WIRING HARNESS ROUTING AROUND A ENGINE

ROUTING WIRING HARNESS IN AN ENGINE

The wiring harness is the combination of electrical cables, or assembly of wires, that connects all electrical and electronic (E/E) components in the automotive vehicle, like sensors, electronic control units, batteries, and actuators.

Considerations

• The wiring harness around the engine is routed keeping these considerations in mind:
• The distance from the exhaust from the wiring harness should be a minimum of 50mm.
• Distance between two clamps on a straight branch should be mot more than 200mm.
• The minimum branch length should be 50mm.
• The distance between a clip and the nearest branching point should be a minimum of 25mm.
• The distance between two straight connection points should be a minimum of 200mm.
• The bend radius ratio should be 1.4 times the bundle radius.
• All the bundles should be fully connected.

Design Methodology

The Design Process is done in   steps:

Step 1: Downloading and defining the wiring harness components as electrical equipment.

An interconnection connector with 12 pins is used for initiating the routing of the engine wiring harness. A 4 pin connector connects to the engine cylinder heads mounted at each valve of the engine. For the sensors, a 2 pin connector is used.

The geometrical properties of the connectors is first defined: The bundle connection point and the connector connection point along with the connector connection axis. The component is then defined electrically: Connectors are defined with the connector connection and bundle connection properties. The clips and clamps are also defined as electrical parts. Lastly the geometrical properties of the channel are defined with the lower channel. The channel is also defined as an electrical component and the bundle connection points for the channel are defined.

(Defining electrical properties)

Step 2: Setting up the engine and wiring harness assembly:

The engine assembly file is converted into skin data which is used to mount the wiring harness components. This is done to save computation time and memory. A product file is created as the wiring harness context assembly and the engine background skin data is saved in the same product.

Another product file for wiring harness bundle assembly is created, the wiring harness components will be stored in this assembly: The clips and clamps, connectors, channels and the multi branch-able will be a part of this assembly. The L clip and all the other component that are used to just mount the harness components (which are without electrical properties) will be a part of wiring harness context assembly and not a part of bundle assembly.

(Routing connectors)

Step 3: Manipulating the connectors and mounting electrical equipments to appropriate positions:

The connectors are added to the wiring harness bundle assembly and moved and rotated to their appropriate connection positions. Recurring connectors are copied and pasted and translated to their respective positions. The positions need not be absolute as this will just be an initial design concept.

The 4 pin connectors are connected with the engine valve connectors. The 2 pin connector from the sensors. The interconnector connector is mounted on the flange through which all the branches of the engine harness bundle originate. The Interconnector connector is mounted on the clip electrically and the assembly is mounted on the L-clip.

(Connectors at position)

Step 4: Adding Fir tree clips from routing the harness bundles.

The fir tree clips are added to the wiring harness bundle assembly. The design rules, considerations and best practice are followed to ensure the best routing of the wiring harness.

Step 5: Routing the multi branch-able harness:

The Multi branch-able is originated from the interconnection connector and through the fir clips, the bundles are routed to the different connectors. Proper bundle diameter is ensured and the bend radius is kept a minimum of 1.4 times the bundle diameter. All the connectors are connected using multiple branching points emerging off the main branch. Slacks are applied in the bundles to route the bundles properly.

(Routing Wiring harness)

(Adding sub branches)

Step 6: Checking the Electrical continuity of the bundle:

The electrical continuity of the bundles is then checked using the Search command in CATIA; Search> Advance> Electrical WB, Bundle Segment type, fully continuous; Check for both true and false. For True, all branches should be shown and for false, no branches should be shown.

(Full Wiring Harness)

(Checking Connectivity of wiring harness)

(Checking Connectivity of wiring harness)

 

Step 7: Wiring Harness Flattening:

The wiring harness is then flattened using the Electrical Harness Flattening WB. Create a new product file for the flattening in the flattening workbench and define the Harness Flattening Parameters, save it in the same folder with all other files of engine harness project and then extract the geometric bundle from the wiring harness context product file. Then using the flatten command flatten the harness by selecting all branches to flatten. Manipulate the flat harness as required for the drawing and save. Open a drawing file and create a 2D representation of the wiring harness.

(Flattening Parameters)

(Flattened Drawing)

This concludes the design of the wiring harness for the Engine.