power cycle, the first stroke including travel of the stacked piston arrangement78from TDC to BDC: receiving via the position sensing system53a signal that the stacked piston78is adjacent to TDC; providing for inlet of air from ambient29into the compression chamber8; opening the tank supply control valve13to supply compressed air from the air storage tank9to the air inlet port15for injection into the combustion chamber7via the inlet18, the compressed air for use in mixing with fuel for facilitating combustion in the combustion chamber7during a second stroke of the power cycle; and during at least one of a second stroke and a fourth stroke of the power cycle, the second stroke and the fourth stroke including travel of the stacked piston arrangement from BDC to TDC: assessing if air pressure of the air storage tank9is above a pressure threshold, and if so then venting the air storage tank9; wherein exhaust contents present in the combustion chamber7are expelled from the combustion chamber7during the fourth stroke through operation of an exhaust valve23in the outlet19via the valve control system64.

Further, it is recognized that in the four stroke embodiment of the power cycle, the ambient control valve26can be opened to facilitate the venting. Further, when the stacked piston arrangement78can be traveling towards TDC when the tank supply control valve13is opened. Alternatively, the stacked piston arrangement78can be traveling towards BDC when the tank supply control valve13is opened. Also contemplated is the set of stored instructions106to operate in the power cycle during the first stroke of the four strokes of the power cycle as: positioning the tank supply control valve13as closed in order to inhibit the supply of compressed air into the inlet18; wherein the internal combustion engine operates in a normally aspirated mode using ambient air collected via the inlet18. Also contemplated is the set of stored instructions106to operate in the power cycle during at least one of the second stroke and the fourth stroke of the power cycle as: opening the ambient control valve26to direct the air out of the compression chamber8into ambient29rather than into the air storage tank9via the first port86. Further contemplated is the set of stored instructions106to operate in the power cycle as: positioning the tank supply control valve13as closed over a number of the power cycles in series in order to inhibit the supply of compressed air into the inlet18while increasing the air pressure in the air storage tank9; wherein the internal combustion engine operates in a normally aspirated mode using ambient air collected via the inlet18.

Further, as discussed above, the stacked piston arrangement78can be operated using air supply circuit82(e.g. for VCR applications) and/or can be operated using air supply circuit84(e.g. for engine braking or pneumatic operations). Provided below is an example of the stacked piston arrangement78in conjunction with using air supply circuit84

As noted above, the air supply circuit82can be optional and as such the air storage tank9could be dedicated for use in air supply circuit84having the compressed air storage tank9fluidly connected to the one or more ports76by the first supply line6for storing compressed air generated during operation of the internal combustion engine. The one or more ports76could include the first port86for directing compressed air from the compression chamber8to the air storage tank9, the first port86cooperating with the release port3positioned in the one or more supporting members4, wherein periodic alignment between first port86and the release port3during reciprocation of the second piston1provides for exhaust of compressed air out of the compression chamber8and into the air storage tank9. This described charging of the air storage tank9using compressed air contents from the compression chamber8can be done as part of two stroke or four stroke power cycle operation of the stacked piston arrangement78. The air supply circuit84could also have the one or more ports76include the second port36for directing air with respect to the compression chamber8via the ambient control valve26coupled to ambient29(e.g. for inlet of air from ambient29into the compression chamber8and/or exhaust of air from the compression chamber8into ambient29). It is also recognized that the second port36can be fluidly connected to the air storage tank9via the tank control valve35, thus providing for venting of the compression chamber8to tank9and/or the supply of compressed air from the tank9to the compression chamber8. It is also recognized that control valve41and supply line42can also be used to supply air port44with compressed air for inlet into the compression chamber8and/or for supply air port44with compressed air for exit from the compression chamber8and into the tank9.

Referring again toFIGS. 1,2 and 3, shown is the control system100having the computer processor102and associated memory104programmed by the set of stored instructions106for executing the instructions106to operate in a power cycle (e.g. two stroke, four stroke) using the stacked piston arrangement78. The control system100has the interface108for receiving and providing control signals110based on information110provided by the position sensing system53, the valve control system64, states of the various valves (e.g. valves5,13,26,32,35,41,43), and/or tank9pressure monitored by pressure sensor12.

In operation of the stacked piston arrangement78, during the power cycle, the stroke includes travel of the stacked piston arrangement78from TDC to BDC (seeFIG. 5), the control system100(seeFIG. 3) executes the instructions106to: receive via the position sensing system53a signal110that the stacked piston arrangement78is in position for travel towards BDC; open the tank control valve35to supply compressed air from the air storage tank9into the compression chamber8; and close the tank control valve35to inhibit the supply of compressed air into the compression chamber8during travel of the stacked piston arrangement towards TDC; wherein supply of compressed air in the first supply line6from the compression chamber8to the air storage tank9is inhibited by the outlet valve3positioned between the compression chamber8and the air storage tank9while air pressure introduced by the supply of compressed air into the compression chamber8biases travel of the stacked piston78arrangement towards BDC.

Further to the above, the control system100(seeFIG. 3) can execute the set of stored instructions106to operate the stacked piston arrangement78during the power cycle to: during travel of the stacked piston arrangement78from BDC to TDC (seeFIG. 4), optionally assess if air pressure of the air storage tank9is above a pressure threshold, and if so then vent the air storage tank9. The venting could involve opening the ambient control valve26,90to direct the air out of the compression chamber8into ambient29rather than into the air storage tank9. Another option is for the control system100to execute the set of stored instructions106to operate the stacked piston arrangement78during the power cycle to: position the tank control valve35as closed over a number of the power cycles in series in order to increase the air pressure in the air storage tank9.

As noted above, the exhaust system62coupled to the outlet19of the combustion chamber7is separate from the sir supply circuit84used to supply compressed air for engine start up assist. As such, the one or more ports76in the engine block20for directing air out of the compression chamber8bypasses the exhaust system62by the second port36for directing air with respect to the compression chamber8via the ambient control valve26coupled to ambient29. Further, the one or more ports76in the engine block20direct air out of the compression chamber8by bypassing the exhaust system62by the second port36,44fluidly connected to the air storage tank9via the control valve35,41, such that air is circulated between the air storage tank9and the compression chamber8using the first port86and the second port36,44.

Referring again toFIGS. 1, 2 and 3, shown is the control system100having the computer processor102and associated memory104programmed by the set of stored instructions106for executing the instructions106to operate in a power cycle (e.g. two stroke, four stroke) using the stacked piston arrangement78. The control system100has the interface108for receiving and providing control signals110based on information110provided by the position sensing system53, the valve control system64, states of the various valves (e.g. valves5,13,26,32,35,41,43), and/or tank9pressure monitored by pressure sensor12.

In operation of the stacked piston arrangement78, during the power cycle, the stroke including travel of the stacked piston arrangement78from BDC to TDC (seeFIG. 5) and return (seeFIG. 4), the control system100(seeFIG. 3) executes the instructions106to: receive via the position sensing system53a signal110that the stacked piston arrangement78is in position for travel towards BDC; open at least one of the control valve35,41,44and the ambient control valve26to supply air into the compression chamber8; and close the at least one of the control valve35,44and the ambient control valve26to inhibit egress of air from the compression chamber8during travel of the stacked piston arrangement towards TDC before reaching alignment of the release port3with the air outlet86; wherein the compression of air in the compression chamber8during travel of the stacked piston arrangement78towards TDC biases travel of the stacked piston arrangement78against travel towards TDC during operation of the combustion chamber7.

It is recognized that more aggressive braking of the stacked piston arrangement can be provided when compressed air from the air storage tank9is introduced to the compression chamber8during travel of the stacked piston arrangement78towards BDC, as compressed air (having an air pressure greater than ambient air when sourced from ambient29) is sourced from the air storage tank9via supply line(s)25,42with appropriate open/close of valves35,41,44during intake and compression of air with respect to the compression chamber8.

Alternatively, less-aggressive braking of the stacked piston arrangement can be provided when ambient air from ambient29is introduced to the compression chamber8during travel of the stacked piston arrangement78towards BDC, as ambient air (having an air pressure less than compressed air when sourced from air storage tank9) is sourced from ambient29via secondary port36with appropriate open/close of valve26during intake and compression of air with respect to the compression chamber8.

It is acknowledged that compressed air exiting the compression chamber8can be supplied (or resupplied) to the air storage tank9during exhaust of the compression chamber8, as desired, and/or can be vented to ambient29.

Further to the above, the control system100can execute the set of stored instructions106to operate the stacked piston arrangement78during the power cycle to: during travel of the stacked piston arrangement78from BDC to TDC, optionally assessing if air pressure of the air storage tank9is above a pressure threshold, and if so then venting the air storage tank9. The venting can be accomplished by opening the ambient control valve26to direct the air out of the compression chamber8into ambient rather than into the air storage tank9via the first port86when the stacked piston arrangement approaches TDC and the alignment of the release port3with the air outlet port86. Alternatively, the set of stored instructions can operate the stacked piston arrangement78during the power cycle to close the ambient control valve26to direct the air out of the compression chamber8and into the air storage tank9via the first port86rather than into ambient29when the stacked piston arrangement78approaches TDC.

In the alternative embodiment, in operation of the stacked piston arrangement78, during the power cycle, the stroke including travel of the stacked piston arrangement78from BDC to TDC (seeFIG. 5) and return (seeFIG. 4), the control system100(seeFIG. 3) executes the instructions106to: receive via the position sensing system53a signal110that the stacked piston arrangement78is in position for travel towards BDC; open at least one of the control valve35,41,44and the ambient control valve26to supply air into the compression chamber8; and retain opening of the at least one of the control valve35,44and the ambient control valve26to facilitate egress of air from the compression chamber8during travel of the stacked piston arrangement towards TDC before reaching alignment of the release port3with the air outlet86; wherein the compression of air in the compression chamber8during travel of the stacked piston arrangement78towards TDC biases travel of the stacked piston arrangement78against travel towards TDC during operation of the combustion chamber7.

As such, in the alternative embodiment, this can also be referred to as a form of non-aggressive braking whereby air (supplied from ambient29and/or from the air storage tank9) in compression chamber8undergoing compression is allowed to exit the compression chamber (e.g. via second port36,44) before alignment of the release port3and first outlet86during travel of the stacked piston arrangement78towards TDC.

As noted above, the exhaust system62coupled to the outlet19of the combustion chamber7is separate from the air supply circuit84(seeFIG. 3) used to supply compressed air for engine braking. As such, the one or more ports76in the engine block20for directing air out of the compression chamber8bypasses the exhaust system62by the one or more ports76including the second port36for directing air with respect to the compression chamber8via the ambient control valve26coupled to ambient29. Alternatively, the one or more ports76in the engine block20for directing air out of the compression chamber8bypasses the exhaust system62by the one or more ports76including the second port36,44fluidly connected to the air storage tank9via the valve35,43, such that air is circulated between the air storage tank9and the compression chamber8using the first port86and the second port36,44.

It is also recognized that if the supply of compressed air from the compression chamber8is not needed (e.g. the air storage tank9is full), the system100can be operated by the instructions106to cause: as piston1moves to BDC, air is drawn into the compression chamber8(e.g. via line45and check valve44and/or via second port36such as using valve26for air from ambient29). As piston1moves to TDC, air volume in the compression chamber8will be compressed according to valve35setting. During this condition, air in the compression chamber8is forced out past port36and controlled by valve26to ambient29, or, out past valve35, out past line25to tank9. Accordingly, using the second outlet36, piston1can begin to displace air volume from the instant it moves off BDC, therefore, resistance against piston1will be reduced during travel from BDC to TDC. It is also recognized that a combination of air exhausted from the compression chamber8to a variety of different sinks can be accommodated for in the context of a multi cylinder environment. For example, some of the cylinder exhausts (e.g. via outlets36,44,86) can be supplied to ambient29and/or directly to the air storage tank9during piston1travel while other cylinder exhaust(s) can be supplied to directly to the air storage tank9under compression (i.e. delaying exhaust from the compression chamber8) upon alignment of the release port3with outlet port86. This multi cylinder environment operation can be done via the control system100through appropriate selection of the number of cylinders storing (sending to the air storage tank9via either supply line6or supply line25,42) verses the number of cylinders venting to ambient via control valve26,90. Also, a driver could be able to select via input to the control system100how aggressive air storing is in relation to the preferred road speeds.