WO2023137587A1

WO2023137587A1 - Engine system and crankcase ventilation systems

Info

Publication number: WO2023137587A1
Application number: PCT/CN2022/072554
Authority: WO
Inventors: Lei Liu; Yuejin Xi; Navneet GAUTAM
Original assignee: Cummins Inc.
Priority date: 2022-01-18
Filing date: 2022-01-18
Publication date: 2023-07-27

Abstract

An engine system includes an engine, an intake manifold coupled to the engine, and a crankcase ventilation system coupled to the engine. The intake manifold includes a throttle valve disposed therein. The crankcase ventilation system includes a flow circuit system including a first inlet and a first outlet. The first inlet is fluidly coupled to the engine and is structured to receive blow-by from the engine. The first outlet is fluidly coupled to the intake manifold downstream from the throttle valve.

Description

ENGINE SYSTEM AND CRANKCASE VENTILATION SYSTEMS

TECHNICAL FIELD

The present disclosure generally relates to gas-liquid separation systems for internal combustion engine systems. More specifically, this disclosure relates to crankcase ventilation systems for separating oil from engine crankcase blow-by gases ( “blow-by” ) .

BACKGROUND

Internal combustion engine systems require oil for lubrication of moving parts. During engine operation, blow-by is generated from combustion gases that leak past the piston rings and into the engine crankcase. The blow-by in the engine crankcase includes pressurized gas that is laden with oil droplets (e.g., aerosol, etc. ) . This blow-by can pressurize the crankcase, increasing the risk particulate and gas emissions from the crankcase into the surrounding environment. The amount of blow-by generated by the engine system can depend on the arrangement of the crankcase ventilation system and may vary at different engine operating conditions (e.g., with changes in crankcase pressure) .

In some jurisdictions, emissions regulations have been implemented that prohibit the discharge of any gases from the engine crankcase and that limit the maximum pressure in the crankcase during operation of the engine system to at or below atmospheric pressure (e.g., NS6 emissions requirements of GB17691-2018) . Existing engine systems may include crankcase ventilation systems and devices to filter the oil droplets from the blow-by leaving the crankcase. These systems remove oil aerosol from the blow-by and return the separated oil to the engine crankcase. The separated blow-by-having a reduced amount of oil as compared to the blow-by from the crankcase-may be released into the atmosphere (e.g., in an open crankcase ventilation system) or returned to the engine system, for example, via an air inlet to the engine system (e.g., a closed crankcase ventilation system) . However, these systems may not maintain crankcase pressure below atmospheric pressure across the full range of engine operating conditions.

SUMMARY OF THE INVENTION

One embodiment of the present disclosure relates to an engine system. The engine system includes an engine, an intake manifold coupled to the engine, and a crankcase ventilation system coupled to the engine. The intake manifold includes a throttle valve disposed therein. The crankcase ventilation system includes a flow circuit system including a first inlet and a first outlet. The first inlet is fluidly coupled to the engine and is structured to receive blow-by from the engine. The first outlet is fluidly coupled to the intake manifold downstream from the throttle valve.

Another embodiment of the present disclosure relates to a crankcase ventilation system. The crankcase ventilation system includes a crankcase ventilation device, a first outlet conduit, and a second outlet conduit. The crankcase ventilation device includes a housing and a separator element. The housing includes a device first inlet port and a device outlet port. The separator element is disposed within the housing and is structured to separate oil from blow-by received from an engine system to produce a separated blow-by. The first outlet conduit is fluidly coupled to the device outlet port and is structured to direct the separated blow-by to a first location along an engine system. The second outlet conduit is fluidly coupled to the device outlet port and is structured to direct the separated blow-by to a second location along the engine system.

Yet another embodiment of the present disclosure relates to a an electronically-controlled flow control system for use with a crankcase ventilation system. The electronically-controlled flow control system includes an electronic flow control valve and a flow control unit that is communicably coupled to the electronic flow control valve. The flow control unit is structured to control the electronic flow control valve based on at least one of (i) a threshold pressure difference across the electronic flow control valve or (ii) an indication of an engine operating condition in combination with an indication of a crankcase pressure being above atmospheric pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several implementations in accordance with the disclosure and are therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings.

FIG. 1 is a schematic diagram of a crankcase ventilation system, according to an embodiment.

FIG. 2 is a side cross-sectional view of a crankcase ventilation device that can be used with the crankcase ventilation system of FIG. 1.

FIG. 3 is a side cross-sectional view of a check valve that can be used with the crankcase ventilation system of FIG. 1 and/or the crankcase ventilation device of FIG. 2.

FIG. 4 is a plot of engine crankcase pressure for an open crankcase ventilation system as a function of engine torque and operating speed, according to an embodiment.

FIG. 5 is a line graph of engine speed and engine crankcase pressure for a closed crankcase ventilation system as a function of time, according to an embodiment.

FIG. 6 is a plot of engine crankcase pressure for the engine system of FIG. 1 as a function of engine torque and operating speed, according to an embodiment.

FIG. 7 is a line graph of engine speed and engine crankcase pressure for the engine system of FIG. 1 as a function of time, according to an embodiment.

FIG. 8 is a line graph of engine speed and engine crankcase pressure associated with a first check valve structure that can be used with the crankcase ventilation system of FIG. 1, according to an embodiment.

FIG. 9 is a line graph of engine speed and differential pressure across the first check valve structure of FIG. 8 as a function of time, according to an embodiment.

FIG. 10 is a schematic diagram of a portion of a crankcase ventilation system, according to another embodiment.

FIG. 11 is a block diagram of a flow control unit that can be used with the crankcase ventilation system of FIG. 1 and/or FIG. 10.

FIG. 12 is a flow diagram of a method of controlling the crankcase ventilation system of FIG. 1 or FIG. 10.

Reference is made to the accompanying drawings throughout the following detailed description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative implementations described in the detailed description, drawings, and claims are not meant to be limiting. Other implementations may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and made part of this disclosure.

DETAILED DESCRIPTION

Embodiments described herein relate generally to crankcase ventilation systems and devices for internal combustion engine systems. The various concepts introduced above and discussed in greater detail below may be implemented in any of numerous ways, as the described concepts are not limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for illustrative purposes.

I. Overview

Embodiments of the present disclosure relate to a crankcase ventilation system that can eliminate the need for a separate compressor to maintain the crankcase at negative pressure (below atmospheric pressure) across the full range of engine operating conditions. The crankcase ventilation system includes a crankcase ventilation device and a jet pump that is structured to reduce the pressure in the crankcase device using flow of pressurized air from the intake manifold. The crankcase ventilation system can include two flow circuits extending from an outlet of the crankcase ventilation device. A first flow circuit extends from an outlet of the crankcase ventilation device to a location downstream from an intake valve in the intake manifold of the engine system. A second flow circuit extends from an outlet of the crankcase ventilation device to an inlet of a turbocharger for the engine system.

The crankcase ventilation system can further include a flow control valve (e.g., check valve, etc. ) that is structured to control the flow of gas leaving through the intake manifold. At high engine speed and/or load, the valve is structured so that a majority of the flow passes from the crankcase ventilation device into the turbocharger inlet. Under these conditions, the turbocharger operates at high speed and the pressure rise across the turbocharger may be greater than at engine idle conditions. Once the engine speed and/or load drops below a certain value, the valve is structured to switch to allow flow from the crankcase ventilation device to the intake manifold (downstream from the intake valve) , which is held at reduced pressure near engine idle conditions. In this way, negative pressure can be maintained within the crankcase regardless of the operating state of the turbocharger.

It should be appreciated that in some embodiments the crankcase ventilation system may include only the first flow circuit such that flow may be continuously directed to the location downstream from the intake valve in the intake manifold. Among other benefits, this would ensure negative pressure in the crankcase near engine idle conditions without requiring a separate flow control valve downstream from the crankcase ventilation device.

II. Example Crankcase Ventilation System

FIG. 1 shows a portion of an engine system 10, according to an embodiment. The engine system 10 includes an engine 12, an intake manifold 14, and a crankcase ventilation system 100. The intake manifold 14 is coupled to the engine 12. The intake manifold 14 has a throttle valve 22 disposed therein. The crankcase ventilation system 100 is coupled to the engine 12.

The engine system 10 can also include a valve cover 13 coupled to the engine 12 and a turbocharger 16 structured to deliver air 15 (e.g., filtered air, etc. ) to the engine 12 via the intake manifold 14. The turbocharger 16 includes an inlet 17. The engine 12 includes an engine block 18 (e.g., cylinder block, etc. ) and a crankcase 20 coupled to the engine block 18. The engine 12 may be a diesel engine, a gasoline engine, a natural gas engine, a dual fuel engine, a biodiesel engine, an E85 engine, a flex fuel engine, or another type of internal combustion engine or driver. The engine 12 may be used to power a truck, a boat, a locomotive, or another type of vehicle (e.g., an on-road or off-road vehicle) . In another embodiment, the engine 12 may be used to power an electric power generator (e.g., a genset, etc. ) . In yet another embodiment, the engine 12 may be used in an industrial application to power a pump, a hydraulic system, or another type of system.

As shown in FIG. 1, the engine block 18 defines a plurality of cylinders 19 for the engine 12. The engine block 18 is coupled to the crankcase 20. During operation, combustion gases may leak (e.g., blow) past the piston rings from the cylinders 19 and into the crankcase 20, generating blow-by 21 that can pressurize the crankcase 20. Over time, the blow-by 21-if not ventilated from the crankcase 20-can lead to engine oil leaks past crankshaft seals and other engine seals and gaskets. As shown in FIG. 1, the blow-by 21 is vented through a connection on the valve cover 13, which is coupled to an upper end of the engine block 18 and encloses an overhead valve system for the engine block 18. In another embodiment, the blow-by 21 may be vented from a connection on the crankcase 20 or another suitable location.

The intake manifold 14 is coupled to the engine block 18 and provides air 15 to the cylinders 19 in the engine block 18 during engine operation. The intake manifold 14 includes ducting (e.g., channels, etc. ) that route air 15 to the engine block 18 from other parts of an air intake system. The intake manifold 14 includes a manifold inlet 26 and a manifold outlet 28 downstream from the manifold inlet 26. The intake manifold 14 also includes an intake air throttle valve, shown as throttle valve 22, which is structured to control an amount of air 15 (e.g., from the turbocharger 16) into the intake manifold 14 and thereby regulate the pressure across the intake manifold 14. In the embodiment of FIG. 1, the throttle valve 22 is disposed at an intermediate position (e.g., approximately halfway) between the manifold inlet 26 and the manifold outlet 28. The throttle valve 22 may include a solenoid-controlled butterfly valve. In another embodiment, the throttle valve 22 may include a torque motor (e.g., direct drive) or another suitable driver.

As shown in FIG. 1, the air intake system may further include a charge air cooler 24 disposed upstream of the intake manifold 14 and structured to cool incoming air 15 from the turbocharger 16. The turbocharger 16 is disposed upstream from the charge air cooler 24 and is structured to compress incoming air 15 to improve engine power output. The turbocharger 16 may include a turbine-driven, forced-induction compressor that is driven by exhaust gases from the engine system 10. The turbocharger 16 includes an inlet 17 and an outlet 25 downstream from the inlet 17. The inlet 17 is coupled to an intake conduit 30 and is structured to receive air 15 from the intake conduit 30. The outlet 25 of the turbocharger 16 is fluidly coupled to the charge air cooler 24.

The crankcase ventilation system 100 is structured to separate gases from the blow-by 21 received from the engine 12 and return the separated fluids to the engine 12. The crankcase ventilation system 100 includes flow circuit system 150, having a combination of circuits, inlets, outlets, and conduits. As shown in FIG. 1, the crankcase ventilation system 100 includes a first inlet 127, a second inlet 152, and a first outlet 129 as the flow circuit system 150. In some embodiments, as shown in FIG. 1, the flow circuit system 150 also includes a second outlet 133. The first inlet 127 is fluidly coupled to the engine 12 and structured to receive blow-by 21 from the engine 12. The second inlet 152 is fluidly coupled to the intake manifold upstream from the throttle valve 22. The first outlet 129 is fluidly coupled to the intake manifold 14 downstream from the throttle valve 22. The second outlet 133 is fluidly coupled to the intake conduit 30.

Alternatively or additionally, the crankcase ventilation system 100 includes, as the flow circuit system 150, a first outlet conduit 130 and a second outlet conduit 134. The flow circuit system 150 may also include a second inlet conduit, shown as boost line 126. The first outlet conduit 130 is fluidly coupled to a crankcase ventilation device 102 and structured to direct separated blow-by 23 to a first location (e.g., the intake manifold 14 downstream from the throttle valve 22) along the engine system 10. The second outlet conduit 134 is fluidly coupled to the crankcase ventilation device 102 and structured to direct the separated blow-by 23 to a second location (e.g., the intake conduit 30) along the engine system 10.

The flow circuit system 150 can include a first flow circuit 128 and a second flow circuit 132, as described in more detail below. The

flow circuits

128, 132, and accordingly the flow circuit system 150, can include the first inlet 127, the second inlet 152, the second outlet 133, the first outlet 129, the first outlet conduit 130, the boost line 126, and the second outlet conduit 134. The first outlet conduit 130 connects to the second outlet conduit 134 at, for example, a first end 136 of the first outlet conduit 130.

The crankcase ventilation system 100 can also include a crankcase ventilation device 102 (e.g., gas-liquid separation assembly, breather, etc. ) . The crankcase ventilation device 102 is configured to couple to the flow circuit system 150 that routes blow-by 21 and separated fluids to/from the crankcase ventilation device 102. The crankcase ventilation device 102 is structured to separate liquid and gas from a fluid, such as a gas-liquid mixture, to produce separated blow-by 27 (e.g., gas with reduced oil content as compared to blow-by 21 from the engine 12) and liquid oil.

FIG. 2 shows an example of a crankcase ventilation device 102 that may be used with the crankcase ventilation system 100 of FIG. 1. The crankcase ventilation device 102 includes a main body, shown as housing 104, and a separator element 106. The crankcase ventilation device 102 can also include a jet pump 108. The jet pump 108 is coupled to the housing 104.

The housing 104 defines an interior cavity 110. The housing 104 includes a device first inlet port 112 and a device outlet port 118. The housing 104 may also define a device second inlet port 116 and a device drain 114. The device first inlet port 112 (e.g., blow-by inlet, etc. ) is structured to receive blow-by 21 from the engine 12 (see also FIG. 1) . The device drain 114 is structured to return separated liquid oil to the crankcase 20. The device second inlet port 116 is structured to receive air 15 from the intake manifold 14 (e.g., boost air, compressed air, etc. ) , and the device outlet port 118 (e.g., a filtered gas outlet, etc. ) is structured to exhaust a mixture of separated blow-by 27 and air 15 from the housing 104. As shown in FIG. 2, the housing 104 may be formed in multiple sections that correspond with different parts of the crankcase ventilation device 102. The sections may be welded (e.g., ultrasonically, spin-welded, etc. ) or otherwise coupled together to form a single component.

The separator element 106 is disposed within the housing 104, such as in the interior cavity 110. The separator element 106 is structured to separate liquid oil from blow-by 21 received from the engine 12 to produce separated blow-by 27. The separated blow-by 27 has a reduced oil content as compared to the blow-by 21. The separator element 106 may include a centrifugal separator, an inertial separator, or another gas-liquid separating device.

In the embodiment of FIG. 2, the separator element 106 includes a centrifugal pre-separator that is partially integrally formed with a lower section of the housing 104. Blow-by 21 enters the lower section tangentially to an outer perimeter of the housing 104 via the device first inlet port 112. Centripetal forces separate liquid oil (e.g., oil particles and aerosol) from the blow-by 21 to generate a partially separated blow-by that exits the lower section through an axially extending fluid conduit of the separator element 106. As shown in FIG. 2, the partially separated blow-by moves axially through the separator element 106 along a middle section (e.g., intermediate section, etc. ) of the housing 104 to an impactor separator 120 and pressure regulator at an upper end of the separator element 106. The partially separated blow-by is directed against the impactor separator 120, which separates additional oil from the fluid to produce the separated blow-by 27.

The jet pump 108 (e.g., boost pump, etc. ) is structured to reduce the pressure at an upper end of the interior cavity 110, to draw blow-by 21 out of the crankcase 20 and thereby maintain the crankcase 20 at negative pressure during engine operation. As used herein, “negative pressure” or “reduced pressure” refers to a pressure that is less than or equal to atmospheric pressure at a location where the engine 12 is operating (e.g., less than or equal to approximately 101.3 kPa at mean sea level, etc. ) . As shown in FIG. 1, the jet pump 108 is structured to use a flow of air 15 from the intake manifold 14 to reduce pressure at the upper end of the interior cavity 110. The jet pump 108 includes a pump outlet 154. The device outlet port 118 is disposed at the pump outlet 154.

The crankcase ventilation device 102 includes a nozzle 122 downstream of the device second inlet port 116. More specifically, and as shown in FIG. 2, the jet pump 108 includes the nozzle 122. The nozzle 122 is disposed downstream from and proximate to the device second inlet port 116. The nozzle 122 is positioned (e.g., oriented, etc. ) within the housing 104 to discharge gas toward the device outlet port 118. In the embodiment of FIG. 2, the nozzle 122 is positioned to discharge gas from the device second inlet port 116 toward a venturi element 124 that is disposed between the device second inlet port 116 and the device outlet port 118. The venturi element 124 includes a diverging section spaced apart from the nozzle 122 that reduces the velocity of gas exiting the housing 104.

During operation, the nozzle 122 increases the velocity of pressurized gas entering the jet pump 108 through the device second inlet port 116. The nozzle 122 also reduces the pressure of the gas at an outlet 156 of the nozzle 122 (see FIG. 2) , thereby reducing pressure at the upper end of the housing 104 in the space between the nozzle 122 and the venturi element 124.

The reduction in static pressure at the upper end of the interior cavity 110 of the housing 104 draws blow-by 21 through the separator element 106 and into the fluid stream entering the venturi element 124. The separated blow-by 27 then mixes with incoming air 15 at the upper end of the housing 104 where the mixture is exhausted out of the crankcase ventilation device 102.

As shown in FIG. 1, the crankcase ventilation system 100 is structured as a closed crankcase ventilation (CCV) system in which separated blow-by 27 is returned back to the engine 12 via the air intake system (e.g., the intake manifold 14) . As described above, the crankcase ventilation system 100 includes a blow-by inlet conduit 125 that fluidly couples the valve cover 13 to the device first inlet port 112 and that is structured to direct blow-by 21 from the engine 12 to the crankcase ventilation device 102. The crankcase ventilation system 100 also includes an inlet fluid conduit, shown as boost line 126, that directs air 15 (e.g., compressed air) from the intake manifold 14 to the crankcase ventilation device 102 to power the jet pump 108. As shown in FIG. 1, the inlet fluid conduit as the boost line 126 fluidly couples the device second inlet port 116 to the intake manifold 14 at a location upstream from the throttle valve 22.

In the embodiment of FIG. 1, the crankcase ventilation system 100 includes two

flow circuits

128, 132 in the flow circuit system 150. The two

flow circuits

128, 132 redirect the separated blow-by 27 from the crankcase ventilation device 102 to one of the inlet 17 of the turbocharger 16 or the intake manifold 14 downstream from the throttle valve 22.

A first flow circuit 128 of the crankcase ventilation system 100 is structured to direct (e.g., route, etc. ) separated blow-by 27 to a first location along the engine system 10, and a second flow circuit 132 is structured to direct separated blow-by 27 to a second location along the engine system 10 that is different from the first location. In the embodiment of FIG. 1, the first flow circuit 128 directs separated blow-by 27 from the crankcase ventilation device 102 (e.g., the device outlet port 118) to the first outlet 129 of the crankcase ventilation system 100. The first outlet 129 discharges separated blow-by 27 into the intake manifold 14.

As shown in FIG. 1, the first flow circuit 128 includes a first outlet conduit 130 (e.g., first outlet line, vacuum line, etc. ) that fluidly couples the crankcase ventilation device 102 (e.g., the device outlet port 118) to the intake manifold 14 at a location downstream from the throttle valve 22, at an intermediate position approximately half-way between the throttle valve 22 and the manifold outlet 28.

The second flow circuit 132 directs separated blow-by 27 from the crankcase ventilation device 102 to a second outlet 133 of the crankcase ventilation system 100. The second outlet 133 discharges the separated blow-by 27 into the inlet 17 of the turbocharger 16.

In the embodiment of FIG. 1, the second flow circuit 132 includes a second outlet conduit 134 (e.g., second outlet line, etc. ) that fluidly couples the device outlet port 118 to the intake conduit 30 upstream from the turbocharger 16 (e.g., upstream from the inlet 17 to the turbocharger 16, etc. ) . In the embodiment of FIG. 1, a first end 136 of the first outlet conduit 130 is fluidly coupled to the second outlet conduit 134 at a location proximate to the device outlet port 118. In another embodiment, this arrangement may be reversed.

In yet another embodiment, the first end 136 of the first outlet conduit 130 and a first end 155 of the second outlet conduit 134 may be fluidly coupled an intermediate conduit extending from the device outlet port 118. For example, the intermediate conduit may be a Y-Pipe or another conduit shape having a first end that is coupled to the device outlet port 118 and a second end that is coupled to both the first outlet conduit 130 and the second outlet conduit 134.

The crankcase ventilation system 100 also includes a flow control system 138 that is structured to control the flow of gas (e.g., separated blow-by 27) through the first flow circuit 128 and the second flow circuit 132 (e.g., to the first outlet 129 and the second outlet 133) . In a first mode of operation (e.g., first operating mode, etc. ) , the flow control system 138 is structured to direct the separated blow-by 27 to the second outlet 133 while blocking flow from passing through the first outlet 129 (e.g., to the second outlet 133 substantially independently from the first outlet 129) . In a second mode of operation (e.g., second operating mode, etc. ) , the flow control system 138 is structured to direct the separated blow-by 27 to the first outlet 129 (e.g., to the first outlet 129 substantially independently from the second outlet 133, but without blocking flow to the second outlet 133) .

The flow control system 138 may be structured to switch from the second mode of operation to the first mode of operation in response to an indication that the engine 12 is under low load and/or at near idle conditions. Under these conditions, a pressure rise across the turbocharger 16 may be less than a pressure drop across the throttle valve 22. The flow control system 138 may be structured to switch from the first mode of operation to the second mode of operation in response to an indication that the engine 12 is operating at high load and/or high speed conditions. At high load and/or speed, the increase in pressure rise across the turbocharger 16 provides greater motive force to the jet pump 108 to further reduce the pressure within the crankcase 20.

As shown in FIG. 1, the flow control system 138 includes a control valve 140 that is structured to switch the flow control system 138 between the first and second operating modes. In the embodiment of FIG. 1, the control valve 140 is disposed in the first outlet conduit 130, for example, between the crankcase ventilation device 102 and the intake manifold 14. The control valve 140 may include a spring-actuated check valve that prevents backflow of separated blow-by back toward the crankcase ventilation device 102. In other embodiments, the control valve 140 may include an electronically-actuated valve (e.g., a solenoid valve, etc. ) , such as the electronic flow control valve 202 shown in FIG. 10.

An example control valve 140 is shown in FIG. 3. The control valve 140 can be a check valve having a spring element 146 that is structured to open the check valve at a threshold pressure difference across the check valve. As shown, the control valve 140 includes an outer body 142 defining a passage; a plunger 144 disposed within and moveably engaged with the passage; and the spring element 146 biasing the plunger 144 against an interior ledge of the passage to selectively block fluid flow through the control valve 140. It should be appreciated that the design of the control valve 140 may be different in various embodiments. For example, the control valve 140 may include an electronically actuated solenoid valve or another valve type.

As shown in FIG. 1, the flow control system 138 also includes a check valve 148 disposed in the second outlet conduit 134, downstream from where the first outlet conduit 130 connects to the second outlet conduit 134. The check valve 148 may comprise any form of mechanical or electromechanical valve that prevents backflow through the second outlet conduit 134 so as to ensure that sufficient air 15 is supplied to the turbocharger at all times. In at least one embodiment, the check valve 148 has a low cracking pressure with negligible resistance to flow directed toward the inlet 17 of the turbocharger 16. Among other benefits, using a check valve 148 with low cracking pressure increases the total motive force available to draw blow-by 21 from the crankcase 20.

In the embodiment of FIG. 1, the flow control system 138 is structured to switch from the second operating mode to the first operating mode in response to a change in engine operating conditions (e.g., from a high load/speed engine operating condition to a low load/speed engine operating condition) and to prevent static pressure in the crankcase 20 from exceeding ambient pressure. In this way, the crankcase ventilation system 100 may adjust for changing operating conditions without requiring a supplemental compressor or pump to maintain the crankcase 20 at negative pressure across a full range of engine operating conditions (e.g., torques, speeds, loads, etc. ) for the engine system 10 and without reducing the efficiency of the engine 12 by requiring electronic and/or hydraulically powered compressors. The crankcase ventilation system 100 can also eliminate the need to route power and/or hydraulic fluid to a separate compressor to maintain the crankcase 20 at negative pressure.

The crankcase ventilation system 100 of the present disclosure has a number of advantages over alternative system designs. FIGS. 4–7 are plots of observed performance data from engine testing with various arrangements of the crankcase ventilation system 100. Referring to FIG. 4, a plot of engine crankcase pressure is shown across multiple engine operating conditions for an engine system that is equipped with an open crankcase ventilation system. Filled-in (e.g., closed) circles indicate positive (e.g., above ambient) crankcase pressure and unfilled (e.g., open) circles indicate negative (e.g., below ambient) crankcase pressure. Larger circles represent larger positive or negative pressures, respectively. The open crankcase ventilation is structured to vent separated blow-by gases from the engine to atmosphere instead of returning the separated blow-by back to the engine. As shown in FIG. 4, blow-by from the engine acts against the resistance of the crankcase ventilation system, resulting in positive crankcase pressure over the full operating range of the engine.

FIG. 5 shows a line graph of engine speed and crankcase pressure (relative to time elapsed) for a closed crankcase ventilation system that does not include a first flow circuit 128 (e.g., that only returns separated blow-by to the inlet of turbocharger for the engine system) . As shown, the turbocharger produces sufficient vacuum at high operating speeds to maintain negative pressure in the crankcase. However, at engine idle, the vacuum generated by the turbocharger (at the turbocharger inlet) is no longer sufficient to maintain the crankcase at negative pressure (e.g., the pressure rise across the turbocharger is very low) .

FIGS. 6 and 7 illustrate the performance of an engine system that is equipped with the crankcase ventilation system 100 of the present disclosure. As described with reference to FIG. 4, filled-in (e.g., closed) circles indicated positive values of crankcase pressure and unfilled (e.g., open) circles indicate negative values of crankcase pressure. Larger circles represent larger positive or negative pressures, respectively. As shown, in the second operating mode (e.g., at high engine operating torque and/or speed) the flow control system directs separated blow-by to the turbocharger inlet, similar to the arrangement described with reference to FIG. 5. However, as shown in FIG. 6, once the engine operating torque and/or speed are sufficiently reduced, the flow control system switches from the second operating mode to the first operating mode to redirect flow from the crankcase ventilation device to the first flow circuit 128. As shown in FIGS. 6 and 7, the pressure drop across the throttle valve at idle is sufficient to maintain the crankcase at negative pressure.

The maximum pressure experienced in the crankcase 20 during engine operation will depend, in part, on the cracking pressure of control valve 140. The cracking pressure is a pressure difference across the control valve 140 (e.g., between the device outlet port 118 and the intake manifold 14 downstream from the throttle valve 22) at which the control valve 140 opens (e.g., to allow detectable flow through the valve) . In the embodiment of FIG. 1, the cracking pressure of the control valve 140 depends on the design (e.g., spring load setting) of the spring element 146. The required spring load setting for the control valve 140 depends on operating characteristics of the engine 12. For example, FIGS. 8 and 9 show line graphs of observed crankcase pressure and pressure drop across a control valve 140 that is installed in an engine system. The spring load setting for the control valve 140 is set to provide a cracking pressure of less than or equal to approximately 20 kPa, which ensures that the crankcase remains at approximately negative pressure across a full range of engine operating conditions. It is noted that increasing the spring load setting for the spring element 146 may increase the maximum pressure in the crankcase at idle, while decreasing the spring load setting can result in reduced engine idle stability (due to excess bypass across the throttle valve) .

The design and arrangement of components described with reference to the embodiment of FIG. 1 should not be considered limiting. Many alternatives and combinations are possible without departing from the inventive concepts disclosed herein. For example, in some embodiments portions of the first flow circuit 128 and/or the second flow circuit 132 may be integrated with (e.g., built into) the crankcase ventilation device 102 (e.g., the control valve 140, a splitter between the first flow circuit 128 and the second flow circuit 132, etc. ) .

Referring to FIG. 10, an alternative engine system 34 is shown that is similar to the engine system 10 of FIG. 1 and includes at least some of the same components as the engine system 10 of FIG. 1. The engine system 34 includes a crankcase ventilation system 200 that includes an electronically-controlled flow control system 210. The crankcase ventilation system 200 is similar to the crankcase ventilation system 100 of FIG. 1 but includes an electronic flow control valve 202 (e.g., electrical solenoid valve, etc. ) in place of or in combination with a spring-actuated control valve 140.

The electronically-controlled flow control system 238 includes the electronic flow control valve 202 and a flow control unit 212. Accordingly, the crankcase ventilation system 200 includes the flow control unit 212 and a sensor system 240 that is used by the flow control unit 212 to control actuation of the electronic flow control valve 202.

As shown in FIG. 10, the sensor system 240 includes three separate pressure sensors each communicatively coupled to the flow control unit 212. More specifically, the sensor system 240 includes a first pressure sensor 204 (e.g., a first outlet pressure sensor, a downstream pressure sensor, etc. ) disposed in the intake manifold 14 at a location downstream from the throttle valve 22; a second pressure sensor 206 (e.g., crankcase pressure sensor) disposed in the valve cover 13; and a third pressure sensor 208 (e.g., an outlet pressure sensor, an upstream pressure sensor, etc. ) disposed proximate to the device outlet port 118. As such, the first pressure sensor 204 is structured to monitor and transmit an indication of static pressure downstream from the throttle valve 22 in the intake manifold. The second pressure sensor 206 is structured to monitor and transmit an indication of the static pressure in the crankcase 20. The third pressure sensor 208 is structured to monitor and transmit an indication of the static pressure at the device outlet port 118.

In an example embodiment, the first pressure sensor 204 is communicably coupled to the flow control unit 212 and is structured to transmit an indication of an intake manifold pressure of an intake manifold 14 to the flow control unit 212. The third pressure sensor 208 is communicably coupled to the flow control unit 212 and is structured to transmit an indication of a pressure upstream from the electronic flow control valve 202. The flow control unit 212 is structured to transmit a control signal to the electronic flow control valve 202 to open the electronic flow control valve 202 based on a difference between the intake manifold pressure and the pressure upstream from the electronic flow control valve 202.

In other embodiments, the number and/or location of the pressure sensors of the sensor system 240 may be different. For example, the second and

third pressure sensors

206, 208 may be replaced with a single differential pressure sensor arranged to directly measure a pressure drop across the electronic flow control valve 202. The crankcase ventilation system 200 may also be structured to receive data from various sensors for the engine system 10, such as sensors monitoring an operating speed of the engine 12 (e.g., engine speed sensor 209, and/or other sensors) .

Referring to FIG. 11, the flow control system 210 of the crankcase ventilation system 200 is shown. The flow control system 210 is structured to control operation of the electronic flow control valve 202 based on an operating condition of the engine system 34. The flow control system 210 includes an electronic control unit, shown as the flow control unit 212. The flow control unit 212 includes memory 214, a communications interface 216, and a processor 218. In other embodiments, the flow control unit 212 may include additional, fewer, and/or different components. In one embodiment, the flow control unit 212 is a standalone control unit of the crankcase ventilation system 200. In another embodiment, the flow control unit 212 is a control circuit (e.g., control module, etc. ) that forms part of an engine control unit for the engine system 34.

The memory 214 may be structured to store machine-readable instructions for the flow control unit 212. The machine-readable instructions may include instructions to monitor and store sensor data from one or more sensors of the engine system. Additionally, the machine-readable instructions may include instructions to determine an operating condition of the engine system 34, such as an operating condition of the engine 12, and control actuation of the electronic flow control valve 202 to maintain negative pressure in the crankcase 20. The memory 214 may also store threshold parameters for the

crankcase ventilation system

100, 200, such as a threshold pressure difference across the electronic flow control valve 202 at or above which the electronic flow control valve 202 should be opened.

The communications interface 216 is structured to interface the flow control unit 212 with other components of the crankcase ventilation system 200 and/or engine system. As shown in FIG. 11, the communications interface 216 is communicably coupled to the electronic flow control valve 202 and is structured to transmit signals (e.g., control signals) to control operation of the electronic flow control valve 202. The communications interface 216 is also communicably coupled to the sensor system 240, including the first pressure sensor 204, the second pressure sensor 206, the third pressure sensor 208, and the engine operating speed sensor. The communications interface 216 is structured to receive sensor data from the sensor system 240.

The communications interface 216 may include any type and any number of wired or wireless connections. For example, a wired connection may include a serial cable, a fiber optic cable, a CAT5 cable, or any other form of wired connection. Wireless connections may include the Internet, Wi-Fi, cellular, radio, Bluetooth, ZigBee, etc. In one embodiment, the flow control unit 212 forms part of a controller area network (CAN) bus for the engine system 34 that provides the exchange of signals, information, and/or data between vehicle components. The CAN bus includes any number of wired and wireless connections.

The processor 218 may be communicably coupled to each of the components of the flow control unit 212 and may be structured to control interaction between the components. For example, the processor 218 may be structured to control the collection, processing, and transmission of sensor data for the flow control unit 212. Additionally, the processor 218 may be structured to retrieve and interpret control parameters stored in the memory 214, and to control operation of the electronic flow control valve 202 based on the sensor data and control parameters.

Referring to FIG. 12, a flow diagram of a method 300 of controlling a crankcase ventilation system, such as the

crankcase ventilation system

100, 200, by a flow control system, such as the flow control system 210, is shown, according to an embodiment. As shown, the flow control system (e.g., flow control system 210 of FIG. 11) is structured to control the electronic flow control valve 202 based on (i) a threshold pressure difference across the electronic flow control valve 202 and/or (ii) an indication of an engine operating condition in combination with an indication of a crankcase pressure being above atmospheric pressure. An algorithm for controlling valve operation based on the pressure difference across the electronic flow control valve 202 is shown in branch 302. The flow control unit 212 receives an indication of intake manifold pressure from the first pressure sensor 204. The flow control unit 212 also receives an indication of CCV outlet pressure from the third pressure sensor 208 proximate to the device outlet port 118.

At 304, the flow control unit 212 determines a pressure difference between the intake manifold pressure and the CCV outlet pressure (e.g., the pressure upstream from the electronic flow control valve 202) , for example, by subtracting the CCV outlet pressure from the intake manifold pressure. At 306, the flow control unit 212 compares the pressure difference to a threshold pressure difference stored in memory (e.g., memory 214) . The flow control unit 212 (e.g., using the processor 218) is structured to transmit a control signal to the electronic flow control valve 202 to open the electronic flow control valve 202 based on a determination that the pressure difference satisfies (e.g., is greater than or equal to) the threshold pressure difference.

At the same time, the flow control unit 212 is structured to control the electronic flow control valve 202 based on the pressure in the crankcase 20 and the engine operating speed, as indicated by the algorithm shown in branch 308. For example, the flow control unit 212 may receive (e.g., periodically during engine operation) an indication of the pressure in the crankcase 20 from the second pressure sensor 206 and an indication of the engine speed from the engine speed sensor 209. The flow control unit 212 (e.g., using the processor 218) is structured to transmit a control signal to the electronic flow control valve 202 to open the electronic flow control valve 202 based on a determination that the engine 12 is operating (e.g., engine speed above 0 RPM, or at another suitable threshold) and an indication that the pressure in the crankcase 20 has risen above atmospheric pressure.

Among other benefits, the method 300 of FIG. 12 can improve system performance by ensuring that the electronic flow control valve 202 opens only when necessary to ensure the pressure in the crankcase 20 remains below atmospheric pressure, reducing the risk of engine stability at idle due to excessive bypass across the throttle valve 22 of the engine system 34.

III. Construction of Example Embodiments

It should be noted that the term “example” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples) .

As utilized herein, the term “substantially” and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed (e.g., within plus or minus five percent of a given angle or other value) are considered to be within the scope of the invention as recited in the appended claims.

The terms “coupled, ” “connected, ” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable) . Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.

While the term “processor” is briefly defined above, the term “processor” and “processing circuit” are meant to be broadly interpreted. In this regard and as mentioned above, the “processor” may be implemented as one or more general-purpose processors, application specific integrated circuits (ASICs) , field programmable gate arrays (FPGAs) , digital signal processors (DSPs) , or other suitable electronic data processing components structured to execute instructions provided by memory. The one or more processors may take the form of a single core processor, multi-core processor (e.g., a dual core processor, triple core processor, quad core processor, etc. ) , microprocessor, etc. In some embodiments, the one or more processors may be external to the apparatus, for example, the one or more processors may be a remote processor (e.g., a cloud based processor) . Alternatively, or additionally, the one or more processors may be internal and/or local to the apparatus. In this regard, a given circuit or components thereof may be disposed locally (e.g., as part of a local server, a local computing system, etc. ) or remotely (e.g., as part of a remote server such as a cloud based server) . To that end, a “circuit” as described herein may include components that are distributed across one or more locations.

It is important to note that the construction and arrangement of the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc. ) without materially departing from the novel teachings and advantages of the subject matter described herein. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the embodiments described herein.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any embodiment or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular embodiments. Certain features described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Claims

An engine system comprising:

an engine;

an intake manifold coupled to the engine, the intake manifold having a throttle valve disposed therein; and

a crankcase ventilation system coupled to the engine, the crankcase ventilation system including a flow circuit system comprising:

a first inlet fluidly coupled to the engine and structured to receive blow-by from the engine; and

a first outlet fluidly coupled to the intake manifold downstream from the throttle valve.
The engine system of claim 1, further comprising a turbocharger structured to direct air into the intake manifold, wherein the crankcase ventilation system further comprises a second outlet coupled to an inlet of the turbocharger.
The engine system of claim 1 or 2, wherein the crankcase ventilation system further comprises a crankcase ventilation device configured to separate oil from the blow-by received from the engine to produce separated blow-by,

wherein in a first operating mode, the crankcase ventilation system is structured to direct the separated blow-by to the second outlet while blocking the separated blow-by from passing through the first outlet, and

wherein in a second operating mode, the crankcase ventilation system is structured to direct the separated blow-by to the first outlet.
The engine system of any one of claims 1 to 3, wherein the crankcase ventilation system further comprises:

a crankcase ventilation device; and

wherein the flow circuit system further comprises:

a first outlet conduit that fluidly couples the crankcase ventilation device to the first outlet; and

a second outlet conduit that fluidly couples the crankcase ventilation device to a second outlet.
The engine system of any one of claims 1 to 4, wherein the crankcase ventilation system further comprises:

a second inlet that is fluidly coupled to the intake manifold upstream of the throttle valve; and

a crankcase ventilation device comprising a nozzle downstream of the second inlet.
The engine system of claim 5, wherein the crankcase ventilation system further includes a crankcase ventilation device comprising a jet pump disposed between the second inlet and the first outlet.
A crankcase ventilation system comprising:

a crankcase ventilation device comprising:

a housing that includes a device first inlet port and a device outlet port; and

a separator element disposed within the housing, the separator element structured to separate oil from blow-by received from an engine to produce a separated blow-by;

a first outlet conduit fluidly coupled to the device outlet port and structured to direct the separated blow-by to a first location along the engine system; and

a second outlet conduit fluidly coupled to the device outlet port and structured to direct the separated blow-by to a second location along the engine system.
The crankcase ventilation system of claim 7, wherein in a first operating mode, the separated blow-by is directed entirely to the second outlet conduit, and wherein in a second operating mode, the separated blow-by is directed at least partially to the first outlet conduit.
The crankcase ventilation system of claim 7 or 8, wherein the first location is a first outlet that is configured to discharge the separated blow-by into an intake manifold of the engine system, and wherein the second location is a second outlet that is structured to discharge the separated blow-by into an inlet of a turbocharger of the engine system.
The crankcase ventilation system of any one of claims 7 to 9, or the engine system of claim 4, wherein a first end of the first outlet conduit is fluidly coupled to the second outlet conduit.
The crankcase ventilation system of any one of claims claim 7 to 10, or the engine system of claim 4, wherein the crankcase ventilation system further comprises a flow control system including a check valve disposed in the second outlet conduit, the check valve structured to substantially prevent flow from passing through the check valve in a direction toward the first outlet conduit.
The crankcase ventilation system of any one of claims 8 to 11, or the engine system of claim 4 or 5, wherein the crankcase ventilation system further comprises a flow control system including a control valve disposed in the first outlet conduit, preferably wherein the control valve is a the check valve having a spring element that is structured to open the check valve at a threshold pressure difference across the check valve.
The crankcase ventilation system of any one of claims 7 to 12, or the engine system of any one of claims 1 to 7 wherein the crankcase ventilation system is structured to maintain a crankcase of the engine system at negative pressure across a full range of engine operating conditions for the engine system.
The crankcase ventilation system of any one of claims 7 to 13, wherein the housing further comprises a device second inlet port and the crankcase ventilation device comprises a nozzle downstream of the device second inlet port, the nozzle positioned to direct flow toward the device outlet port.
The crankcase ventilation system of any one of claims 7 to 14, wherein the crankcase ventilation device further includes a jet pump coupled to the housing, wherein the device outlet port is disposed at a pump outlet to the jet pump.
The crankcase ventilation system of any one of claims 7 to 15, or the engine system of any one of claims 1 to 6, further comprising a flow control system including:

an electronic flow control valve disposed in the first outlet conduit; and

a flow control unit communicably coupled to the electronic flow control valve, the control unit configured to open the electronic flow control valve in response to at least one of (i) a threshold pressure difference across the electronic flow control valve; or (ii) an indication of an engine operating condition in combination with an indication of a crankcase pressure being above atmospheric pressure.
An electronically-controlled flow control system for use with a crankcase ventilation system, the flow control system comprising:

an electronic flow control valve; and

a flow control unit communicably coupled to the electronic flow control valve, the flow control unit structured to control the electronic flow control valve based on at least one of (i) a threshold pressure difference across the electronic flow control valve; or (ii) an indication of an engine operating condition in combination with an indication of a crankcase pressure being above atmospheric pressure.
The flow control system of claim 17, further comprising a first pressure sensor communicably coupled to the flow control unit, the first pressure sensor structured to transmit an indication of an engine crankcase pressure to the flow control unit.
The flow control system of claim 17 or 18, further comprising at least one second pressure sensor communicably coupled to the flow control unit, the at least one second pressure sensor structured to transmit an indication of a pressure difference across the electronic flow control valve to the flow control unit.
The flow control system of any one of claims 17 to 19, further comprising:

a downstream pressure sensor communicably coupled to the flow control unit and structured to transmit an indication of an intake manifold pressure to the flow control unit; and

an upstream pressure sensor communicably coupled to the flow control unit and structured to transmit an indication of a pressure upstream from the electronic flow control valve, wherein the flow control unit is structured to transmit a control signal to the electronic flow control valve to open the electronic flow control valve based on a difference between the intake manifold pressure and the pressure upstream from the electronic flow control valve.