Increase the Efficiency

Of Your Diesel Combustion Engines.
(And Realize Real Savings).

The piston stroke of large industrial diesel engines may incorporate as little as 70% of the cylinder volume before the next firing, leaving 30% of the fuel still burning by the time the piston reaches the bottom of the power stroke. The partially burned hydrocarbons are left behind as carbon deposits, clogging the engine, contaminating the oil, and producing pollution and smog.

How D-HAT Hydrogen Infusion Improves Diesel Combustion

Hydrogen is unrivaled in its ability to release more energy than other alternatives. It is the perfect combustion catalyst. When introduced into the diesel engine cylinder, hydrogen safely promotes a faster fuel burn.

Hydrogen makes the diesel fuel and air mixture burn faster, hotter, and earlier in the power stroke, which pushes the piston down harder (increasing torque) so almost all the fuel burns completely before the exhaust valve is opened near the bottom of the stroke. This increases combustion efficiency and leads to less fuel spent on a given amount of work.

The addition of hydrogen also reduces harmful emissions:

  • A more complete burn reduces unburned hydrocarbons, including particulate matter.
  • Increased torque produces more pulling power, allowing more work to be done while using less fuel. 
  • A faster and more efficient combustion process lowers exhaust temperatures for a cooler engine and fewer nitrous oxides (NOx).
Hydrogen on Demand Technologies

Under the Hood of Diesel Hydrogen Assist Technology

Hydrogen on Demand Technologies

The D-HAT generator is a ruggedized and compact enclosure measuring 18”x 13”x 12” with a dry weight 35 lbs. The system consists of recycled and recyclable materials and contains no hazardous materials.

The top half of the D-HAT system houses our proprietary PEM fuel cell system and a water reservoir containing enough distilled water for up to 1,500 miles of road usage (or approximately 50 operating hours).

Hydrogen on Demand Technologies

Enabling Technology

The enabling technology behind D-HAT is a patented Proton Exchange Membrane (PEM) cell that safely produces green hydrogen gas onboard and on-demand through an electrolysis process to improve the combustion characteristics of diesel engines.

The PEM cell produces pure hydrogen gas using only distilled water (with no additives) and electricity from your engine's alternator. It separates the water into hydrogen and oxygen atoms. Only the hydrogen gas is fed through a delivery line and infused through the air-intake manifold, where it becomes part of the ambient airflow, making the combustion process extremely efficient, complete and clean.

The Safety Of Hydrogen On Demand

The D-HAT onboard generator only operates when the engine is running to produce hydrogen on demand from distilled water. The PEM electrolysis process completely separates the hydrogen and oxygen gases; the pure hydrogen gas is immediately directed into the engine’s air intake system and fully consumed. On-demand production eliminates the need for onboard hydrogen storage. The minute amount of hydrogen is never under pressure, eliminating any risk of explosion.

Hydrogen on Demand Technologies

The Onboard Efficiency Of Hydrogen On Demand

Our highly efficient PEM cell produces up to 4 standard liters of nearly 99.9% pure hydrogen per-minute through electrolysis by drawing minimal amperage from your engine’s alternator. The system consumes approximately one gallon of distilled water every 1,500 miles between recommended refills.


Hydrogen on Demand Technologies

About 1 gallon of distilled water every 1,500 miles and approximately 65 amps drawn off the engine’s alternator.


Hydrogen on Demand Technologies

4 standard liters per-minute of approximately 99.9% pure hydrogen that increase the combustion efficiency of your engine to 95% or higher.

D-HAT Product Specifications


Product Specifications

Technology Proton Exchange Membrane (PEM) electrolysis.
Hydrogen gas production @STP 4 standard liters per minute (SLM).
Oxygen gas production @STP 2 standard liters per minute (SLM).
Hydrogen purity Up to 99.9% by volume
Minimum Water Consumption Rate (@ 100% rated output) 1 gallon per 1,500 miles driven or 20 operating hous, whichever comes first.


Physical Specifications

Dimensions 18”x 13”x 12.”
Dry Weight 38 lbs (dry).
Filled Weight 50 lbs. (wet) with full 2.5 gals internal distilled water tank.
Construction Dual ruggedized powder-coated enclosure. Military-grade shock and vibration management design.
Distilled water reservoir capacity 2.5 gallons. Built-in water tank with quick-fill spout, water level indicator and low water level sensors, and water purity sensor with auto system shut down.
Max operating range Up to 3,750 miles or 50 operating hours per tank (whichever comes first).
Operating temperature range -40◦ C to 85◦C (-40◦F to 185◦F). Temperature controlled with integrated heating/cooling for optimal performance in extreme hot/cold weather.


Electrical Specifications

Telemetry IoT enabled controller with cellular connection.
Data Analytics Onboard telematics remotely monitor system functionality, ongoing MPG, and system update programming on a real-time basis for optimal hydrogen production and automatic system protection.
In-cab controls Cab-mounted LCD shows system status and driver interface for monitoring distilled water level and system functions. Has sensors and warning lights to inform the user of its status. Records the number of hours of operation of both the engine and the unit. It is monitored remotely.
Operating voltage range (nominal) 12-24 VDC
Max. power consumption (@12 volts) 65 A Power is pulled from the charging system.
Max power consumption (@24 volts) 32.5 A Power is pulled from the charging station.



Certification Tested to SAE J14555 and MIL-STD – 810F.
Certification UK Electromagnetic Compatibility – ESA T10A-8976-00.
Certification UK Vehicle Authority E-11 VCA 10-R-058976.
Certification California Air Resources Board (CARB) Executive Order D-716.
Warranty Limited 5-year 500,000 miles.


The D-HAT hydrogen on-demand system is an aftermarket device that is safe and easy to install. In most cases from start to finish, it can be installed and fully functional on any semi-tractor or similar size diesel engine in approximately 4-8 hours, minimizing equipment downtime.

The installation process is simple:

  • The D-HAT generator is mounted behind the cab or on the chassis rail.
  • The unit is connected to your charging system for power.
  • The hydrogen line is installed, leading to your air intake system.
  • The system contains a small coolant module mounted to the front of the radiator.
  • The D-HAT generator is wired to the charging system and is controlled via the ignition switch, ensuring the system produces hydrogen only when the diesel engine is running.
  • While each D-HAT system is remotely monitored while in operation, a small LCD display can be mounted in the cab, so you can monitor the system from the cockpit.
Hydrogen on Demand Technologies
Hydrogen on Demand Technologies


The D-HAT system is non-intrusive, infusing a small amount of hydrogen into the air intake system. There are no modifications made or required to the engine, engine sensors, or air-fuel settings. 


D-HAT systems are modular and can be scaled up to increase hydrogen production. For instance, semi-tractors with 9-15 liter engines require a single D-HAT unit. Engines with larger displacement require multiple D-HAT systems. D-HAT units are completely interchangeable from one engine to another of similar displacement.

Hydrogen on Demand Technologies
Hydrogen on Demand Technologies

Maintenance-Free Operations

D-HAT systems are covered by a limited 3-year/300,000 mile/25,000 hour, warranty. The system does not use any electrolytes or additives, making it safe and easy to use, maintain, and refill with commonly available distilled water. Just add one gallon of distilled water every 1,500 miles, and you are good to go year-round in all seasons.

D-HAT will help extend the life of your diesel engines by purging them of carbon deposits, so they run better, cleaner, and longer. They will also require significantly less maintenance because of extended service intervals. We also fully back every D-HAT system with a limited 300,000 mile (or 25,000 operating hours) five-year warranty.

Don’t Just Take Our Word For It

HOD Tech completed joint benchmark testing, along with other industry contemporaries, with the U.S. Department of Energy in November 2019. The DOE quantified D-HAT’s ability to curtail the harmful effects of pollution from diesel engines with the following results:

  • Improvement in fuel efficiency by 9.94%.
  • Reduction in particulate matter emissions (black soot) by 64%.
  • Reduction in nitrous oxide emissions (acid rain) by 77%.
  • Reduction in carbon dioxide emissions (greenhouse gas) by 15%.

Download your copy of the DOE report today and see how D-HAT can help you curtail emissions and save thousands of dollars in annual fuel and maintenance costs.

Hydrogen on Demand Technologies