simple trick to save fuel

[Flytox]

Hello Gilgamesh

- on a mountainous route it can even be advantageous to go faster because in the descents the kinetic energy accumulated will be much greater and that is a free energy potential that is regained afterwards by climbing new ones.

Your kinetic energy can be very quickly absorbed (by your brakes) and in a single braking but hardly acquired by your speed during your acceleration ...

You will only benefit if you do not have a good turn down your descent .... which forces you to leave everything in the discs and brake pads ..... In any case you will not do a brake economy.

On a course that you know, count well each time that you really took advantage of your momentum, it will surprise me that you make a difference in consumption.

By the way, don't forget that in the mountains very often visibility is very limited and that "tourists" who are afraid of the void ... drive at 30km / h in the middle of the very narrow road ....

We can't stop you from killing yourself, but make sure you don't kill the others, even if they are driving in the middle of the road ...
A+

[Other]

Hello

The engines are economical when you run them at the speed of their maximum torque and load, even more true on a petrol engine.

So see what diet is your maximum torque.
the gear ratios do not always take account of this often the 5th is for questions of comfort engine noise but not always for the economic speed depending on the speed of the vehicle.
A 3,8-liter automatic Buick petrol engine runs at 1800rpm at 100kmh
A Mercedes diesel engine 3 liters automatic the engine runs at 2500 rpm at 100kmh (RPM of maximum torque)

Andre

[I Citro]

Yes André, but at 1800 rpm on your buick, you are far from the maximum torque of 30 Mkg which is available at 3200 rpm ...
So we can also say that driving under low load can reduce consumption.

Finally I do not agree with Gilgamesh when he says that driving 120 or 140 does not change much the consumption! He makes them how his measures!
The energy expended to enter the air increases with the square of the speed, NO?

In the 60s "economy races" took place, the Mobil Economy Run cars like the Panhard dyna (4.72l / 100) or the DS19 (6.06l / 100) achieved these feats by not exceeding 80km / h

Finally on your photo we can see a pressure gauge of aeronautical type (beautiful stuff) but I do not understand what are the units expressed.

[gilgamesh]

Hi,

For Flytox: Of course I am referring to mountainous highways

For Citro:

I make the Lisbon-Zaragoza journey quite often, it's 950 km of highway with very little traffic. I have done this ten times always with the same car and it is a fairly exact way of controlling consumption. By driving as economical as possible at 115-120 it gives me 7,9 liters / 100km. While driving at 145km / h I have already consumed 8,15 lt. - but in general it is 8,3 lt. I checked it on each trip. With the same car driving like an old man on the national road Lisbon-Faro I already consumed 6,3lt / 100. The car is saab 9000 i, 1988, petrol 2000cc.

The mountainous route is Madrid-Zaragoza if you don't know it you have to visit this region, it's worth it.

[Eloi]

If in both cases (115-120 and 145 km / h) you drive in 5th gear, I would say that at 145 km / h the efficiency of your engine is better than at 120 km / h.
What is certain is that as citro said, the friction of the air is proportional to the square of the speed, and at this speed, it is almost the only friction to take into account because the others are very little ones in front of him.
So your engine develops more power when you drive 145 than 120.
But maybe at 120 in 5th you have a very poor performance while at 145 in 5th you are at maximum performance.
You would have to try the same route at 120 in 4th. I'm sure you would consume less than in the other two cases. At 120 in 4th you have to be roughly at the same engine speed as at 145 in 5th, but as you go slower there is less friction, therefore less power to provide, therefore less consumption.

Note that I assumed quite a few things:
-that you were in 5th in the two cases that you cited
-that the engine speed is the same at 120 in 4th and 145 in 5th

Eloi

[Other]

Hello

Finally on your photo we can see a pressure gauge of aeronautical type (beautiful stuff) but I do not understand what are the units expressed.

It is a defective instrument which was on a two Piper Azteck engines there were two needles one side was faulty, I eliminated it

Normally we use this to calibrate the propellers with variable pitch it is an indication of the engine thrust
the instrument is graduated in inches of Mercury (all planes even in Europe work with these units (even the altitude is expressed in feet by French pilots)
So at atmospheric pressure at rest, this instrument indicates 30 inches of mercury, the absolute vacuum would indicate zero,
at slowdown it goes down around 10 inches in decelleration it can go to 4 inches of mercury and full gas it goes up to 29 inches.

On an airplane we adapt the engine speed with the inches of Mercury
Example 2300 rpm pressure 23 inches 2500 rpm pressure 25 inches

An engine must be loaded on a certain engine aircraft if the load is not sufficient, there are segment problems.

What is certain is that as citro said, the friction of the air is proportional to the square of the speed, and at this speed, it is almost the only friction to take into account because the others are very little ones in front of him

.

I am not sure that the others are negligible the pneumatic tread consumes pa smal of energy, according to its design, the kind of rubber, the condition of the road surface
The aerodynamic part under the car has an importance, Citroen had treated it with its DS, now it puts skirts or deflectors to prevent the air from circulating below.

For example, a plane taking off on a long runway, just keeping the wheels in contact on the concrete runway, without pressure just letting them spin, full throttle, you can't reach your cruising speed as soon as the wheels drop speed increases rapidly ..

Andre

[Woodcutter]

Recent experience, I just beat my consumption record, with around 1500 km for a full tank, which leads to 5.63 l / 100 (XM Turbo D12).

Profile of the route: national roads at 95 km / h, expressways at 115, as well as 170 km of motorway at 135 km / h.
Between Paris, Roanne, Lyon, Grenoble, Macon, etc ... so not only flat but not strong reliefs either.

It is my lowest consumption since I got the car and it is certainly not a coincidence if it comes when I have not been on the highway ...

Consumption verified on 400 km of highway 135, in spring: about 7 l / 100 km.

What do I deduce from this? With Ma car, the more I drive slowly (by not going down too much under the 90 except the crossings of agglo) and the less I consume.
Speed ​​in 5th gear: around 45 km / h for 1000 rpm. Maximum torque 25 mkg at 2000 rpm.

[gilgamesh]

Consumption verified on 400 km of highway 135, in spring: about 7 l / 100 km.

What do I deduce from this? With Ma car, the more I drive slowly (by not going down too much under the 90 except the crossings of agglo) and the less I consume.
Speed ​​in 5th gear: around 45 km / h for 1000 rpm. Maximum torque 25 mkg at 2000 rpm. [/ Quote]

It is true that with diesel it is not the same thing. I myself made 4000 km this summer 3000km highway at 130 km / h + 1000 km national road. I arrive at an average consumption of 7,8 lt./100km which is quite good for a 2000 cc petrol car. I just use the vortex in the intake and the tire pressure at 3 bar. Without acetone or hidrogen. This is a saving of 2,6-15% compared to the normal consumption of this car.
The vortex effect is a subject to study _ I saw a pantone mount on quanthomme of a Mercedes delivery 3 liter which uses a vortex before the reactor and another at the exit of the engine exhaust and it says that increases the efficiency of its pantone system.
I followed André's advice - according to him the ideal petrol engine is 3200 rpm. So I always drove at a speed of 3200-3500 rpm and it is true that the engine is very efficient like that.

[Other]

Hello

I followed André's advice - according to him the ideal petrol engine is 3200 rpm. So I always drove at a speed of 3200-3500 rpm and it is true that the engine is very efficient like that.

I don't think I was as categorical, the speed is different from one engine to another, it is the speed of the maximum torque
In my deisel it's 2400Rpm on a big V8 it can be 2000 rpm on a Lycoming o-290 2250rpm.
Each engine has its peculiarity and each engine has an economic speed which is different between a diesel and a petrol, a diesel can be economical at low RPM, whereas a too closed butterfly petrol engine becomes more greedy than if it is in chage at maximum torque ..
The efficiency is calculated according to the power supplied by the engine versus the consumption.
On a car the speed exceeded 90kmh according to its aerodynamic design, this requires more power
It is necessary to adapt the engine speed which goes with the power
Note that at low speed on a petrol engine it is more economical to drive in 4th gear than in 5th gear


Andre

[Cuicui]

Recent experience, I just beat my consumption record, with around 1500 km for a full tank, which leads to 5.63 l / 100 (XM Turbo D12).

My recent record: 1033 km with a full 49 l, or about 4,75 l / 100 (ZX breack TD) . If I had put magnets, capsules, a vortex, acetone or water doping, I would be blowing these processes to the skies. For the moment, still none of this, (but it will come), I simply stay if possible below 2000 rpm and I declutch in the descents.
But it's much slower and more comfortable than an XM