Lexus Develops Toyota’s First Cylinder Deactivation System – Next-Gen Tundra
Tim Esterdahl | Mar 25, 2014 | Comments 16
UPDATE: Looks like our source for this information, Motor Trend, got it wrong. The RC F won’t have cylinder deactivation. Instead it will use the Atkinson Cycle at lower loads.
This innovation is essentially variable valve timing, as the intake valves are left open a little longer at lower loads. The fuel savings is equivalent to reducing displacement 15%, yet power is unaffected.
Seems like this tech could work on any V8 if the engine was designed for it…
Next month at the North American International Auto Show in Detroit, Lexus is supposed to reveal its new Lexus RC and RC F coupe. While the news isn’t that exciting for truck fans, one nugget stood out. The RC F coupe will offer a Lexus and Toyota first of cylinder deactivation. Yep, Lexus is going to offer it. Here’s why and what it could mean for future Toyota products.
Lexus is reportedly going to offer cylinder deactivation on its new RC F coupe, will other Toyota models follow suit? Photo Source: Carscoops.com
The Lexus RC F coupe is a track-ready sports car that will compete with the many of the other top production sports cars in the world. It will have a 5.0L V-8 capable of generating 455-hp at 6800 rpm and 401 lb-ft of torque at 5200 rpm. In other words, it will go fast, very fast! It is expected to reach top speeds of more than 186 mph according to MotorTrend.com.
While that is cool and all, the RC F is expected to have some tweaks to meet the very strict Euro-6 emissions regulations. Apparently that is where cylinder deactivation comes in. MotorTrend says; “To achieve that, the RC F will incorporate Lexus’ (and Toyota’s) first-ever cylinder deactivation technology in which four cylinders will be shut down during high-speed cruising.”
This is the same technology that other makers have notably used with mixed or bad results (like GM’s oil sucking issue.)
We reached out to several sources to question why they would use cylinder deactivation at all. Seems a bit odd to us that cylinder deactivation could be tied to emissions control. Here is the best response we got:
Chevrolet has been doing this for quite a while. It’s also becoming common in diesel engines in Europe. Most of the Euro-6 requirements are in regards to CO2 and NOx emissions, both of which are higher at higher RPM (which are often sustained at highway driving). The choice is to either add more gearing to reduce RPM, add more EGR/scrubbing, or use cylinder deactivation to reduce fuel use. Gearing adds weight and complexity, EGR and scrubbing causes efficiency losses, and deactivation hits somewhere in the middle. So it’s a choice of what you want to accomplish and then finding the cheapest solution to that problem.
While it makes sense to emit fewer CO2 and NOx emission particles at higher speeds, we wonder wouldn’t a multi-speed transmission get the same net effect (see: Ram’s 8-speed transmission).
It remains to be seen if Lexus will really offer this plan. If they do, we will be right there in Detroit with our questions on emissions and cylinder deactivation.
All of this brings us around to the BIG question, with Lexus planning to develop this system, will it get passed down throughout the lineup. Point blank, will a next-gen Toyota Tundra offer cylinder deactivation in an effort to curb fuel economy? That is the big question.
What do you think? Is this a sign of things to come or a one time deal?
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Filed Under: Auto News
I would go the 8 speed tranny over cylinder deactivation. Maybe asking for trouble that way.
I agree with Mickey on that. Cylinder deactivation just seems like a really bad idea. It takes the same amount of power and fuel to move a vehicle at a constant 60mph whether you are using 8 cylinders or using 4 and dragging 4 dead ones along for the ride.
I remember Mike Swears mentioning that they looked at it for the 2014 Tundra but decided against it. It could still be something they look at down the road but I wouldn’t expect it anytime soon.
I agree with the folks above, we’ll see an 8-speed tranny in a year or two on the Tundra giving it that 1-2 mpg increase to better compete
DJ,
I remember standing in front of Sweers when he said it. LOL! I think he is going to be forced to do somethings in the near future to meet consumer demands for innovation that he may not “love.”
Hello, send an email to editor@tundraheadquarters.com
First turbos and now cylinder deactivation? Toyota playing catch up, or just pulling aleady designed technology off the shelf in Japan? Curious to see what they do going forward, and why it took so long to release.
Brian J,
I thought the same thing after writing these articles and it was just dumb luck that both stories came out at the same time.
-Tim
Yes, it may be true that the technology is current now, but consider this: both Honda and GM have had oil consumption problems with cylinder deactivation (CD). Second, CD coupled with direct injection can make CD a real option (each cylinder is much more productive with GDI). This is GM’s third attempt. First in the 70’s and early 80’s I think. Second was earlier this century with not so good results. Third is now and it may be a charm. So, why not wait and observe?
A turbo in gasser truck…Hmm, ecoBoost. Some love it and believe in it while others are saying “I told you so” about the reliability and quality problems. So, the jury is still out on that one.
I’ll just pay off my Tundra and keep it for as long as possible. Once paid off, the price of gas will not concern me a bit.
I hope Toyota gets this right. I know from talking to various people within the auto industry that GM is having big problems with their cyl. deactivation reliability/dependability.
8 speed automatic transmissions
automatic lockup clutches (locking torque coveters)
high pressure turbo charged gas motors
variable valve timing
cylinder deactivation
automatic grills controlling radiator air flow
electronic traction control
( which prevents my car from going up my snow covered driveway)
anti-lock brakes (which I never activate)
140 dollar keys
140 dollar tire pressure radio transmitters
diesel DEF systems
diesel particulate burn off systems
all why I gave up new stuff and got a 7 years old diesel truck. Buy into all this stuff and just wait for the repair bills to roll in.
Toyota needs to keep it simple, low cost and keep it working.
The benefit of cylinder deactivation is less pumping losses. If they use variable lift system that they have in other Toyotas/Lexus cars, they can eliminate the throttle and not have to worry about cylinder deactivation.
I glad Toyota is going with the ability to switch to Atkinson Cycle instead of cylinder deactivation. I know that hypermilers like to invoked “Super” atkinson mode at “highway” speeds on their Civic hybrids and Prius to get crazy mpg in 70 to 90 range.
http://www.cleanmpg.com/forums.....hp?t=14295
I would agree but how would they do it? We would be talking about variable intake on all 8 cylinders. Not variable valve timing, that is just advance and retard of the start of open and close but rather changing how long the valve stays open. Kind of like 2 intake lobes which can move independantly which could increase duration.
I don’t know how the cam could do such a thing. If others have seen anything on how this can be down I would love to know about it.
If it’s possible to dynamically change the lift profile we can cut a 5.4 liter engine down to perhaps 4.5 when we only need low power to cruise. I really don’t know how they could do this since cam duration is fixed with the grind on the lobe. With cylinder deactivation we take the 4 larger displacement cylinders out of combustion and run on the other 4 which close the intake after some of the air has been pushed out. We cut the engine size by more then half.
This is too complex for my money but, I would have a lot more faith in Toyota getting deactivation right then Ford or GM. Ford can’t even keep spark plugs in the cylinder head and GM is having trouble with something as simple as the ignition switch.
I don’t think they would need to mess with the duration, just close the valve later.
Well if anyone can pull this off in a truck it will Toyota. Toyota is the “one” company that has proven they can do this as they first brought this concept to market in 1997 for modern day power trains.
http://en.wikipedia.org/wiki/Atkinson_cycle
Not sure if toyota will follow GM’s deactivation, hope not I think just asking for trouble. Toyota, my opinion, really skimped on the 2014 tundra not offering as standard or options on the SR5 equipped tundra at least 6-7 things from prior 2013. In order to remain competitive, the tundra has to so something drastic in 2015 to make up for the ho-hum redesign cosmetic ONLY like 8 speed tranny or offer more options.