Hybrid-Electric Vehicle Energy Monitor

Hybrid-Electric Vehicle Energy Monitor


this is a demonstration of the hybrid electric 2008 Highlander energy monitor on the instrument panel on the navigation display you can see here that we’ve got the internal combustion 3.3 liter engine has shown the front trans axle which actually has two electric motors in it but there’s one motor the mg 2 motor that propels the vehicle down the road either by itself or with the assistance of the engine and then there’s a rear electric motor since this is an all-wheel drive SUV that will supply power to the rear wheels when needed when the front wheels are detected that they’re about to slip or are slipping it also supplies power to the rear wheels when you’re taking off from a stop sign every single time from about zero miles per hour two three four five miles per hour and then it does it even more if it detects the outside temperature is is cold enough for water to freeze and have ice on the road so that’s that’s pretty intuitive then we have a battery meter right here these blue bars can turn green when they I mean the battery level gets higher and they can turn purple when it gets the battery level gets low is this kind of an intermediate level right now typically we want the battery to stay between 20% of charge and 80% of charge this is a nickel metal hydride battery and the reason for that is most of these batteries have about a 1,000 cycle life which means if you ran them from completely dead to completely recharged 1,000 times the battery’s useful life would be over and if you did that once a day you could see that or calculate that it would be close to three years and you’d be out of battery life well these batteries are lasting a lot longer than three years it’s a matter of fact they have a 10-year warranty 10 year 100,000 mile warranty on them so the hybrid electric control system the battery controller tries to keep the battery from going that low and from well from going below or even near 20% or and especially below 20% and from going above 80% so if they can do that if you can do that then the battery life will be longer and have more cycles since we’re not doing a full cycle little bit will be partial cycles I’m gonna back the vehicle out of my garage I’m on my way to work the navigation display turns into the backup camera as I back out of the or any time as I back up and then when I go forward I can go back to the hybrid energy meter or the map system okay I’m stopped on a main road in my neighborhood and I’m gonna start to accelerate you’ll notice these little grey what look like pathways are their energy pathways and as I start to accelerate here you can see that we have energy leaving the battery feeding the front motor that drives the front wheels leaving and going to the rear motor which drives the rear wheels I am doing maybe five six almost ten miles an hour you can see that the power to the rear wheels is no longer determined necessary and we’re just in a front wheel drive mode right now the internal combustion engine is off there’s no power being delivered out of it and I can drive on electric only power mode as long as there’s some battery life the internal combustion engine just kicked in as you can see in the orange bars there to help accelerate if I step on the accelerator pedal harder than a certain rate the battery could provide then the internal combustion engine starts up and helps provide additional acceleration but also this is a little bit cooler over morning it’s in the low 60s outside air temperature and first thing in the morning typically the engine will come on anyway to warm up the catalytic converter and the engine coolant so that the rest of the time during the drive it can go into the idle stop mode whenever we’re to stop light or a stop sign I’ve got a Garmin GPS system that I have in the same vehicle that I use not for navigation but because it has a feature that keeps track of how much time I’ve been stopped versus how much time I’ve been traveling with the ignition on and I’ve done this for a couple of years now keeping track of this but typically what I’ve seen is for about every twenty five hundred miles of driving I have pretty close to twenty two hours of stopped time I’m gonna stop sign now accelerate again going on to a main load we just came out of a neighborhood with 25 mile an hour speed limits going up to 40 miles an hour anyways we can lost my train of thought there but I think I was talking about electric mode and the engine warming up but once the oh yeah the Garmin GPS I had the keeping track at the time stopped versus the time driving in and within twenty five hundred miles of driving I had about 22 hours of stop time that this engine would be off when it’s off it’s not burning fuel it’s not polluting the atmosphere this engine at idle typically goes through a little less than a half gallon per hour I’ve got a another I’ve got an iphone application called – command with a data link connector cable go link that I used to monitor and record fuel economy data as I Drive gives me the gallons per hour or fuel used now notice as I decelerating every time I decelerate the wheels turn the electric motors we’ve got the motor in the rear that’s called M G our motor generator rear and then we’ve got the M mg one and two are up frontier mg – which propels the vehicle is what we’re powered with right now you can see we have power just coming out of the battery and supplying the Wills but if I accelerate more rapidly right there then the engine kicks annan and assists there is a speed however and now I’m pulling up to a stoplight just about to the freeway where we can get up to freeway speeds and see what’s going on but there is a speed a maximum speed at which we can drive on electric power only and on a fully charged battery proper outside temperature engine warmed up that maximum speed is about 37 to 40 miles an hour somewhere in that range it doesn’t happen very often quite often I can be on electric power only up to about 3035 miles an hour but if I go any higher any higher vehicle speed than that then the engine kicks on and the engine has to kick on because the planetary gearset that these two front electric motors hooked to and the internal combustion engine hopes to if we spun the motor the mg2 motor any faster with it with the engine off it forces the mg 1 which is the generator motor 2 to spend too fast so by having the engine come on it helps slow down the mg 1 generator so we don’t over speed I’m accelerating getting on the freeway on-ramp getting up to 65 miles an hour okay you’re up to sixty-five and what I found in driving this for the last three years every day is that the faster you go the worse fuel economy you’re going to the lower vehicle speeds the battery is able to contribute power to the mg2 motor along with the power from the internal combustion engine to propel the vehicle but the faster you go the less effective that becomes and at the higher speed 75 miles an hour 85 or 80 miles an hour we have some speed limits around here of 80 and 75 it can’t contribute as much so the best fuel economy that I’ve recorded in this 56 hundred pound SUV that all seven passengers is at 55 miles an hour with the cruise control on because the Pierce control makes a whole bunch of difference in fuel economy we’ve got as high as 38 miles to gallon driving at 55 miles an hour but if you’ve ever driven on freeways you know you can’t drive 55 miles an hour back in traffic up everybody honk but there are been construction zones where we had to drive 55 for extended distances be in the high 30s the entire time that at that speed then at 65 miles an hour which is what I’m driving now depending on the outside temperature in the battery temperature because cold batteries don’t operate as well the fuel economy is around 28 to 30 miles per gallon at 75 miles an hour it was clear down to 26 or so you drive really fast bastard go clear down to 22 or so you can see here on the screen that at 65 miles an hour when the battery is able it supplies power to the model when it’s not able the engine is supplying the power through the mg one generator to supply current to the mg two motor the vehicle and anything extra goes back to the battery recharge the battery now these these batteries of DC book DC volt batteries the particular battery in this 2008 Highlander Hybrid is a 288 volt DC battle these motors were a non three-phase AC voltage which can go as high as 650 volts so obviously we’ve got DC into AC to drive these motors and not just AC but three phases of AC because these are synchronous [Music] Motors there’s a part out underneath the hood called the converter converter assembly as we accelerate it takes DC voltage and current from the battery inverts it into AC that drives motors but when we decelerate takes that AC and rectifies it back to DC just like an alternator hood and anybody’s father for automobile and recharges the battery with that so we can invert DC into AC to drive the motors rectify AC into DC to recharge the now this is 288 volt battery as I’ve mentioned this vehicle and most time most hybrids still have the 12-volt battery and so there’s also a DC to DC converter involved in this system that takes the 288 volts DC and steps it down to 14 volts to supply power to keep the 12-volt battery charged this vehicle does not have an alternator it does not have a starter motor is relying on this DC to DC conversion and we step it down it’s called the PUC converter when we step the voltage up it’s called a boost we do both this also has an electric air-conditioning compressor with electric water pumps electric power steering and these these all run on various voltages DC or AC that is all controlled as part of the hybrid electric system so we’re few miles into the my drive to the University this morning you can see even a freeway speeds there are times when the electric or supplied mainly by the not that often but typically on my drives to work from my house every day I have some stop-and-go city driving and have some freeway driving the overall trip is 17 miles and in that trip I typically average 26 to 27 miles to gallon in this issue which is pretty good for a seven-passenger 5,600 pound there should be even get close to them one of the things that helps this vehicle get good fuel economy is its aerodynamics this is certainly not nice sleek vehicle as far as aerodynamics are concerned but it’s not really bad either this vehicle has an aerodynamic coefficient of drag of 0.35 the Toyota Prius which has the lowest coefficient of drag of any vehicle on the road today is point two-five the Chevrolet Bowles is point two six Toyota Camry was point two seven most SUVs your 0.35 or higher and what that what those numbers mean is as compared to a cube the square cube driving down the road the cube has it is assigned a number of one point zero so if you can drive down the road with less aerodynamic drag than a cube now I’m decelerating here you can see this charge going on so if you have less aerodynamic drag than a cube then you have a number the coefficient of drag less than one point zero and this is of 0.35 like I said the Prius is a 0.25 if you have a number higher than 1.0 then you have more wind resistance than a cube driving either you might think well what what vehicle is that and it would be a motorcycle with the rider sitting up on the motorcycle the rider kind of acts as a parachute and causes the extreme amounts of drag as you drive a motorcycle and that’s without a win fairing on the front of the motorcycle just to plain motor so so we’re going down a kind of a long steep hill here going down the hill instead of just coasting down the hill like most vehicles do the kinetic energy of the vehicle moving in a hybrid vehicle is allowing the wheels to turn the this very same electric motors that propel the vehicle it turns those into generators and we take that AC voltage just like in an alternator and rectify it into DC and send it back to the battery for charging also whenever I step on the brakes we have what’s called regenerative braking which network drive next a speed here for a little bit in regenerative braking we use the electric motors to actually break the vehicle to slow the vehicle down by turning the charge rate up if you turn the charge rate up it puts quite a load on those motors and makes them difficult to turn and so by doing that we can vary the charge rate which varies the braking force now this does not these vehicles do not stop on the regenerative braking only they still have a hydraulic brake system that is blended with the regenerative braking depending on your rate of deceleration so if you have if you’re in a panic stop you’re probably going to get the majority of hydraulic braking and not much regenerative braking you can see the battery level is high from coming down which in the green zone but if you’re back to breaking if you’re breaking slowly just a gradual break then the regenerative braking does the majority of the braking but it’s still blended a little bit with hydraulics the regenerative braking does not work at really low vehicle speeds so like three miles an hour and below it’s hydraulic braking that’s going to be a stop of the vehicle okay now we’re driving a straight flat road here for a little bit move to going too fast but slow down the speed limits only 35 here the main town Weber State University is located and now I’m doing about 3035 miles an hour the brake pads this this vehicle has about a little over 50,000 miles on the disc brake pads on this vehicle I looked at about 5,000 miles ago when I did a alignment on this before long trip and they looked brand new it’s it’s amazing how long the brake pads last on a hybrid electric vehicle because of this regenerative braking it’s very impressive so hybrids hybrid vehicles cost more than than other vehicles for sure but you need to decide whether it will pay pay for itself in its additional cost versus what vehicle you’ve come out of for example I came out of a 1999 Dodge Durango three years ago when I bought this thing in 2008 when fuel prices around here hit four dollars and 35 cents a gallon my 1999 dodge durango had a 25 gallon fuel tank and to make this same drive every day like I’m doing right now I would go through almost an entire tank per week so over a hundred dollars a week in fuel costs I was paying four to five hundred dollars a month in fuel my Durango was paid for but at 10 to 12 miles to gallon it was still costing me a lot of money and it was old and worn out it was probably time for another vehicle anyway but when I switched to this vehicle the hybrid hot Highlander cost about $3,000 more 3500 more than a non Heiser not I’m sorry non-hybrid Islander and I get I’m talking the fully loaded ones ones with all the options you can get Highlanders for a lot less than what a hybrid Highlander would cost but I wanted the navigation system and the rear climate control and the leather seats DVD system and all that in here so a fully loaded Highlander that’s not Hybrid was very close $3,500 or so to the cost of a fully loaded Highlander Hybrid so for me it was only $3500 difference from one to the other will the fuel economy difference between the standard hybrid I’m sorry the standard Highlander and the hybrid Highlander was was was pretty good but for me the big difference was the fuel economy difference coming out of my Durango vs. this Highlander Hybrid the fuel economy is doubled and so for me in fuel costs it paid for itself within the first year now I still have a higher priced car that I had to pay for but I was gonna buy a car anyway so for me it paid off if you’re coming out of a vehicle that gets really good gas mileage anyway and it’s not a hybrid and you want to pay more money to get a hybrid to get a tiny bit better fuel economy your payoff may take a lot longer to do and it may not be worth it to you however there are other advantages to having a hybrid besides financials over the long run in fuel savings and brake pad savings the maintenance costs on these hybrids aren’t any higher than any other vehicle other than the tires I found that the low-rolling-resistance tires are considerably more expensive than the standard tires that you you can get out there but you get better fuel economy with them also so I’m not sure how you calculate that exactly but it still has standard oil changes there’s nothing unique about the hybrid system that needs additional service it has its own cooling system but it uses the same coolant that is used in the engine so there’s I haven’t seen any additional costs with having the hybrid vehicle well we just about to work now and this has been a demonstration of the hybrid energy monitor it’s a very useful thing to get the idea of what’s going on with the hybrid system there’s a consumption button right here if I push that it shows us a bar graph of my drive it took about 27 minutes 26 minutes to get here each one of these bars represents one minute of driving and the fuel economy is listed here in the x-axis it goes up to 60 miles an hour as the macker miles per gallon is the maximum we’ve got 20 and 40 and then that up to 30 minutes of driving it’s the last 30 minutes of driving these little green cars that are here represent 50 watt hours of power regenerated from going down hills or regenerative braking so we’ve created our own power through the kinetic energy of the vehicle moving and this can help you fine-tune your driving to get better fuel economy so this has been a demonstration of the hybrid energy law monitor on a 2008 Toyota Highlander Hybrid


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