Project 1

WIRING HARNESS DESIGN 

AIM

Design and develop the Wiring harness on Given V6 Engine and Prepare flatten view drawing in CATIA V5. Application of all Packaging rules, Industry best practices studied in this course shall be demonstrated in design.

INTRODUCTION

• A wire harness, also commonly referred to as a wiring harness, is an exterior sheath used to cover some types of electronic wires. Generally,
• wiring harnesses are made of thermoplastic or thermoset materials that can help protect the cables from the environment.

Engine Harness

• An engine wiring harness is constricted wires, cables, terminals, and connectors controlling a vehicle’s electrical system.
• It relays electrical power and control information to components such as batteries, alternators, fuel injectors, fuses, audio systems, blower motors, fuel injectors, and computers.
• Wire harness companies customize it for every location, application, and design it interconnects.
• Also known as a cable harness, it is more than just a collection of multiple wires put together.
• It manages the key functions around the engine including engine controller, oil controller gate, transmission plug housing, air pipe sensors, pressure sensors, and water temperature sensors.
• An engine wiring harness is how each part of your vehicle gets electricity.
• It is crucial to help the vehicle run and it’s usually made of a heat-resistant rubber to handle the high and low temperatures that vehicles often experience.
• The vehicle needs more than the engine, and it requires a lot of electricity for certain things to function, like the radio or lights.
• Beyond that, battery, starter, and even alternator run on power, which is provided by the engine. Without an engine wiring harness, we couldn’t start your vehicle.

How Does the Engine Wiring Harness Work?

• There are many cables in the engine wiring harness that work to connect electricity to your vehicle parts.
• This vehicle part has many sensors, and they work to ensure that everything in your vehicle is in working order.
• Some of these major systems in your car are fuel and transmission.
• When you get a check engine light, you have the engine wiring harness to thank.
• It works by using these cables and a fuse box.
• They wire the electricity produced by the engine to the various parts and sensors.
• It is created using high-temperature plastic or rubber because the engine heats up a lot.
• That could cause the engine wiring harness to melt over time.
• And while this is a rare occurrence, it does happen.
• Think of this part of the vehicle like the brain.
• Without it, it wouldn’t be possible to get the information your vehicle needs.
• It’s always working overtime to relay the data your vehicle needs to function correctly.
• Whenever a sensor goes off, it’s because the engine wiring harness alerted the sensor of the problem.
• The exciting thing is that as vehicles get more advanced, the engine wiring harness grows.
• Some say that new cars have over 100 pounds of wires, so imagine how many things could go wrong with that.
• In the past, there may not have been many issues.
• However, as things advance, there are more to go wrong.

Engine Wiring Harness protection

• Protecting the wires is crucial to the safety of the vehicle.
• Wires exposed to high temperatures, erosive chemicals and projectiles will be damaged leading to fires, brake failures and critical malfunctions.
• o prevent these issues, wires need to be bundled and covered.
• Install wiring insulation or heat shield sleeve material that can withstand direct contact with high-temperature surfaces and is flameproof.
• It needs to be a material built specifically for under hood automotive applications and withstand constant temperatures up to 125°C, or 257°F.
• There are many options for protecting the wires in a vehicle’s harness.
• Zip ties securely bundle wire together but offer little protection or insulation.
• Plastic conduits offer protection from rough surfaces, although they can add weight and are not as flexible as other options.
• Heat-shrink tubing provides protection from heat, moisture and chemicals.
• However, the application is time-consuming.
• Tape is another option for bundling and protecting wires.
• Tapes are more flexible and cost-effective than other bundling options because they can be used for protective wrapping, bundling and sealing.
• With a wide variety of backings and adhesives, tape can offer sound dampening, thermal and electrical insulation and abrasion protection of the same quality of the other methods.
• Additionally, tapes are more flexible, lighter and easier to apply than tubing or plastic conduit.

OBJECTIVE

• Define all the mechanical connectors electrically and save it in the Catalogue.
• Place all the connectors to the required positions on the given engine 3D CAD model
• Place P-Clamps and Fir Tree clips at the required position by following the packaging rules.
• Create the Wiring Harness Routing with all the electrically defined connectors and mounting equipments.
• Create branching points at required locations to create sub branches and connect to various connectors in the geometrical bundle.
• Apply Protection coverings as required.
• Create Wiring harness flattening for the final geometrical bundle.
• Using the drafting workbench, create a drawing sheet with the flattened wiring harness.

DESIGN METHODOLOGY

Step 1- download the engine CAD data and required connectors CAD data from the given source.

Step 2- Download the required Connectors from the source and convert the mechanical connectors electrically by using the electrical part design work bench by following below steps.

• First download the connectors and mounting clip from the given link source.
• Get into the mechanical part workbench to create required geometrical parameters.
• Create connector connection point and bundle connection point on the required sides of the CAD part.
• Create axis system on the connector connection point such a way that the Y coordinate facing normal to the connector face, X coordinate facing towards the locking mechanism and Z coordinate facing to the top.
• Create cavity connection point for connectors having the cavity for mounting clips

Using the geometrical parameters created,

• Define part as electrical connector.
• Define bundle connection point.
• Define connector connection point.
• Define cavity connection point.

2 pole connector

Inter Connection Connector (C-776438-4)

STEP 3- Download and Define the plastic channel electrically

• Procedure for electrically defining the Channel.
• Create bundle entry point and exit point.
• Create a line curve between the main entry and exit points for creating the multi-branchable using external curve inside the channel
• Create 8 bundle entry points on the openings for connecting the injector connectors.
• Using the geometrical parameters, define the channel electrical using the define mounting equipment option.
• Create define bundle entry points using the “define bundle connection point option".

Create Channel symmetrical assembly and define the symmetry bottom channel electrically using define mounting equipment option and also create all the required geometrical parameters on it.

STEP 4- download and define P-clamp, L-clamp and cavity clip.

STEP 5 – Creating the context assembly

• Context assembly is nothing but the product file which contains the engine 3D-CAD data and the engine harness geometrical bundle.
• Here the geometrical bundle product contains all the connectors and other mounting equipments, clips and clamps which are electrically defined for the assembly.
• Sheet metal L-clamp are added in the main context assembly.

The we need to switch into the electrical harness assembly workbench and Geometrical bundle product file should be electrically defined using the Define Geometrical bundle option before adding any parts into it.

The Given V16 engine 3D-CAD model requires a total of 23 connectors to be placed on it and an inter connection connector for the engine wiring harness assy. The connectors used in this engine are as follows

• 8 numbers of connectors are required on the fuel injector sensors on each cylinder head, i.e.; total 16 fuel injector sensor connectors are needed.
• Total 4 numbers of cam-shaft sensor connectors are needed.
• 1 neutral position sensor connector and 1 speed sensor connector on the gear box housing.
• 1 engine coolant temperature sensor placed at the center of engine.

STEP 8 – Adding all the other connectors for sensors like coolant heat sensor, neutral position sensor, speed sensors

STEP 9 – Placing the Interconnection connector and L-clamp support

However, situation of interconnection connectors are not similar to device connectors. Interconnection connectors are not parked with any device but should be pared with the help of clips/clamps/sheet metal brackets etc. possible to the packaging conditions.

Un parked connectors can create following issues-

• Rattling noise
• Physical damage to connectors
• Uncontrolled harness routing
• Manual errors during assembly because of undefined parking.

Assume the bundle connection from the chassis is coming from right side of the engine and therefore L-clamp is provided on the right side of the engine which provide proper support for the interconnection connector. Here the cavity clip is inserted into the hole provided on the L-clamp.

Additional slack should be provided to the chassis bundle connecting to the engine harness interconnection connector to protect the wiring harness from vibrations caused during the vehicle operation.

From the above pictures we can clearly see that the L - Clip is mounted to one of the holes provide on the Engine block for the screw and it is rested onto the ribs so that it restricts its rotational movement during tightening of the screw.

And also, we can see that the Interconnection Connector have been placed and it is Electrically connected with the cavity provided for it.

The L - Clip should be added to the main product as it is not a part of the Geometric bundle or the Wire harness bundle.

STEP 10 – Add P-clamps for proper Routing of the harness bundle

Adding supporting components like p-clamps and firtree clip can help the harness bundle provide proper routing and also help to prevent the harness bundles fouling from unwanted mechanical components.

• P - Clamp and the Fir Tree can be placed at required locations to ensure best possible routing for the harness bundles.
• The p – Clamps can be mounted to the holes provided on the Engine block in which the screws to tighten the Engine block.
• The Fir tree clips are positioned according to the requirement during the wire harness routing.
• After finalization of the routing, we can request the Engine design team to provide the holes for the Fir tree clips as per their location.

STEP 11 - Placement of Channels at the required Locations

Use of plastic guiding channels are recommended to meet the clearances in critical areas if it is difficult to achieve by use of clamps.

Some important packaging rules and best practices to be considered during wire harness routing and placing of the clips and clamps are as follows –

• Distance between two clamps on a straight branch should be minimum of 200mm.
• The minimum branch length should be 50mm.
• Minimum distance between clip and nearest branching point should be 25mm.
• The minimum distance between two straight connection points should be 200mm.
• The minimum distance between two breakout points should be 50mm.
• To limit the number of branches from a single branch point to 4.
• Avoid routing wiring harness near the exhaust manifold and its components and also from other unshielded heat sources. If re routing is not possible then maintain a minimum distance of 200mm.
• Try to avoid use of too many metal brackets on engine. Try to use the available threaded bosses on engine or demand for it.
• Enough clamps shall be provided to ensure positive clearance with surroundings and safety of wiring harness.
• P - Clamps, Fir tree clips and other clips can be added to the Geometric bundle as they are electrically defined and are part of the Wire harness routing and should be provided with the Wire bundle package.
• Enough slack should be provided to the wiring harness which help not to get damaged during the Engine rocking or starting condition.
• The wire harness routing should be done in such a way that it is easy in manufacturing and serviceability.
• The wire routing should be done keeping in mind the cost effectiveness of the bundle package.
• To avoid the harness routing and clipping in blind zones of the operator during the assembly and the service.
• To provide proper slack at end connectors so that there will be no tension on the wire bundle.
• To avoid sharp edges on the sheet metal parts and if it is not possible then provide protection parts to prevent damage of the wire bundle.
• To provide separate branch points for separate connectors to ensure Poka-Yoke.

Keeping all the above packaging rules we can start the routing of the wire and provide clipping and clamping wherever necessary during the routing process.

ENGINE with all the components for wiring harness routing

Final product

WIRING HARNESS FLATTENING

Wiring harness Bundle packaging process is done. Now we need to convert the geometrical bundle into a flattened wiring harness in the Electrical Harness Flattening Workbench.

• To create the Flattened Harness, we need to create a new product file and switch into the electrical harness flattening workbench.
• Now we need to define the Harness Flattening Parameters and then Extract the geometric bundle from the wiring harness context product file.
• Then select all the branches and flatten the entire Geometric bundle.

• The bundles can be rotated and rolled with a proper radius in order to fit the drawing sheet.

 FLATTENED HARNESS VIEW IN THE DRAWING SHEET

Conclusion

In this project i have successfully routed the  wiring harness for the V16 Engine assembly and the flatten-view drawing was prepared in CATIA V5. Various packaging rules and constraints were considered while routing the harness. After finalizing the wire routing, we can request the corresponding Engine design team to provide additional holes for the mounting of Fir tree clips.