Date of Graduation

2013

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Scott Wayne

Committee Member

Higel Clark

Committee Member

Hailin Li

Committee Member

Chris Atkinson

Committee Member

Natalia Schmid

Abstract

Automotive transportation consumes more than 71% of the world's total petroleum energy. The vehicle will have to use less because it will take less than 30 years to consume the rest of the proven conventional oil reservoir if the fuel consumption keeps the current trend. One of the methods to improve the vehicle efficiency is to develop Hybrid Electric Vehicle (HEV). An HEV combines an internal combustion engine (ICE) and electric motor(s) powered by batteries or capacitors to achieve better fuel economy. Among the HEVs, 2-Mode HEV combines an ICE and two electric motors with two planetary gear sets and allows the vehicle to operate in two Electrically Variable Transmission (EVT) modes with better fuel economy in both low speed range and high speed range.

A prototype 2-Mode HEV powertrain was developed and included a 1.3 liter 4-cylinder turbocharger diesel engine, a 2-Mode front wheel drive transmission and a 330 V 12.9 kWh high voltage battery. A forward-looking quasi-static model of the 2-Mode HEV was developed and parameterized with bench test data to evaluate the vehicle performance and fuel economy. A rule-based hybrid control algorithm was implemented to achieve engine stop-start, transmission shifting, high voltage battery charge sustaining, optimal engine speed and torque control, vehicle propulsion and regenerative braking. The prototype 2-Mode HEV was tested on road to verify vehicle safety features, acceleration and braking capability, autocross time, towing capacity and combined city and highway drive capability. Local city and highway drive schedules comparable to the UDDS and HWFET drive schedules were developed to test the vehicle's fuel economy.

The vehicle on-road test reached 24.5/31.5 MPG fuel economy, which was 23.8% higher than the mule vehicle, 19.0/26.0 MPG. The vehicle was tested on road to evaluate the loss of the performance. The vehicle achieved 16 s during the 0-60 mph acceleration and 10 s during the 50-70 mph acceleration, both of which were 1.4 s longer than the mule vehicle. The braking distance from 60-0 mph was 148.5 ft, which was the same as the mule vehicle. The vehicle demonstrated the same towing ability at constant 45 mph speed with a 3.5% grade for 15 miles.

The 2-Mode hybrid powertrain with a turbocharger diesel engine demonstrated an alternative to sustain petroleum energy and reduce the petroleum oil dependence in automotive transportation with fuel economy improvement of 23.8%, but a small acceleration capability loss. The 2-Mode hybrid electric vehicle combined the strength and load capacity of conventional automatic transmission with the increased fuel economy provided by the hybrid electric vehicle architecture.

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