Claims:We claim:

1. An integrated dual stage and dual medium exhaust gas recirculation (EGR) cooling system for diesel engines, wherein the EGR cooling system comprises:

(a) an intake manifold disposed downstream a venturi pipe for mixing filtered atmospheric air supplied to it from an air filter with cooled EGR and supplying air-EGR mixture to diesel engine for combustion therein;

(b) an EGR valve controller housing;

(c) a thermostat housing; and

(d) an air fan coupled to a coolant pump;

wherein EGR is cooled in a dual stage cooling arrangement by passing it first through the EGR valve controller housing and then through the thermostat housing and finally by forced air circulation generated by engine cooling fan, for cooling hot EGR to recover EGR heat energy for enhancing the engine performance.

2. Integrated dual stage and dual medium EGR cooling system as claimed in claim 1, wherein EGR valve controller housing comprises an exhaust gas (EGR) core and a coolant core for heat exchange therebetween for cooling hot EGR received from the exhaust manifold of the diesel engine by means of the engine coolant passed through the EGR valve controller housing for recovery of a portion of EGR heat energy.

3. Integrated dual stage and dual medium EGR cooling system as claimed in claim 1, wherein thermostat housing comprises an exhaust gas (EGR) core and a coolant core for heat exchange therebetween for cooling hot EGR received from the exhaust manifold of the diesel engine by means of the engine coolant passed through the thermostat housing for recovery of another portion of EGR heat energy.
4. Integrated dual stage and dual medium EGR cooling system as claimed in claim 3, wherein the exhaust gas (EGR) core of the EGR valve controller housing is the first exhaust gas (EGR) core and is disposed downstream the exhaust manifold of diesel engine for directly receiving hot EGR therefrom for cooling thereof to recover substantial portion of the heat energy contained therein.

5. Integrated dual stage and dual medium EGR cooling system as claimed in claim 3, wherein the coolant core of the thermostat housing is the first coolant core and is disposed downstream the diesel engine for receiving engine coolant therefrom for cooling the initially cooled exhaust gas (EGR) received from the first exhaust gas (EGR) core to recover a portion of the heat energy contained therein.

6. Integrated dual stage and dual medium EGR cooling system as claimed in claim 3, wherein the exhaust gas (EGR) core of the thermostat housing is the second exhaust gas (EGR) core disposed downstream the first exhaust gas (EGR) core of the EGR valve controller housing for further cooling of the EGR.

7. Integrated dual stage and dual medium EGR cooling system as claimed in claim 3, wherein the coolant core of the thermostat housing is the second coolant core disposed downstream the first coolant core of the thermostat housing for further cooling of the EGR.

8. Integrated dual stage and dual medium EGR cooling system as claimed in claim 6, wherein the EGR gas received from the second exhaust gas (EGR) core is further cooled by means of forced air circulation generated by the engine cooling fan.

9. Integrated dual stage and dual medium EGR cooling system as claimed in claim 8, wherein the further cooled EGR gas after cooling by means of forced air circulation are passed around venturi pipe for preheating air supplied to the air intake manifold and for further recovery of the heat energy contained in the EGR.
10. Integrated dual stage and dual medium EGR cooling system as claimed in claim 7, wherein the hot coolant received from the second coolant core is merged with the main coolant supply received through the coolant pump inlet.

11. Integrated dual stage and dual medium EGR cooling system as claimed in claim 1, wherein the EGR valve controller housing accommodated an EGR valve controller to receives signals from the ECU and to forward the same via the thermostat housing to the venturi pipe for providing a predetermined quantity of filtered air to the intake manifold of the diesel engine for combustion therein.

12. A method for cooling hot EGR of the diesel engine by means of integrated dual stage and dual medium exhaust gas recirculation (EGR) cooling system, the method comprises the steps of:

• receiving the hot EGR directly from the exhaust manifold of the diesel engine;

• cooling the said hot EGR in the first exhaust gas (EGR) core by means of the coolant received from the second coolant core;

• cooling further the EGR received from the first exhaust gas (EGR) core by means of the coolant in the first coolant core;

• cooling still further the EGR received from the second exhaust gas (EGR) core by means of a forced air circulation generated by the engine cooling fan;

• final cooling of the EGR around the venturi pipe by preheating the air supplied to the air intake manifold of the diesel engine; and

• acceleration of the convective heat transfer by cooling fan;

wherein the coolant is progressively heated by energy received from the hot EGR first in the thermostat housing, then in the EGR valve controller housing and the heated coolant leaving the same is merged with the main coolant supply to the coolant pump.

Dated: this 02nd day of August 2017. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT , Description:FIELD OF INVENTION

The present invention relates to an integrated exhaust gas recirculation (EGR) system for diesel engines. In particular, the present invention relates to an integrated dual-stage & medium EGR cooling system for diesel engines. More particularly, the present invention relates to an integrated dual-stage and dual medium (coolant and forced air from fan) EGR cooling system for diesel engines provided on EGR valve and thermostat housing thereof. The present invention relates to the method for cooling EGR by this system.

BACKGROUND OF THE INVENTION

The TIER Standards are the federal (US) standards for new nonroad (or off-road, e.g. tractors) diesel engines adopted in 1994 as TIER 1 standards for engines over 37 kW or 50 HP which were phased-in from 1996 to 2000. A Statement of Principles (SOP) pertaining to such nonroad diesel engines was signed in 1996, between the EPA, California ARB and engine makers worldwide, including Caterpillar, Cummins, Deere, Detroit Diesel, Deutz, Isuzu, Komatsu, Kubota, Mitsubishi, Navistar, New Holland, Wis-Con, and Yanmar. The EPA signed the final rule reflecting the provisions of the SOP in 1998 for introducing the regulation as TIER 1 standards for equipment under 37 kW or 50 HP and successively made it more stringent by introducing TIER 2 and TIER 3 standards for all equipment with phase-in schedules from 2000 to 2008. The Tier 1-3 standards were implemented through advanced engine design, without or only limited use of exhaust gas after-treatment, i.e. oxidation catalysts. TIER 3 standards for NOx+HC were equally stringent to the 2004 standards for highway engines, its standards for particulate matters (PM) were never adopted.

The final TIER 4 Standards were signed and introduced by the EPA on May 11, 2004, which were phased-in over the period of 2008-2015. The TIER 4 standards require that emissions of PM and NOx be further reduced by about 90%. Such emission reductions can only be achieved by using control technologies - including advanced exhaust gas after-treatment, similar to those required by the 2007-2010 standards for highway engines.
Since at TIER 1-3 stages, the sulfur content in nonroad diesel fuels nonroad Diesel Fuel was not limited by environmental regulations, the oil industry specification of 0.5% (wt., max), with the average in-use sulfur level of about 0.3% = 3,000 ppm was made stringent by enabling sulfur-sensitive control technologies in TIER 4 engines, these included catalytic particulate filters (DPF) and NOx adsorbers. The EPA mandated the following reductions in sulfur content in nonroad diesel fuels:

• Diesel fuels to have 500 ppm w.e.f. June 2007 for nonroad, locomotive and marine (NRLM).

• Diesel fuels to have 15 ppm (ultra-low sulfur diesel) w.e.f. June 2010 for nonroad fuel, and w.e.f. June 2012 for locomotive and marine diesel fuels.

Accordingly, under TIER-4 standards, the exhaust gas recirculation (EGR) is widely used to reduce the NOx formation during combustion. Cooling of exhaust gas improves the efficiency. EGR system facilitates the recovery and utilization of some of the heat normally wasted through exhaust gas and also cools it before releasing to the atmosphere for enhanced environmental protection under TIER-4 application.

DISADVANTAGES WITH THE PRIOR ART

The disadvantages with the conventional EGR cooling system of diesel engines discussed above are that EGR cooler is a standalone proprietary unit provided by the supplier. It is quite cumbersome and complicated to integrate a proprietary EGR cooler unit to the diesel engine. EGR controller is also prone to be less efficient due to high temperatures. Substantial energy is wasted in the form of exhaust gases, which are lost to atmosphere and also raise emission issues.

Therefore, there is an existing need for providing an EGR cooling arrangement to safeguard EGR controller from high temperatures, reduce gritty carbon/lacquer formations on EGR controller’s valve seat area as well as to save time, cost and to facilitate in a simpler layout and to improve the overall engine performance by a quicker warm-up thereof and by reducing EGR cooler servicing.
OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a cost-effective exhaust gas cooling system on EGR valve housing as well as thermostat housing passage.

Another object of the present invention is to provide an exhaust gas cooling system for cooling regular engine parts both by engine coolant and forced air circulation.

Still another object of the present invention is to provide an exhaust gas cooling system which is easy for maintenance and servicing thereof.

Yet another object of the present invention is to provide an exhaust gas cooling system of modular construction to be integrated to the existing diesel engines.

A further object of the present invention is to provide an exhaust gas cooling system not requiring any separate cooling arrangement for EGR controller.

A still further object of the present invention is to provide an exhaust gas cooling system which facilitates a hassle-free diesel engine operation and performance throughout service-life thereof.

A yet further object of the present invention is to provide an exhaust gas cooling system which is not a field irritant and easily earns customer satisfaction.

An additional object of the present invention is to provide an exhaust gas cooling system and ensuring uniform mixing of fresh air to exhaust gas in an intake venturi.

One more object of the present invention is to provide a method for controlling / cooling exhaust gas of an internal combustion diesel engine.
These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided an integrated dual stage and dual medium exhaust gas recirculation (EGR) cooling system for diesel engines, wherein the EGR cooling system comprises:

(a) an intake manifold disposed downstream a venturi pipe for mixing filtered atmospheric air supplied to it from an air filter with cooled EGR and supplying air-EGR mixture to diesel engine for combustion therein;

(b) an EGR valve controller housing;

(c) a thermostat housing; and

(d) an air fan coupled to a coolant pump;

wherein EGR is cooled in a dual stage cooling arrangement by passing it first through the EGR valve controller housing and then through the thermostat housing and finally by forced air circulation generated by engine cooling fan, for cooling hot EGR to recover EGR heat energy for enhancing engine performance.

Typically, the EGR valve controller housing comprises an exhaust gas (EGR) core and a coolant core for heat exchange therebetween for cooling hot EGR received from the exhaust manifold of the diesel engine by means of the engine coolant passed through the EGR valve controller housing for recovery of a portion of EGR heat energy.

Typically, the thermostat housing comprises an exhaust gas (EGR) core and a coolant core for heat exchange therebetween for cooling hot EGR received from the exhaust manifold of the diesel engine by means of the engine coolant passed through the thermostat housing for recovery of another portion of EGR heat energy.
Typically, the exhaust gas (EGR) core of the EGR valve controller housing is the first exhaust gas (EGR) core and is disposed downstream the exhaust manifold of diesel engine for directly receiving hot EGR therefrom for cooling thereof to recover substantial portion of the heat energy contained therein.

Typically, the coolant core of the thermostat housing is the first coolant core and is disposed downstream the diesel engine for receiving engine coolant therefrom for cooling the initially cooled exhaust gas (EGR) received from the first exhaust gas (EGR) core to recover a portion of the heat energy contained therein.

Typically, the exhaust gas (EGR) core of the thermostat housing is the second exhaust gas (EGR) core disposed downstream the first exhaust gas (EGR) core of the EGR valve controller housing for further cooling of the EGR.

Typically, the coolant core of the thermostat housing is the second coolant core disposed downstream the first coolant core of the thermostat housing for further cooling of the EGR.

Typically, the EGR gas received from the second exhaust gas (EGR) core is further cooled by means of forced air circulation generated by the engine cooling fan.

Typically, the further cooled EGR gas after cooling by means of forced air circulation are passed around venturi pipe for preheating air supplied to the air intake manifold and for further recovery of the heat energy contained in the EGR.

Typically, the hot coolant received from the second coolant core is merged with the main coolant supply received through the coolant pump inlet.

Typically, the EGR valve controller housing accommodated an EGR valve controller to receives signals from the ECU and to forward the same via the thermostat housing to the venturi pipe for providing a predetermined quantity of filtered air to the intake manifold of the diesel engine for combustion therein.

In accordance with the present invention, there is also provided a method for cooling hot EGR of the diesel engine by means of integrated dual stage and dual medium exhaust gas recirculation (EGR) cooling system, the method comprises the steps of:

• receiving the hot EGR directly from the exhaust manifold of the diesel engine;

• cooling the said hot EGR in the first exhaust gas (EGR) core by means of the coolant received from the second coolant core;

• cooling further the EGR received from the first exhaust gas (EGR) core by means of the coolant in the first coolant core;

• cooling still further the EGR received from the second exhaust gas (EGR) core by means of a forced air circulation generated by the engine cooling fan;

• final cooling of the EGR around the venturi pipe by preheating the air supplied to the air intake manifold of the diesel engine; and

• acceleration of the convective heat transfer by cooling fan;

wherein the coolant is progressively heated by energy received from the hot EGR first in the thermostat housing, then in the EGR valve controller housing and the heated coolant leaving the same is merged with the mail coolant supply to the coolant pump.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, wherein:

Figure 1 shows a schematic view of the conventional system 50 for a diesel engine equipped with an EGR cooler.

Figure 2 shows a detailed top view of the conventional system of Fig.1.

Figure 3 shows a detailed exploded view of the conventional system of Fig.1.
Figure 4 shows a schematic view of the integrated EGR cooling system for a diesel engine without a dedicated EGR cooler.

Figure 5 shows a detailed top view of the integrated EGR cooling system configured in accordance with the present invention of Fig.4.

Figure 6 shows a perspective view of the integrated system of Fig.5.

Figure 7 shows a perspective view of the intake manifold and exhaust manifold of the integrated system of Fig.5.

Figure 8a shows a perspective front view of the EGR housing connected to the coolant passages and exhaust pipes of the integrated system of Fig.5.

Figure 8b shows a perspective rear view of the EGR housing connected to the coolant passages and exhaust pipes of the integrated system of Fig.5.

Figure 8c shows a perspective view of the exhaust pipe of the system of Fig.5.

Figure 8d shows a perspective front view of the coolant passages of the system of Fig.5.

Figure 8e shows a graphical representation of the Convective Heat Transfer Coefficient with the change in the air velocity.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, the EGR system configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows a schematic view of the conventional system 50 for a diesel engine equipped with an EGR cooler. The system includes a diesel engine 12, an intake manifold 14, an EGR cooler 16, an EGR controller 18, EGR coolant inlet 20, EGR coolant outlet 22, atmospheric air 24 being filtered by an air filter 26, a mixing pipe 28, an exhaust manifold 30, an EGR recirculation pipe 32, an air fan 34, a coolant pump 36 with coolant inlet 38, a thermostat 40 with a coolant outlet 42, a diesel oxidation catalyst (D.O.C.) 44, a muffler with a tail pipe 46 releasing exhaust gas 48 to the atmosphere.

Figure 2 shows a detailed top view of the conventional system of Figure 1 using an air fan for sucking atmospheric air used for cooling the entire engine area.

Figure 3 shows a detailed exploded view of the conventional system of Fig. 1 comprising a EGR cooler 16 of shell and tube construction. It includes a plurality of exhaust gas separation tubes 152 made of stainless steel disposed inside a cylindrical shell 154 cooled by engine coolant entering from one side 156 and existing from the other side 158 thereof. The EGR cooler 16 is mounted via a respective flange 162, 164 on either side of the cylindrical cooling shell 154 and hot exhaust gas 166 entering from one side and cooled exhaust gas 168 exiting from the other side thereof. Here, the EGR cooler 16 works as a counter-flow type of heat exchanger.

Figure 4 shows a schematic view of the integrated system exhaust gas cooling system 150 for a diesel engine without a dedicated EGR cooler. The system 150 includes a diesel engine 112, an intake manifold 114, atmospheric air 124 sucked into an air filter 126 and fed via a VENTURI 128 for providing air supply to the intake manifold 114, an EGR controller 115 fitted in a housing 118 which receives an ECU signal 120 and forwards the same via a thermostat housing 140 to the VENTURI 128. An air fan 134 for providing a forced air circulation of the atmospheric air 124. The air fan 134 is coupled to a coolant pump 136 having an engine coolant inlet 138. The coolant pump 136 is also connected to a thermostat housing 140 through which engine coolant 121 is fed to the EGR controller housing 118 for cooling thereof and subsequently this engine coolant 122 is merged with the coolant supply through inlet 138 of the coolant pump 136. The hot exhaust gas exiting the diesel engine 112 is supplied first to the EGR controller housing 118, then partially cooled EGR is led further to the thermostat housing 140 and subsequently to the venturi 128 and this cooled exhaust gas is finally added there to the atmospheric air 124 to be fed to the intake manifold 114 for enhancing the EGR cooling efficiency of the diesel engine 112. With this system configuration, heat/energy wasted in the engine exhaust is recovered.

Figure 5 shows a detailed top view of the integrated EGR cooling system configured in accordance with the present invention of Figure 4. It includes an exhaust manifold 130, an EGR controller housing 118 including a coolant core 117 and an exhaust gas core 119, an EGR controller 115, a thermostat housing 140 also including a coolant core 141 and an exhaust gas core 143, thermostat cover 142, an engine cooling fan 134, a coolant pump 136, an EGR pipe 132, an intake venturi 128, an intake manifold 114, coolant inlet pipes/hoses 111, coolant outlet pipes/hoses 113.

Figure 6 shows a perspective view of the integrated system of Figure 5.

Figure 7 shows a perspective view of EGR controller housing 118 of the integrated system 150 of Figure 5. The EGR controller housing 118 consists of a coolant core 117 and an exhaust gas core 119 and the thermostat housing 140 consists of a coolant core 141 and an exhaust gas core 143.

Figure 8a shows a perspective view of the EGR housing 118 connected to the coolant passages 113 and exhaust pipe 132 of the integrated system of Figure 5. EGR housing 118 has exhaust gas pipe 132 having an EGR inlet 131 provided at the EGR housing 118 and an EGR outlet 133 at the other end thereof. EGR housing 118 is being cooled by means of an engine coolant 121 passed through the coolant passage having a coolant inlet 117 and a first coolant outlet 119 connected to a coolant pump 136 (not shown here) and a second coolant outlet 123 to the radiator (not shown here).

Figure 8b shows a perspective rear view of the EGR housing 118 connected to the coolant passage 113, an exhaust gas core 143 and exhaust pipe 132 of the integrated system of Figure 5 and clearly illustrating the second coolant outlet 123 to the radiator (not shown here).

Figure 8c shows a perspective view of the exhaust pipe 132 of the integrated system connected to the EGR housing 118 and having an EGR inlet 131 and an EGR outlet 133 at either ends thereof.

Figure 8d shows a perspective front view of the coolant passages of the integrated system 150 of Figure 5. It illustrates engine coolant 121 entering through a coolant inlet 117 and passed through the coolant passage having a first coolant outlet 119 connected to a coolant pump 136 (not shown here) and a second coolant outlet 123 to the radiator (not shown here). The location 115 of the EGR housing 118 (removed here) is also shown here.

Figure 8e shows a graphical representation of the Convective Heat Transfer Coefficient with the change in the air velocity. This coefficient continuously increases from air-velocity 2 m/sec and at 20 m/sec it is constant.

WORKING OF THE INVENTION

The dual-stage and dual-medium EGR cooling system configured in accordance with the present invention facilitates in the recovery and utilization of the waste heat and energy of the hot exhaust gas generated inside the diesel engine for TIER-4 applications, such as farm tractors, excavators, bulldozers, wheel/backhoe loaders, road graders etc. This EGR cooling system comprises exhaust gas cooling in the EGR valve controller housing and thermostat housing by using engine coolant. The exhaust gas is further cooled by using forced air circulation generated by the engine cooling fan. This gradual cooling of the exhaust gas substantially increases the engine performance. This dual-stage EGR cooling arrangement also safeguards the EGR controller from high temperatures to which it is normally exposed.

Usually EGR cooler is standalone part from proprietary supplier. Integrating the same in engine is cumbersome and complicated. By the new configuration in accordance with the present invention, substantial time and money can be saved and the lay-outing is made simple and simultaneously the engine performance is met suitably.
The dual-stage system by integrating the exhaust gas cooling by using engine coolant for cooling EGR valve controller housing and thermostat housing and by passing forced air over the integrated system partially utilizes waste heat energy of the engine, otherwise lost by releasing hot exhaust gas to atmosphere, which energy is used heat the engine in shorter time and thus engine quick warm-up is achieved to improve the engine efficiency.

This new configuration also eliminates the EGR cooler servicing and formation of gritty carbon on EGR controller valve seat area and EGR controller mechanism.
The objects of the present invention also include achieving the following values:

a) EGR Valve flange max temperature < 2000C
b) EGR Stem temperature < 3000C
c) Poppet Valve Temperature < 5000C

CFD Modelling:

I. A virtual simulation (Natural Convection) was also carried out with the following boundary conditions:

• Exhaust Gas flow rate at manifold inlet = 155 kg/hr.
• EGR flow rate (from Exhaust Manifold) = 20 kg/hr.
• Back pressure due to cold end of exhaust system = 150 mbar.
• Pressure drop across substrate is 22.47 mbar for flow-rate of 135 kg/hr.
• Coolant Inlet flow rate from Cylinder Head Outlet = 75 LPM.
• Coolant flow rate to radiator = 55 LPM.
• Coolant Outlet pressure (near Coolant Pump Inlet) = 800 mbar.
• Exhaust Gas temperature at manifold inlet = 6000C.
• Coolant Inlet temperature at Cylinder Head Outlet = 1060C.

The above simulation is carried out by assuming that:

• Heat transfer due to surrounding components is not considered.
• Instead of Exhaust gas, Air is considered flow medium inside EGR pipe.
• Air temperature between EGR pipe and heat shield is 1500C and HTC is 10 W/m2-K.
• Surrounding air temperature is taken as 850C and HTC is 15 W/m2-K.

The targets are:

- EGR valve flange maximum temperature of < 2000C.
- EGR Stem temperature < 3000C.
- Poppet valve temperature < 5000C.

RESULTS:
Natural Convection

1) The observed pressure-drop across EGR passage (Fig.8c) and coolant passage (Fig.8d) is 115.2 mbar and 278.6 mbar respectively.

2) The observed net surface temperature-drop across EGR passage (Fig.8c) is 237.70C and net temperature rise across the coolant passage (Fig.8d) is 0.830C. Accordingly, the outgoing EGR gas temperature is 328.50C and the heated coolant temperature is 106.830C.

3) The maximum temperature on the valve flange is 1450C, the maximum EGR stem temperature is 1900C and the maximum temperature on the poppet valve is 5350C.

4) Similarly, when the engine coolant is not flowing through the thermostat housing, the observed temperature-drop across EGR passage is 191.20C and the maximum temperature rise across coolant passage is 0.770C. Accordingly, the outgoing EGR gas temperature is 375.70C and the heated coolant temperature is 106.770C.

5) There is also a maximum temperature-drop of 46.50C observed in the thermostat housing.

II. A virtual simulation (Forced Convection by a cooling fan)

No change in the model
The above simulation is carried out by assuming that the exhaust flow rate and temperature changes with change in engine rpm.

Only convective boundary condition was modified based on the air velocity (please see Figure 8f). For example:

Case No. Engine Speed
(rpm) Air velocity
(m/sec) Max. temperature
(0C) Convective Heat Transfer Coefficient (W/m2-K)
1 1000 2.0 - 2.5 144.7 18
2 1400 3.0 - 3.5 144.6 20
3 2600 6.0 - 6.5 144.4 28

However, max. temperature is maintained constant for above CFD modelling.

RESULTS:
Forced Air-Circulation

Very small differences in the surface or skin temperatures of EGR, Thermostat Housing and EGR Valve is observed for given air flow velocities. The reason being the contributions of the coolant for cooling the housings and EGR Valve are significantly higher than the ambient air. However, with this new arrangement, the heat transfer can be quickly accelerated to cool both the exhaust gas and the coolant to some extent.

RESULTS:
At Dynamometer

With this new configuration, the engine (35 HP @ 2500 rpm) performance was tested at 250C ambient temperature and the following results were obtained:

Result of: Engine Speed (rpm) Exhaust Temperature (0C) Exhaust
Back-pressure (mbar) EGR
Valve Housing Temperature (0C) Temperature
after Thermostat Housing (0C)
Test 2500 567 120 295 260
Simulation 2500 570 150 416 375

Accordingly, it was observed that there is a relative correlation of the temperature drop between the EGR housing area and the thermostat region. The above test results show a higher temperature drop across the integrated cooling housings.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The integrated dual-stage/medium exhaust gas cooling system configured in accordance with the present invention has the following technical and economic advantages:

1. Cost effective solution.

2. Easy to maintain and service.

3. Modular design.

4. Simple system for integrating.

5. Separate cooling arrangement for EGR controller is not required for temperature protection.

6. Low cost since passages are integrated in housings.

7. Not required to service due to elimination of EGR cooler.

8. Hassle free engine operation and performance throughout engine life.

9. No field irritant and customer satisfaction

The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention. The description provided herein is purely by way of example and illustration.

Although, the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification by making innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention.

These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art and they will not therefore be discussed in significant detail.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.
The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

Also, any reference herein to the terms ‘left’ or ‘right, ‘up’ or ‘down, or ‘top’ or ‘bottom’ are used as a matter of mere convenience, and are determined by standing at the rear of the machine facing in its normal direction of travel.

Furthermore, the various components shown or described herein for any specific application of this invention can be widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. When referring to the figures, like parts are numbered the same in all of the figures.