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The Scooter Parts Registry

EPA engine family

Engine family PHSNX.454USV

If this code is printed on your emission label, this is your machine's federal record: sold under Hisun Motors Corp., U.S.A., with an engine built by Chongqing Huansong, certified as ATVs and UTVs and side-by-sides.

Displacement
—
Model years
2023
Models certified
17
Certificates
1

What this record says

Engine built by
Chongqing Huansong
Vehicle category
ATVB & UTV - EPA only
Certificate numbers
PHSNX.454USV-009

What the number itself says

Reading PHSNX.454USV left to right: P is the model-year letter for 2023, HSN is the three-character code the EPA assigned to Hisun Motors Corp., U.S.A. as certificate holder, X marks an off-road certification, .454 is the displacement in litres, so 454cc and USV is Hisun Motors Corp., U.S.A.'s own sequence for that year. Nothing in the number names the factory — that comes from the certificate itself.

The engine, as described on the certificate

The test vehicle Hisun Motors Corp., U.S.A. submitted for this family (model HS450UTV) carried engine code HS183MZ. In the Chinese engine-model convention that reads as one cylinder with a nominal 83 mm bore, MZ series.

The certificate describes a four-stroke, single-cylinder engine with 2 valves per cylinder fed by sequential multi-port fuel injection, with an oxygen sensor for closed-loop fuelling, run by an engine control module (ECM). There is a catalytic converter in the exhaust, recorded as "Three Way Catalyst (TWC), single-bed, closed-loop warm up".

Rated power on the record is 17.2 kW (about 23 hp) at 5,500 rpm, driving through a CVT (belt and variator).

Engine code on test vehicle
HS183MZ
Nominal bore (from the code)
83 mm
Cylinders / valves
1 · 2 per cylinder
Cycle
four-stroke
Fuel delivery
sequential multi-port fuel injection
Oxygen sensor
yes (closed loop)
Engine control
ECM
Catalytic converter
Three Way Catalyst (TWC), single-bed, closed-loop warm up
Rated power
17.2 kW (≈23 hp)
Rated speed
5,500 rpm
Transmission
CVT (belt and variator)
Sales area
50S+49S
Vehicle built by
Chongqing Huansong Science and Technology Industrial Co., Ltd.; Vietnam New Century Industrial Company Limited
Test vehicle model
HS450UTV

Filing history and where it was sold

Hisun Motors Corp., U.S.A. filed one certificate under this family, for model year 2023, sold as both a 50-state and a 49-state version.

The vehicle itself is recorded as built by Chongqing Huansong Science and Technology Industrial Co., Ltd. and Vietnam New Century Industrial Company Limited in China and Vietnam, while the engine came from Chongqing Huansong. Chassis parts and engine parts therefore have different origins.

Certified emission levels: CO 3.3, HC+NOx 0.6 g/km.

Other records carrying the same engine code

Hisun Motors Corp., U.S.A. certified an engine with this code under 15 other family numbers — the same engine filed again in another year, or in an off-road and a street version:

  • KHSNX.454ATT (2019)
  • KHSNX.454UTV (2019)
  • LHSNX.454ATT (2020)
  • LHSNX.454UTV (2020)
  • MHSNX.454ATT (2021)
  • MHSNX.454UTV (2021)
  • NHSNX.454ASV (2022)
  • NHSNX.454USV (2022)
  • PHSNX.454ASV (2023)
  • RHSNX.454ASV (2024)
  • RHSNX.454USV (2024)
  • SHSNX.454ASV (2025)
  • SHSNX.454USV (2025)
  • THSNX.454ASV (2026)
  • THSNX.454USV (2026)

A shared code from the same factory is a strong search lead. From a different factory it is as often a naming coincidence. Either way it narrows the search; it does not settle it — measure before you buy.

Models certified under PHSNX.454USV

Every model designation the importer listed on this certificate. If your machine's model name appears here, this is the right record — even if the name on the bodywork is slightly different.

Axis 450 · Bad Boy 450 · Big Boy 450 · Big Dirty 450 · Coleman UT400 · Coleman UT450 · HS400UTV-2 · HS400UTV-3 · HS400UTV-4 · HS400UTV-5 · HS450UTV · Outfitter 400 · Outfitter 450 · Sector 450 · UT400-RT · Vector 400 · Vector 450

Other American badges on engines from the same factory

Related in the registry

Source. US EPA annual certification data — EPA Certified Highway Motorcycle Test Results, MY2006-present; EPA Certified Off-Road Motorcycle / ATV / UTV / Rec Vehicle, MY2006-present. Retrieved 2026-09-07. Full provenance and method.