FORM 2
THE PATENT ACT, 1970,
(39 OF 1970)
&
THE PATENTS RULE, 2003
COMPLETE SPECIFICATION
(SEE SECTION 10; RULE 13)
"A SYSTEM TO MINIMIZE HIGH FREQUENCY NOISE ORIGINATED FROM THE TURBOCHARGER OF AUTOMOBILES"
MAHINDRA & MAHINDRA LIMITED
AN INDIAN COMPANY,
R&D CENTER, AUTOMOTIVE SECTOR,
89, M.I.D.C., SATPUR,
NASHIK-422 007,
MAHARASHTRA, INDIA.
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED

FIELD OF INVENTION:-
The present invention relates to a noise reduction system in the charge air cooler hose in automobiles. More particularly, the present invention relates to a sound absorbing sleeve fitted over the outer circumference of the charger air cooler inlet side hose to reduce the noise of the air coming from the turbocharger.
BACKGROUND OF THE PRESENT INVENTION:-
Generally, the turbocharger is the apparatus for increasing the air volume which is inhaled by using the energy of the exhaust gas. That is, if the turbine of the turbocharger is compulsorily rotated by using the exhaust gas, while the compressor connected to turbine rotates, the air is sucked into the intake manifold. From the turbocharger, the high pressure and high temperature air is fed into the charge air cooler for cooling the engine air before it enters the engine. Since the high pressure air is coming from the turbocharger, when it passes through the base hose to the charge air cooler, it creates a whoosh noise which affects the NVH performance of the vehicle.
Attempts have been made to reduce or suppress the noise originated from the inlet hose of the charge air cooler. In a Korean patent application KR 2009074402 A, glass fibre used as the sound proof pad for the intercooler hose. Sound absorption material in this case is a low density foam or glass fiber (the flame retardant nonwoven, and the sound absorption pad) and which is wrapped by aluminum fiber.The glass fibre has its own limitations like complexity in packaging and it incurs higher cost.
The other prior art US patent application US 2011/0120584 A1 discloses a low-noise plastic intercooler pipe having a multi-layered structure including: a skin layer preferably including a thermoplastic etherester elastomer and a soundproof core layer preferably including glass bubbles. In this application thermo plastic is used along with a soundproof layer and also plastic is not suitable for higher temperature range.

In the US patent application US 2011/0073406 A1, a resonator is disclosed which includes a sleeve insert sealingly coupled to an outer duct at first and second ends of the inner sleeve. The sleeve insert has a first aperture at a first axial distance along the sleeve insert, a second aperture at a second axial distance along the sleeve insert, and a rib extending radially outwardly. The rib is located between the first and second apertures. The outer duct is also sealingly coupled to the sleeve insert at the rib. Since an acoustic silencer is added to this noise suppressing system, it can affect the pressure drop.
All the attempts which were made to suppress the whoosh noise generated from the inlet hose of the charge air cooler has many disadvantages as the type of material used in these attempts are not able to withstand at higher temperature ranges also there is too much of complexity involved manufacturing and packaging which makes these systems not economical.
To address these drawbacks of the conventional noise reduction systems, there is a need in the art to provide an economical system which reduces the whoosh noise generated in the inlet side of the turbocharger.
OBJECTS OF THE PRESENT INVENTION:-
An object of the present invention is to suppress or reduce the whoosh noise which is observed inside the passenger compartment when engine rpm rise between a speed range of 2000 and 2500 rpm.
Another object of the present invention is to provide a simple and cost effective system for suppressing the whoosh noise observed in the passenger compartment.
STATEMENT OF INVENTION:-
Accordingly the invention provides A system , to minimize high frequency noise originated from the turbocharger of automobiles due to the outside air

passing through an air filter (13) and the said a turbocharger (12), coupled to the engine (16),. with high pressure flows to a charge air cooler (15) through an IC inlet base hose (14) made of Vamac® ethylene acrylic elastomer (AEM), connecting the charge air cooler (15), to the charge the said air cooler (15, comprises providing a sleeve, made up of EPDM (Ethylene Propylene Diene Monomer) with optimized specific gravity and hardness over the said base hose to reduce the high frequency whoosh noise originated from the turbo charger, without compromising the flexibility of the base hose.
BRIEF DESCRIPTION OF THE FIGURES:-
The objects and other advantages of the present invention will become apparent when the disclosure is read in conjunction with the following figures, wherein
Figure 1 shows a schematic diagram of the present invention showing the engine, the charge air cooler, the IC inlet hose and the turbocharger;
Figure 2 shows an engine assembly with the charge air cooler inlet hose with EPDM sleeve and the turbocharger;
Figure 3 shows the perspective view of the base hose of the charge air cooler inlet with the EPDM sleeve;
Figure 4 shows the graph of the test data with whoosh noise generation pattern on different hose thickness and insulations;
DETAILED DESCRIPTION OF THE PRESENT INVENTION:-
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with the prior art techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.
The disclosed invention is about a novel sleeve on hose for a charge air cooler inlet side to minimize the high frequency noise originated from the turbocharger of an automobile engine.
According to figure 1 of the present invention, the entire engine assembly is shown along with the charge air cooler and turbocharger. The Figure 1 shows a typical layout of the engine with other accessories in an automobile. The outside air enters an air filter (13) and then the clean air flows towards a turbocharger (12) which is coupled to the engine (16). The high pressure air then flows to a charge air cooler (15) through an IC inlet base hose (14). The turbocharger (12) generates high pressure air which is passed through a base hose (14) to the charge air cooler (15). The charge air cooler (15) is made up of Aluminium alloy and the base hose (14) connecting the charge air cooler (15) and the turbocharger (12) is made of Vamac® ethylene acrylic elastomer (AEM). The sleeve is made up of EPDM (Ethylene Propylene Diene Monomer) with optimized specific gravity and hardness which is added over the base hose made of Ethylene Acrylic Elastomer, to reduce the high frequency whoosh noise originated from the turbo charger, without compromising the flexibility of the base hose.
Figure 2 shows the schematic of the engine with the charge air cooler (21) and the turbocharger (24). In this figure, the base hose (22) is completely covered with an EPDM sleeve (23) and fitted with a transition fit so that the base hose (22) will have the flexibility to oscillate due to the vibrations.
Figure 3 shows the sectional perspective view of the base hose along with the EPDM sleeve. The base hose (31) is manufactured through the extrusion process. The EPDM sleeve (32) is manufactured through the compression molding process. Manually, the EPDM sleeve (32) could not be inserted over

the base hose (31) due to the complex profile of the base hose. Hence, the tolerance values are adjusted to improve the base hose (31) assembly with no deviation on the NVH (Noise, Vibration and Harshness) performance of the assembly as well as no deterioration on the flexibility of hose. Since the charge air cooler is isolated (body mounted) from the engine, the base hose (31) is subjected to heavy vibration and oscillation movement. The EPDM sleeve (32) is not adhered to the base hose as it will restrict the movement of the hose and thus reduces its flexibility. Hence to avoid this, the EPDM sleeve (32) is inserted with transition fit instead of interference fit to get relative movement between the base hose (31) and the EPDM sleeve (32).
Figure 4 shows the test data of the base hose tested with different thickness and different insulations. The first graph shows the baseline VAMAC hose with 5 mm thickness and when the engine is throttling and reaches 3000 rpm, the graph clearly shows some black patches (41) which is the region of irritating whoosh noise. The base hose is also tested with 9.5 mm thickness and there is a marginal reduction in the whoosh noise pattern (lesser black patches) (42) during engine throttle of 3000 rpm. Since there was not much significant reduction in the whoosh noise in either of the above methods, a different method of acoustic insulation of the base hose with glass fiber wool is tested. In this there is a drastic reduction in the whoosh noise pattern (43), however this method is not economical and also there involved a lot of complex process in packaging. After a long process of material analysis, EPDM sleeve is tried over the base hose and the similar kind of whoosh noise reduction pattern (44) is seen as compared to using the glass fiber wool. In testing, it was proven that a small addition of 5mm thick EPDM sleeve on the top of the base hose gives a perceivable audible noise improvement at turbocharger.
Material Selection
As per the application requirements, it is understood that the rubber EPDM is going to serve in an atmosphere where the temperature, humidity, dust, vibration and noise would play a major role. Ethylene-propylene Diene Monomer rubbers are valuable for their excellent resistance to heat, oxidation, ozone and weather aging due to their stable, saturated polymer backbone

structure. Properly pigmented black and non-black compounds are color stable. As non-polar elastomers, they have good electrical resistivity, as well as resistance to polar solvents, such as water, alkalies, phosphate esters and many ketones and alcohols. Amorphous or low crystalline grades have excellent low temperature flexibility with glass transition points of about minus 60°C.
Heat aging resistance up to 130°C can be obtained with properly selected sulfur acceleration systems and heat resistance at 160°C can be obtained with peroxide cured compounds. Hence the peroxide cure system was selected for this process. The compression set resistance is also good, particularly at high temperatures. The rubber EPDM responds well to high filler and plasticizer loading, providing economical compounds. They can develop high tensile and tear properties, excellent abrasion resistance, as well as improved oil swell resistance and flame retardance which are required to sustain in an atmosphere where the temperature, humidity & dust plays a major role.
Best Mode
As per NVH analysis with respect to the system requirements, a hose must be in VAMAC -Ethylene Acrylate with 10 mm wall thickness to reduce the noise level by 3d'B which is not practically feasible to manufacture the hose as per required hose design without having any kind of processing issues like mounting on bend mandrel and manufacturing defects such as variation in eccentricity, surface deformation, flexibility etc. By considering these obstacles and the system surrounding temperature (100 Deg C - 120- Deg C) the rubber EPDM is selected as "Sleeve Material" to dampen the noise which is put over the VAMAC Hose. The EPDM sleeve is compounded with appropriate chemical ingredients & filler in such a way to match up the specific gravity of the VAMAC hose material in order to bring the uniformity of the matrix of two layered hose assembly to get the effect of synergized noise dampening. Though there are few rubbers which are superior in heat resistance like Silicone, Viton, the EPDM rubber is cost effective and can perform well in the said temperature range without compromising its flexibility.

Properties of Ethylene-Propylene Elastomers
Mooney Viscosity, ML 1+4 @ 125°C 5-200+
Ethylene Content, wt. % 45 to 80 wt. %
Diene Content, wt. % 0 to 15 wt. %
Specific Gravity, gm/ml 0.855-0.88 (depending on polymer composition)
Compounded EPDM -Vulcanizate properties:

Characteristics Observations
Material : EPDM
Rubber
Ash Content (%) 25.2
Specific Gravity 1.26
Original Physical Properties:
Hardness(shore A) 63
Tensile Strength (kg/cm2) 92
Elongation at Break (%) 300
Angular tear strength (kg/mm) 2.4
Heat ageing test @ 125oC * 70hrs :
Change in Hardness (Pts) +10
Change in TS (%) -1
Change in EB (%) -20
Compression set test @125°C * 22 hrs (%): 56
Ozone resistant test @10Gpphm * 40°C * 20%strain*70hrs: No Cracks
Low temperature test @-40°C * 5 hrs : No Cracks
The technical advantages achieved by the present invention are:
- This system reduces the flow induced noise at engine compartment by 2-3 dbA.

- The charge air from the turbo charger to the charge air cooler is protected from the engine compartment heat sources as the hose effective thickness now becomes 10mm.
- The hose life is relatively extended because the hose burst pressure value is increased to 24.5 bar from 13.9 bar due to the additional strength from the sleeve.
- The system meets durability life requirement of 1 lakh km of the vehicle.
It should be understood that the present invention is not to be limited by the exact details of the illustrated embodiment. However, it is to be taken as the preferred example of the invention and that various changes may be resorted to by a person skilled in the art without departing from the spirit of the invention. Also, the terminologies used herein are for the. purpose of description and should not be regarded as limiting.

WE CLAIM:-
1. A system , to minimize high frequency noise originated from the turbocharger of automobiles due to the outside air passing through an air filter (13) and the said a turbocharger (12), coupled to the engine (16),. with high pressure flows to a charge air cooler (15) through an IC inlet base hose (14) made of Vamac® ethylene acrylic elastomer (AEM) , connecting the charge air cooler (15), to the charge the said air cooler (15, comprises providing a sleeve, made up of EPDM (Ethylene Propylene Diene Monomer) with optimized specific gravity and hardness over the said base hose to reduce the high frequency whoosh noise originated from the turbo charger, without compromising the flexibility of the base hose.
2. The system as claimed in claim 1 wherein the said The EPDM sleeve (32) is manufactured through the compression molding process.
3. The method as claimed in claims 1 and 2 wherein the EPDM sleeve (32) to be inserted with transition fit instead of interference fit to get relative movement between the said base hose (31) and the said EPDM sleeve (32).
4. The system as claimed in claims 1 to 3 wherein the said EPDM sleeve is made of 5mm. thickness.
5. The system as claimed in claims 1 to 4 wherein the said sleeve made of EPDM material of 1.26 specific gravity .hardness 63 shore A, and tensile strength 92 kg/ cm2.