Rudolf H. Stanglmaier

The Heavy-Duty Gasoline Engine - An Alternative to Meet Emissions Standards of Tomorrow

A technology path has been identified for development of a high efficiency, durable, gasoline engine, targeted at achieving performance and emissions levels necessary to meet heavy-duty, on-road standards of the foreseeable, future. Initial experimental and numerical results for the proposed technology concept are presented. This work summarizes internal research efforts conducted at Southwest Research Institute. An alternative combustion system has been numerically and experimentally examined. The engine utilizes gasoline as the fuel, with a combination of enabling technologies to provide high efficiency operation at ultra-low emissions levels. The concept is based upon very highly-dilute combustion of gasoline at high compression ratio and boost levels. Results from the experimental program have demonstrated engine-out NO x emissions of 0.06 g/hp/hr, at single-cylinder brake thermal efficiencies (BTE) above thirty-four percent. Multi-cylinder, 3-way catalyst equipped versions of this engine are estimated to provide NO x emissions of approximately 0.003 g/hp/hr at efficiencies approaching thirty-nine percent.

Measurement of the Percentage of Biodiesel in Blends With a Commercial Dielectric Fuel Sensor

Biodiesel is a nontoxic, biodegradable, and renewable fuel which can be made from vegetable oils. Most biodiesel used today is blended with petroleum diesel because lower level blends can be used in compression-ignition engines designed for conventional diesel fuel. Blending biodiesel with petroleum based diesel affects the physical properties of the fuel, which can have an impact on the performance of the engine. If the percentage of biodiesel in the fuel tank can be measured easily, it is possible to make engine adjustments to enhance the performance and emissions. In this project, a commercial fuel sensor was evaluated as a possible biodiesel percentage sensor. The Ford flexible fuel sensor was originally designed to measure the amount of ethanol in ethanol/gasoline blends. This resonant electromagnetic cavity sensor was used to determine the correlation between the output frequency and the percentage of biodiesel in blends of soybean oil biodiesel and No. 2 diesel fuel. Pure diesel fuel and soybean B100 were tested to serve as reference points. Soybean B100 from a different distributor and canola B100 were tested to investigate the effect of different biodiesel sources and types on output frequency. The output frequency of vegetable oil was also measured in order to consider the effect of using vegetable oil instead of biodiesel when trying to estimate blend percentage. The Ford flexible fuel sensor was capable of measuring the biodiesel percentage to within about ± 3%, and temperature changes between 10 and 50 °C produced no substantial change in this measurement. Emissions and performance measurements on a production diesel engine suggest that this sensor accuracy is sufficient to provide feedback for making adjustments to the engine operation.Copyright

Exploring the Potential Advantages of Light-Weight Valves in Internal Combustion Engines

This paper presents an investigation into the potential efficiency and performance improvements in an internal combustion engine by changing the mass and stiffness of valve train components, specifically the mass of the valve and the stiffness of the valve spring. Changes in valve mass affect the dynamic response of the valve train, so changes in other components must be made to maintain reliable and efficient engine operation. In order to quantify the potential benefits of lightweight engine valves, a dynamic model of the complete valve train system was developed. This model was experimentally validated on a motored engine in which the valve motion was measured for different combinations of valve mass, spring stiffness and engine speed. This paper describes the development and validation of the dynamic model, and discusses the effects of varying the valve mass and valve spring stiffness. It was found that a 75% reduction in the mass of the valves (as expected through the use of fiber reinforced composites) could reduce the maximum camshaft drive torque and frictional power by about 60–70%.© 2006 ASME

Design Process for Resin Transfer Molded, Fiber Reinforced Poppet Valves for Internal Combustion Engines

A project has been undertaken to design, build and test internal combustion engine poppet valves made from resin transfer molded (RTM) Fiber Reinforced Composites (FRCs). For poppet-valve engines, the valve train mass and stiffness is of particular importance because valve train natural frequency and the onset of valve float and bounce typically limit the engine operating speed. This in turn limits engine power and performance. FRC poppet valves offer the potential for substantial mass reduction as well as increased component stiffness. This enables reduced power consumption by the valve train, and increased overall engine efficiency. Resin transfer molding was chosen because of potential for high-volume production and near-net shape products. Valve design details include; identification of valve operating requirements, fiber orientations, material selection, and evaluation of potential solutions using computerized structural analysis. Mold design includes; mold configuration requirements, fiber placement strategies evaluated, intermediate validation testing done and initial prototype configuration. Results include the final valve design for an exhaust valve, fiber and matrix material selection, fiber placement strategy, and mold configuration. Plans for additional validation testing are presented.Copyright

Friction Reduction by Piston Ring Pack Modifications of a Lean-Burn Four-Stroke Natural Gas Engine: Experimental Results

A project to reduce frictional losses from natural gas engines is currently being carried out by a collaborative team from Waukesha Engine Dresser, Massachusetts Institute of Technology (MIT), and Colorado State University (CSU). This project is part of the Advanced Reciprocating Engine System (ARES) program led by the U.S. Department of Energy. Previous papers have discussed the computational tools used to evaluate pistonring/cylinder friction and described the effects of changing various ring pack parameters on engine friction. These computational tools were used to optimize the ring pack of a Waukesha VGF 18-liter engine, and this paper presents the experimental results obtained on the engine test bed. Measured reductions in friction mean effective pressure (FMEP) were observed with a low tension oil control ring (LTOCR) and a skewed barrel top ring (SBTR). A negative twist second ring (NTSR) was used to counteract the oil consumption increase due to the LTOCR. The LTOCR and SBTR each resulted in a ∼0.50% improvement in mechanical efficiency (η mech ).

Steady-State Intake Flow in a High-Performance V-Twin Engine

The design of intake ports for high-performance internal combustion engines has traditionally relied on steady-state flow benches and prototype core boxes. In this study, Computational Fluid Dynamics (CFD) methods were employed to gain further insight into the characteristics of a high-performance motorcycle engine. In this particular engine configuration, the throttle is located in very close proximity to the intake port, and the effects of throttle position on the intake flow characteristics were examined. This study shows that steady-state CFD analysis can be used in combination with traditional flow optimization techniques to provide further insight for cylinder head development. The intake flow behavior in this engine was found to vary considerably as a function of valve lift and throttle position. It was found that at low valve lifts the intake flow is relatively uniform around the periphery of the intake port, but at high valve lifts the flow into the cylinder is biased towards the top of the intake port. This results in a tendency to promote tumble at high valve lifts, but not at low valve lifts. Small throttle opening angles were found to magnify the flow biasing effect at high valve lifts.Copyright

Friction Reduction by Piston Ring Pack Modifications of a Lean-Burn 4-Stroke Natural Gas Engine: Experimental Results

A project to reduce frictional losses from natural gas engines is currently being carried out by a collaborative team from Waukesha Engine Dresser, Massachusetts Institute of Technology (MIT) and Colorado State University (CSU). This project is part of the Advanced Reciprocating Engine System (ARES) program led by the US Department of Energy. Previous papers have discussed the computational tools used to evaluate piston-ring/cylinder friction and described the effects of changing various ring pack parameters on engine friction. These computational tools were used to optimize the ring pack of a Waukesha VGF 18-liter engine, and this paper presents the experimental results obtained on the engine test bed. Measured reductions in friction mean effective pressure (FMEP) were observed with a low tension oil control ring (LTOCR) and a skewed barrel top ring (SBTR). A negative twist second ring (NTSR) was used to counteract the oil consumption increase due to the LTOCR. The LTOCR and SBTR each resulted in a ∼ 0.50% improvement in mechanical efficiency (ηmech ).Copyright

Tri-Axial Force Measurements on the Cylinder of a Motored SI Engine Operated on Lubricants of Differing Viscosity

Friction is a determining factor in the efficiency and performance of internal combustion engines. Losses in the form of friction work typically account for 10–20% of an engine’s output. Improvements in the friction characteristics of the power cylinder assembly are essential for reducing total engine friction and improving the mechanical efficiency of internal combustion engines. This paper describes the development and implementation of a new concept of the ‘floating liner’ engine at Colorado State University that allows 0.5 crank angle degree resolved measurement of the forces on the cylinder along 3 axes — in the axial direction, the thrust direction, and along the wrist pin. Three different lubricants with differing properties were tested to observe the friction characteristics of each. Experimental results showed that the floating liner engine was able to resolve changes in friction characteristics coinciding with changes in lubricant viscosity and temperature. Axial force increases at TDC and BDC were observed as lubricant viscosity was decreased and larger amounts of mixed and boundary lubrication began to occur. For each test the axial friction force data was used to calculate total cycle friction work. The thrust and off-axis (wrist pin direction) forces are discussed under the same circumstances.Copyright

Cycle-Controlled Water Injection for Steady-State and Transient Emissions Reduction From a Heavy-Duty Diesel Engine

A system for co-injecting mixtures of diesel fuel and water into a heavy-duty diesel engine has been developed and evaluated at the Southwest Research Institute. This system features prototype Lucas EUI injectors, full electronic control, and can vary the percentage of water in the mixture on a cycle-resolved basis. Tests of this system were conducted on a production Volvo D-12 engine, and have produced very encouraging results. Water-diesel co-injection yielded a considerable improvement in NOx-smoke and NOx-BSFC trade-offs under steady-state engine operation. In addition, control of the water percentage on a cycle-resolved basis was shown to be an effective method for mitigating NOx and smoke emissions over step-load transients. Results from this work show that a combination of aggressive EGR and diesel+water co-injection is very promising for producing very low levels of engine-out exhaust emissions, reducing the water storage requirements, and improving fuel efficiency. Further refinement of this injection technology is in progress.Copyright