GB2507342A

GB2507342A - A heating apparatus for an internal combustion engine which has EGR

Info

Publication number: GB2507342A
Application number: GB1219391.8A
Authority: GB
Inventors: Fiorello Losano; Salvatore Mafrici
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2012-10-29
Filing date: 2012-10-29
Publication date: 2014-04-30
Anticipated expiration: 2032-10-29
Also published as: GB2507342B; GB201219391D0

Abstract

The invention provides a heating apparatus 505 for an internal combustion engine 110 equipped with an engine oil circuit 525 which has an engine oil heat exchanger 520. The engine has an Exhaust Gas Recirculation (EGR) system (300 fig 6; 620 fig 6), a main pump 590 for circulating an engine coolant in a main coolant circuit 517, and an auxiliary pump 500 for circulating the coolant in an auxiliary coolant circuit 515. The auxiliary coolant circuit includes at least one EGR cooler 310, 510 of the EGR system, and the engine oil heat exchanger is arranged downstream of the EGR cooler. The main pump and the auxiliary pump are electrically connected to an Electronic Control Unit (ECU) 450 which can monitor an engine oil temperature in the engine oil circuit. The ECU can also energize the auxiliary pump if the monitored engine oil temperature value is lower than a predetermined threshold value.

Description

HEATING APPARATUS FOR AN INTERNAL COMBUSTION ENGINE

TECHNICAL FIELD

The present disclosure relates to a heating apparatus for an internal combustion engine.

BACKGROUND

Traditional internal combustion engines have an engine block defining at least one cylinder having a piston coupled to rotate a crankshaft. A cylinder head cooperates with the piston to define a combustion chamber.

Fuel combustion in the combustion chamber generates a significant amount of heat and a cooling circuit is generally provided in order to manage the engine temperature during the various operating phases, allowing for a correct operation of the engine and avoiding possible damages to the engine components due to excessive temperature.

An engine coolant is circulated in the cooling circuit and is sent by a coolant pump to the engine block and circulates therein exiting from a cylinder head, since the engine block and the cylinder head are equipped with a plurality of passageways cast or mach-med therein to allow the coolant fluid flow.

The coolant is then sent to a radiator which has the function of transferring heat absorbed by the coolant to the ambient air. The coolant may be a mixture of water and of an antifreeze component.

The cooling circuit is generally equipped with a main circuit line and a by-pass line, the main circuit line being equipped with the radiator and with a thermostatic valve which has the function of limiting the cooling of the engine: for example at start up, until the engine has reached a temperature sufficiently high to allow normal operation, the thermostatic valve closes temporarily the portion of the main cooling circuit that allows coolant to flow through the radiator.

The coolant may however flow through the by-pass line, even when the thermostat is closed.

Once the engine has reached a suitable operating temperature, the thermostat opens allowing cooling media to reach the radiator and cooling the media.

A switchable coolant pump or an electrical coolant pump, is often employed in the engine coolant circuit.

Accordingly1 it is possible to reduce to zero the coolant flow in the engine switching off the pump for a limited amount of time, for example in order to achieve to a faster warm up of the coolant itself especially at engine start-up in cold temperatures, thus obtaining better fuel economy.

In order to reduce NO polluting emission, most turbocharged engine system actually comprises an exhaust gas recirculation (EGR) system, which is provided for routing back and mixing an appropriate amount of exhaust gas with fresh air aspired into the Diesel engine.

Advanced EGR systems comprise a high pressure EGR conduit which fluidly connects the exhaust manifold with the intake manifold, and a low pressure EGR conduit which fluidly connects the exhaust line downstream the DPF to the intake line upstream the intake manifold.

While the high pressure EGR conduit defines a short route for the exhaust gas recirculation, the low pressure EGS conduit defines a long route which comprises also a relevant portion of the exhaust line and a relevant portion of the intake line.

In this way, the long route EGR (LRE) is effective for routing back to the intake manifold exhaust gas having lower temperature than that routed back by the short route EGR (SRE).

These advanced EGR systems are generally configured for routing back the exhaust gas partially through the SRE and partially through the LRE, in order to maintain the temperature of the induction air in the intake manifold at an optimal intermediate value in any engine operating condition.

A lubricant, such as oil, is generally provided to lubricate the engine.

An oil pump draws oil from a crankcase sump and distributes it to passages leading into the engine block. From there, the oil goes to crankshaft bearings, camshaft bearings, valve shafts and other moving metal parts that would require lubrication to help avoid excess friction and heat buildup.

Automotive vehicles are generally provided with a transmission namely a mechanical device that includes several gears in a gearbox provided for transferring torque from the crankshaft to the wheel drive, each gear defining a different gear ratio.

These gears are selectively and alternatively engaged by means of a gear lever, which may be moved directly by the driver of the motor vehicle. The gear lever may also be moved in a neutral position, where no gear is engaged and no torque is transferred to the wheel drive.

In other embodiments the transmission may be an automatic transmission or a manual-automatic transmission (MTA) in which the gears are engaged after a command of the driver by means of actuators.

In any case a lubricant, such as oil, is generally provided in a transmission oil circuit to lubricate the gearbox.

Engine oil temperature deeply influences engine friction during warm up: an higher engine oil temperature has beneficial effects in reducing engine friction.

Furthermore, transmission oil temperature influences gearbox friction: an higher transmission oil temperature has beneficial effects in reducing gearbox friction.

An object of an embodiment disclosed is improve the performance of the engine and of the gearbox, especially at start up.

A further object of an embodiment of the invention is to obtain a thermal management of the oils in the engine oil cfrcuit and in the transmission oil circuit that may improve overall fuel economy.

Still another object of the present disclosure is to meet these goals by means of a simple, rational and almost inexpensive solution.

These objects are achieved by an oil heating apparatus for an internal combustion engine, by an internal combustion engine and by a method of operation thereof according to the claims.

The dependent claims delineate preferred and/or especially advantageous aspects.

SUMMARY

An embodiment of the disclosure provides a heating apparatus for an internal combustion engine equipped with an engine oil circuit, having an engine oil heat exchanger, the engine being further equipped with an Exhaust Gas Recirculation system, the apparatus comprising a main pump for circulating an engine coolant in a main coolant circuit and an auxiliary pump for circulating the coolant in an auxiliary coolant circuit, the auxiliary coolant circuit comprising an EGR cooler of the EGR system and the engine oil heat exchanger downstream the EGR cooler, wherein the main pump and the auxiliary pump are electrically connected to an Electronic Control Unit, which is configured for monitoring an engine oil temperature in the engine oil circuit and for energizing the auxiliary pump if the monitored engine oil temperature value is lower than a predetermined threshold value thereof.

Thanks to this solution a quicker warming up of engine oil, especially at engine start up, is achieved. This may be beneficial in real life condition, particularly in connection with cold weather temperatures.

For example, in some automotive systems, an engine oil temperature of 40 °C instead of 30 °C may reduce engine friction, a phenomenon that may correspond up substantial fuel consumption savings.

Furthermore, with this embodiment, it is not necessary to equip the oil circuit with an oil cooler by-pass as in conventional applications.

According to an embodiment of the invention, the auxiliary pump is an electric pump.

An advantage of this embodiment is that the auxiliary pump may be autonomously energized by a command of the Electronic Control Unit according to the needs.

According to still another embodiment of the invention, the Electronic Control Unit is configured to activate or deactivate the main pump.

An advantage of this embodiment is that by deactivating the main pump, namely by switching off the switchable water pump during start up of the engine, a faster warm up of the coolant can be obtained and this increase of temperature can be used effectively to increase the temperature of the oils by means of the thermal interchange between the coolant and the oils in the respective heat exchangers.

According to another embodiment of the invention, the Exhaust Gas Recirculation (EGR) system comprises an high pressure EGR system and the EGR cooler is a high pressure EGR cooler.

An advantage of this embodiment is that the coolant is heated by means of the thermal exchange between exhaust gas and coolant, exhaust gas being generally at a higher temperature compared to the temperature of the coolant before reaching the oils in the respective heat exchangers.

According to a further embodiment of the invention, the Exhaust Gas Recirculation (EGR) system comprises a low pressure EGR system and the EGR cooler is a low pressure EGR cooler An advantage of this embodiment is that it can enhance the thermal exchange between exhaust gas and coolant by making use also of the temperature of the gas circulating in the low pressure EGR system before reaching the oils in the respective heat exchangers.

According to another embodiment of the invention, the auxiliary coolant circuit has a branch comprising a transmission oil heat exchanger provided in a transmission oil circuit.

An advantage of this embodiment is that it allows also quicker warming up of transmission oil, especially at engine start up.

This effect allows a further benefit in terms of reduced fuel consumption due to reduced torque loss in the transmission The combined effect of engine and transmission oil warming at start up is estimated to produce fuel economy gains in the range from 4% to 6%.

According to still another embodiment of the invention, the engine oil temperature is measured in the engine oil circuit by means of a temperature sensor connected to the Electronic Control Unit.

This embodiment has the advantage of providing a reliable measure of the temperature of the oil in the oil circuit in order to provide a signal to the Electronic Control Unit of the engine.

Another embodiment of the invention provides an internal combustion engine managed by an Electronic Control Unit and equipped with an engine oil circuit, having an engine oil heat exchanger, the engine being further equipped with an Exhaust Gas Recirculation (EGR) system and with a heating apparatus comprising a main pump for circulating an engine coolant in a main coolant circuit and an auxiliary pump for circulating the coolant in an auxiliary coolant circuit, the auxiliary coolant circuit comprising an EGR cooler of the EGR system and the engine oil heat exchanger downstream the EGR cooler, wherein the main pump and the auxiliary pump are electrically connected to an Electronic Control Unit, which is configured for monitoring an oil temperature in the engine oil circuit and for energizing the auxiliary pump if the monitored engine oil temperature value is lower than a predetermined threshold value thereof.

Another embodiment of the invention provides a method for operating an internal combustion engine equiped with an engine oil circuit, having an engine oil heat exchanger the engine being further equipped with an Exhaust Gas Recirculation (EGR) system and with a heating apparatus comprising a main pump for circulating an engine coolant in a main coolant circuit and an auxiliary pump for circulating the coolant in an auxiliary coolant circuit, the auxiliary coolant circuit comprising an EGR cooler of the EGR system and the engine oil heat exchanger downstream the EGR cooler, wherein the main pump and the auxiliary pump are electrically connected to an Electronic Control Unit, the method comprising a step of monitoring a temperature value of the engine oil and a step of energizing the auxiliary pump, if the monitored temperature value of the engine oil is lower than a predetermined threshold thereof.

According to another embodiment of the invention, the step of activating the auxiliary pump is performed when the main pump is deactivated.

According to another embodiment of the invention, the monitoring of the temperature value of the engine oil is done by measuring a signal from an oil temperature sensor, the signal being proportional to the engine oil temperature.

Advantages of these embodiments of the method of the invention are substantially the same as those described for the oil heating apparatus above.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows an automotive system; Figure 2 is a cross-section of an internal combustion engine belonging to the automotive system of figure 1; Figure 3 represents a graph of the friction between the engine's components as a function of oil temperature; Figure 4 represents a graph of coolant and oil temperatures during a new European driving cycle (NEDC): Figure 5 is a schematic representation of an oil heating apparatus according to an embodiment of the invention; Figure 6 is a schematic representation of an oil heating apparatus according to an

S

embodiment of the invention in which a detail of the EGR system is represented; and Figure 7 is a flowchart of a method of operating an internal combustion engine equipped with an oil heating apparatus according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Preferred embodiments will now be described with reference to the enclosed drawings.

Some embodiments may include an automotive system 1001 as shown in Figures 1 and 2, that includes an internal combustion engine (ICE) 110 having an engine block 120 defining at least one cylinder 125 having a piston 140 coupled to rotate a crankshaft 145.

A cylinder head 130 cooperates with the piston 140 to define a combustion chamber 150.

A fuel and air mixture (not shown) is disposed in the combustion chamber 150 and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston 140. The fuel is provided by at least one fuel injector 160 and the air through at least one intake port 210. Injectors 160 in fig. 1 are represented in a purely schematical way.

The fuel is provided at high pressure to the fuel injector 160 from a fuel rail 170 in fluid communication with a high pressure fuel pump 180 that increase the pressure of the fuel received a fuel source 190.

Each of the cylinders 125 has at least two valves 215, actuated by a camshaft 135 rotating in time with the crankshaft 145. The valves 215 selectively allow air into the combustion chamber 150 from the port 210 and alternately allow exhaust gases to exit through a port 220. In some examples, a cam phaser 155 may selectively vary the timing between the camshaft 135 and the crankshaft 145.

The air may be distributed to the air intake port(s) 210 through an intake manifold 200. An air intake line 205 may provide air from the ambient environment to the intake manifold 200. In other embodiments, a throttle body 330 may be provided to regulate the flow of air into the manifold 200. In still other embodiments, a forced air system such as a turbocharger 230, having a compressor 240 rotationally coupled to a turbine 250, may be provided. Rotation of the compressor 240 increases the pressure and temperature of the air in the line 205 and manifold 200. An intercooler 260 disposed in the line 205 may reduce the temperature of the air. The turbine 250 rotates by receiving exhaust gases from an exhaust manifold 225 that directs exhaust gases from the exhaust ports 220 and through a series of vanes prior to expansion through the turbine 250. The exhaust gases exit the turbine 250 and are directed into an exhaust system 270. This example shows a variable geometry turbine (VGT) with a VGT actuator 290 arranged to move the vanes to alter the flow of the exhaust gases through the turbine 250. In other embodiments, the turbocharger 230 may be fixed geometry and/or include a waste gate.

The exhaust system 270 may include an exhaust line 275 having one or more exhaust aftertreatment devices 280. The aftertreatment devices may be any device configured to change the composition of the exhaust gases. Some examples of aftertreatment devices 280 include, but are not limited to, catalytic converters (two and three way), oxidation catalysts, lean NO traps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, and particulate filters, such as a Diesel Particulate Filter (DPF) 278. Other embodiments may include a High Pressure exhaust gas recirculation (EGR) system 300 coupled between the exhaust manifold 225 and the intake manifold 200.

The High Pressure EGR system 300 may include a first EGR conduit 305 in which a first EGR cooler 310 is placed to reduce the temperature of the exhaust gases in the EGR system 300. An electrically controlled EGR valve 320 regulates a flow of exhaust gases in the EGR conduit of the EGR system 300. The first EGR conduit 305 defines a short route for the exhaust gas recirculation cooler, so that the exhaust gas routed back by this EGR conduit 305 is quite hot.

Furthermore, some embodiments may include a Low Pressure exhaust gas recirculation (EGR) system 620, provided with a low pressure EGR cooler 510, represented schematically in Figure 6, and that will be described in connection with that Figure.

The automotive system 100 may further include an electronic control unit (ECU) 450 in communication with one or more sensors and/or devices associated with the ICE 110.

The ECU 450 may receive input signals from various sensors configured to generate the signals in proportion to various physical parameters associated with the ICE 110.

The sensors include, but are not limited to, a mass airflow and temperature sensor 340, a manifold pressure and temperature sensor 350, a combustion pressure sensor 360, coolant temperature sensor 380, engine oil temperature sensor 385 and level sensors thereof, a fuel rail pressure sensor 400, a cam position sensor 410, a crank position sensor 420, exhaust pressure and temperature sensors 430 an EGR temperature sensor 440, and an accelerator pedal position sensor 445. Furthermore, the ECU 450 may generate output signals to various control devices that are arranged to control the operation of the ICE 110, including1 but not limited to, the fuel injectors 160, the throttle body 330, the EGR Valve 320, the VGT actuator 290, and the cam phaser 155. Note, dashed lines are used to indicate communication between the ECU 450 and the various sensors and devices, but some are omitted for clarity.

Turning now to the ECU 450, this apparatus may include a digital central processing unit (CPU) in communication with a memory system, or data carrier 460, and an interface bus. The CPU is configured to execute instructions stored as a program in the memory system, and send and receive signals to/from the interface bus. The memory system may include various storage types including optical storage, magnetic storage, solid state storage, and other non-volatile memory. The interface bus may be configured to send, receive, and modulate analog and/or digital signals to/from the various sensors and control devices.

Figure 3 represents a graph of friction mean effective pressure (FMEP) as a function of engine oil temperature.

FMEP may be calculated experimentally by known methods and is a parameter indicative of internal losses of the engine due to friction.

The temperature of the oil circulating in an engine oil circuit deeply influences FMEP and, generally speaking, warmer oil corresponds to lower engine friction and therefore to lower FMEP.

For example, as expressed in Figure 4, an oil temperature T2 higher than oil temperature Ti brings a benefits in terms of a lower FMEP value F2 with respect to a FMEP value of El corresponding to temperature Ti.

For example an oil temperature of 40°C (T2) instead of 30°C (TI) brings a benefits in FMEP at 2000 RPM (Revolutions Per Minute) of approximately 20% (F2 with respect to El), which corresponds to a benefit of approximately 4% in fuel economy. Different values may be found for different engine systems, but the principle that an higher oil temperature corresponds to lower engine friction expressed in terms of FMEP is generally valid.

Figure 4 represents a graph of engine coolant and engine oil temperatures during a new European driving cycle (NEOC). In Figure 4, curve A represents the speed of the vehicle during the NEDC, while curve B represents engine coolant temperature arid curve C engine oil temperature. The difference AT between the coolant temperature and the oil temperature may be equal to or even greater than 20°C, depending on the automotive system involved. Different values may be found for different engine cycles, the NEDC cycle being used here as an example.

Curve D represents oil transmission temperature. Transmission oil temperature is generally lower during the NEDC cycle than engine oil temperature.

Transmission oil temperature influences fuel consumption: increasing transmission oil temperature may result in lower fuel consumption.

Figure 5 is a schematic representation of an oil heating apparatus according to an embodiment of the invention.

The internal combustion engine 110 is equipped with a cooling circuit 517 for circulating a coolant through the internal combustion engine 110. The coolant circulating in the main cooling circuit 517 and in the engine 110 is sent to a radiator 560 having the function of transferring heat absorbed by the coolant to the ambient air. The coolant circulating in the engine cooling circuit 517 may be a mixture of water and of an antifreeze component.

The engine cooling circuit is equipped with a main pump 590 that sends the coolant into the engine block 120, whereby the coolant circulates therein for cooling the engine and then exits from the cylinder head 130 of the engine 110.

The main pump 590 may preferably be a switchable water pump 590 that circulates coolant between the engine.110 and the radiator 560 when the switchable water pump 590 is engaged and a thermostat 550 is open. The thermostat 550 is selectively opened to facilitate coolant flow between the engine 110 and the radiator 560. For example, the thermostat 550 may be opened when the temperature of coolant within the engine 110 exceeds a predetermined opening temperature. While the thermostat 550 is shown as being an outlet-side thermostat, in other embodiments it may be an inlet-side thermostat.

The switchable water pump 590 may be driven by the engine 110, for example by rotation of the crankshaft 145 and may be connected to an Electronic Control Unit 450 of the engine 110 that can disengage the switchable water pump from the engine 110 according to need, for example during startup of the engine 110. Engagement or disengagement of the switchable water pump 590 from the engine 110 may be achieved by known means such as an electrically actuated clutch (not represented for simplicity).

The engine 110 is further equipped with an engine oil circuit 525 for lubrication of the various mechanical components thereof, in which an oil pump 595 draws oil from a crankcase sump 610 and distributes it to passages leading into the engine block 120.

From there, the oil goes to crankshaft bearings, camshaft bearings, valve shafts and other moving metal parts that would require lubrication to help avoid excess friction and heat buildup.

An engine oil heat exchanger 520 is provided in the oil circuit 525 to cool off the oil when an excessive oil temperature threshold is reached, thus avoiding excessive temperature thereof.

Furthermore a transmission 540 is provided, namely a mechanical device that includes several gears in a gearbox provided for transferring torque from the crankshaft to the wheel drive, each gear defining a different gear ratio. These gears may be selectively and alternatively engaged by means of a gear lever, which may be moved directly by the driver of the motor vehicle. In other embodiments the transmission may be an automatic transmission or a manual-automatic transmission (MTA) in which the gears are engaged after a command of the driver by means of actuators.

A lubricant, such as oil, is generally provided to lubricate the gearbox. By means of dedicated transmission oil circuit 545 generally known in the art.

A transmission oil heat exchanger 530 may be provided in the oil circuit 545 to cool off the oil when an excessive transmission oil temperature threshold is reached, thus avoiding excessive temperature thereof. The transmission oil heat exchanger 530 is generally already present in case of automatic transmissions; in other embodiments of the invention it may be provided in the transmission oil circuit 545.

The oil heating apparatus 505 further comprises an auxiliary coolant pump 500 that circulates coolant in an auxiliary coolant circuit 515. The auxiliary coolant pump 500 draws hot coolant directly from the coolant that circulates in the engine 110. Preferably, the auxiliary pump 500 is an electric pump and can be energized following a command issued by the Electronic Control Unit 450.

The auxiliary coolant circuit 515 is designed in such a way to pass first through the high pressure EGR cooler 310 of the high pressure EGR system 300 and then through the low pressure EGR cooler 510 of the low pressure EGR system 620.

In some embodiments only the high pressure EGR system 300 may be present; in other embodiments only the low pressure EGR system 620 may be present.

Then the auxiliary coolant circuit 515 is divided in two parts, a first branch 527 that is designed to pass through the engine oil heat exchanger 520 and a second branch 537 that is designed to pass through the transmission oil heat exchanger 530.

In some embodiments the cooling circuit 515 may comprise only the engine oil heat exchanger 520.

The main cooling circuit 517 is equipped with a coolant temperature sensor 380 and the engine oil circuit 525 is equipped with an oil temperature sensor 385, both sensors 380,385 being connected to the Electronic Control Unit 450.

Figure 6 is a schematic representation of an oil heating apparatus according to an embodiment of the invention in which a detail of the EGR system is represented; and In the depicted embodiment, the engine 110 is equipped with an high pressure EGR system 300, as described above, and with a low pressure EGR system 620.

The low pressure EGR system 620 may include a low pressure EGR conduit 630, which fluidly connects a branching point 274 of the exhaust line 275 downstream the DPF 278 with a leading point 204 305 of the intake line 205 upstream the compressor 250 of turbocharger 230, and the low pressure EGR cooler 510 located in the low pressure EGR conduit 630.

The flow rate of exhaust gas through the low pressure EGR conduit 630 may be determined by an electrically controlled valve (not represented of simplicity) located in the low pressure EGR conduit 630.

The low pressure EGR conduit 630 defines a long route for the exhaust gas recirculation.

Flowing along the long route, the exhaust gas is obliged to pass through the turbine 240 of turbocharger 230, the DPF 257, the second EGR cooler 5101 the compressor 250 of turbocharger 230, so that it become considerably colder than the exhaust gas which flows through the first EGR conduit 305, thereby reaching the intake manifold at a lower temperature.

It can be seen from Figure 6 that the auxiliary circuit 515 comprises first the high pressure EGR cooler 310.

Passing through the high pressure EGR cooler 310, the coolant is heated by means of the thermal exchange between exhaust gas and coolant, exhaust gas being generally at a higher temperature compared to the temperature of the coolant.

Then the auxiliary circuit 515 comprises the low pressure EGR cooler 510.

Passing through the low pressure EGR cooler 510, the coolant is heated by means of the thermal exchange between exhaust gas and coolant by making use also of the temperature of the gas circulating in the low pressure EGR system 620.

Figure 7 is a flowchart of a method of operating an internal combustion engine equipped with an oil heating apparatus according to an embodiment of the invention.

At the start of the method, a check is made to verify if the switchable water pump 590 is on or off (block 900). If the switchable water pump 590 is on, no action is performed on the auxiliary pump 500. In any case, the auxiliary pump 500 may be deactivated once the switchable water pump 590 is on and the heat exchangers 520,530 for the oils become coolers for the oils as in conventional solutions.

On the contrary if the switchable water pump 590 is off, the auxiliary pump 500 is activated (block 910).

Energizing the auxiliary pump 500 has the effect of warming up the oil by circulating coolant in the auxiliary circuit 515.

As seen above, the coolant first circulates through the EGR system, namely through the high pressure EGR cooler 310 and the through the low pressure EGR cooler 510 (block 915).

In both these cases, the coolant is warmed by the heat exchange with the exhaust gas circulating with these EGR coolers 310,510. The extent of the warm up of the coolant is determined by many factors including the fact that in some engine operating conditions1 the exhaust gas EGR coolers 310,510 may be bypassed and therefore no thermal exchange or a minimal quantity thereof occurs.

After having passed the EGR coolers 310510, the coolant flows through the first branch 527 comprising the engine oil heat exchanger 520 and through the second branch 537 comprising the transmission oil heat exchanger 530.

Coolant circulation in the auxiliary circuit 515 may be continued maintaining the auxiliary pump 500 on until the temperature Toil, for example measured by oil temperature sensor 385, increases and reaches a threshold temperature thereof ToliTh.

This may be obtained by repeatedly checking if temperature Io is less than the threshold temperature TojiTh (block 920).

If this condition is satisfied, the auxiliary pump 500 is maintained on. When the temperature T, reaches or exceeds the threshold temperature T0, the auxiliary pump 500 is switched off (block 930).

This embodiment of the method allows the engine oil to reach quickly a suitable temperature for better operation at engine start up.

The same applies to the transmission oil temperature which is heated more effectively at start up of the engine 110.

In particular the viscosity of the transmission oil is lowered due to increased temperature thereof, reducing torque loss and thus allowing for a further decrease in fuel consumption.

For some automotive systems the increase of engine oil temperature may be around 10°C. The increase of transmission oil temperature may also be around 10°C.

The coolant how required may be provided by an auxiliary pump 500 of 40W, the provision of which has a minimal impact on engine friction.

When the engine 110 is warm, the auxiliary pump 500 may be switched off and the oil heat exchanger 520 operates as an oil cooler as per conventional solutions.

An increase in fuel economy of approximately from 4% to 6% in a New European Driving Cycle (NEDC) can be obtained. The major benefits of the embodiments of the invention disclosed are applicable in cold weather temperatures.

All the numerical values mentioned in the description for the various physical and technical parameters are merely cited as examples and may vary according to different engine systems.

Thanks to the various embodiments of the invention it is not necessary to equip the oil circuit with an oil cooler by-pass, as in conventional applications, thus saving costs.

While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.

REFERENCE NUMBERS

automotive system internal combustion engine (ICE) engine block 125 cylinder cylinder head piston crankshaft combustion chamber 155 cam phaser fuel injector fuel rail fuel pump fuel source 200 intake manifold 274 branching point of intake line 205 air intake line 210 intake airport 215 valves of the cylinder 220 exhaust gas port 225 exhaust manifold 230 turbocharger 240 compressor 250 turbine 260 intercooler 270 exhaust system 274 branching point of exhaust line 275 exhaust line 278 DPF 280 exhaust aftertreatment device 290 VGT actuator 300 HP EGR system 305 first EGR conduit 310 HP EGR coor 320 HP EGR valve 330 throttle body 340 mass airflow and temperature sensor 350 manifold pressure and temperature sensor 360 combustion pressure sensor 380 coolant temperature sensor 385 oil temperature sensor 400 fuel rail pressure sensor 410 cam position sensor 420 crank position sensor 430 exhaust pressure and temperature sensor 445 accelerator pedal position sensor 450 electronic control unit (ECU) 460 data carrier 500 auxiliary pump 505 oil heating apparatus 510 LP EGR cooler 515 auxiliary coolant circuit 517 main coolant circuit 520 engine oil heat exchanger 525 engine oil circuit 527 auxiliary coolant circuit branch to engine oil heat exchanger 530 transmission oil heat exchanger 537 auxiliary coolant circuit branch to transm. oil heat exchanger 540 transmission 545 transmission oil circuit 550 thermostat 595 oil pump 610 oil sump 620 LP EGR system 630 low pressure EGR conduit 900 block 910 block 915 block 920 block 930 block

Claims

CLAIMS1. A heating apparatus (505) for an internal combustion engine (110) equipped with an engine oil circuit (525), having an engine oil heat exchanger (520), the engine (110) being further equipped with an Exhaust Gas Recirculation (EGR) system (300,620), the apparatus (505) comprising a main pump (590) for circulating an engine coolant in a main coolant circuit (517) and an auxiliary pump (500) for circulating the coolant in an auxiliary coolant circuit (515), the auxiliary coolant circuit (515) comprising an EGR cooler (310,510) of the EGR system (300,620) and the engine oil heat exchanger (520) downstream the EGR cooler (310510), wherein the main pump (590) and the auxiliary pump (500) are electrically connected to an Electronic Control Unit (450), which is configured for monitoring an engine oil temperature (T) in the engine oil circuit (525) and for energizing the auxiliary pump (500) if the monitored engine oil temperature value (I) is lower than a predetermined threshold value thereof (TojiTh).
2. An apparatus according to claim 1, wherein the auxiliary pump (500) is an electric pump.
3. An apparatus according to claim 1, wherein the Electronic Control Unit (450) is configured to activate or deactivate the main pump (590).
4. An apparatus according to claim 1, wherein the Exhaust Gas Recirculation (EGR) system comprises an high pressure EGR system (300) and the EGR cooler is a high pressure EGR cooler (310).
5. An apparatus according to claim 1, wherein the Exhaust Gas Recirculation (EGR) system comprises a low pressure EGR system (620) and the EGR cooler is a low pressure EGR cooler (510).
6. An apparatus according to claim 1, wherein the auxiliary coolant circuit (515) has a branch (537) comprising a transmission oil heat exchanger (530) provided in a transmission oil circuit (545).
7. An apparatus according to claim 1, wherein the engine oil temperature is measured in the engine oil circuit (525) by means of a temperature sensor (385) connected to the Electronic Control Unit (450).
8. An internal combustion engine (110) managed by an Electronic Control Unit (450) and equipped with an engine oil circuit (525), having an engine oil heat exchanger (520), the engine (110) being further equipped with an Exhaust Gas Recirculation (EGR) system (300,620) and with a heating apparatus (505) comprising a main pump (590) for circulating an engine coolant in a main coolant circuit (517) and an auxiliary pump (500) for circulating the coolant in an auxiliary coolant circuit (515), the auxiliary coolant circuit (515) comprising an EGR cooler (310,510) of the EGR system (300,620) and the engine oil heat exchanger (520) downstream the EGR cooler (310510), wherein the main pump (590) and the auxiliary pump (500) are electrically connected to an Electronic Control Unit (450), which is configured for monitoring an oil temperature (T01) in the engine oil circuit (525) and for energizing the auxiliary pump (500) if the monitored engine oil temperature value (T01) is lower than a predetermined threshold value thereof (T0jITh).
9. A method for operating an internal combustion engine (110) equipped with an engine oil circuit (525), having an engine oil heat exchanger (520), the engine (110) being further equipped with an Exhaust Gas Recirculation (EGR) system (300,620) and with a heating apparatus (505) comprising a main pump (590) for circulating an engine coolant in a main coolant circuit (517) and an auxiliary pump (500) for circulating the coolant in an auxiliary coolant circuit (515), the auxiliary coolant circuit (515) comprising an EGR cooler (310,510) of the EGR system (300,620) and the engine oil heat exchanger (520) downstream the EGR cooler (310,510), wherein the main pump (590) and the auxiliary pump (500) are electrically connected to an Electronic Control Unit (450), the method comprising a step of monitoring a temperature value (T01) of the engine oil and a step of energizing the auxiliary pump (500), if the monitored temperature value of the engine oil (T01) is lower than a predetermined threshold thereof (TQIffh).
10. A method according to claim 9, wherein the step of activating the auxiliary pump (500) is performed when the main pump (590) is deactivated.
11. A method according to claim 9, wherein the monitoring of the temperature value (T011) of the engine oil is done by measuring a signal from an oil temperature sensor (385), the signal being proportional to the engine oil temperature.