Smooth Driver Fuel Saver

[ivanlaud]

I have invented a completey new dashboard fuel saver which I call the 'Smooth Driver' It is simple but very effective. The best way to appreciate a dynamic device like this is to see it in action - you can see it on YouTube - just enter 'Mark11 Smooth Driver Fuel Saver' into google or You tube.
I would be grateful to receive ant comments and can explain detail if required.

[GasSavers_Erik]

Welcome to the site.

This is a great idea and could help those who brake hard to train themselves to coast to a stop/brake more gently- they would definitely save fuel by using this device.

On this site, we have discussed how moderately brisk acceleration can reduce pumping losses (increase efficiency) and actually save fuel in gasoline powered vehicles. There is an advanced driving technique called "pulse and glide" to maximize mileage, but the brisk acceleration would not mesh well with the "smooth driver" device since it would likely involved getting up into the "red" section of the device's measurement range during the "pulse".

[8$PG]

It's a nice idea. But as mentioned the smoothest ride isn't always the most fuel efficient. A lot of times braking hard and short because of earlier or later reactions to possible changes in traffic is better than breaking long and slow. Cornering fast is also beneficial so you don't have to use the brakes. Fast acceleration uses the engine more efficiently.

Using both the gas and brakes at the same time also tends to smooth the ride but gives horrible mileage.

[ivanlaud]

It is best whereever possible to anticipate the situation ahead in good time avoiding too much braking and unecessary loss/ wastage of momentum which results. The same is true of cornering.
Any hard braking or cornering will also have the secondary effect of worsening tyre wear significantly. I can asssure you of this as I worked in the tyre business and was for a while responsible for tyre wear testing. For medium severity tests, the test drivers had electronic accelerometers on the dashboard and had to observe a maximum g force for braking , acceleration ,and cornering of 0.3

[GasSavers_BEEF]

But, but, but....

I agree with you that hard braking is a bad idea. Any time you give up energy to heat (especially forward momentum in a car) it is not efficient. My issue is that hard cornering keeps your inertia going where you want it and you use less energy/pedal to keep a given speed after exiting the corner. Also, it used to be that at WOT (wide open throttle) cars would go into fuel enrichment and simply dump fuel into the motor to achieve power and your A/F ratio truly went to crap. In many (if not most) modern cars, they use wide band O2 sensors and thus they can keep the A/F ratios the same with a closed loop vs reverting to a fixed fuel map and open loop even at WOT.

I understand that rapid acceleration and hard cornering are not good for tires but they are actually good for efficiency. I have an older car so I am limited to around 75% pedal before I go into open loop and fuel enrichment but I usually take off very briskly and have seen pretty good mileage with my technique. This also helps an automatic transmission get into a situation of torque converter lockup faster and thus even better transfer of energy from the motor to the tires.

[JanGeo]

I watched the video and it seems like a great idea, I'm just surprised you haven't come up with a level that faces you instead of being at an angle like that one was. Tire cost is also much less per mile than gas cost so saving some gas with a little extra tire wear is OK, most of us run higher pressure which tends to help reduce tire wear on hard cornering anyway. Mine needed to be replaced before they wore out because they got cracked from age and the new ones should go twice the miles.

[8$PG]

I want to explain a bit what I mean by braking hard and short, early or late.

Depending on the situation, say if the lights ahead turn to red, braking hard and short and then coasting in gear can help maximizing your minimum speed by prolonging the time it takes to reach the lights and by this minimizing the total loss of inertia. This way it is more likely you don't have to stop before the lights turn green and the total amount of braking is less.

Another possible scenario is a yield sign with little risk of having to give way. In this case planning for not using the brakes at all is the most likely outcome, but in case of having to give way you can always brake hard and short "at the last minute". This is more of a probability controlled way of saving fuel. Braking late can also in the long run contribute to a behavior of early coasting towards situations maximizing the time your engine is in DFCO-mode.

I realize this is probably a bit advanced and most people would do better just taking it easy and not rushing into situations making late decisions. In this case smooth is certainly better.

[ivanlaud]

I originally worked with an electronic accelerometer but these are too expensive. I then looked for a low tech mechanical solution and settled on adapting a suitable ball in tube inclinometer tube. These fluid filled tubes give just the right damping to the ball movement to avoid overun.The tangent of the angular movement of the ball from zero is directly g force so the maths is very straight forward. I use a plus or minus 10 degree tube which is perfect for smooth driving.
I initially alligned the tube in the direction of travel which catches braking and acceleration but it needed a mirror at 45 degrees so the driver could see it. I didn't like the idea of glass on the dashboard and then found out with the just the tube at 45 degrees it still picked up braking and acceleration and gave me cornering too. With this arrangement the driver has all the driving forces on the one clear analogue scale. The tube also of course picks up acceleration due to gravity so acts as a sort of spirit level for inclines.This is very useful as I show in the video.

[JanGeo]

I see but a mirror does not have to be made out of glass, it could be a very shiny metal reflective surface and if you had two bubble levels at 90 degrees you could have pure cornering on one and acceleration and deceleration on the other and viewing the top with the mirror would give you a nice cross display.

[ivanlaud]

I tried numerous combinations but for a dashboard instrument the key thing is for it to be driver friendly and appreciated at a glance. At one point I had 2 tubes, one for braking and acceleration, and another for cornering, but it's too much for the driver to absorb rapidly. Incidently, this is why the analogue scale rather than anything digital is much better. It may be low tech but in this case it is superior.
The solution I finally arrived at is the neatest and sitting at the centre of the dash at 45 degrees it is nicely visible to the driver and but not obscuring his forward view, important for safety.
The tube shows a lot of information in one scale but as the direction and reaction of the ball relates to what we feel in our body it presents no problem and works well.