[001] The present subject matter described herein, relates to a method and a system for exhaust gas heat recovery in internal combustion engine with direct and indirect fuel injection in both spark ignition (SI) and compression ignition (CI), and, in particular, a method and a system for efficient exhaust gas heat recovering in internal combustion engine for enhancing fuel consumption by faster warming up of engine afterwards engine cold start.
BACKGROUND AND PRIOR ART:
[002] In conventional internal combustion engine, during cold start operation the thermostat valve remains closed which forces the coolant to circulate within the engine. During circulation of the coolant even the heat so produced by the engine is lost to the coolant which is further lost to the engine block and engine oil. Subsequently the engine gets warmed up and this event of engine warming up is completed, as the engine achieves its desires operating temperature the thermostat valve opens and allows the coolant to flow out of the engine and cool itself thorugh the radiator and fan arrangment to maintain the said operating temperature threshold of the engine.
[003] Thus during the event of engine warm up when the said engine has not reached its desired operating temp threshold the overall friction in the engine is high leading to a demand of richer fuel consumption with respect to stoichiometry in order to prevent engine from quiting or stalling under high friction operation.
[004] US patent publication US 9631540 B2 illustrates an exhaust system and methods for efficiently recovering exhaust heat during vehicle operation. As shown in the figure 1, exhaust gas heat management system for heating engine coolant by transferring heat from an exhaust flow to the engine coolant via a heat exchanger positioned in an exhaust gas heat recovery line coupled to the EGR

cooler responsive to an EGR valve position. In particular, an exemplary EGR cooler combined with an exhaust heat recovery device is presented that allows exhaust gas to transfer heat to engine coolant via a branching pathway of the EGR cooler. That is, an exhaust system configured allows exhaust gas to be routed to both an EGR and/or the exhaust gas heat exchanger based on EGR valve actuation. In the US patent publication, the exhaust gas recirculation (EGR), the re-circulated exhaust gas passes through an exhaust gas heat exchanger where exhaust gas transfers heat to the coolant and at the end goes into the air intake manifold. Disadvantage associated with the US publication is that the coolant has to absorb the heat from the exhaust gas in the heat exchanger and returns to engine. In movement of the coolant, the coolant loses some temperature to the atmosphere. In the present US patent, heat recovery from the exhaust gas is not efficient as some extent of heat of the coolant lost to the atmosphere.
[005]
[006] Therefore, there is need in the art to develop a system and a method that directly warms up engine block during cold start operation to reduce overall engine friction by early engine block and head and sump warmup, thereby lowering heat loss and improve fuel efficiency by reducing consumption of fuel. The present subject matter provides a system and method to efficiently warm up the engine block during cold start and sub zero operation subsequent to cold start till engine has completely warmed up.
OBJECTS OF THE INVENTION:
[007] The principal objective of the present invention is to provide a method for efficient exhaust gas heat recovering in internal combustion engine for enhancing fuel consumption by warming up/ heating up engine during cold start engine operation.
[008] Another object of the present subject matter is to an exhaust gas heat recovery system for efficient exhaust gas heat recovering in internal combustion

engine for enhancing fuel consumption by warming up engine during cold start engine operation.
[009] Yet another object of the present invention is to provide a method and system for recovering exhaust gas heat for heating up the engine during cold start.
SUMMARY OF THE INVENTION:
[0010] The subject matter disclosed herein relates to an exhaust gas heat recovery system and method for efficiently recovering exhaust heat during after the event of engine cold start till complete engine warming up phase is completed during operation of vehicle. The present exhaust gas heat recovery (EGHR) system for heating up internal combustion (IC) engine during warming up phase after cold start to decrease the fuel consumption. The exhaust gas heat recovery (EGHR) system includes an engine body, an exhaust in pipe, and an exhaust out pipe. The engine body comprises a first heat transfer cavity and a second heat transfer cavity connected with each other in the engine body. The exhaust gas in pipe is provided in between the exhaust pipe and the engine body. In the system, exhaust gas in pipe transfers the exhaust gas from the exhaust pipe to the first and second heat transfer cavity of the engine body. The exhaust in pipe coupled with exhaust gas pipe at upstream to allow passage of exhaust gas from the exhaust gas pipe to the engine. The exhaust gas out pipe coupled with the exhaust gas pipe at downstream to allow passage of exhaust gas from the engine body to the exhaust gas pipe. The exhaust out pipe connects outlet of the second heat transfer cavity to the exhaust gas pipe. Further, an exhaust in valve is provided at junction of the exhaust gas in pipe and the exhaust pipe to allow passage of the exhaust gas inside the engine body to heat up the engine body and engine coolant. Furthermore, an exhaust out valve is provided at junction of the exhaust gas out pipe and the exhaust pipe to allow passage of the exhaust gas from the engine body to the exhaust pipe. Both the exhaust in valve and the exhaust out valve are actuated by the Engine Control Unit (ECU) to route back the exhaust gas into the first and the second heat transfer cavity of the engine body to heat up the engine body and the engine coolant.

[0011] In another embodiment of the present subject matter, the exhaust gas heat recovery system has two valves which are actuated by the ECU of the vehicle. Further, the ECU maintains/controls the flow of exhaust gas inside the engine body according to heat requirement of the engine. The ECU has a processor which is communicatively coupled with a memory. Further, the ECU is also coupled with a plurality of temperature sensors, such as coolant temperature sensor, engine block temperature sensor, engine head temperature sensor, engine sump temperature sensor, and engine oil temperature sensor and valve actuator. The ECU includes a temperature monitoring module to determine temperature of the engine coolant, engine block, engine head, engine sump, and engine oil based on inputs received from the plurality of temperature sensor. Further, the valve operation module of the ECU actuates the exhaust in valve and the exhaust out valve based on the inputs from the temperature monitoring module. When temperature of any of coolant, engine block, engine head, engine sump, and engine oil is less than the desired threshold, the ECU actuates the exhaust in valve and the exhaust out valve to allow passage of exhaust gas from the exhaust pipe to the exhaust in pipe to transfer the exhaust gas to the engine body through the heat transfer cavity and the second heat transfer cavity to heat up the engine coolant, the engine block, the engine head, the engine sump, and the engine oil.
[0012] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same

numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0014] Fig. 1 illustrates exhaust gas recovery system for heating up the engine coolant as known in the existing prior art.
[0015] Fig. 2 illustrates exhaust gas heat recovery system with exhaust gas in pipe and exhaust gas out pipe for efficient heat recovery, in accordance with an embodiment of the present subject matter;
[0016] Fig. 3 illustrates structure of engine with first heat transfer cavity and the second heat transfer cavity, in accordance with an embodiment of the present subject matter;
[0017] Fig. 4 illustrates Electronic Control Unit (ECU) for controlling operations of the exhaust gas heat recovery system, in accordance with an embodiment of the present subject matter;
[0018] Fig. 5 illustrates method for operating exhaust gas heat recovery system, in accordance with an embodiment of the present subject matter; and
[0019] Fig. 6 illustrates flow air intake, fuel, and exhaust gas in the engine body, in accordance with an embodiment of the present subject matter.
[0020] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0021] The subject matter disclosed herein relates to an exhaust gas heat recovery system and method for efficiently recovering exhaust heat during cold start operation of vehicle. The present exhaust gas heat recovery (EGHR) system for

heating up internal combustion (IC) engine during cold start to decrease the fuel consumption. The exhaust gas heat recovery (EGHR) system includes an engine body, an exhaust in pipe, and an exhaust out pipe. The engine body comprises a first heat transfer cavity and a second heat transfer cavity connected with each other in the engine body. The exhaust gas in pipe is provided in between the exhaust pipe and the engine body. In the system, exhaust gas in pipe transfers the exhaust gas from the exhaust pipe to the first and second heat transfer cavity of the engine body. The exhaust in pipe coupled with exhaust gas pipe at upstream to allow passage of exhaust gas from the exhaust gas pipe to the engine. The exhaust gas out pipe coupled with the exhaust gas pipe at downstream to allow passage of exhaust gas from the engine body to the exhaust gas pipe. The exhaust out pipe connects outlet of the second heat transfer cavity to the exhaust gas pipe. Further, an exhaust in valve is provided at junction of the exhaust gas in pipe and the exhaust pipe to allow passage of the exhaust gas inside the engine body to heat up the engine body and engine coolant. Furthermore, an exhaust out valve is provided at junction of the exhaust gas out pipe and the exhaust pipe to allow passage of the exhaust gas from the engine body to the exhaust pipe. Both the exhaust in valve and the exhaust out valve are actuated by the Engine Control Unit (ECU) to route back the exhaust gas into the first and the second heat transfer cavity of the engine body to heat up the engine body and the engine coolant.
[0022] In another embodiment of the present subject matter, the exhaust gas heat recovery system has two valves which are actuated by the ECU of the vehicle. Further, the ECU maintains/controls the flow of exhaust gas inside the engine body according to heat requirement of the engine. The ECU has a processor which is communicatively coupled with a memory. Further, the ECU is also coupled with a plurality of temperature sensors, such as coolant temperature sensor, engine block temperature sensor, engine head temperature sensor, engine sump temperature sensor, and engine oil temperature sensor and valve actuator. The ECU includes a temperature monitoring module to determine temperature of the engine coolant, engine block, engine head, engine sump, and engine oil based on inputs received from the plurality of temperature sensor. Further, the valve

operation module of the ECU actuates the exhaust in valve and the exhaust out valve based on the inputs from the temperature monitoring module. When temperature of any of coolant, engine block, engine head, engine sump, and engine oil is less than the desired threshold, the ECU actuates the exhaust in valve and the exhaust out valve to allow passage of exhaust gas from the exhaust pipe to the exhaust in pipe to transfer the exhaust gas to the engine body through the heat transfer cavity and the second heat transfer cavity to heat up the engine coolant, the engine block, the engine head, the engine sump, and the engine oil.
[0023] .
[0024] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0025] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise

various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0026] Figure 2 illustrates structure of engine body with exhaust gas heat recovery system, in accordance with an embodiment of the present subject matter. In figure 2, the engine body 2 connected to air intake manifold 1 at upstream and exhaust manifold 3 at downstream. The engine body 2 have a plurality of cylinders, such as one cylinder engine or combustion chamber, two cylinder engine, four cylinder engine or N number cylinder engine. Each cylinder from the plurality of cylinders has a combustion chamber which receives air and fuel from the air intake manifold and the fuel injectors, respectively and exhausts the exhaust gas via the exhaust manifold 3 which further connected with exhaust gas pipe 9.
[0027] As shown in the figure 2 and 3, the engine body 2 has first heat transfer cavity 10 and second heat transfer cavity 11. The first heat transfer cavity 10 has an inlet 10.1 and an outlet 10.2 to receive and transfer the exhaust gas. Similarly, the second heat transfer cavity 11 has inlet 11.1 which is coupled with the outlet 10.2 of the first heat transfer cavity 10 and an outlet 11.2. The outlet 11.2 of the second heat transfer cavity 11 is at the engine body 2 to transfer exhaust gas from the engine body to the exhaust gas pipe. As shown in the figure 3, the first heat transfer cavity 10 passes through cylinder head 2.1 and engine block 2.2 of the engine body 2 to transfer heat to the cylinder head 2.1 and engine block 2.2. Further, the second heat recovery line 11 passes through engine oil sump 2.3 of the engine body 2 to transfer heat to the engine oil sump 2.3. The first heat transfer cavity and the second heat transfer cavity can be provided at any location in the engine body from where efficient heat can be transferred from the exhaust gas to the engine coolant and engine body is achieved.
[0028] Referring to figure 2, the exhaust gas heat recovery system 100 has an exhaust gas in pipe 6 having an inlet 6.1 and an outlet 6.2. The outlet 6.2 of the exhaust gas in pipe 6 is coupled with the inlet 10.1 of the first heat transfer cavity 10 in the engine body 2. Further, the inlet 6.1 of the exhaust gas in pipe 6 is coupled with exhaust gas pipe 9 at upstream to allow passage of exhaust gas from

the exhaust gas pipe 9 to the engine body 2. The exhaust gas in pipe 6 has an exhaust in valve 5 at junction of the exhaust gas in pipe 6 and the exhaust pipe 9. The exhaust in valve 5 opens and closes the exhaust in pipe 6 and allows passage of exhaust gas from the exhaust gas pipe 9 to the engine body 2.
5 [0029] The exhaust gas out pipe 7 has an inlet 7.1 and an outlet 7.2. The inlet 7.1 of the exhaust gas out pipe 7 is coupled with the outlet 11.2 of the second heat transfer cavity 11 of the engine body 2. The outlet 7.2 of the exhaust gas out pipe 7 is coupled with the exhaust gas pipe 9 at downstream to allow passage of exhaust gas from the engine body 2 to the exhaust gas pipe 9 after circulation in
10 the engine body 2 via first heat transfer cavity 10 and the second heat transfer cavity 11. The exhaust gas out pipe 7 has an exhaust out valve 8 which is provided at junction of the exhaust gas out pipe 7 and the exhaust pipe 9 to allow passage of the exhaust gas from the engine body 2 to the exhaust pipe (9). The exhaust out valve 8 opens and closes to pass routed exhaust gas back into the
15 exhaust pipe 9 after recirculation in the engine body 2.
[0030] The exhaust in pipe 6 and the exhaust out pipe 7 are connected with the exhaust pipe 9 after catalyst 4 which is provided in the exhaust pipe 9 for controlling the emission. The catalyst 4 may be a selective catalytic reduction (SCR) system, three way catalyst (TWC), NOx trap, various other emission 20 control devices, or combinations thereof. In the present system, the exhaust gases heats up the catalyst 4 for proper functioning of the catalyst 4 to control the emissions, such as NOx, carbon dioxide.
[0031] As shown in the figure 2, the exhaust gas heat recovery system 100 has an Engine Control Unit (ECU) 12 which controls the actuation of the exhaust in
25 valve 5 and the exhaust out valve 8 based on the temperature condition of the engine coolant. The Engine Control Unit (ECU) 12 routed back the exhaust gas into the first heat transfer cavity 10 and the second heat transfer cavity 11 of the engine body 2 by actuating the exhaust gas valve 5 which blocks the exhaust pipe 9 and routes the exhaust gas from the exhaust gas pipe 9 to the exhaust in pipe 6.
30 The exhaust in pipe 6 transfers the routed exhaust gas to the engine body 2 via the
10

first heat transfer cavity 10 and the second heat transfer cavity 11. The routed exhaust gas transfers the heat to the engine cylinder head 2.1, the engine block 2.2 and the engine oil sump 2.3. The first heat transfer cavity 10 and the second heat transfer cavity 11 transfers the heat to the engine coolant, engine block, engine 5 head, engine sump, and engine oil. The ECU 12 also closes thermostat valve of the engine forcing the engine coolant to circulate within the engine body. The engine coolant, engine block, engine head, engine sump, and engine oil receive the required heat from the exhaust gas circulated in the first heat transfer cavity 10 and the second heat transfer cavity 11. Once the temperature of the coolant, 10 engine block, engine head, engine sump, and engine oil is above threshold temperature of the coolant, engine block, engine head, engine sump, and engine oil which is allowed for better fuel consumption, the thermostat valve is open for normal circulation.
[0032] As shown in the figure 4, the ECU 12 of the exhaust gas heat recovery
15 (EGHR) system 100 is illustrated. The ECU 600 (same as of ECU 12) is coupled with a plurality of temperature sensors 500 and exhaust gas in and out valves 700. The plurality of temperature sensors 500 includes coolant temperature sensor, engine block temperature sensor, engine head temperature sensor, engine sump temperature sensor. The ECU 500 has a processor 601, memory 602, temperature
20 monitoring module 603, and valve operating module 604. The temperature monitoring module 603 is communicatively coupled with the processor 601 and the memory 602 to receive the instructions and to calculate the instructions and to store the instructions in the memory 602. Similarly, the valve operating module 604 is communicatively coupled with the processor 601 and the memory 602 to
25 receive the instructions and to calculate the instructions and to store the instructions in the memory 602. The valve operating module 604 receives the operating instructions from the temperature monitoring module 603 to actuate the valves present in the exhaust in pipe and the exhaust out pipe; and the thermostat valve for circulation of the coolant. The ECU 600 is a microcomputer, including
30 microprocessor unit 601, input/output ports, an electronic storage medium 603 for executable programs and calibration values. The ECU 600 receives various
11

signals from sensors coupled to the engine 2, including measurement of inducted mass air flow (MAF) from mass air flow sensor, temperature information of the engine 2 from the plurality of temperature sensors 500, and valve position sensor 505. Storage medium read-only memory 603 can be programmed with computer 5 readable data representing instructions executable by processor 601 for performing the methods described below as well as other anticipated variants not specifically listed. Among other capabilities, the processor(s) 601 is configured to fetch and execute computer-readable instructions stored in the memory 602.
[0033] The functions of the various elements shown in the figure, including any
10 functional blocks labeled as “processor(s)”, may be provided through the use of
dedicated hardware as well as hardware capable of executing computer readable
instructions or logics in association with appropriate software. When provided by
a processor, the functions may be provided by a single dedicated processor, by a
single shared processor, or by a plurality of individual processors, some of which
15 may be shared. Moreover, explicit use of the term “processor” should not be
construed to refer exclusively to hardware capable of executing software, and may
implicitly include, without limitation, digital signal processor (DSP) hardware,
network processor, application specific integrated circuit (ASIC), field
programmable gate array (FPGA), read only memory (ROM) for storing software,
20 random access memory (RAM), non-volatile storage. Other hardware,
conventional and/or custom, may also be included.
[0034] The memory 602 can include any computer-readable medium known in the art including, for example, volatile memory, such as static random access memory (SRAM) and dynamic random access memory (DRAM), and/or non-25 volatile memory, such as read only memory (ROM), erasable programmable ROM, flash memories, hard disks, optical disks, and magnetic tapes. Generally construction of the ECU 600 is well known in the art. The processor 601 is operatively coupled with the memory 602 to execute the instructions for running the ECU 600. These instruction or logics may be encoded in the programs that are
12

stored in the memory 602. Further, all the output of the system and calculation of the ECU also stores in the memory 602 for future determinations.
[0035] The ECU 600 receives the temperature inputs of the engine from the plurality of temperature sensors 500 about the temperature of the engine coolant, 5 engine block, engine head, engine sump, and engine oil. The temperature monitoring module 603 monitors the inputs received from the plurality of temperature sensors 500. The temperature monitoring module 603 compares the monitored/determined temperature of the engine coolant, engine block, engine head, engine sump, and engine oil with the threshold temperature of the engine
10 coolant, engine block, engine head, engine sump, and engine oil. If the monitored temperature of any of the engine coolant, engine block, engine head, engine sump, and engine oil is below the threshold temperature, the temperature monitoring module 603 actuates the thermostat valve for the engine and the exhaust in valve 5 and the exhaust out valve 8. The actuation of the exhaust in valve 5 blocks the
15 exhaust gas pipe 9 and allow passage of exhaust gas from the exhaust pipe 9 to the exhaust in pipe 6 to transfer the exhaust gas to the engine body 2 through the heat transfer cavity 10 and the second heat transfer cavity 11 to heat up the engine coolant, the engine body 2, and engine oil sump 2.3. After recirculation of exhaust gas inside the engine body 2, the exhaust out valve 8 opens the exhaust out pipe 7
20 to allow passage of the exhaust gas from the engine body 2 to the exhaust pipe 9. In the circulation, the exhaust gas directly heats up the engine body, such as engine coolant, cylinder/engine head, engine block, engine oil and engine sump. The engine coolant receives heat from the engine body. The ECU 600 actuates the thermostat valve forcing the engine coolant to circulate inside the engine body
25 until the engine coolant attains the threshold coolant temperature. The ECU 600 monitors the temperature of the engine coolant, engine block, engine head, engine sump, and engine oil and actuates the valves accordingly, if determined temperature goes below the threshold. Further, the ECU may take combine temperature input from the engine coolant, engine block, engine head, engine
30 sump, and engine oil to activate and de-activate the system. Further, the exhaust
13

gas directly heats up the engine body which reduces the engine friction to improve the fuel consumption.
[0036] Figure 5 illustrates method for operating the exhaust gas heat recovery system, in accordance with an embodiment of the present subject matter. At step 5 402, the method 400 determines temperature of the engine coolant in the engine body. The coolant temperature sensor 500 measures the temperature of the engine coolant and provides inputs to the temperature monitoring module 603 of the ECU 600. An engine coolant temperature is determined to identify whether heat is to be transferred to the engine coolant, engine block, engine head, engine sump, and
10 engine oil during engine operation. For example in the engine cold start wherein exhaust heat is to be transferred to the engine body and the engine coolant, engine block, engine head, engine sump, and engine oil from the engine exhaust gas. The advantage of the present exhaust gas heat recovery system and operating methods is that the rate of coolant heating can be controlled based on the amount of heat
15 transferred to the engine body during operation by controlling the opening of the valve. Redirecting the exhaust gas to the engine body advantageously allows for at least a portion of heat from the engine exhaust gas to be transferred to the engine body and the engine coolant during operation.
[0037] At step 404, the method 400 determines whether the monitored
20 temperature of the engine coolant is below the threshold coolant temperature. The
temperature monitoring module 603 compares the monitored temperature with the
threshold temperature by the processor 601 and stores the output into the memory
602. Based on the comparison, if the monitored temperature of the engine coolant
is above the threshold temperature, the exhaust gas passes through the exhaust
25 pipe at step 406. If the monitored temperature of the engine coolant is below the
threshold temperature, the ECU 600 activates the exhaust gas heat recovery
system at 408. The valve operating module 604 of the ECU 600 actuates the
thermostat valve, the exhaust in valve 5, and the exhaust out valve 8 for heating
up the engine coolant, engine block, engine head, engine sump, and engine oil.
30 Based on the required heat, the ECU 600 opens the exhaust in valve 5 partially
14

and completely to control the rate of exhaust flow. Once the temperature of the engine coolant is reached to the threshold temperature, the ECU 600 deactivates the exhaust gas heat recovery system and allows passage of exhaust gas in the exhaust gas pipe 9.
5 [0038] Figure 6 illustrates flow of exhaust gas in the engine body during operation of the exhaust gas heat recovery system. The engine receives the air from air intake manifold and fuel from the fuel injectors in the combustion chamber. After the combustion, the engine releases the exhaust gases in to exhaust pipe. The exhaust pipe has a catalyst to reduce the harmful particles into the
10 exhaust gases. Further, the catalyst also receives heat from the exhaust gases for better activation and conversion of unacceptable pollutants into acceptable pollutants. After the catalyst, the exhaust gas heat recovery system has exhaust in pipe which routes the exhaust gas into the engine body to heat up the engine body and engine coolant. The routed exhaust gas goes back into the exhaust pipe via
15 exhaust out pipe.
[0039] In the present subject matter, during cold operation, the thermostat valve of the engine remains closed too forcing the engine coolant to circulate within the engine body. But during this event the post catalyst exhaust gas is circulated through the engine head block and oil sump assembly in order to improve exhaust 20 gas heat recovery during cold start operation. During the event, the addition heat is added to the engine which reduces the over all heat Loss to the coolant, engine oil and engine block during cold operation of the engine. The present system facilitates the reduction in engine friction and fuel consumption for enhancing the CO2 emissions.
25 [0040] The present system, during cold engine operation allows faster engine warm up. Subsequently as the engine gets warmed up and as the engine has achieved its desires operating temperature the thermostat valve opens and the flow exhaust flow valves (5 and 8) closes in order to prevent overheating of the engine in warmed up condition.
15

[0041] The present heat recovery system reduces engine warm up duration during cold engine start operation by directly heating the engine body instead of heating the engine coolant in a separate heat exchanger. Further, the present system, reduces CO2 emission by warming up fuel in the engine oil sump.
[0042] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.

We claim:

An exhaust gas heat recovery (EGHR) system (100) for heating up internal combustion (IC) engine after the event of cold start and during the event of engine warmup, the exhaust gas heat recovery (EGHR) system (100) comprising:
an engine body (2) comprising
a first heat transfer cavity (10) having an inlet (10.1) and an
outlet (10.2);
a second heat transfer cavity (11) having inlet (11.1) coupled
with the outlet (10.2) of the first heat transfer cavity (10) and an outlet
(11.2);
an exhaust gas in pipe (6) having an inlet (6.1) and an outlet (6.2), the outlet (6.2) of the exhaust gas in pipe (6) coupled with the inlet (10.1) of the first heat transfer cavity (10) and the inlet (6.1) of the exhaust gas in pipe (6) coupled with exhaust gas pipe (9) at upstream to allow passage of exhaust gas from the exhaust gas pipe (9) to the engine body (2);
an exhaust gas out pipe (7) having an inlet (7.1) and an outlet (7.2), the inlet (7.1) of the exhaust gas out pipe (7) coupled with the outlet (11.2) of the second heat transfer cavity (11) and the outlet (7.2) of the exhaust gas out pipe (7) coupled with the exhaust gas pipe (9) at downstream to allow passage of exhaust gas from the engine body (2) to the exhaust gas pipe (9); and
an exhaust in valve (5) provided at junction of the exhaust gas in pipe (6) and the exhaust pipe (9) to allow passage of the exhaust gas inside the engine body (2); and
an exhaust out valve (8) provided at junction of the exhaust gas out pipe (7) and the exhaust pipe (9) to allow passage of the exhaust gas from the engine body (2) to the exhaust pipe (9),
wherein the exhaust in valve (5) and the exhaust out valve (8) are actuated by the Engine Control Unit (ECU) (12) to route back the exhaust gas into the first heat transfer cavity (10) and the second heat transfer cavity

(11) of the engine body (2) to heat up the engine body (2), the engine coolant, engine block, engine head, engine sump, and engine oil.
The exhaust gas heat recovery (EGHR) system (100) as claimed in claim 1, wherein the ECU (12, 600) comprising:
a processor (601) communicatively coupled with a memory (602);
a temperature monitoring module (603) to determine temperature of the engine coolant, engine block, engine head, engine sump, and engine oil based on inputs received a plurality of temperature sensors (500);
a valve operation module (604) to actuate the exhaust in valve (5) and the exhaust out valve (8) based on the inputs from the plurality of temperature sensors (500), when temperature of the coolant, engine block ,engine head, engine sump and engine oil is less than the temperature threshold the exhaust in valve (5) and the exhaust out valve (8) are actuated to allow passage of exhaust gas from the exhaust pipe (9) to the exhaust in pipe (6) to transfer the exhaust gas to the engine body (2) through the heat transfer cavity (10) and the second heat transfer cavity (11) heat up the engine coolant, the engine (2), and engine oil sump (2.3).
The exhaust gas heat recovery (EGHR) system (100) as claimed in claim 1, wherein the first heat transfer cavity (10) passes through cylinder head (2.1) and engine block (2.2) of the engine body (2) to transfer heat to the cylinder head (2.1) and engine block (2.2).
The exhaust gas heat recovery (EGHR) system (100) as claimed in claim 1, wherein the second heat recovery line (11) passes through engine oil sump (2.3) of the engine body (2) to transfer heat to the engine oil sump (2.3).
The exhaust gas heat recovery (EGHR) system (100) as claimed in claim 1, wherein the exhaust in pipe (6) is coupled with the exhaust pipe (9) at

upstream and the exhaust out pipe (8) is coupled with the exhaust pipe (9) at downstream.
The exhaust gas heat recovery (EGHR) system (100) as claimed in claim 1, wherein the ECU (12, 600) controls rate of exhaust gas flow in the engine body (2) by controlling the opening of the exhaust in valve (5).
A method (400) for recovering exhaust gas heat for heating up internal combustion (IC) engine during cold start, the method (400) comprising:
determining (400), by Engine Control Unit (ECU) (12), temperature of engine coolant, engine block, engine head, engine sump, and engine oil based on inputs received from a plurality of temperature sensors (500);
comparing (404), by the ECU (12), the determined temperature of the engine coolant, engine block, engine head, engine sump, and engine oil with threshold temperatures;
activating (410), by the ECU (12), exhaust gas heat recovery (EGHR) system (100) when any of the determined temperature of the engine coolant, engine block, engine head, engine sump, and engine oil is less the threshold temperature.
The method (400) as claimed in claim 7, wherein the exhaust gas heat recovery (EGHR) system (100) comprises: an engine body (2) comprising
a first heat transfer cavity (10) having an inlet (10.1) and an outlet (10.2);
a second heat transfer cavity (11) having inlet (11.1) coupled with
the outlet (10.2) of the first heat transfer cavity (10) and an outlet (11.2);
an exhaust gas in pipe (6) having an inlet (6.1) and an outlet (6.2), the
outlet (6.2) of the exhaust gas in pipe (6) coupled with the inlet (10.1) of the
first heat transfer cavity (10) and the inlet (6.1) of the exhaust gas in pipe (6)

coupled with exhaust gas pipe (9) at upstream to allow passage of exhaust gas from the exhaust gas pipe (9) to the engine body (2);
an exhaust gas out pipe (7) having an inlet (7.1) and an outlet (7.2), the inlet (7.1) of the exhaust gas out pipe (7) coupled with the outlet (11.2) of the second heat transfer cavity (11) and the outlet (7.2) of the exhaust gas out pipe (7) coupled with the exhaust gas pipe (9) at downstream to allow passage of exhaust gas from the engine body (2) to the exhaust gas pipe (9); and an exhaust in valve (5) provided at junction of the exhaust gas in pipe (6)
and the exhaust pipe (9) to allow passage of the exhaust gas inside the engine
body (2) from the exhaust pipe (9); and
an exhaust out valve (8) provided at junction of the exhaust gas out pipe (7)
and the exhaust pipe (9) to allow passage of the exhaust gas from the engine body
(2) to the exhaust pipe (9); and
wherein the exhaust in valve (5) and the exhaust out valve (8) are actuated
by the Engine Control Unit (ECU) (12, 600) to route back the exhaust gas into the
first heat transfer cavity (10) and the second heat transfer cavity (11) of the engine
body (2) to heat up the engine body (2) and the engine coolant.
The method as claimed in claim 8, wherein the exhaust gas transfers the heat to the engine body (2) through the first heat transfer cavity (10) and the second heat transfer cavity (11).
The method as claimed in claim 8, wherein the ECU (12) controls opening and closing of the exhaust in valve (5) and the exhaust out valve (8) to control flow of the exhaust gas inside the first heat transfer cavity (10) and the second heat transfer cavity (11) of the engine body (2) to heat up the engine coolant.