[Orion]

How did they get better fuel economy numbers out of a larger motor with more horsepower?

 

[binko]

I suspect that it is a number of small sperate possible reasons:
Car slightly lighter
Improvements in the CVT transmission efficiency and shift logic
Better Aerodynamic design for less wind resistance.
Improvements in engine combution efficiency and higher compression ratio

I think that it's an overall combination of the above and not just a single change.

 

[5TAR]

^ That's exactly it, aiming for cutting weight and improving efficiency with the power unit, that's really what it comes down to and when you consider what can be done with those two areas to target... it breaks down to quite a lot to potentially go after.

 

[Pinetop]

lighter car plus more horsepower means the engine works less hard. Plus CVT in the sweet spot.

 

[jamis]

I think, once we see the EPA testing results, that the Earth Dreams design is much more efficient than the r18a it replaces. The other things mentioned also contribute a great deal in the resulting MPG. Honda is no slouch when it comes to engineering. I have been impressed that the r18a is more efficient than Chevy's 1.4L turbo motor. Better mileage and lower emmisions, so this new 2.0L NA motor is bound to be better.

 

[Civil]

I think that it is fairly obvious at this point that power is not something that can only be had at the expense of efficiency. I think that is exactly what technological advancement has been focused on in recent years.

 

[dB super E-spec]

I think, once we see the EPA testing results, that the Earth Dreams design is much more efficient than the r18a it replaces. The other things mentioned also contribute a great deal in the resulting MPG. Honda is no slouch when it comes to engineering. I have been impressed that the r18a is more efficient than Chevy's 1.4L turbo motor. Better mileage and lower emmisions, so this new 2.0L NA motor is bound to be better.

As mentioned above, fuel economy numbers don't come entirely from the engine. Note that the 2015 Civic HF gained a 2mpg higher rating simply through lightweight aerodynamic wheels, thinner tires, rear spoiler, underbody panels and slightly lighter weight.

Speaking of which, note too the MPG. 2015 HF R18: 31/41/35 combined. 2016 LX K20: 31/41/35 combined.

Personally I'm not convinced that the R18 is the less efficient engine, but it was at the peak of what can be done with SOHC. The K20's advantage is that it's DOHC which allows more precise valve control with dual VTC, as well as a future upgrade in the form of direct injection.

 

[Pinetop]

I think that it is fairly obvious at this point that power is not something that can only be had at the expense of efficiency. I think that is exactly what technological advancement has been focused on in recent years.

Power costs without a doubt. But you can reduce the impact of increased power through increases in efficiency.

See Formula 1.

 

['13_Si]

Efficiency of the entire car. Don't just focus on the engine. I'm not saying it isn't more efficient, but there is more to making a car efficient that focusing on it's engine. It's a total package.

 

[10thGenCivic]

The current K20 makes 158 horsepower and displaces 122 cubic inches. That is 1.295 horsepower per cubic inch.


The previous R18 makes 138 horsepower and displaces 109.8 cubic inches which is 1.256 horsepower per cubic inch.

The new 2.0 K20 is an improvement!