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Efficiency with combustion engines - the fuel saving report

Regardless of the explosion in fuel prices: Modern combustion engines work extremely efficiently, as our tests show. And how can the savings potential be used?

A conventional Wednesday morning at the gas station of trust: the two employees lose themselves in an extremely pitiful dialogue, talk about lack of sleep and an acute reluctance to work. However, they acknowledge the suggestion that this acute reluctance to work with the acute reluctance to pay 45.3 liters of Super E10 at 2.10 euros each tacitly lead to a magnanimous omission of the payment process, but they acknowledge it with a wry smile. Sure, the current fuel prices really don't make drivers rejoice, even if Germany still doesn't look that bad in a European comparison.

Much more important, however: This way, the focus can be directed to the current generation of combustion engines - and their remarkable efficiency. On the following pages you will find some impressive examples, sorted according to the three most economical models in their segment. On the basis of unrealistic test bench measurements and information from the manufacturer? Of course not. This is based on measured values ​​from auto motor und sport, above all the so-called eco-consumption. It shows the maximum savings potential of a vehicle, but under realistic driving and traffic conditions.

The list also includes one model each with the greatest savings potential, which is measured according to the delta between eco and sports driver consumption, which is when driving at a constant speed of 160 km/h plus further consumption information from a comparative trip on country roads and the motorway is determined. Incidentally, this delta does not necessarily speak for the qualities of an engine, at least not as long as it is over 90 percent. Rather, it underpins the design of a drive for markets in which there is a strict speed limit.

Hybrid? Doesn't always help

This often includes hybrid models from Japanese manufacturers, which reveal immense savings potential with a moderate driving style, and often occupy the top positions in their segment. The Honda Jazz can be moved with only 4.1 l/100 km, which is only slightly above the manufacturer's specification of 3.7 l/100 km. The small car tries three engines for this – one combustion engine, two electric units. However, the naturally aspirated petrol engine often only generates electricity for the electric drive units and then has no effect on the drive wheels. But as soon as the system output of 109 hp is used more frequently, consumption jumps to 8.8 l/100 km, which corresponds to a delta of 114.6 percent. With a test consumption of 5.1 l/100 km, the Jazz is still one of the stingy kings, but costs at least 22,850 euros because of the complex drive. For comparison: the Dacia Sandero TCe 90 is available from 11,750 euros.

Its 1.2-liter turbocharged petrol engine allows for an eco-consumption of 4.7 l/100 km, the sports driver consumption is 8.3 l/100 km, which results in a delta of 76.6 percent. The test consumption: 6.0 l/100 km. So don't drive so fast? Naturally. Hardly anyone will probably do it. So maybe Honda shouldn't advertise the Jazz as a "sporty small car". But it is also clear: the price for the hybrid model is just as sporty. Even more economical, but also more expensive: small cars with diesel engines like the Opel Corsa. It costs at least 23,730 euros, gets by on the eco lap with 3.8 l/100 km, and does not need more than 7.0 l/100 km for sporty driving. And what about an electric car? Take the Corsa-e, for example: Sure, it only uses electricity, but it doesn't come for free - and the car certainly doesn't. A Corsa-e costs at least 32,895 euros before deducting the premium, of course, but with the known limitations in terms of range and infrastructure. Its biggest advantage: driving pleasure, but that's another topic.

ams-Eco-Round: The consumption determination


Just listen to the car

Crucial, however: How can the maximum range be obtained from each liter of expensive fuel? As is so often the case, the answer sounds simple: Do what you are told. In this case from the car. It starts with the gearshift recommendation, although fewer and fewer models are equipped with a manual gearbox. And what else? Use Eco mode if available. In this driving program, the name of which varies depending on the manufacturer, the response of the engine, the shifting characteristics of the transmission and the way the air conditioning works change. In models with air suspension, the body can also be lowered to reduce driving resistance. In addition, some models (including those from the Volkswagen Group) give tips that may come across as a bit cheeky, but are actually true - such as "avoid running the engine when stationary" or "close the windows" when the car is moving. There's even more: Eco Assistants use data from the navigation system to indicate when it might make sense to take your foot off the gas pedal at intersections, roundabouts, city limits and speed limits. If desired, there is even a haptic signal in the accelerator pedal. In this way, the drive technology can be optimally used, be it a pure combustion engine, a mild or even full hybrid like the Honda mentioned at the beginning. Even powerful engines in particularly sporty models or even sports cars have to make their contribution to CO2 reduction, work with cylinder deactivation and coasting function, such as in Mercedes-AMG, Lamborghini and Corvette. The four-liter V8 engine used by Porsche, Audi and Bentley also offers these features.

Would you like a small extreme example? The Bentley Bentayga V8, which weighs 2518 kg and has 550 hp, consumes 9.9 l/100 km on the eco lap, and the test consumption is 13.9 l/100 km – quite impressive figures for a vehicle of this caliber. If you want to drive an SUV of this size and value economy, you can't avoid a diesel. Example of this: the seven-seater Mercedes GLS 400 d, which is another 100 kg heavier. Its in-line six-cylinder diesel consumes just 7.9 l/100 km, the test average is 10.2 l/100 km.

One last, admittedly very wacky example: Lamborghini Huracán STO – manages with 10.9 l/100 km. But with the 640 hp ten-cylinder sports car, only very few owners will succeed. Nevertheless: These extremes show how efficient combustion engines are today - and further progress is becoming apparent, with new charging systems (e-turbo) as well as even higher injection pressures and combustion processes (pre-ignition).

Plug-in hybrids are missing for a good reason


Test bench prose? Gone

But even the current technology proves that the consumption data from the manufacturers are not completely out of thin air. Taped body gap? Smallest possible wheels? Possibly folded or dismantled exterior mirrors? And then off to the dynamometer under clinical conditions? That was NEDC (New European Driving Cycle) and that is now history. Incidentally, this also applies to the extremely downsized engines – i.e. with extremely small cubic capacity with high supercharging – which achieved extremely low values ​​on the “roller”.

In reality, however, consumption often shot up disproportionately just beyond the recommended motorway speed. This could only be overcome with expensive, particularly heat-resistant materials, which made internal cooling with fuel obsolete.

In the meantime, cubic capacity counts for something again, for example, two liters are the measure of all things for a four-cylinder engine. In addition, the overall driving resistance is increasingly reduced, which is why cars roll for a long time - often with the engine switched off ("sailing"). This also explains why the values ​​determined by auto motor und sport do not deviate significantly from the factory specifications.

The cars enable that kind of fuel-saving driving style without giving the feeling that you were treating your car badly. Load requirement at just over 1000 revolutions? Often goes without switching back. Important: The testers do not complete the ams-Eco-Run as a traffic obstacle. Instead, swimming with the traffic is the order of the day, i.e. speedy acceleration. Tricks such as turning off the air conditioning, navigation system and radio are also not permitted. And above all: the correct tire pressure is present, not too high! Too much pressure in the tires is at the expense of driving safety, which in turn reduces the (questionable) fuel saving potential ad absurdum.

So it's all the more impressive that current cars can be driven economically with all the safety devices required by law and the space and comfort desired by the customer. Like the BMW 520i with 5.8 l/100 km or the VW Golf 2.0 TDI with 4.4 l/100 km. Maybe that will lift the spirits at the gas station a little - for everyone involved.


Even if the constantly growing selection of models and the lavish state subsidies make electromobility more attractive - cars with combustion engines are still the larger and often cheaper offer, high fuel prices or not. Anyone who then consistently uses the potential of the drive technology can achieve remarkably low consumption values. This applies to every segment, whether it's a small car or a spacious SUV. And it is already clear today: the next evolutionary stages of petrol and diesel engines are even more stingy.


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