Honda Accord Hybrid vs. Toyota Camry Hybrid

usbseawolf2000usbseawolf2000 Member Posts: 759
edited March 2014 in Honda
Accord mild hybrid will probably be offered with a manual transmission but Camry full hybrid will offer only in electronic controlled CVT transmission. Based on that, we will probably have two different groups supporting both sides.

Full hybrid is more efficient and powerful than a mild hybrid. I will provide facts regarding those two different design with available data from the Civic Hybrid and the Prius.

There will not be a limit if Honda offer Accord hybrid coupe into the comparison but let's focus on sedan vs. sedan.

Dennis
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Comments

  • usbseawolf2000usbseawolf2000 Member Posts: 759
    Honda Civic Hybrid Internal Combustion Engine Power Curve

    image

    Prius Internal Combustion Engine Power Curve
    image

    Atkinson cycle ICE in HSD has super flat torque(blue) curve. What you don't see in that graph is engine efficiency. Atkinson cycle ICE(1,500-5,000RPM) in HSD is more efficient than Honda's Otto cycle ICE peak(at certain RPM) efficiency.

    Dennis
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    Honda Civic Hybrid
    image

    Prius 2004
    image

    This graph isn't a direct comparison because Prius graph shows speed(km/h) rather than RPM. Prius has plenty of horsepower(red curve) between 30km/h(17mph) and 90km/h(56mph). No wonder Prius is faster than 4 cylinder Camry in 30-50 mph acceleration test.

    Horsepower delivery shoots up very quickly and there are plenty of power in mid-range speed. The torque at the wheel decreases as the car gets faster. Consistent with changing into higher gear as in traditional transmission car.

    Dennis
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    Honda Civic Hybrid

    ICE + 10KW Motor/Generator + Mechanical CVT
    image

    Prius 2004

    ICE + 10KW Motor/Generator1 + Planetary ECVT + 50KW Motor/Generator2
    image

    The size seems comparable yet HSD(THSII) contains extra 295 lbs-ft torque 50KW electric motor in it as well.

    Dennis
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    Honda Civic Hybrid CVT
    Curb Weight: 2736 lbs
    City/Highway: 48 mpg / 47 mpg

    Toyota Prius ECVT
    Curb Weight: 2890 lbs
    City/Highway: 60 mpg / 51 mpg

    Prius is bigger(mid-size) and heavier yet more fuel efficient.

    Dennis
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    HSD transmission is an amazing work of art. The car is always in the top gear and lowest gear at the same time! You might be wondering how can it be? HSD can achieve this because there is only one gear ratio(permanently engaged).

    HSD power response is instantaneous, within milliseconds. No shifting, no delay, no jerking, no power fluctuation, just smooth like a jet.

    Check out how small the Power Split Device(red area between two motors) which enables ECVT in Hybrid Synergy Drive.

    image.

    Dennis
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    I might be wrong but I left very little room for someone to argue for an Accord mild hybrid IMA design.

    Dennis
  • backybacky Twin CitiesMember Posts: 18,946
    Dennis, where have you heard that Honda will offer the Accord hybrid with a stick? To my knowledge, Honda has never before offered an Accord V6 4-door sedan with a stick shift, at least in the USA. They do offer the Accord V6 coupe with a six-speed stick. Now that would be an interesting configuration for the hybrid. Anyone know if it will it be offered as a coupe? Toyota could of course offer the Solara as a hybrid; it's got the same powertrains and chassis as the Camry. But I've heard no rumors of a hybrid Solara.
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    sorry, I just assumed. I figured if they offer HCH with stick, they might offer HAH with a stick.

    Dennis
  • bamacarbamacar Member Posts: 749
    Efficiency is only one factor to be considered. I would be happy with Civic like efficiency and Accord V6 power. Honda's V6 has 240hp and is much preferred over the Toyota's 210hp. The electric is only one part of the equation. Another factor is the sportier Honda ride, and the Buick-look dash in the Camry I can do without.
  • bamacarbamacar Member Posts: 749
    I wish Honda would add the hybrid technology to the Accord 4 cylinder- manual transmission LX that would be good for me. About 190hp combined horsepower and even better efficiency than the 6 cylinders. Plus I just enjoy the manual transmission which you can forget about being an option on a Camry.
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    It's not about power but it is how you use it. Prius only has 76hp ICE and it performs better than HCH CVT with 93hp engine. Prius also weights more than HCH. How is it possible? The answer is in the electric part of the hybrid. Since hybrids do not need to plug in, all the power are coming from the ICE directly or indirectly. HSD uses 76hp ICE in a more efficient manner than IMA design.

    Dennis
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    HCH CVT Curb Weight: 2736 lbs
    HCH CVT ICE horsepower: 93 hp
    HCH CVT Weight per Power ratio: 29.4 lbs/hp

    Prius Curb Weight: 2890 lbs
    Prius ICE horsepower: 76 hp
    Prius Weight per Power ratio: 38.0 lbs/hp

    If Honda Accord Hybrid weights 3400lbs and have the same weight per power ratio as HCH, it will need 3400lbs/29.4=115.6 hp ICE.

    If Toyota Camry Hybrid weights 3500lbs and to have the same weight per power ratio as Prius, it will need 3500lbs/38.0=92.1 hp ICE.

    So, in theory, Camry Hybrid with ICE 209hp could outperform an Accord Hybrid with 270hp ICE.

    Dennis
  • bamacarbamacar Member Posts: 749
    We are comparing execution of cars with ICEs of 76hp & 93hp to one with 240hp and another one with ?hp. It is a tough sell. I understand what you are trying to do, but we will see when these cars get here. Once again it is not all about efficiency or 0-60 times. In a few years Honda and Toyota may have hybrid cars that make the present Prius look like a dinosaur.

    The Honda Insight was a great start. The first Prius blew its doors off. The HCH blew the Prius away. The second generation Prius blew the HCH away. What will Honda do next?
  • alpha01alpha01 Member Posts: 4,747
    The 210 3.0L Toyota engine is soon to be retired, with a 3.5L 225+ hp engine recently announced at TMMK for the 2006 Avalon and Camry. Camrys-all trim levels for 2005 will be offered with the 3.3L 225 hp engine, which also produces 240 foot pounds of torque @ 3600 RPM, much preferred to Honda's 212 @ 5000 RPM. Transmissions are upgraded too (but perhaps we shouldnt go down the transmission road, what with that tiny Honda recall and all...)

    ~alpha
  • bamacarbamacar Member Posts: 749
    comparisons between the latest Accord and Camry? Oh, it has been unanimous. Can you say Honda? Lets hope that Toyota can keep the sludge issue out of the hybrids or it could get ugly. Can we stick to the topic at hand instead of nonpertinent issues that try to build up Toyota- whether it be non-Accord transmissions or sludge?
  • mistermemisterme Member Posts: 407
    I wonder if Toyota will keep its customers waiting...say 6-9 months for thier Camry hybrid?

    I'm not guessing which will be the better car: I don't have any idea.

    If Honda has its Accord ready to go on the lot....
    Steve
  • lexusguylexusguy Member Posts: 6,419
    The Prius wait list wasnt something Toyota did on purpose to drum up excitement for the car. The demand for the car literally caught them completely by surprise. Theres a wait list because Toyota cant make them fast enough. Since Camry and Highlander are already well established models, with large scale prodcution in place, I wouldnt expect a shortage on the scale of the Prius
  • backybacky Twin CitiesMember Posts: 18,946
    Since Toyota will be hybridizing the 3.3L V6 for their SUVs this fall, it makes sense that is the engine that will be in the '06 Camry hybrid--keep costs down by using an existing powertrain.
  • alpha01alpha01 Member Posts: 4,747
    Dont get your panties up in a bunch, I just thought your post was a bit smarmy, so I decided to offer you some facts with regard to the Toyota 3.0L V6 engine.

    If you've EVER read anything else that I've posted, youd know that I agree the Accord is probably the most well rounded car in the segment, and that I think an EX 4 5A w/ side curtains is likely the best value for most people.

    But- significant upgrades for the 2005 Camry are in store, and the new Legacy looks like its going to steal some thunder as well.

    Happy Motoring!
    ~alpha
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    In a traditional economy car, ICE power is sacrificed for better fuel efficiency. Hybrids gives better fuel efficiency and at the same time gives better power efficiency. We all are familiar with fuel efficiency by looking at EPA numbers. Let me explain the power efficiency.

    HCH only has 93hp ICE and performs almost like EX with 127hp ICE. Therefore, IMA design gives about 36%[{(127-93)/93}*100] higher power efficiency than ICE only Civic EX.

    Prius only has 76hp ICE and Toyota would normally put 145hp engine if it were ICE only car. I got 145hp by considering size weight of Corolla and 4cyl Camry where Prius is in between them. Therefore, HSD design gives about 91% higher power efficiency than a normal ICE only car.

    Based on HSD 1.91% power efficiency value, I can estimate that 4 cylinder Camry hybrid can perform like an Accord V6 with 240hp ICE if and only if, Camry hybrid Atkinson cycle ICE outputs 126hp(240/1.91) and electric motors are proportional in power(about 96KW) of the Prius.

    This Camry hybrid Atkinson ICE with 126hp will most likely be more fuel efficient than Honda Civic EX 127hp Otto ICE. Camry hybrid with 4 cylinder engine can have performance of an Accord V6 with fuel economy of a Honda Civic! Isn't it what Honda trying to do with an Accord hybrid? Interesting...

    Dennis
  • venus537venus537 Member Posts: 1,443
    how did i guess correctly that it was you who started this topic?

    and since you started this topic you should know it's accord hybrid vs camry hybrid and not civic hybrid vs prius.

    first of all, it's an error in logic to compare these two upcoming cars based upon the HCH and prius. your assumption that the accord hybird will come with a stick is a clear example.

    you actually think their won't be any improvements and innovations to honda's IMA hybrid system with the accord. that would be like making the assumption that new prius wasn't going to have any improvements over the previous dismal model.

    and lets don't forget the accord hybrid will also have cylinder deactiviation to enhance fuel economy.

    fuel economy isn't going to be such an overriding factor with the accord hybrid as it is with the prius and HCH as power performance will also be enhanced.

    and you presenting the "facts" of both sides is sort of like rush limbaugh presenting the liberal cause. the facts aren't even known for the accord hybrid, just speculation.
  • venus537venus537 Member Posts: 1,443
    are you sure the 3.5l will be a replacement engine for the 3.0l and not just be an additional engine?

    i see the 3.5l targeted for the avalon but not replacing the 3.0l in the camry.

    what's next? the accord getting the 3.2l or 3.5l engine.
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    The data that I presented about HCH and Prius were indeed facts. The comparisons between IMA and HSD design can be related to make an educated guess about Accord hybrid and Camry hybrid. Don't take this "guess" as an absolute scientific result. Note: I used words like could, most likely, probably, etc...

    Dennis
  • venus537venus537 Member Posts: 1,443
    speaking of high mileage cars, what about the new passat diesel? in "real" world driving the passat gets very close to the prius in gas mileage?

    and with the passat's much better interior, ride, handling and performance, tell me again why one should get the prius.

    emissions and reliability perhaps.
  • venus537venus537 Member Posts: 1,443
    well i be disappointed in honda if they don't make any significant improvements and innovations to their IMA hybrid system with the accord. really disappointed if that's the case for the next generation HCH.
  • backybacky Twin CitiesMember Posts: 18,946
    emissions and reliability perhaps.

    You hit it on the button. I was actually considering buying a Passat wagon (1.8T, diesel not yet available here) until I read the horror stories on reliability on the Passat board here. I do wish that Honda and Toyota would bring back the wagon versions of the Accord and Camry, though. As hybrids, of course. I prefer the wagon configuration to SUVs.
  • mistermemisterme Member Posts: 407
    I thought this thread was entitled:
    Honda Accord Hybrid vs. Toyota Camry Hybrid

    Not just another Prius VS HCH vs ICE board again!
    IMA VS Sentry we can deal with!

    Back to post #18 by lexusguy:
    Still Accord will sell more if there isn't any Camrys on the lot!
    Steve
  • alpha01alpha01 Member Posts: 4,747
    This is a quote from a TMMK employee from another message board

    "V6 Powertrain had an announcement today concerning a "new" V6 engine they would be building for the 2006 Camry and Avalon."

    I dont know if that directly answers your question, but that statement was also accompanied by one that indicated the phase out of the 3.0L V6.

    ~alpha
  • andy71andy71 Member Posts: 96
    Toyota just introduced the "new" 3.3L V6 for Toyota Camry SE and Highlander, Lexus ES and RX; will this engine be obsolete within 2 years of its introduction?
  • i_luv_toyotai_luv_toyota Member Posts: 350
    I hate to break it to you, but magazine comparison tests and Car of the Year awards usually have little or no bearing on the buying public.

    The only thing magazine awards are good for are for advertisement fodder. Ad execs eat that stuff up.

    I could personally care less if the Accord (or Camry or whatever) wins anything at all. It's just the magazine's opinion, nothing more, nothing less.
  • alpha01alpha01 Member Posts: 4,747
    The 3.3L engine isnt actually all new, its new in the kind of way that the Ford Freestar is new. It (the 3.3L, 3MZ-FE engine) is a bored-out 3.0L (1MZ-FE). Its certainly a very good engine- with impressive low end torque (242 lb. foot @ 3600 RPM in the RX, HL, and Sienna) but "new", not really in my book.

    As I said, not much is known about the 3.5L- its intended use, origin (ie.. all new or revision of existing), or what will happen to the 3.3L.

    ~alpha
  • bamacarbamacar Member Posts: 749
    Although, I too purchase cars based on my needs and wants, I do find what the car magazines say as group very helpful and meaningful. When all the magazines say the Accord is good at the greatest number of compared categories, I listened. When buying in this class, I also found this to be true. Even Toyota/Camry diehard Alpha just basically agreed above with this analysis. Also, when they all say the Taurus is a dinosaur in most of the relevant categories, I have seen and believe this also. One writer means very little; a unanimous decision by all the magazines says a lot.
  • backybacky Twin CitiesMember Posts: 18,946
    Accord and Camry were the only "inexpensive" mid-sized cars tested by the IIHS in their new side-impact tests to receive a "Good" rating, when both were equipped with side airbags. They got a "poor" rating w/o side airbags, however. The crash simulates a side collision with a truck or SUV at 31 mph.

    http://www.iihs.org/news_releases/2004/pr041804.htm
  • midnightcowboymidnightcowboy Member Posts: 1,978
    VCM - Variable Cylinder Management is estimated to improve higheway mileage 8-10%. will probably be implemented on all Accords as a standard not just the Hybrid Accord. VCM actually shuts down 3 of the cylinders at highway speed to conserve fuel.

    Like the HCH they HAH may weel be offered with a manual 5-speed or 6-speed in a sedan. The current Honda CVT will need to be fortified or redesigned to handle the increased V-6 power. A traditional 5-speed auto will probably be the main offering. However, I will say again, don't discount a manual transmission, even though autos have come a long way a very tall geared maunal would boost the highway mileage another 3-5 mpg and after all part of the challenge is higher mileage wiith out sacrificing perfromance.

    Toyota forgot about the second part of the equation. The Accord will absolutely kill the Prius. Toyotas own Hybrid Highlander will also hurt the Prius sales, especially if the follow Toyota's new pricing model of keeping the price the same as the ICE Hilander, like the RX400H is rumoured
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    I was just using HCH and Prius as an example of IMA vs. HSD of the upcoming HAH and TCH. Since we don't have enough information officially released, we need to do some analysis based on current offerings. That's all :)

    As for supply vs. demand, Toyota is a much bigger company than Honda. Toyota can produce hybrids in the same assembly line as other traditional cars. I don't know about Honda in that case. If there will be any shortage, it will be from Honda. i.e: Assuming there are no shortage of electronic parts such as battery, motor, 32bit CPUs, etc...

    Dennis
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    HAH will need VCM to be able to compete with TCH in performance and fuel economy. I used the word "need" because of the design flaw by nature with the Otto cycle engine. If you understand Partial power and Pumping loss problems, you'll understand how VCM gives a few more MPG.

    You know that when VCM shuts down 3 cylinders on highway, the remaining 3 cylinders will need to burn more fuel to keep up with the same hp output, right? The overall fuel saving comes from reducing Partial Power and Pumping Loss of 3 cylinders but you still have PP and PL problem in the running 3 cylinders plus noise and vibration.

    As you already probably know, HSD Atkinson cycle virtually eliminated PP and PL problems since 1997. Therefore, there is no need to shutdown any cylinder on the highway. In the city, when it needs to, HSD will shut down all the cylinders and run on pure electric.

    You better hope that Honda offers HAH with a manual tranny because it will be the only selling point(10% of the market) over TCH; assuming there is more supply than demand for TCH.

    Toyota had always been one step ahead of Honda. For a compact hybrid sedan, the classic Prius came before HCH. For Mid-size family hybrid car, 04 Prius came before HAH, which TCH will follow to provide more power and performance for more $$. For SUV hybrid, Toyota will have 400h and HH and where is Honda with SUV hybrid? They'll need to make belt, cone, pulley mechanical CVT stronger to make heavier hybrids. How about full size truck? Toyota will have FXT truck. HSD is highly scalable and adaptable.

    With IMA design giving only 36% more power efficiency while HSD gives 91%, the difference will become obvious as the size of the hybrids grow. HSD is also more fuel efficient than IMA. I will calculate how much more some day. It will be embarassing for Honda if HAH gets less combined MPG than Ford Escape Hybrid(HSD).

    BTW, stop spreading incorrect information regarding hybrids comprimise power. Read msg#21 if you are still confuse.

    Dennis
  • robertsmxrobertsmx Member Posts: 5,525
    HAH will need VCM to be able to compete with TCH in performance and fuel economy.

    This is a bad assumption. IMA in its most basic form is just as good as THS without the penalties. VCM is just another improvement to it. BTW, Honda also has a “hot” electric motor setup that they could use if the company wanted to make electric motor the prime mover (like it does in Honda FCX, the fuel cell vehicle). But, with that comes weight penalty. Here is an interesting link I found. Looks like Civic Hybrid and the new Prius are quite close in real life fuel consumption. On average, Civic Hybrid appears to be closer to its EPA rating than Prius though.

    You know that when VCM shuts down 3 cylinders on highway, the remaining 3 cylinders will need to burn more fuel to keep up with the same hp output, right?

    NO. Otherwise, what would be the point? Variable Cylinder Management (or DOD) prevents extraneous wastage of energy. In the top gear, cars usually don’t need the power they get from the engine during cruising. And power costs fuel. With a wider spread of gear ratio, CVTs are known to provide a taller gearing than a regular auto or manual could. VCM closes or stomps that gap.

    Toyota had always been one step ahead of Honda. For a compact hybrid sedan, the classic Prius came before HCH….

    Forget about these statements. Toyota may have come out with hybrid before Honda did, but Honda had electric vehicle in place. But then, GM beat Honda in that regard. Honda has always been considered greener company than any other.

    HSD is highly scalable and adaptable.

    And IMA isn’t? As a matter of fact, it would take little for Honda to hybridize every engine that it sells here in the USA AND offer it with CVT, conventional auto or manual transmission.

    It will be embarassing for Honda if HAH gets less combined MPG than Ford Escape Hybrid(HSD).

    Really? While I don’t want high mileage to be the only strength in the HAH, I suspect with all the “pluses” you have mentioned of THS, it should be Toyota that needs to avoid embarrassment from a much simpler and lighter set up that Honda uses (in real life, not EPA estimates).
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  • usbseawolf2000usbseawolf2000 Member Posts: 759
    Thanks for the link. It confirms that 04 Prius gets on average of 47.8 MPG while HCH gets 45 MPG. 04 Prius is bigger and heavier thus in different class(mid-size) yet more efficient. I have some reasons to believe that as the weather gets warmer, Prius mpg average will go up more than HCH. Even if Honda make their electric assist stronger, IMA can not recharge battery when the car is at rest. I am sorry but I am unable to see from your view of IMA "as good as" HSD.

    I appretiate your point of view on IMA. You are right, IMA does not have to limit to CVT only. Regarding Otto engine making more HP than it needs on highway, we need to discuss much further. From my understanding, Otto engine will narrow down the throttle and allow less air into the engine. Intake valve will also inject a small amount of fuel and keep fuel:air to be able to occur combustion. Is there a limit on the minimum throttling with Honda's V6 engine?

    For example, let's say Accord only need 25hp to maintain 75MPH speed. If Honda V6 can only throttle minimum of, let's say, 40hp, we can expect 15hp extra. Where would the extra hp go? It would go to the wheel right? The car will go faster and the driver will let go the gas pedal. The car will slow down as there are no gas burning at this time. I don't buy that "wasting fuel because the engine is making more power than necessary".

    The two wasting factors in design I see on highway:
    1) The side effect of throttling. When you restrict the air to the engine to create less horsepower, it takes away energy from pistons to create vacuum space inside the cylinders. This is called Pumping Loss problem.

    2) Otto engine is most efficient at the RPM of torque peak, it is very inefficient during supplying only 40hp. This is called Partial Power problem.

    I once questioned about traditional cars, why going faster on highway(high wind resistance) would give higher MPG than going slower(less wind resistance)? I've been told that it is due to stop and go traffic. What if you travel at constant 20MPH, will I get more MPG than going at 70MPH? For Otto cycle engine cars, the answer is NO. For Atkinson cycle engine car, the answer is YES. Any car that I've seen whose city MPG is less than highway MPG suffers from PP and PL problems.

    HSD virtually eliminated those problems with the use of Atkinson cycle. VCM solves only half of those problems under certain situations. The results of current IMA and HSD offering speaks for themselves. The gap will get wider as hybrids get larger. More information about HAH and TCH will be very intersting.

    Dennis

    P.S: Any technical or non-technical views are welcome. :)
  • andy71andy71 Member Posts: 96
    So I am assuming if you were in the market for a 2006 Camry or Accord you would go with the Camry, right?
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    Well, we still don't know pricing, standard features, optional features, performance data, etc... From what I know about these two cars now, I would go for Camry hybrid. :) What about you?

    Dennis
  • robertsmxrobertsmx Member Posts: 5,525
    Prius is considered bigger than Civic primarily because of it being a hatchback. But, Prius weight more (despite of using a very basic platform) is due to the heft that the THS brings. This is a prime illustration of compromises. The funny thing is, despite all the improvements in the new design, the Prius barely beats Civic Hybrid in real situations (Insight stomps them both, badly).

    “I am sorry but I am unable to see from your view of IMA "as good as" HSD.”

    No problem. It is a matter of perspective, and compromises. I would take a more flexible, light and compact package that delivers what it promises.

    “For example, let's say Accord only need 25hp to maintain 75MPH speed. If Honda V6 can only throttle minimum of, let's say, 40hp, we can expect 15hp extra. Where would the extra hp go? It would go to the wheel right? The car will go faster and the driver will let go the gas pedal. The car will slow down as there are no gas burning at this time. I don't buy that "wasting fuel because the engine is making more power than necessary".”

    If you’re cruising at 75 mph, you’re not going any faster than 75 mph, 300 HP or 30 HP won’t matter. All you’re doing with more horsepower (for same speed) is that you’re burning more fuel. The premise of VCM is based on the fact that the engine does not need to burn excess fuel, so in case of Accord, three cylinders will shut down during cruising.

    Assume that Accord V6 delivers 50 HP at 75 mph in top gear (part throttle). With three cylinders turning off, the power equivalent should be around 25 HP. You could achieve the same without VCM if gearing limitations did not come into play, but since they do, VCM is only going to help.

    What is this gearing limitation I just quoted? Pick up gear ratios of any transmission, and divide the first ratio by the last ratio (in a five speed transmission, divide the first gear ratio by the fifth gear ratio). You will notice that the spread will typically be in the range of 5:1 (or that the first gear is approximately 5 times shorter than the tallest gear). CVT has a tendency to provide a wider spread.

    As for pumping loss and partial power problems you quote, I can assure you, the automotive engineers know what they are doing.

    “I once questioned about traditional cars, why going faster on highway(high wind resistance) would give higher MPG than going slower(less wind resistance)?”

    Load and BSFC range play a role.

    “HSD virtually eliminated those problems with the use of Atkinson cycle.”

    I wouldn’t argue on things I don’t understand completely, but based on your argument I notice that HSD is based on a premise of specifics, whereas IMA systems are based on flexibility, and can be adapted to gasoline or diesel engines without much fuss. I prefer the latter.

    Oh, and between Camry Hybrid and Accord Hybrid, my pick would be the Honda. Thanks to my bias for the Honda feel.
  • andy71andy71 Member Posts: 96
    I just bought a 2004 Camry SE V6 and probably will wait at least another five to seven years before purchasing my next car. I have always driven Toyotas and found them to be extremely reliable. I have a 92 Camry LE I4 that still drives like a new car. I have never driven Hondas so I don't want to pass judgments but the hybrid Camry will be on my short list of cars.
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    "Prius is considered bigger than Civic primarily because of it being a hatchback."

        Then how come Prius has more Front Shoulder Room than HCH and more Rear Leg Room than a mid-size Camry? Prius is clearly bigger than HCH for passenger space as well as cargo space. Maybe someone familiar more with different types of car can help out here.

    "The funny thing is, despite all the improvements in the new design, the Prius barely beats Civic Hybrid in real situations"

        Is it also funny that HCH reviewers only get 35-40 MPG? There are Prius drivers in Japan and US that got about 90 MPG. Others get 70+ MPG. Those do not represent majority but average MPG is coming up as the weather gets warmer.

    "If you’re cruising at 75 mph, you’re not going any faster than 75 mph, 300 HP or 30 HP won’t matter."

        It does matters, according to the law of thermodynamic. Where would the extra 270 HP energy go? Loose as heat in the brakes, clutch or torque converter?

    "Assume that Accord V6 delivers 50 HP at 75 mph in top gear (part throttle)."

        Why not throttle further? Put less air and fuel to get 25 HP rather than shutting down 3 cylinders. The answer: throttling creates Pumping Loss and Partial Power problems. VCM tries to cut them down by only half. That's why I said VCM only solve half of the problems.

    "CVT has a tendency to provide a wider spread."

        Then explain why HCH mechanical CVT gets 47 mpg and HCH Manual gets 51 mpg on highway? Something does not make sense. Maybe mechanical CVT has more limitation than you thought? Note: ECVT in Prius has nothing in common with CVT in HCH.

    "As for pumping loss and partial power problems you quote, I can assure you, the automotive engineers know what they are doing."

        You and I already accepted and lived with the design flaw of Otto cycle engines. Slow driving gives less MPG than highway driving. Don't forgot that it should be reverse. Honda engineers are trying to avoid half of the PL and PP problem with VCM technology(bandaid). Prius virtually avoided by using Atkinson cycle.

    "What is this gearing limitation I just quoted?"

        You just described a situation where engine must have the latest technology to fix shortcomings of a transmission. Why not use a better transmission?

    "...based on your argument I notice that HSD is based on a premise of specifics, whereas IMA systems are based on flexibility, and can be adapted to gasoline or diesel engines without much fuss."

        Diesel engine and Atkinson cycle gas engine do not suffer from PP nor PL problem unlike Otto cycle gas engine. Therefore, there is no need for a fix(VCM). Why fix if not broken? HSD does not have to use Atkinson cycle gas engine. HSD can use diesel engine or fuel cell stack. It can even use Otto cycle or Rotary gas engine but why deal with all those inefficiencies?

    Dennis
    P.S: I find replying with quotes gives me direct feedback abilities. If it annoys anyone, I can avoid using quotes.
  • robertsmxrobertsmx Member Posts: 5,525
    Civic and Prius are almost identical in terms of passenger space. Prius has an upper edge in hip/shoulder room (Toyotas, with a typical boxier shape, tend to have more than Hondas that are more rounded). Civic has more headroom, and legroom is virtually identical as well (front and rear combined).

    IMO, Honda should have used Civic 5-door hatch body style for the hybrid. I hope they do it with the next release.

    You mentioned HCH delivering 35-40 mpg, and that certainly appears to be sub par for HCH (and more in line with mileage expected in Civic HX). At the same time, in another link (right here at Townhall) somebody posted picture of his HCH returning 65-69 mpg at the end of a trip. Perhaps for similar reasons that MT is reporting long-term fuel mileage from Prius at 41.9 mpg? That’s way off EPA estimates.

    It does matters, according to the law of thermodynamic. Where would the extra 270 HP energy go?

    Lost to the atmosphere. You could drive all day at 40 mph in first or fifth gear (horsepower will be higher in the first). Do you expect to see same mileage?

    Why not throttle further? Put less air and fuel to get 25 HP rather than shutting down 3 cylinders.
    Already being done, but that most engines would do anyway! VCM only adds to it. That said, does Toyota have a engine/car combination comparable to Honda Inspire (3.0 liter V6/VCM, 247 HP, 3500 lb., 5-speed automatic) in Japan that uses Atkinson’s cycle? If they do, it would be nice to compare how the using VCM compares in terms of mileage (same standards). Of course, we’re going to see VCM in 2005 Odyssey as well.

    Then explain why HCH CVT gets 47 mpg and HCH Manual gets 51 mpg on highway? Something does not make sense.

    The reason is the testing method adopted by EPA to arrive at the “estimates”. In most cars, the methods appear to work reasonably well, but not in all cases. In Japanese market, Honda Odyssey is offered with a choice of conventional 5-speed auto and a CVT transmission. The estimated mileage with the CVT is rated 9% better in the test mode used in Japan.

    That said, my point (to which you responded) was that CVTs tend to offer a wider spread. It’s a fact, and often mentioned as a plus in the technical details.

    You just described a situation where engine must have the latest technology to fix shortcomings of a transmission. Why not use a better transmission?

    And that is?
  • alpha01alpha01 Member Posts: 4,747
    CR uses the same test procedures and fuel economy loops for every vehicle reviewed, so their observed MPG makes it pretty easy to compare vehicles. (This in contrast to car mag test drives where easy comparison is facilitated usually only IN a specific comparison test, and even then, may or may not use the same testing methodology).

    The current HCH achieved 36 MPG in overall driving in CR's hands, and the Prius 44 MPG in overall. The Prius also tested substantially quicker.

    ~alpha
  • robertsmxrobertsmx Member Posts: 5,525
    So does EPA, but that does not mean it is a logical way to compare to reality. Look at the link I provided earlier, and there is a substantial variance. Some folks with Insight have recorded excess of 90 mpg with Insight, and thats outstanding. EPA estimates (or CR's for that matter) don't seem to come close.

    For most "conventional" cars, EPA estimates are decent benchmarks. My experience has been within range of the estimates (I get 1-2 mpg better in my Accord, both city and highway) than EPA ratings. It would be interesting to see how much variance I will see with not so conventional vehicles under the same circumstances. HCH happens to be more conventional than TP though, so I expect to get 45-50 mpg from the car, if not 65-69 mpg that a person has reported elsewhere.

    C&D obtained 42 mpg during its test drive of Toyota Prius (EPA estimate: 59/51 mpg). Civic Hybrid road test in C&D did not have an overall mileage number, but the following:

    “We measured 38 mpg during our time with the Civic hybrid, flogging it mercilessly to pass on mountain roads around L.A. On our most sedate section—at 70 mph on a level, flat interstate—we saw 49 mpg on the trip computer.”
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    "Lost to the atmosphere. You could drive all day at 40 mph in first or fifth gear (horsepower will be higher in the first). Do you expect to see same mileage?"

    Lost to the atmosphere through what? You did not specify. Assuming gears are that close which in a real car, you would damage the engine for driving at first gear instead of fifth. Your question should be, "Is driving at 7,000 RPM the most efficient or driving at 1,000 RPM". The answer for Otto cycle is neither. At low RPM, Otto suffers from PP and PL. At high RPM, it suffers from friction loss and expansion ratio. The most efficient RPM is where Otto cycle create the most torque. Unfortunately, we always don't need the same load from engine. Therefore, we are forced to use other inefficient Otto cycle RPMs. In contrast, Prius Atkinson cycle engine is very efficient from 1,500 to 5,000(max limited) RPM.

    I do not know any Toyota car equivalent to Inspire. That's why HAH vs. TCH will be interesting. BTW, Atkinson cycle engine does not make sense for ICE only car unless it is supercharged. Mazda tried it but the extra cost added by supercharger offset it. But it does make sense in hybrid due to the high torque electric motor(supercharger).

    Regarding MPG from the link you provided, it has sample size of 12. Not enough to draw any conclusion.

    Dennis
  • usbseawolf2000usbseawolf2000 Member Posts: 759
    "You could drive all day at 40 mph in first or fifth gear (horsepower will be higher in the first). Do you expect to see same mileage?"

    Short answer: No. If there is no stop and go traffic, driving at constant 40 MPH in first gear will get less MPG than in 5th gear but not by much. The difference will be directly related to the friction loss due to high RPM of the engine.

    Long answer:
    If the car is traveling at constant 40 MPH at max RPM, it takes little gas to keep up at that RPM. Initially, it would take a lot of gas to bring up engine RPM from 0 to max RPM at full throttle. In this state, the engine would have a lot of horse power in the form of potential energy. You can use it to accelerate by shifting into higher gear right away.

    If you cruse at 40 MPH at 1,000 RPM, it will also take little gas to maintain at that RPM. You will save a lot of gas initially but you are not prepare to pass other cars. The engine will need more gas to build up RPM first before you downshift.

    So, if the engine is at max RPM maintaining 300 HP, it is not at full throttle. The only fuel it takes to keep it at 300 HP is to counter the engine drag. The engine is at full throttle only when you are revving up;going from idle to max RPM. A big difference. I think you were confuse between those two.

    Back to VCM example where V6 is maintaining 50 HP but only need 25 HP to overcome high speed drags. VCM will disable 3 cylinders to maintain only 25HP. Overcoming this 25 hp drag(due to high speed) takes about the same fuel either V6 or I3. 3 cylinders will have more fuel in it compare to the same amount of fuel spread out in the 6 cylinders. The increase in efficiency comes from less cylinder drag and less throttling of the 3 cylinders; i.e: less pumping loss and partial power.

    Dennis
  • andy71andy71 Member Posts: 96
    Why do you think the Prius is selling so much better than the Civic Hybrid even though I think the Prius actually costs a little bit more? I know you like Toyota's HSD better than Honda's IMA ( I hope I got it right)?
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