Pulse and glide test results: VW Up!

[Retardosaurus]

Hello fellow ecodrivers

I tested P&G, in my stock VW Up! (1,0 liters gasoline, 60 BHP), versus driving with constant speed. The average speed of all runs was 50 km/h (30 MPH).
Since my car is stock, the glides was performed with engine idling.
The pulses was from 24 MPH -> 36 MPH.

The test course was 2,2 miles of smooth tarmac, without elevation and lights, no traffic interfering and a few 30MPH bumps.
Engine warm, calm and dry weather and temperatur around 20 *C.
I havent bought a Scanguage yet, so the test was performed with the factory installed trip computer, which is shows a fuel consumption approx 5% lower than reality.
This is the measurement from my 4 runs:
1 out: Constant speed: 2,70 l/100km (87,1 MPG (us))
2 back: Pulse and glide: 2,80 l/100km (84,0 MPG (us))
3 out: Pulse and glide: 2,80 l/100km
4 back: Constant speed: 2,70 l/100km

Afterwards I wanted to calculate potential fuel saving, if I was able to turn the engine off.
By observing pulse and glide times and consumption, during the tests, I calculated theoretical P&G fuel consumptions with engine idling and engine off during the glides.
Calculated fuel consumption with P&G with engine idling: 2,89 l/100km
Calculated fuel consumption with P&G with engine off: 2,11 l/100km

The result: P&G in the test showed an increased fuel consumption 3-4% compared to driving with constant speed.

If I was able to turn off the engine of during P&G, I would certainly get lower fuel consumption.
From my guesstimations it would result in a 20-30 % decrease in fuel consumption compared to constant speed.

[oldtamiyaphile]

Thanks for the results.

Bare in mind that instrumentation's accuracy (factory or SG), will vary depending on how the car is driven.

On my Fiat the factory display is about 2% optimistic for most drivers, but for us Eco types it's actually about 2% pessimistic. Same goes for SG, it's only accurate once you calibrate it to your driving style, change style and the calibration goes out. It can make you think you're saving fuel with a new technique until you fill up and realise it was just a way of fooling the instruments.

I've found that engine on P&G just doesn't work on the Fiat's little 2cyl engine (too light and poor aero), can't really do EOC because it's a turbo. It's the car that can't be hypermilled.

[MetroMPG]

What is it about your Up that prevents you from stopping the engine?

[Retardosaurus]

Originally Posted by MetroMPG

What is it about your Up that prevents you from stopping the engine?

I dont wanna mod my new car with a kill switch, since its brand new and its everyday car. And I dont like turning the ignition off and risking locking the steering wheel.

[MetroMPG]

Fair enough.

[oldtamiyaphile]

Originally Posted by Retardosaurus

I dont wanna mod my new car with a kill switch, since its brand new and its everyday car. And I dont like turning the ignition off and risking locking the steering wheel.

Kind of a shame because in my Fiat with EPAS, the EPAS continues to work in EOC. In fact it does the opposite of what most cars would do and goes into parking mode which makes the steering extemely light. I don't really EOC out of sympathy for the turbo though.