Environmental concerns, legislative mandates, and operating costs are increasing demand for improved fuel economy for internal combustion engines. Some internal combustion engine systems bleed or divert a portion of pressurized air from an intake to the internal combustion engine into the inlet of an air compressor, reducing the overall work of the compressor for the same output. However, the use of pressurized intake air to drive flow into the air tank reduces fuel economy since boosted air is diverted from the intake to the engine, which is difficult to compensate for in engine controls, thus causing the engine to run at non-optimal fueling.
Furthermore, systems which provide non-boosted fresh airflow to the compressor require significant plumbing additions, which can affect the operating conditions of the engine. For example, turbocharged engine systems require plumbing to be added to provide a separate fresh air intake to the air compressor, and/or require plumbing additions at locations significantly spaced apart from the turbocharger compressor to avoid oil pull-over from the air compressor. These off-engine plumbing solutions require application-specific hardware design, thus creating a lack of continuity in the design and the need to develop new designs for new applications. These systems may also require separate filtration for the air compressor air supply, which increases ownership costs and decreases reliability. Therefore, further technological developments are desirable in this area.