Automotive

Toyota bucks the downsizing trend with more efficient 1.5-l engine

Toyota bucks the downsizing tr...
The new 1.5-liter engine, set to do service in the Toyota Yaris
The new 1.5-liter engine, set to do service in the Toyota Yaris
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The new 1.5-liter engine, set to do service in the Toyota Yaris
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The new 1.5-liter engine, set to do service in the Toyota Yaris

As emissions regulations get tighter, congestion gets worse and consumers demand better fuel consumption from their cars, manufacturers are being forced to delve deep into their engineering kitbag for clever ways to save fuel. The latest brand to unveil a smart new eco-friendly engine is Toyota, which has released a parsimonious 1.5-liter for the Yaris.

Although some brands have stuck put their faith in downsized, turbocharged engines for better performance and efficiency, the new engine destined for the Yaris in actually 200cc larger than the one it replaces. It's also still naturally aspirated, ignoring the current focus on strapping a turbocharger onto every available engine block.

Power is up from 63 kW (84 hp) to 82 kW (111 hp) in the new engine, and the peak 136 Nm (100 lb.ft) of torque is a handy 15 Nm (11 lb.ft) more than before. Thanks to these gains, cars fitted with the fresh engine will hit 100 km/h (62 mph) in 11 seconds, an improvement of 0.8 seconds. Performance between 80 and 120 km/h (50 and 75 mph) has also improved, although you're unlikely to win any rolling drag races given the 17.6 seconds it takes.

Although the extra power is nice, the real reason for the new engine is the upcoming Euro 6C emissions regulations, along with a new Real Driving Emissions test. To make sure it shines under the strict new conditions, designed to deliver more accurate real-life results than the current emissions testing procedure, Toyota has turned to lessons learned while developing petrol engines for its hybrid range.

The engine runs with a sky-high 13.5:1 compression ratio, made possible by new pistons and a new combustion chamber designed to deliver the perfect air/fuel mixture every time. A cooled exhaust-gas recirculation system helps lower combustion temperatures, crucial for making sure you don't suffer "knock" while running such a high compression ratio.

Depending on the type of driving, a variable inlet valve timing system (VVT-iE) allows the new engine to switch between the Otto and Atkinson cycles on the fly. Under light loads, the electrically-controlled system runs the engine on the Atkinson cycle, keeping the intake valve to open beyond bottom dead center in the piston stroke. When the driver calls for more performance, it switches back to the Otto cycle.

The result is a claimed 12 percent improvement in fuel efficiency under the current testing cycle. You can expect to see it in the facelifted Yaris, set to launch this March.

Source: Toyota

7 comments
Bob
0-62 mph in 11 seconds? I didn't realize the Prius was so slow. I had considered looking at one but not now. Since I keep cars for a long time, replacing the battery after a few years cancels out any fuel savings on the short term.
Bob
Are small engines really more fuel efficient??? Maybe they are to some extent but I really have to wonder when I have a 430 hp rear wheel drive car that gets 24-27 mpg combined highway and city driving. This is only three mpg less than the 27- 30 mpg my other car gets and it is a four cylinder 178 hp front wheel drive Toyota which weighs the same 3200 lbs. The biggest difference is the 430 hp requires premium gas but can run on regular if necessary. Of course the larger engine could burn much more gas if pushed but for overall driving there isn't much difference. It just seems like something is wrong that the smaller engines can't do much much better.
JohnnyWhite
Consumer Lab gives the Yaris a high rating for reliability, if not for anything else. The new engine seems less likely to provide as high reliability, due to it's complexity.
PaulEckerson
They omit a lot of information. Curious about entire engine weight, demensions, # of cylinders, materials used in engine, and of course long term reliability.
npublici
Let's hope that they will put studs,coarse threaded bolts or steel coarse outter threaded inserts in for the block/head connection. I would hate to see a repeat of their infamous head bolt stripping and their sick response to affected customers.
neutrino23
This is a Yaris, not a Prius. Prius batteries last a long time. They are guaranteed for 8 years. Ours is 12 years old and still working fine. This kind of work seems typical of Toyota. They make a lot of small engines, mostly for Asia, maybe also Europe. They are constantly tinkering with adjustments to improve performance while reducing emissions and cost.
Vf6cruiser
A Yaris in SoCal is a death wish. You will tremble at every on ramp, grit your teeth and hope the next semi doesn't squash you like a bug.