how efficient is the camry... really?

[illuzionx]

ok, well i havnt posted on the forums for a long time, but like with all my other posts i usually have a story that goes with it.

a family friend has started a business selling a whole lot of stuff (ranging from kitchen appliances all the way to makeup) and ive decided to branch of their business.

my aunt also was selling one of them "raises fuel efficiency" magical additives and she gave me a bottle to sample because i was always skeptical about them and i didnt know if i wanted to sell them as well.

So like any smart person would do, i decided to research the actual fuel additive when another question struck my mind.

How efficient is my gen 3 camry? Not as to compare it to distance and fuel, but as to what percentage of the fuel is actually burned cleanly.

My camry is the 2.2L from the executive so im guessing the 5sfe.

[Loganwiththe'93]

That's actually a good question. I'm not sure if the EPA or DOT will have a posting. I'll take a look for you, but you should look too, as I miss things if distracted. And currently, I have ice cream near by, so I am distracted. :O

[touringcamry]

Internal combustion engines are about 15-20 efficient on average. The rest is lost as heat and friction.

[illuzionx]

not energy produced from each combustion cycle, but how much of the actual fuel is used and how much is wasted during the cycles.

[gregorv]

Here is a great site that I use if I need to find info on fuel economy for a vehicle. http://www.fueleconomy.gov/feg/calculatorSelectYear.jsp It breaks down the economy plus the average amount of barrels of gas burned per year and other inetersting facts. Just tought I would give you the link even though it may not answer your questions.

[touringcamry]

Originally Posted by illuzionx

not energy produced from each combustion cycle, but how much of the actual fuel is used and how much is wasted during the cycles.

I'm not really sure what you are asking... Normally the fuel injectors inject the amount of fuel needed for stoichometric burn after measuring the amount of air and air temperature. So you have about just enough fuel to for the amount of air in the combustion chamber.

There is a point where the fuel injectors will inject a lot more fuel for things like heat soak if the engine is running at high RPMs. I think this changeover happens around 4000 to 5000 RPMs. When this happens, a lot of the fuel will go unburned and I don't know the ratio when this does happen.

[Tom 2000]

Gasoline engines in general are pretty inefficient at about 25-30%. Read the wikipedia article below. It goes into some detail.

http://en.wikipedia.org/wiki/Engine_efficiency

If you were to take two engines, let's say 2.2L. One engine has an inline 4-cylinder configuration and the other engine has an inline-6 cylinder configuration, the 6-cylinder engine will be less efficient as it will have more frictional losses from more parts sliding past each other (more pistons, more vales, more connecting rods, more main bearings, you get the idea.)

Older engines used 2-valves per cylinder, whereas most modern engines use 4 valves per cylinder. With more valves, you can increase the volumetric efficiency of an engine, but there is some price to be paid with additional friction as you need to actuate more valves, lifters and compress more springs.

5S-FE engine with 4-valves per cylinder, pentroof combustion chamber is a much more efficient design compared to a 2-valve per cylinder overhead valve engine from 30 years ago. It can run at higher compression ratios given the same fuel without knocking/pinging.

Newer engines utilize technologies such as Variable Valve Timing, Direct Injection, etc.. to make the engines more efficient across a wider powerband to turn energy from gasoline to horsepower, but it's still relatively small increments at best.

Let's put it this way. Any properly working diesel engine will always be more efficient than a gasoline engine,

Take a look at this article also.

http://en.wikipedia.org/wiki/Thermal_efficiency

[uuuuu]

If I'm not mistaken, the OP wants to know how much unburnt fuel comes out of the engine, not how efficient the entire cycle is with heat losses and such. In that case, I think touringcamry has it right.

[Luckynumber5]

Well it's tricky to say. You can hook a wideband up to any car and get a pretty accurate idea as to how well the factory ecu manages the engine.

My 92 v6 for example, has two very old style 02 sensors (unheated) and manages to fluctuate within .4 air/fuel of 14.7 at cruise, but has lots of problems elsewhere.

The older engines have poor tuning for acceleration. On takeoff from a stop the air fuel fluctuates from ridiculously rich to slightly rich where it needs to be. This is probably because of the factory tables and slow processing capability of the factory ecu. Newer engines with nicer 02 sensors and more processing power can trim off excess fuel on takeoff resulting in a leaner more efficient burn.

The compression ratio, whether or not the engine has an egr, port styling and cam lift/duration all play into how well an engine burns. Efficiency may be sacrificed for reliability and most of the time ease of production, a good example is the poor port setup on many factory Toyota heads. You may think porting and valve jobs are only for performance but truly both are making the engine more efficient (if the machinist knows what he is doing)

The compression ratios are kept low to help deal with most people running low octane gasoline, this afects piston top design, quench area design (which also plays into production cost cutting)

An engine with low compression will burn slightly less efficiently than the same engine with a higher static ratio, but problems can arise if the fuel decides to detonate under pressure before the engine is ready (pinging)

The newest Toyota direct injection engines don't need to worry about running higher compression ratios with low octane fuel because the fuel doesn't hit the hot combustion chamber until just before the ignition event, which avoids heat soaking the fuel and allowing for much greater efficiency and performance. At a high cost of manufacture though.

[illuzionx]

so from what i can gather older engines dont burn the fuel as efficiently? if so, where does that put my gen 3?

in the older category, or the modern category?
it was one of the older gen 3's 92/3?

[camry6]

Originally Posted by illuzionx

so from what i can gather older engines dont burn the fuel as efficiently? if so, where does that put my gen 3?

in the older category, or the modern category?
it was one of the older gen 3's 92/3?

I have a '93 v-6 3vz-fe, and I would think that comparing to todays technology- were both sittin'in the older category.

[Tom 2000]

Here's something to put into perspective.

These are the official numbers from edmunds.com and fueleconomy.gov for a Camry LE sedan with 4-cyl engine and automatic transmission.

84-86 Camry 23/29 MPG (Old EPA 26/32 MPG) 2.0L 4AT 92-95 HP
87-91 Camry 22/28 MPG (Old EPA 25/31 MPG) 2.0L 4AT 115 HP (2811 lbs)
92-96 Camry 18/25 MPG (Old EPA 21/27 MPG) 2.2L 4AT 135-125 HP (3053 lb)
97-01 Camry 20/28 MPG (Old EPA 23/30 MPG) 2.2L 4AT 133-136 HP (3086 lb)
02-04 Camry 21/29 MPG (Old EPA 23/32 MPG) 2.4L 4AT 157 HP (3086 lb)
05-06 Camry 21/31 MPG (Old EPA 24/34 MPG) 2.4L 5AT 160-157 HP (3108 lb)
07 only Camry 21/30 MPG (Old EPA 24/33 MPG) 2.4L 5AT 158 HP (3307 lb)
08-2009 Camry 21/31 MPG 2.4L 5AT (3307 lb)

Compared to a gen3, a gen6 Camry weighs about 250 lbs more, makes 28 more horsepower and gets better fuel economy.

The engine has gotten much more efficient (and bigger), but the 5-speed automatic and better aerodynamics play a role as well.

[gladis]

I never figured out why the EPA's numbers were so low for my Camry. In combined driving, I've always gotten about 26-27 mpg, and even in my early days of driving in hs, which meant <50 mi/tank highway driving, I never dropped below 21-22, and I was driving like a maniac in those days too.

The lowest I've EVER gotten on a tank was 19 mpg (routinely revved up to redline, and highest ever was 33 mpg.

The EPA numbers seem to be right for my other cars though, the Sienna gets about 20mpg and the Merc about 23 mpg.

Anyone else experience this discrepency with their 5sfe gen 3?

[dans01camry]

Well I have to say that for my Gen4 (23/32) The best I achieved was 35.13 and that was with driving 271 miles (50 in LA, 60 over the grapevine, and the rest up through Fresno, CA). The average mileage I get with hwy and city is about 26-29