Service on your Prins CNG DUAL-FUEL HD system

The CNG tanks are mounted with a frame on the truck. The CNG is stored under high pressure in the tanks.

The CNG filling valve is mounted near the CNG-tanks on a tank coupling block (5). In most countries NGV-1 or NGV-2 connections are used. Depending on your configuration, one or both filling valves may be fitted. The filling valve is equipped with a sealing cap, which must be removed prior to refueling. A manual valve is mounted on each CNG tank, which must be open to fill the tanks. 

Every CNG tank is equipped with a tank valve. This tank valve can be manually operated or manually operated in combination with a solenoid valve and has various safety devices.

Tank valve with solenoid valve :

During the switch-over procedure and dual fuel operation, the solenoid valves are powered by the ECU (through the tank valve relay). When the engine is operating in diesel-only mode, the solenoid valves are closed. When the solenoid valves are not powered, they act like a check valve. Flow is possible in one direction, blocked in the other direction. This enables the filling of the tanks, even if the solenoid valves are not powered. The tank valves also have a built-in manual valve. Contrary to the solenoid valves, the manual valves block the flow in both directions. Therefor it is not possible to fill the tanks when the manual valves are in closed position.

The manometer is installed in the tank coupling block. The manometer measures the pressure in the high pressure line to the engine and indicates the tank pressure.

A tank coupling block is installed near the CNG tanks. The filler valves NGV-1, NGV-2 and also the manometer can be mounted on this component.  

An additional manual shut-off valve can be installed in the gas supply line between the tanks and the high-pressure filter. With this valve the engine system can be isolated from the CNG tanks for service purposes or during filling off the tanks. The valve is located behind the cab. 

The high-pressure coalescent filter is installed under the cab upstream of the pressure regulator. It filters solid contamination and separates oil and moisture from the gas. Liquids can be drained from the filter after the system has been depressurized.

The pressure regulator is installed under the cab. The regulator reduces the high tank pressure to a stable system working pressure. The regulator has a built-in solenoid valve and built-in pressure sensor. The signal from the pressure sensor is used to display tank content on the fuel selection switch.

The Filter Injector Unit (FIU) is installed downstream of the regulator and combines the low-pressure filter and the injector housing. The low-pressure filter filters the low-pressure gas before it enters the injectors. The injectors meter the correct flow of gas to the engine. A pressure-temperature sensor measures the pressure and temperature of the gas which is needed for the Dual-Fuel system.

The Filter Injector Unit includes a pressure-temperature sensor. The sensor measures the pressure and the temperature of the gas to the injectors.

The fuel selector switch is located on the dashboard or on the center console. With the switch you operate the Dual-Fuel system.

The fuse is in an available place in the engine compartment. The fuse protects the electronic circuit from overloading.

The fuel selection switch is located on the dashboard. With the switch you operate the Dual-Fuel system.

 

The AFC is located inside the truck cabin. The AFC is the center of the installation and processes all incoming signals and drives the different actuators.

The DC/DC converter is located in the truck’s fuse/relay box in the truck dashboard. The converter is designed to allow the use of the 12-volt Diesel/CNG system in a 24-volt vehicle.

Starting

The engine always starts with diesel. Depending on the engine temperature and after the system check, the Dual-Fuel system will automatically switch over to the blend mode.

Switching from Diesel to Dual-Fuel and reverse

While driving, you can switch between both options by pressing the fuel selector switch.

The fuel selector switch
The fuel selector switch has two selection modes:

1. 100% diesel mode:       System LED extinguished (Prins logo)
2. Dual-Fuel mode:           System LED illuminated (Prins logo)

The light intensity of the fuel level indication LEDs varies, depending on the amount of daylight.

Fuel level indication
An indication of the fuel level is shown by four or five LEDs. If the red LED is illuminated (low level), the final amount of CNG is being used. This means that the tank is not yet completely empty but that there is still some CNG remaining, depending on the size and shape of the tank installed. Because of the measuring principle of the system measuring the fuel level, this measurement cannot be any more accurate. It is only an indication of the fuel tank contents. Experience will show how much further you can drive in Dual-Fuel mode if the red LED is illuminated.

Diagnosis
A system LED and buzzer are integrated into the switch for diagnostic purposes. The following error messages may occur:

1.         Not critical system error: the diagnose/system check LED flashes.

            Diagnosis:     An error has occurred in the Dual-Fuel system. It is still safe to drive in blend-mode, even from an environmental point of view.
The driving comfort may be reduced.

            Action:          Consult your Prins dealer.

2.         Critical system error: System automatically switches back to 100% diesel-model, the beeper will be activated, and the diagnose/system check LED is illuminated constantly.

            Diagnosis:     An error has occurred in the Dual-Fuel system. It is not safe to drive Dual-Fuel mode. 
Therefore, the system will automatically switch off.

            Action:           Switch off buzzer by pressing the fuel selector switch. 
Consult your Prins dealer.

Filling the CNG tanks must be done as follows:

• Turn off the engine!
• Remove filler cap from filler opening and clean it.
• Click fuel pistol on the filler.
• Press CNG pump button. When the pump stops after a while, the maximum tank pressure is reached. Stop refueling by releasing the button.
• Now remove the fuel pistol.
• Put the filler cap in place to prevent dirt, water, sand and dust from entering the filler opening and therefore the entire system.

Attention: smoking and open flames are prohibited while filling the CNG tank. Also, your cell phone must be shut off.

Disassembly of parts/system

Do not attempt under any circumstances to disconnect or disassemble Dual-Fuel system components. The system contains high pressurized gas. You run the risk of serious burns when doing this. Only have an approved Prins dealer remove or repair the system.

Gas leakage

If you suspect there is a gas leakage, switch off the Dual-Fuel system and if present also close the manual tank valves and contact an approved Prins dealer immediately.

Fire

In the case of a fire, leave the truck and take distance. The CNG tanks are equipped with safety valves that allows the CNG to escape from the tanks in case of abnormal pressures inside these tanks. Thanks to these devices it is impossible for the tanks to explode. Always inform the emergency services that you have a CNG Dual-Fuel system in the truck.

When you drive on Dual-Fuel, maintaining your truck is even more important than using 100% diesel. Since the specifications of gas differ from those of diesel, minor engine problems which won't disturb the driving comfort while using diesel may cause major problems while using Dual-Fuel. Follow the below mentioned maintenance instructions and tips to use your CNG Dual-Fuel system without any problem.

• Proof of maintenance according to the guidelines of the importer is obligatory (completely filled in of the maintenance booklet).

• Maintenance must be carried out by the importer authorized dealer.

• Adjustments and repairs on your Prins Dual-Fuel system should only be carried out by a Prins (or Prins importer) authorized dealer.
   

Registration of maintenance and service of the Prins CNG Dual-Fuel HD system / download version. 

If your truck won't run on Dual-Fuel, follow this checklist:

• Is there enough gas in the tank. Is the tank pressure at least 20 bar?

• Check for defective fuse in the Dual-Fuel system.

Never use a stronger fuse than indicated on the fuse wire. This may cause damage to the system.

If you cannot solve the problem yourself, please contact your Prins dealer or importer in your country. Do not carry out any repairs or readjustments yourself, but have this done by an authorized Prins Dealer, Otherwise, the warranty on your Prins Dual-Fuel system will no longer be valid.

In case it is required to completely switch off the Prins Diual-Fuel system follow the procedure as written below.

• Remove the fuses from the Prins Dual-Fuel system.

• Remove the CAN-bus cable between the original CAN wires and the Prins AFC. 

• Remove the cable between the original wiring loom. Reconnect the original wiring loom with the RPM sensor.

• Remove the Prins wiring harness of the engine’s boost sensor. Put back the original wiring harness of the truck.

In the case of damage repairs to a vehicle with CNG tanks and the truck is placed in a spray/dry booth with a drying temperature higher than 60°C, the system pressure may not be higher than 50 bar.

When a vehicle with a CNG Dual-Fuel system is dismantled, be careful with the CNG tanks, including pipes, due to possible remaining pressure in these parts. 

14.1 Prins warrants that the Products it supplies are manufactured from sound materials and are of sound workmanship. Should defects nonetheless occur in the Products supplied by Prins as a result of manufacturing defects and/or defects in the material, Prins will, after examining the defects in accordance with Article 14.3, repair the said defects, or cause them to be repaired, within the specified term, or provide the components required for repair, or cause them to be provided, replace the Products in full or in part, or reimburse at most the invoice value of the Products, all this at its sole discretion. This warranty shall apply during twenty four (24) months following delivery.

14.2 Should the Product supplied comprise a complete CNG system, this must have been built in by Prins or by a dealer approved by Prins in accordance with the standard instructions and the statutory requirements; if the system will be registered online (warranty portal) within thirty (30) days of delivery, the warranty period referred to in Article 14.1 shall be thirty six (36) months, subject to written deviations. If no online registration (warranty portal) will be examined, the guaranty term of twenty-four twenty four (24) months will start on the delivery date.

14.3 At the request of Prins, the Purchaser shall allow an expert appointed by Prins to examine the defective Product, failing which the right to warranty shall lapse. The decision of the expert shall be binding for both parties. The costs of such expert appraisal shall be borne by Prins if the Purchaser has made a claim under the warranty; they shall otherwise be at the expense of the Purchaser.

14.4 Any claims under this warranty shall be reported to Prins by registered letter within eight (8) days of their occurring. Should the complaint not be submitted within that period, any claim vis-à-vis Prins shall lapse. Any legal proceedings instituted in respect thereof shall be brought before the court within thirteen (13) months of the submission of the timely complaint on pain of their lapsing.

14.5 Should the Purchaser request Prins to repair the Products at the Purchaser’s premises, Prins shall be authorized to invoice the Purchaser for the costs incurred, including travel expenses, accommodation and meals.

14.6 Defects resulting in whole or in part from the following shall not in any case be covered by the warranty:

(a) failure to comply with the directions for use, operating instructions etc. or use other than the intended normal use;

(b) normal wear and tear;

(c) alterations to the information on the warranty card;

(d) alterations to information on the stickers provided by Prins in accordance with its legal requirements;

(e) assembly/installation, repairs or adjustment by third parties, or in any case by a dealer or purchaser not recognized by Prins without Prins’s prior written consent;

(f) the application of any government regulation on the nature or quality of materials used;

(g) materials provided by the Purchaser to Prins to process or execute an order, unless explicitly or otherwise agreed;

(h) materials and/or goods used in consultation with the Purchaser;

(i) advice given by Prins, unless explicitly agreed otherwise;

(j) the processing of Products by the Purchaser, unless Prins explicitly states a specific manner of processing in writing in its documentation brochures etc. or has permitted such without any reservation in writing;

(k) external influences, installation mistakes;

(l) incorrect fuel or fuel of inferior quality;

(m) the use of an additive not approved in writing by Prins;

(n) demonstrable failure to comply with the maintenance schedule prescribed by the car manufacturer, importer and/or Prins.

14.7 Prins shall not be held to any warranty, nor shall it be liable to pay any compensation whatsoever with regard to the Contract should the Purchaser fail to comply with any obligation arising for it from the Contract concluded with Prins or from a related contract, or fail to do so properly or on time.

14.8 Any claim under this Article shall expire should the Purchaser carry out repairs, disassembly or other actions affecting the Products, or should it cause such repairs, disassembly or other actions to be carried out, without Prins’s prior written consent.

14.9 Should Prins replace any components or Products in fulfilment of a warranty obligation, such Products or components shall become its property. Prins shall be authorized to charge transport costs for these Products or components unless Prins has given instructions for the transport.

14.10 Without prejudice to the provisions of Article 15, Prins shall in no case be bound by any other obligation, for example to pay compensation.

Liability

15.11 Prins shall not be liable for any costs, damage or the like that may arise as a direct or indirect result of:

(a) force majeure, as set forth in these conditions;

(b) acts or omissions by the Purchaser, its employees, or other persons who have been put to work by the Purchaser or on its behalf;

(c) the applicability of one of the circumstances specified in Article 14.6.

15.12 Prins shall only be liable to the extent of its insurance cover for any damage (or personal damage) to Products or property belonging to the Purchaser and/or third parties if such has occurred through any intentional act or omission or gross negligence on the part of Prins or of those who have been put to work by Prins, with the amount insured by Prins being the maximum. Should it turn out, for whatever reason, that no insurance cover exists with respect to a given case, Prins’s liability shall be limited to the invoice value, exclusive of VAT.

15.13 Prins shall in no case be liable for any collateral damage suffered by the Purchaser or a third party, including consequential damage, immaterial damage, loss of profits or environmental damage.

15.14 The Purchaser indemnifies Prins against all claims by third parties in respect of deliveries of Products.