ny888

Just got a 2008 model, couple of questions:

1. How do you use the kw gauge, for performance, fuel efficiency?
2. Every morning driving my kids to school I have to go up a big hill (at least 1/2 mile) and then down another steep hill (about 1/4 mile). On the downhill, I'm downshifting. Any tips on the uphill drive?

Thanks.

moose66

I can't say for certain, but I think the the lower you stay on that kw guage, in or as close to the blue as possible, the better your gas mileage will be. I am sure someone else will clear this up if I am speaking out of line.

As for your hill question, why are you downshifting as opposed to just coasting? Based on some of my observations when driving and glancing at the display, I can see the car generating power when coasting. To be honest, I have yet to manual/sport shift my car. Just haven't had a need to do so. Maybe if I had a hill to climb I would have.

ny888

The downhill is quite steep. Without downshifting, I pick speed too fast and have to ride my brakes all the way down. Maybe in a hybrid, it's better to use the brakes to regenerate energy?

moose66

I guess you do have a necessity to downshift! It's much better for the life of your brakes.

lucasb7

The power meter shows some sort of odd combination of both power source's output at that moment. I haven't found it to be particularly useful. It is fun to see it shoot up when you gun it though! Like moose66 said, for best mileage try to keep it low. But there are diminishing returns. Somewhat brisk acceleration can actually help mileage. If you think about it acceleration is the least efficient process so why not make it the shortest? Just don't get carried away and go over your desired speed or worse yet, break traction.

As for you question on downshifting, I would avoid doing that. The way the downshifting works is it will basically set a ratio for the PSD to follow, making the engine spin to give you engine braking. However, it doesn't max out regeneration before spinning the engine so you're losing energy. What I do unless I know my battery will be full by the end of the grade is ride the brakes. Just make sure the power gauge in the regen isn't at max. You will notice that when braking the regen gauge will hit a max point for the speed you're traveling at. Try to stay just below that. This way the friction brakes aren't enabled and you're getting all the energy you can into the battery. If it isn't enough then I would resort to using the shifting capabilities.

As for your hill, the most efficient method would be to let your speed drop slowly as you go up it. Depending on its length this could mean starting at 65 and ending at say 55. I know this is REALLY annoying to other drivers so I'd only do this if no one was behind me. But this way you don't have to do as much braking on the other side. You can just let the car coast/accelerate with no power on the way down.

Hope that helps...

moose66

Good info lucasb7! The only advice I was ever told with this car to possibly extend gas mileage was to keep it as low on that gauge as possible. So I tend to do a lot of coasting when I can. With any car, you don't always have to be on the gas. However, this is a heavy car and it certainly doesn't coast very well. But that could be attributed to many things, tires, friction setup for power regeneration, etc.

By the way, ny888, don't forget to get on the hybrid roll call. I see you posted before you picked up your h. Looks like you may be No. 100!

lucasb7

You're correct that this car doesn't coast very well naturally. This is because they have actually programmed in a bit of regeneration when no pedals are depressed. You can notice this phenomenon on the power gauge when you let go of the gas; it will go into the blue range a bit.

To improve coasting you can try to modulate the gas such that the needle is at or just below the line between regen and power. You can use the monitor to help this too. Believe it or not there is a no arrow coast mode but this seems very difficult to reach on the 450h (much easier on the Prius). The no arrow state is the most efficient state for the power train. I sometimes try for it but usually i just aim for just a tiny bit of regen.

ny888

I noticed on my drive yesterday that I was in a no arrow situation while coasting up to a light, was so confused!

Thanks for the advice guys.