Abstract:
An engine component ( 2, 3 ) is disposed in front of or behind the vehicle engine with respect to the direction of vehicle travel. The component ( 2, 3 ) is covered by a protective shell ( 10 ) from an opposite direction from the engine ( 1 ). The protective shell ( 10 ) is fixed to the engine ( 1 ) by brackets ( 5, 6 ). Stoppers ( 11 - 13 ) in the protective shell ( 10 ) limit the displacement of the protective shell ( 10 ) towards the engine ( 1 ) from exceeding a predetermined distance. The brackets ( 5, 6 ) are provided with deformable members ( 5, 6 A) which deform in response to an impact load applied to the protective shell ( 10 ) and guide the protective shell ( 10 ) only in a direction towards the engine ( 1 ) up to the position which is limited by the stoppers. In this manner, the protective properties of the external components ( 2, 3 ) with respect to an impact load is enhanced.

Description:
FIELD OF THE INVENTION 
     This invention relates to the protection of externally-fitted components (hereafter “external components”) of an internal combustion engine for a vehicle. 
     BACKGROUND OF THE INVENTION 
     Tokkai Hei 11-210488 published by the Japan Patent Office discloses a protective device for protecting external components of an internal combustion engine for a vehicle from suffering damage during a vehicle collision. 
     According to this prior art, an internal combustion engine is disposed along the longitudinal center plane in the front section of a vehicle. In other words, the engine is disposed so that the crank shaft is substantially parallel to the vehicle axle. An external component such as a fuel pump is fitted to the front face of the internal combustion engine. One end of a high-temperature pipe for cooling water is connected to the engine. The cooling water pipe is highly rigid and circulates cooling water from the engine to a radiator which is positioned in front of the engine. The other end of the high-temperature cooling water pipe is connected to the radiator after crossing the front face of the fuel pump so that the fuel pump is protected. 
     A muffler cover covering the fuel pump is respectively fixed to a cylinder head cover covering the cylinder head of the engine  1  and the high-temperature cooling water pump. The muffler cover muffles noise from the pump. Furthermore when the vehicle experiences a collision, the muffler cover reduces the impact load applied to the fuel pump. 
     SUMMARY OF THE INVENTION 
     To summarize the above, the prior art uses a high-temperature cooling water pipe and a muffler cover as a protector for the fuel pump. However the pattern in which the cooling water pipe and the muffler cover deform and displace varies with respect to the initial position and size of an impact load when the vehicle experiences a collision. Consequently there is the possibility that the fuel pump will unexpectedly be damaged as a result of deformation or displacement of the protector. 
     It is therefore an object of this invention to improve reliability of the protector with respect to an impact load by limiting the preferred direction of deformation or displacement of a protector resulting from an impact load. 
     In order to achieve the above object, this invention provides a protective device protecting an engine component disposed in front of or behind the vehicle engine with respect to a direction of vehicle motion. The device comprises a protective shell covering the engine component from an opposite direction from the engine, keeping more than a predetermined distance from the engine component, a stopper limiting displacement of the protective shell towards the engine from exceeding the predetermined distance, and a deformable member deforming in response to an impact load applied to the protective shell and guiding displacement of the protective shell towards the engine up to a position limited by the stoppers. 
     The details as well as other features and advantages of this invention are set forth in the remainder of the specification and are shown in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of the essential parts of an internal combustion engine fitted with a protective device according to this invention. 
         FIG. 2  is an exploded transverse view of the protective device and fuel injection device protected thereby. 
         FIG. 3  is a plan view of the protective device. 
         FIG. 4  is a front view of the protective device. 
         FIG. 5  is a plan view seen from below of the protective device. 
         FIG. 6  is a side view of the protective device. 
         FIG. 7  is a front view of the protective device mounted on the engine. 
         FIG. 8  is a plan view seen from below of the protective device mounted on the engine. 
         FIGS. 9A and 9B  are a schematic cross-sectional view and a schematic horizontal sectional view of the fuel injection device and the protective device mounted on the engine. 
         FIGS. 10A and 10B  are similar to  FIGS. 9A and 9B  but show the behavior of the protective device resulting from a relatively small vehicle collision. 
         FIGS. 11A and 11B  are a front view and a plan view seen from below of the protector showing the path of deformation and displacement of the protective device resulting from a full-lapped collision. 
         FIGS. 12A and 12B  are similar to  FIGS. 11A and 11B  but show the path of deformation and displacement of the protective device resulting from an offset collision. 
         FIGS. 13A and 13B  are a schematic cross-sectional view and a schematic horizontal sectional view of the fuel injector and the protective device mounted on the engine in order to show the protection structure of the protecting device associated with the engine when the protective device can not by itself absorb the load resulting from a collision. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1  of the drawings, a four-cylinder internal combustion engine  1  for a vehicle is a transverse-mounted engine. In other words, the engine  1  is disposed so that the crank shaft is substantially parallel to the vehicle axle. 
     A fuel supply device is disposed on the front face of the engine  1 . The fuel supply device is a so-called common rail fuel supply device and comprises four fuel injectors  2  injecting fuel in a sequential manner in each cylinder. The fuel is supplied under a constant pressure from a fuel supply pipe  3  comprising the common rail. The protective device for external components according to this invention has the object of protecting the fuel supply device as an example of an external engine component. The downward direction of  FIG. 1  corresponds to the direction in which the vehicle normally runs. 
     Referring now to  FIG. 2 , the protective device comprises a protector  4 , a pair of brackets  5  and a pair of brackets  6 . 
     The protector  4  covers the four fuel injectors  2  and the fuel supply pipe  3  distributing fuel to the fuel injectors  2 . The upper end and lower end of the protector  4  are fixed to the engine  1  respectively through the brackets  5  and brackets  6 . 
     Referring to  FIGS. 3-6 , the protector  4  comprises a protective shell  10 , a pair of upper stoppers  11 , a pair of sub-stoppers  13  and a lower stopper  12  which are integrally formed of a highly rigid material. 
     The protective shell  10  has a cross-section in the shape of the letter “U” and has an opening facing the engine  1 . The pair of upper stoppers  11  projects from the upper end of the protective shell  10  towards the engine  1 . The pair of sub-stoppers  13  project from the lower end of the protective shell  10  towards the engine  1 . The lower stoppers  12  project from between the two sub-stoppers  13  on the lower end of the protective shell  10  towards the engine  1 . The lower stopper  12  has a substantially trapezoidal planar shape, the width of which narrows towards the engine  1 . A hole  12 B is formed in the center of the stopper  12  in order to reduce the weight of the component. The periphery of the hole  12 B is strengthened by ribs  12 A. 
     Each of the brackets  5  comprises a flat plate and is spot-welded to the upper stopper  11 . A bolt hole  5 A and a fitting hole  5 B for a harness are formed on the bracket  5 . The bracket  5  is fixed to the engine by a bolt  8  fitted into the bolt hole  5 A. The members comprising the bracket  5  have predetermined dimensions and quality in order to be less rigid than the protector  4 . The bracket  5  therefore deforms when a large load is applied by the upper stopper  11 . Since the bracket  5  comprises a flat plate, deformation is limited to a fixed pattern such that the bracket  5  is folded at a transverse line crossing the flat plate at a right angle. The bracket  5  refers to the component defined as the “second bracket” in the claims. 
     A part of the sub-stopper  13  forms a stay  14  which is bent approximately 90 degrees in a downward direction. The tip of the stay  14  is bent approximately 90 degrees outwardly in order to be parallel to the wall face of the main section of the engine  1 . The section bent outwardly is referred to as the bending section  15 . 
     As shown in  FIGS. 9A and 9B , the bracket  6  is a member which supports the fuel supply pipe  3 . As shown in  FIG. 2 , the bracket  6  comprises a bolt hole  6 C on a face parallel to the wall face of the main section of the engine  1 . Referring again to  FIGS. 9A and 9B , the bracket  6  is fixed to the projection which protrudes from the wall face of the main section of the engine  1  by a bolt  18 A which is fitted into the bolt hole  6 C. A tab  6 A is formed on the bracket  6  in proximity to the bolt hole  6 C. The tab  6 A protrudes inwardly, in other words, towards the lower stopper  12 . 
     The sub-stopper  13  is fixed to the bracket  6  in the following manner. The bending section  15  of the sub-stopper  13  overlaps with the tab  6 A. A bolt  18 B is fitted through the bolt hole  15 A formed on the bending section  15  and the bolt hole  6 B formed on the tab  6 A and is fixed by a nut. The tab  6 A and the bending section  15  are manufactured to have a rigidity which is lower than the rigidity of the bracket  6  and the protector  4 . The tab  6 A comprises a section of the bracket  6  and the bending section  15  comprises a section of the sub-stopper  13 . However as shown in  FIG. 4 , the tab  6 A protrudes from the bracket  6  and the bending section  15  protrudes from the stay  4 . 
     Thus a variation in the vertical width of the tab  6 A and bending section  15  as shown in the figures allows the rigidity of those components to be set to an arbitrary degree while the same material as the bracket  6  or the stay  14  is used. Thus the rigidity of the tab  6 A or the bending section  15  can be set to be lower than the bracket  5 . 
     The bracket  6  corresponds to the “first bracket” in the claims. The bracket  5  and the tab  6 A/bending section  15  correspond to the “deformable members” in the claims. More precisely, the bracket  5  comprises the upper deformable member and the tab  6 A/bending section  15  comprises the lower deformable member. 
     The protective shell  10  is formed with a predetermined length with respect to the transverse section of the vehicle in order to cover the fuel supply pipe  3 . A predetermined gap is formed between the protective shell  10  and the fuel supply pipe  3 . A plurality of heat release holes  10 A are provided in the protective shell  10  in order to assist in radiating heat from the fuel supply pipe  3  so that the fuel supplied to the fuel injector  2  from the fuel supply pipe  3  does not overheat. The holes  10 A are formed at a position which does not adversely affect the rigidity of the protective shell  10 . The heat release holes  10 A promote heat radiation from the fuel supply pipe  3  and also have the function of reducing the weight of the protective shell  10 . 
     The tip of the stopper  12  differs from the tip of the other stoppers  11  and  13  in that it is not fixed to the engine  1  and is positioned near to the wall face of the main section of the engine  1  as a free end. 
     The upper stopper  11  is fixed to the engine  1  using the bracket  5 . The dimensions of the upper stopper  11  are preset so that the distance from the tip to the wall face of the main section of the engine  1  is smaller than the predetermined gap referred to above. The dimensions of the lower stopper  12  are preset so that the distance from the tip of the lower stopper  12  to the wall face of the main section of the engine  1  is smaller than the predetermined gap. The position at which the lower stopper  12  is formed is the initial point of application of a load during a full-lapped collision. 
     A full-lapped collision is a vehicle collision with an object which strikes essentially the longitudinal center-plane of the object for protection. An offset collision is a vehicle collision with an object which strikes essentially to one side of the longitudinal center-plane of the object for protection. 
     The object for protection in this embodiment is a fuel supply pipe  3  and a fuel injector  2 . The longitudinal center-plane of the object for protection is positioned between the two inner fuel injectors  2  of the four fuel injectors  2 . The lower stopper  12  is formed in this position. 
     Referring to  FIGS. 7 and 8 , the protective shell  10  of the protector  4  fixed to the engine  1  in the manner described above is positioned in front of the fuel supply pipe  3  and the fuel injector  2  and covers those two components completely. 
     In a protective device as constituted above, when the vehicle collides with an object and a impact load is applied to the protector  4 , firstly the bracket  5  and the tab  6 A deform and the protective shell  10  displaces in a direction towards the engine  1 . This displacement is stopped as the upper stopper  11  and the lower stopper  12  abut with the wall face of the main section of the engine  1 . The setting of the dimensions as described above means that when the abutment occurs, the protective shell  10  does not come into contact with the fuel supply pipe  3  or the fuel injectors  2 . Further load is resisted by the whole of the high-rigidity protector  4  including the upper stopper  11  and the lower stopper  12  which have abutted with the wall face of the main section of the engine  1 . Consequently the fuel supply pipe  3  and the fuel injectors  2  are protected. 
     Next referring to  FIGS. 9A ,  9 B,  FIGS. 10A ,  10 B,  FIGS. 11A ,  11 B,  FIGS. 12A ,  12 B and  FIGS. 13A ,  13 B, the protection mechanism of the protective device will be described with respect to various collision scenarios. 
     These figures are schematic figures describing the deformation and displacement of members and the point of application of load resulting from a vehicle collision. For the purposes of description, the members have been depicted in either a simplified or an exaggerated form. Thus the dimensions or shape of the members shown in the figures do not always correspond with the other figures. 
     Referring to  FIGS. 9A-9C , the fixing of the protector  4  on the engine  1  is enabled by fixing each of the pair of the upper stoppers  11  using a bolt  8  through the bracket  5  to an upper section of the main section of the engine  1 . Furthermore each of the pair of the brackets  6  is fixed using the bolt  18 A to a lower part of the main section of the engine  1 . The tab  6 A of the bracket  6  and the bending section  15  of the stay  14  on the tip of the sub-stopper  13  are fixed using the bolt  18 B. The respective tips of the upper stoppers  11  and the lower stopper  12  protrude toward the main section of the engine  1 . The interval between the respective projecting ends and the wall face of the main section of the engine  1  is smaller than the interval between the fuel supply pipe  3  and the protective shell  10 . The bending section  15  of the stay  14  on the tip of the stopper  13  and the tab  6 A of the bracket  6  overlap and are approximately parallel to the wall face of the main section of the engine  1 . 
     As shown in  FIG. 9B , the positional relationship of the protective device and the fuel injectors  2  is arranged so that two of the injectors  2  are disposed between the stays  14  of the two sub-stoppers  13  and the lower stopper  12 . Each of the other two fuel injectors  2  is disposed on the outer side of each stay  14 . The two arrows in the figure show the initial position of the impact load when the vehicle undergoes a full-lap collision or an offset collision. 
       FIGS. 10A and 10B  describe the displacement and deformation occurring in a full-lap or an offset collision when a relatively small impact load is applied to the protector  4 . 
     As shown by one of the arrows in  FIG. 11A , when a full-lap load is applied to the protective shell  10  of the protector  4 , the load as shown by  FIG. 9B  firstly bends each of the tabs  6 A of the brackets  6  through the bending sections  15  of the sub-stoppers  13 . In contrast, each of the bending sections  15  is bent into an acute angle on the border with the stay  14 . Since the rigidity of the tab  6 A and bending section  15  comprising the lower deformable member is set to be lower than the bracket  5  which comprises the upper deformable member, the tab  6 A and the bending section  15  undergo a large deformation in advance of other components as a result of the impact load. 
     As a result, the sub-stoppers  13  approach the engine  1 . The protective shell  10  rotates downwardly about the connection point of the engine  1  with the bracket  5  as shown by the broken arrow in 
       FIG. 10A . Accordingly, the bracket  5  is bent downward. The impact load is thus absorbed by the deformation of the tab  6 A and bending section  15  as well as the displacement of the protective shell  10 . When a larger collision occurs, the stopper  12  abuts with the wall face of the main section of the engine  1  to prevent the protective shell  10  from further approaching the engine  1 . In summary, for relatively small impact loads, the protective device absorbs the collision mainly as a result of the deformation of the bending section  15  and the tab  6 A comprising the lower deformable member. 
     At this time, the displacement of the protector  4  shows the direction in which the engine  1  is approached as a result of the pair of tabs  6 A and bending sections  15  respectively bending at the ends. In this state, the gap between the protective shell  10  and fuel supply pipe  3  is maintained. Consequently the impact load does not reach the fuel supply pipe  3 . The protector  4  can only displace towards the engine  1  since the tab  6 A and the bending section  15  deform in a predetermined pattern. As a result, the impact load has no effect on the fuel injectors  2  disposed between the pairs of stays  14  and lower stoppers  12  since the protector  4  does not displace or deform in a transverse direction. 
       FIGS. 11A ,  11 B and  FIGS. 12A ,  12 B show the difference in the behavior of the protector  4  during a full-lapped collision and an offset collision. 
       FIGS. 11A and 11B  show a full-lapped collision. During a full-lapped collision, as described above, the whole protector  4  undergoes displacement describing a downward slope as shown in  FIG. 9A . However the pair of tabs  6 A and the bending section  15  deforms uniformly as shown in  FIG. 11B  as seen from above and the protector  4  remains parallel to the engine  1 . 
       FIGS. 12A and 12B  show an offset collision. During an offset collision, the tab  6 B and the bending section  15  which are near to the point of application of an impact load undergo a greater flexural deformation than the other tab  6 B and bending section  15 . As a result, sections of the protector  4  which are near to the point of application of the impact load approach the engine  1 . However since the respective ends of the tab  6 A and the bending section  15  are bent, the protector  4  can only displace towards the engine  1 . 
     Although the protector  4  and the engine  1  are not parallel to one another, the protector  4  does not displace to the right or the left in  FIG. 12B . Thus even during an offset collision, the protective shell does not come into contact with the fuel supply pipe  3  and the stay  14  and the lower stopper  12  do not interfere with the fuel injectors  2 . 
     Next referring to  FIGS. 13A and 13B , the deformation and displacement of members will be described when a larger impact load than that described in  FIGS. 10A and 10B  is applied to the protector  4 . 
     When an impact load is not absorbed by the displacement and deformation of the members shown in  FIGS. 10A and 10B , a further thrust towards the engine  1  is applied to the protector  4 . Under these conditions, the further thrust is concentrated on the bracket  5  comprising the upper deformable member and a flexural deformation results in the bracket  5  as shown in  FIG. 13A . This is due to the fact that the lower stopper  12  has already abutted with the wall face of the main section of the engine  1 . As a result, the protector  4  absorbs the impact load by displacing obliquely upward toward the engine  1  or rotating in a counterclockwise direction in  FIG. 13A . 
     As described above, the distance between the tips of the upper stopper  11  and lower stopper  12  and the wall face of the main body of the engine  1  is smaller than the predetermined gap set between the protective shell  10  and the fuel supply pipe  3 . Thus even when the tips of the stoppers  11  and  12  as shown in  FIGS. 13A and 13B  respectively abut with the wall face of the main section of the engine  1 , the protective shell  10  does not come into contact with the fuel supply pipe  3 . 
     Thereafter the tips of the upper and lower stoppers  11  and  12  of the protector  4  abut with the wall face of the main body of the engine  1 . Consequently the high rigidity of the protector  4  resulting from the integration with the engine  1  resists the impact load and prevents damage to the fuel supply pipe  3  and the fuel injectors  2 . 
     As described above, the protective device according to this invention absorbs impact loads firstly as a result of deformation of the deformable members provided on the upper and lower sections of the protective shell  10  irrespective of whether the collision is a full-lapped collision or an offset collision. Load not absorbed at that stage is supported by the high rigidity of the protector  4 . The two-stage protective structure described above effectively prevents damage to the fuel supply pipe  3  or the fuel injectors  2 . 
     The structure and dimensions of the deformable members accurately regulate the direction and dimension of the displacement of the protector  4  resulting from an impact load. Irrespective of whether the collision is a full-lapped collision or an offset collision, there is no possibility of interference by the protector  4  with the fuel supply pipe  3  or the fuel injectors  2 , since the protector  4  does not undergo deformation or displacement in an unexpected direction. Thus the layout of engine components such as the fuel supply pipe  3  or the fuel injectors  2  is simplified since the deformable members accurately defines the path of the motion by the protector  4 . 
     This protective device fixes the protective shell  10  to the engine  1  using a pair of brackets  6 . The connecting section of the bracket  6  and the protector  4  and the connecting section of the bracket  6  and the engine  1  are offset from each other in the transverse direction of the vehicle. Thus the connecting section of the bracket  6  and the protector  4  deform in response to an impact load and have the function of guiding the protective shell  10  only in a direction towards the engine  1 . This guiding function greatly contributes to the accurate regulation of the path of the motion of the protective shell  10 . 
     Furthermore the bracket  5  comprising flat plate and forming the upper deformable member only deforms in a direction in which the plate bends under a load. The bracket  5  therefore also has the function of guiding the protective shell  10  only in a direction of approaching the engine  1 . Consequently the protector  4  deforms in a preset fixed pattern irrespective of the point of application of the load and therefore interference with the fuel supply pipe  3  or the fuel injectors  2  can be avoided. 
     In this protective device, the amount of energy of the collision which can be absorbed can be arbitrarily set by setting the rigidity of the deformable members. 
     Furthermore since the rigidity of the lower deformable member is set to be lower than the rigidity of the upper deformable member in this protective device, the energy of the collision can be absorbed by deformation firstly of the lower deformable member. In the event that energy remains unabsorbed, the remaining energy of the collision can subsequently absorbed by the deformation of the upper deformable member. 
     Thereafter the protective structure becomes highly rigid due to integration with the engine  1  resulting from the abutment of the stoppers  11  and  12  with the engine  1 . Therefore it is possible to ensure protection of the fuel supply pipe  3  and the fuel injectors  2  with this type of multi-layered energy absorbing structure. 
     In this protective structure, the bracket  5  forming the upper deformable member supports the protective shell  10  using the upper stopper  11 . The tab  6 A and the bending member  15  forming the lower deformable member support the protective shell  10  using the sub-stopper  13 . Although these deformable members can directly support the protective shell  10 , it is possible to decrease the longitudinal dimensions of the bracket  5  or the bracket  6  which comprises the tab  6 A through the upper stopper  11  or the sub-stopper  13 . This structure enables the space occupied by the deformable members to be reduced while reducing the possibility that the deformable members will interfere with the objects to be protected. 
     The contents of Tokugan 2004-199246, with a filing date of Jul. 6, 2004 in Japan, are hereby incorporated by reference. 
     Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiments described above. Modifications and variations of the embodiments described above will occur to those skilled in the art, within the scope of the claims. 
     For example, In the above embodiment, although the tab  6 A is formed on the bracket  6  supporting the fuel supply pipe  8  on the engine  1 , it is possible to support the tab  6 A on the engine  1  using a separate independent bracket. 
     In the above embodiment, although the fuel supply pipe  3  and the fuel injectors  2  comprise the object for protection, this invention may be applied for the protection of any other engine components disposed outside the engine main body. 
     In the above embodiment, the upper stopper  11  is disposed at two positions on the upper section of the protective shell  10 . The lower stopper  12  is provided at one position on the lower section of the protective shell  10 . However the disposition of the stoppers  11 - 13  can be arbitrarily varied in response to the shape and disposition of the external component which is to be protected. This includes disposing the upper stopper  11  at three or more positions on the upper section of the protective shell  10  or disposing the lower stopper  12  at a plurality of positions on the lower section of the protective shell  10 . It should be noted that this invention can be realized with at least one single stopper and one single deformable member. 
     In the above embodiment, although the stoppers  11 - 13  is integrated with the protective shell  10 , one or more of the stoppers  11 - 13  may be formed by a member which is separate from the protective shell  10  and can be fixed to the protective shell  10 . 
     In the above embodiment, the engine component to be protected is positioned in front of the engine  1 . However even when the engine component to be protected is behind the engine  1 , the protective device can display the same preferred effect with respect to a collision by reversing the longitudinal positions. 
     In the above embodiment, the upper and lower deformable members are used to adsorb the impact load due to vehicle collision, but the protector provided with only the upper or lower deformable member will bring a considerable effect on the protection of the engine component.