Diesel engine and transverse turbocharger

A turbocharger is mounted on a diesel engine (e.g., a marine diesel engine), with the turbocharger's turbine axis transverse to a crankshaft axis of the engine.

BACKGROUND

1. Technical Field

Embodiments of the invention relate to engine systems. Other embodiments of the invention relate to turbocharged diesel engines.

2. Discussion of Art

Ships typically carry two types of diesel engines, namely, main propulsion engines and auxiliary engines. Both types of engine generate emissions of PM 2.5 (diesel soot), SO2 (sulfur dioxide), and NOx (nitrous oxides). Some government bodies, however, have adopted standards that will limit engine emissions, particularly NOx. For example, some of these standards apply to engines installed on U.S. vessels and to marine diesel fuels produced and distributed in the United States.

NOx emissions vary according to engine speed, combustion temperature, and the quantity of fuel burned. Lower speeds and higher combustion temperatures tend to raise the amount of NOx produced per quantity of fuel burned. As will be appreciated, low speed and high combustion temperature can be desirable characteristics of high-load internal combustion engines such as marine diesel propulsion engines. Therefore, the simplest path for reducing NOx emissions is to reduce the quantity of fuel burned per unit of useful power.

Turbochargers can be useful for enhancing fuel efficiency of piston-cylinder engines, by augmenting the mass and pressure of air inhaled into each cylinder during its intake stroke. However, turbochargers for marine diesel engines can be difficult to fit into the machinery space provided for the engines and their interfacing equipment.

As will be appreciated, it is desirable to minimize the machinery space within large ships, which are built to carry cargo. Therefore, it may be desirable to provide a marine diesel turbocharger arrangement that satisfies enhanced emissions standards, which is mounted and arranged in a more space-efficient manner than previously known, to avoid excessive use of machinery space.

BRIEF DESCRIPTION

In embodiments of a system, a turbocharger is mounted onto a diesel engine (e.g., a marine diesel engine) with a turbine axis of the turbocharger extending transverse to a crankshaft axis of the diesel engine. The turbine axis is a common axis of rotation of a turbine and a compressor of the turbocharger. (The turbocharger includes a main shaft, which is a component that connects the turbine and the compressor of the turbocharger along their common axis of rotation, i.e., along the turbine axis. Since the main shaft is coincident with the turbine axis, embodiments are equivalently described herein in regards to the main shaft of the turbocharger being oriented traverse to the crankshaft axis of the diesel engine. The main shaft of the turbocharger may define its longest dimension, and extends orthogonal to the radial width of the turbocharger.) The crankshaft axis is that axis along which the crankshaft of the diesel engine extends, typically the longest dimension of the diesel engine. “Transverse” as used herein means extending across in a generally orthogonal fashion, e.g., in an embodiment, perpendicular to one another (90 degrees plus or minus variances due to manufacturing tolerances), and in another embodiment, oriented ninety degrees plus or minus five degrees to one another. Transverse mounting of the turbocharger enables using a larger turbocharger than could be mounted axis-parallel within the same volume.

In another embodiment, a diesel engine system comprises a diesel engine (e.g., a marine diesel engine), a turbocharger mounted on the engine with a turbine axis of the turbocharger extending transverse to a crankshaft axis of the engine, and a bracket mounting the turbocharger on the engine. The system further comprises exhaust gas piping connected to supply exhaust gas from the engine to a turbine inlet of the turbocharger, charge air piping connected to supply charge air from a compressor outlet of the turbocharger with an aftercooler of the engine, and wastegate piping connected to supply exhaust gas from the engine to a turbine outlet of the turbocharger. A wastegate is installed in the wastegate piping for controlling the flow of exhaust gas to bypass the turbocharger.

DETAILED DESCRIPTION

Reference will be made below in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters used throughout the drawings refer to the same or like parts.

Referring toFIGS. 1-3, aspects of the invention relate to a system that includes a diesel engine10(e.g., a marine diesel engine) and a turbocharger12that is mounted with its turbine axis14transverse to a crankshaft axis16of the engine10. The turbocharger12includes a compressor18for pressurizing intake air, and the diesel engine includes an aftercooler20for receiving the air pressurized by the compressor18.

A compressor outlet22of the compressor18is connected with the aftercooler20by charge air piping24, which extends from the compressor outlet22in a flow direction along a first line L1that is angled (e.g., an angle greater than zero degrees, and less than 90 degrees, such as from 35 to 55 degrees) with reference to the crankshaft axis16in a plane substantially orthogonal to the turbine axis14, then along a second line L2that is angled (e.g., an angle greater than zero degrees, and less than 90 degrees, such as from 35 to 55 degrees, or, in other embodiments where this portion of the charge air piping is to be oriented more towards the vertical, from 45 to 75 degrees) with reference to the turbine axis14in a plane substantially orthogonal to the crankshaft axis16, and then along a third line L3that is substantially parallel to the crankshaft axis16and ending at the aftercooler20. (“Flow direction” refers to a direction of gas flow in an engine system when it is operating according to its intended design. For example, in an engine system comprising an engine and turbocharger, the flow direction may include and extend from a main intake, through a compressor of the turbocharger, through an intake manifold of the engine, through engine cylinders, out an engine exhaust, into a turbine of the turbocharger, and out an exhaust stack.) The charge air piping24includes a first portion26that connects to the compressor outlet22, an expansion portion28(including, e.g., an o-ring slip joint or a bellows) that continues from the first portion26, and a third portion30that connects the expansion portion28to the aftercooler20. In embodiments, an axis of the first portion26defines the first line L1referred to above, an axis of the second portion defines the second line L2referred to above, and an axis of the third portion30defines the third line L3referred to above.

The first line is shown at L1inFIG. 3. Note that in this view, the turbine axis14is orthogonal to the plane of the view. The first line L1is angled with respect to the crankshaft axis16, i.e., the angle would be defined by where the first line L1intersects the crankshaft axis16, which is omitted from this view for space purposes. The second and third lines are shown at L2and L3, respectively, inFIG. 1.

The first portion26of the charge air piping24includes an inlet flange32that is attached to the compressor outlet22, and also includes a constant flow area first bend34that extends in the flow direction from the flange32. (“Constant flow area” indicates that a cross-sectional area, interior to the piping and orthogonal to the piping centerline, is constant throughout the length of the first bend34.) Continuing in the flow direction from the first bend34, the first portion26also includes a frustoconical segment36that is attached to the first bend at an end opposite the inlet flange32. This frustoconical segment36diminishes in flow area as it extends in the flow direction from the first bend34to a flange38, which ends the first portion26. The first portion26is attached by the flange38to the expansion portion28. In an alternate design, in place of the constant area first bend34and the frustoconical segment36, a single continuously-tapering casting37may be provided, as shown inFIG. 6. The continuously-tapering casting37is of a lesser flow area adjacent the flange32and is of a greater flow area adjacent the flange38, such that the flow area of the casting increases from the compressor outlet toward the expansion joint28.

Referring back toFIGS. 1-3, the expansion portion28includes a first flange40that is secured to the first portion26, a second flange42that is secured to the third portion30, and an expansion joint44(e.g., a bellows or a sliding o-ring slip joint) that is connected between the first and second flanges40,42.

The third portion30includes a flange46that is attached to the second flange42of the expansion portion28. Continuing in a flow direction from the second flange46, the third portion30also includes a constant flow area second bend48, a flared oblong piece50, and a discharge flange52, which is connected to the aftercooler20.

The charge air piping24is mounted to the engine10by a duct bracket54. The duct bracket54includes a first ring56(seeFIG. 3) that is fastened around a middle part of the second bend48, a second ring58that is fastened around the junction of the second bend48with the flared oblong piece50, and a brace60that rigidly connects the first and second rings. The brace60is attached to the engine10.

The turbocharger12is driven by a turbine61, which receives exhaust gas from the engine10via exhaust gas piping62that is connected from an exhaust manifold of the engine to an inlet of the turbine. The turbocharger can be bypassed or de-powered by operating a wastegate valve or other control element64(generally referred to as a wastegate), which is installed in wastegate piping66that is connected from the exhaust manifold to an outlet of the turbine. The wastegate64is operable between one or more open positions that permit at least some exhaust gas to bypass the turbocharger turbine, and a closed position that prevents exhaust gas bypassing the turbocharger turbine through the wastegate piping. In one embodiment, in one of the positions of the wastegate64where exhaust gas can bypass the turbocharger turbine, all the exhaust gas bypasses the turbine, and the turbocharger is de-powered. In other embodiments, in a fully open position of the wastegate, some exhaust gas nevertheless does not bypass the turbine. In other embodiments, the wastegate is controllable from the closed position, where no exhaust gas bypasses the turbine through the wastegate piping, to a fully open position, where a maximum amount of exhaust gas bypasses the turbine through the wastegate piping, to plural intermediate positions where amounts between the two (at least some but less than the maximum) of exhaust gas bypass the turbine through the wastegate piping.

The turbocharger12is mounted to the engine10by a turbocharger bracket68, which includes a base plate70and a flange72that protrudes upward from the base plate. Referring toFIGS. 4-5, the turbocharger bracket68includes a first internal passage74for supplying oil from the engine10to the turbocharger12, and includes a second internal passage76for draining oil from the turbocharger to the engine.

In embodiments, the first internal passage74is formed partly in the flange72and partly in a rib78, which protrudes from the upward surface80of the base plate70. Within the rib78, a first segment82of the first internal passage74extends from a side84of the base plate70across the base plate, then along the base plate to the flange72. Within the flange72, the first internal passage74then extends vertically from the first segment82to a top surface86of the flange. At the flange top surface86, the first internal passage74opens from a generally circular cross section onto an oblong slot88. The oblong slot88is of moderate depth and can be removed by simply removing or machining off a certain thickness of material from the flange top surface86. Removal of the oblong slot88reveals the generally circular opening of the first internal passage74. Thus, in an unmachined condition, the turbocharger bracket68includes the oblong slot88, which connects the opening of the first internal passage74with a designed position of an oil inlet of a first variant of the turbocharger12. In a machined condition, the turbocharger bracket68does not include the oblong slot88, such that the generally circular opening of the first internal passage74is aligned with a designed position of an oil inlet of a second variant of the turbocharger12.

The second internal passage76is formed within the flange72and extends from the top surface86to a bottom surface90of the base plate70. The second internal passage76includes a dogleg segment92, which enables an upper segment94to be horizontally offset from a lower segment96.

The flange72of the turbocharger bracket68includes a body98that is contiguous with the base plate70. The body98tapers upward from the base plate to a neck100, which extends to a head102. The head102is flared outward, such that removing material from the flange top surface86will markedly reduce the width of the head102.

Although embodiments are described herein with respect to the engine having an aftercooler (which receives the charge air from the output of the turbocharger compressor), in other embodiments, the engine is not so equipped. Thus, in one embodiment more generally, where an engine may or may not have an aftercooler, a diesel engine system comprises a diesel engine (e.g., marine diesel engine) and a turbocharger that is mounted with a turbine axis of the turbocharger transverse to a crankshaft axis of the engine. The turbocharger includes a compressor and the engine includes an intake air manifold. A compressor outlet of the compressor is connected with the intake air manifold by a charge air piping extending from the compressor outlet along a first line angled with reference to the crankshaft axis in a first plane substantially orthogonal to the turbine axis, then along a second line angled with reference to the turbine axis in a second plane substantially orthogonal to the crankshaft axis, and then along a third line substantially parallel to the crankshaft axis and ending at the intake air manifold. In embodiments, the charge air piping includes a first portion that connects to the compressor outlet, an expansion portion that extends generally orthogonal from the first portion, and a third portion that extends generally orthogonal from the expansion portion to the intake air manifold.

In embodiments, the turbocharger is mounted above the engine, e.g., the turbocharger is mounted above at least the engine crankshaft and aftercooler and/or intake air manifold of the engine.

In embodiments, a diesel engine system comprises a diesel engine (e.g., marine diesel engine) and a turbocharger as set forth herein, and both charge air piping and a bracket for mounting the turbocharger to the engine as set forth herein.

In embodiments, a turbocharger is mounted on a diesel engine with a turbine axis of the turbocharger transverse to a crankshaft axis of the engine. The turbocharger includes a compressor and the diesel engine includes an aftercooler. A compressor outlet of the compressor is connected with the aftercooler by charge air piping, which extends from the compressor outlet along a first line angled with reference to the engine axis in a plane substantially orthogonal to the turbocharger axis, then along a second line angled with reference to the turbocharger axis in a plane substantially orthogonal to the engine axis, and then along a third line substantially parallel to the engine axis and ending at the intake air manifold. The charge air piping includes a first portion that connects to the compressor outlet, a expansion portion that extends generally orthogonal from the first portion, and a third portion that extends generally orthogonal from the expansion portion to the aftercooler. The first portion of the charge air piping includes an inlet flange that is attached to the compressor outlet, a constant flow area first bend that continues in a flow direction from the inlet flange, a frustoconical segment that continues in the flow direction from the first bend, and a second flange that connects the frustoconical segment to the expansion portion of the charge air piping. (In other embodiments, the first portion of the charge air pipin includes an inlet flange that is attached to the compressor outlet, a continuously expanding tapered portion that continues in a flow direction from the inlet flange, and a second flange that connects the continuously expanding tapered portion to the expansion portion of the charge air piping.) The expansion portion of the charge air piping includes a first flange that is secured to the first portion of the charge air piping, a second flange that is secured to the third portion of the charge air piping, and an expansion joint that is connected between the first and second flanges. The third portion of the charge air piping includes a second flange that is secured to the expansion portion of the charge air piping, a constant flow area second bend disposed in a flow direction from the second flange, a flared oblong piece disposed in the flow direction from the second bend, and a discharge flange attaching the flared oblong piece to the aftercooler. A duct bracket secures the charge air piping to the engine. The duct bracket includes a first ring fastened at a middle part of the second bend of the charge air piping, a second ring fastened at the junction of the second bend with the flared oblong portion of the charge air piping, and a brace connecting the first and second rings. The brace is fastened to the engine. Additionally, a turbocharger bracket mounts the turbocharger to the engine. The turbocharger bracket includes a base plate and a flange protruding upward from the base plate, with a first internal passage formed in the bracket for supplying oil from the engine to the turbocharger and with a second internal passage formed in the bracket for draining oil from the turbocharger to the engine. The first internal passage is formed partly in the flange and partly in a rib protruding from an upward surface of the base plate. A first portion of the first internal passage extends within the rib from a side of the base plate across the base plate, then along the base plate to the flange. A second portion of the first internal passage extends vertically through the flange from the first portion of the first internal passage to a top surface of the flange. The second internal passage extends vertically from a lower surface of the base plate to a top surface of the flange. The second internal passage includes a dogleg segment. In certain embodiments, the diesel engine is a marine diesel engine installed in a marine vessel.

In other embodiments, a diesel engine has a turbocharger mounted on the engine with its shaft extending transverse to a crankshaft axis of the engine. A bracket mounts the turbocharger on the engine. Exhaust gas piping is connected to supply exhaust gas from the engine to a turbine inlet of the turbocharger. Charge air piping is connected to supply charge air from a compressor outlet of the turbocharger with an aftercooler of the engine. Wastegate piping is connected to supply exhaust gas from the engine to a turbine outlet of the turbocharger, with a wastegate valve installed in the wastegate piping for permitting or preventing exhaust gas to bypass the turbocharger.

In embodiments of a system, a diesel engine (e.g., marine diesel engine) is provided with a bracket, exhaust transition piping, charge air piping, and wastegate piping for mounting a turbocharger with its turbine axis (main shaft) transverse to the crankshaft axis of the diesel engine. The bracket includes a bottom plate and an upright flange protruding generally orthogonally from the bottom plate. An upper edge of the flange includes bolt holes for mounting the turbocharger. The exhaust transition piping extends generally axially from an exhaust manifold of the engine, to a downward bend that ends at a flange for attachment to a turbine inlet of the turbocharger. The charge air piping is attached by a flange to a compressor outlet of the turbocharger, and extends generally downward from the flange, then generally axially to a side cover of the engine (e.g., an aftercooler cover). The wastegate piping extends from the exhaust transition piping to a turbine outlet of the turbocharger, and includes a wastegate (e.g., valve or other flow control device) that can be controlled to vary an amount of exhaust gas bypassing the turbocharger turbine (e.g., the wastegate can be fully opened for a maximum amount of exhaust gas to bypass the turbine, fully closed for no exhaust gas to bypass the turbine, or partially opened for an amount of exhaust gas less than the maximum to bypass the turbine).