New 1.5 engine for the Yaris - replacing the 1.33

[FROSTYBALLS]

See http://blog.toyota.co.uk/new-1-5-litre-petrol-engine-for-toyota-yaris

[Konrad C]

Same 1496cc capacity as the Mazda 2 SkyActiv engine, but different power/ torque figures. What about the 1.2 engine? 

I assume it may be cost cutting through shared resources. The 1.2T is a more complicated engine. 

[Justhandguns]

Nice, even though I have no plan to switch in any time soon. I think engine emissions will be less relevant in the UK after April as the new road tax scheme sets in.

[FROSTYBALLS]

Presumably the 1.2T was discarded due to cost, which was the same reason for dropping the stop/start function from the 1.33 when the third generation Yaris was introduced (though the Auris continued with the stop/start system). Presumably the 1.5 engine will be fitted to the Yaris in other markets (eg Asia-Pacific) and will provide a greater degree of standardisation.

When the 1.2T was introduced, it was supposedly just for Toyota's European models.

[bathtub tom]

" the introduction of a new water-cooled exhaust manifold. By limiting the gas temperature, this avoids the need for mixture enrichment to reduce combustion temperature at motorway driving speeds. As a result, both fuel consumption and exhaust emissions are reduced."

I fail to see how reducing the exhaust temperature avoids the need for mixture enrichment. I would have thought the reduced temperature would result in a denser gas, thus increasing pumping loss.

[TAuris]

29 minutes ago, bathtub tom said:

" the introduction of a new water-cooled exhaust manifold. By limiting the gas temperature, this avoids the need for mixture enrichment to reduce combustion temperature at motorway driving speeds. As a result, both fuel consumption and exhaust emissions are reduced."

I fail to see how reducing the exhaust temperature avoids the need for mixture enrichment. I would have thought the reduced temperature would result in a denser gas, thus increasing pumping loss.

Another strategy to reduce NOx, since employing an EGR valve in a petrol engine was not a great idea in the first place. The 1NR-FE engine is a testimony to this.