Project 1
Aim: Route the wiring harness on the given-16 engine and prepare to flatten the view in CATIA. Apply all packaging rules and industry best practices.
The given-16 engine consists of the 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 4pole connector with the wiring harness.
- 2 camshaft sensors on each engine block(4camshaft 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 2pole 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 2pole 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 the neutral position of the transmission assembly, which is connected by a 2 pole connector, with the wiring harness.
- An interconnection connector to connect the engine harness system to the vehicle harness system.
Other equipment 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 asL-clips to mount the interconnection connector.
- Mounting clips to mount the connectors whenever required.
- Corrugated protection tubes to protect the wiring harness.
Step 1 Context Assembly
Wiring harness routing shall provide ease in manufacturing, accessibility, easy removal and easy maintenance of attached equipment and routing harness. The wiring harness should be routed in such a way that it is easy to assemble on a vehicle.
The wiring harness should be kept away from sharp environments like sheet metal brackets, panel edges, corners etc. Avoid harness routing and clipping in the blind zone of the operator during harness 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 because wiring harness foul with surrounding parts and impact desired clearance requirements.
Enough clamps should be provided to ensure positive clearance with the surroundings and the safety of the wiring harness. The use of plastic guided channels is recommended to meet the clearances in critical areas if it is difficult to achieve by the use of clamps.
The branch length should be a minimum of 50mm.
The minimum distance between the clip and the nearest branching point should be 25mm.
The minimum distance between two breakouts should be 50mm.
Limit the no. of branches from a single branch point to 4.
Ensure that harness protection is provided according to surrounding temperature, manufacturability and expected reliability.
The min. bend radius is to be 1.4.
Consider min 5% slack in the wiring harness if needed.
Create context assembly 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 electrically
Before adding connectors into the geometrical bundle define all the required connectors electrically.
To define any connector electrically,
- 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 as shown in the image below.
- Now define connector with electrical properties such as connector connection point, bundle connection point and cavity connection point. Go to the electrical part design workbench and select connector command and input the no. of terminals as per the
Available connector.
- Defining connector connection point using connector connection point command and defining the parameters
- Define bundle connection point using bundle connection point command and define the parameters
- Define cavity connection paint using the cavity connection point command and define the parameters. Hence the connector is defined electrically.
Step 3. Inserting connectors into the geometrical bundles and positioning them.
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
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. The existing bolt on the engine is used to mount the sheet metal bracket.
The bracket should be provided with a suitable locking feature in a clockwise direction. The ribs on the current engine design can be taken as an advantage for the locking purpose so that they can’t rotate freely. The design idea should be discussed with the engine design team while using the existing bolts and screws so that there won’t be any disturbance to 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
- First, define the geometrical parameters which are the cavity connection axis in the part design workbench
- Defining electrical properties of the mounting clip by going to the electrical part design workbench.
- Define the clip as mounting equipment using the mounting equipment command.
- Select cavity command and define the parameters
Step 6. Mounting the interconnection connector on the sheet metal bracket
- To mount the interconnection connector onto the sheet metal bracket, first, the mounting clip is mounted on the sheet metal bracket.
- Then the interconnection connector is electrically connected with the mounting clip by using connect electrical devices command in the electrical assembly design workbench.
Step 7. Adding P-clamps to provide positive clamping for the wiring harness.
- 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
- Go to the electrical part design workbench and define the P-clamps as support using the support command and define the parameters
- Use the support command again and select the first plane definition as an exit point and exit plane, this is done to obtain wiring entry from either side of P-clamps.
- P-Clamps are mounted on the existing bolts and screws to provide positive clamping and ensure proper clearance management for the wiring harness routing.
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 maintaining the 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 its electrical properties to it, which is done by following steps.
- First, create geometrical parameters such as bundle entry points, and external reference lines in the part design workbench to route the wiring harness into the guiding channel
- Go to electrical part design and define the part as equipment using equipment command and define the bundle connection points using bundle connection point command towards the entry points of the guiding channel now insert the guiding channel into the geometrical bundle and position it accordingly as required, both on the left and right side of the engine discuss with the engine design team to provide additional tapping wherever required to mount the guiding channels with bolts and screws.
Now as all the components are inserted and positioned into the geometrical bundle, the assembly is ready to route the harness.
Step 9. Routing the wiring harness to the connectors
Go to the electrical harness assembly workbench and select the 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.
- The bundle routing starts from the interconnection connector and then to the P-clamps and the guiding channels.
- Adding branching points wherever necessary using add branch point command
- Adding branches wherever necessary to connect the various connectors to the main branch using add branches command and routing definition into it.
- To route the wiring harness through the guiding channels select the external curve and click on the line in the guiding channel.
- Add branching points to the wiring bundle and add branches to connect the wiring to the connectors at the injectors
- To add protective coverings on the wiring harness, first create a protective covering by using the define protection part command in the electrical part design workbench. Select any plane, and define the parameters as per the requirement.
- Go to new and select catalogue document, select add family command and define the type as conduit save the file to create a catalogue for protection tube.
- A catalogue file is created
- Save the file to create a catalogue for the protection tube.
- The created corrugated tube can be added to the catalogue by the store device command and by selecting the catalogue file created for the protection tube which can be used to add protection to the harness as and when required.
- To add a protection tube to the wiring harness, select the light protective coverings command and select the required size protection tube from the catalogue.
Step 11. Check bundle connectivity
To check bundle connectivity go to edit, select search option, go to the advanced tab and select the workbench as electrical, type as bundle segment and attribute as fully connected and attribute criterion as true if, you want to check all connected bundle segments and false if you want to check all the unconnected bundle segments.
Now as the branches are fully connected we can proceed further with harness flattening.
Step 12. To create a flattened view of the engine harness
- Create a new product file and save it in the same folder where the wiring harness is saved.
- Go to Electrical harness flattening workbench and select harness flattening parameters and define harness flattening parameters into it
- To import the harness file into the harness flatten the file, select the extract command and go to the harness assembly window and click on the geometrical bundle. The harness routing is added into the harness flatten
- Go to flatten command and select the appropriate face and select all the branches of the wiring harness, the harness is flattened
- Use rotate command to rotate the branches and make the wiring harness routing presentable in the drawing sheet. Following this, 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.
- The flattening view is ready and can be used for drafting.
Step 13. Create a drawing of the flattened harness
- Go to new and select drawing to create a new drawing file.
- Select the front view command, go to the flattened harness window and select a suitable face to create drafting of the harness. The wiring harness appears as shown below.
- To make the bundle segments visible right-click on the drawing sheet and go to properties, in the view tab, highlight the 3D wireframe which is always visible in the dress-up settings.
