Supercharged internal combustion engine

Abstract

A supercharged internal combustion engine system wherein the supercharger assembly includes an ejector pump driven by high-pressure air for pumping intake air into engine combustion chamber. Included are means for sensing engine power demand and controlling the supercharging action. A compressor and an air tank for providing high-pressure air for driving the ejector pump are also disclosed. During periods of natural aspiration the ejector pump can be by-passed to reduce flow impedance. The ejector pump can use a driving nozzle with a fixed throat or a variable throat, or a lobed nozzle. Effective supercharging is achieved even at low engine speeds. One of the objects of the invention is to obtain more power from small displacement ICE and thus providing automotive vehicles with sufficient acceleration in addition to good fuel economy.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Not Applicable FEDERALLY SPONSORED RESEARCH [0002] Not Applicable Sequence Listing or Program: [0003] Not Applicable FIELD OF THE INVENTION [0004] The present invention relates to a supercharged internal combustion engine where engine intake air is pumped by an ejector pump operated by high-pressure air to boost engine output during increased power demand conditions. BACKGROUND OF THE INVENTION [0005] Overview: The current emphasis on fuel economy in the design of power plants for automotive application motivates the efforts to improve the performance of internal combustion engines (ICE) with relatively small displacement. It is well known that automotive vehicles with small displacement engines enjoy moderate fuel usage. However, under high torque conditions such as acceleration and grade ascent, small displacement ICE's often fail to provide satisfactory power. Yet, the conditions demanding high torque generally represent only about o...

AI Technical Summary

Benefits of technology

[0030] It is still another object of the invention to obtain more power from small displacement ICE and thus providing automotive vehicles with sufficient acceleration in addition to good fuel economy.

[0031] It is a further object of the invention to provide a booster stage for a conventional supercharger (engine-driven

Problems solved by technology

However, under high torque conditions such as acceleration and grade ascent, small displacement ICE's often fail to provide satisfactory power.

Yet, the conditions demanding high torque generally represent only about one tenth of a vehicle operating time.

Engine-driven superchargers with nonpositive displacement compressors (i.e., turbine-type) were developed (as disclosed, for example, by Hall-Brown in U.S. Pat. No. 1,645,178) but did not provide adequate flow at low engine speeds associated with high torque conditions.

Compression in a supercharger heats up the intake air, thereby reducing its density and adversely impacting ICE performance.

These pumps are expensive since they use precision machined and accurately aligned rotor components.

Pump rotors spin at high speeds, typically in the range of 5,000 to 20,000 revolutions per minute (rpm), which leads to vibrations and wear.

Abrasion and wear gradually increase the precision clearances between mating rotor components which results in reduced supercharger performance.

Another limitation of engine-driven superchargers is the low volumetric output at low engine speeds.

This can be remedied by a variable speed drive, but only at a significant increase in complexity and cost.

Engine-driven superchargers also occupy a relatively large volume which complicates their integration into engine frame.

While being more space efficient, integral supercharger obstructs other ICE components and impedes ICE serviceability.

Engine-driven supercharger requires significant ICE power to operate and this power must be supplied at the least opportune moment, namely during high demand on ICE output, thus reducing ICE output power available for propulsion.

This often requires a complex control system.

However, turbochargers must run at very high rotational speeds (typically on the order of 20,000 to 100,000 rpm) and use sophisticated engineered materials to withstand the high temperatures of ICE exhaust, both of which requires rather costly construction.

Another disadvantage of turbochargers is a relatively long response time lag cased by

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