Thackeray

My guess is that one of the key limiting factors is the size of the battery. The eCVT transmission (power split device) splits the power output from the engine between the road wheels and motor-generator 1 (MG1). I don't know what the split is but on the first Prius I think it was 78/22. So let's say around 3/4 of the engine's 286 bhp is directed straight to the road wheels. The remaining 1/4 drives MG1, which generates a bit less (because of efficiency losses) than 1/4 of the engine's output. The generated electricity then drives MG2 (more power loss) which is connected to the road wheels. As for the electric motors, I've never seen it spelled out anywhere but my guess is that the quoted electric motor capacity is for the two motors combined. In the above scenario, MG1 is fully in use, transferring the engine's power to MG2, so none of its electric motor capacity bhp can be used while it's in generation mode. But some of the electric motor capacity (perhaps the larger part provided by MG2) can still be brought into play by feeding more electricity to MG2. Let's say MG2 has half of the quoted 197 bhp or around 100 bhp. This is available to add to the power (direct and indirect) from the petrol engine. But this power has to come from the battery. I have no idea whether the battery can add enough electricity to produce 100 bhp from MG2. But I would suspect not and certainly not for very long - only a few seconds probably. If the maximum total output is 338 bhp, with 286 bhp coming from the petrol engine, that suggests that the battery can only provide enough for around 50 bhp from the electric motors, even though they are quoted as having a capacity of 197 bhp. So I would guess that the limit on total bhp is structural to some extent and in addition that there are software limits to the rest of the available power to protect the battery and to protect the electric motors, which would be damaged if they could spin beyond certain limits.

I had Michelin Cross-Climate on the car when I bought it. The ones on the rear wore from 5mm to 3mm in 15,000 miles. The ones on the front from 6mm to 5mm on one side and to 4mm on the other. That's around 2mm all round for 15,000 miles, or maybe a bit better for the front. So if new tyres start at 7mm and they're changed at 3mm, they should last around 30,000 miles if the rate of wear is consistent through the tyre's life. I thought this was pretty good and I replaced them with the next generation of Cross-Climate. These are 17" wheels, so maybe larger wheels will last longer. I can't yet tell if the new Cross-Climates are better or worse for the rate of wear.

When I use Hybrid Assistant or Tire Assistant they both connect automatically. I can't remember for certain but I think this is because on the first use I paired my phlone with the Carista dongle. After that is done once, I imagine any app on the phone that uses data from the dongle will work without any need for further setting up. The Tire Assistant is handy for checking pressures without getting your hands dirty. But I don't think it allows you to change the sensor ID like the Carista app. But you used to get a month's free use of the Carista app. If that's still the case you can use facilities like that for a while without paying.

One thing to bear in mind is that it draws power whenever it's plugged in. I once ran my 12v battery down to 11.4v when I forgot to take out the Carista adapter and left the car unused for two or three days. Fortunately, the car would still start. On the plus side, when you get yours you can also use it with the Hybrid Assistant app, which is really great for getting to know how the hybrid system works. Maybe this isn't your first hybrid, but if it is Hybrid Assistant can tell you more than you ever wanted to know about what the hybrid system is doing. It's a free app, developed in Italy by hybrid enthusiasts. Here's a link to their webpage. https://hybridassistant.blogspot.com/p/screenshots.html

Unlike a conventional car with an alternator, driving the car makes no difference to the rate of charge of the 12v battery. As long as the car is in the Ready state, there's a feed of around 14.5v to the 12v battery from the high voltage battery whether the engine is running or not. If you don't feel like going for a drive, it will use less petrol just keeping the car stationary. The engine will start from time to time when the high voltage battery needs topping up.

If your car is from 2014, you might be affected by the issue described in the following thread. If you are, the best option may be to get a dealer to change the battery to avoid any problems. https://www.lexusownersclub.co.uk/forum/topic/126933-screen-black-after-battery-change/#comments

The CVT video above is a modern version of how the DAF CVT worked. Here's another video about how the Toyota/Lexus eCVT works. No rubber or flexible steel bands. And bear in mind that the drive chain shown at the end of the animation doesn't exist on later models of the Prius or on the Lexus hybrid drive. Incidentally, one of the earliest patents for this kind of system was in 1908 by John Thomas, living at The Vicarage, Holywell, Flint.

Yes, exactly. The link still works as this is just standard http (hypertext transfer protocol). It's the Adobe Flash bit at the bottom of the page that doesn't work now. I've read that Adobe Flash animations can be converted into html5 using Adobe Animate but my computer isn't powerful enough to install this. If anyone has a copy of Adobe Animate installed, maybe they could convert the Flash animation into a file that would work properly.

It's at this link but as expected the Adobe Flash bit doesn't work now after Adobe withdrew support for Flash. It's possible that some people may still have an old version of Flash on their computer and as long as they don't update it, it may still work. It still has a good simple graphic at the top that shows the principle of the planetary gearset. Although the transmission is complex electronically and wouldn't be possible without computers, mechanically it's a very simple and elegant device with hardly anything to go wrong, compared with traditional gearboxes with several actual gearsets. It's like the DAF system in that it produces variable ratios without actually changing the gears in use. But the DAF system used rubber bands to give varying ratios from cone shaped elements in the gearbox. Mercedes and Toyota and no doubt others use the same principle in their CVT gearboxes but the drive band is made up of steel links instead of rubber. The Toyota/Lexus "power split device" or "eCVT" is a much more elegant concept and uses a permanently meshed planetary gearset, rather than variable ratios from the rubber/steel drive band. It's a pity that the best graphic has now disappeared from the internet but here's a presentation of an actual transmission which shows how few cogs there are compared with a traditional gearbox, manual or automatic. So it never actually changes gear - the computer just varies the speeds of the various power sources.

I expect it could be 11.95 unless you have reasons to distrust the meter. It will rise quite quickly while in Ready state but an hour or so after turning the car off I doubt it will still be at 12.36. More likely 12.2-12.3. And tomorrow, lower again. The 14.5 figure isn't the battery voltage. It's the voltage of the charging current coming from the hybrid battery via the converter/inverter. As soon as you turn off the car the 12v battery will be showing the lower figure again.

The lowest I've seen (and someone else reported this in another thread) is that it will successfully get into Ready state from 11.4v. I suspect it will go even lower but I haven't heard of any reported cases. While the car is in Ready state the charging voltage from the DC/DC inverter will vary depending on the temperature of the battery and possibly the state of charge of the 12v battery. When the car first starts up I've seen around 13.9v initially, rising to around 14.4v as the car warms up.

Many thanks for that. I hadn't realised the rear motor was also a generator. So there are three motor/generators - MG1, MG2 and MGR. I've now found a detailed description of this setup, with the P310 transmission on the front and the Q211 on the rear. This video goes into the details of how it works.

I'm not familiar with the setup of the RX400h transmission. I thought the transmission drove the front wheels so the regenerative braking would be on the front wheels. Am I right in thinking there's another electric motor on the rear wheel? I had assumed this was just a motor rather than a generator. Does this act as a generator too when braking, so that the mechanical brakes on the rear also don't have to operate so much? Apologies if I've misunderstood the setup on this car.

Interesting to hear this idea. What's the reasoning behind it?

It used to be possible to have temporary licence plates so that you could drive a new car back to the UK from a dealer in Europe. I've done this a couple of times, once from Germany, once from Belgium, with temporary plates from each country. You could also get temporary insurance, for a few days or enough to get the car back. There may be pitfalls in this, though. If it's registered in France, are you considered to be importing it in to Britain? Perhaps not if it can be dual registered in Britain too.

That's interesting. 6.7 l/100km (42 mpg) is not far off a typical year-round average of around 6.4-6.5 (44 mpg). When the weather starts to get hot, maybe you can do an update on the effect on fuel consumption. In the UK, particularly when it's mild weather, you can hear the electric driven compressor running in short spurts. Maybe it will run continuously in genuinely hot weather. Even if the outside temperature isn't that high (30?) the intensity of the sun on a metal cabin is probably going to need a lot of cooling!

Interesting to read this. The experience I've had with my car is different. On previous cars, re-engaging cruise control after slowing down used to bring aggressive acceleration back up to the cruising speed - much more aggressive than my usual driving style. I sometimes felt like apologising to passengers, saying "It's not me accelerating like this - it's the car." So I was surprised and pleased when I first discovered the behaviour of my IS300h. I was driving along a 70mph dual carriageway interrupted by roundabouts every half mile or so. So I slowed down for the roundabout and then re-engaged cruise control at about 30mph as I left the roundabout. And instead of the aggressive acceleration I was used to from previous cars, it gently gathered speed, intelligently increasing the rate of acceleration until it reached cruising speed again. It behaved pretty much the same as I would have done if I was doing the acceleration. I was quite impressed. I wondered if it made any difference if you were in ECO or normal or Sport. But I didn't notice any difference. It's surprising that others have had a different experience. As for the fuel consumption I don't think it has anything to do with it being a hybrid. For pretty well all cars, the faster you go the less mpg you will get. Cruise control is designed to keep you going fast in circumstances when you as a driver might choose to go slower. Like going up hills, as Colin mentions. Going up a long steep hill with cruise control is often an experience of overtaking car after car, as other drivers instinctively (or perhaps unconsciously) slow down for the hill. And the faster you go, the worse mpg you will get. So cruise control isn't really an economy feature and it's no surprise that it can use more fuel in hilly terrain.

Have you taken the existing radio out? Is it difficult to remove? Might come in handy to know how to do it one day!

This is true. However, there's quite a lot of play in the parking pawl. So when the engine is running smoothly I think there is a small amount of counter-torque applied to the drive wheels by MG2 so that the transmission isn't even pushed up against the parking pawl. You can feel the transmission clunk and the car rock slightly if it does hit the parking pawl.

As I understand it, when the car is in Park, MG2 applies a small amount of counter-torque to the drive wheels to keep the car stationary. This is because the engine is applying torque to the drive wheels and the car might begin to move if nothing was done to keep the car still. So MG2 applies counter-torque to stop the car moving. If the engine is misfiring (I can't play the video to hear the sound - not sure why) then there would be spurts of engine torque to the drive wheels, countered by spurts of torque from the electric motor (MG2) to keep the car still. The effect might well be the shaking you see on the front wheels.

Have you got a link or an address for the page? I'm sure a lot of people would be interested in what your research has found.

Isn't this a problem that front-wheel drive cars can have? You can hear a clicking noise from the constant velocity joints as you steer. The new ES is front-wheel drive but the IS300h is rear wheel drive. There are a lot of threads about tyres skipping on full lock when the weather is cold. Perhaps that's what it is.

Exactly. If it's parked outside at -20C I would expect that might have an impact on the fuel consumption. But if it's inside at +10C, the car never has to cope with low temperatures as such, as it's either inside or the engine is running to keep it warm. That's why I thought it would be interesting to know if it's parked outside and still gets good mpg.

Where is the car parked overnight? Is it outside at -20C or is it in a nice comfortable garage at +10C? If the car doesn't have to go through a long warmup stage fuel consumption will be much better. In Canada, they used to have plug in heaters for the radiator to prevent freezing. Don't know if this is still the case. When you went to the supermarket there were sockets outside to plug in the heaters. And it also used to be that trucks would be kept running 24 hours a day as otherwise they wouldn't start until spring came.

Heating element might be too slow and wouldn't work for mud. A blower would be ok for newly settled snow. Volvos used to have baby wipers on the headlights, matching the grown-up wipers on the windscreen, which was very cute. But I think the best answer, especially if crowdfunding is paying, would be a chauffeur.