What problem does the staged opening of throttle valves 64 and 77 solve?

It reduces the valley in the engine's torque curve; keeping valve 77 closed until speed n1 and opening valves 64 at speed n2 produces improved torque curves (P2 and P3) and significantly improved performance.

How are the longer intake passages 81 and 82 made longer?

By appropriately curving them, by having them enter the plenum chamber at a different location, or by utilizing both of these expedients.

Which cylinders are served by plenum chambers 45 and 46?

Plenum chamber 45 serves cylinders 15, 16 and 17 via longer passages 81, and plenum chamber 46 serves cylinders 18, 19 and 21 via passages 82; the high-speed passages with throttle valves 64 serve the same cylinder groups.

What does claim 1 of the patent cover?

An induction system with at least two variable volume chambers, a plenum chamber, first and second intake passages, a flow control valve operable in response to an engine running characteristic, first and second atmospheric air inlets, and throttle valve means controlling flow into the plenum chamber through each inlet.

What do claims 5 and 6 add to the induction system?

That the atmospheric air inlets have different effective cross-sectional areas.

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Engine Induction System Patent Text - Dual Plenum Intake & Throttle Staging (2001)

Induction system patent claims and torque-curve text page Super Ford Summer 2001

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Text-only magazine page with patent claims describing a multi-stage variable induction system and how staged throttle valve opening fills the dip in the engine torque curve.

AI caption August 2007 · Photo 938 of 1028

This is page 16 of the Summer 2001 issue of a newsletter ("S H & Tell"), reprinting the concluding portion of a patent describing an induction system for an internal combustion engine. The text explains how staged opening of throttle valves (referenced as valves 64 and 77) at engine speeds n1 and n2 reduces the 'valley' in the engine's torque curve, producing improved torque curves labeled P1, P2, and P3 in the patent's FIG. 6. It then describes an alternate embodiment (FIG. 4) using dual plenum chambers (45 and 46) with high-speed intake passages and longer intake passages (81 and 82) serving cylinder groups 15/16/17 and 18/19/21 respectively, where passage length is varied by curving passages or changing their plenum entry location. The page concludes with the patent's claims section, listing claims 1 through 6 covering an induction system with variable volume chambers, a plenum chamber, first and second intake passages, a flow control valve responsive to engine running characteristics, first and second atmospheric air inlets, and throttle valve means, with dependent claims covering separate throttle valves, different longitudinal inlet locations, and different effective cross-sectional areas of the air inlets. A reader learns the technical rationale for staged multi-throttle, dual-plenum variable-length intake systems and the exact patent claim language.

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Frequently asked questions

What problem does the staged opening of throttle valves 64 and 77 solve?: It reduces the valley in the engine's torque curve; keeping valve 77 closed until speed n1 and opening valves 64 at speed n2 produces improved torque curves (P2 and P3) and significantly improved performance.
How are the longer intake passages 81 and 82 made longer?: By appropriately curving them, by having them enter the plenum chamber at a different location, or by utilizing both of these expedients.
Which cylinders are served by plenum chambers 45 and 46?: Plenum chamber 45 serves cylinders 15, 16 and 17 via longer passages 81, and plenum chamber 46 serves cylinders 18, 19 and 21 via passages 82; the high-speed passages with throttle valves 64 serve the same cylinder groups.
What does claim 1 of the patent cover?: An induction system with at least two variable volume chambers, a plenum chamber, first and second intake passages, a flow control valve operable in response to an engine running characteristic, first and second atmospheric air inlets, and throttle valve means controlling flow into the plenum chamber through each inlet.
What do claims 5 and 6 add to the induction system?: That the atmospheric air inlets have different effective cross-sectional areas.