Project 1

Aim : Route the wiring harness on given V-16 engine and prepare flatten view in CATIA. Apply all packaging rules and industry best practices.

Theory :

The given V-16 engine consist of following electrical components to which harness routing is required.

• 8+8 fuel injectors on the engine cylinders for both sides of the engine block (16 injectors), which are connected by a 4 pole connector with the wiring harness.
• 2 camshaft sensors on each engine block (4 camshaft sensors), which are connected by a 4 pole connector with the wiring harness. 
• Engine coolant sensor at the centre of the engine between the two blocks, which is connected by a 2 pole connector, with the wiring harness.
• Engine oil temperature and pressure sensor fitted at the oil sump of the engine on both engine cylinder blocks, which are connected by a 2 pole connector with the wiring harness. 
• 1 sensor to measure vehicle speed, which is connected by a 2 pole connector, with the wiring harness. 
• 1 sensor to sense neutral positon of the transmission assembly, which is connected by a 2 pole connector, with the wiring harness.
• An interconnection connector to connect engine harness system to vehicle harness system.

Other equipments required to complete the wiring harness routing

• Guiding channels to protect the harness routing from high heat zones of the engine wherever necessary.
• P-clamps to provide positive clamping and ensure clearance management for the routing wherever necessary.
• Sheetmetal brackets such as L-clips to mount the interconnection connector.
• Mounting clips to mount the connectors whenever required.
• Corrugated protection tubes to protect the wiring harness.

Assumpions and packing rules :

• Wiring harness routing shall provide ease in manufacturing, accessibility, easy removal and easy maintenance of attached equipments and routing harness.
• Wiring harness should be routed in such a way that it is easy to assemble on a vehicle.
• Wiring harness should be kept away from sharp environments like sheet metal brackets, panel edges, corners etc.
• Avoid harness routing and clipping in blind zone of operator during harness during installation.
• Ensure that routing meets the clearance requirements with the different surrounding parts.
• Routing shall provide enough slack for each branch to avoid additional stress on wire and terminal crimping joints but ensure that extra slack does not cause wiring harness foul with surrounding parts and impact desired clearance requirements.
• Enough clamps should be provided to ensure the positive clearance with surrounding and safety of wiring harness.
• Use of plastic guided channels are recommended to meet the clearances in critical areas if it is difficult to achieve by use of clamps.
• Branch length should be minimum 50mm.
• Minimum distance between clip and nearest branching point should be 25mm.
• Minimum distance between two breakouts  should be 50mm.
• Limit the no. of branches from single branch point to 4.
• Ensure that harness protection is provided according to surrounding temperature, manufacturabilty and expected reliability.
• The min. bend radius is to be 1.4. 
• Consider min 5% slack in the wiring harness if needed

Procedure :

Create context assembly as shown in the image above. The context assembly will contain 3D CAD data for the engine and engine harness geometrical bundle assembly. Any sheet metal component such as L-clip required will be added into the context assembly.

 Step 2. Define the connectors and components electrically

Before adding connectors into the geometrical bundle define all the required connectors or components electrically. 

To define any connector or components electrically,

a. Create required geometrical parameters like bundle connection point, connector connection axis and cavity connection axis (if required) to the connector in the part design workbench.

b. Now define connector with electrical properties such as connector connection point, bundle connection point and cavity connection point. 

c.Go to electrical part design workbench and select connector command and input the no. of terminals as per the available connector. 

d. Defining connector connection point using connector connection point command and define the parameters 

e. Define bundle connection point using bundle connection point command and define the parameters

 f. Define cavity connection point using cavity connection point command and defining the parameters

Step 3. Inserting connectors into geometrical bundle and positioning them.

a. The connectors are inserted into the geometrical bundle and positioned onto the fuel injectors, camshaft sensors, vehicle speed sensor, neutral position sensor and engine coolant sensor 

Step 4. Adding sheet metal bracket for the interconnection connector.

A sheet metal bracket (L-clip) is added inside the context assembly to mount the interconnection connector. The L-clip is added inside the context assembly and not into the geometrical bundle since it will not be bought along with the wiring harness. Existing bolt on the engine is used to mount the sheet metal bracket. The bracket should be provided with a suitable locking feature in clockwise direction. The ribs on the current engine design can be taken into advantage for the locking purpose so that it cant rotate freely. The design idea should be discussed with engine design team while using the existing bolts and screws so that there wont be any disturbance for the normal functioning of the engine as well.

Step 5. Defining mounting clip electrically so that the interconnection connector can be mounted on the sheet metal bracket

To define mounting clip electrically

a. First define the geometrical parameters which is cavity connection axis in the part design workbench 

Step 6. Mounting the interconnection connector on the sheetmetal bracket

To mount the interconnection connector onto the sheet metal bracket, first the mounting clip is mounted on the sheet metal bracket

Step 7. Adding P-clamps to provide positive clamping for the wiring harness.

a. P-clamps should be defined with electrical properties before inserting into the geometrical bundle assembly.

First define geometrical parameters such as entry point, entry plane, exit point, exit plane and base plane 

Step 8. Adding plastic guiding channels 

The given V-16 engine has 8 injectors both on the left and right side of the engine which are close to one another, hence using plastic guiding channels is the best option for easy and proper routing of the wiring harness and maintain clearance requirement of the wires from the high temperature parts of the engines. 

Before adding guiding channels into the geometrical bundle assembly it is necessary to define electrical properties to it, which is done by following steps.

a. First create geometrical parameters such as bundle entry points, and external reference line in the part design workbench to route the wiring harness into the guiding channel

b. Go to electrical part design and define the part as equipment using equipment command and define bundle connection points using bundle connection point command towards the entry points of the guiding channel

Step 9. Routing the wiring harness to the connectors 

Go to electrical harness assembly workbench and select geometrical bundle command and select the geometrical bundle in the model tree. Then select the multibranchable command to start the bundle routing and go to route definition.

i) The bundle routing starts from interconnection connector and then to the P-clamps and to the guiding channels. 

ii) Addding branching points wherever necessary using add branch point command

iii) Adding branches wherever necessary to connect the various connectors to the main branch as shown below using add branches  command and routing definition into it.

iv) To route the wiring harness through the guiding channels select external curve and click on the line in the guiding channel.

v) Add branching points to the wiring bundle and add branches to to connect the wiring to the connectors at the injectors 

Thus the routing is completed as shown below.

CATLOUGE

ENGINE WITH ROUTING

i) To add protective coverings on the wiring harness, first create a protective covering by using define protection part command in the electrical part design workbench. Select any plane, and define the parameters as per the requirement.

ii) A corrugated tube is created.

ROUTING

Step 12. To create flatten view of the engine harness 

i) Create a new product file and save it in the same folder where the wiring harness is saved.

ii) Go to Electrical harness flattening workbench and select harness flattening parameters and define harness flattening parameters into it

iii) To import the harness file into the harness flatten file, select extract command and go to harness assembly window and click on the geometrical bundle. The harness routing is added into the harness flatten

iv) Go to flatten command and select the appropriate face and select all the branches of the wiring harness, the harness is flattened

v) Use rotate command to rotate the branches and make the wiring harness routing presentable in the drawing sheet. Following which the connectors and other devices are also to be manipulated in the assembly design workbench to give a proper view while drafting on the drawing sheet.

FLATTRING

v) The flattening view is ready and can be used for drafting.

vi) Go to assembly design workbench, and select view from reference command and select the plane to add plane for the annotation, select flag note with leader and add annotations

Step 13. Create drawing of the flattened harness

i) Go to new and select drawing to create a new drawing file.

ii) Select front view command, go to the flattened harness window and select a suitable face to create drafting of the harness. The wiring harness appears

DRAWING 

Conclusion: Thus the engine harness routing is completed and the flatten view drawing is created.