Diesel Engine Test Bed
Most remote Alaskan villages depend on diesel engines to generate electricity. The price for diesel fuels has increased dramatically in the last five years, and future projections do not suggest that this strain on village economies will decrease. These high costs have increased interest in enhancing diesel engine efficiency and effective waste heat recovery, and testing alternative fuels and fuel augmentation strategies.
In order to address these issues, the Alaska Center for Energy and Power (ACEP) maintains and operates a Diesel Engine Test Bed at the University of Alaska, Fairbanks. The initial funding for this test bed came from a project to test Fischer Tropsches synthetic fuels, but subsequent testing has been conducted on fish oil biodiesel, hydrogen augmentation, propane augmentation, and waste heat recovery from the engine exhaust. What distinguishes our Diesel Engine Test Bed from an ordinary diesel electric generator is its instrumentation, designed to measure and modify a number of engine parameters and settings, and the subsequent analysis of this data.
The purpose of our Diesel Engine Test Bed is to demonstrate, test and document diesel engine and fuel parameters that can help improve engine efficiency in Alaskan villages. The diesel engine is representative of those found in village power houses throughout the state. ACEP’s facility is designed to examine diesel engine operation in depth and enables us to perform an energy balance on the operating engine, quantify efficiency, and document effects of altering engine parameters such as fuel type and fuel injection timing. Exhaust emissions, the real time pressure changes within a cylinder during a combustion event and engine vibrations are other parameters that are measured and recorded.
The mechanical core of our diesel test bed is a 4 cylinder Detroit Diesel Series 50, turbocharged, industrial duty diesel engine operating at 1200 RPM coupled to a 125 kW 3-phase 208 volt electric generator. The engine incorporates a Detroit Diesel electronically controlled unit injectors for fuel delivery, and data from the engine control system is collected by the data acquisition system. Combustion events within a cylinder are monitored by a Kistler piezoelectric pressure transducer installed in the #3 cylinder. The vibration signatures of the engine are measured by Dytran accelerometers mounted on the engine block. Fuel flow and air flow are measured with external flow meters. The electrical load is a 250 kW LoadTec load programmable load bank.
Data acquisition and control functions are provided by a National Instruments Labview system using a PXI embedded controller with multiple signal input and output modules.
The data acquisition and control system monitors temperatures, pressures, air and gas flows in real time. The system also interfaces with the programmable load bank, cylinder pressure transducer, vibration sensors, engine CANBus system, and the Detroit Diesel Electronic Control system.