[Quietcars] How will the Start/Stop system affect blind pedestrians?

[Robert Wilson]

Hi,

Your article got me curious so I did some measurements and found our Prius and Echo burn about 0.15-0.17 gallons per hour at idle. These cars use the same engine block and because the engine idle rpms are in the same ratio 700-900 rpm, they are functionally identical. To put this in perspective, at 0.15 gallons per hour, it would take six hours and forty minutes to burn one gallon. 

So going back to the Start/Stop savings, the Prius would normally turn off the engine and cycle it just to keep the coolant temperature and electronics running. Several years ago, I measured the Prius parked but ready fuel rate, 0.06 gallons per hour with Start/Stop, versus engine running, 0.17 gallons per hour, about one third the rate. Start/Stop does save some fuel but we're talking very small amounts, disappointingly small.

Driving down the highway at 65 mph, the Prius burns 1.25 gallons per hour and the smaller Echo 1.91 gallons per hour, or about 0.66 gallons extra per hour. That would be just under four hours of constant idle time in the Prius or nearly eleven hours with the default Start/Stop. 

When I commute to work, it takes twenty minutes and less than two minutes are stopped. This means Stop/Start saves a small fraction of my commuting fuel costs. Just many of the buyers of "micro hybrids" were disappointed.

Bob Wilson

> Date: Tue, 5 Oct 2010 12:00:04 -0400
> From: herekittykat2 at gmail.com
> To: quietcars at nfbnet.org
> Subject: Re: [Quietcars] How will the Start/Stop system affect blind	pedestrians?
> 
> Thank you for the explanation, Bob. I really appreciated it as well. I
> don't think these "micro hybrids" will really work in the U.S., . . .