Sector: LPG

Zenit Pro Diesel - dieselgas the Polish way

Dual-fuel autogas systems, feeding certain portions of LPG into Diesel engines still running on their original „juice”, are becoming more and more popular. We interviewed Piotr Grabowski, a technical issues manager of Auto-Gaz Centrum, to talk about the company's ZENIT PRO DIESEL product.
ZENIT PRO DIESEL on a Scania truck© Auto-Gaz CentrumA Scania semi-truck with a ZENIT PRO DIESEL system Tell us something about the network of installers fitting your dieselgas system. Is fitting at the customer's facility an option?

Piotr Grabowski: The network of ZENIT PRO DIESEL is growing. Doing the conversion at a customer's headquarters is an installer's choice, but I suppose this option will become more popular over time as it is very convenient for customers. Installers will become mobile workshops, travelling with all the necessary equipment and tools.

Please note that converting a heavy-duty truck to partially run on autogas is no easy task. Fitting the LPG tank, generally under the vehicle's floor due to space limitations, is particularly time-consuming. Mounting an autogas tank usually means replacing one of the diesel tanks.

When you add new installers to your network, do you take truck maintenance stations into consideration? That would be optimal from the truck fleet operators' point of view – having vehicles converted and maintained at the same time and place.

Yes, in fact there are a couple of companies among our ZENIT PRO DIESEL installers who used to be in the truck maintenance business rather than the autogas business before. They have been working with heavy-duty transport vehicle fleets, so they have first-hand experience in terms of many fleet operators' need to cut down their fuel bills. Also, they know Diesel engines inside out, which is crucial when it comes to converting them to run on two fuels at the same time. They are familiar will all the nuances, including truck driving techniques, driver habits and failures typical of given truck models. With this kind of knowledge, we are sure installers can do the job right, including adjusting the LPG system precisely to get as much economically as possible.

Installers' training for the ZENIT PRO DIESEL© Auto-Gaz CentrumA technical training for the ZENIT PRO DIESEL

How would you assess installers' skills in general and what do you, as a company, do to improve them?

Once the ZENIT PRO DIESEL was launched, we held a series of technical trainings to get installers accustomed with its features and the configuration software. The first training attracted installers both experienced with dieselgas systems and new to the technology. Incidentally, we gathered some feedback concerning other dieselgas solutions available today, as well as suggestions and expectations installers have. We are proud to say the ZENIT PRO DIESEL is a technologically advanced product when compared to other systems of this kind.

Choosing to fit the ZENIT PRO DIESEL, installers get an efficient and reliable autogas injection system designed especially for use on Diesel engines. Technical trainings are going to be a constant part of Auto-Gaz Centrum's offer. We want to make sure installers are up-to-date and have constant access to technical information and software updates, so that they know how to install and maintain the ZENIT PRO DIESEL properly.

How many vehicles converted with your system are there on the road already and how do they perform in terms of fuel economy?

We are launching a new batch of ZENIT PRO DIESEL systems onto the market at the moment. It comprises 1000 conversion kits we could call Series 3, as they have been updated in terms of both software and hardware. The previous two series allowed us to field-test the technology and draw experience. Feedback concerning voltage converters in the system's ECU's is particularly important. As it turns out, the first ones we used are still 100 per cent alive and kicking, so now we use the latest iteration of the same components.

As for economical performance of the ZENIT PRO DIESEL, it manages to save 25-28 per cent of the fuel cost on average. Minor differences result from driving style and a high ratio of medium-duty vans, covering relatively short distances. Diesel consumption in their case is around 11-13 l/100 km. Once converted to partially run on autogas, they save 20 per cent at least. Nominally, their dual-fuel economy is approx. 7,5-8,5 l/100 km of diesel and 3-4,5 l/100 km of LPG.

Fuel economy figures for various types of diesel-powered vehicles before and after conversion to LPG

Model/engine capacity/year/fuel system
diesel [l/100 km]diesel + LPG [l/100 km]
Toyota Hilux/2,5 l/2004/common rail

urban - 13

highway - 10

 10 + 3

7 + 3

Mercedes Sprinter/2,0 l/2002/common rail

urban - 11

highway - 10

 6,5 + 3

DAF (local distribution)

5034 + 14
Renault Magnum/430 KM/2001/Mack3423 + 10
Scania R460, 2008, HPI3524 + 10
Solaris Urbino 1236

28 + 8,2 - summer

30 + 8 - winter

What does your dieselgas system demand in terms of maintenance?

Autogas systems used for converting heavy-duty Diesel engines operate under much more difficult and demanding conditions. For this reason we put more pressure on regular maintenance and we recommend that the ZENIT PRO DIESEL be maintained every 20 thousand km. Maintenance is similar to that of regular autogas systems – gaseous and liquid state LPG filters are replaced. As for reducers, we estimate their longevity at approx. 100 thousand km and similarly for Hana injectors we use.

A ZENIT PRO DIESEL conversion kit© Auto-Gaz CentrumA ZENIT PRO DIESEL conversion kit

And how about conversion kits? Are they precisely composed or is there some sort of liberty?

The conversion kit is precisely completed using well-proven components. All the elements required in a sequential LPG injection system are there and we only choose parts known and renowned for their reliability.

We recommend Tomasetto reducers (Alaska as standard) and Hana injectors. And obviously each kit includes a ZENIT PRO DIESEL ECU, complete with wiring harness, a fuel type switch and an MAP sensor. All these components are crucial to the system's reliability and performance.

The ZENIT PRO DIESEL is still new, but is there a successor already in the pipeline?

The ZENIT PRO DIESEL leaves much room for further improvements and updates, technologically speaking. Back at the early stages of its conception, we took into consideration a number of modifications that it can undergo should need arise. It is going to be a while before we have to start thinking of this system's successor.

Still, we have quite a bit up our sleeve. Next up is a version capable of converting Euro 6-compliant vehicles and we expect that once such vehicles become more common, the ZENIT PRO DIESEL will be regarded as a very efficient tool for converting them to run on diesel and LPG.

A Renault Master with a ZENIT PRO DIESEL system© Auto-Gaz CentrumA Renault Master with a ZENIT PRO DIESEL system

The ZENIT PRO DIESEL is now sold in kits containing two autogas injectors and the recommended way to inject LPG is into the airflow before the turbocharger. This is the most flexible way to do this. Using proper diesel-feed emulation (limiting the diesel dose) is a warranty of achieving satisfactory economical effects.

The current iteration of the system allows support of digital input signals and induction sensors. This means the ZENIT PRO DIESEL can be used on most vehicles available today. In the future the system will support OBD. Furthermore, we aim to enhance precise LPG dosage with additional dose corrections and add a simple calibration tool based on a modified algorithm.

Emission standards are becoming stricter and stricter. Is there a risk that dieselgas systems may soon be out of business? Or maybe quite the opposite – will such systems make it easier to comply with the standards?

Dieselgas systems are beyond doubt and eco-firnedly solution, but require precise calibration. In the future, not only will achieving obligatory emission levels require calibrating the LPG system properly, but also modifying the vehicle's original diesel fuel system. Dual-fuel mixtures ignite and burn differently than homogenous ones. Using CNG on a broader scale would be of help as it allows to achieve more efficiency than mixing diesel with LPG, but in the current state of CNG refueling infrastructure in Poland this hardly makes any sense.

Thank you.


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Piotr Złoty
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