Mazda has used direct injection in the SKYACTIV engine since worldwide 2012 and they don’t seem to have problems with it.
@jtsanders
Exactly, it’s only been 2 years
On many new technologies, it takes a few years longer for problems to become evident
We are going on 4 years, actually
I think all DI engines would state that they require top tier gas to keep the valves cleaner. Not a big deal I guess, but hints to a potential problem. I had a Focus with DI and sounded a bit like a diesel. I would just like to see if they are still good at 200K miles. Tested and true is always a safer bet, all the gas savings would probably not pay for a valve job.
Toyota which is interested in keeping it’s third world market in tack and reputation for reliable cars remains near last in the use of this technology. They have put their money into complicated hybrid technology instead of making turbocharging and direct injection the norm over their entire fleet like Mazda and Ford. Their engines are quite modern in nearly every other respect except with the use of direct injection. But, now that Honda uses it to sell a 40 mpg highway standard in the nearly full size Accord, they have to do something…
One caveat is that the intake valves DO tend to get deposits on them. With port injection, the fuel/air mix is keeping the valves clean. (at least if you don’t use gas from the dollar store) With direct injection, you’re relying on clean gas, heat, and good luck to keep everything clean.
DI can play with fuel timing so it can add fuel prior to valve opening.
Last week Lexus announced it’s fourth fuel system related recall on direct injection vehicles (IS, GS, LS). The latest, a potential for fuel system leak is likely caused by the corrosive effect of ethanol.
Ethanol has been a manufactures nuisance for many years. The 1981-1983 Chrysler Imperial employed a unique fuel injection system but in real world use failed due to ethanol clouding the fuel flow meter lens. Thirty years later we are still trying to adapt to ethanol.
Lexus has been addressing the misfire problem on the IS250 for seven years. The source of the problem appears to be the carbon build-up on the intake valves. The 4GR-FSE engine does not have cold start injector to clean the engine oil from the intake valves. The latest fix is to install updated pistons and rings in a effort to reduce blow-by oil vapors in the intake manifold. It seems 3 out of 4 cars have an intermittent misfire problem, I usually see 3 cars a week in the shop receiving new pistons.
With respect to “we’ll see in ten years”, if we can ignore the first ten years let’s also ignore turbo chargers from the 1980"s. That wasn’t impressive, the future looks bright.
Most manufacturers stopped using cold start injectors years ago, I seem to recall
"Most manufacturers stopped using cold start injectors years ago, I seem to recall "
Yeah, the last one I saw was on an old Toyota Cressida. There was a single one in the intake plenum. I don’t see how it would have had any more beneficial effect on intake valve deposits than does port injectors.
The port injectors on the 2GR-FSE engine are used during cold start operation. The 4GR-FSE engine doesn’t have port injectors, there is one cold start injector in the intake plenum but is is ineffective in keeping the intake valves clean.
The manufacturers most in need of CAFE improvements are most likely to invest in DI. Toyota is in much better shape than most makes. And they intend to offer hybrid versions of most/all their vehicles, which gives even bigger gas mileage gains.
The gasoline motor is reaching a point where efficiency increase are slight while the measures to achieve them are more complicated. FI simplified fuel delivery…getting rid of the traditional distributor did too and each made for reliability increases. Now, we are adding technology like turbos and direct injection which decrease reliability. IMHO, I will wait to buy a direct injected car like I have with CVTs…till they have been trouble free fir ten years…the average time I try to keep a car.
Dag, I too feel that direct injection gasoline engines need a decade of proven reliability before I’ll feel comfortable with them.
But, alas, if I need to replace my current car at some point I may have no choice. The constantly more stringent CAFE and emissions requirements may force it onto all new cars in the very near future. Even with all manufacturers (including supercar makers) turning to EV-based hybrids backed by small turbo (or super) charged engines, direct injection may become part of the equation. Little tiny direct-injected turbocharged engines keeping the battery packs from leaving us stranded when they run out. The little engines may even start on their own when we park and run for awhile to top the batteries off. We’ll be having lunch at a highway stop and the car will be sitting in the parking lot charging itself. You know what, the more I think about the idea the more I like it. Why haven’t manufacturers thought of this?
They have, mtnbike, but current batteries have to be big, expensive, and heavy (like a Tesla) to manage a purely electric drivetrain, which is what you need if you only have a small engine to keep the batteries charged. BMW is doing essentially that with one of their electric models. It can be used purely as a rechargeable electric, but there is a small, optional gasoline engine that fits in a compartment at the back and can be used to charge the batteries. It isn’t powerful enough to use full-time as a normal hybrid, but it can extend the range a bit and maybe keep you from getting stuck.
As batteries improve we’re very likely to have hybrids with small engines that are just big enough to keep the batteries charged, with the cars running off the batteries. GM claimed the Volt didn’t run off the engine directly until others showed that at times it did. They hemmed and hawed before admitting that it sometimes did (its drivetrain is similar to that of a Prius).
But, Mark, do these cars have a switch you could flip to direct the little engine to start automatically to charge the battery and shut down when it’s fully charged while you’re having lunch? Without, of course, enabling the other systems in the vehicle such that someone could drive off with it. That’s the function I was referring to.
@Thesamemountainbike as an “old Toyota” owner you can appreciate this reasoning perhaps. (Not “old” Toyota owner ;). )
So, I was looking at the stat sheets for the direct injection four and six in the 2015 Colorado before I decided to pull the plug an an 10 year old proven tech Toyota and not wait for them to “catch up”.
Four cylinder torque for the four cylinder between the two, the same
Six cylinder torque numbers, the same
Highway mileage and city mileage difference on four wheel drive, fewer then 2 to 3 mpgs
The horsepower does weigh heavily on the side of the direct injection but cruising at speeds higher then 80 mph is not where it is at in these trucks and that’s where this difference is most apparent.
The biggest difference between the two is found in the transmissions available which account in big part for the mileage difference. So, which am I going to buy ? It was obvious. The direct injection could be a negative to get a better interior. Hmmmmm.
The Volt does run directly off the engine as a fail safe condition, much like a limp mode. Under normal circumstances, it is used to recharge the batteries after exceeding the 38 mile (or so) battery limit. I think GM deserves some credit for providing fail-safe modes to keep the car moving until it can get to a safe place to stop. They had a totally new to them technology that they wanted to deploy, and this solution helped give them confidence that the car was ready for prime time.
Under “normal” conditions, like the Prius, the Volt runs off both battery AND the gas motor and does not have to wait for battery depletion. There are some modes when driving that are most efficient if the actual drive is done by both the electric and gas motor. The difference between the two (Prius and Volt) is the size of the battery and the larger electric motor in the Volt which allows it to run on a different regime then the Prius. Bottom line though, the Volt has dependency well beyond charging and fail safe for the gas motor. Plug in hybrid is a better way to describe the Volt. It just doesn’t sound enough different to warrant the loan money they got from the govt.
Acknowledging that the electric drive is much more dependable then a gas motor, it is the other way around. When the gas motor fails to start, you can at least drive slowly, till the battery runs down and/or you get to another outlet. That is not a new idea on the Volt. Much of the battery only priority was gleaned from the EV1 work and the concept efficient gas power was adapted to it. . No one really re invented the wheel. They just did a real good job of selling it…but not cheaply enough.
Battery improvement will only change the length of time/distance that an electric motor can run, it will never replace the idea that if a gas motor is used to charge the battery instead of solar cells or renewable resources, it will always be more efficient to drive the car with both the gas motor and the electric motor at times…especially hill climbing while the motor can still be used to charge the battery at the same time. It’s just mileage between the charging stations and how fast the battery can be charged that will determine when plug in hybrids become obsolete. Until then, gas motors will help electric motors drive their cars…