Patent Description:
Internal combustion engines typically include cooling systems that circulate coolant fluid through internal parts of the engine so that waste heat is transferred from the engine to the coolant fluid. The coolant fluid is transferred from the engine to a heat exchanger to transfer heat from the coolant fluid to the external environment. Such known engines with cooling systems are disclosed in <CIT> or <CIT>.

Marine engines are types of engines that have been optimized for use with a boat or other type of watercraft device. Certain marine engines have stringent cooling requirements. For example, certain marine engine regulations specify maximum surface temperatures of the engine and exhaust systems in order to avoid injury to operators. For example, the International Convention for the Safety of Life at Sea (SOLAS) regulations stipulate that the surface temperature of components used on the high seas may not exceed <NUM> degrees Celsius. To this end, some marine engines have an exhaust cooling system in addition to an engine cooling system.

Certain marine engines are also subject to emissions standards. In general, regulated emissions for marine engines include carbon monoxide (CO), hydrocarbons, nitrogen oxides (NOx) and particulates. Such regulations have become more stringent over recent years. For example, the regulated emissions of NOx and particulates from diesel-powered marine engines are low enough that, in many cases, the emissions levels cannot be met with improved combustion technologies alone. To that end, exhaust after-treatment systems are increasingly utilized to reduce the levels of harmful exhaust emissions present in exhaust gas.

Conventional exhaust gas after-treatment systems include any of several different components to reduce the levels of regulated pollutants present in exhaust gas. For example, certain exhaust aftertreatment systems for diesel-powered engines include various components, such as a diesel oxidation catalyst (DOC), a selective catalytic reduction (SCR) catalyst, a diesel particulate filter (DPF), an SCR on filter and/or an ammonia slip catalyst (ASC) (also referred to as an ammonia oxidation catalyst (AMOX)). Each of the DOC, SCR catalyst, DPF, SCR on filter and the ASC components are configured to perform a particular exhaust emissions treatment operation on the exhaust gas passing through or over the respective components.

One embodiment relates to a system including an engine defining a water jacket. A heat exchanger is in coolant fluid receiving communication with the water jacket. The heat exchanger is structured to remove heat from the coolant fluid. An exhaust manifold is in exhaust gas receiving communication with the engine. The exhaust manifold defines an exhaust manifold cooling passage. A pump is in coolant fluid providing communication with the water jacket, and in coolant fluid receiving communication with each of the heat exchanger and the exhaust manifold cooling passage. An engine cooling circuit includes the water jacket, the heat exchanger, and the pump. An exhaust cooling circuit is in coolant fluid receiving communication with the engine cooling circuit. The exhaust cooling circuit includes the water jacket, the exhaust manifold cooling passage, and the pump. A control valve includes an inlet, a first outlet, and a second outlet. The inlet is in coolant fluid receiving communication with a first portion of the water jacket. The first outlet is in coolant fluid providing communication with a second portion of the water jacket. The second outlet is in coolant fluid providing communication with the exhaust cooling circuit. The control valve is structured to selectively control flow of coolant fluid through the second outlet.

Another embodiment relates to a method according to claim <NUM>.

These and other features, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like elements have like numerals throughout the several drawings described below.

Other features, aspects, and advantages of the disclosure will become apparent from the description, the drawings, and the claims.

It will be recognized that some or all of the figures are schematic representations for purposes of illustration. The figures are provided for the purpose of illustrating one or more implementations with the explicit understanding that they will not be used to limit the scope or the meaning of the claims.

Some marine engines utilize water-cooled engine and exhaust cooling systems in which water (e.g., raw sea water) is pumped through the engine and through the exhaust manifold to cool the engine and the exhaust manifold. In some systems, the water is subsequently injected into the exhaust gas stream to further cool the exhaust gas. Without sufficient exhaust cooling, surface temperatures of engine and exhaust components may exceed maximum rated values, which may create a fire hazard and degrade the performance of the engine.

In various conventional marine exhaust cooling systems, the coolant pump (e.g., water pump) is driven off of the crankshaft of the engine. Therefore, pump speed is correlated to engine speed. Exhaust gas cooling is most critical at high engine speeds and/or engine loads. Accordingly, exhaust gas cooling systems are designed to provide adequate cooling at worst-case operating conditions. Additionally, exhaust gas cooling is dictated at least in part by engine cooling requirements. For example, coolant (e.g., water) flow rate is the same through the engine and through the exhaust system.

One challenge with marine exhaust cooling systems is to prevent the systems from excessively cooling the exhaust gas. For example, because pump speed is correlated to engine speed, coolant is pumped through the exhaust cooling systems at all engine speeds, including low speeds. At such speeds, the surface temperature of the engine and exhaust manifold may not exceed rated limits. However, the exhaust cooling system nevertheless cools the exhaust system. As will be appreciated, this results in inefficient operation of the engine system. For example, transferring excessive exhaust energy to the engine's cooling system can result in reduced fuel efficiency.

Over-cooling the exhaust system also poses challenges regarding exhaust aftertreatment systems. Certain exhaust aftertreatment components require the exhaust gas flowing therethrough to be at or above a particular temperature for proper operation. If the exhaust gas is over-cooled prior to reaching an aftertreatment component, the exhaust gas must be heated in order for the aftertreatment component to operate properly. Exhaust gas temperature can be raised by controlling fuel injection parameters in the engine or by use of an exhaust heater or hydrocarbon doser. However, each method is inefficient because it requires introducing additional energy into the system to account for the energy that was unnecessarily removed from the exhaust gas.

Another challenge with marine exhaust cooling systems is that "wet" marine exhaust systems can preclude the use of exhaust aftertreatment components and can cause accelerated wear of exhaust components due to corrosion. For example, raw water (e.g., sea water) can impede reactions that must take place in aftertreatment components, such as oxidation catalysts or SCR catalysts. Additionally, raw water is more likely than coolant fluid to cause corrosion in exhaust components.

Various embodiments relate to an exhaust cooling system structured to actively control coolant fluid flow therethrough so as to minimize exhaust energy loss to the coolant fluid. An example embodiment includes an exhaust cooling circuit in coolant fluid receiving communication with an engine cooling circuit via a control valve. The exhaust cooling circuit comprises a turbine cooling passage defined by a turbocharger, and an exhaust manifold cooling passage defined by an exhaust manifold. The control valve is controllable between a first position, in which the coolant fluid is permitted to flow through the exhaust cooling circuit, and a second position, in which the coolant fluid is prevented from flowing through the exhaust cooling circuit.

A controller is operatively coupled to the control valve and to various other sensors. The controller is structured to minimize the flow rate of the coolant fluid through the exhaust cooling circuit while ensuring that defined limits are not exceeded. For example, in some embodiments, the controller is structured to actuate the control valve based on limits defined by one or more of (<NUM>) surface temperatures of the turbocharger and/or the exhaust manifold; (<NUM>) thermo-mechanical fatigue requirements of the turbocharger and/or the exhaust manifold; and (<NUM>) coolant fluid boiling point.

It is important to note that the exhaust cooling system, according to various embodiments, is structured to selectively use the coolant fluid that is also used by the engine cooling systems. Accordingly, the instant exhaust cooling system does not exhibit the challenges of existing systems that utilize raw water (e.g., sea water) to provide cooling to an exhaust system, such as preclusion of aftertreatment component usage and excessive corrosion. Therefore, the instant exhaust cooling system architecture enables several technical advantages by using coolant fluid rather than raw water.

In some embodiments, the exhaust cooling system further includes a drain system structured to drain coolant fluid from the exhaust cooling circuit, including from the exhaust manifold cooling passage and from the turbine cooling passage when the control valve is in the second position, in which coolant fluid is blocked from entering the exhaust cooling system. In operation, the outlet of the exhaust manifold cooling passage also operates as a drain to return the coolant from the exhaust cooling circuit to the engine cooling circuit.

Selectively draining coolant fluid from the exhaust cooling circuit solves various technical problems associated with eliminating coolant fluid flow through a cooling circuit. For example, coolant remaining in the exhaust manifold cooling passage or the turbine cooling passage may boil, which may damage the exhaust manifold and/or the turbocharger. The exhaust cooling system is also designed so as to insulate the exhaust manifold and/or the turbocharger. More specifically, removing the coolant fluid from the exhaust manifold or turbine cooling passages provides an insulating air gap between the hot exhaust gases flowing through the exhaust manifold and/or turbocharger so as to reduce their external surface temperatures.

<FIG> is a schematic block diagram of an engine system <NUM>, according to an example embodiment. The engine system <NUM> of <FIG> includes an engine <NUM>, an exhaust system <NUM>, an engine cooling system <NUM>, an exhaust cooling system <NUM>, and a controller <NUM>. In some embodiments, the engine <NUM> operates as a prime mover for an electric power generator or for a marine vehicle. The engine <NUM> may be powered by any of various types of fuels (e.g., diesel, natural gas, gasoline, etc.). As explained in further detail below, the engine <NUM> defines at least one water jacket <NUM>.

The exhaust system <NUM> includes an exhaust manifold <NUM>, a turbocharger <NUM>, and exhaust aftertreatment component <NUM>. The exhaust manifold <NUM> is operatively coupled to, and in exhaust gas receiving communication with, the engine <NUM>. The exhaust manifold <NUM> is structured to receive hot exhaust gas from exhaust ports of the engine <NUM>, and to transmit the hot exhaust gas to an exhaust pipe <NUM>, to which other components may be operatively coupled. The exhaust manifold <NUM> defines an exhaust manifold cooling passage <NUM> extending through the exhaust manifold <NUM> from an inlet <NUM> to an outlet <NUM>.

The turbocharger <NUM> includes a turbine <NUM> and a compressor <NUM>. The turbine <NUM> is in exhaust gas receiving communication with the exhaust manifold <NUM> via the exhaust pipe <NUM>. The turbine <NUM> converts some of the enthalpy contained in the exhaust gas into mechanical energy to drive the compressor <NUM>. The compressor <NUM> draws in fresh intake air, compresses it, and provides the compressed intake air to an intake manifold (not shown) of the engine <NUM>. In some instances, the compressed intake air is first provided to a charge air cooler and then to the intake manifold of the engine <NUM>. The turbine <NUM> defines a turbine cooling passage <NUM> extending through the turbine <NUM> from a second inlet <NUM> to a second outlet <NUM>.

The engine cooling system <NUM> is structured to provide cooling for the engine <NUM>. According to various embodiments, the engine cooling system <NUM> includes a pump <NUM> (e.g., a water pump), the water jacket <NUM> of the engine <NUM>, a heat exchanger <NUM>, and an engine cooling circuit <NUM>. The engine cooling circuit <NUM> defines a flow path for coolant fluid through the engine <NUM> and other components of the engine cooling system <NUM>. It should be understood that the engine cooling circuit <NUM> includes conduits (not shown) fluidly coupling the engine <NUM> and other components of the engine cooling system <NUM>. In some embodiments, the engine coolant fluid includes water. For example, the engine coolant fluid may include pure water or a mixture of water and antifreeze.

The pump <NUM> is positioned along the engine cooling circuit <NUM> upstream of the engine <NUM>. It should be understood that the terms "upstream" and "downstream," when referring to the engine cooling system <NUM>, refer to the flow direction of the coolant fluid through the engine cooling system <NUM>. The pump <NUM> is structured to circulate the coolant fluid through the engine cooling circuit <NUM>.

The water jacket <NUM> is positioned along the engine cooling circuit <NUM> downstream of, and in coolant fluid receiving communication with, the pump <NUM>. It should be noted that the water jacket <NUM> is shown in schematic form only. The water jacket <NUM> includes an intricate series of passages extending through various parts of the engine <NUM>, including a cylinder block, cylinders, and cylinder head, among other components. The water jacket <NUM> is structured to receive coolant fluid to which heat is transferred from the engine <NUM>.

The heat exchanger <NUM> is positioned along the engine cooling circuit <NUM> downstream of, and in coolant fluid receiving communication with, the water jacket <NUM>. The heat exchanger <NUM> is structured to transfer heat from the coolant fluid to another fluid medium. In some embodiments, the heat exchanger <NUM> is a keel cooler that is structured to transfer heat from the coolant fluid to raw water. In other embodiments, the heat exchanger <NUM> is an air-cooled radiator that is structured to transfer heat from the coolant fluid to air flowing therethrough. The heat exchanger <NUM> is also positioned along the engine cooling circuit <NUM> upstream of, and in coolant fluid providing communication with, the pump <NUM>. Accordingly, the coolant fluid is transmitted from the heat exchanger <NUM> to the pump <NUM>, where it is subsequently re-circulated through the engine cooling circuit <NUM>.

The exhaust cooling system <NUM> is structured to provide cooling for the exhaust system <NUM>. According to various embodiments, the exhaust cooling system <NUM> includes the water jacket <NUM>, a control valve <NUM>, the turbine cooling passage <NUM>, the exhaust manifold cooling passage <NUM>, the pump <NUM>, and an exhaust cooling circuit <NUM>. The exhaust cooling circuit <NUM> defines a flow path for coolant fluid through the engine <NUM> and other components of the exhaust cooling system <NUM>. It should be understood that the exhaust cooling circuit <NUM> includes conduits (not shown) fluidly coupling the engine <NUM> and other components of the exhaust cooling system <NUM>. In the embodiment illustrated in <FIG>, the flow path defined by the exhaust cooling circuit <NUM> is such that coolant fluid flows first through the turbine cooling passage <NUM> and then through the exhaust manifold cooling passage <NUM>. In other words, the turbine cooling passage <NUM> is upstream of the exhaust manifold cooling passage <NUM>. However, in other embodiments, the flow path defined by the exhaust cooling circuit <NUM> is such that coolant fluid flows first through the exhaust manifold cooling passage <NUM> and then through the turbine cooling passage <NUM>. In other words, the turbine cooling passage <NUM> is downstream of the exhaust manifold cooling passage <NUM>.

The control valve <NUM> is structured to selectively fluidly couple the engine cooling circuit <NUM> and the exhaust cooling circuit <NUM>. The control valve <NUM> includes an inlet <NUM>, a first outlet <NUM>, and a second outlet <NUM>. The control valve <NUM> is structured to selectively control flow of coolant fluid through the second outlet <NUM>. The inlet <NUM> is in coolant fluid receiving communication with a first portion <NUM> of the water jacket <NUM>. The first outlet <NUM> is in coolant fluid providing communication with a second portion <NUM> of the water jacket <NUM>. The second outlet <NUM> is in coolant fluid providing communication with the turbine cooling passage <NUM> and with the exhaust manifold cooling passage <NUM>. It should be noted that, in some embodiments, the exhaust system <NUM> includes one of the exhaust manifold <NUM> and the turbocharger <NUM>. Accordingly, in some embodiments, the second outlet <NUM> is in coolant fluid providing communication with one of the turbine cooling passage <NUM> and the exhaust manifold cooling passage <NUM>. In one embodiment, the control valve <NUM> is an electronic coolant thermostat.

The controller <NUM> operatively and communicatively coupled to the control valve <NUM>. The controller <NUM> is structured to controllably actuate the control valve <NUM> between a first position, a second position, and intermediate positions therebetween. When in the first position, the control valve <NUM> permits the coolant fluid to flow through the second outlet <NUM> and into the exhaust cooling system <NUM>. When in the second position, the control valve <NUM> prevents the coolant fluid from flowing through the second outlet <NUM> and into the exhaust cooling system <NUM>.

In some embodiments, the exhaust cooling system <NUM> also includes a drain system including one or more drain lines. The drain system is structured to drain coolant fluid from the exhaust cooling circuit <NUM>, including from the exhaust manifold cooling passage <NUM> and from the turbine cooling passage <NUM> when the control valve <NUM> is in the second position, in which coolant fluid is blocked from entering the exhaust cooling system <NUM>. As shown in <FIG>, the drain system includes a first drain line <NUM> including a first check valve <NUM>, and a second drain line <NUM> including a second check valve <NUM>, an expansion tank <NUM>, and a return line <NUM>. The first drain line <NUM> is in coolant fluid receiving communication with the turbine cooling passage <NUM>, and in coolant fluid providing communication with the expansion tank <NUM>. The second drain line <NUM> is in coolant fluid receiving communication with the exhaust manifold cooling passage <NUM>, and in coolant fluid providing communication with the expansion tank <NUM>. The first check valve <NUM> prevents backflow of coolant fluid to the turbine cooling passage <NUM>, and the second check valve <NUM> prevents backflow of coolant fluid to the exhaust manifold cooling passage <NUM>. In operation, the outlet <NUM> of the exhaust manifold cooling passage <NUM> also operates as a drain to return the coolant from the exhaust cooling circuit <NUM> to the engine cooling circuit <NUM>. The expansion tank <NUM> is in coolant fluid providing communication with the engine cooling circuit <NUM> via the return line <NUM>. For example, in one embodiment, the return line <NUM> fluidly couples the expansion tank <NUM> and the engine cooling circuit <NUM> upstream of the pump <NUM>.

Although not explicitly shown in <FIG>, one of ordinary skill in the art will appreciate that the engine system includes various sensors in operative communication with the controller <NUM>. For example, the engine system <NUM> includes various temperature sensors, pressure sensors, flow sensors, engine torque and load sensors, speed sensors, etc. Some temperature sensors are structured to measure a surface temperature of a component, such as the exhaust manifold <NUM>. Other temperature sensors are structured to measure a temperature of exhaust gas or coolant fluid flowing through a passage. It should be appreciated that the engine system <NUM> includes many more sensors than those mentioned herein.

<FIG> is a schematic block diagram of an engine system <NUM>, which does not form part of the invention but is described as background information. It should be understood that the engine system <NUM> of <FIG> shares various components with the engine system <NUM> of <FIG>. The engine system <NUM> of <FIG> differs from the engine system <NUM> of <FIG> in that the engine system <NUM> includes a two-way control valve <NUM> in contrast to the three-way control valve <NUM> of the system <NUM> of <FIG>. The control valve <NUM> includes an inlet <NUM> and an outlet <NUM>. The control valve <NUM> is structured to selectively control flow of coolant fluid through the outlet <NUM>. In other words, the control valve <NUM> is structured to selectively control coolant fluid flow through an exhaust cooling circuit <NUM>. The inlet <NUM> is in coolant fluid receiving communication with the pump <NUM>. The outlet <NUM> is in coolant fluid providing communication with the turbine cooling passage <NUM>.

A controller <NUM>, in a similar manner as the controller <NUM> of <FIG>, is operatively and communicatively coupled to the control valve <NUM>. The controller <NUM> is structured to controllably actuate the control valve <NUM> between a first position, a second position, and intermediate positions therebetween. When in the first position, the control valve <NUM> permits the coolant fluid to flow through the outlet <NUM> and into the turbine cooling passage <NUM>. Therefore, when in the first position, the control valve <NUM> permits the coolant fluid to flow through the exhaust cooling circuit <NUM>. When in the second position, the control valve <NUM> prevents the coolant fluid from flowing through the outlet <NUM> and into the turbine cooling passage <NUM>. Therefore, when in the second position, the control valve <NUM> blocks coolant fluid flow through the exhaust cooling circuit <NUM>.

In an alternative example, the engine system <NUM> includes two two-way control valves. A first two-way control valve is positioned upstream of the turbine cooling passage <NUM>. A second two-way control valve is positioned upstream of the exhaust manifold cooling passage <NUM>. Accordingly, in such embodiments, the turbine cooling passage <NUM> and the exhaust manifold cooling passage <NUM> are arranged in parallel rather than in series. Accordingly, in such embodiments, the first and second two-way control valves are independently controllable so as to independently control the amount of cooling provided to each of the turbine <NUM> and the exhaust manifold <NUM>.

<FIG> is a schematic block diagram of an engine system <NUM>, which does not form part of the invention but is described as background information. It should be understood that the engine system <NUM> of <FIG> shares various components with the engine systems <NUM>, <NUM> of <FIG> and <FIG>. The engine system <NUM> of <FIG> differs from the engine system <NUM> of <FIG> in that the engine system <NUM> does not include a drain system. The engine system <NUM> includes a control valve <NUM> structured to selectively fluidly couple an engine cooling circuit <NUM> and an exhaust cooling circuit <NUM>. The control valve <NUM> includes an inlet <NUM> and an outlet <NUM>. The control valve <NUM> is structured to selectively control flow of coolant fluid through the outlet <NUM>. The inlet <NUM> is in coolant fluid receiving communication with the outlet <NUM> of the exhaust manifold cooling passage <NUM>. The outlet <NUM> is in coolant fluid providing communication with the engine cooling circuit <NUM>.

A controller <NUM>, in a similar manner as the controllers <NUM>, <NUM> of <FIG> and <FIG>, is operatively and communicatively coupled to the control valve <NUM>. The controller <NUM> is structured to controllably actuate the control valve <NUM> between a first position, a second position, and intermediate positions therebetween. When in the first position, the control valve <NUM> permits the coolant fluid to flow through the outlet <NUM> and into the engine cooling circuit <NUM>. When in the second position, the control valve <NUM> prevents the coolant fluid from flowing through the outlet <NUM> and into the engine cooling circuit <NUM>.

<FIG> is a block diagram of the controller <NUM> of <FIG>. The controller <NUM> includes a processor <NUM> and memory <NUM>. It should be understood that the controllers <NUM> and <NUM> may be structured in a generally similar manner to the controller <NUM>. The memory <NUM> is shown to include an operating conditions circuit <NUM> and an exhaust cooling circuit <NUM>, each communicably coupled to the others. In general, the operating conditions circuit <NUM> and the exhaust cooling circuit <NUM> are structured to control operation of the control valve <NUM> based on monitored operating conditions of the engine system <NUM>. While various circuits with particular functionality are shown in <FIG>, it should be understood that the controller <NUM> may include any number of circuits for completing the functions described herein. For example, the activities of multiple circuits may be combined as a single circuit, additional circuits with additional functionality may be included, etc. Further, it should be understood that the controller <NUM> may further control other vehicle activity beyond the scope of the present disclosure. For example, in some embodiments, the controller <NUM> is implemented via an electronic engine control module, transmission control module, etc..

Certain operations of the controller <NUM> described herein include operations to interpret and/or to determine one or more parameters. Interpreting or determining, as utilized herein, includes receiving values by any method known in the art, including at least receiving values from a datalink or network communication, receiving an electronic signal (e.g. a voltage, frequency, current, or pulse width modulation (PWM) signal) indicative of the value, receiving a computer generated parameter indicative of the value, reading the value from a memory location on a non-transient computer readable storage medium, receiving the value as a run-time parameter by any means known in the art, receiving a value by which the interpreted parameter can be calculated, and/or by referencing a default value that is interpreted to be the parameter value.

The operating conditions circuit <NUM> is in operative communication with various sensors <NUM>. The operating conditions circuit <NUM> is structured to receive measurement values from the sensors <NUM> and to interpret measurement values based on the received measurement values. The sensors <NUM> may include any of various types of sensors configured to measure characteristics related to the engine <NUM>, the exhaust system <NUM>, the engine cooling system <NUM>, the exhaust cooling system <NUM>, and/or related systems. The sensors <NUM> may also include other temperature sensors (e.g., on the engine block, in any of the coolant passages, in the exhaust passage, or in any other location), an engine speed sensor, an engine torque sensor, a vehicle speed sensor, a position sensor, etc. Accordingly, the measurement values may include, but are not limited to, an engine temperature, a coolant temperature, an exhaust temperature, an engine speed, an engine load, a vehicle speed, a valve position, and/or any other engine or system characteristics.

The exhaust cooling circuit <NUM> is in operative communication with the operating conditions circuit <NUM>, and with the control valve <NUM> of the exhaust cooling system <NUM> of <FIG>. The exhaust cooling circuit <NUM> is structured to determine an exhaust cooling demand based on various factors (e.g., one or more of coolant temperature, component surface temperature, engine load, engine speed, vehicle speed, etc.) and to control operation of the control valve <NUM> so as to actively control coolant fluid flow through the exhaust cooling circuit <NUM>.

<FIG> is a partial cross-sectional perspective view of the engine system <NUM> of <FIG>. <FIG> illustrates various aspects of the exhaust cooling system <NUM> as implemented on the engine <NUM>. As shown in <FIG>, the exhaust system <NUM> includes the exhaust manifold <NUM> and the turbocharger <NUM>.

<FIG> illustrates portions of the exhaust cooling system <NUM>, including the turbine cooling passage <NUM>, the exhaust manifold cooling passage <NUM>, the pump <NUM>, and the exhaust cooling circuit <NUM>. The exhaust cooling system <NUM> also includes a first exhaust cooling passage <NUM> fluidly coupling the engine cooling circuit inside of the engine <NUM> and the turbine cooling passage <NUM>. The exhaust cooling system <NUM> also includes a second exhaust cooling passage <NUM> fluidly coupling the exhaust manifold cooling passage <NUM> and a coolant return <NUM>, which is fluidly coupled to a coolant inlet <NUM>. Coolant fluid flows through the exhaust manifold cooling passage <NUM> as follows. The coolant fluid flows into the first exhaust cooling passage <NUM> from the engine <NUM>. The coolant fluid flows through the turbine cooling passage <NUM> and into the exhaust manifold cooling passage <NUM>. The coolant fluid flows from the exhaust manifold cooling passage <NUM>, through the second exhaust cooling passage <NUM>, and to the coolant return <NUM>.

As illustrated in <FIG>, the exhaust cooling system <NUM> also includes an expansion tank <NUM>, a turbocharger vent line <NUM>, an exhaust manifold vent line <NUM>, and a cylinder head vent line <NUM>. The turbocharger vent line <NUM> fluidly couples the turbine cooling passage <NUM> and the expansion tank <NUM> so as to allow coolant fluid vapor to vent from the turbine cooling passage <NUM> to the expansion tank <NUM>. The exhaust manifold vent line <NUM> fluidly couples the exhaust manifold cooling passage <NUM> and the expansion tank <NUM> so as to allow coolant fluid vapor to vent from the exhaust manifold cooling passage <NUM> to the expansion tank <NUM>. The cylinder head vent line <NUM> fluidly couples a cylinder head of the engine <NUM> and the expansion tank <NUM> so as to allow coolant fluid vapor to vent from the cylinder head to the expansion tank <NUM>. The expansion tank <NUM> is fluidly coupled to the coolant return <NUM> via a coolant make-up line <NUM>. The expansion tank <NUM>, the turbocharger vent line <NUM>, the exhaust manifold vent line <NUM>, and the cylinder head vent line <NUM> account for coolant fluid expansion at higher temperatures without over-pressuring the exhaust cooling system <NUM>.

<FIG> also illustrates a first engine cooling passage <NUM> fluidly coupling the heat exchanger <NUM> (not shown in <FIG>) and the coolant inlet <NUM>.

<FIG> is a flow diagram of a method <NUM> of controlling coolant fluid flow through an exhaust cooling system so as to minimize exhaust energy losses to the coolant, according to an embodiment. The method <NUM> may be performed by the engine system <NUM> of <FIG> and <FIG>. However, it should be understood that the method may be performed in a similar manner by other systems and devices.

At <NUM>, an engine cooling system is provided. The engine cooling system includes a pump structured to circulate a coolant fluid through an engine cooling circuit including a water jacket of an engine, and a heat exchanger.

At <NUM>, an exhaust cooling system is provided. The exhaust cooling system includes a control valve, and an exhaust cooling circuit selectively fluidly coupled to the engine cooling circuit via the control valve. The exhaust cooling circuit includes an exhaust manifold cooling passage defined by an exhaust manifold. In some embodiments, the exhaust cooling circuit further includes a turbine cooling passage defined by a turbine of a turbocharger.

At <NUM>, a first temperature measurement value relating to a first surface temperature of the exhaust manifold is received from a first temperature sensor operatively coupled to the exhaust manifold. In some embodiments, a second temperature measurement second relating to a second surface temperature of the turbine housing is also received from a first temperature sensor operatively coupled to the turbine housing. Other embodiments include receiving additional temperature measurement values or other measured values.

At <NUM> The first surface temperature is determined by interpreting the first temperature measurement value. In embodiments in which additional measurement values are received, the measured parameters are determined by interpreting the received temperature measurement values.

At <NUM>, it is determined whether the first surface temperature exceeds a first predetermined value. The first predetermined value may be a maximum permitted surface temperature of the exhaust manifold. The first predetermined value may also relate to thermo-mechanical fatigue requirements of the exhaust manifold. In embodiments that include a turbocharger, it is also determined at <NUM> whether the second surface temperature exceeds a second predetermined value. The second predetermined value may be a maximum permitted surface temperature of the turbine housing. The second predetermined value may also relate to thermo-mechanical fatigue requirements of the turbine housing.

At <NUM>, a first control signal is transmitted to the control valve in response to the result of <NUM> being "YES" (the first surface temperature exceeds the first predetermined value). The first control signal causes the control valve to be actuated to a first position so as to permit coolant fluid to flow through the exhaust cooling circuit. In response to transmitting the first control signal at <NUM>, the method <NUM> returns to <NUM> to receive another temperature measurement value.

At <NUM>, a second control signal is transmitted to the control valve in response to the result of <NUM> being "NO" (the first surface temperature does not exceed the first predetermined value). The first control signal causes the control valve to be actuated to a second position so as to prevent coolant fluid flow through the exhaust cooling circuit. In response to transmitting the first control signal at <NUM>, the method <NUM> returns to <NUM> to receive another temperature measurement value.

Reference throughout this specification to "one embodiment" or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of phrases such as "in one embodiment" throughout this specification may, but do not necessarily, all refer to the same embodiment.

Additionally, the format and symbols employed are provided to explain the logical steps of the schematic diagrams and are understood not to limit the scope of the methods illustrated by the diagrams. Although various arrow types and line types may be employed in the schematic diagrams, they are understood not to limit the scope of the corresponding methods. Indeed, some arrows or other connectors may be used to indicate only the logical flow of a method. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of a depicted method. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and program code.

Many of the functional units described in this specification have been labeled as circuits, in order to more particularly emphasize their implementation independence. For example, a circuit may be implemented as a hardware circuit comprising custom very-large-scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A circuit may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

As mentioned above, circuits may also be implemented in machine-readable medium for execution by various types of processors. An identified circuit of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions, which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified circuit need not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the circuit and achieve the stated purpose for the circuit. Indeed, a circuit of computer readable program code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within circuits, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network.

The computer readable medium (also referred to herein as machine-readable media or machine-readable content) may be a tangible computer readable storage medium storing the computer readable program code. The computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. As alluded to above, examples of the computer readable storage medium may include but are not limited to a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), an optical storage device, a magnetic storage device, a holographic storage medium, a micromechanical storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, and/or store computer readable program code for use by and/or in connection with an instruction execution system, apparatus, or device.

Computer readable program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages.

Claim 1:
A system (<NUM>), comprising:
an engine (<NUM>) defining a water jacket (<NUM>);
a heat exchanger (<NUM>) in coolant fluid receiving communication with the water jacket, the heat exchanger structured to remove heat from the coolant fluid;
an exhaust manifold (<NUM>) in exhaust gas receiving communication with the engine, the exhaust manifold defining an exhaust manifold cooling passage (<NUM>);
a pump (<NUM>) in coolant fluid providing communication with the water jacket, the pump in coolant fluid receiving communication with each of the heat exchanger and the exhaust manifold cooling passage;
an engine cooling circuit comprising the water jacket, the heat exchanger, and the pump; an exhaust cooling circuit in coolant fluid receiving communication with the engine cooling circuit, the exhaust cooling circuit comprising the water jacket, the exhaust manifold cooling passage, and the pump; and
a control valve (<NUM>), comprising:
an inlet (<NUM>) in coolant fluid receiving communication with a first portion of the water jacket,
a first outlet (<NUM>) in coolant fluid providing communication with a second portion of the water jacket, and
a second outlet (<NUM>) in coolant fluid providing communication with the exhaust cooling circuit,
the control valve structured to selectively control flow of coolant fluid through the second outlet.