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2020 Ioniq Blue trim HEV
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Discussion Starter #1
Slightly older :whistle: new owner of a 2020 Ioniq Blue, been involved with all levels of cars my entire life but never had a hybrid before. I’ve worked in mechanical/electrical settings for years and mostly understand the hybrid concept but looking for more detailed information about this particular platform to gain what can’t be found in a owners manual. Who knows as I pickup details from some here and blend it with my background I may be able to offer others help in the future.
 

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Red 2019 Ioniq 38 Premium EV
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Well, I think you'll find the hybrid a pretty simple machine, does energy recovery when braking, and gives that back to you when accelerating again. You still have all the 6-speed/whatever gearbox, clutch(es), etc of conventional ICE cars. If you do a lot of long distance motorway cruising at steady speed, that hybrid addition isn't going to fo much for you. But you do have excellent aerodynamics to help the mpgs!

The plugin PHEV, providing you do actually plug it in (some here in UK just drive on petrol everywhere, using the high mpg claims as a tax-dodge or clean-air-region dodge etc!) does let you genuinely reduce your consumption of fossil fuels significantly. Yo can think of that as giving you a super-clean & quiet gallon of petrol each time you recharge. The car is still very noticeably a petrol-based beast.

But the PHEV version doesn't compare with the tech in the Chevy Volt Mk1 which predates it! Read up about that if you want to find out how a PHEV should be engineered. All others are simply a petrol-based ICE car with electrics added on, so the Hyundai PHEV, being a typical PHEV design, is like this, and whenever you want full power acceleration the ICE has to fire up. Volt isn't like that! It's a proper EV underneath, with 150 hp Electric motor drive, and then there's a modest petrol engine bolted (75 hp appx) on to give the super-long-range capability. Which is why the Volt tech is still the best PHEV out there, bar none. So sad GM dropped it.

Then you advance to full BEV, and here the Hyundai Ioniq is excellent. But a long way from the entry-level Hybrid!
 

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2020 Ioniq Blue trim HEV
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Discussion Starter #3
Well, I think you'll find the hybrid a pretty simple machine, does energy recovery when braking, and gives that back to you when accelerating again. You still have all the 6-speed/whatever gearbox, clutch(es), etc of conventional ICE cars. If you do a lot of long distance motorway cruising at steady speed, that hybris addition isn't going to fo much for you. But yo do have excellent aerodynamics to help the mpgs!

The plugin PHEV, providing you do actually plug it in (some here in UK just drive on petrol everywhere, using the high mpg claims as a tax-dodge or clean-air-region dodge etc!) does let you genuinely reduce your consumption of fossil fuels significantly. Yo can thaink of that as giving you a super-clean & quiet gallon of petrol each time you recharge. The car is still very noticeably a petrol-based beast.

But the PHEV version doesn't compare with the tech in the Chevy Volt Mk1 which predates it! Read up about that if you want to find out how a PHEV should be engineered. All others are simply a petrol-based ICE car with electrics added on, so the Hyundai PHEV, being a typical PHEV design, is like this, and whenever you want full power acceleration the ICE has to fire up. Volt isn't like that! It's a proper EV underneath, with 150 hp Electric motor drive, and then there's a modest petrol engine bolted (75 hp appx) on to give the super-long-range capability. Which is why the Volt tech is still the best PHEV out there, bar none. So sad GM dropped it.

Then you advance to full BEV, and here the Hyundai Ioniq is excellent. But a long way from the entry-level Hybrid!
Thanks for the reply and my Blue trim does have the DCT (dual clutch 6-speed) gearbox. The Blue trim is the basic HEV hybrid, we wanted the PHEV but because of some weird politics here in USA, the individual states have to approve sale of PHEV in that state and only twelve states has done that to this point and ours is not one of them. That along with not yet being comfortable with EV's because of presently limited charging stations in USA and the charging wait period involved when away from home made us settle on basic HEV.

Weird thing I found with the Ioniq HEV trim levels was the Blue trim without regenerative braking listed had higher mpg rating than the higher level trims SE, SEL and Limited with the regenerative braking listed :confused:.
 

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2019 PHEV Ultimate
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Weird thing I found with the Ioniq HEV trim levels was the Blue trim without regenerative braking listed had higher mpg rating than the higher level trims SE, SEL and Limited with the regenerative braking listed :confused:.
The problem here is the inaccurate (though common) use of the term regen for what's more accurately described as one pedal driving. All of the trim levels use regenerative braking (feeding power back into the batteries from the electric drive motor) to maximum effect when pressing the brake pedal, but only the higher trims have adjustable levels that set how much of it is used automatically when you lift your foot off the gas pedal.

The blue trim has the highest mpg rating because it weighs the least, and also has narrower tires on smaller diameter rims (taller sidewalls) which helps lower the rolling resistance.

Edit to add: Also, congratulations on your new car and welcome to the forum!
 

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2020 Ioniq Blue trim HEV
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Discussion Starter #5
...........but only the higher trims have adjustable levels that set how much of it is used automatically when you lift your foot off the gas pedal.

The blue trim has the highest mpg rating because it weighs the least, and also has narrower tires on smaller diameter rims (taller sidewalls) which helps lower the rolling resistance.
Thanks for the welcome KevinT and clearing up the regenerative which makes sense now as you explained above. (y)
 

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It's not quite true that the advantages of a hybrid go away when you drive mostly on the highway. Instead of an Otto Cycle ICE, the Ioniq uses an Atkinson Cycle engine so it is thermodyamically more efficient. Through valve timing, the power stroke is greater than the intake stroke so more of the energy from the gas combustion goes into moving the car. The down side is that the Atkinson Cycle does not have very high torque, but the electric motor in the Ioniq takes care of that. When you're cruising, there is more than enough torque for you to drive the car, but if you need to accelerate or go up hill, the electric motor can make up for the shortfall. You have a higher mileage ICE engine that has an electric boost for times when you need it.
 

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Discussion Starter #7
.........the Ioniq uses an Atkinson Cycle engine so it is thermodyamically more efficient......... You have a higher mileage ICE engine that has an electric boost for times when you need it.
Thanks 8AA, but little confused about. You saying the Ioniq uses an Atkinson Cycle engine so it is thermodyamically more efficient, but last sentence says I have higher mileage ICE engine.:unsure:
 

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ICE nearly stands for Internal Combustion Engine.

Otto, Atkinson, Wankel and even the 2 stroke motor in a lawn mower are all ICE engines.
 
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Discussion Starter #9
ICE nearly stands for Internal Combustion Engine.

Otto, Atkinson, Wankel and even the 2 stroke motor in a lawn mower are all ICE engines.
Thanks Steel188, I'm VERY familiar with internal combustion engines since I think I've worked on every type made 2 and 4 stroke. I'm just not familiar with the "Otto Cycle" name/term :unsure: before the ICE abbreviation and made me think it meant something different.
 

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Otto cycle = Diesel cycle. Regardless of petrol inefficiency at tickover thx to throttling issues, the compression-ignition cycles are fundamentally more efficient than the more gentle progressive-combustion traditional petrol ones, as with Diesel, the entire fuel gets combusted at the maximum pressure stage of the cycle. In the petrol cycle, only a tiny amount of the fuel is burnt at the very start (ignition) instant, and a lot is burnt after the piston has moved down the cylinder. This is fundamentally a less-efficient moment to burn that fuel compared to having done it all at the instant of combustion.
It also helps the diesel figures that there's more energy in a gallon of that than there is in petrol, but again this is a different issue. I suspect that some of the newest compression-ignition petrol engine may be using a cycle that's much closer to the Otto one, with higher compression ratios which improves theotretical efficiency, but also measn the burning is at a higher temperature so you start to burn Nitrogen as well as the fuel, which is a bad thing. I rather hope these Atkinson cycle engines in Phevs aren't going in that direction, but staying with modest compression rations in region of 10:1 .
 

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Discussion Starter #12
........ In the petrol cycle, only a tiny amount of the fuel is burnt at the very start (ignition) instant, and a lot is burnt after the piston has moved down the cylinder. This is fundamentally a less-efficient moment to burn that fuel compared to having done it all at the instant of combustion.
I have a little different take on this statement, gas/petrol engines consumes all fuel at point of detonation without expanding and burning after that point. The exception is when using some modified fuels, like nitro methane which I’ve ran in few of my race cars including one in my avatar.
Nitro burns slower and when ignited it rapidly expands/burns during the entire piston movement in the down movement of piston (pushing it downward), similar as you describe the gas engine doing above. Because of the rapid expansion/burning and in racing engines where an excessive volume of fuel supplied, the only way to stop the downward force on piston was to open the exhaust valve to relieve the downward force, which can be seen a night with flames exiting exhaust pipes. Because of engine/driver position and four upward turned pipes mid way on each side of car, when racing at night I could see the flames shooting upward outside of both side windows.
 

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While diesels use the Otto Cycle, they aren't the only internal combustion engines to use it. The Otto Cycle is a four-stroke cycle (intake, compression, power, exhaust) with the piston stroke being the same in each revolution of the crankshaft. The Atkinson Cycle intended to improve the efficiency of the Otto Cycle by mechanically increasing the power stroke allowing more of the energy of combustion to be utilized. It was a fairly complex affair to allow the piston to move one distance for the compression stroke, but then move a greater distance for the power stroke. There were some limitations on engine speed because of the mechanical complexity, and while it did improve efficiency, it never gained popularity.

A renewed interest in the Atkinson Cycle happened when variable valve timing was developed. Instead of having a mechanism to change the stroke of the piston, the intake valve could be left open at the start of the compression stroke and effectively reduce the volume of that stroke. For the power stroke, the valves opened and closed normally creating a longer effective stroke and allowing more of the heat and pressure from combustion to be utilized. The reason that all internal combustion engines aren't using the Atkinson Cycle is that while the efficiency is higher, the torque curve is rather flat and would be too anemic for most drivers.

Since the valve timing can be adjusted on the fly, an internal combustion engine could operate as an Otto Cycle when it needed power, but could shift to an Atkinson Cycle when the torque requirements were not as great. Some manufacturers have already tried doing this. However, whether it is a HEV or a PHEV, the electric motor can utilized to add the necessary boost when you need to accelerate or go up hill. This isn't a new concept, Toyota has been using an Atkinson Cycle engine in it's Prius since 1997.
 

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Discussion Starter #14
Instead of having a mechanism to change the stroke of the piston, the intake valve could be left open at the start of the compression stroke and effectively reduce the volume of that stroke
Great explanation 8AA and thanks to you I had already looked up Atkinson Cycle difference than the normal ICE of holding intake open short period at begging of compression stroke. Since that has been a bad thing for years in ICE’s causing reduced vacuum in intake manifold of non-pressurized engines (turbo/blown), I will be looking into the process more and have already started analyzing the concept already (normal for me).
 

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I think that when Mazda used the Atkinson Cycle, it did (or does) have a turbo or some other method to pressurize the intake. I don't know of any problems that Toyota has had with the engine, and I've been driving the same Prius for almost 17 years.
 

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Discussion Starter #16 (Edited)
I will be looking into the process more and have already started analyzing the concept already (normal for me).
I don't know of any problems that Toyota has had with the engine, and I've been driving the same Prius for almost 17 years.
Hi 8AA, been searching and analyzing the Atkinson Cycle concept as to vacuum lost with the intake open for short period with piston moving upward on compression stroke. As I suspected there is some vacuum lost and even pulsating in NA (naturally aspirated) engines. I’ve learnt that this has been minimized at least by Toyota, by use of baffling in runners to each cylinder and a surge chamber built into bottom portion of intake manifold, I suspect Hyundai uses the same things to minimize vacuum loss. Not sure if your Prius is new enough to have these incorporated into your intake manifold.:unsure:

I had already notice the long individual cylinder tubes built into the intake manifold of the Hyundai engine, which I immediately knew was to increase low/mid range RPM torque (past experience with racing engines), but didn’t suspect it was to help with minimizing the torque lost by holding the intake open at start on compression stroke. All those modifications to the intake manifold to minimize the torque loss along with the electric motor, VVT (that you’ve already commented on), direct injection and computer systems of course, is what has allowed all this to come together.
 

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I don't remember the specifics, but I know that there was some sort of modification to the intake manifold in the Prius from the beginning to improve the performance. The direct injection also helped, but the real key was the computer system, otherwise the Hybrid Synergy Drive (the power split device) would never have been possible.
 
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