Trade in the Prius for a Hummer to save gas?

[GetRdone]

Sorry if the title sounds like I'm trolling. Bear with me So I got a shiny new '08 Prius and it only has 900miles so far. I haven't gotten around to over-inflating the tires and other suggestions found in the forums.

I've gotten about 46mpg so far. If you drive less than 30miles per day, and you assume that you cold-start the car at least twice a day, it is mathematically impossible to get more than 45-50mpg. Why? It is because of the first 5-10 minutes. During these 5-10 minutes, I get less mileage than a Hummer (finally brought it around). Somewhere between 0 and 17mpg. I've tried different tactics to address this. I tried driving really slow, or getting to the speed limit quickly, and then trying to glide or coast. If I touch the pedal any further than the all-arrows-go-away point, I get 0-17mpg. I get the 0-17mpg regardless of the state of the battery when I start driving. The only exception is when I visited a friend who lives high up on a hill. When I left, it was 100mpg all the way down (off course, getting to his place, I got 25mpg all the way up). Beyond the first 5-10minutes I get great mileage. Discounting the first 5-10 minutes, I get somewhere between 53-65mpg. So in conclusion, if I lived close enough to work, I only used the car to commute to work, and I cold started it at least twice per day, I'd save gas by trading my Prius for a Hummer H1!

Browsing through the forums I haven't seen any solutions to the first 5-10minute problem. Any ideas? Did I miss any posts?

[Neicy]

Solution = Engine Block Heater! I use mine whenever the temperature outside is less than 130F.

[echase]

Welcome to Priuschat, and congratulations on your new hybrid!

First off let's get some flawed logic out of the way: The hummer just like your prius gets SIGNIFICANTLY lower than sticker mileage during engine warmup, (about 50% of sticker). It has a larger engine that takes longer to warmup, and does not benefit from a thermos full of hot coolant like your prius does.

Driving moderately slow during warmup is helpful, I go very slow for the first minute, then moderate for the next five minutes. Pulse/glide does not work until the car is warmed up (you will hear/feel the engine shut down, you can't trust the energy meter during warmup). Expect better mileage after your first oil change, some people see a major break-in boost. If you really want to get better mileage on short drives you can invest $60 in an engine block heater, and a timer, so you aren't leaving it on all night.

[patsparks]

Don't Hummers run a little rich while they warm up? And do you think a Hummer engine with all its mass and metal wouldn't absorb a larger amount of energy to warm up. You would be cold starting the Hummer twice a day still wouldn't you?
If you travel slower in the first 5 minutes and only cover say 1 mile at 17mpg in 5 minutes then resumed normal Prius driving (55mpg) for the remainder of your 15 mile journey you should get an average of over 50mpg.

However, if you really want a hummer, go for it.

[bwilson4web]

I've found with the 2001-03 Prius, the NHW11, using "N" whenever practical seems to cut the warm-up fuel consumption roughly in half. However, any Hummer dealer will gladly take your Prius in trade.

Bob Wilson

[rumpledoll]

All cars get bad gas mileage during the warm up period due to the rich mixture needed in a cold engine. The Prius does better than virtually all cars during this period due to the insulated coolant reservoir which allows the engine to reach operating temperature faster than it otherwise would.

In March 2007 our Prius replaced for daily use a 2002 V6 Ford Explorer. For my wifes daily use ( I take an electric train to work and don't drive during the week) the Explorer got 11.5MPG - 13MPG even though it's rated by the EPA at a combine 15MPG (13/18 City/Highway).

With this same driving our Prius gets in the 35MPG to 45MPG range.

Rumple

[gazz]

Originally Posted by bwilson4web

I've found with the 2001-03 Prius, the NHW11, using "N" whenever practical seems to cut the warm-up fuel consumption roughly in half. However, any Hummer dealer will gladly take your Prius in trade.

Bob Wilson

I've tried different methods to help the first 5 mins. Are we defiantly shaw that it is possible to make an overall difference. I have tried the "N" method but watching the ignition you just seem to be putting off the point it goes to stage 2. The only way to cheat the engine it to heat the block.

I do question the very slow driving at start up, the mpg driving out my estate (slight uphill) seems to sit at about 20mpg but the battery runs quite low which it has to get back. If I drive slightly faster the mpg seems no lower and in fact if I get the speed higher 30mph instead of 20mph the mpg can be higher and it keeps a slightly better SOC.

Is it infact the car just has to warm up. I know driving style can make a difference but just driving slow may not be the answer. A bit faster burns more fuel but warms the engine quicker, so you can glide quicker.

Just my thoughts.

[Danny Hamilton]

If you are actually trying to decide if a Hummer would be better than a Prius for frequent short duration trips, then I echo what others have already said, The Hummer will suffer during warm-up as well and will suffer a lot more than the Prius.

If on the other hand you already realize this, if you are just trying to use controversy to encourage discussion and what you really want to know is how you can reduce your fuel useage during warm-up, then there are a couple of suggestions.

First as several have mentioned, use of an engine block heater even in warm weather can increase the starting temperature of the engine and reduce warm-up time. This will allow you to use less fuel to reach stage 4 operation of the Prius, apparently the most fuel efficient stage of Prius warm-up and operation.

Another option you might want to consider is installing a button that can be used to let the ECU know that you'll be slowing down and stopping and that you'd prefer that the Internal Combustion Engine (ICE) shut off until you need it to accelerate again. Most people refer to it as an EV switch, but really it is far more effective at improving MPG when used in this way. The idea is that during certain stages of warm-up the Prius normally won't shut off the ICE until you come to a complete stop for a few seconds. As soon as you know that you will be coasting for more than a second or two, or as soon as you know that you will be bringing the vehicle to a stop, you can press the EV mode button and (in all but one stage of warm up I think) the ICE will shut off. Then before you need to accelerate again, it is generally best to press the EV button again to turn EV mode off. This way the ICE can be used more efficiently to accelerate, and continue its warm up process. Doing this will extend the amount of time it takes to warm-up the ICE, and as such it will stretch it out over a greater distance. Greater distance means more miles in the miles divided by gallons equation, and therefore more MPG.

Now the remaining, though unlikely, possibility is that you are a creative troll, with little understanding or care about any of this. You seem sincere, but if I'm mistaken, then hopefully this response will be usefull to anyone new who happens to come across your post.

[qbee42]

Another observation is that if you drive less than 30 miles per day, you should consider an electric vehicle, which will completely sidestep all of these warm-up issues.

Tom

[bestmapman]

Anybody who drives less then the warmup cycle, should seriously consider a bicycle. Use the Prius on bad weather days.