Description:TECHNICAL FIELD
The present disclosure relates to exhaust gas heat recovery. More particularly, the present disclosure relates to an automobile integrated exhaust heat recovery system for use during engine warm-up or cold start in automobile, and a method for operating the system with improved thermal efficiency and assembly flexibility.
BACKGROUND
The exhaust heat recovery system (EHRS) is applied in automobile to capture and repurpose the waste heat recovery from vehicle’s exhaust gases. This heat energy, which is typically lost to the environment, can be converted into useful energy to improve fuel efficiency, reduce emissions of harmful pollutants. It can be also used for cabin heating - the heat can be used to warm the cabin more quickly- especially during cold weather. EHRS has potential to increase fuel efficiency generally by 8-10%. EHRS system also reduces emissions significantly. The traditional EHRS system has two gas flow paths; one, main gas flow path; and second, by-pass valve to direct gases to heat exchanger to recover heat. The main gas flow path has a control valve to regulate gas flow in main passage and heat exchanger. The atmospheric temperature in winter is low in cold countries. Therefore, more time is required for engine to reach warm up condition. Part of lost exhaust gas heat is recovered in EHRS; and utilised to heat coolant to reduce overall warmup time.
In conventional system, the coolant flow is in counter direction with the hot exhaust gases. The EHRS valve actuator is slider crank mechanism type with reciprocating arm has point contact with rotating lever arm. The lever arm remains contact with reciprocating actuator with coil spring. The valve has circular functional area to control the circular tube gas passage. The EHRS device that recovers the heat of the exhaust gas of the internal combustion engine is assembled in the exhaust pipe to recover the engine waste heat. It is becoming common to pass engine coolant from EHRS to recover engine exhaust gas heat. The exhaust heat recovered by the coolant helps to raise engine coolant temperature faster thereby it reduces the coolant warm-up time during engine start.
The structural distance between the coolant circuit and the heat exchanger may lead to additional heat losses along the coolant’s transit path, diminishing the effective transfer of thermal energy from the heat core.
In patent reference WO2020/117892, the exhaust recovery system includes housing assembly, a heat exchanger, and valve assembly that are coupled to recover heat from exhaust gas. Since the heat exchanger core is embedded inside the EHRS, the cold regions environmental heat convections losses are higher thus reducing efficiency. The electronically controlled valve assembly functions along the required path to reduce distortions caused by vehicle vibrations. However, the reliance on a coil spring to maintain consistent contact between the lever arm and the reciprocating actuator may lead to performance variability over time, particularly if the spring's force degrades and compromises system efficiency.
Therefore, there is a need for technology that provides enhanced thermal efficiency by minimizing heat loss, and achieve improved assembly flexibility.
SUMMARY
In one aspect of the present disclosure, an integrated exhaust heat recovery system is provided.
The integrate exhaust heat recovery system includes a heat exchanger and a valve assembly. The heat exchanger is operatively coupled between two tapered coolant tanks. The coolant contained within the tapered coolant tanks is transferred to plate tubes for extracting heat from exhaust gases that flow through air fins affixed to the plate tubes. The valve assembly is configured to control the position of a valve to guide the exhaust gases along one of two distinct flow paths, wherein the selection of the flow path is based on engine operating conditions and a desired heat recovery output.
In some aspects of the present disclosure, the exhaust heat recovery system further includes a top manifold, middle manifold and main manifold that are adapted to integrate the heat exchanger and valve assembly.
In some aspects of the present disclosure, the heat exchanger comprises corrugated air fins attached to plate tubes, wherein the air fins are configured to direct exhaust gas through the plate tubes. The inlet coolant tank is configured to retain coolant proximate to the inlet end of the plate tubes, while the outlet coolant tank is configured to retain heat-recovered coolant proximate to the outlet end of the plate tubes. Both tanks are positioned in close proximity to the heat exchanger to facilitate rapid coolant transfer with minimal heat loss. Furthermore, the design of the coolant tanks ensures improved pressure distribution.
In some aspects of the present disclosure, the heat exchanger facilitates better heat transfer between the gas and the coolant by employing the corrugated air fins affixed to the plate tubes.
In some aspects of the present disclosure, the valve assembly comprises a first valve plate that is adapted to provide an increased main path flow area for exhaust gas to pass through the exhaust gas outlet in open condition. The first valve plate is actuated in response to a signal received from a second valve plate. The third valve plate is adapted to be urged against an opening in a middle manifold, thereby sealing the path without leaks or gaps.
In some aspects of the present disclosure, the valve assembly comprises the first valve plate that is positioned against the valve baffle in closed condition, wherein the first valve plate is adapted to block the main exhaust gas flow and divert the exhaust gas to heat exchanger for full active heat recovery.
In some aspects of the present disclosure, a method for operating exhaust heat recovery system comprises directing the exhaust gas via two distinct exhaust gas flow paths. In a normal operating mode, the exhaust gas is directed through the main exhaust gas flow path in an open state of the valve. In a heat recovery mode, the exhaust gas is directed through the bypass exhaust gas flow path to the heat exchanger in closed state of the valve. The heat from the exhaust gas is captured by the air fins. The coolant and the exhaust gas are distributed through the heat exchanger in counter-cross flow direction. The exhaust heat is transferred from coolant in plate tubes. The heat recovered coolant is sent to coolant outlet.
BRIEF DESCRIPTION OF DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this specification, show certain aspects of the subject matter disclosed herein and, together with the description, help explain some of the principles associated with the disclosed implementations. In the drawing,
Figure 1A illustrates a schematic diagram of the automotive exhaust heat recovery system, in accordance with an aspect of the present disclosure;
Figure 1B shows an exploded view of the integrated exhaust heat recovery system, in accordance with an aspect of the present disclosure;
Figure 2 illustrates a heat exchanger of the automotive exhaust heat recovery system of figure 1, in accordance with an aspect of the present disclosure;
Figure 3 illustrates the schematic diagram of the valve assembly in the exhaust heat recovery system of figure 1, in accordance with an aspect of the present disclosure;
Figure 4 shows a schematic diagram depicting the flow of the exhaust gas through the valve in open condition, in accordance with an aspect of the present disclosure.
Figure 5 shows a schematic diagram illustrating the exhaust gas flow through the valve in closed condition.
Figure 6 shows an isometric view of the integrated exhaust heat recovery system.
Figure 7 shows a schematic diagram illustrating the valve actuation mechanism with thermostat.
Figure 8 shows a flowchart illustrating the method for operating the exhaust heat recovery system 100.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various embodiments of the disclosure are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the disclosure. Thus, the following description and drawings are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the disclosure. However, in certain instances, known details are not described in order to avoid obscuring the description.
References to one or an embodiment in the present disclosure can be references to the same embodiment or any embodiment; and, such references mean at least one of the embodiments.
Reference to "one embodiment", "an embodiment", “one aspect”, “some aspects”, “an aspect” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others.
The terms used in this specification generally have their ordinary meanings in the art, within the context of the disclosure, and in the specific context where each term is used. Alternative language and synonyms may be used for any one or more of the terms discussed herein, and no special significance should be placed upon whether or not a term is elaborated or discussed herein. In some cases, synonyms for certain terms are provided.
A recital of one or more synonyms does not exclude the use of other synonyms.
The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only, and is not intended to further limit the scope and meaning of the disclosure or of any example term. Likewise, the disclosure is not limited to various embodiments given in this specification. Without intent to limit the scope of the disclosure, examples of instruments, apparatus, methods and their related results according to the embodiments of the present disclosure are given below. Note that titles or subtitles may be used in the examples for convenience of a reader, which in no way should limit the scope of the disclosure. Unless otherwise defined, technical and scientific terms used herein have the meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In the case of conflict, the present document, including definitions will control.
Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or can be learned by practice of the herein disclosed principles. The features and advantages of the disclosure can be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the disclosure will become more fully apparent from the following description and appended claims, or can be learned by the practice of the principles set forth herein.
As mentioned before, there is a need for technology that overcomes these drawbacks, is more thermally efficient, has better pressure distribution and provides improved assembly flexibility. The present disclosure also provides an automotive exhaust heat recovery system that addresses these issues by capturing waste heat from exhaust gas system and converts it into usable energy through a unique heat exchanger coupled with a fluid transfer system. The coolant fluid is circulated around the heat transfer channels to absorb heat from the exhaust gas circulation. A control unit is adapted to regulate the flow rate of the exhaust gases based on engine operating conditions and desired heat recovery output.
Figure 1A illustrates a schematic diagram of the automotive exhaust heat recovery system, in accordance with an aspect of the present disclosure.
The automotive exhaust heat recovery system 100 may include a heat exchanger 200, a valve assembly 300, a thermostat 400 and an exhaust pipes 500, 900.
The system comprises a heat exchanger 200 that is integrated with the exhaust pipe 500 and a valve assembly 300 with valve actuation mechanism. The coolant fluid from the tapered coolant tanks 202a, 202b flows in straight whereas the exhaust gas flows in counter-cross direction. The heat exchanger 200 has a dual flow coolant and exhaust gas design to enhance heat transfer efficiency. The thermostat 400 is adapted to control the valve actuation mechanism. The tapered coolant tanks 202a, 202b are trapezoidal in shape which are connected by plate tubes at the ends of the heat exchanger. The plate tubes are embedded with air fins 204 for better convective heat transfer from hot exhaust gases to coolant liquid. The exhaust gas inlet 500 is where the exhaust heat gas enters the automotive exhaust heat recovery system 100 and flows in different paths according to the operating conditions. In normal mode, the exhaust gas flows through main exhaust gas flow path 402 when the valve is in open condition. In heat recovery mode, the exhaust gas flows through the heat exchanger 200 for effective heat transfer in bypass exhaust gas flow path 5027 when the valve is in closed condition, where the paths are activated by the valve mechanism as per engine operational requirements. The heat exchanger 200 of the automotive exhaust heat recovery system 100 has exhaust gas flowing over the coolant fluid core. The heat exchanger core is embedded in exhaust system 100, so it is isolated from the external environment. The valve assembly 300 connected to the thermostat 400 is a two-way control mechanism for regulating the flow of the exhaust gas. Aspects of the present disclosure comprises coolant tank that are also in trapezoidal shape by way of example and not limitation to any shapes with wider opening and narrow ending may also be included in the disclosure.
Figure 1B shows an exploded view of the integrated exhaust heat recovery system 100, in accordance with an aspect of the present disclosure.
The exhaust heat recovery system 100 may further comprises cone covers 600a, 600b, a top manifold 102, a middle manifold 104, a main manifold 106, a coolant inlet pipe 800, a coolant outlet pipe 700, a thermostat housing 400, a thermostat outlet (not shown), a thermostat bracket 108 and a valve baffle 110. The exhaust gas inlet 500 and exhaust gas outlet 900 are integrated to the automotive exhaust heat recovery system 100 via the cone covers 600a, 600b positioned at the entry and exit of the system 100, respectively. The coolant inlet pipe 800 connected to heat exchanger 200 may be adapted to transfer the coolant to the inlet coolant tank 202a. The coolant outlet pipe 700 may be adapted to transfer heat recovered coolant from the outlet coolant tank 202b for cabin heating and engine warmup. The top manifold 102 may be positioned at the top of the plate tubes 206 to cover the system 100, the middle manifold 104 may be adapted to connect the heat exchanger 200 and the valve assembly 300. The middle manifold 104 may be designed to have two paths for enabling the flow of gas through exhaust pipe to heat exchanger 200. The main manifold 104 may be placed in the way of exhaust pipe at the bottom of the system 100 to pass the exhaust gas flowing. The thermostat 400 may be adapted to control the valve assembly. The valve baffle 110 may be positioned proximate to a valve plate 308a on the middle manifold 104, serving as a stopper to limit valve movement to a predefined position. The system 100 may effectively capture and utilize heat from exhaust gases, achieving approximately ~60% efficiency in coolant heat gain, and with a pressure drop of approximately 12.5 mbar, which is lower than that observed in prior exhaust heat recovery systems.
Figure 2 illustrates a heat exchanger 200 of the automotive exhaust heat recovery system 100 of figure 1, in accordance with an aspect of the present disclosure.
The heat exchanger 200 comprises tapered end tanks 202a, 202b, heat transfer coolant plate channels 206, air fins 204, and baffles 208. The heat exchanger features a dual-flow design to enhance heat transfer efficiency. The hot exhaust gases flow over the coolant plates tubes 206. The tapered coolant tanks 202a, 202b are adapted at the inlet of the coolant channels for better equal pressure distribution. An inlet coolant tank 202a is adapted to store the coolant near the heat exchanging plates, and an outlet coolant tank 202b that is adapted to store heat recovered coolant. Heat transfer coolant plate channels 206 are provided to transfer heat from the exhaust gas to the coolant present in the coolant plate channel. The corrugated air sheet fins 204 are positioned in between the transfer plates 206 for effective convective heat transfer to coolant core. C-type baffle 208 and cross wave fins are designed for better distribution of the exhaust gas with cross flow path in combination with counter flow path with coolant flow to increase flow path over coolant surfaces. This increases convective energy transfers if compared to counter flow alone and makes it compact. The baffles 208 are also provided around the heat exchanger 200 to hold the increase structural stiffness providing structural integrity.
In some aspects of the present disclosure, the heat exchanger may further comprise fin boxes 210a, 210b, and fin tubes 206. The fin tubes 206 are configured to transfer coolant within the heat exchanger 200 and to retain the air fins 204. The fin boxes 210a, 210b are arranged to secure the transfer plates in place. The heat exchanger 200 is designed for use in a small-scale automotive exhaust gas heat recovery system 100 and exhibits an effectiveness of approximately 60%.
In some aspects of the present disclosure, the heat exchanger may further comprise at least two coolant tanks 202a, 202b, at least two fin boxes 210a, 210b, at least four fin tubes 206, at least three set of fins, at least one valve baffle 110 and at least three C-type baffles 208. But the person skilled in the art can vary the number of these elements based on the requirement.
In some aspects of the present disclosure, the tapered coolant tanks 208a, 208b may be adapted to enhance the uniform distribution of coolant throughout the system, thereby improving overall pressure distribution. In another aspects of present disclosure, the tapered tanks may be adapted to provide stabilized low-pressure distribution.
In some aspects of the present disclosure, the coolant from the inlet coolant tank 202a may be directed through the fin tubes 206, thereby establishing a counter flow. Concurrently, exhaust gas may be conveyed through the air fins 204 in the bypass exhaust gas path, thereby creating a cross flow. In some aspects of the present disclosure, the exhaust gases flow through the channels or tubes in one direction while the coolant flows in the opposite direction. As a result, the hotter exhaust gases transfer heat to the cooler coolant more effectively. The counter-cross flow configuration is designed to maximize the temperature differential between the fluids, thereby enhancing heat transfer efficiency.
In some aspects of the present disclosure, the thermostat 400 may be connected to the coolant inlet pipe 800 that monitors the inlet coolant temperature. The thermostat 400 may be adapted to actuate the valve mechanism according to the engine operating requirements and desired heat recovery output.
Figure 3 illustrates the schematic diagram of the valve assembly 300 in the exhaust heat recovery system 100 of figure 1, in accordance with an aspect of the present disclosure.
The valve assembly 300 may comprise a valve rod 302, a collar bush 304, a roller cover 306, a first valve plate 308a, a second valve plate 308b, a third valve plate 308c, and a bush 314. The valve rod 302 may be attached to the roller cover 306 by securing the collar bush 304 at its upper end and the bush 314 at its bottom end. The first, second, and third valve plates 308a-308c attached together to form valve 308, where the first valve plate 308a may act as the door to get in contact with the valve baffle. The second valve plate 308b may be connected at the back of the first valve plate 308a, and the third valve plate 308c may be connected at the back of the second valve plate 308b. Aspect of the present disclosure comprises the valve including but not limited to check valve, non-return valve, reflux valve, retention valve, foot valve or one-way valve etc.
In some aspects of the present disclosure, the valve rod 302 may be actuated by a thermostat signal, thereby transmitting motion to the roller cover 306 to actuate a valve 308. The valve 308 may be activated by an integrated slider crank (Scotch yoke) mechanism, which includes a valve actuation arm (second valve plate 308b) and requires an actuation force of approximately 10 N. In these embodiments, the valve rod 302, the roller cover 306, and the second valve plate 308b function collectively as a slider crank mechanism. Since the second valve plate 308b is connected within the cam slot (roller cover), the external vibrations or misalignment due to vibration are countered within the cam slot. The second valve plate (308b), valve rod 302 and the roller cover 306 operate collectively as a contact slide closed-circuit cam mechanism and does not require any spring force for valve actuation. The connecting arm is slotted type and it is integrated with a reciprocating piston arm. The pin (not shown) on the connecting arm of a rotating lever is slidably engaged in the slot during the reciprocation of the piston arm, ensuring that the pin remains continuously in contact with the slot without the need for any external component, thereby ensuring the integrity of the mechanism.
In some aspects of the present disclosure, valve 308 may be adapted to open at 60 degrees and only requires a minimal opening force of 10N. The valve 308 used is two-way control mechanism. The first valve plate 308a may be of D-shape with an opening area of 965mm2, this ensures that the main exhaust gas flow path is maximized, which helps to seal off the bypass path with the assistance of the third valve plate 312, thereby preventing exhaust gases from existing the heat exchanger 200 in an unintended manner. The valve 308 may be configured to require an actuation force of approximately 10N. This relatively low force requirement is achieved through the optimized design of the cam-based actuation mechanism, which includes a slider-crank system that converts rotational motion into precise linear movement. The 10N force is sufficient to reliably move the valve into its operative position, ensuring that exhaust gases are effectively directed through the main flow path and bypass exhaust gas flow path based on the regulation. Aspects of the present disclosure may also include any shapes that match the valve baffle to provide an increased effective main flow path area, and the opening force may include changed newton values according to requirement of the person skilled in the art.
Figure 4 shows a schematic diagram depicting the flow of the exhaust gas through the valve in open condition.
In open condition, the valve 308 that is connected to the thermostat 400 may pass exhaust gas through the main exhaust gas flow path 402 and may be adapted to cause the third valve plate 308c to contact the middle manifold 104. The D-shaped valve plate 308a is configured to provide an increased effective flow area. The effective opening area of approximately 965 mm² is engineered to maximize the main exhaust gas flow path. The flat edge of the D-shaped valve plate facilitates uniform and tight contact with an adjacent sealing surface or valve element, such as a third valve plate, thereby minimizing gaps and leak paths. This configuration not only increases the flow area for exhaust gases but also effectively seals off the bypass route, ensuring that exhaust gases are directed exclusively through the main flow path to prevent the risk of damage due to overheating.
Figure 5 shows a schematic diagram illustrating the exhaust gas flow through the valve in closed condition.
In closed condition, the valve 308 may be engaged against the valve baffle, effectively sealing off the main flow path. Consequently, the exhaust gas is directed exclusively at the heat exchanger 200 in the by-pass exhaust gas flow path 502, ensuring that the thermal energy is recovered. As the exhaust gas enters the heat exchanger, it flows through the air fins 204 arranged in a crossflow configuration relative to the coolant circulating within the fin tubes 206. This counter-cross flow arrangement may facilitate efficient heat transfer from the exhaust gas to the coolant, optimizing the overall performance of the heat recovery system.
In some aspects of the present disclosure, within the heat exchanger 200, the incoming exhaust gases encounter an array of air fins 204 arranged in a crossflow configuration relative to the coolant flowing through the plate tubes 206. The air fins 204 and plate tubes 206 are integrally designed to promote efficient heat exchange. The counter-cross flow arrangement maximizes the contact surface between the hot exhaust gases and the cooled surfaces of the plate tubes, thereby enhancing heat transfer efficiency.
Figure 6 shows an isometric view of the integrated exhaust heat recovery system 100.
The exhaust gas flows through the inlet pipe 500 to the exhaust heat recovery system 100. The coolant fluid may enter the coolant inlet after passing through the thermostat 400 to the inlet coolant tank 202a. The coolant is subsequently transferred from the inlet coolant tank 202a to a coolant outlet via plate tubes affixed to the coolant tanks. The plate tubes are configured to extract thermal energy from the exhaust gas as the gas traverses adjacent air fins 204. The valve assembly may be provided to regulate the exhaust gas flow rate in accordance with the operating conditions. The valve 308 is selectively actuated between open and closed states to regulate the exhaust gas flow for efficient thermal energy recovery. In the open state, valve 308 may be configured to provide an unobstructed flow path for the exhaust gases and may be adapted to engage the middle manifold opening, thereby sealing the bypass exhaust gas flow path 502 and preventing the exhaust gases from diverting from the main exhaust gas flow path 402. This arrangement ensures that the exhaust gases remain in the main flow line in open state. Moreover, valve 308 is adapted to achieve complete closure of the opening, as the D-shaped first valve plate 308a is designed to provide an increased flow area when in the open state, allowing the exhaust gas to exert sufficient force to return the valve to the closed position with minimal actuation force. In closed state, the valve 308 may be provided to block the main exhaust gas flow path and may be adapted to contact the valve baffle 110 leading the exhaust gas to flow through the bypass exhaust gas flow path 502 for heat recovery. The coolant with recovered heat is used for cabin heating or other purposes during other operating conditions of engine. The integration of heat exchanger 200 with coolant tanks 202a, 202b and cam-based valve actuation mechanism offers a compact and versatile solution. The coolant flows through the air fins 204 of the heat exchanger 200.
Figure 7 shows a schematic diagram illustrating the valve actuation mechanism with thermostat.
The valve actuation mechanism may comprise the thermostat 400 and the valve assembly 300 the operate in open and closed conditions. The signal from thermostat 400 may actuate the valve assembly 300 by activating the valve rod 302 which in turn move the valve 308 to open or close for efficiently controlled exhaust gas flow. The first valve plate 308a may be dimensioned to correspond with the size and shape of the valve baffle, thereby enabling an increased effective flow area. In some aspects of the present disclosure, the first valve plate 308a is precisely dimensioned and configured to match the size and shape of the valve baffle. This careful matching ensures that, when the valve plate engages with the baffle, it creates a uniform and maximized opening for exhaust gas flow. By aligning the geometries of these two components, any potential gaps or obstructions are minimized, which in turn increases the effective flow area. This enlarged flow area enhances the throughput of exhaust gases, improving the overall efficiency of the heat recovery process by facilitating better heat transfer within the system.
Figures 8 shows a flow diagram illustrating the method for operating the exhaust heat recovery system 100.
The method 800 for operating the exhaust heat recovery system comprising:
Step 802: actuating the valve to direct the exhaust gas flow through two paths;
Step 804: directing the exhaust gas in the effective main flow path by valve at opening force;
Step 806: directing the exhaust gas valve in the bypass flow path to the heat exchanger by the valve;
Step 808: capturing the heat from hot exhaust gas by air fins;
Step 810: transferring heat from coolant in the plate tubes; and
Step 812: sending heat recovered coolant to the coolant outlet.
In an exemplary scenario, the system demonstrates how the automotive exhaust heat recovery system effectively captures waste heat from the exhaust gas, converts it into usable energy, and adapts dynamically to changing engine conditions. This integrated approach overcomes traditional drawbacks by offering improved thermal efficiency, better pressure distribution, and enhanced assembly flexibility—all of which contribute to improved vehicle performance and energy efficiency.
In another exemplary scenario, the system operates in an automotive vehicle that is cruising on a highway where the engine is operating at a steady state. In this scenario, the exhaust gas heat recovery system is actively engaged to capture waste thermal energy from the engine’s exhaust. As hot exhaust gases exit the engine through the exhaust pipe, they enter the system via the exhaust gas inlet. The integrated heat exchanger, which is embedded within the exhaust system, begins its work immediately, using a dual-flow design to facilitate efficient heat transfer between the exhaust gases and the circulating coolant. Inside the heat exchanger, the coolant fluid flows through channels arranged in straight flow whereas exhaust gas flow in a counter cross flow direction relative to the exhaust gases. As the exhaust gas passes over the plate tubes and across the air fins, the hot gases transfer a substantial amount of heat to the cooler fluid. This design not only enhances the heat transfer efficiency but also minimizes thermal losses by isolating the heat exchanger core from the external environment. The tapered coolant tanks at each end of the exchanger help distribute the coolant evenly, ensuring that the pressure remains balanced throughout the system. The system’s operation is further optimized by an electronically controlled valve assembly connected to a thermostat. Under normal conditions, the valve remains open, allowing exhaust gases to flow through the main exhaust path uninterrupted. However, when the engine reaches a specific operating condition—such as during a high thermal load or when optimal heat recovery is desired—the thermostat signals the valve assembly to actuate. The valve assembly, which utilizes a slider-crank mechanism to convert the thermostat signal into precise mechanical movement, shifts to redirect the exhaust gases into the bypass flow path that leads directly to the heat exchanger. As the valve transitions to its closed state for the main flow path, exhaust gases are rerouted through the heat exchanger. In this mode, the D-shaped valve plate ensures a maximized effective flow area, facilitating a smooth, controlled redirection of gases. Simultaneously, the coolant absorbs the heat transferred across the plate tubes and fins, increasing in temperature as it circulates through the exchanger. The heated coolant is then channelled to serve dual purposes—it can be used for cabin heating to improve passenger comfort or for engine warmup during colder conditions, enhancing overall energy efficiency. This integrated approach—combining a robust heat exchanger design with a precise valve actuation mechanism and a responsive thermostat—demonstrates how the system overcomes traditional drawbacks. It achieves improved thermal efficiency, better pressure distribution, and greater assembly flexibility. The entire process, from exhaust gas capture to the transfer of thermal energy into usable coolant heat, illustrates a sophisticated yet practical solution for automotive heat recovery, ensuring both enhanced engine performance and improved overall vehicle efficiency.
The implementation set forth in the foregoing description do not represent all implementations consistent with the subject matter described herein. Instead, they are merely some examples consistent with aspects related to the described subject matter. Although a few variations have been described in detain above, other modifications or additions are possible. In particular, further features and/or variations can be provided in addition to those set forth herein. For example, the implementation described can be directed to various combinations and sub combinations of the disclosed features and/or combinations and sub combinations of the several further features disclosed above. In addition, the logic flows depicted in the accompany figures and/or described herein do not necessarily require the particular order shown, or sequential order, to achieve desirable results. Other implementations may be within the scope of the following claims
, C , C , Claims:1. An automotive exhaust heat recovery system (100), comprises:
a heat exchanger (200) that is connected to exhaust gas recovery pump (500) comprises:
an inlet coolant tank (202a) and an outlet tank (202b) are connected between plate tubes (206) for storing coolant;
said plate tubes (206) are adapted to transfer the coolant between the coolant tanks (202a, 202b);
cross-wave fins (204) are arranged in said plate tubes for passing the exhaust gas with cross flow path, where the coolant fluid flows through tubes/channels arranged in straight flow and exhaust gas flow in a counter cross flow direction; and
C-type air guiding baffles (208) are placed around the fin tubes;
a valve assembly (300) that is connected to a thermostat (400) for actuating the valve mechanism to control the flow of the exhaust gas, comprises:
a first valve plate (308a) that is operatively connected to a second valve plate (308b) which requires a minimum force for actuating; and
a third valve plate (308c) that is operatively connected to said second valve plate (308b) for closing the opening path of bypass exhaust gas flow path.

2. The system as claimed in claim 1, wherein the valve operates in two conditions as follow;
in open condition, said valve is opened to provide a main flow path for the exhaust gas to flow, the back side of the valve closes by-pass path outgoing flow from the heat exchanger; and
in closed condition, the valve is closed to prevent the exhaust gas flowing through the main exhaust gas flow path.

3. The system as claimed in claim 1, comprises the first valve plate (308a) in D-shape which provides an increased opening area in main flow path;

4. The system as claimed in claim 1, wherein the tapered tanks provide stabilized low-pressure distribution.

5. The system as claimed in claim 1, wherein the heat exchanger with air fins and C-type air baffles provides better heat transfer which improves the effectiveness of ~60%.

6. A method (800) for operating the exhaust heat recovery system (100), comprising:
actuating (802) the valve (308) to direct the exhaust gas flow through two paths;
directing (804) the exhaust gas in the effective main flow path (402) by valve at opening minimum force;
directing (806) the exhaust gas valve in the bypass flow path to the heat exchanger (200) by said valve (308);
capturing (808) the heat from hot exhaust gas by air fins (204);
transferring (810) heat from coolant in the plate tubes (206); and
sending (812) heat recovered coolant to the coolant outlet (202b).