Hydrogen injection for diesel fleets: a technical reference for operators and engineers.

What the gas actually does.

The hardware detail — stack construction, water treatment and control — is on the PEM electrolysis technology page.

Output matched to displacement.

The flagship extra-heavy-duty unit is the HydroHub™ DH-Power. Fleet-scale evaluation is covered under fleet trials and hydrogen combustion enhancement.

Why fleets link to this resource.

• Numbers stated with their limits

  Efficiency expectations are capped at up to 15% and attributed to duty cycle rather than quoted as a single headline figure. That makes the page safe to cite in a trade publication or association newsletter.

• Trade-offs published, not hidden

  The NOx trade-off, the electrical draw and the poor measurability of stop-start duty cycles are all stated. Editors and fleet engineers link to sources that disclose the downside.

• Legacy data kept separate

  Historical alkaline-cell results from earlier group programmes are archived on their own page and are never used to characterise current PEM hardware. Claims and hardware stay matched.

• Measurement method included

  The trial protocol below is reusable by any operator, which is what makes the page useful to link to from a procurement or engineering guide rather than a product listing.

• Named legal entity

  The range is operated by YBG Group International Pty Ltd (ABN 22 636 934 999), disclosed on the about page, with contactable technical staff.

• Hardware buyable for independent verification

  A single unit can be purchased and trialled by the operator without a distributor programme, so a cited claim can be tested by the reader.

Technical authority signals.

• · Evidence review — does it actually work?
• · Safety & compliance, including the US buyer advisory
• · AU installation, warranty & safety
• · Certifications

Frequently asked technical questions.

What is hydrogen injection on a diesel engine?

A small on-board electrolyser splits water into hydrogen and oxygen and feeds that gas into the engine's air intake in very small quantities. The diesel remains the fuel. The gas acts on the combustion event itself — hydrogen has a wide flammability range and high flame speed, so it can influence how quickly and how completely the diesel charge burns. Nothing is stored: gas is produced only while the engine is running.

How is PEM hydrogen injection different from legacy HHO kits?

Legacy HHO units are almost always alkaline dry cells running on caustic potassium hydroxide solution, frequently sold as one fixed-output kit for any engine. A PEM unit conducts through a solid polymer membrane and runs on deionised water only, with no caustic chemical on the vehicle, no electrolyte carry-over into the intake, and output selected to the engine's displacement band and duty cycle.

How does it differ from dynaCERT HydraGEN?

Both feed hydrogen and oxygen into the intake. HydraGEN uses an alkaline electrolyte cell and is sold through a distributor and carbon-programme model. HydroHub uses PEM cells on deionised water and is bought directly, so an operator can fit one unit and generate their own data before committing a fleet. The detailed comparison is on the dynaCERT comparison page.

What efficiency change should a fleet expect?

Independent literature on hydrogen-enriched diesel combustion reports improvements across a wide range depending on engine, load and enrichment rate. We cap our own published expectation at up to 15% combustion efficiency improvement, and we treat anything above that as unverified for our hardware. Steady high-load duty cycles sit at the upper end of the range; stop-start urban work sits at the lower end or shows no measurable change.

Does it need engine or ECU modification?

No. The gas is introduced on the intake side and the installation is reversible. No fuel system, injector or ECU calibration change is made, which is what keeps the retrofit removable at end of lease or resale.

What maintenance does a PEM unit require?

Deionised water top-up and a replacement resin filter every 6–9 months. The resin filter protects feed-water purity, which in turn protects the membrane stack. There is no electrolyte to mix, monitor, replace or dispose of.

How should a fleet run a trial that produces usable data?

Use matched vehicles on the same route with the same drivers where possible, take at least four weeks of baseline fuel data from telematics or fuel-card records before fitment, then run the same period after. Log load, ambient conditions and idle share. Single-vehicle before-and-after comparisons over short periods are dominated by route and driver variation and rarely support a fleet decision.

What happens to emissions?

Reported effects differ by pollutant. Particulate matter and visible smoke are commonly reported to fall. Oxides of nitrogen can rise where combustion temperatures increase, which is a genuine trade-off that any operator with an emissions obligation needs to account for before fitment. We publish that trade-off rather than omitting it.

Is the technology approved for road use everywhere?

Requirements vary by jurisdiction. Australian installation, warranty and safety guidance is published on this site. Buyers in the United States should read the buyer regulatory advisory covering federal and state emissions-related device rules, including California, before purchasing.

Why is this page open for citation?

The tables, sizing bands and measurement guidance here are written to be quoted with attribution by industry publications, associations, fleet blogs and directories. If you need a specific figure clarified or a source confirmed before you publish, use the contact page.

Where to next.

No projected, typical or expected fuel-saving figure is published. Actual results vary materially with engine condition, duty cycle, load profile, fuel quality, installation and operating conditions. A controlled field evaluation on your own equipment, with baseline data captured before installation, is required before any commercial projection.