Toyota Hilux diesel-gas - savings and more

© gazeo.comThere's a million reasons to have your diesels converted to run on LPG

If you decide to convert a petrol-powered car to LPG, you aim primarily for lower fuel bills. The autogas system won't boost your car's engine's performance, most often you will actually lose a couple insignificant PS and Nm. With a diesel-gas vehicle it's an entirely different story – your savings will be proportionally lower, but you're bound to get some extra oomph under your right foot. Or not, as it largely depends on how the system is tuned – it may just maintain the engine's original performance. But one thing is for sure: no power or torque will be lost.

As far as limited savings are concerned, you have to look at the matter from the right perspective. Since diesel blending LPG systems are meant to be used primarily on commercial vehicles, including heavy-duty ones (buses and trucks), but also vans and pick-ups, as in this particular case, the unspent money should always be multiplied by the number of such vehicles in a fleet and usually there are at least a few. Annual mileage is obviously also a factor – the more distance covered, the better. What aces are hiding up the dual-fuel Hilux' sleeve to help it convince fleet managers mixing diesel and autogas is actually a good idea? Let's see, shall we?

There are 15-16 such aces per every 100 km driven. It means the fuel bills drop by 15-16% (at least in Poland, given local fuel prices), which is thanks to replacing 10 l of diesel alone with 6,6 l of diesel and 3,8 l of LPG per 100 km. Given the autogas system costs 4500 zlotys, which equals to approx. 1070 euros or 1285 US dollars (for a pick-up like this one – a system for a truck would be more expensive, primarily because of the cost of an oversized LPG tank), the investment pays back after covering some 64 thousand km, i.e. a year or less. Every 50 thousand km afterwards mean saving 830 euros/1000 dollars for the company budget. Mutiply that by the number of vehicles in your fleet and what you get is some tangible penny still in your pocket.

© gazeo.comThe "LPG corner" includes the ECU and the LPG reducer. If you only saw this, you would be excused to think you're looking at the engine bay of a petrol-powered vehicle

Just to remind you, an autogas system for a diesel vehicle is different from one made for petrol cars – both in terms of components used and mode of operation. First and foremost, the ECU in a diesel blending system only adds a dose of LPG into a reduced portion of diesel oil (usually around a third) instead of displacing it completely. The STAG DIESEL has been designed and configured to apply two fuels simultaneously into the combustion chambers under all conditions except for idle gear. This means such systems work best for vehicles covering large distances using highways – city driving limits their practicality due to frequent stops and traffic jams.

The reducer (AC R01) and LPG injectors (AC W01) are the same as in petrol conversion kits (in this case there is one injector per cylinder, which isn't obvious when it comes to diesel/LPG blending) and there are some extra sensors: one for knock combustion and one for exhaust gas temperature. They monitor the combustion process and shut down the LPG system if inappropriate air-fuel mixture proportions are detected to protect the engine. Should the autogas system fail, the engine runs on diesel only as usual.

© gazeo.comLPG breathes some life into a diesel. Lots of it

The ultimate argument to convince the unconvinced of diesel-gas systems' advantages is the aforementioned extra performance you may get. While converted petrol-burners displace all the original fuel with the alternative one, yielding greater savings, diesels with some LPG added offer a boost in power and torque, at the same time being also more economical than before conversion. And on top of it all, as an unexpected bonus, there's the face of the fuel station attendant, who asks "I hope you realise you've just filled up with autogas and diesel, do you?" and hears you answer calmly and confidently "Yeah, I know". That's just priceless.