Almost a month into my TCH owning experience, which followed over two years of driving a Gen-II Prius, I’m left wondering if the TCH didn’t actually get the wrong engine. As most know, the TCH ICE is essentially the same engine as the regular I-4 Camry, the 2AZ 2.4L, though of course, it’s tuned much differently in the TCH than in the gasser (primarily to add Atkinson cycle operation) for greater fuel economy. This results in a car that’s substantially faster than the I-4, and in fact, is pretty much on par with the previous generation V-6 cars (but certainly not as fast as the current 3.5L V-6s, that have about 100 more hp).

I realize that there’s a balance to be struck in every design, and the TCH and its cousins are no different. This said, it looks like Toyota took a step or two in the direction that led Honda to disaster with its Accord hybrid, where they emphasized power so much that the fuel savings were negligible, and customers passed on it in droves. At least we have an I-4, not a V-6.

So here’s what I’m wondering – why didn’t Toyota use the 1.8L I-4 (they could have pulled the Corolla/Matrix engine pretty much off the shelf) as the ICE in this car? With the electric boost, in theory anyway, they could have achieved performance on par with the regular I-4 (no race car, but not bad; I’ve had a couple as rentals), and delivered even better fuel economy than we already get.

The Prius does pretty well with an almost tiny 1.5L ICE, though it’s electric side is more powerful, in relative terms, than that in the TCH. I was fine with the Prius’ performance, and I think I’d be willing to trade some ultimate “go” in the TCH for even better mpgs. Am I out to lunch, or does this make sense?

 

I had a 2003 Corolla that got 40 mpg combined. That was very slow takeoffs and driving 55 on the highway. The new Corolla weighs 2530 lbs.

The TCH weighs 3680 lb. Toyota engines are setup with very tight clearances. I did not have extra power till after the first oil change at 5000 miles. I saw my gas mileage increase at just over 8000 miles. I did switch to the 0W-20 full synthetic on my first oil change. That may be the reason it took mine longer to get fully broke in.

It's best to use one of these gasoline's from toptiergas.com/ Read each link for details. The Prius engine uses a 13.5:1 compression and the Camry Hybrid uses a 12.5:1 compression ratio. Another reason your better off using these quality gasoline's.

I keep 40 psi in my michelin tires after they have cooled.

The TCH should get good gas mileage once it's broke in. The cooler air in late October will pull the hybrids down a few mpg.

The hybrids use the atkins cycle engine due to its higher torque at low rpm. The variable cam helps it achieve a higher rpm if needed.

 

I'd think it's a marketing decision, and a shrewd one.

At least it worked with my wife and I (we own two TCHs).

As 50-ish folks, we want a certain degree of comfort and (I at least) want a certain degree of performance. The TCH's performance is adequate in that regard. Much less, and I probably would have passed.

Every "gasser" I've bought since 1983 has been a V6. And some of those have seemed underpowered.

Again from the marketing perspective, I explain it to folks as a no-brainer... this is a no-compromise car. It's a normal car, but it's a hybrid and gets better gas mileage.

(I leave out how much fun I have driving it.)

I think for hybrids to really catch on, the technology needs to go beyond the early adopters, environmentalists, and frugal folks. (No criticism intended -- I consider myself all three.)

Toyota has come out with a vehicle with demonstrable gas savings that appeals to a more mainstream set of folks.

Gotta run, have a 90-mile drive to do in mine... using 1/2 the gas of the car it replaced.

 

Well, I think my intent was misunderstood. I'm not complaining about the TCH; I actually love the car. This was intended more as a discussion point about whether, maybe, Toyota stuffed a bit too much engine in the TCH, given its target mission (or maybe I just misunderstand the mission).

With that said, a couple things in response. I got my car “used,” it having about 5k miles on it (it’s first owner decided he just had to go back to a full-size truck!). It now has just over 8k miles, and I can see the “final break in” effect happening, as the mpgs ease up. The car is relatively heavy, but with the right combo of motor-generators, I suspect that the ZZ series of I-4 (again, 1.8L in current form) would have provided plenty of go, with even better mpgs.

I’ve used only top-tier fuels for years now, with occasional deviations (such as when supply is disrupted as it was last week). Contrary to what the nay-sayers claim, it does make a difference. Just spoke with a professional acquaintence who drives his TCH 800-1000 miles per week, and he saw mpgs go up when he switched to Top Tier having first used cheap swill for a couple years.

Sadly, my car came with the Bridgestone tires, not the Michelins, which I would have preferred, had I had a choice. I’ve settled in at 42 psi cold, which given the car’s soft suspension, works very well from both an economy and ride perspective.

Respectfully, I’ll partially disagree with the comment re Atkinson cycle (AC) operation. Yes, the HSD cars (except for the Lexus GS and LS models, which are performance hybrids, and aren’t “rigged” for Atkinson cycle operation) use variable valve timing to achieve AC operation. But it’s not for higher torque at lower rpms. In these engines, the intake valve remains open much longer than in a conventional engine, actually allowing the piston to push a portion of the intake charge back into the intake on the compression stroke. When the valve at last closes, the engine compresses a smaller charge. By contrast then, the engine enjoys a full power stroke. In concept, this is actually a form of variable displacement, in which for intake/compression purposes, the engine effectively reduces its displacement, while for power stroke purposes, it retains its full 2.4L displacement. This actually reduces available tq and hp, but greatly increases the efficiency of the engine. The torque loss is substantial enough that in the Prius’ small 1NZ engine, the designers offset the crankshaft to the side to maximize the “leverage” against the crankshaft on the power stroke.

But back to my question: does the TCH have “too much” engine?

 

I don't think I have ever actually needed to use full throttle in my TCH. I have applied full throttle just a few times, but in each case a little less power would have been acceptable. Hence, a smaller displacement engine (like the 1.8L instead of the 2.4L) would work just fine.

However, I doubt that using a 3/4-sized engine would give dramatically better mileage. For normal cars and trucks, a bigger engine translates into lower FE mainly because it is using more fuel at idle, and at speeds where the engine produces more torque than is really needed. In this hybrid design, both of those problems are solved by the hybrid system, so the output of the gas engine is used efficiently. The weight savings might be worth something, and it might get slightly better mileage, but I doubt it would get anything near 33% better mileage. It really does take a certain amount of energy to move (roughly) 3400 pounds a given distance, assuming the same friction losses and all that.

Auto makers have been providing a choice of engines in many models for many years. As they phase out non-hybrid gas engines, I would not be surprised to see them provide a choice of two different hybrid engines in the Camry line. The current TCH is a lot like the XLE trim. A version with a smaller engine and fewer frills might replace the LE in a few years.

I expect better batteries and software to appear, before then.

 

I think the TCH got the right engine as far as horsepower, etc. is concerned. When hybrid shopping, I was concerned about the amount of horsepower in the Ford Escape Hybrid. My concern was confirmed about a month ago while I was displaying my TCH at a renewable energy fair. One person I spoke with asked about acceleration. She used a Ford Escape Hybrid as a company car from time to time and felt it was very sluggish when trying to pass. So, that said, if Toyota could maintain the current level of acceleration, etc. with a smaller engine, it could be a good option. Either way, I think it is a nice balance and I am very happy with mine after nearly 1 year of ownership.

 

The TCH is not supposed to be a high-efficiency car, it is supposed to be a car for people who want to see better fuel economy without sacrificing too much in the way of size and power.

If someone is comfortable with a smaller engine then they can always get a Prius. I am glad that Toyota put a reasonable engine in the TCH.

 

They didn't put too much engine in it. They put in an engine that would make the overall car appeal to a certain section of the market. Those who are focused primarily on FE (and are satisfied with the performance of a smaller engine) can opt for the Prius, while those who want a larger car that "looks normal" and has more "normal" performance can choose the TCH. Depending on your driving style and how much you try to maximize the FE, it can still show a significant improvement over a gasser.

 

Well, I realize very well that they can't economically give us multiple engine choices in the TCH, at least not at this time, still I wonder... Consider that the present conventional I-4 gives more than adequate power for most drivers. The hybrid gives substantially better. Road and Track says the HyCam is good for 0-60 in only 7.3 seconds (the current V-6 in 6.1). Only a few years ago, that would have been seen as performance car numbers.

The Prius, in my opinion (remember, I drove one for the last 2+ years and still have it actually), too far down the performance scale, doing 0-60 in just under 10 seconds, per the fastest eval I've seen (again, R&T), with some showing over 10 sec.

Would you all have passed on the TCH if it had a smaller engine and performance (other than fuel econ) on par with the regular I-4?

 

Give me an LS with the GSes hybrid drive system, DFI V6, etc, and I'm in the market.
Or an RXh with the Camry's I4 hybrid system but with a Miller/Atkinson/West cycle engine.

Small I4 with SuperCharging via engine drive via a Prius type CVT. Boost varies as a function of throttle position and independent of engine RPM.