The end of the diesel engine? Why oil burners are disappearing in passenger cars but not in utes – yet – Car News
Cast your mind back a decade and a half or so, and a turbo-diesel car was the new black.
A staple in new cars, turbo-diesel technology had finally hit Australia in response to a new Australian standard for diesel fuel (with dramatically reduced sulfur levels) that suddenly caused importers to bend over backwards to grab hold. part of the action.
We had diesel cars before, but they were mostly sold to farmers who filled them from the tractor fuel tank, and they were anything but common.
But in the early years of the new century, we were launching diesel.
This was mostly to the detriment of some gasoline-powered options as well as LPG-powered cars that plunged around the same time.
But these days? Diesel is not such a sexy commodity, and while we are to some extent behind Europe, we still see the diesel fortunes crumble as various factors take hold.
So what is it that kills diesel cars? For starters, it’s a global thing, not just an Australian trend.
Germany, once the star child of diesel passenger cars, saw only half of its new passenger cars sold in 2015 powered by this product. But by 2017, that figure had fallen to just 41%.
Across Europe, diesel-powered passenger cars peaked in 2012 and declined from there. The ban on diesel cars in some major European city centers has certainly played a role.
Volkswagen’s infamous Dieselgate fury didn’t help either, of course, but neither did VW’s decision to ditch the diesel-powered variants of its Golf and Polo models.
The point is that increasingly stringent emissions regulations in Europe are killing the models we once chose from, and it’s impossible to get around.
Even the meteoric rise of the SUV has not allowed the diesel to retain its status as a fashionista.
Although generally larger and heavier vehicles and therefore more suitable for diesel, SUVs in this country have also switched from diesel to gasoline and gasoline-hybrid.
The exception is the thriving double cab market, which is fully diesel, and with the two best-selling models in the country falling into this category, this gives our numbers a bias that Europe is unaware of.
But beyond uses, the affordability of a hybrid drivetrain has also scared diesel, in large part because a hybrid drivetrain can often beat a diesel for fuel economy in stop-start mode and while driving. urban where the majority of Australian cars do most of their work.
Considering that buyers of some new Toyota models tick the hybrid drivetrain option box over 60 percent of the time, you can see the trend.
And there are other factors.
Part of the problem is that trying to run a clean, low emission engine with modern performance while fueling it with diesel is a bit like trying to generate clean, renewable electricity while burning fuel. coal.
The inputs and the results are simply chemically at odds with each other.
Diesel engines have lower carbon dioxide emissions than a gasoline engine doing the same job, but it is the nitrogen oxides that are diesel’s scarecrow.
Nitrogen oxides have been shown to be carcinogenic, generally harmful, and an inevitable byproduct of diesel combustion in an internal combustion engine.
Higher tuning states making the engines more thermally efficient helped, as did computer control of the injection process.
Ultimately, however, the diesel engine industry decided that the best way to clean up exhaust emissions is to install a Diesel Particulate Filter (DPF).
The filters, however, have proven to be troublesome, leading to critical engine issues as well as much higher tailpipe emissions if they (the DPFs) don’t work properly (as they often seem to be).
Probably the nicest thing you can say about DPF technology is that it is an interim measure, but it will always be compared to spraying perfume on a dog; this will only work until the dog finds something new to integrate.
AdBlue (a solution of about one-third urea and two-thirds water) can help by chemically converting some of the nitrogen oxides into water (vapor) and nitrogen.
But it does require pumps, injectors, reservoirs and controllers (and refills) and works in conjunction with a DPF, not in its place.
As long as a diesel engine is generally more thermal efficient than a gasoline engine and will therefore go further on every liter, the emissions side of things increasingly outweighs this consumption advantage.
The counter opinion is valid for heavy machinery and the transportation industry where fuel economy and range are major financial considerations, but for passenger cars the pendulum moves away from fuel consumption as a sufficient reason.
From a manufacturing point of view, diesel engines are also more expensive to manufacture than a gasoline engine of equivalent performance.
Even though modern gasoline engines also use a turbocharger, they are lighter than a diesel and are easier to pack from a center of gravity perspective.
Gasoline engines have also closed the gap on diesel’s one big advantage: fuel consumption.
While the gap was once large, technical advances in fuel injection, turbocharging (variable vane geometry) and electronic engine management (allowing higher compression ratios) have resulted in great advancements in the Fuel efficiency, to the point that a good gasoline The engine will use very little more fuel than a diesel of the same horsepower.
Another of the big advantages of the diesel engine was its relaxed nature and good low-end torque that worked particularly well with the automatic transmissions that the world now favors.
But improvements in modern transmissions, including dual-clutch and CVT technology, as well as sharp reductions in transmission losses, even in conventional torque-converter automatic transmissions, have closed that gap, allowing gasoline engines to operate. work extremely well in these applications.
The democratization of hybrid transmissions (and stop-go technology) has also pushed the gasoline cause as the constant stopping and restarting of the gasoline engine is much less intrusive in terms of noise, vibration and harshness by compared to a diesel.
And while these factors helped gasoline close the gap over diesel’s advantages, they also gave gasoline an even greater advantage in terms of refinement and handling, not to mention something. as a fun driving experience.
And finally, there is the everyday experience of living with a diesel powered car.
Because it doesn’t evaporate, the diesel will cling to the bowser’s nozzle, and any spill on the forecourt remains for you to stand up on and possibly turn your car’s carpets into diesel sponges.