A Survey of Technology for Hybrid Vehicle Auxiliary Power Units.
Interim rept. Apr 94-Jun 95,
SOUTHWEST RESEARCH INST SAN ANTONIO TX
Pagination or Media Count:
The state-of-the-art of heat engines for use as auxiliary power units in hybrid vehicles is surveyed. The study considers reciprocating or rotary heat engines, excluding gas turbines and fuel cells. The relative merits of various engine-generator concepts are compared. The concepts are ranked according to criteria tailored for a series-type hybrid drive. The two top APU concepts were the free-piston enginelinear generator FPELG and the Wankel rotary engine. The FPELG is highly ranked primarily because of thermal efficiency cost, producibility. reliability, and transient response advantages it is a high risk concept because of unproven technology. The Wankel engine is proven. with high power density, low cost and low noise. Four additional competitive concepts include two-stroke spark-ignition engine. two-stroke gas generator with turboalternator, free-piston engine gas generator with turboalternator, and homogeneous charge compression ignition engine. This study recommends additional work, including cycle simulation development and preliminary design to better quantify thermal efficiency and power density. Auxiliary concepts were also considered, including two which warrant further study electrically actuated valves, and lean turndown of a normally stoichiometric engine. These concepts should be evaluated by retrofitting to existing engines.
- Reciprocating and Rotating Engines