Our Products

We created our own unique fuel additive dosers - they work and are well proven

We have developed automatic additive dosing systems that have a range of options which cover most of the known needs to directly dose fuel tanks on completion of fuelling for small tanks, or in stages during fuelling for large tanks, or directly into fuel flows during fuelling.

Automatic Additive Dosing System 

Towai Technologies' Automatic Additive Dosers (AAD) provide autonomous self contained system which:

  • Can receive fuel data from a wide range of sensors including fuel tank level sensors, CAN networks, electronic flow meters or Keypad Display Units.
  • Accurately dispenses the correct volume of additive into fuel tank(s) or fuel flow over a range of operating and climatic temperature conditions.
  • Supports the full range of known fuel additives with different dosing ratios and a wide range of viscosities.
  • Has two different additive tank capacity options - 5 litres and 20 litres, and can be connected to an external additive tank to increase additive capacity.
  • Is self-contained within its mountings, and has power supply options of either 12 volts or 24 volts dc.
  • Cover the full range of automatic additive dosing requirements.
  • Supports connections to a vehicle onboard computer and to a wireless modem.  

Approximate installed sizes and weights are:

  • AAD 20L    Length: 450 mm   Depth: 440 mm   Height: 440 mm   Weight: 16 kg empty, 35 kg full   Nominal Capacity, 20 L (5.3 gal)  
  • AAD 5L    length: 300 mm   Depth: 260 mm   Height: 260 mm   Weight:  4 kg empty, 9 kg full   Nominal Capacity, 5 L (1.3 gal) 

Click Here for our AAD Product Range Brochure.pdf

Our Range of Options  

Our Automatic Additive Dosers (AADs), which can be supplied with either HDPE Polyethylene or Stainless Steel 316 Marine Grade additive tanks, include automatically dosing:

  • AAD 20L - Vehicle, Vessel & Machine fuel tanks - for dosing on completion of fuelling for additive dosing ratios <3000:1 - 20 litre additive tank.
  • AAD 5L - Vehicle & Machine fuel tanks - for dosing on completion of fuelling for additive dosing ratios >3000:1 - 5 litre additve tank. 
  • BTAD - Bulk Tanks - for dosing depot bulk fuel tanks of up to 130,000L during filling to ensure full additive / fuel mixing - using our 20L additive tank.
  • FFAD - Fuel Flow - for dosing directly into the fuel flow during delivery for either fuel tankers or fuelling depots - using our 20L additive tank.
  • RTAD - Remote Additive Tank - stainless steel enclosure for connecting to a customer supplied additive tank.

Or our KPAD - for keypad entry of the volume of fuel added if no suitable fuel level sensor is fitted.

Note: A customer supplied remote additive tank can be directly connected to our BTAD or our FFAD to increase additive capacity.

Doser Installations 

Some examples of the wide range of vehicle, machinery, vessel, bulk tank and fuel tanker installations are shown below.

Industry Compliance

EMC  (Electromagnetic Compatibility) Compliance

The Electronic Control Board has passed FCC Part 15, Subpart B (class A), ICES-003 (class A), CISPR 22 (class A) and CISPR 25 (class A) EMC compliance testing.

WOSL Approval

Wiri Oil Services Ltd (WOSL), which is collective of the four major New Zealand oil companies, has approved Towai’s Fuel Additive Applicator, including wiring and pipework, for installation on fuel delivery tankers.

Website Downloads Page

Our Doser software and associated documentation can be downloaded from the password protected Downloads page.

If permission to access this page has not already been obtained, then request it by emailing ronlongley@xtra.co.nz.

If approved, Towai will advise you of your password for access to the Downloads page by return email.


Pricing varies dependent upon the options chosen which include:

  • Moulded polyethylene or fabricated stainless steel additive tanks.
  • Cellular modem to enable remote communications with the Doser.
  • Remote switches and operating LEDs for Fuel Tankers.  
  • Number of solenoid valves for fuel tanks - from 1 to 4.
  • Automatic with no driver input, or if no suitable fuel level sensor is fitted then a Keypad Display Unit with minimal driver input.
  • Size of Applicator tank - 5 or 20 litres.
  • Heater fitted - which maintains a minimum set additive temperature for cold climates.
  • Vehicle / machine, vessel, bulk tank or fuel flow options. 

Please contact us for pricing for your application via the Contact page.


Automatic Additive Doser units are warranted against defects in material and workmanship under normal use and service for a period of 12 months from the date of delivery to you, provided that they have been stored, installed and used in accordance with normal industry practices and conditions.

Click Here for our Full Warranty Conditions