You need close to three times (2.78) the energy for accelerating to 50 instead of 30.
If you have to brake, that energy gets converted to heat.
Rinse and repeat. Especially in urban areas where there’s alot of acceleration/deceleration - or just acceleration with different algebraic signs - more speed means more fuel per distance.
There are several graphs floating around showing the fuel consumption at 30 compared to 50 with different gears. It depends on your car and the gear used if 30 uses more fuel than 50. If your car uses more fuel for slower speeds and for such a common speed as 30, the manufacturer is an idiot. There are so many 30 zones in Europe that it really is not an argument against them that a car manufacturer can’t build proper cars.
And since we are also switching to electric cars, that problem will go away in the next decade or two.
Data on this is based on highway driving. Not city driving. Acceleration to 50 and then breaking again will be much less efficient than just driving a in 30
Um, no not really. The gearbox only exists because the engine can only go so fast. The tyres can spin way faster than the engine. For example, you could take your foot entirely off the throttle and still drive 70 in sixth gear while the engine essentially idles. On the other side of the spectrum, the slowest the car can go, while having full contact with the gearbox would be 8 kmh, give or take. So, in the middle of the spectrum you could drive about 30kmh with 3rd gear fully clutched in and the engine on idle. Slower is also possible, naturally. Most cities choose 30 kilometres an hour because that’s when road deaths sharply increase. The reason for this is complex, but one of the main reasons is the field of view. The faster a car goes, the smaller your field of vision becomes. You can clearly see the pavement on your side, the other side of the road, and even some of the pavement of the opposite side. When driving 50, however, you can basically only see your own pavement and some of the opposite road. When doing 130 you can essentially only see your own lane well, with rudimentary details in the other adjacent lanes.
The gearbox only exists because the engine can only go so fast.
Oversimplified. The transmission exists because engines are optimally efficient at specific RPM ranges and the transmission works to keep the engine in those ranges. It/you (auto vs stick) will also downshift to provide more power at the cost of efficiency if hard acceleration is required.
When doing 130 you can essentially only see your own lane well, with rudimentary details in the other adjacent lanes
If you can’t see adjacent lanes, then you’re not scanning properly. This is called tunnel vision and where I live you’ll fail a road test for it. You’d also fail for going 130km/h.
It does not. It would violate simple physics.
Technically it does. Engines are usually less optimized for driving 30 compared to 50, which causes them to use more fuel for the same distance.
But a slightly higher fuel consumption is easily offset by reduced noise and increased safety (for everyone).
You need close to three times (2.78) the energy for accelerating to 50 instead of 30.
If you have to brake, that energy gets converted to heat.
Rinse and repeat.
Especially in urban areas where there’s alot of acceleration/deceleration - or just acceleration with different algebraic signs - more speed means more fuel per distance.
There are several graphs floating around showing the fuel consumption at 30 compared to 50 with different gears. It depends on your car and the gear used if 30 uses more fuel than 50. If your car uses more fuel for slower speeds and for such a common speed as 30, the manufacturer is an idiot. There are so many 30 zones in Europe that it really is not an argument against them that a car manufacturer can’t build proper cars.
And since we are also switching to electric cars, that problem will go away in the next decade or two.
My car is either lugging along in 2nd gear or doing like 3500 rpm in first at 30 kph, so mine wouldn’t be any quieter.
At that speed, most of the noise comes from the tyres. Slower = quieter.
Not with my exhaust
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That’s just not correct
Which part? Can you be more specific as to what you mean?
Data on this is based on highway driving. Not city driving. Acceleration to 50 and then breaking again will be much less efficient than just driving a in 30
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Well, fuel consumption depends on the way you shift gears as well. But yes, it general it’s less.
Ok, I would have to drive in lower gear. That means using more power, higher RPM. Hence higher consumption.
Um, no not really. The gearbox only exists because the engine can only go so fast. The tyres can spin way faster than the engine. For example, you could take your foot entirely off the throttle and still drive 70 in sixth gear while the engine essentially idles. On the other side of the spectrum, the slowest the car can go, while having full contact with the gearbox would be 8 kmh, give or take. So, in the middle of the spectrum you could drive about 30kmh with 3rd gear fully clutched in and the engine on idle. Slower is also possible, naturally. Most cities choose 30 kilometres an hour because that’s when road deaths sharply increase. The reason for this is complex, but one of the main reasons is the field of view. The faster a car goes, the smaller your field of vision becomes. You can clearly see the pavement on your side, the other side of the road, and even some of the pavement of the opposite side. When driving 50, however, you can basically only see your own pavement and some of the opposite road. When doing 130 you can essentially only see your own lane well, with rudimentary details in the other adjacent lanes.
Oversimplified. The transmission exists because engines are optimally efficient at specific RPM ranges and the transmission works to keep the engine in those ranges. It/you (auto vs stick) will also downshift to provide more power at the cost of efficiency if hard acceleration is required.
If you can’t see adjacent lanes, then you’re not scanning properly. This is called tunnel vision and where I live you’ll fail a road test for it. You’d also fail for going 130km/h.