D. W. Lyons

CLASS 8 TRUCK EMISSIONS TESTING: EFFECTS OF TEST CYCLES AND DATA ON BIODIESEL OPERATION

Design of cycles for chassis emissions testing of heavy duty trucks is in its infancy, and no cycle truly nrepresentative of in-use behavior of trucks with manual transmissions is currently available. Class 8 tractors were tested nfor emissions using two Transportable Heavy Duty chassis dynamometer systems. The vehicles were tested on diesel and nbiodiesel using the West Virginia University WVU 5 peak cycle, which has prescribed accelerations, cruise sections, and ndecelerations and covers a 5 mile (8 km) distance. Also, a test cycle that was similar, but employed maximum acceleration nrates under the control of the driver was used: this was termed the “ WVU 5 mile route”. Emissions of carbon monoxide n(CO) and particulate matter (PM) were substantially higher for the WVU 5 mile route than for the WVU 5 peak cycle, nwhich can be explained in terms of air:fuel ratio. Emissions of hydrocarbons (HC) and oxides of nitrogen (NOx) were less naffected. The WVU 5 mile route may be favored in the future in that it examines full load emissions. To compare emissions nbetween vehicles fueled with No. 2 diesel (D2) and a blend of 65% D2 with 35% soy biodiesel (BD35), eight class 8 ntractors were operated through the WVU 5 peak cycle. Emissions of CO, HC and PM were lower on average for the nBD35 when used in newer Detroit Diesel Series 60 350 hp (261 kW) engines and 1989 Cummins 855 in.3 (14 L) 315 hp n(235 kW) engines, but for 1989 Mack E-6 350 hp (261 kW) engines, only CO was lower. Emissions of NOx were slightly nhigher on average for all three-engine types with the BD35. Differences in many cases were small, as were sample sizes, nso that additional data is desirable before reaching definitive conclusions.

ENERGY CONSUMPTION ANALYSIS OF HEAVY-DUTY VEHICLES FOR TRANSIENT EMISSIONS EVALUATION ON CHASSIS DYNAMOMETER

Abstract In order to acquire vehicle emissions and fuel economy by driving a vehicle on a chassis dynamometer, it is imperative that the chassis dynamometer should exactly simulate the road experience of the vehicle. In this paper, the modelling of a heavy-duty vehicle energy consumption both on the road and on a chassis dynamometer was developed and implemented by using two driving cycles. Road coast-down tests of a vehicle were conducted to obtain a road load equation of the vehicle. Its companion chassis dynamometer coast-down tests were aimed to estimate the characteristics of the dynamometer-vehicle system. Power absorber settings were achieved that duplicate the vehicle road load in the dynamometer testing. Comparing the measured energy of the vehicle between driving cycles on the chassis dynamometer and the calculated energy on the road, it is shown that the West Virginia University (WVU) transportable heavy-duty chassis dynamometer is successful in simulating the vehicle road load conditions when conducting emissions testing.

Finite element design of manipulator-coupled spacecraft for a research testbed

This paper describes the design and analysis of a research testbed developed to study the control of manipulator-coupled spacecraft with independent attitude control systems. This scenario could present itself in the assembly of Space Station Freedom (SSF). SSF assembly calls for a rendezvous of the Space Shuttle (SS) with SSF. Part of the assembly process requires that both spacecraft be coupled via the Space Shuttle Remote Manipulator System. An additional criterion that poses increased complexity is that the Space Shuttle controls and Space Station controls can not communicate. The technical issue involved is unwanted vibrations of the coupled-configuration that occur retraction and the complications due to non-interacting control systems. To understand these vibrations and possible complications, a research testbed has been built at the Marshall Space Flight Center in Huntsville, AL.To build the testbed, the manipulator links joints, and vehicles that represent the Space Shuttle and Space Station had to be designed. Pre-design simulation studies using ANSYS [1] (a Finite Element Computer Code) is used to size and design the manipulator links for the experimental facility. The ANSYS results were verified by the development of the Lagrangian Equations of motion. The Harmonic drives used as joints for the two link, three joint manipulator have been dissected into free body diagrams to ensure proper load paths in the ANSYS models. Accurate simulation of manipulator-coupled spacecraft is an important technology for NASA to understand. This paper outlines the methodology behind the preliminary design of a research testbed developed to help NASA gain knowledge in this area.