A generalized IC engine propulsion method and corresponding transmission design for improving vehicle fuel efficiency

摘要

Abstract Based on the analysis of the working profiles of internal combustion (IC) engines, a case-emphasized propulsion method is generalized to improve vehicle fuel efficiency. With this method, the ratio of the most-used speed to the most-desired speed of an IC engine is employed to control the engine to always run at its optimal working state with an efficient single-stage gear transmission. Examples of the propulsion method with different brands of IC engines in the market place demonstrate the potential that this method could reduce engine fuel consumption up to 5?~?39?%. A conceptual design of n-ratio automatic single-stage gear transmission is then developed to implement the case-emphasized propulsion method in a general way. Not only can such a design execute the proposed propulsion method well as an almost continuous variable transmission, but it can also increase the propulsion efficiency about 8?~?18?% if it is applied to replace the traditional automatic transmissions or continuously variable transmissions (CVTs) in vehicle drivetrains.