RX 450h EV Mode
04-22-14, 06:49 AM
#31
I do the pulse mode all the time and agree that it works well. The few times that I've been able to do the whole bit - EV to start, slow acceleration above 25 mph to minimize the ICE from coming on, pulse mode by backing off the throttle and then "cruising" - the average mpg did jump up.
I think I've driven the RX450h in a number of different situations to get a good feel for how it operates, though I'm still learning.
It is my opinion (not yet based on any solid facts) that if I could manually engage a "don't use the ICE button", I could do even better than my current mpg. I think the current EV mode restrictions are a bit too "tight" and that using the grey matter in my head (a beautiful organic computer), I can manage the operation of this vehicle quite nicely.
Note that I also drive a completely non-computer driven stick-shift Toyota Tacoma truck from the 1990s and do quite nicely in it in regards to shifting, optimizing the engine load, etc. When I want cooling air without the A/C, I can roll the windows down. If I want intermittent wipers operation, I turn them on for a few seconds, and then off. When it gets dark out, I know it is time to turn on the headlights.
The RX is a nice contrast to it.
I guess I just like more control over my vehicle than the Lexus Engineers built into it.
I think I've driven the RX450h in a number of different situations to get a good feel for how it operates, though I'm still learning.
It is my opinion (not yet based on any solid facts) that if I could manually engage a "don't use the ICE button", I could do even better than my current mpg. I think the current EV mode restrictions are a bit too "tight" and that using the grey matter in my head (a beautiful organic computer), I can manage the operation of this vehicle quite nicely.
Note that I also drive a completely non-computer driven stick-shift Toyota Tacoma truck from the 1990s and do quite nicely in it in regards to shifting, optimizing the engine load, etc. When I want cooling air without the A/C, I can roll the windows down. If I want intermittent wipers operation, I turn them on for a few seconds, and then off. When it gets dark out, I know it is time to turn on the headlights.
The RX is a nice contrast to it.
I guess I just like more control over my vehicle than the Lexus Engineers built into it.
lol @ caveman Tacoma tactics. I remember them well.
04-22-14, 08:36 AM
#32
Lexus Champion
Actually, driving in EV mode for extended distances would be counter-productive to MPG. At some point, ICE will kick-in to supplement the battery. As many mfgs (cough Chevy Volt cough) have learned, a series-hybrid, where the gas engine charges the battery to later drive the electric motor is not as efficient as a direct energy transfer from the engine to the wheels.
So, the battery level has to be kept in a sweet spot, where it is not too charged, nor too discharged. That way, going downhill or braking will recover energy and accelerating or going uphill will drain it. The software is very well-tuned to do exactly that.
When we had our Prius, we would play the best MPG game. More often than not, my wife would accelerate more aggressively and would get better MPG.
So, the battery level has to be kept in a sweet spot, where it is not too charged, nor too discharged. That way, going downhill or braking will recover energy and accelerating or going uphill will drain it. The software is very well-tuned to do exactly that.
When we had our Prius, we would play the best MPG game. More often than not, my wife would accelerate more aggressively and would get better MPG.
04-22-14, 10:17 AM
#33
Vlad_a - that is interesting! I've thought that using the EV for short distances and dropping the battery level down a bit would usually pay off with a downhill or coasting to regenerate. This does not always happen, but fairly often does.
It does make sense that the ICE direct to the wheels is more efficient than the ICE to battery to electric motors to wheels. The only way to offset that inefficiency is to get regenerative power generation some how.
In our specific case, we back out of the garage going slightly uphill, then out on the level street for a bit, then down a short hill, level again, then down a long hill to the main road. This is over the course of less than 1/2 mile. So for that part of our trips, I think the EV mode out of the garage to the first downhill would be great - and then we'd get the battery nicely recharged on the two downhills.
For the rest of any trip, it is just like anyone else. Then eventually we have to go up those two hills to get home where we always lose a bit of mpg.
It does make sense that the ICE direct to the wheels is more efficient than the ICE to battery to electric motors to wheels. The only way to offset that inefficiency is to get regenerative power generation some how.
In our specific case, we back out of the garage going slightly uphill, then out on the level street for a bit, then down a short hill, level again, then down a long hill to the main road. This is over the course of less than 1/2 mile. So for that part of our trips, I think the EV mode out of the garage to the first downhill would be great - and then we'd get the battery nicely recharged on the two downhills.
For the rest of any trip, it is just like anyone else. Then eventually we have to go up those two hills to get home where we always lose a bit of mpg.
04-23-14, 05:53 AM
#34
Racer
I have always found that to be the case. Cruising/coasting is where you turn a bad drive into an exceptional one. This idea of slow gradual acceleration just doesn't yield good results on a Toyota hybrid generally. Get up to speed moderately quickly and get into steady speed. Just the same as a gradual uphill is terrible on gas mileage, but the same destination involving ups and downs can be done quite efficiently.
I think this has as much to do with software as it does with physics. When accelerating (or maintaining speed uphill, even slight uphill) unless you've floored it, the battery assistance is negligible, it's 99% gasoline power. I know the graphical displays will show battery assistance, but I've never seen the on & off battery assistance in these situations make much of a difference on the FE gauge. It's slight at best.
I think this has as much to do with software as it does with physics. When accelerating (or maintaining speed uphill, even slight uphill) unless you've floored it, the battery assistance is negligible, it's 99% gasoline power. I know the graphical displays will show battery assistance, but I've never seen the on & off battery assistance in these situations make much of a difference on the FE gauge. It's slight at best.
04-23-14, 12:04 PM
#35
LOL, I'm going to try driving like a maniac for a few days now.
Just kidding - all this is quite interesting, giving me more techniques to try.
I don't think the EV mode will drain the batteries that quickly. At times I've run my vehicle in ECO mode, showing the electric motor(s) running only (no ICE) for quite a ways - far more than 1/4 mile. This is usually at `35 - 40 mph, so it is not freeway driving. The battery does not go down that much, but ultimately the ICE will have to recharge it usually. Sometimes I'm lucky and there is a downhill that helps out.
I've also run it in EV mode for quite a ways - I think I've had it cut out at the 1/4 mile distance twice now. That is a rare day though simply because of all our stop lights in town.
Just kidding - all this is quite interesting, giving me more techniques to try.I don't think the EV mode will drain the batteries that quickly. At times I've run my vehicle in ECO mode, showing the electric motor(s) running only (no ICE) for quite a ways - far more than 1/4 mile. This is usually at `35 - 40 mph, so it is not freeway driving. The battery does not go down that much, but ultimately the ICE will have to recharge it usually. Sometimes I'm lucky and there is a downhill that helps out.
I've also run it in EV mode for quite a ways - I think I've had it cut out at the 1/4 mile distance twice now. That is a rare day though simply because of all our stop lights in town.
04-23-14, 05:09 PM
#36
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The reason that EV will only last a quarter of a mile is because it takes a lot of energy to make a vehicle move from a standstill than it does to keep a vehicle in motion. At 25 mph, the cars weight is working against it.
I only use EV mode when I have just finished parking and need to move the vehicle or turn the steering wheel
I only use EV mode when I have just finished parking and need to move the vehicle or turn the steering wheel
04-25-14, 10:05 AM
#37
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) It's amazing how much space you can create around you when you don't try to "keep up with traffic." And I managed to make the round trip without dropping the car's computed average mpg below 31.1. But that's not real; I recently calculated that the car's computer overstates average mpg by about 4 percent.Steve
04-25-14, 04:01 PM
#38
No, I don't play soccer!
Steve, great to hear you're behind the wheel again 
I hope you continue to get better.
Earlier this week, a friend and I went to the New York International Auto Show. We looked at the 2015 Camry (she's had three - an '88, an '04 and now an '11). She wanted to check out the Corolla since it's similar in size to her '88 Camry. Size is important, she's on the petite side. I was shocked to learn her '11 Camry is almost the same size as the RXh
Anyway, so why am I talking about this. My friend has been window shopping the Prius for years but is seriously considering getting one now. We had a chance to look at them while we were at the show. The Toyota person was telling us the Prius can stay in EV mode at much higher speeds and for several miles. I just wonder where this would be beneficial. Evading police silently 
Ninja Prius is what he said. I call it stealth mode. Why is everybody interested in sneaking around 
Anyway, I find limited use for it too. That's not to say I don't appreciate all the technology behind it. Maybe I'll try using it more and see.
I hope you continue to get better.Earlier this week, a friend and I went to the New York International Auto Show. We looked at the 2015 Camry (she's had three - an '88, an '04 and now an '11). She wanted to check out the Corolla since it's similar in size to her '88 Camry. Size is important, she's on the petite side. I was shocked to learn her '11 Camry is almost the same size as the RXh
Anyway, so why am I talking about this. My friend has been window shopping the Prius for years but is seriously considering getting one now. We had a chance to look at them while we were at the show. The Toyota person was telling us the Prius can stay in EV mode at much higher speeds and for several miles. I just wonder where this would be beneficial. Evading police silently Ninja Prius is what he said. I call it stealth mode. Why is everybody interested in sneaking around Anyway, I find limited use for it too. That's not to say I don't appreciate all the technology behind it. Maybe I'll try using it more and see.
05-03-14, 02:50 PM
#39
Driver School Candidate
I have two hybrid Lexuses, a RX450h an a CT200h. Both 2011 models, in Norway, Europe. The 200 has a dedicated EV button in the center console, the RX don't. In the RX I have to enter the steering wheel menu to hit EV mode. Om both cars, I am able to engage EV mode on cold engine, doing this immideately after pushing the Power on button. I find this feature very useful, for example when I have to move the car out of the garage to get access to any other items, or for washing it. This way, I can drive the car out, then in again, at any time, without ever starting the combustion engine. This saves me for another cold start, and a cent of fuel.
For those of You always wanting more miles or speed on EV mode, buy an electric car or a plug-in. Then You will have these advantages, and other disanvantages, for example a more expencive battery with shorter lifetime.
I really love the idea and the performance of the RX450h. It gives me all features of a V8 Crossover, but with higher MPG and less gearboxes, transaxels and noise.
For those of You always wanting more miles or speed on EV mode, buy an electric car or a plug-in. Then You will have these advantages, and other disanvantages, for example a more expencive battery with shorter lifetime.
I really love the idea and the performance of the RX450h. It gives me all features of a V8 Crossover, but with higher MPG and less gearboxes, transaxels and noise.
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