Without a single ounce of government intervention, the aftermarket could help the Canadian car driving public save more than 100 million liters of gasoline a year. The answer is as simple as a tune-up.
According to data gathered as part of British Columbia’s AirCare emissions testing program, emissions repairs were responsible for an estimated 23 million liters in fuel savings in the first five years of the program. While that analysis is already nearly four years old, it shows a clear connection between fuel consumption, emissions and the state of tune of an engine.
Subsequent data shows the same basic result. Analysis from Ontario’s Drive Clean program shows even greater savings.
That correlation is brought into sharp focus through additional breakdowns of data done by AirCare’s chief analyst, Steven Stewart. He is, according to other personnel at inspection/maintenance (I/M) program management company Pacific Testing Technologies, “the man who has the data and knows how to cut it.”
“This is certainly not a simple issue,” says Stewart. “Some repairs make (fuel consumption) worse, some make it better, but it’s certainly not always the case.”
The AirCare program only affects the vehicle population of the region surrounding Vancouver, B.C., referred to as the Lower Mainland. At the time of the study, this included a population of one million vehicles.
The data from AirCare shows an overall average improvement of 2.26% in the fuel consumption of light vehicles when they have had successful emission repairs, which equated to four million liters in year five of the program. Assuming that the vehicle population in B.C. is not materially different from that of the rest of the country, a similar state of repair in Canada would return a benefit of 60 million liters.
If one wanted to use Ontario’s Drive Clean program estimate of seven million liters in savings after its first 800,000 vehicles were tested, that estimate would rise to more than 130 million liters of gasoline saved.
It is important to note that emissions testing programs don’t focus on fuel mileage as a benefit. They are concerned, naturally, with measuring emissions. Improved fuel mileage is an added benefit. It is also useful to recognize that no emissions test can lower emissions; it can only confirm what’s coming out the tailpipe. Conversely, just because a vehicle population exists outside an I/M program area does not mean that it has better–or worse–running vehicles. It’s just that without the measurement regime, you don’t know which are which.
Data from virtually every I/M program in existence points the finger for emissions programs firmly at conventional tune-up items. Spark plugs and wires consistently rise to the top of the list of components replaced to achieve successful emissions repairs. In the current generation of vehicles, oxygen sensors now top the chart.
The Burning Question
What has become increasingly apparent as the vehicle repair industry learns how to deal with emissions testing programs is how emissions repairs have little to do with just replacing emissions components, and how much it’s really about obtaining proper combustion.
Rich Keller, director of engineering for ignition products, Federal-Mogul Corporation, says that this is an important point.
COVER STORY
COVER STORY
“A tune per se doesn’t necessarily do anything for fuel consumption, unless there is something wrong with the engine.” For example, he says, to get any benefit from replacing the air filter, the old one has to have been dirty. “On the ignition side, if you need it you have to have had some level of misfire, in which case you’re robbing power and wasting fuel.”
While the overall fleet average of fuel savings may seem almost insignificant on a percentage basis, the performance improvement in individual cars can be dramatic, as much as 10%, with a proper tune-up. The problem is that consumers seldom know there is a problem.
“On a micro scale, if you have a six-cylinder engine, you may not even notice it. On a four cylinder you would. But if you have a consistent misfire, you’re robbing a large percentage of the power by not hitting on every one of the power strokes.
“It can depend, if you have a consistency of the misfire, one in six or one in eight, that’s pretty significant.” It’s seldom so consistent, though. “On wet days you can have big problems, a miss in every one, two or three strokes, but find that on dry days it’s not really an issue.”
Just because it’s not readily apparent to the consumer doesn’t mean the problem doesn’t exist, though. By the time a driveability problem has revealed itself to the driver, combustion integrity has deteriorated severely.
The issue with emissions and tune-up can be explained by looking at three levels of measurement, says Keller. “What you’ll see is three levels of measurement. In a lab environment, where you have very sensitive equipment, you can see changes with very small adjustments. You can evaluate the quality of each individual burn.
“The next level is the standard emissions testing. It will show you a gradual degradation in the quality of combustion. All sorts of factors fall into whether you’re actually making a good combustion process, but that shows you something is not quite right.
“Then you have the bottom level, which is seat of the pants.” He says that it’s not unusual for consumers to be completely unaware of a consistent cylinder misfire, especially on a V8 engine.
“It’s my experience that on a typical V8, somebody could be missing a cylinder fairly frequently, and still not notice. Especially if they’re not really thinking about their car.”
In terms of percentage, a 100% misfire on a single cylinder in an eight-cylinder engine translates into a 12.5% reduction in fuel economy. The same situation on a six cylinder engine equates to a greater than 16% reduction in fuel economy.
Worse Than You Think?
I have personal memories of a 1978 Buick Le Sabre being tested during an I/M pilot program. The vehicle, which had been through the repair mill once or twice without success, had an exhaust stream hydrocarbon reading of 200 grams per mile. Fractions of a gram per mile–maybe even creeping into the single digits–are generally considered acceptable. At the time, the techs in the testing center and I joked that you could run a car on the amount of unburned fuel that was coming out of the exhaust pipe. The car ran poorly and smelled like a refinery. It was a rolling justification for I/M programs and what people often think of when they consider a car that’s running rich or pouring unburned fuel into the exhaust stream–obvious evidence of a gross polluter.
It’s also a rare occurrence, particularly on vehicles equipped with electronic fuel injection.
Nevertheless, pouring unburned fuel into the exhaust stream is not only wasteful, it is also destructive. One side effect is extremely high catalytic converter temperatures as this device seeks to break down, or catalyze, the fuel. This can drastically shorten the life of the catalytic converter–causing its inner structures to literally melt together–or worse.
“The other situation is that you can set leaves and grass on fire. You’ll end up cooking whatever you are parked on; you may end up cooking the whole car,” says Keller.
Chuck Ruth, Robert Bosch Corporation, agrees that much work needs to be done on the impact of failed emissions items on fuel consumption–particularly regarding OBD II vehicles–but does not doubt that there is an affect.
“We have an internal company study (on pre-OBD II vehicles) that talks about a 10% to 15% increase in fuel economy when you replace a worn-out sensor with a new one. In many cases, the car is still running, but the oxygen sensor is slow or even dead. Slow is just as bad as dead in terms of fuel economy. A lot of times the consumer may not notice while driving, and if they don’t track their miles per gallon, they won’t notice that either.
“It’s one of those things that there is not muc
h awareness of on the part of the consumer and there is even a certain lack of awareness in the trade in terms of tracking it as routine service. You’re just waiting till the Check Engine light comes on.
“There are a lot of undiagnosed bad O2 sensors out there and if the car doesn’t go through some type of emissions test, it’s just not going to get caught.”
Information from Dana Canada calls the O2 sensor “one of the most commonly overlooked causes of many of today’s driveability problems.
“An O2 sensor that’s not functioning or not working properly can cause more than just higher emissions.” The company points out that failure to diagnose an O2 sensor problem can cause comebacks, premature catalytic converter failure, and higher fuel consumption.
Doug Morrison, technical service manager, NGK Spark Plugs Canada Ltd., adds that failure to use the proper type of spark plug can also affect the long-term success of a tune-up. “OEs always put in the double platinum,” which provides the kind of 160,000 kilometer life promoted. While there are a number of precious metal spark plug options in the market, he says he has noticed an increasing tendency to replace double platinum plugs with conventional designs that are not engineered for the conditions experienced in a modern engine, at least not for long by modern standards. “Then what happens is that the gaps open up extensively and the fuel consumption increases. Replacing like with like is really important.”
All these minutiae aside, the overbearing issue on many consumers’ minds is the cost of fuel. Consumers, quite frankly, don’t think about their cars much. Unless they’re in an area with an I/M program, they think about its emissions even less. But they do think about what it costs to gas up.
A Drop In The Bucket
Estimates floated with the public have pegged summertime prices in the $1 a liter range. They’re already reaching nearly 90 cents a liter in some localities. The problem, if it can be called that, is that demand south of the border has squeezed the supply surplus to the point where prices are being bid up on both sides of the border. As this is being written, gasoline prices in the U.S. are reaching record levels, over $2 U.S. a gallon in some areas.
It would be nice to think that saving more than 100 million liters of fuel a year–by getting every car out there that needs a tune-up to get one–would shift the demand curve and prices might drop.
It would be nice, but it’s not likely. Let’s consider that 100 million liters of gasoline for a moment. While certainly a lot of fuel by any personal measure, in terms of total fuel usage for the country it is just a drop in the bucket. According to the Canadian Petroleum Products Institute, Canadians use 30 times this much every month; Canadian consumption tops three billion liters a month during the summer, and less in winter, about 2.5 billion liters a month.
So, while the overall benefit is negligible, the individual benefit is not.
Money to Burn
Looking at the data gathered by AirCare, it is clear that in some modes of failure–high carbon monoxide for example–the fuel savings from a proper repair can be considerable. Expressed in terms of liters/100 km–just like the mileage rating on a car–some vehicles experience significant improvements. One such vehicle improved its mileage by 6 liters/100 km. If that person drove 15,000 km a year, the savings at today’s prices would be more than $700 every year.
A more modest improvement, say 0.5 liters/100 km, would still garner the car owner who drives that same distance an annual savings of more than $250 a year.
Stewart, who shepherded the studies, says that it’s important not to look with too much precision at the numbers, since the samples are relatively small–he hopes to get sample sizes into the thousands a year–but that on individual cars the benefits are well documented.
“I’ve seen a Tempo that had a bad oxygen sensor. Its fuel system’s strategy was to run rich all the time when that happens. We put a new sensor in, it established closed loop operation, and the emissions came down to a fraction of what they had been.”
The key for the aftermarket is to approach the issue of the tune-up in a different way from that imposed on consumers in I/M program areas.
“In the United States and in Canada, the only places where these programs are in place are the higher population centers,” says Ruth, “but you can bet your bottom dollar that every vehicle in Montana is behaving the same way.
“They’re getting the same pollution but the car population is so dispersed that it’s not causing a demonstrable pollution problem. You go to a place where you get inversions, where the air gets trapped, or if you just have enough density of vehicles, that’s where you have the programs and the measurement. But for sure it’s happening everywhere, it’s just not getting measured and it’s just not getting caught.”
“You can close your eyes and not look, but that doesn’t mean it’s not there.”
Stewart says that the benefits from addressing car emissions and fuel consumption across the board can be considerable. And, he adds, it is more readily achievable than changing people’s behavior. “If you wanted to get a 1% reduction in fuel usage within a group of 100 people, you could try and get one person to ride a bicycle all the time, or you could get them all to get their cars fixed. You get the same effect.
“It would be nice for the industry to get some credit for reducing fuel consumption. If you simply improve the fuel consumption by just a tiny bit you can make a huge contribution to greenhouse gas reduction.
“It would be nice for the industry to get some credit for that. Most environmentalists just want people to ride bicycles.”
