Lads, its really crazy. Ever since I have discovered the great potential of LNG (CNG) as a fuel, I have asked myself why there is so much diesel electric but there is so little gas-electric.
Oh, you need an economic rationale to get going? Let be give you one that will pull your socks off.
Ready? Not so fast.
Before I hammer you with what I think is going to revolutionize big trucking, let me give you some perspective and also drill down on the issues at hand.
Current trucking thrives on the diesel engine. The diesel engine has been a miracle in reliability and torque. Diesel as a fuel carries great energy density and you can fuel up even the biggest truck in a matter of minutes. And in the case of long distance trucks, this filling gives you way beyond 1000 km (700 miles) range.
It’s no surprise that the diesel engine took the world by a storm. The only environment that is not suited to it is the deep arctic because engines freeze over – but even that has been taken care of.
The diesel engine has only one real problem. And this is a killer.
If we look at fuels in a dispassionate manner, diesel is on the very trashy side of the fractionation column. This means that not only is it a pretty wild cocktail of a whole plethora of hydrocarbons. It also produces very nasty exhaust gasses when it burns and I am not even talking about CO2 here. Two of the nastiest substances coming out of the diesel exhaust are Nitrogen Oxides (NOx) and Fine Particulate Matter (PM). I will concentrate on the PM here but that does not mean that NOx is a thing to be neglected. It’s highly toxic and most developed countries limit its dumping into the atmosphere drastically.
Modern types of diesel also seem to filter fine PM out of the exhaust stream but since VW we know that most of this is a sham. The industry has figured out that single particles get smaller if the temperature and the pressure in the engine is higher. The drawback is that those finer particles are even more toxic than the bigger ones before. Legislation has not yet fully seen through the deception so we inhale this toxic, but unregulated nano-dust in never before experienced quantities.
The diesel engine cannot really be made clean economically. Producing a truly clean diesel would make the engine so darn expensive, our economies would take a dip because of all this extra cost. So we swindle the vehicle industry through by allowing them to break the law repeatedly.
However, no matter what is being done to save the diesel – in the mid- to long-term diesel is doomed and will have to be replaced.
Those who know me will not be surprised top read that I am a lifelong advocate of Natural Gas as a fuel. CNG for smaller vehicles or those on short commutes and LNG for those with more extensive needs. This should solve the problem because LNG as a fuel behaves much like diesel. It’s easy and quick to refuel and one tank filling gets you way beyond 1000km. All this without many of the nasty side effects. Great.
There is – however – still one drawback. Gas engines are not known to provide a lot of torque. The engine feels a bit flimsy at times so trucks running on NG tend to be taken for tours that don’t include lots of steep roads or other forms of hard labor. Plus, it’s hard to put those engines into construction or digging machines as those beasts need lots of torque in order to do what they do.
E-motors on the other side are veritable torque monsters. They crank out huge power pretty much from the first second. Their problem is batteries that are big, expensive and hard to handle. It’s unpractical for most purposes.
But what if someone combined the two?
Strangely the core principle has been in use for decades now in all kinds of heavy diesel applications. They use a diesel engine in order to produce power and electric drives to power the vehicle. There is no direct power transmission between the diesel engine and whatever needs moving. The same could be done with gas and there are applications doing exactly this.
Even simpler, you have an onboard internal power plant that produces electricity on demand using liquid fuels that carry great energy density and provide range. Diesel electric is not exactly a new thing in shipping and many other heavy horsepower applications. Look at those really big mining trucks from Belorussia, the Belaz 75710, the biggest in the world that run on diesel electric. Gas-electric works along the same principles. Just look at one of the biggest warships of the US navy, the USS Zumwalt. It uses a gas turbine in order to produce the electricity for the boat.
If you think that electric drives cannot be powerful I beg you to think again. The biggest US aircraft carriers with more than 100.000 tons deadweight are being propelled to insane speeds (for marine vessel standards) by electric drives. They take their primary energy from nuclear fuel instead of gas but the principle is not very different. Produce electricity in order to propel the vehicle. Same for those monster submarines that can loiter for weeks.
Why should that be different for an 18 wheeler truck? Let’s just imagine that all the wheels of the truck are equipped with electric drives. That makes the truck the ultimate torque monster.
It has been done with gasoline, it is being done with diesel. There is no reason on earth that it would not work just as well with Natural Gas.
This one is for the tinkerers out there. There are LNG fuelled and powered trucks, there are diesel-electric trucks. Combine the two and make it a gas-electric truck. It’s simple for the vehicle engineers.
Take the diesel-electric truck, pull out the diesel engine, the diesel tanks and all the other stuff that’s diesel, attach a standard LNG fuel tank, put in a standard and relatively small gas engine and a vaporizer tube and that should be it. Range should be similar as for the diesel-electric which means 4 digit km per filling. Plus, the truck could be made a plug-in so it can recharge the buffer battery overnight for full electric driving for the first hour every morning. The gas engine would kick in only if the buffer runs down.
This would be an incredibly clean vehicle as not only this is a clean gas engine that does not even cause some of the nastiest components in diesel exhaust streams, it’s also an engine that runs on a very even regime which means that it burns fuel optimally and with a lot less nasty exhaust than a comparable full gas truck.
What’s the problem holding you back folks? The transport world waits for this and if you can demonstrate that it works well, you have a new iPhone as this will sell like crazy.
I am not a mechanical engineer but there are many out there who are. Get up and going. I want to see some of you guys getting rich while the world gets rid of diesel.