A sealing device which is used to seal a leak test aperture in an ECU. The sealing device is selectively disposed in the leak test aperture, and an inner surface is formed as part of the leak test aperture. The sealing device has a first portion, and a second portion connected to the first portion. The sealing device is press-fitted into the leak aperture such that the first portion is in contact with the inner surface, securing the position of the sealing device in the leak test aperture, and the second portion is also in contact with the inner surface to prevent moisture and debris from passing through the leak test aperture. The second diameter is larger than the first diameter such that the second diameter of the second portion applies a pressure to the inner surface of the leak test aperture, forming a seal.

FIELD OF THE INVENTION

Embodiments of the invention relate to a sealing device for sealing a leak test aperture formed as part of a housing of an engine controller.

BACKGROUND OF THE INVENTION

An Electronic Control Unit (ECU) is used in many different types of vehicles to provide control over the operation of various components. The ECU is used to control various actuators which are part of an engine to optimize the operation of the engine. The ECU controls air-fuel mixture, ignition timing, idle speed, and in some more advanced versions of an ECU, variable valve timing, transient fueling, maximum RPM, and the like, are also controlled by the ECU.

The ECU is often required to function in a harsh environment, where the ECU may be exposed to different temperatures, as well as moisture. The ECU includes a cover which is part of a casing, and after assembly, the casing is tested for leaks to make sure that no moisture or debris is able to enter into the casing and damage any internal components. One type of approach to test the ECU for leaks is to force pressurized air into an aperture formed as part of the cover, referred to as a “leak test aperture,” and determine if any air leaks out of the casing. Once the test is complete, a seal is deposited into the aperture.

However, current seals used in leak test apertures do not adequately provide assurance that the leak test aperture is sealed. Some of these seals do not provide an adequate sealing function due to die casting surface irregularities in the leak test aperture. Also, the location of the seal in the leak test aperture may not always be known once the ECU is assembled, making it difficult to determine whether the leak test aperture is in fact sealed.

Accordingly, there exists a need for an improved sealing of a leak test aperture once the assembly of the ECU is completed.

SUMMARY OF THE INVENTION

The present invention is a sealing device which is used to seal a leak test aperture in an ECU. In one embodiment, the present invention is an assembly for sealing an aperture, which includes a sealing device selectively disposed in a leak test aperture having an inner surface. The sealing device has a first portion and a second portion connected to the first portion. The first portion of the sealing device has a first diameter, and the second portion has a second diameter. The sealing device is press-fitted into the leak aperture such that the first diameter is in contact with the inner surface, securing the position of the sealing device in the leak test aperture.

When the sealing device is disposed in the leak test aperture, the second diameter is also in contact with the inner surface to prevent moisture and debris from passing through the leak test aperture. The second diameter is larger than the first diameter such that the second diameter of the second portion applies a pressure to the inner surface of the leak test aperture, forming a seal.

In one embodiment, a tapered portion is formed as part of the second portion such that the tapered portion is smaller than the second diameter, and a lower diameter is formed as part of the leak test aperture. The tapered portion is disposed in the lower diameter of the leak test aperture when the sealing device is disposed in the leak test aperture.

The first portion is made of metal, such as steel or aluminum, and the second portion is made of a sealing material, such as silicone rubber (VMQ), acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), ethylene propylene diene rubber (EPDM), other types of synthetic rubber, and the like.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A cover which is used with an overmolded sealing device according to the present invention is shown inFIGS. 1-3generally at10. The cover10includes a leak test aperture12, and several assembly apertures14which are used for connecting the cover10to the rest of a housing (not shown) of an electronic control unit (ECU). Selectively disposed in the leak test aperture12is a sealing device, shown generally at16inFIGS. 3-4. The sealing device16includes a first portion18and a second portion20. The first portion18is made of metal, such as steel, and the second portion20is made of a sealing material, which in this embodiment is silicone rubber (VMQ). However, it is within the scope of the invention that other types of materials may be used, such as acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), ethylene propylene diene rubber (EPDM), other types of synthetic rubber, and the like.

The first portion18is substantially cylindrical in shape, but may be other shapes to correspond to the shape of different leak test apertures in different covers. The second portion20is also substantially cylindrical in shape, but is flexible to contact the inner surface22of the aperture12. During assembly, the device16is press-fitted into the aperture12using the first portion18, and is held in place by the first portion contacting the inner surface22because of the press-fit. The aperture12has an upper diameter22A, which is sized to allow for a press-fit of the device16.

In the embodiment of the sealing device16shown inFIG. 4, the first portion18has a first diameter24, and the second portion20has a second diameter26, which in this embodiment is larger than the first diameter24to provide an adequate seal. The second portion20shown inFIG. 4has a varying diameter, and the second diameter26is the largest diameter of the second portion20. However, it is within the scope of the invention that other size diameters for both the first portion18and the second portion20may be used.

When the device16is press-fitted into the aperture12, the first diameter24of the first portion18contacts the inner surface22of the aperture12, maintaining the position of the device16in the aperture12. The second portion20is also pressed against the inner surface22of the aperture12, providing a sealing function. The second diameter26is large enough such that the second portion20applies pressure to the inner surface22, creating a seal, preventing moisture or debris from passing through the aperture12, and entering into the housing.

Another embodiment of the sealing device16is shown inFIGS. 5-7. In this embodiment, the second portion20not only has the second diameter26, but a part of the second portion20has a tapered portion28, where the widest diameter portion32of the tapered portion28is less than the second diameter26. The tapered portion28tapers at an angle 38. The size of the angle38may vary, depending upon the desired shape of the tapered portion28. Additionally, the tapered portion28has a thickness42between an end surface40and the widest part of the widest diameter portion28. The thickness42may vary, depending upon the size of the tapered portion28and the size of the second portion20which is desired.

The sealing device16shown inFIGS. 5-7is suitable for use with a leak test aperture12having a lower diameter22B. When the sealing device16is press-fitted into the aperture12, the first diameter portion18contacts the inner surface22of the aperture12to maintain the position of the device16in the aperture12, and the second portion20also contacts the inner surface22of the aperture12to provide a sealing function. However, the part of the second portion20that has the tapered portion28extends into the lower diameter22B, to provide further sealing. The lower diameter22B also reduces the risk that moisture and debris could enter the housing through the leak test aperture12.

Another type of cover10is shown inFIG. 8, where the cover10is used for a different type of housing. The cover10shown inFIG. 8is used with the embodiment of the sealing device16shown inFIG. 6. In this embodiment, the cover10also includes a leak test aperture12, but the leak test aperture12has a cylindrical sidewall36which extends outwardly away from the cover10. The leak test aperture12in this embodiment also has an upper diameter22A and a lower diameter22B. When assembled, the sealing device16is press-fitted into the aperture12, and the second portion20contacts the upper diameter22A, and the tapered portion28is disposed in the lower diameter22B. The first portion18, second portion20, and tapered portion28may be shaped to fit into differently shaped leak test apertures, making the sealing device16suitable for different applications.

In one embodiment, the first portion18and the second portion20are connected together through the use of an adhesive34. However, in other embodiments, the portions18,20may be connected together in different ways. A combination of different shapes of the first portion18and second portion20may provide for a connection such as an interference fit between the first portion18and the second portion20. For example, the first portion18may have a protrusion with a hook or flange that is received into a complementary-shaped recess formed as part of the second portion20, or vice versa, providing an interference fit connection between the two portions18,20.