# Alternative Propulsion Systems

To modify a passenger vehicle (VW Golf 1.6L Naturally Aspired (N/A)) to a series hybrid powertrain system. Considerations will include overall performance and efficiency. Evaluate and engineer a hybrid system that will allow low fuel consumption and equivalent acceleration and top speed to the base model. (Base model specifications: Acceleration: 9s for 0-100km/h, top speed: 170km/h, 140g/km CO2 emissions, CDA: 0.77, vehicle mass 1000kg + [the last 3 digits of your SID] and range 150km)

• Design the hybrid system: (60%)

According to the serial hybrid architecture, evaluate the required specifications for the motor, batteries and Range Extender (REx). You need to demonstrate evidence of reasoning for the specifications selected.

1. Electric motor: Does it have enough power to reach top speed and accelerate within the required time frame? Justify. (10%)
2. Batteries: what is the designed power output and energy capacity? Justify. (20%)
3. Define the sweet points to operate the REx. What is the power output of the REx? Use the example in Moodle for power scaling to identify BSFC map. Justify.   (20%)
4. Define the specifications of generator and its inverter. Illustrate the architecture of the hybrid system (10%)
• Perform analysis of your vehicle using your Excel model based on first principles: (40%)

Build your hybrid powertrain model in Excel based on its first principles. Extract and discuss the below required data.

1. What is the acceleration time (0-100km/h) and maximum longitudinal acceleration of the hybrid vehicle? What is the achievable top speed of the vehicle? Analyse the assumptions. (10%)
2. Using the REx to recharge the battery back to its initial SOC, what is the fuel consumption and CO2 emissions of the vehicle? Demonstrate the battery SOC utilisation and discuss its behaviour (20%)
3. Extrapolating the electric only energy consumption during the drive cycle, what is the electric only range of the vehicle? (10%)

Modelling considerations:

• For the Worldwide Harmonised Light Vehicles Test Procedure (WLTP) Class 3 Driving Cycle simulation use a time step of Δt=1.0s
• For acceleration simulation (0-100km/h) use a time step of Δt=0.1s
• Top speed can be calculated by the available power from the powertrain compared to the resistance of the travelling vehicle at different speeds. The theoretical top speed can be used to estimate motor power specifications.
• The software to be used is Microsoft Excel.
• The limits of the state of charge of the accumulator to be used are: 30-70% of its capacity.

Report considerations

This is an engineering report requiring adequate formatting.

Marks will be allocated for referenced material and appropriate discussion. Estimations of fuel consumption and acceleration results according to literature will not be accepted. You MUST use the brake specific fuel consumption (BSFC) maps provided to calculate fuel consumption. A figure demonstrating the operating points of the engine on BSFC map used in the model MUST be provided in the model to validate your results. ALL results must be referenced from your submitted models. Battery SOC must be demonstrated how it is changing during the drive cycle as without it the model is considered incomplete. Every objective componented must be clearly identified in the report. Your Excel model if for validation. All relevant data must be in the report for marking