Toyota Auris to Offer New 1.33L Dual VVT-i with Stop&Start
19 November 2008
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| Toyota Optimal Drive 1.33-liter Dual VVT-i gasoline engine with Stop&Start. Click to enlarge. |
Toyota is applying its new 1.33-liter, Dual VVT-i gasoline engine with Stop&Start in the Auris. The engine is also to be applied in the iQ. (Earlier post.) The new 1.33L engine in the Auris delivers a 19% improvement in fuel consumption and a 17% decrease in CO2 emissions compared to the previous 1.4L VVT-i unit.
The new Auris 1.33 Dual VVT-i Stop&Start is being branded as an “Optimal Drive” vehicle. (Earlier post.) Toyota Optimal Drive covers a range of different technologies that can be applied to achieve real-world results in decreasing fuel consumption and emissions without compromising driving pleasure. This approach, Toyota says, is in contrast to “some car manufacturers which have elected to launch special eco-themed models with design, engineering and equipment tweaks to achieve lower emissions and better fuel consumption, often at the cost of comfort and driving pleasure.”
All new Toyota models will benefit from Toyota Optimal Drive, with new iQ, Avensis and Auris 1.33 Stop&Start as the first instances.
The all-new 1.33-liter Dual VVT-i engine represents the latest in Toyota lightweight powertrain technology. Benefiting from Toyota’s motorsport experience, where compact and powerful engine design is crucial, the new unit is 54mm shorter and 127mm narrower than the previous 1.4-liter VVT-i and weighs 13kg less. The result is a four-cylinder engine that is the same size as a three-cylinder 1.0-liter VVT-i. Its small bore and long stroke design gives a narrow block and reduces weight to give a very high power-to-weight ratio.
New pistons were developed with a smaller contact area to help produce quick and efficient combustion. Piston weight was also significantly reduced, from 280g to 180g—a 36% saving—which means they use less energy. For leaner combustion, an oil jet was integrated into the design.
The new engine gives a solid torque curve that suits everyday driving. Output is 100 Nm per liter, with a maximum 132 Nm (97.4 lb-ft) developed at 3,800rpm.
Toyota engineers streamlined the intake channel and used computer simulation to optimize airflow. Surfaces were made smooth and any angles or sharp edges were rounded off to help reduce turbulence.
More weight has been saved by using a cylinder head cover and resin intake manifold. In addition, the highly rigid aluminum crankcase is connected to the transaxle casing, improving rigidity of the joint in the powertrain and thus reducing noise and vibration. An all-new camshaft profile was designed, reducing weight and friction.
Dual VVT-i (variable valve timing—intelligent) provides continuous, variable control of both the intake and exhaust valves to optimize performance and fuel consumption. This also yields more torque at low engine speeds and helps reduce exhaust emissions.
Auris is the first model in Europe to benefit from Toyota Stop&Start technology. When the car is stationary, with the transmission in neutral and the driver’s foot off the clutch pedal, the engine automatically and quietly stops to reduce fuel consumption and emissions. When the driver re-engages the clutch, the engine automatically restarts. This brings particular benefits in urban traffic, with a potential 15% improvement in the amount of fuel used and CO2 emissions.
Toyota’s Stop&Start system has a permanently engaged starter gear mechanism—the starter motor is in direct contact with the ring gear on the engine, which means the engine stops and starts quickly and quietly. Compared to the 1.4 VVT-i, the start-up noise level has been reduced by 9dB and starting time cut from 0.7 to 0.4 seconds.
The engine is matched to newly developed six-speed manual transmission, with ratios calculated to deliver the best possible balance of performance and fuel economy. The twin-shaft unit is 11% smaller and has 15% fewer components than the five-speed unit, but has a higher torque capacity. Friction is reduced and the driver enjoys an improved gear shift feel. Using an extra gear compared to the transmission used in the previous Auris 1.4, VVT-i, it also gives more refinement at high speed.
From October 2009, the 1.33-liter Dual VVT-i engine will be manufactured at Toyota Motor Manufacturing UK’s (TMUK) factory at Deeside in North Wales. Almost €115 million has been invested in the plant in the past year to prepare for production of the new engine, which comes in addition to the €1.12 billion invested in operations since the factory opened in 1992.
Deeside currently produces 1.4, 1.6 and 1.8-liter VVT-i petrol engines at a rate of about 185,000 units a year. It also undertakes casting and machining of engine sets for export to other Toyota plants around the world. Until Deeside production comes on stream Auris will be fitted with engines manufactured in Japan.
| Performance comparison new Auris 1.33 Dual VVT-i vs Auris 1.4 VVT-i | ||||||
|---|---|---|---|---|---|---|
| 1.33 Dual VVT-i | 1.4 VVT-i | |||||
| Max. power (bhp/DIN hp) | 100/101 | 96/97 | ||||
| Max. torque (Nm) | 132 | 130 | ||||
| Fuel consumption combined cycle (L/100km) |
5.8 | 6.9 | ||||
| CO2 (g/km) | 135 | 163 | ||||
Looks great - pity we have to wait till October 2009 to get it. Much less urban pollution than a diesel, much cheaper than a Prius (I am assuming).
Be nice to see that engine in a Yaris as well.
What is great is that these are real cars what will be sold in bulk (assuming the economy survives), not some concept car or an EV that they will build 300 of in 2009.
Posted by: mahonj | 19 November 2008 at 03:32 AM
Is the new Auris bodyshell lighter too?
Posted by: clett | 19 November 2008 at 04:38 AM
Seems to be another step in the right direction. Most ICE driven vehicles could benefit from similar improvments. Thank you Toyota to continue making more frugal cars.
What is the power to weight ratio of this new ICE, with and without essential attached accessories?
What is the energy efficiency, i.e energy in vs energy out (to the drive shaft) of this new ICE?
Posted by: HarveyD | 19 November 2008 at 08:27 AM
Pretty good, why not add a small motor and battery / capacitor assembly to provide regenerative braking and launch assist?
As battery technology improves you can just add battery equivalent for 10, 20 or 30 miles all electric travel.
Replacing the petrol used in commuting with renewable electricity should be a priority.
Build new high speed rail lines along with HVDC transmission networks & fibre optic date cables connecting load centres, line them with wind turbines.
Build some co-firing coal/biomass gasification with natural gas combined cycle power plants with concentrating solar boost for summer peaks.
Vent the emissions into large stacked greenhouses growing biomass to be made into composite materials.
Use the waste heat for fish farming, and composting all suitable material.
Switch resistive electric heating to air source heat pumps.
Use nuclear power to push coal off the grid and charge car batteries overnight.
Standardise rules on car sales across the EU and the US. With lower sales volumes low cost high volume manufacture will only be effective if the same vehicles can be sold in most of the worlds markets.
Posted by: | 19 November 2008 at 09:01 AM
Frequent stop & start cycles increase stress on the starter motor/gear, requiring larger motor/gears for durability. A larger starter motor or a high-quality brushless motor increases weight and cost...Why not follow the Honda's IMA approach and simply have a large-diameter flywheel-starter-generator integrated into the engine...no gears are required and none to wear out...the weight of the flywheeel is eliminated...
What about cost? Hmmm...Honda already has reduced the cost of their upcoming Insight hybrid to be competitive with non-hybrids...
But, Toyota is to be applauded for raising the bar quite a bit higher for all cars, and it will be likely that other auto mfg's will follow suit...Someday, all ICE cars will have some form of electric hybrid.
Posted by: Roger Pham | 19 November 2008 at 10:16 AM
Doesn't say otherwise so it must be 12 Volt system. For an engine this small 12V is sufficient for start/stop.
The Saturn VUE 2.5L with start/stop uses a 36V battery.
Posted by: DS | 19 November 2008 at 12:45 PM
Very nice. A small improvement here, a small improvement there, pretty soon you get a good set of all around improvements. I can see some very smart anti-magic bullet thinking and strategy here.
Posted by: Lulu | 19 November 2008 at 12:59 PM
Good question:
IQ weighs 845kg in petrol form so its power to ratio is 118bhp/tonne.
For comparison sake, an Accord (US Accord, not the TSX)is 3410lb or 1550kg and makes 190hp@7000rpm and 162@4400 (foot-lbs) of torque.
So it has 122bhp per tonne.
I'm not knocking the Accord, maybe someone can do a more appropriate comparison, I'm sure everyone is capable of doing some simple sums, but at the end of the day the IQ does 5.8L/100km and sacrifices little if anything in everyday performance.
Posted by: | 19 November 2008 at 01:14 PM
Everyday performance compared to a 4 cylinder, 3440lb midsize you mean. I don't doubt it would scoot around city streets just fine (low speeds and off the line acceleration are more greatly impacted by power to weight). Highway speed passing? Say a two-lane in the middle of TX with a speed limit of 55mph, person in front of you going 45 and you wish to pass quickly enough to avoid on coming traffic...
Posted by: | 19 November 2008 at 01:53 PM
100 KM (62 mi) using 5.3L (1.4 Gallons) nets 44 mpg, no? That's okay, barely, I guess. My 2001 VW Golf 1.9L diesel is getting 54 mpg running biodiesel with yesteryear diesel injection technology. Somebody wake me up when there's some exciting news...
Posted by: Marshall | 19 November 2008 at 02:28 PM
Nice stuff, I am surprise by the choice of 4 cylinders rathe than 3, with 3 you have less frictions and thermal losses, shorter then more rigid crankshaft, anad less parts means less cost of manufacturing. too bad they didn't include the regenerative braking alternator they would have save 5more %. Next step is variable compression ratio and zero lateral component crank system for less friction, they would slash 10% and reduced even more the volume.
Posted by: Treehugger | 19 November 2008 at 08:34 PM
Isn't that little engine just adorable in that pic!? I saw it and said "awww...look how little!"
I want one!
Nate H.
Dover, Ohio
Posted by: Nate H. | 19 November 2008 at 11:05 PM
This topic raises some questions for me, perhaps others may be more informed.
Compared to the Toyota Echo (Yaris)
The Echo weighs in at 923kg gets 0-60 in 8.5secs
The Auris weighs in at 840Kg and gets 0-62mph in 13.1 secs ?
Since Auris has the six speed gearbox, where did the performance go ?
Comparing the output of both these engines at 6000rpm.
The 1.5L 1NZ-FE gets 108Hp with 75mm x 84.7mm B & Stroke
The 1.33L 1NR-FE gets 100Hp with 72.5mm x 80.5mm B & Stroke.
Since power is proportional to bore radius, the reduced bore of the 1NR-FE should yield 101Hp. OK, the 100Hp they specify is close enough ! So then what's new ?
The fact that the 1NR-FE is achieving the expected performance (with the reduced bore) but doing it with a smaller stroke means that the maximum BMEP has been allowed to increase by up to 5% to offset this (84.7/80.5=1.05).
Simply put, compared to the earlier single VVT-i 1NZ-FE, Toyota appears to be running this new engine with a higher piston pressure but with a lower maximum piston speed.
Durability issues usually arise when piston speeds exceed 20m/sec so this 16.1m/sec is well within that boundary at 6000 rpm.
But then what's so special about this fixation of maxxing out at 6000 rpm with Toyota engines ? I would expect the allowable max rpm with an 80.5mm stroke to be much higher. That would give commensurate more power, after all, isn't that something to take advantage of when going to a short stroke engine ?
What am I missing here ? Is this limitation imposed to preserve clutch durability for those motorists who would be inclined to upshift beyond 6000rpm if they could ?
Finally it was stated elsewhere that an engine from the new "R" family would be going into the GenIII Prius. I assumed they meant the 2ZR-FE 1.8L Corolla Engine which doesn't make much sense for fuel economy. This new 1NR-FE, with the stop/start mechanism omitted, would look to be a more suitable candidate. I'll guess we'll all know in January.
T2
Posted by: T2 | 20 November 2008 at 11:59 PM
Limiting redline to 6000 RPM also limits the forces in the valve train and the required strength of the valve springs. That cuts friction losses.
Posted by: Engineer-Poet | 21 November 2008 at 07:25 AM
E-P, so what your saying is that they have taken a trade-off to minimise camshaft/cam friction at normal running rpms by the use of weaker springs which would then be conducive to valve bounce above 6000rpm.
So Toyota is not using cam rollers ?
I made an error in the earlier post. It should have read -
Since power is proportional to bore radius squared
T2
Posted by: T2 | 21 November 2008 at 08:23 AM
in belgium we will have to wait a few mouths before we can try ( test drive ) the new auris with this engine
6 speed is better for me
but will this engine have enough torque
to pull a small trailer ?
Posted by: dirk viroux | 01 December 2008 at 12:45 AM