Thermal Management for the 21st Century - Improved Thermal Control & amp; Fuel Economy in an Army Medium Tactical Vehicle

Abstract

A Stewart & Stevenson M1084A1 FMTV 5-ton cargo truck was used as the subject of a study to evaluate advanced powertrain thermal management components and subsystems. Funded by the U.S. Army TACOM and the National Automotive Center (NAC) under a Small Business Innovative Research grant (SBIR Phase II), the project focused on improving thermal management of the vehicle while reducing the peak fuel consumption by >10% in a vehicle having limited ram air cooling. The FMTV was used as a surrogate test bed to investigate thermal management technologies that could be applied to vehicles with confined package space, such as light armored vehicles.The vehicle was equipped with a thermal management system featuring distributed system architecture, electric coolant pumps and fans, electronic control valve, multiple air-cooled heat exchangers, and an electronic control system with PID feedback. The entire thermal management system was mounted in a metal enclosure behind the truck cab. The cab blocked the flow of ram air to the heat exchangers to simulate the confined space requirements.The production vehicle cooling system was fully instrumented to establish the baseline performance. Steady-state testing was performed in a climatic wind tunnel over a wide range of speed, load, and temperature conditions. The tests were repeated in the same facility under the same conditions after the new thermal management system was installed in the vehicle. Qualitative comparisons were made through road tests as well.Test results showed that the stability of the fluid temperature of the powertrain systems was significantly improved over the baseline and that the transmission oil temperature warmed to 80°C in nearly half the time required by the base system. The steady-state fuel economy increased by 5-20% over the base vehicle, depending on the speed/load point. A computer model was used to evaluate the performance of the vehicle over a simulated off-road driving cycle. The model results showed fuel economy gains over the base vehicle of 0.57 mpg (15.6%).

Investigation of coolant flow distribution and the effects of cavitation on water pump performance in an automotive cooling system

“…By doing so, the radiator could be downsized, the cooling efficiency could be improved, and the pump revolutions could be Figure 12. Static efficiency of the water pump for various coolant temperatures, computed using Equation (4). The coolant containing 50% of EG was used.…”

Feasibility study on a novel cooling technique using a phase change material in an automotive engine

“…While reducing the cooling system size and weight, several efforts have been attempted to handle increased heat load on the system with innovative cooling strategies such as reverse cooling, split cooling, and nucleate boiling cooling [2]. A number of researchers have also proposed replacing the conventional water pump with an electrically-driven pump that can actively control the coolant flow rate based on the optimum driving temperature [3][4][5][6][7][8]. This concept is beneficial for reducing parasitic losses of engine power and downsizing the whole engine cooling system.…”

A Strategic Investigation for Fuel Economy Improvement of Medium-Duty Tactical Truck: Preliminary Simulation and Experimental Results

“…This project adopts the driving cycle of [14,18] which is created from portions of the Munson Road course at the Aberdeen Proving Ground and a modified U.S. Environmental Protection Agency (EPA) driving schedule [19]. Shown in Figure 5, a typical mission schedule of the LMTV includes the beginning segments of varying vehicle speed over flat terrain with frequent accelerations and decelerations (the primary and secondary roads), and then a segment with varying grades at a constant vehicle speed (cross-country road).…”