[Daox]

I was reading up on Toyota engines the other day and came across this gem of a page that outlines all the new technology that they put in the the NR engine series. I believe the only example we have here in the US is the 1NR-FE. It is a 1.33L 4 cylinder engine that was used in the Scion iQ as well as many vehicles overseas. More importantly and just interestingly is the technology they put into it.

Toyota NR series engines

Here are some notable 1NR-FE fuel economy features. There is a ton more info in the link provided though.

Offset crankshaft. We've heard about these for quite a while. Seems to be almost a normal engine feature these days.


This one is new to me. In addition to the added cooling at the top of the cylinder bore, it would also reduce the amount of coolant in the system which should decrease warm up times. This of course assumes they made it out of something that has a lower thermal mass than water, which is quite likely.

There is the spacer in the water jacket installed, it allows more intensive coolant circulation near the top of the cylinder, which improves heat dissipation and helps to more evenly thermally load.

This doesn't seem to be for fuel economy, but is interesting IMO. It seems anodizing the piston ring groove is an anti-friction measure, and PVD coating is a very hard coating that would extend the life of the piston ring from wear against the cylinder wall.

Pistons - alloy, compact T-shaped in projection, with cutted skirt. The groove for the upper compression ring is anodized, the edge of the upper compression ring and oil scraper have anti-wear PVD coating.

I see the borrowed some gen 3 Prius tech here.

Versions for cold climate area are equipped with coolant heater (by exhaust gases). In the central pipe the valve actuator with the thermostat is integrated: after cold starting gases pass through the heat exchanger, then as the valve opens and the heating gases already flow to the exhaust.

And the smart alternator.

Charging system - with segment conductor alternators, 80-100A output, one-way clutch in pulley.
Continuously charging of battery is carried out during deceleration, but in steady-state mode cycles of charging and discharging of the battery are alternates for maximum efficiency. More complex control system required to use the battery temperature sensor and current sensor.

Next, it moves on to the 8NR-FTS, a 1.2L direct injected and turbocharged version. This engine is fitted to the Toyota Auris.

Uses VVT-iW which allows for Atkinson, or Miller cycles.


Here is a better showing of the piston technology. Anti-friction coating is added to the piston skirts. I think this is pretty common now as well.

1 - piston, 2 - anti-friction ring carrier, 3 - upper compression ring, 4 - lower compression ring, 5 - oil ring, 6 - expander. a - combustion chamber, b - polymer coating, c - compression height, e - PVD coating, f - chrome coating.

Integrated exhaust manifold into the head. This speeds up warm up times, and seems to be common as well.

- The exhaust manifold is integrated into the cylinder head.

This is something I've never seen before. Its a two thermostat system. The head warms up first. Then, the first thermostat opens to warm the block. Then the 2nd (traditional) thermostat opens to the radiator to cool the system.

The engine is equipped by two thermostats:
- Traditional thermostat (opening temperature 80-84°C) in the water inlet controls the coolant flow through the radiator
- Thermostat on the cylinder block (opening temperature 76-80°C) controls the coolant flow through the block, to maximal fast warming up


1 - cylinder head, 2 - water inlet, 3 - thermostat (block), 4 - cylinder block, 5 - water pump, 6 - throttle body, 7 - thermostat, 8 - intercooler reserve tank, 9 - radiator, 10 - bleeder valve, 11 - heater radiator, 12 - CVT fluid warmer.

More Prius tricks.

ECM controls the coolant flow rate and cooling efficiency by electric pump speed.