Questions & Observations about new RX450h
07-19-12, 01:30 PM
#1
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Questions & Observations about new RX450h
I've only had my first hybrid, a 450h for several weeks, so my observation is this; driving a hybrid is different.
For the first 2 weeks, I only drove it on very short trips of about 3 miles and saw my average mpg hover around 26. The first "lengthy" drive was bringing my car to the dealer to swap the Dunlops for Michelins. When driving off, I reset the average mpg indicator and when I got home, it read 40.7. That drive was on a boulevard with several traffic signals and I have to admit I attempting to be a professional hypermiler.
Since then, my average mpg has stayed around 31-32, which includes about 150 miles of 65-70 mph Interstate travel and my short 3 mile trips. I'm very satisfied with the economy at this point. I do have the Eco setting turned on and I do try to conserve fuel.
My questions are these. Could the lower fuel economy during my first 2 weeks be because:
1. When I took delivery of my car, the hybrid batteries were not sufficiently charged?
2. Because of my short, once a day 3 mile trips, the batteries could not regain enough charge to fully assist the gasoline engine?
3. Beginning to use the car for longer trips allowed the batteries to recover enough to do their job?
When I first started driving the car, I tried to stay out of the "Power" section, but soon realized I was using more fuel accelerating slower, but for a longer period of time. Now I accelerate "normally" and get out of the "Power" section much sooner by slightly lifting off of the accelerator. This method seems to help increase fuel economy.
I find this learning curve pretty interesting and contributes a lot to the enjoyment of owning a hybrid. Maybe driving this conservatively will wear thin after a while, but for now, It's a lot of fun.
For the first 2 weeks, I only drove it on very short trips of about 3 miles and saw my average mpg hover around 26. The first "lengthy" drive was bringing my car to the dealer to swap the Dunlops for Michelins. When driving off, I reset the average mpg indicator and when I got home, it read 40.7. That drive was on a boulevard with several traffic signals and I have to admit I attempting to be a professional hypermiler.Since then, my average mpg has stayed around 31-32, which includes about 150 miles of 65-70 mph Interstate travel and my short 3 mile trips. I'm very satisfied with the economy at this point. I do have the Eco setting turned on and I do try to conserve fuel.
My questions are these. Could the lower fuel economy during my first 2 weeks be because:
1. When I took delivery of my car, the hybrid batteries were not sufficiently charged?
2. Because of my short, once a day 3 mile trips, the batteries could not regain enough charge to fully assist the gasoline engine?
3. Beginning to use the car for longer trips allowed the batteries to recover enough to do their job?
When I first started driving the car, I tried to stay out of the "Power" section, but soon realized I was using more fuel accelerating slower, but for a longer period of time. Now I accelerate "normally" and get out of the "Power" section much sooner by slightly lifting off of the accelerator. This method seems to help increase fuel economy.
I find this learning curve pretty interesting and contributes a lot to the enjoyment of owning a hybrid. Maybe driving this conservatively will wear thin after a while, but for now, It's a lot of fun.
07-19-12, 07:57 PM
#2
The traction battery may charge and discharge many times a day. It was probably "sufficiently" charged by the time you left the dealer's lot. If not recharged by regeneration, the internal combustion engine will run to charge the battery.
07-19-12, 09:30 PM
#3
If you just drive the car normally, it will often fall into the 26 to 27 MPG range. That is not surprising for a new owner and new car. The 40 MPG average happens if you reset the car after it is warmed up, has a good charge and you are just driving in town under good conditions. I've gotten as high as 66 MPG ... but, it doesn't mean anything because under normal operation your average will drop back to the EPA range. The car goes through an adjustment period where it analyzes your driving style. Since you have been driving for mileage, the car is adjusting to that driving strategy. Your car is working correctly.
Enjoy the conservative driving while the feeling lasts ... it does wear thin very quickly IMO. The good news is that the 450h has a lot of power and still gets OK mileage when driven normally.
Enjoy the conservative driving while the feeling lasts ... it does wear thin very quickly IMO. The good news is that the 450h has a lot of power and still gets OK mileage when driven normally.
07-20-12, 08:48 AM
#5
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Actually, I only have about 300 miles on my car now. I haven't even added gas since I took delivery. The only change to my car is the swap of the Dunlops for Michelins and I'm sure that doesn't account for the 6-7 mpg increase in fuel economy. Maybe the ECU is getting to know me better and I about hybrid techniques. Whatever the reason, it's all good.
07-20-12, 08:49 AM
#6
Lexus Test Driver
Actually, I only have about 300 miles on my car now. I haven't even added gas since I took delivery. The only change to my car is the swap of the Dunlops for Michelins and I'm sure that doesn't account for the 6-7 mpg increase in fuel economy. Maybe the ECU is getting to know me better and I about hybrid techniques. Whatever the reason, it's all good.
. But, yes, the ECU is definitely learning your habits and that does have an impact on mpg.
07-20-12, 09:47 AM
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when you drive for 3 miles and other short trips, the engine is not fully warmed up and so leads to inefficiencies. Then because the engine is not warmed up, the car will not use its hybrid system as often, meaning the engine will remain on for longer periods of time. The car will seldom use hybrid power alone until the engine temp needle hits the two tick mark, and then the engine will shut off more frequently.
If you are accelerating from a start, I found that it is best to accelerate at the pace you want even if you are in power mode, and when you get to your desired speed, release the gas pedal enough so that the power meter goes down to below/or at the quarter of the green zone. This will automatically shut off the engine, and the car will run on electric and you can usually keep that in electric to keep the car at a steady pace, up to about 40mph. Going over half of the green zone will start back up the engine.
Does that make sense?
If you are accelerating from a start, I found that it is best to accelerate at the pace you want even if you are in power mode, and when you get to your desired speed, release the gas pedal enough so that the power meter goes down to below/or at the quarter of the green zone. This will automatically shut off the engine, and the car will run on electric and you can usually keep that in electric to keep the car at a steady pace, up to about 40mph. Going over half of the green zone will start back up the engine.
Does that make sense?
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07-20-12, 01:08 PM
#9
when you drive for 3 miles and other short trips, the engine is not fully warmed up and so leads to inefficiencies. Then because the engine is not warmed up, the car will not use its hybrid system as often, meaning the engine will remain on for longer periods of time. The car will seldom use hybrid power alone until the engine temp needle hits the two tick mark, and then the engine will shut off more frequently.
If you are accelerating from a start, I found that it is best to accelerate at the pace you want even if you are in power mode, and when you get to your desired speed, release the gas pedal enough so that the power meter goes down to below/or at the quarter of the green zone. This will automatically shut off the engine, and the car will run on electric and you can usually keep that in electric to keep the car at a steady pace, up to about 40mph. Going over half of the green zone will start back up the engine.
Does that make sense?
If you are accelerating from a start, I found that it is best to accelerate at the pace you want even if you are in power mode, and when you get to your desired speed, release the gas pedal enough so that the power meter goes down to below/or at the quarter of the green zone. This will automatically shut off the engine, and the car will run on electric and you can usually keep that in electric to keep the car at a steady pace, up to about 40mph. Going over half of the green zone will start back up the engine.
Does that make sense?
08-18-12, 03:07 PM
#10
Lexus Test Driver
when you drive for 3 miles and other short trips, the engine is not fully warmed up and so leads to inefficiencies. Then because the engine is not warmed up, the car will not use its hybrid system as often, meaning the engine will remain on for longer periods of time. The car will seldom use hybrid power alone until the engine temp needle hits the two tick mark, and then the engine will shut off more frequently.
If you are accelerating from a start, I found that it is best to accelerate at the pace you want even if you are in power mode, and when you get to your desired speed, release the gas pedal enough so that the power meter goes down to below/or at the quarter of the green zone. This will automatically shut off the engine, and the car will run on electric and you can usually keep that in electric to keep the car at a steady pace, up to about 40mph. Going over half of the green zone will start back up the engine.
Does that make sense?
If you are accelerating from a start, I found that it is best to accelerate at the pace you want even if you are in power mode, and when you get to your desired speed, release the gas pedal enough so that the power meter goes down to below/or at the quarter of the green zone. This will automatically shut off the engine, and the car will run on electric and you can usually keep that in electric to keep the car at a steady pace, up to about 40mph. Going over half of the green zone will start back up the engine.
Does that make sense?
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