Arrangement for Mounting Electronic Circuit Boards on an Engine-Air Intake Structure

This invention relates to a novel arrangement for mounting electronic circuit components in the engine compartment of a vehicle and in particular to a novel arrangement for mounting the circuit boards on the engine air filter housing.

Among the features and objects of the present invention are to provide an improved mounting arrangement for electronic circuit boards containing engine control circuitry: which can be easily assembled into and disassembled from an engine air filter housing; in which the circuit components are well protected; in which the circuit components are exposed to cooling via the induction air drawn into the air filter housing; which provides easy connectability with system components located outside the air filter housing; which provides an advantageous construction; and which offers other benefits and advantages as will appear more fully hereinafter in the detailed description.

The drawing illustrates a preferred embodiment of the present invention according to the best mode presently contemplated in carrying out the invention.

FIG. 1 is a plan view having portions broken away of an arrangement for mounting electronic circuit boards on the engine air filter housing according to principles of the present invention.

FIG. 2 is a longitudinal sectional view through the arrangement of FIG. 1.

The drawing illustrates a sheet metal air filter housing 10 of generally cylindrical shape, a cylindrical annular air filter 12 contained within housing 10, a plastic circuit board mounting housing 14 and a moulded plastic intake snorkel 16. Housing 10 and filter 12 are generally of conventional construction and mount on the engine in the usual fashion; however, in accordance with principles of the present invention certain modifications may be made to the housing 10 which include the provision of one or more openings 18 formed in the side wall of the housing, a plurality of attaching brackets 20 for attachment of circuit board housing 14, and the height of the side wall of the housing 10 may be somewhat increased. The cover for housing 10 has not been shown in the drawing in the interest of clarity.

Housing 14 is of generally concave shape extending circumferentially of housing 10 and disposed over the openings 18. Housing 14 attaches to housing 10 by means of attachment screws 22 which are threaded into brackets 20. An annular sealing gasket 24 seals between the two housings and is compressed to a limited extent when the screws 22 are tightened to draw the housing 14 against housing 10. A leak-proof seal is attained by providing a plurality of individual protuberances such as 26 at locations around the inner edges of the upper and lower walls of housing 14. With this arrangement, when the screws 22 are tightened the gasket 24 will be controllably compressed with the compression thereof being limited by the protuberances 26 abutting the wall of the air filter housing 10. A continuous backup flange 28 is provided for gasket 24. The radially outer edge of housing 14 terminates in an opening over which snorkel 16 is disposed. Snorkel 16 is a tubular element and its inner periphery is provided with a flange which abuts the radially outer periphery of housing 14 and the two elements 14 and 16 are secured together by any suitable securing means. Desirably, a sealing gasket 30 may be provided between the two. When the engine is operated induction air is drawn through snorkel 16 and housing 14, through openings 18 and through air filter 12 into the engine carburetor to be mixed with fuel for combustion in the engine.

The invention provides within housing 14 the mounting of electronic circuitry which is associated with a control system for the engine, for example electronic fuel metering controls, electronic spark timing controls, or electronic fuel injection controls. The circuitry in the illustrated embodiment is contained in a number of individual electronic circuit modules 32 of the plug-in type which plug into electronic circuit boards 34 which are removably secured within housing 14. The two circuit boards 34 are removably mounted on housing 14 by means of attaching screws 36 which pass through openings in the boards to engage threadedly threaded holes in molded structural ribs 38' which are integrally formed in housing 14. The modules 32 removably mount on boards 34 by means of plug-in type terminals. The modules 32 may contain individual electronic circuit boards 38 having individual circuit components thereon, the boards 38 being potted by means of suitable potting material within sheet metal receptacles 40. Lead wires from the circuit boards 34 terminate in connector plugs 42 which mount in the bottom wall of housing 14. Plugs 42 are mateable with matching connector plugs (not shown) to effect connection of the circuits on the boards with additional portions of the system which are located exteriorly of housing 14. Internal connections between the individual modules and circuit boards can be accomplished by internal connections. The location of modules 32 within housing 14 is such that adequate clearance is provided to permit induction air to pass freely into the engine without appreciable obstruction while at the same time exposing the circuit components to the conductive cooling afforded by the induction air. Thus, even in the hot environment of an underhood engine compartment, the electronic circuit components can be maintained in a thermal environment which is not detrimental to the circuit components. A further system component 44 is shown disposed on snorkel 16 and extending through an opening in the snorkel to be disposed in the path of travel of the induction air. This element could be any of a number of possible devices and is illustratively shown as a probe for monitoring the velocity of intake air flow through snorkel 16. An electronic circuit module 46 is contained in association with element 44 within a cover 48 which mounts on snorkel 16.

The invention provides an advantageous mounting arrangement for circuit components which excellently accomplishes the above-noted features. It will be appreciated that various configurations are contemplated within the scope of the invention and that the preferred embodiment is to be considered in an illustrative and not a limiting sense.