The diesel engine has proven to be a very successful variant of the Internal Combustion Engine (ICE), an invention that has been around for over 200 years now.
This method of converting the latent energy contained in fuel into useful work has been refined almost beyond recognition from the mere patents and designs of the early 19th century.
Despite this early start, it was the steam engine that fueled the industrial revolution.
It was not until the combustion of fuels moved into the cylinder that the convenience of mobile power became both apparent and readily available.
The rapid adoption of this internalization of combustion was made possible by the opening up of petroleum reserves which provided the easily manageable source of energy for the new engines.
Oil reserves are far from infinite
Concerns about the future availability of oil are not new, nor are concerns about pollution.
Problems facing this proven technology today are increasingly stringent emissions standards and competition from electricity produced from energy sources other than fossil fuels.
These are the two major challenges that have been recognized by the German Society of Agriculture, DLG.
The organization is busy promoting its exhibition in Hanover next spring, during which a wide selection of engine manufacturers will have the opportunity to present their response.
Presenting the fifth “Systems and Components†exhibition, to be held in collaboration with Agritechnica next year, the company states:
“Although combustion engines, especially diesel engines, are widely seen as being on the verge of extinction in the public debate, they are far from over in the off-road sector, where they represent high availability. , reliability and low operating costs.
A double challenge for diesel
Engineers who design future power plants have two main goals which are to increase efficiency while reducing emissions.
They are largely interconnected, as getting the most out of fuel will naturally decrease carbon emissions per unit of work performed, as well as all other pollutants labeled as harmful to the environment.
The problem with electricity
The general assumption is that electricity produced from renewables will replace oil as the main source of energy, but the major problem associated with this plan is that it is difficult to store electricity for future use. .
Josef Horstmann, Krone’s retired development director, said “batteries are not for us” when speaking with Agriland recently. He also noted that the diesels will still be around for at least “20 years”.
The problem is that of energy density; carbon-based fuels are much more efficient at storing energy than batteries, but less at releasing it for useful work.
This was tacitly admitted by John Deere who in 2016 flaunted their idea of ​​a battery-powered tractor with a range of around four hours.
Three years later, the company announces a fully electric and autonomous tractor, this time powered by an external source to which it is connected by an umbilical cable.
A menu of power options
If battery power is still a long way off and arouses little enthusiasm among the main tractor manufacturers, are there alternatives to fossil fuels?
The answer seems to be a categorical yes according to the DLG, which highlights three other technologies currently available, and even already in use.
Methane
Methane, either in the form of natural gas or produced from organic matter, is one of those energy storage systems that is getting a lot of attention.
Case New Holland is already building a methane-only tractor that will go on sale later this year. Ignition is by spark rather than compression, although it is based on a diesel engine block.
If the methane is produced by bio-digesters or recovered from agricultural waste, then it can be referred to as biomethane, which can be considered a carbon neutral solution.
If it comes from natural gas infrastructure, then it will be fossil fuels. Either way, engines still require exhaust after treatment.
Synthetic fuels
Creating carbon-based fuels from regenerative electricity (wind, solar) and carbon dioxide (CO2) already in the air is a rapidly maturing science.
Such fuels can be used as a direct replacement for current fossil liquids.
If produced by solar energy, they closely mimic the management of natural energy through photosynthesis.
Critics note that while this is entirely possible, it still involves inefficient combustion of fuel, wasting a greater proportion of the energy collected, compared to fully electric systems.
Hydrogen
Hydrogen gas is the simplest and lightest molecule in nature. Fortunately, it combines with oxygen to form water and thus releases energy.
The combination of the two elements can occur in a fuel cell, to produce electricity directly, or burnt in an engine.
No carbon emissions are involved in either technique, except for a tiny amount from the consumption of lubricant in the latter.
Burning hydrogen in an engine, rather than processing it in a fuel cell, is once again considered far too inefficient by many, but others believe the opposite.
It should also be noted that most commercial hydrogen is currently produced from petroleum.
Deutz has already produced a prototype hydrogen engine as an alternative to fuel cell technology. It is a variation of its standard six-cylinder unit for agricultural machinery.
The company is also exploring its use in various hybrid configurations, particularly its combination with electric drives.
This ties in with the idea that driving tools by electric motors, rather than a mechanical power take-off (power take-off), will become the preferred option in the future.
Alternative fuels influencing engine design
The DLG concludes its review of the various fuel options by noting that “the diesel engine will remain the engine of choice in the technology mix for the foreseeable future, but it now has competition.”
Although compression ignition may face an uncertain long-term future, the reciprocating internal combustion engine as a mechanism for releasing latent energy in fuels still has a long way to go before it disappears altogether. the scene.
That’s not to say that manufacturers sit idly by while they wait for a big decision to be made. The focus is now on adapting engines to different fuels.
Fuel flexibility is crucial
In addition to increasing power density, “suppliers are paying great attention to the modularity of their engine systems,” according to the DLG.
This means that “components with flexible mounting positions allow different installation options and system integration depending on requirementsâ€.
Agriland To already reported that Kohler is an engine supplier fully engaged in modular engine design and is now entering the consumer tractor market.
AGCO Power also announced that its new factory in Finland will produce a range of engines capable of burning a wide variety of fuels, although no further details have yet been given.
However, sources close to the company suggest that it is looking beyond the alternatives highlighted by the DLG and that it assumes that the composition of diesel fuel will change to include non-fossil-derived ingredients, such as those produced from food waste.
The internal combustion engine has come a long way in the past 200 years.
Given the ingenuity of engineers, coupled with the recognition that electric power still faces the problem of storage, it may still have many years ahead of it.
