I was just looking through some of the official Toyota videos on youtube when I happened to stumble across this explanation of some of the tech in the new Prius. I already knew that Toyota had made some changes to the engine to favor a more powerful, quicker Prius. Despite that, the car received a bump in its EPA ratings.
That’s not too strange, however. It’s common for car makers to split the difference in efficiency gains between power and fuel economy to try to please both of those desires. Usually, however, those same car makers will claim, instead of being honest about splitting the difference, that more power is somehow better for fuel economy.
Toyota is doing the same thing here with the Prius. By claiming that the engine has to work less since it’s bigger, the company is basically lying. If larger engines actually got better fuel economy, you wouldn’t see a sliding scale from small engines with good fuel economy to large engines with poor fuel economy when looking at all cars currently available.
It’s most likely that the improvements in efficiency are due to Toyota’s efforts to reduce aerodynamic and parasitic drag on the engine. So don’t be deceived into thinking that faster and bigger is all of a sudden more fuel efficient.
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if your fuel input is limited you can increase power by increasing the efficiency of the engine. some measures used to increase power along these lines also increase efficiency…
Thanks for the comment Mike. I will agree with you on that point, however, I tend to think we’re being greenwashed a little bit by Toyota here, especially in the way is was stated. While I agree that there are many specific applications of this Toyota’s lack of context made it unfortunately ambiguous what they actually meant.
While bigger isn’t automatically more efficient, I do strongly feel that an adequate engine working within its efficient range is going to return better fuel efficiency than an inadequate engine working its tail off.
I, and many others have replaced aging 2.8L engines in Isuzu 4×4’s with 3.4L engines (same block, same manifolds, etc… so the swap is dead easy) and report nearly universal improvements in fuel economy, above the original EPA estimates for the vehicle.
Toyota seems weak when it comes to ability to explain its own car. I hate to say it but it seems like they are dumbing down for the American market. We are not accustomed to much technical detail from our own companies. After all, about all we have is a fashion industry dressing up the same old car underneath.
One of the biggest advantages of the hybrid can be that it enables the engine to operate over a much narrower range of speeds and power output levels . This enables a tuning process that can be very effective. The larger Toyota engine may be allowing a slightly better tuning to happen. They also may use the battery to even further narrow the range of speeds and power output levels needed. The weight of the engine might or might not go up.
As for regular car engines, putting a bigger engine in a car might not increase fuel usage beyond the weight effect if it is not pressed to a higher level output. Of course, it is very hard to not accelerate faster when it can be easily done. This gets to the question of how much we can depend on human drivers to make objective tests.
What Toyota says makes sense gang. It’s the same thing G.M. discovered with their 33MPG Cobalt. When they came up with the high MPG Cobalt XFE one of the things they had to do was to bump the engine size to a 2.2 Liter from a 2.0 Liter. Then add a new gear ratio, 5-speed stick shift, and low resistance tires and finally Chevy has built a car that I swear to you is currently getting me 45MPG. (EPA says 37, up to 44 possible). Sometimes too small an engine burns more fuel than one a little bit bigger, depending on the weight of the car.
I have been saying for YEARS, the same exact thing as what others and experts are now also saying. Namely, that too small of an engine in a vehicle will get worse fuel economy than a slightly larger and more powerful motor will allow in the same vehicle. Having a true situation in which the motor has to work less hard to propel the vehicle allows for improved fuel economy, let alone the increased fun factor in driving the same car. This is all a “no-brainer” to me. More power, better fuel economy and lots more fun to drive. Why wouldn’t all car manufacturers do what Toyota and GM are doing in this area? It all makes total sense to me.