US 10570866

US Patent 10570866, titled "Fuel injection throttle body," was issued to Holley Performance Products Inc..

Summary of US Patent 10570866:

• Title: Fuel injection throttle body
• Assignee: Holley Performance Products Inc.
• Inventors: Doug FLYNN, James DRALLE, Amy Gieske, Charles JENCKES, Corey Spainhoward
• Filing Date: May 22, 2018
• Issue Date: February 25, 2020
• Abstract: The patent describes a throttle body fuel injection system featuring a throttle body with at least one air intake. A fuel injector is connected to the throttle body at a fuel port, and an annular ring is coupled to the cylindrical inner wall of the air intake. This annular ring contains a primary fuel discharge orifice, located next to the fuel port, and multiple secondary fuel discharge orifices positioned radially around the ring. These orifices are designed to spray atomized fuel into the air intake.

Plain-Language Overview of Independent Claim:

• Independent Claim 1: This claim outlines a method for injecting fuel into an internal combustion engine that uses reciprocating pistons. The method involves:
  1. Providing a flow of air into an air intake of a throttle body equipped with annular fuel injection.
  2. Supplying fuel from an electronically controlled fuel injector. This fuel is directed through an annular channel to a single primary fuel discharge orifice and a number of secondary fuel discharge orifices. The primary orifice is specified as being larger than each of the secondary orifices. All these orifices are located in an annular ring within the air intake, positioned below the throttle plate.
  3. Atomizing and spraying the fuel, under positive pressure, into the air flow through both the primary and secondary fuel discharge orifices.

Litigation Information:

The Google Patents record for US10570866 indicates that the patent family has litigation, with a US case filed in the Tennessee Eastern District Court (Case: 1:26-cv-00059). Additionally, it notes the first worldwide family litigation has been filed. However, a direct search of CAFC 2026 dockets for the specific patent number 10570866 did not return any explicit results.

As of April 26, 2026, one known litigation case involves US patent 10570866, as identified in the Google Patents record for US10570866B2.

Known Litigation Involving US10570866:

• Jurisdiction: Tennessee Eastern District Court
• Case Number: 1:26-cv-00059
• Plaintiff(s): Not specified in the provided information.
• Defendant(s): Not specified in the provided information.
• Filing Date: Not specified in the provided information.
• Outcome or Current Status: The status is indicated as "litigation Critical," suggesting the case is ongoing or of significant importance within the patent family's legal history.

While the Google Patents record links to Unified Patents for additional details (https://portal.unifiedpatents.com/litigation/Tennessee%20Eastern%20District%20Court/case/1%3A26-cv-00059), specific information regarding the plaintiff(s), defendant(s), and filing date for this particular case involving US10570866 is not explicitly provided in the available patent text or supplementary search results.

Proceedings overview

The USPTO ODP API indicates no AIA trial proceedings for US Patent 10,570,866. A web search for PTAB proceedings related to US10570866 also did not surface any Inter Partes Review (IPR), Post-Grant Review (PGR), or Covered Business Method (CBM) trial proceedings.

This means there is no PTAB activity on file for US Patent 10,570,866.

Strategic summary

As of today, July 27, 2026, US Patent 10,570,866 has not been subjected to any AIA trial proceedings (IPR, PGR, or CBM).

• Claims: All claims (claims 1-6) of US10570866 are UNTESTED in the PTAB context. There have been no challenges to their patentability through AIA trials, meaning no claims have been canceled or explicitly sustained by a PTAB Final Written Decision.
• Estoppel landscape: Since no PTAB proceedings have occurred, there is no estoppel created under 35 U.S.C. § 315(e)(2). A defendant currently facing assertion of this patent could still raise any prior art ground (under § 102 or § 103) in a new IPR petition, subject to the statutory deadlines for filing such petitions.
• Pattern signals: The absence of PTAB activity suggests that either the patent has not yet been asserted widely enough to attract challenges, or that potential challengers have found the claims sufficiently robust or the economic incentive insufficient to warrant a PTAB petition. There is no pattern of filings, patent owner appeals, or involvement of defensive aggregators to report.

Recommended next steps

If you are a defendant facing assertion of US Patent 10,570,866, the following steps are recommended:

• Absence of PTAB Activity: The current absence of PTAB activity means that the claims have not been scrutinized in a trial-like setting at the USPTO. This could be seen as an opportunity for a challenger, as the patent has not been "hardened" by surviving IPRs.
• Consider a defensive IPR: If the patent is being asserted against you, evaluate the claims of US10570866 against relevant prior art to identify potential grounds for an Inter Partes Review (IPR) petition under 35 U.S.C. § 102 or § 103. The window for filing an IPR is typically one year from the date you are served with a complaint alleging infringement of the patent.
• Prior Art Search: Conduct a thorough prior art search, focusing on the technology described in US10570866, specifically the annular fuel distribution ring with primary and secondary fuel discharge orifices for atomizing fuel into the air intake. The patent's specification highlights its distinction from conventional factory TBI systems and most aftermarket TBI systems regarding fuel injector placement and spray pattern redirection.
• Monitor for future PTAB filings: Continuously monitor the PTAB E2E system for any newly filed petitions against US10570866, as this landscape can change rapidly.
• Engage with Patent Owner: Understand the patent owner's assertion strategy. The lack of PTAB history may influence settlement discussions or litigation strategy.

(No specific FWD to link to as no proceedings were found.)

Inventors

• Doug FLYNN (Holley Performance Products Inc.)
• James DRALLE (Holley Performance Products Inc.)
• Amy Gieske (Holley Performance Products Inc.)
• Charles JENCKES (Holley Performance Products Inc.)
• Corey Spainhoward (Holley Performance Products Inc.)

All inventors were associated with the original assignee, Holley Performance Products Inc., at the time of filing, as implied by the initial assignment record.

Original assignee

The original assignee named on the issued patent US10570866 is Holley Performance Products Inc.. Holley Performance Products Inc. is an operating company that designs, manufactures, and markets aftermarket automotive performance products, including fuel injection systems and throttle bodies. The patent describes a "Fuel injection throttle body" directly relevant to their primary line of business. Holley Performance Products Inc. ships products embodying the claims. The company is currently operating and listed as the "Current Assignee".

Assignment timeline

• 2014-01-14 (executed) / recorded 2018-05-23 — Reel 045886/0897
  • Conveyance: Assignment of Assignors Interest
  • Assignor: FLYNN, DOUG; DRALLE, JAMES; GIESKE, AMY; JENCKES, CHARLES; SPAINHOWARD, COREY (the inventors)
  • Assignee: HOLLEY PERFORMANCE PRODUCTS, INC., KENTUCKY
  • Correspondent: Not specified in the provided patent legal event data.
  • Context: Initial transfer of ownership from inventors to the operating company.
• 2018-10-26 (executed) / recorded 2018-11-06 — Reel 047429/0343
  • Conveyance: Security Interest
  • Assignor: FLOWMASTER, INC.; APR, LLC; ACCEL PERFORMANCE GROUP LLC; HOLLEY PERFORMANCE PRODUCTS INC.; HOLLEY PERFORMANCE SYSTEMS, INC.; MSD LLC; POWERTEQ LLC; RACEPAK LLC
  • Assignee: UBS AG, STAMFORD BRANCH, AS COLLATERAL AGENT, CONNECTICUT
  • Correspondent: Not specified in the provided patent legal event data.
  • Context: Grant of security interest by Holley (and related entities) to UBS AG.
• 2018-10-26 (executed) / recorded 2018-11-18 — Reel 048147/0510
  • Conveyance: Security Interest
  • Assignor: FLOWMASTER, INC.; APR, LLC; ACCEL PERFORMANCE GROUP LLC; HIGH PERFORMANCE INDUSTRIES, INC.; HOLLEY PERFORMANCE PRODUCTS INC.; HOLLEY PERFORMANCE SYSTEMS, INC.; MSD LLC; POWERTEQ LLC; RACEPAK LLC
  • Assignee: AEA DEBT MANAGEMENT LP, SECOND LIEN COLLATERAL AGENT, CONNECTICUT
  • Correspondent: Not specified in the provided patent legal event data.
  • Context: Grant of a second-lien security interest by Holley (and related entities) to AEA Debt Management LP.
• 2018-10-26 (executed) / recorded 2018-11-18 — Reel 048475/0125
  • Conveyance: Corrective Assignment (Security Interest)
  • Assignor: ACCEL PERFORMANCE GROUP LLC; APR, LLC; FLOWMASTER, INC.; HOLLEY PERFORMANCE PRODUCTS INC.; HOLLEY PERFORMANCE SYSTEMS, INC.; MSD LLC; POWERTEQ LLC; RACEPAK LLC
  • Assignee: UBS AG, STAMFORD BRANCH, AS COLLATERAL AGENT, CONNECTICUT
  • Correspondent: Not specified in the provided patent legal event data.
  • Context: Corrective assignment confirming the security interest previously recorded, likely due to an administrative error in the earlier filing.
• 2021-11-18 (executed) / recorded 2021-11-19 — Reel 058214/0174
  • Conveyance: Security Interest
  • Assignor: ACCEL PERFORMANCE GROUP LLC; B&M RACING & PERFORMANCE PRODUCTS INC.; DRAKE AUTOMOTIVE GROUP, LLC; HOLLEY PERFORMANCE PRODUCTS INC.; MSD LLC; POWERTEQ LLC
  • Assignee: WELLS FARGO BANK, NATIONAL ASSOCIATION, NORTH CAROLINA
  • Correspondent: Not specified in the provided patent legal event data.
  • Context: Grant of security interest by Holley (and related entities) to Wells Fargo Bank.
• 2021-11-18 (executed) / recorded 2021-11-24 — Reel 058944/0279
  • Conveyance: Release by Secured Party
  • Assignor: AEA DEBT MANAGEMENT LP, AS SECOND LIEN COLLATERAL AGENT
  • Assignee: ACCEL PERFORMANCE GROUP LLC, APR, LLC, FLOWMASTER, INC., HIGH PERFORMANCE INDUSTRIES, INC., HOLLEY PERFORMANCE PRODUCTS INC., HOLLEY PERFORMANCE SYSTEMS, INC., MSD LLC, POWERTEQ LLC, RACEPAK LLC
  • Correspondent: Not specified in the provided patent legal event data.
  • Context: Release of the second-lien security interest by AEA Debt Management LP, returning full rights to the assignees (Holley and its related entities).
• 2021-11-18 (executed) / recorded 2021-11-24 — Reel 058948/0926
  • Conveyance: Release by Secured Party
  • Assignor: UBS AG, STAMFORD BRANCH, AS FIRST LIEN COLLATERAL AGENT
  • Assignee: APR, LLC, POWERTEQ LLC, ACCEL PERFORMANCE GROUP LLC, HOLLEY PERFORMANCE PRODUCTS INC., HOLLEY PERFORMANCE SYSTEMS, INC., MSD LLC, FLOWMASTER, INC., RACEPAK LLC
  • Correspondent: Not specified in the provided patent legal event data.
  • Context: Release of the first-lien security interest by UBS AG, returning full rights to the assignees (Holley and its related entities).
• 2024-10-31 (executed) / recorded 2025-01-02 — Reel 069813/0457
  • Conveyance: Receiving Party Data Change of Address
  • Assignor: HOLLEY PERFORMANCE PRODUCTS, INC.
  • Assignee: HOLLEY PERFORMANCE PRODUCTS, INC., KENTUCKY
  • Correspondent: Not specified in the provided patent legal event data.
  • Context: Administrative record of a change of address for Holley Performance Products, Inc.

Timeline diagram

timeline
    title Ownership of US 10570866
    2014 : Inventors assigned to Holley
    2018 : Granted security int to UBS
         : Granted security int to AEA
         : Corrective security int for UBS
    2020 : Patent issued
    2021 : Granted security int to Wells Fargo
         : AEA released security interest
         : UBS released security interest
    2025 : Holley address change
    2026 : Litigation filed

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The patent's ownership consistently remains with Holley Performance Products Inc., an operating company. The other entities involved are financial institutions holding security interests, not licensing-only LLCs.
2. Known asserter in the chain — Not present. Holley Performance Products Inc., UBS AG, AEA Debt Management LP, and Wells Fargo Bank are not on the provided list of known NPEs or asserters.
3. Repeat correspondent across the chain — Unclear. The provided legal event data from Google Patents does not include correspondent attorney names, firms, or addresses for the recorded assignments. Therefore, it is not possible to assess this signal.
4. Cascading transfers — Not present. The initial assignment from inventors to Holley occurred in 2014 (executed). Subsequent entries are primarily security interests and releases, not transfers of ownership through chained LLCs. The security interests themselves involve multiple entities of the Holley corporate family, but these are financing arrangements, not ownership transfers to distinct shell entities.
5. Pre-litigation transfer — Not present. The first reported litigation ("US case filed in Tennessee Eastern District Court") indicates a filing date in 2026. The patent issued in February 2020, and the last ownership-related legal event (a change of address) occurred in January 2025. No assignments of ownership took place within six months prior to the 2026 litigation filing.
6. Bankruptcy fire-sale — Not present. The legal events show security interests and releases, typical of an active operating company managing its assets and liabilities, not a bankruptcy proceeding or a sale of assets due to bankruptcy.
7. Privateering — Unclear. There is no information within the provided patent text (legal events, description, etc.) to indicate privateering activity. This signal typically requires external sources like SEC filings or investigative reports, which are not available here.
8. Defensive aggregator (anti-NPE) — Not present. The chain of ownership and security interests does not terminate at any known defensive aggregators like RPX, Allied Security Trust, LOT Network, Unified Patents, or Open Invention Network.

Verdict

Operating-company assertion
This verdict is based on the consistent ownership of US10570866 by Holley Performance Products Inc. (an operating company producing products embodying the claims), as indicated by the initial assignment recorded on 2018-05-23 (Reel 045886/0897) and its current status as assignee. The other recorded legal events are security interests and releases, common financing activities for an operating company, rather than transfers to shell entities or known NPEs. The reported litigation commenced well after the patent issuance and the most recent administrative assignment event.

USPTO Assignment Center search: https://assignmentcenter.uspto.gov/ (search for patent number 10570866).

The user wants me to identify the most relevant prior art for US patent 10570866 and provide specific details for each. I previously decided to focus on eight highly relevant patents from the extensive citation list, based on their titles and publication dates prior to US10570866's priority date (2013-10-18). I will now present these.

US Patent 10570866: Fuel injection throttle body

Priority Date: 2013-10-18

Claims Summary of US10570866 (Key inventive aspects):
The core invention lies in a method for fuel injection into an internal combustion engine, specifically detailing a throttle body with annular fuel injection. This involves:

• An annular ring positioned within the air intake and beneath a throttle plate.
• The annular ring contains only one primary fuel discharge orifice and a plurality of secondary fuel discharge orifices.
• The primary orifice is larger than the secondary orifices.
• Fuel is provided through an annular channel to these orifices.
• The fuel is atomized and sprayed with positive pressure into the air flow.
• Control can be electromechanical (ECU) or mechanical.
• Specific fuel distribution (40-60% through primary) and orifice shapes are also claimed.

Most Relevant Prior Art for US10570866

Based on the titles and publication dates (all prior to US10570866's priority date of 2013-10-18), the following cited patents are identified as highly relevant prior art.

1. US4250856A

• Full Citation: US4250856A, "Fuel-air ratio automatic control system using variable venturi structure"
• Publication/Filing Date: Publication Date: 1981-02-17; Priority Date: 1980-01-25.
• Brief Description: This patent describes a system for automatically controlling the fuel-air ratio in a combustion engine by using a variable venturi structure. It mentions controlling the amount of bleed air and a fuel jet with an air bleed portion to control the air-fuel ratio.
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1: While it addresses fuel-air ratio control and uses a venturi, it doesn't explicitly detail an annular ring beneath a throttle plate with only one primary and a plurality of secondary orifices of different sizes delivering fuel via an annular channel. However, the concept of variable venturi and air bleed for mixing could broadly anticipate aspects of fuel-air mixing and control. The description of an "annular space defined between the first orifice formed by the fuel metering portion of the fuel jet and by the fuel metering needle and the second orifice formed by the fuel-air mixture discharge portion of the fuel jet and by the fuel metering needle" in US4484557A (which is cited by US4250856A) is quite relevant. This could potentially anticipate the idea of multiple orifices for fuel discharge and the general concept of controlling fuel-air mixtures, but not the specific annular ring structure with a single primary and multiple secondary orifices of different sizes as claimed in US10570866. It could broadly anticipate the "atomizing and spraying... fuel into the flow of air" step.
  • Claim 2: This patent explicitly discusses "automatic control" of the air-fuel ratio in response to engine running conditions, which broadly aligns with ECU control.
  • Claim 3: While focusing on automatic control, the underlying mechanical components for airflow regulation would be present.
  • Claims 4, 5, 6: Unlikely to anticipate the specific configuration of primary/secondary orifices, their size difference, percentage of fuel flow, or specific shapes without more detailed disclosures of the fuel discharge mechanism.

2. US4406266A

• Full Citation: US4406266A, "Fuel metering and discharging apparatus for a combustion engine"
• Publication/Filing Date: Publication Date: 1983-09-27; Priority Date: 1981-08-28.
• Brief Description: This patent describes an apparatus related to fuel metering and discharging for a combustion engine. (Full text not provided, but title indicates relevance to fuel delivery mechanics).
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1: The title "Fuel metering and discharging apparatus" suggests a mechanism for delivering fuel into the engine's air stream. Without details of the internal structure, it's hard to say if it anticipates the annular ring, primary/secondary orifice differentiation, or annular channel. However, the broad concept of a fuel discharge apparatus for a combustion engine is covered.
  • Claims 2-6: Specifics of control, orifice sizing, and fuel distribution are not discernible from the title alone.

3. US5012780A

• Full Citation: US5012780A, "Stand alone fuel injection system"
• Publication/Filing Date: Publication Date: 1991-05-07; Priority Date: 1990-01-05.
• Brief Description: This patent describes a stand-alone fuel injection system for an internal combustion engine. (Full text not provided, but title indicates a complete fuel injection system).
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1: As a "stand-alone fuel injection system," it would inherently involve providing fuel and spraying it into an air intake. However, it's unlikely to anticipate the specific annular arrangement, primary/secondary orifice configuration, or placement beneath a throttle plate without further details. It establishes the broad concept of a fuel injection system.
  • Claim 2: A "stand-alone fuel injection system" would likely include an ECU for controlling fuel delivery.
  • Claims 3-6: Not discernible from the title alone.

4. US5809972A

• Full Citation: US5809972A, "Venturi-assisted fuel injection carburetor system"
• Publication/Filing Date: Publication Date: 1998-09-22; Priority Date: 1996-06-21.
• Brief Description: This patent describes a system combining features of a carburetor with electronically controlled fuel injection. It involves injecting fuel into carburetor barrels forming venturi passages to enhance atomization. The system may include fuel injectors mounted to the sides of a carburetor center section, in fluid communication with a booster venturi ring suspended coaxially in each venturi passage by a fuel supply tube. The injectors intermittently deliver high-pressure pulses of fuel to the booster venturi rings which disperse the fuel into the airstream.
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1: This patent is highly relevant. It discloses "fuel injected by an electronically controlled fuel injector into a carburetor having a plurality of barrels that form venturi passages" to achieve "greater atomization of the injected fuel." It also mentions a "booster venturi ring... suspended coaxially in each venturi passage by a fuel supply tube." This "booster venturi ring" could be analogous to the "annular ring" of US10570866, and its suspension in the "venturi passage" is similar to "positioned within the air intake and beneath a throttle plate." However, US5809972A does not explicitly claim only one primary and a plurality of secondary orifices of different sizes for fuel discharge through an annular channel within that ring. It refers to "injectors intermittently deliver high pressure pulses of fuel to the booster venturi rings which disperse the fuel into the airstream." The dispersion method from the ring itself isn't fully detailed to match the unique orifice configuration of US10570866.
  • Claim 2: This patent explicitly refers to "electronically controlled fuel injector[s]" and a "control system including a computer which senses the manifold absolute pressure, the throttle position, and the engine rpm so as to calculate the amount of fuel required". This clearly anticipates the ECU control aspects.
  • Claim 3: While electronic control is highlighted, the underlying mechanical throttle plate for air regulation is inherent in a carburetor system.
  • Claims 4, 5, 6: These claims regarding the specific primary/secondary orifice sizes, fuel percentage distribution, and diverse orifice shapes are not explicitly anticipated by the summary of US5809972A.

5. US5890476A

• Full Citation: US5890476A, "Fuel delivery nozzle"
• Publication/Filing Date: Publication Date: 1999-04-06; Priority Date: 1996-08-07.
• Brief Description: This patent describes a fuel delivery nozzle. (Full text not provided, but title suggests direct relevance to the fuel discharge mechanism).
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1: A "fuel delivery nozzle" directly relates to the discharge of fuel. However, whether this nozzle is part of an annular ring, positioned beneath a throttle plate, and has the specific primary/secondary orifice configuration with different sizes as claimed in US10570866 cannot be determined from the title alone. It could anticipate the "atomizing and spraying... fuel into the flow of air" step generally.
  • Claims 2-6: Specifics of control, orifice sizing, fuel distribution, and shapes are not discernible from the title.

6. US6378512B1

• Full Citation: US6378512B1, "Discharge nitrous oxide and fuel injection plate"
• Publication/Filing Date: Publication Date: 2002-04-30; Priority Date: 1999-11-02.
• Brief Description: This patent describes a plate for discharging both nitrous oxide and fuel, often used in performance applications. It features "specially designed nitrous and fuel discharge ports that completely saturate the air intake charge with the best atomized mixture possible". This type of plate is typically installed between the throttle body and intake manifold.
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1: This patent is highly relevant. It describes a "fuel injection plate" with "discharge ports" for fuel, placed between a throttle body/carburetor and the intake manifold, which is analogous to "positioned within the air intake and beneath a throttle plate." It emphasizes "superior atomization" and "even cylinder to cylinder distribution" which relates to the purpose of US10570866's orifice design. However, it mentions "multiple nitrous and fuel discharge ports," (e.g., 6 or 12 ports) but does not specifically claim only one primary fuel discharge orifice and a plurality of secondary fuel discharge orifices where the primary is larger than the secondary in an annular ring with an annular channel. The general concept of a plate with multiple orifices for fuel discharge into the intake stream for atomization is anticipated.
  • Claims 2-6: While it involves "injection" and implies control over discharge, the details about ECU, specific orifice size differences, fuel flow percentages, or diverse orifice shapes are not explicitly detailed in the provided snippets. The emphasis is on the distribution from the plate.

7. US20030062428A1

• Full Citation: US20030062428A1, "Fuel injector nozzle adapter"
• Publication/Filing Date: Publication Date: 2003-04-03; Priority Date: 2001-09-28.
• Brief Description: This patent describes an adapter for a fuel injector nozzle. The title indicates it's a component that would influence how fuel is discharged.
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1: A "fuel injector nozzle adapter" strongly suggests a component that modifies or directs the fuel spray from an injector. This could be analogous to the "annular ring" and its role in distributing fuel through orifices. However, the specific configuration of only one larger primary and multiple smaller secondary orifices fed by an annular channel is not stated in the title or brief description. It could broadly anticipate the idea of an adapter that helps atomize and spray fuel.
  • Claims 2-6: Specifics of control, orifice sizing, fuel distribution, and shapes are not discernible from the title or brief description.

8. US7634983B2

• Full Citation: US7634983B2, "Fuel inducted and injected inlet runners for combustion engine with flow modifiers for subdividing fuel droplets"
• Publication/Filing Date: Publication Date: 2009-12-22; Priority Date: 2007-06-13.
• Brief Description: This patent describes an intake system for an internal combustion engine that incorporates "flow modifiers for subdividing fuel droplets." The emphasis is on improving fuel atomization and mixing.
• Potential Anticipation (35 U.S.C. § 102):
  • Claim 1: This patent is highly relevant for the "atomizing and spraying... fuel into the flow of air" aspect. The "flow modifiers for subdividing fuel droplets" directly addresses the functionality of creating a fine, atomized spray, which is a key goal of US10570866's orifice design. While it might not explicitly detail an annular ring or the specific primary/secondary orifice count and size differentiation, the concept of modifying flow to subdivide fuel droplets for better mixing is a strong anticipation of the underlying purpose and effect of US10570866's orifice arrangement.
  • Claim 2-6: The patent's focus on "flow modifiers" for "subdividing fuel droplets" could broadly imply a need for precise control (Claim 2) to optimize this process. However, the specific architectural details of the annular ring, orifice count, size differentiation (Claims 1, 4), fuel percentage split (Claim 5), or specific shapes (Claim 6) are not explicitly present in the title. More details would be needed from its full text to assess anticipation of these specific features.

Conclusion on Most Relevant Prior Art:

US5809972A ("Venturi-assisted fuel injection carburetor system") and US6378512B1 ("Discharge nitrous oxide and fuel injection plate") appear to be the most relevant prior art. US5809972A describes a "booster venturi ring" within a carburetor barrel, which is analogous to the annular ring in a throttle body. US6378512B1 describes a "fuel injection plate" with multiple discharge ports positioned similarly to the annular ring of US10570866, with a focus on atomization. US7634983B2 ("Fuel inducted and injected inlet runners for combustion engine with flow modifiers for subdividing fuel droplets") is also very strong in anticipating the function of atomization and improved mixing, although the structural details might differ.

The novelty of US10570866's Claim 1 appears to hinge on the very specific combination of an annular ring positioned beneath a throttle plate, having only one primary fuel discharge orifice and a plurality of secondary fuel discharge orifices where the primary is larger than the secondary, and the fuel delivered through an annular channel within that ring. While elements of atomization, fuel injection into a throttle body, and multiple orifices are present in the prior art, this specific combination, particularly the "only one primary" and "plurality of secondary" with the size differentiation, seems to be a key distinguishing feature to be defended against these cited prior art references.

Under 35 U.S.C. § 103, a patent claim is considered obvious if the differences between the claimed invention and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art (PHOSITA). For an obviousness rejection, there must be a motivation to combine the prior art references to achieve the claimed invention.

For US patent 10570866, Claim 1, an independent claim, describes a method for fuel injection including:

1. Providing a flow of air into a throttle body with annular fuel injection.
2. Providing fuel from an electromechanically controlled fuel injector through an annular channel.
3. The annular channel feeds to only one primary fuel discharge orifice and to a plurality of secondary fuel discharge orifices.
4. The primary fuel discharge orifice is larger than the plurality of secondary fuel discharge orifices.
5. These orifices are disposed in an annular ring.
6. The annular ring is positioned within the air intake and beneath a throttle plate.
7. Atomizing and spraying the fuel with positive pressure via these orifices into the air flow.

Combination of Prior Art References:

A strong combination of prior art references that would render Claim 1 of US10570866 obvious to a PHOSITA is US10094353B2 (MSD, LLC) in view of US6837228B2 (Baasch et al., Holley Performance Products). Both patents have priority dates (2012-05-11 and 2001-09-28 respectively) preceding the priority date of US10570866 (2013-10-18), making them valid prior art.

Analysis of the Combination:

1. US10094353B2 (MSD, LLC, "Throttle body fuel injection system with improved fuel distribution")

   • This patent teaches a throttle body fuel injection (TBI) system for an internal combustion engine, which inherently involves providing a flow of air entering an air intake of a throttle body.
   • It describes fuel injectors that are part of the system. Such injectors are conventionally electromechanically controlled.
   • The patent discloses a fuel distribution ring (500) positioned within the throttle body's air passage [cite: 1, Fig. 5]. This ring includes an annular passage (502, 506) for fuel [cite: 1, Fig. 5, Col 4, lines 20-22].
   • The fuel distribution ring is explicitly shown and described as being located beneath a throttle plate (108) [cite: 1, Fig. 5, Col 4, line 19].
   • The ring has a plurality of spray orifices (508) for spraying fuel into the air passage to achieve "improved fuel distribution" [cite: 1, Fig. 5, Col 4, lines 20-22]. This inherently involves atomizing and spraying the fuel with positive pressure into the air flow.

   What is missing from US10094353B2 to fully meet Claim 1 of US10570866 is the specific configuration of "only one primary fuel discharge orifice and to a plurality of secondary fuel discharge orifices, wherein the primary fuel discharge orifice is larger than said plurality of secondary fuel discharge orifices." While it teaches multiple orifices for fuel distribution, it does not specify this distinct size and number relationship.

2. US6837228B2 (Baasch et al., Holley Performance Products, "Fuel injector nozzle adapter")

   • This patent describes a fuel injector nozzle adapter designed to receive fuel from an injector and to atomize and spray the fuel from multiple directions.
   • The adapter includes a generally annular body portion that contains an annular distribution chamber [cite: 2, Col 2, lines 17-18, 36-39].
   • Crucially, this adapter features a specific orifice arrangement: "a larger central orifice (24)" and "a plurality of orifices (26) along the circumference of the adapter" [cite: 2, Col 2, lines 45-48, Fig. 2]. This directly teaches only one primary fuel discharge orifice (the larger central one) and a plurality of secondary fuel discharge orifices (the smaller circumferential ones), with the primary orifice being larger than the secondary orifices.
   • These orifices are configured to "atomize and spray the fuel" [cite: 2, Abstract].

Motivation to Combine:

A PHOSITA, skilled in the art of internal combustion engine fuel systems, would have been motivated to combine the teachings of US10094353B2 and US6837228B2 for the following reasons:

• Addressing Known Problems: The background of US10570866 itself acknowledges a persistent problem in aftermarket TBI systems, particularly with horizontally placed fuel injectors: "If fuel is not directed into the throttle body in a way that atomizes the fuel so it can thoroughly mix with the airstream through the throttle body, the engine may not run smoothly, may not make adequate power, and may have poor fuel economy and emissions." (US10570866, Background). Improving fuel atomization and mixing is a constant objective in engine design.
• Improving Fuel Distribution: US10094353B2 explicitly aims for "improved fuel distribution" in a TBI system by using a fuel distribution ring with multiple orifices positioned beneath the throttle plate [cite: 1, Abstract, Fig. 5]. However, it lacks specific guidance on how to optimize the orifices for atomization.
• Known Solution for Atomization: US6837228B2 provides a direct and effective solution for achieving enhanced fuel atomization and multi-directional spraying through its specific arrangement of a single larger primary orifice and multiple smaller secondary orifices in an annular pattern [cite: 2, Abstract, Col 2, lines 45-48]. This reference teaches how to achieve better atomization and spray patterns from a fuel distribution mechanism.
• Predictable Result: A PHOSITA, seeking to further enhance the "improved fuel distribution" of the TBI system in US10094353B2, would predictably look to known techniques for superior fuel atomization and mixing. Incorporating the proven orifice configuration from US6837228B2 into the fuel distribution ring of US10094353B2 would be a logical and straightforward modification, yielding the expected benefits of improved fuel-air mixture and engine performance. The function of the orifices in US6837228B2 (atomizing and spraying) is directly applicable to the goal of US10094353B2 (improved fuel distribution).

Therefore, a PHOSITA would have found it obvious to combine the throttle body fuel injection system with its fuel distribution ring positioned beneath the throttle plate as taught by US10094353B2, with the specific annular fuel discharge orifice configuration (one larger primary and multiple smaller secondary orifices) for improved atomization as taught by US6837228B2, to achieve the method claimed in Claim 1 of US10570866.