US 11,859,525 B2
Apparatus · System Patent
Turbocharger Manifold, System, and Method
The Hlava STM is a mechanical exhaust-side architecture that delivers small-turbocharger transient response and large-turbocharger peak output, while allowing prioritization of a pre-turbo close-coupled catalyst strategy to support catalyst light-off readiness.
The Hlava Sequential Turbocharging Manifold manages exhaust gas delivery between two turbochargers of different frame sizes using a dual inline full-flow bypass valve architecture and an inter-turbo bridge conduit. The system self-regulates on exhaust pressure, temperature, and volume.
Conventional sequential turbocharger plumbing routes exhaust gas through external bypass valves between the cylinder head and the turbine inlets. That configuration occupies the volume immediately downstream of the exhaust ports and physically displaces the catalyst from the close-coupled pre-turbo position.
The Hlava STM integrates the bridge conduit and bypass valve mechanism inside the manifold body. The volume immediately downstream of the exhaust ports is preserved. The catalyst can mount at the cylinder head. The manifold mounts downstream. Catalyst placement is decoupled from turbocharger staging.
The system operates on exhaust energy alone. No external actuators. No electrical power. No 48V bus. No new ASIL software layers required.
Valve actuation is governed by exhaust pressure differentials across the bypass valve seats. Spring-tension thresholds are adjustable to suit specific turbocharger frame pairings and engine displacement targets.
The architecture is turbocharger-agnostic, fuel-agnostic, and engine-configuration-agnostic. Application sectors include automotive passenger and performance, commercial transportation, agriculture, construction, marine, stationary power, and defense.
Two issued U.S. utility patents protect the system through 2040 and 2041. Apparatus and method coverage form a double-layer of protection against design-around attempts.
No electronics, no 48V architecture, no ASIL software expansion. Exhaust energy drives valve actuation.
Small-frame turbocharger delivers instant transient response at low load. Large-frame turbocharger carries peak output at high load.
Geometry preserves the close-coupled pre-turbo catalyst position. Cold-start light-off readiness is supported by hardware, not software.
Any primary and secondary turbocharger frame pairing. Gasoline, diesel, natural gas, hydrogen-compatible ICE. Inline or V configuration.
At low load, exhaust gas concentrates through the primary turbocharger for rapid spool. The bridge conduit primes the secondary turbocharger continuously. As load rises, the bypass valves open progressively and route additional energy to the secondary stage. The transition is continuous from idle to redline.
Pre Hlava STM valve actuation, all exhaust gas is routed to the primary (small-frame) turbocharger. Turbine spool is rapid. Low, stable boost onset arrives near-instantly. The bridge conduit routes all exhaust gas from the primary turbine to the secondary (larger framed) turbocharger inlet, holding it in a primed, low-speed rotation state.
As exhaust mass flow, pressure, and temperature rise with load, the increasing pressure differential across the secondary conduit valve seats progressively opens the dual inline bypass valves, routing additional exhaust energy to the secondary turbocharger. The primary turbocharger receives continuous exhaust gas feed, maintaining prime condition through all transient events, including gear shifts and throttle disengagement.
Positioned inline within the exhaust gas flow path at the Hlava STM inlet, the dual bypass valves govern flow distribution between both turbochargers. Upon opening, the secondary large-frame turbocharger assumes flow priority, receiving the dominant exhaust energy share while the primary operates continuously on overflow. Peak output is carried by the secondary, yet the primary remains active across the entire RPM band, while all exhaust gas travels through the secondary across the entire operating RPM band.
Bench-validated performance on a development engine with a documented turbocharger pairing. The current Technology Readiness Level is 4 to 5. The Series A target advances the system to TRL 6 to 7 across multi-engine, emissions-grade validation.
| Test engine | 3.1L V6 forced induction |
|---|---|
| Primary turbocharger | Garrett GTX2860R Gen2 and Garrett GT2554R. Verification made utilizing various A/R turbine housings. |
| Secondary turbocharger | G35-1050 Reverse Rotation and G30-900 Reverse Rotation. Verification made utilizing various A/R turbine housings. |
| Manifold orientation | Left-hand (right-hand also available) |
| Boost onset | 50% throttle, low engine speed, low vehicle speed |
| Turbo synchronization | Verified sequential synchronization across multiple turbo sizes |
| Technology Readiness Level | TRL 4 to 5 (component validated, relevant environment) |
| Series A TRL target | TRL 6 to 7 (multi-engine, emissions-grade, OEM program candidacy) |
Hlava Technologies holds two issued U.S. utility patents covering the STM. The apparatus patent covers the physical manifold architecture. The method patent covers the control logic independently of the physical apparatus. Both patents share the same August 1, 2020 priority date.
Pre-turbocharger catalyst positioning exploits exhaust temperatures 150 to 250°C higher than post-turbine positions at cold start. The Hlava STM geometry preserves the cylinder-head volume for close-coupled catalyst placement, supporting cold-start NOx and PN compliance across multiple regulatory regimes.
| Standard | Effective Date | STM Compliance Relevance |
|---|---|---|
| Euro 7 | Nov 2026 (LDV new types) Nov 2027 (LDV registrations) |
Tightens cold-start NOx and PN under broadened RDE. Lowers PN to 6×1011 #/km (PN10). Close-coupled pre-turbo geometry is the primary enabling architecture. |
| EPA Tier 4 · LEV IV | Phase-in 2027 to 2033 | Fleet-average NMOG+NOx. Transient response and cold-start light-off are the binding constraints for forced-induction compliance. |
| China 7 | Pre-2030 (draft) | RDE tightening with low-load cycle testing. STM transient response architecture addresses low-load NOx directly. |
| Bharat Stage VII | 2026 to 2027 (target) | Hardware response required. Real-world PEMS data shows NOx 3.7x lab limit in current BS VI vehicles. |
The STM architecture is independent of turbocharger manufacturer, fuel type, and engine configuration. Spring-tension thresholds are adjustable per application. Single-sided and dual-sided embodiments are available.
Any primary and secondary turbocharger frame pairing. Configurable for engine horsepower targets. Agnostic to manufacturer.
Gasoline. Diesel. Natural gas. Hydrogen-compatible internal combustion engines.
Any internal combustion designed to accept forced induction.
Single-valve and dual-valve embodiments are covered by the U.S. Utility patent.
Two physical castings have been produced. Patent marking is cast into every production unit. The Series A capital plan funds supplier-owned OEM-grade dynamometer validation and investment casting manufacturing readiness over a 24 to 30 month window.
Hlava Technologies develops mechanical exhaust-side architecture for forced-induction internal combustion engines. The company is incorporated as a C-Corporation in the State of Delaware, with a principal office in Dover, Delaware. Founder Andrew Hlava is the sole inventor of both U.S. utility patents protecting the STM.