Abstract: Methods and systems are provided for a fuel supply system for an internal combustion engine system, in particular of a motor vehicle, having at least one liquefied petroleum gas (LPG) tank for storing an LPG fuel and at least one direct injection unit, which has a direct injection fuel distributor and direct injection valves that can be supplied with fuel via said distributor. In order to improve supply of the internal combustion engine system with LPG fuel, the fuel supply system includes a booster pump inserted between the LPG tank and the direct injection fuel distributor. A discharge side of the booster pump is connected directly to the direct injection fuel distributor by at least one line, and the direct injection valves each have a closure part that rises outward from a valve seat to open the respective direct injection valve.

Abstract: A fuel property determining device for an engine is provided, the device retarding a fuel injection timing and determining a fuel property based on a combustion variation of the engine caused by the retarding. The device includes a processor configured to control a parameter related to combustibility so as to degrade a combustion state before the fuel injection timing is retarded, the parameter being different from the fuel injection timing.

Abstract: An internal combustion engine is described. Controlling the internal combustion engine includes gathering engine operating data during steady-state engine operation, including gathering a first dataset associated with a cylinder air charge during steady-state operation of the engine in the PVO state and gathering a second dataset associated with a cylinder air charge during steady-state operation of the engine in the NVO state. An optimization routine is executed to determine a first subset of parameters associated with a first relationship for a cylinder air charge model based upon the second dataset. The optimization routine is also executed to determine a second subset of parameters associated with a second relationship for the cylinder air charge model based upon the first dataset. A cylinder air charge is determined in real-time during engine operation based upon the cylinder air charge model and the first and second subsets of parameters.

Abstract: An engine system having an ERG apparatus may include an engine including a plurality of combustion chambers generating a driving torque by combustion of a fuel; an intake line inflowing an intake gas supplied to the combustion chamber; an exhaust line flowing an exhaust gas exhausted from the combustion chamber; a turbocharger including a turbine provided at the exhaust line and rotated by the exhaust gas exhausted from the combustion chamber and a compressor provided at the intake line, rotated in connection with the turbine, and compressing external air; and an EGR apparatus including a recirculation line branched from the exhaust line and joined to the intake line, a flow rate controller mounted at the recirculation line and measuring and controlling an amount of recirculation gas, and a pressure sensor mounted at the recirculation line to measure a pressure of the recirculation gas.

Abstract: Synergistic induction and turbocharging includes the use of one or more throttles in close proximity to each cylinder intake valve to control air flow in each intake port delivering air to combustion cylinders in an internal combustion engine system. A turbocharger may also be affixed in close proximity to each cylinder exhaust valve to enable a synergistic combination of hyper-filling cylinders with combustion air and immediate harvesting of exhaust gas by adjacent turbochargers. In some implementations the turbochargers may be low-inertia turbochargers. The combination of individual throttles per intake port and a turbocharger in close proximity to each cylinder enables faster ramp-up of an engine in the early stages of acceleration. Various implementations thus provide improved fuel economy and improved engine performance in tandem, instead of one at the expense of the other.

Abstract: A method to control engine stop-start in a vehicle is provided. The method includes a controller outputting an engine command to auto-start an engine based on detection of shifter position change to one of a first set of shifter positions and whether a first predetermined time threshold has expired following the shifter position change in response to presence of an engine auto-stop mode and one of a set of preselected drive modes. The vehicle may include an engine, a traction battery, and a controller. The traction battery selectively powers components of the vehicle when the engine is auto-stopped. The controller is programmed to, in response to detecting an engine auto-stop condition, one of a set of preselected drive modes, and a shifter position change to one of a first set of shifter positions with a brake application, output an engine command to engage engine auto-start.

Abstract: Various methods and systems are provided for a thermal management system of an engine. A method for an engine may comprise adjusting an engine speed during an engine start event that includes an engine cranking activity from a first engine speed to a second engine speed, where the adjusting is based on a sensed oil temperature; adjusting a first resistance of a radiator primary return line of a thermal management system to a first resistance level; and adjusting the engine speed a duration after a start of the engine cranking from the second engine speed to a third engine speed, the third engine speed based at least in part on an engine torque demand, and selectively adjusting the first resistance between each of the first resistance level and a second resistance level based on the third engine speed, the second resistance level being lower than the first resistance level.

Abstract: An engine idling control method for a construction machine includes setting, by an E-ECU, an initial engine RPM as a starting mode (S mode) by receiving a signal from a V-ECU at the time of an engine startup; receiving, by the E-ECU, a first instruction via an engine speed control switch in a state other than an automatic idle mode; activating the automatic idle mode when the first instruction is not input to a machine during a certain time period, and setting the engine RPM as the starting mode (S mode); deactivating the automatic idle mode when a second instruction is input to the machine via the engine speed control switch while the automatic idle mode is activated; and calculating, by the V-ECU, an actual torque required for a pump for starting the machine according to the second instruction when the automatic idle mode is deactivated, and sending the actual torque to the E-ECU.

Abstract: In cases where a control device determines that a load is continuously less than a predetermined value for a predetermined period, the control device executes a first control to maintain the engine speed at a first rotation speed or higher, and when the control device determines that the load reached the predetermined value within the predetermined time, the control device executes a second control to maintain the engine speed at a second rotation speed or higher, which is higher than the first rotation speed. This provides a control device for an engine and an engine, which can restrain activation of an oil pressure switch attributed to an oil temperature.

Abstract: Systems and methods for determining fuel delay in a fuel injected engine with cylinders that may be deactivated are presented. In one example, the fuel injection delay is determined via a cylinder firing schedule array when the cylinder firing schedule array is available. The fuel injection delay is determined via weighted average of a fuel injection delay of a present engine cycle and a fuel injection delay of a past engine cycle when the cylinder firing schedule array is not available.

Abstract: Systems and methods for operating an engine operated by a controller that has a capacity to determine whether or not misfire occurs in the engine are presented. In one example, an operating region of the engine is broken into a plurality of zones and a misfire threshold level is dynamically provided for each of the plurality of zones based on slowly updated zone-level statistical parameters and quickly updated buffer-level parameters. The real-time dynamic misfire thresholds provide a basis for determining misfire within the engine.

Abstract: There is provided fuel-system failure detection apparatus applied to an engine capable of switching between a first injection mode and a second injection mode, which comprises a first failure determination unit which performs a fuel system failure determination process while the engine is operating in the first and the second injection modes, respectively, a second failure determination unit which, when the first failure determination unit gives a decision of failure while the engine is operating in either of the two injection modes, performs the fuel system failure determination process while the engine is operating in the other injection mode, and a failure identification unit which identifies a failure in fuel systems governing the first and second injection modes respectively, based on a decision about failure given by the second failure determination unit.

Abstract: Disclosed herein is a method for diagnosing and controlling a two-step exhaust variable valve lift (VVL) system, including: a controlling device acquiring an operation state signal of a vehicle; when the vehicle is in the over-run state, the controlling device outputting a mode conversion signal of the two-step exhaust VVL system; an air mass sensor measuring an air mass entering an engine, and the controlling device comparing a predetermined prediction value of the air mass with the measured air mass; when a difference of the compared air mass corresponds to a predetermined mode conversion comparing amount, the controlling device determining that a mode conversion of the two-step exhaust VVL system is completed; and when the difference of the compared air mass does not correspond to the mode conversion comparing amount, the controlling device determining that the two-step exhaust VVL system is faulty and outputting a result thereof.

Abstract: A method for monitoring an exhaust-gas sensor in which it is determined whether at least one monitored event has occurred by evaluating at least one heat quantity supplied to and/or withdrawn from the exhaust-gas sensor during a period of time, in particular under consideration of a change in the heat quantity stored by the exhaust-gas sensor that occurs during the period of time.

Abstract: A method of controlling a fuel injection quantity using a lambda sensor may include performing a lambda deviation learning mode by controlling a lambda deviation, due to a difference between a lambda model value and a lambda sensor measurement value, by a controller during engine combustion in which an engine RPM and a fuel injection quantity are detected, wherein, in the lambda deviation learning mode, a learning map is learned and is then updated by setting a fuel correction quantity depending on the lambda deviation as a learning value, and a fuel injection quantity is determined, in consideration of the fuel correction quantity depending on an RPM and a fuel quantity based on the updated learning map, and is output as an output value, so that the output value is applied to feedback control for a next fuel injection quantity.

Abstract: A semiconductor device has a peak value storage register, a threshold value storage register, a peak determination circuit, and an end timing determination circuit. The peak determination circuit determines whether or not to update a value stored in the peak value storage register. Further, the peak determination circuit ends an operation if the end timing determination circuit determines that an end timing has arrived. The peak value storage register updates a storage value if the peak determination circuit determines to perform updating. The end timing determination circuit determines that the end timing of the operation of the peak determination circuit has arrived if the value of an input signal becomes smaller than a value obtained by decreasing or increasing the value stored in the peak value storage register by a value corresponding to a threshold value stored in the threshold value storage register.

Abstract: A control device of an internal combustion engine includes an estimating means adapted to estimate an amount of a mixture of fuel and oil dispersing according to a movement of a piston within a cylinder; and a limiting means adapted to limit an upper limit torque (UT) of an internal combustion engine according to the estimated amount of the mixture.

Abstract: A fuel property determining device for an engine is provided, which retards a fuel injection timing and determines a fuel property based on a combustion variation of the engine caused by the retarding. The device includes a first determining module for setting a retarding amount to a first setting amount at an early stage of the fuel property determination, and in a case where the variation is above a first given value when the first amount is set, suspending the retarding and determining that the fuel property is a first fuel property, and a second determining module for setting the retarding amount to a second setting amount in a case where the variation is below the first given value when the first amount is set, and determining the fuel property based on the variation caused when the second amount is set, the second amount being larger than the first amount.

Abstract: A fuel injection valve (6) is configured such that the effective opening area of an injection port (61) increases as its lift amount increases. A fuel injection control unit (an engine control unit 100) injects fuel in a lift amount changing mode wherein, when fuel is injected into a combustion chamber (17) in the terminal period of the compression stroke, the lift amount of the fuel injection valve is set to a predetermined large lift amount in the earlier period of the injection period, and in the later period of the injection period following the earlier period of the injection period, the lift amount is set to a small lift amount smaller than the large lift amount and is in a range where the fuel injection speed increases.

Abstract: Various methods and systems are provided for diagnosing a condition of a fuel injector of an engine. In one example, a method for an engine includes injecting a first pulse of fuel as a first pilot injection into a first subset of cylinders of a plurality of engine cylinders, where the first pilot injection precedes a primary injection of fuel into the first subset of cylinders by a duration; correlating a first response in an engine operating parameter to the first pilot injection; and adjusting the primary injection of fuel into the first subset of cylinders based on the first response. In one example, the first pilot injection precedes the primary injection by a predefined short duration and the primary injection of fuel is adjusted within a predefined or preset upper limit and lower limit.

Abstract: A cylinder liner for an opposed-piston engine, and corresponding methods of extending engine durability and thermal management therewith, has opposite ends and a bore with a longitudinal axis for supporting reciprocating movement of a pair of opposed pistons. An intermediate portion of the liner extends between the opposite ends and includes an annular liner portion within which the pistons reach respective TC locations. A liner ring is seated in a portion of the bore in the annular liner portion, between the TC locations, for scraping carbon from top lands of the pistons and/or increasing the thermal resistance of the annular liner portion.

Abstract: A cylinder block is provided with a cylinder bore wall section configured to support a piston which reciprocates in a cylinder bore. The cylinder bore wall section includes a hollow portion at a location of the cylinder bore wall section on the side away from a cylinder head in the cylinder axial direction. The width of the hollow portion in the cylinder radial direction is greater on the side away from the cylinder head in the cylinder axial direction than the side closer to the cylinder head.

Abstract: A cylinder block of an internal combustion engine includes a cylinder bore wall that holds a piston so as to allow the piston to reciprocate. In at least one part of the cylinder bore wall in a cylinder axial direction, the density of a layer located farther from a cylinder head is lower than the density of a layer located closer to the cylinder head in the cylinder axial direction.

Abstract: A piston for an internal combustion engine includes a piston crown having a combustion bowl formed therein, a piston rim extending circumferentially around the combustion bowl and a heat-dissipating chamfer between the combustion bowl and the piston rim. The chamfer is structured by way of at least one of size, angle, or material thickness to an oil gallery to balance heat dissipation with combustion properties. Related methodology is disclosed.

Abstract: A thrust reverser system for a gas turbine engine includes a support structure, a transcowl, an actuator, and a retractable cable. The support structure is configured to be mounted to the turbine engine. The transcowl is mounted on the support structure and is axially translatable, relative to the support structure, between a stowed position and a deployed position. The actuator is configured to supply an actuation force to the transcowl to thereby move the transcowl between the stowed and deployed positions. The retractable cable is coupled to the transcowl and the support structure, and is configured to react reverse thrust loads on the transcowl at least when the transcowl is in the deployed position, to thereby at least reduce thrust loading on the actuator.

Abstract: A blocker door assembly for use in a gas turbine engine includes a facesheet including a plurality of openings to facilitate noise attenuation and a body portion coupled to the facesheet. The body portion includes a backsheet integrally formed with a honeycomb core, wherein the body portion is molded from a thermoplastic material.

Abstract: A thrust reverser system for a gas turbine engine includes a support structure, a transcowl, an actuator, and a hydraulic assist mechanism. The actuator is configured to supply an actuation force to the transcowl to thereby move the transcowl between the stowed and deployed positions. The hydraulic assist mechanism is coupled to the transcowl and is configured to react reverse thrust loads on the transcowl at least when the transcowl is translating between the stowed position and the deployed position.

Abstract: A gas turbine engine includes a spool configured to rotate about an axial centerline. The spool includes a fan rotor and a cold turbine rotor. The fan rotor is rotatably driven by the cold turbine rotor. A cold turbine inlet passage is configured to direct an airflow along a radial inward trajectory to the cold turbine rotor.

Abstract: An actuator produces a displacement that maintains positive contact between an electrically operated propellant and a pair of electrodes to ignite and sustain combustion of an ignition surface. The electrodes are suitably configured such that current lines between the electrodes follow equipotential surfaces through the propellant. The displacement drives a contour of the ignition surface to substantially match an equipotential surface corresponding to a maximum and uniform current density J at a minimum gap between the electrodes to ignite and combust the entire ignition surface. The flat, angled or curved contact areas of the electrodes are suitably symmetric about a plane.

Abstract: After filling a tank (18) with liquid oxygen (20) that is to be used to feed a rocket engine (10) with oxidizer, but prior to causing the engine (10) to operate, the tank is pressurized by injecting gaseous nitrogen (N) into the tank. While the engine (10) is in operation, liquid oxygen (20) is taken off, the taken-off oxygen is heated so as to obtain gaseous oxygen, and the gaseous oxygen is injected into the gas blanket (42) of the tank, with the pre-pressurization nitrogen forming a nitrogen buffer (40) between the liquid oxygen present in the gaseous oxygen tank injected into the gas blanket.

Abstract: A check valve that can prevent sticking of a valve body and reliably perform an opening and closing action in a check vale having a simple structure and that does not use biasing means on the valve body. A check valve has support pieces of a valve body protruding in the valve body direction on a circular base seat forming an outflow window in the center inserted in a circular groove where a support member (retainer) is formed between an outflow opening and a valve seat and on an open edge of the outflow window formed in the center of the base seat, and the support pieces of the support member (retainer) that support the valve body have linear or planar support parts on the top portion for leveling at least in a radial direction of the base seat.

Abstract: A feedstock delivery system transfers a carbonaceous material, such as municipal solid waste, into a product gas generation system. The feedstock delivery system includes a splitter for splitting bulk carbonaceous material into a plurality of carbonaceous material streams. Each stream is processed using a weighing system for gauging the quantity of carbonaceous material, a densification system for forming plugs of carbonaceous material, a de-densification system for breaking up the plugs of carbonaceous material, and a gas and carbonaceous material mixing system for forming a carbonaceous material and gas mixture. A pressure of the mixing gas is reduced prior to mixing with the carbonaceous material, and the carbonaceous material to gas weight ratio is monitored. A transport assembly conveys the carbonaceous material and gas mixture to a first reactor where at least the carbonaceous material within the mixture is subject to thermochemical reactions to form the product gas.

Abstract: A feedstock delivery system transfers a carbonaceous material, such as municipal solid waste, into a product gas generation system. The feedstock delivery system includes a splitter for splitting bulk carbonaceous material into a plurality of carbonaceous material streams. Each stream is processed using a weighing system for gauging the quantity of carbonaceous material, a densification system for forming plugs of carbonaceous material, a de-densification system for breaking up the plugs of carbonaceous material, and a gas and carbonaceous material mixing system for forming a carbonaceous material and gas mixture. A pressure of the mixing gas is reduced prior to mixing with the carbonaceous material, and the carbonaceous material to gas weight ratio is monitored. A transport assembly conveys the carbonaceous material and gas mixture to a first reactor where at least the carbonaceous material within the mixture is subject to thermochemical reactions to form the product gas.

Abstract: A feedstock delivery system transfers a carbonaceous material, such as municipal solid waste, into a product gas generation system. The feedstock delivery system includes a splitter for splitting bulk carbonaceous material into a plurality of carbonaceous material streams. Each stream is processed using a weighing system for gauging the quantity of carbonaceous material, a densification system for forming plugs of carbonaceous material, a de-densification system for breaking up the plugs of carbonaceous material, and a gas and carbonaceous material mixing system for forming a carbonaceous material and gas mixture. A pressure of the mixing gas is reduced prior to mixing with the carbonaceous material, and the carbonaceous material to gas weight ratio is monitored. A transport assembly conveys the carbonaceous material and gas mixture to a first reactor where at least the carbonaceous material within the mixture is subject to thermochemical reactions to form the product gas.

Abstract: A homogeneous charge compression ignition engine includes a cylinder configured to accommodate a piston to be reciprocally movable, a fuel injection valve configured to inject fuel into the cylinder, a water injection valve configured to inject water into the cylinder, a fuel injection control module configured to inject fuel from the fuel injection valve into the cylinder at such a timing that a mixture of fuel and air is self-ignited in a latter stage of a compression stroke or in an initial stage of an expansion stroke, and a water injection control module configured to perform at least a basic water injection of injecting water from the water injection valve into the cylinder during a predetermined period, which starts concurrently with or after start of combustion by the self-ignition and which overlaps a combustion period.

Abstract: Methods and systems are provided for conducting a canister purging operation and for rationalizing components of a vehicle evaporative emission system. In one example, after completion of a refueling event, a first fuel vapor canister purge operation is conducted to desorb hydrocarbon light ends from the fuel vapor canister, and subsequently the canister is heated to desorb hydrocarbon heavy ends from the canister, which are routed to a hydrocarbon sensor to rationalize the hydrocarbon sensor, before being purged to engine intake in a second purging operation. In this way, a fuel vapor storage canister may be thoroughly cleaned of hydrocarbon light ends and hydrocarbon heavy ends, while additionally indicating whether a canister heating element, and a hydrocarbon sensor positioned between the canister and atmosphere, are functioning as desired.

Abstract: A fuel vapor purge system may include a recirculation line that is branched from an intake line that supplies intake air to an engine to join to the intake line of the rear end portion of a compressor of a turbocharger; an ejector that is integrally formed with a recirculation valve housing that is disposed at a point in which the recirculation line and the intake line join; a first purge line that connects a canister and the intake line; and a second purge line that connects the canister and the ejector.

Abstract: Methods and systems are provided for processing of an on-board diagnostic (OBD) test dataset, and transferring parameters of a curve fit to the processed data to an off-board location. In one example, a method may include performing an evaporative emissions system diagnostic test, fitting a curve to at least a part of the data, transferring parameters of the curve fit, along with the start, and end data points to an off-board location for further processing. The on-board controller may adjust engine operating conditions based on signal received from the off-board location after off-board data reconstruction, and analysis.

Abstract: The present invention is related to an optimization method to internal combustion engines that reduces the fuel consumption and the exhaust emissions and particulated material. The operation principle is based in the introduction of small quantities of hydrogen in the air intake duct of the engine with the objective of optimizing the combustion of the traditional fuels, improving the parameters of the combustion reaction. This optimized combustion will increase the efficiency of the engine and reduce its environmental impact. The hydrogen is produced by an electrolysis reaction inside an electrochemical closed cell with non-circulating electrolyte.

Abstract: Methods and systems are provided for a mixer. In one example, a system may include an EGR mixing having a downstream surface with a plurality of venturi tubes extending therefrom.

Abstract: An Exhaust Gas Recirculation (EGR) cooler assembly and an EGR cooler conduit assembly are provided. Heat exchange tubes in EGR cooler assemblies may vibrate and contact the EGR cooler shell, thereby leading to the tube fretting and potentially failing. The current disclosure is directed to the use of damping rods to absorb vibratory impacts and reduce or eliminate tube fretting.

Abstract: A cylinder head casting for a three cylinder engine having a dedicated exhaust gas recirculation cylinder and two non-dedicated cylinders, includes three combustion chamber upper wall portions. First and second exhaust ports/runners extend from two of the three combustion chamber upper wall portions, respectively, for the non-dedicated cylinders and are paired together prior to a first common breakout at an exhaust flange in a side face of the cylinder head. A third exhaust port/runner extends from the other of the three combustion chamber upper wall portions corresponding to the dedicated EGR cylinder remains separated from the first and second exhaust port runners until a separate second breakout at the exhaust flange.

Abstract: Methods and systems for operating an engine including an external exhaust gas recirculation (EGR) system are presented. In one non-limiting example, output of a differential pressure sensor and output of an intake manifold pressure sensor are used as a basis for determining whether or not EGR system degradation is present while an engine is operating at conditions other than engine idle conditions.

Abstract: A fuel-saving device for treating a fuel includes at least one pyroelectric element to be in contact with the fuel. The at least one pyroelectric element includes a high molecular polymer substrate and a plurality of polarized pyroelectric particles dispersed in the polymer substrate. The polarized pyroelectric particle has infrared absorption peaks at wavenumber ranging from 430 cm?1 to 980 cm?and from 1600 cm?to 2700 cm?1.

Abstract: A combustion assist device is provided in an internal combustion engine provided with a fuel injector for injecting at least a portion of fuel into an intake manifold. Further, the combustion assist device is provided with an electrode element which is provided in the intake manifold and to which a high frequency high voltage is applied. The electrode element includes a dielectric material plate, a first metal conductor, and a second metal conductor. The dielectric material plate includes a first surface and a second surface, and divides a portion of the intake manifold into a first flow path on a first surface side and a second flow path on a second surface side. The first metal conductor is provided on the first surface. The second metal conductor is provided on the second surface.

Abstract: A fuel system includes a cooling fuel supply line that conveys a flow of cooling fuel from a storage tank to a mixing device. An upstream fuel return line conveys a flow of heated fuel to the mixing device from an internal combustion engine. The flow of the heated fuel from the upstream fuel return line mixes with the flow of cooling fuel from the cooling fuel supply line in the mixing device to form a flow of mixed fuel. A downstream fuel return line conveys the flow of mixed fuel from the mixing device to the storage tank. The mixing device includes a flow restrictor operable to generate a low pressure zone relative to a fluid pressure of the flow of cooling fuel in the cooling fuel return line that draws the flow of the cooling fuel through the cooling fuel supply line and into the mixing device.

Abstract: An intake system component of an internal combustion engine includes a porous material product and a resin molded portion. The porous material product is formed from a porous material and includes an outer edge and a general portion. The resin molded portion encompasses the outer edge and is formed integrally with the porous material product. The general portion is located outside the resin molded portion. The outer edge has a lower filling density than the general portion.

Abstract: An air cleaner has a first housing having an inlet and an upper opening, a second housing having an outlet and a lower opening, a filter element arranged between the upper opening of the first housing and the lower opening of the second housing. The first housing includes a looped wall, which protrudes from the inner surface thereof, and a vibrating body, which is made of a non-air permeable material and fixed to the upper end of the looped wall. Inside the first housing, an air chamber is defined by the inner surface of the bottom wall, the inner peripheral surface of the looped wall, and the lower surface of the vibrating body.

Abstract: An air cleaner has a first housing having an inlet and an upper opening, a second housing having an outlet and a lower opening, a filter element arranged between the upper opening of the first housing and the lower opening of the second housing. The first housing includes a looped wall, which protrudes from the inner surface thereof, and a sound absorbing member, which is made of an air permeable material and fixed to the upper end of the looped wall. The inner surface of the first housing, the inner peripheral surface of the looped wall, and the sound absorbing member define an air chamber.

Abstract: A positive crankcase ventilation system for an internal combustion engine routes blowby gases into the intake of the engine. Because the blowby gases have about 12% water vapor, during cold-weather operation, the water vapor may freeze in the PCV valve or in the port that couples the PCV duct with the intake manifold. In situations in which the PCV duct is pointing toward the direction of flow of the intake gases, a hood or cap is placed over the end of the tube according to the present disclosure. It can be as simple as a 90-degree elbow or multiple openings in the cap. A centerline of the openings is perpendicular or at an obtuse angle with respect to the direction of flow in the duct so that the intake gases do not directly access the openings and cause freezing in the openings (or ports).