Designing a Parallel Hybrid Powertrain Architecture for Improved Fuel Efficiency

Module Learning Outcomes Assessed:

1. Appraise the use of battery technology in hybrid and hybrid electric vehicle systems.

2. Apply concepts of traditional engine technology and alternative propulsion systems along with battery technology to design and develop various hybrid engine layouts

3. Develop numerical skills regarding the engine performance and the methods to optimise the engine performance.

4. Determine the size and governing parameters of an internal combustion engine to meet given criteria and select, by calculation, gear ratios to assume required vehicle performance from given engine characteristics.

Aims

To modify a passenger vehicle powertrain system by adding an electrical propulsion system and using parallel hybrid powertrain architecture. Technical considerations shall include the overall vehicle performance and efficiency. Additionally, the hybrid vehicle system to be designed with an improved fuel consumption and have the same vehicle acceleration performance as per baseline vehicle.  

Engine characteristics analysis

You will need to perform an analysis on the baseline vehicle according to the engine Brake Specific Fuel Consumption (BSFC)  There are three data available in Moodle page:

• Engine data at part load and full load
• Vehicle parameters and transmission ratios
• Standard vehicle duty cycles

Fuel Heating Value is 43.4 MJ/kg for Petrol and 42.6 MJ/kg for Diesel

Using ARTEMIS R130 as the standard test drive cycle, the following vehicle attributes need to be defined for benchmarking exercise:

1. Plot the powertrain-vehicle architecture and show the interaction of the sub-systems; (2%)
2. Plot the engine power demand and engine torque demand in at every time step; (2%)
3. Determine the total energy requirement per drive cycle;  (2%)                                                                                                                                                        
4. Average fuel consumption in litre/100km and CO₂ emission in gram/km; (2%)
5. Determine the instantaneous fuel consumption on the BSFC map; (2%)
6. Plot the graph and value for vehicle standing start acceleration (0 – 100km/h) and engine torque value in time domain; (2%)
7. Vehicle maximum speed in km/h; (2%)
8. Vehicle maximum gradeability; (2%)
9. Calculate at every engine operating condition on the drive cycle;   
10. Engine thermal efficiency;  (2%)
11. Engine mechanical efficiency. Explain the assumptions made for the engine parameters consideration. (3%)
12. Propose a strategy to improve the engine thermal efficiency; (7%)
13. Design the optimal control to improve the engine performance by 5% through air path AND fuel path calibration methods. (7%)    

Define the component specifications and the operation strategy of the hybrid powertrain. Evaluate the performance of the vehicle based on new powertrain architecture.

Design an hybrid electric propulsion system (35%)

Using parallel hybrid architecture, evaluate the required specifications for the electric motor, the motor controller and the batteries. Provide the evidence and the explanations for the selected components specifications.

1. Electric motor: What are the minimum performance of the motor.  Identify the suitable motor in the market. How is it connected to the wheels; (8%)                                        

2. Batteries: What is the design power output and energy capacity. Identify the available battery cell in the market and the battery cell architecture. (Note: only 10-90% of the battery capacity can be utilized). Specification limitations:  the design working envelope for the battery size is less than 80 litre to provide  the desired battery energy capacity and the maximum operating voltage is less than 600V due to the limitation of auxiliary High Voltage safety components; (8%)

3. Motor controller minimum specifications; (4%)

4. Engine: Discuss the methods and the technologies for engine downsizing. What are the drawback of engine downsizing:                                                                                                                               (7%)                                                              

5. Define and discuss the strategy of operation of the two energy systems. What are the expected benefits in fuel consumption. Plot a schematic diagram of the components in the vehicle.  (8%)

Design a parallel hybrid powertrain architecture and analysis (30%)

Model the parallel hybrid powertrain architecture in Excel. Based on this model:

1. Analyse and compare the parallel hybrid powertrain with the bench mark data for:
2. Vehicle standing start acceleration from 0-100 km/h and plot the graph;  (3%)
3. Vehicle maximum speed in km/h (3%)
4. In the drive cycle :
5. Plot the battery State-of-Charge (SOC) value in the drive cycle; (3%)
6. Discuss the energy consumption of fuel and battery; (3%)
7. Propose the strategy to improve the energy consumption. The battery pack must be charged back to its original SOC at the end of the drive cycle;  (3%)
8. Demonstrate the BSFC map utilisation; (3%)
9. Discuss the effectiveness of the proposed system; (3%)
10. Compare the fuel consumption and CO₂emission to the benchmark values. (3%)                                                                                           
11. Check the performance of the components do not exceed the specifications in the drive cycle;
12. Calculate the electric range ONLYand the assumptions made;  (3%)                        
13. Plot a pie chart of mechanical energy output distribution of the powertrain during the drive cycle (i.e. motor, gearbox, motor controller, batteries, rolling and aerodynamic resistance). Discuss the observations made. (3%)

• For the Driving Cycle simulation use a time step of Δt=1.0s
• For the standing start acceleration simulation (0-100km/h) use a time step of Δt=0.1s
• Maximum speed can be calculated by the available power from the powertrain compared to the resistance of the travelling vehicle at different speeds. The theoretical maximum speed can be used to estimate the motor power specifications.
• The software to be used is Microsoft Excel.

This is an engineering report requiring adequate formatting.

Marks will be allocated for referenced material and appropriate discussion. Estimations of the fuel consumption and the acceleration results according to literature will not be accepted. You Must use

the BSFC maps provided to calculate the fuel consumption. A figure that demonstrates the operating points of the engine on BSFC map used in the model MUST be provided in the submitted model to validate your results. ALL results must be referred to your submitted models. Battery SOC must demonstrate the change in value during the drive cycle run. The model is considered incomplete without the SOC value. Every objective component must be clearly identified in the report.

All relevant data must be in the report for marking.

Peer assessment submission is required as part of individual mark separation. It is submitted individually and confidentially through Moodle marking out of 100% the effort of the other team members