Engine Block Mount

The invention relates to the front end body structure of motor vehicles, and more particularly to the mounting of engines.

Automobile frame and body designs have taken into account the need for absorbing the impact of frontal collisions. To this end, U.S. Pat. No. 3,869,017 provides an example of an impact absorbing system for a motor vehicle containing both a plastically deformable energy absorbing frame section and break-away engine mounts which fracture in the event of a catastrophic collision and permit the engine to separate from the frame. Once the engine is separated, according to this design, the frame sections need support only the inertia load of the vehicle body. However, the design does not prevent the engine from invading the passenger compartment, where it can cause injuries to occupants.

In similar fashion, U.S. Pat. Nos. 3,718,304, 3,851,722, 4,073,357, and 4,181,192 disclose energy absorbing chassis members having severable engine mounts which allow the engine blocks to be severed from the frame in the event of a substantial impact or when a critical deceleration rate is reached. However, the releasable mounts disclosed therein do not necessarily work in cooperation with each other, so that in offset frontal impacts the engine may be only incompletely released from the frame. There is no teaching, furthermore, as to how dislocation of the engine block is controlled.

An energy absorbing motor mount assembly is disclosed in U.S. Pat. No. 4,238,104 wherein a pair of mounting elements are attached to arms that extend downward into containment housings with resilient springs for frontward and backward movement. Presumably, energy absorption is provided in fore and aft directions, but the assembly does not provide for, and in fact teaches against, the decoupling of the engine from the mounts in substantial impacts.

In view of the foregoing disadvantages, an engine block mount is needed for decoupling the inertia body of the engine from the vehicle frame while controlling its position relative to the frame during substantial impacts.

In surmounting the foregoing disadvantages, the present invention provides an engine block mount assembly comprising a set of longitudinally arranged rails having outwardly and inwardly biased springs for permitting movement of the engine during impact. The inward ends of the rails are curved downwards so that in an impact of substantial force the engine is directed inwards and toward the ground to prevent invasion of the passenger compartment by the engine block. The engine block is mounted on or to the rails by bearings which provide dampening of engine vibration and permit movement of the engine along the rails.

Unlike engine mountings of the prior art, the teaching of the present invention includes consideration of the relative positions of the engine block and automobile frame at different stages of impact: (1) when the engine moves forward (i.e., outward from the passenger compartment) while the nose of the vehicle begins to collapse; (2) when the engine meets the object into which the automobile has collided; and (3) when the engine rebounds rearward (towards the passenger compartment) after imparting its momentum into the colliding object. During each of these stages, the inertia load of the engine block is decoupled from the frame; yet the weight of the engine block is used advantageously to counter the momentum, if any, from the colliding object. As more of the frame collapses, the engine block is directed downward away from the passenger compartment by virtue of the downward path-of-least-resistance provided for the movement of the engine block. In another embodiment of the invention, pivots are used near the front of the engine block instead of bearings. However, the same purpose of directing the engine downwards on tracks using bearings located near the inward portion of the engine block is achieved, and this provides the engine with a path of less resistance than would otherwise be available if the engine block were to be fixed by conventional mounts to the automobile frame.

Consequently, the present invention provides the ability to decouple the inertia of engine mass from the frame while retaining control over the movement of the engine block. The invention provides passenger safety even in offset frontal collisions which would otherwise thwart the purposes of designs which employed releasable, shearable, or slidable mounts that do not work cooperatively with other mounts to absorb the energy of collision .

A more complete understanding of the present invention and attendant advantages and features thereof will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a diagrammatic side view of an engine block mount system of the present invention on an automobile frame;

FIG. 2a is a cross-sectional view of a rail and bearing of an engine block mount system according to the invention;

FIG. 2b is a cross-sectional view of an oval-shaped rail employed in the invention; and

FIG. 3 is a diagrammatic side view of an engine block mount system of the present invention on an automobile frame with front pivots.

FIG. 1 illustrates an exemplary embodiment of the engine block mount of the present invention. The engine block mount assembly comprises a set of rails 10 and 11 longitudinally arranged with respect to the automobile frame designated generally at 12 and 13. The front ends of the rails 10 and 11 are connected to automobile frame members 12 and 13 by means of connecting members 14 and 15, and the rear ends of the rails 10 and 11 are connected to the frame members 12 and 13 at points designated as at 16 and 17. As a variety of automobile frame shapes is possible, it is to be understood that connection of rails 10 and 11 to frame members 12 and 13, or to a unitary frame, may be accomplished by means known in the art, so long as the rearward portion of the rails are directed towards the ground to permit an engine block 18 mounted thereon to avoid the passenger compartment 34 of the vehicle.

The engine block 18 is mounted to the rails 10 and 11 by a set of bearings, designated as at 20, which permit the engine block 18 to move forward and rearward along the rails 10 and 11. A biasing means, such as springs 30, may be placed within the rails to exert a biasing force to resist the forward movement of the engine block 18 along the rails 10 and 11. Springs 32 may similarly be placed in the rearward ends of the rails 10 and 11 to exert a forward biasing force to resist the rearward movement of the engine block 18 along the rails. The biasing springs 30 and 32 are selected and adjusted to permit movement of the bearing-mounted engine block only when a certain force is reached, such as in substantial frontal collisions.

During the initial phase of a collision having substantial force of impact, the frontmost portions of the automobile frame 12 and 13 begin to collapse, and the engine block 18 moves forward along the rails 10 and 11 while being resisted by the rearward-biased springs 30. During impact between the engine block 18 and the object (not shown) into which the automobile collides, the momentum of the engine block 18 is transferred into the object to counter the momentum, if any, of the object; and thereafter the engine block moves rearward along the rails 10 and 11 against the forward-biased springs 32 and towards the ground along the downwardly-directed rear ends of the rails located near the frame at 16 and 17. Thus, once the engine block 18 has absorbed most of the frontal impact, the rails direct the absorbed energy of the impact towards the ground and away from the passenger compartment 34 located behind the firewall 35.

FIG. 2a shows an embodiment of the invention in which a bearing 31 connected by a connecting member 32 to the engine block 18 travels within a channel 33 defined by a rail shown at 10. The cross-sectional shape of the rail 10 may be any form so as to house a channel for the bearings 20, and may assume a circular or oval shape which is bent out of one piece of metal, as shown generally at 10a in FIG. 2b. The bearing 20 may be rotatably mounted on the connecting member 32, or fixed on the elongated member 32 so as to slide within the rail channel 33 as shown in FIG. 2a.

FIG. 3 shows another embodiment of the invention in which pivots 40 located on either side of the engine block 18 near the front of the engine are connected to the automobile frame portions 12 and 13 at a point relatively low to the ground. The rear of the engine block 18 has bearings 20 attached on either side of the engine block 18 and moveably attached to a pair of rails 50 which direct the engine 18 downwards upon a substantial impact which crumples the frame at portions designated generally as at 12a and 13a. The invasion of the passenger compartment 34 by the engine block 18 is thereby avoided.

Damping material such as rubber or other material may be packed between the bearings 20 and springs 30 and 32, or within the springs, so as to contribute to the ability of the engine block system to absorb engine vibration.

Although the present invention is well-suited for automobiles, it is also applicable for use in other motor vehicles such as trucks, vans, or buses. Moreover, the present invention is also applicable to rear-engine driven vehicles, since it will be understood that when such vehicles are struck from the rear, the engine block is similarly susceptible to invading the passenger compartment. In such an application, the rails will be disposed so that curved ends will direct the rear-mounted engine block forward and toward the ground in a direction away from the passenger compartment.

A variety of modifications and variations are possible in light of the above teachings without departing from the scope and spirit of the invention, which is limited only by the following claims.