For the past 40 years, Arvin Mueller has marched to the beat of a General Motors engine.
In 1960, Mueller was hired for the experimental engineering staff at Chevrolet, and on Aug. 1 he will retire as group vice president of GM Powertrain. During his career, he served as powertrain product team manager for the former Buick-Oldsmobile-Cadillac group; vice president of the Midsize Automotive Division; and head of the GM Technical Center. He moved to the head of GM Powertrain in 1997.
Mueller spoke with Staff Reporter Gail Kachadourian during a GM Powertrain press event in Irwindale, Calif.
Does GM believe it needs to convert all its engines from pushrods to overhead camshafts?
We have both because we feel that, depending on the application and the customer's desires, we can satisfy both kinds of customers if we have that variety in our portfolio. So there's no rule that we're more inclined toward pushrods or we're more inclined toward overhead cams. We pick the most appropriate technology that we feel fits the needs of the customer.
In our heavier truck applications we prefer the pushrod engine because it satisfies the torque requirements, reliability and cost needs of that particular market segment. In our inline areas, both in small cars and in light sport-utilities, we are using dual overhead cam inline engines in those applications because that technology most appropriately fits those needs.
And then we have the Northstar engine, a dual overhead cam, because of the needs of that particular market segment.
We clearly do not have a company preference for one technology or other.
Does pushrod or overhead cam better fit GM's fuel economy goals?
It depends on the configuration of the engine. In the V engine area, there's a couple of examples. One of the highest fuel economy V-6s in North American mid-sized cars is the pushrod 3.4 liter in the Chevrolet Impala.
That's a statement there. It's not a Honda or a Toyota, it's a GM pushrod engine. In the area of trucks, the best fuel economy in trucks is in GM's pushrod V-8 trucks, compared to other truck manufacturers who in some cases have dual overhead cam engines.
In the inline engines, on the other hand, the dual overhead cam technology is superior.
On an inline engine there's much lower frictional losses on a dual overhead cam versus a dual overhead cam in a V configuration just because of the difference in the number of components and the areas where friction needs to be managed. Focusing on the camshaft or the valve arrangement is a false way to make a determination of functional superiority. It depends on the design.
Does GM plan to introduce more overhead cam engines?
In the inline area, we have dual overhead cams on our new inline-four and inline-six series of engines. Our large V engines, the Vortec Vs, and the small blocks and the big blocks, those will continue to be pushrods.
And kind of down the middle, we have a small V-6 pushrod engine that we have at capacity at 4,800 a day, so that's a substantial capacity. The technologies are kind of bracketed. The inline engines are dual overhead cam.
The big truck engines are pushrod. We also have a pushrod V-6 in the middle and we will have dual overhead cam V-6 in the middle because that market is split between customers who prefer the technology of a dual overhead cam and customers who prefer getting the fuel economy advantage of a pushrod V-6.
What percentage of GM's powertrain budget is spent on r&d?
It's been the same over the past several years. We are re-engineering every engine we have and replacing several.
Our intensity on new products and upgrading our products is enormous. But we've been on that for the last three to four years. Starting in 1997 with the total redesign of the small-block V-8 engine. Since then, we've done the small block, the big block, we've added the Duramax diesel. We've shaken up the whole portfolio. The spending on that has been about flat over the past four years, but relatively intense.
Do you plan on more engines based on the Northstar architecture?
Northstar is used exclusively by Cadillac. We have capacity there to build more. It will be a function of how Cadillac sales for those applications that use that engine increase or decrease. We're prepared to build more if we need them. We have capacity.
Is the Northstar up for a redesign, and, if so, when?
It is - next year.
What do you want to change on the Northstar?
We'll go to variable camshaft phasing and lower friction components within the engine. It's basically a refinement of the engine.
What do you think the life span of these redesigned engines will be?
The traditional life cycle of an engine could be as long as 25 years. Going into the future, that won't be the case.
Product life cycles will become shorter because of the need to change the technology.
But that's not such an ominous thing anymore because of our use of flexible equipment. We can use the same equipment for a new product cycle.
It's not like a totally new investment each time we want to change the design. Product life cycles will be shorter. The cost of doing them will be less.
When does GM plan to introduce an inline five-cylinder engine and inline four-cylinder based off of its new inline six-cylinder engine in the compact sport-utilities?
Within the next few years.
What kinds of vehicles would these smaller inline engines be used on?
Smaller versions of trucks and sport-utilities that can't accommodate a six-cylinder engine.
Does GM eventually want to have one inline-engine architecture and one V-engine architecture?
No. We'll have five architectures that cover 90 percent of our capacity. That's our plan.
Will the Corvette always have a pushrod engine?
Yeah. The credible evidence is there that we can outperform any sports car in that class, and you start comparing some of the prices of the sports cars that we compete with, they're two or three times more expensive. So you tell me what the right technology is.
So is cost what drives keeping the Corvette engine a pushrod?
That's how we're able to sell about 35,000 of those a year. It's not cost; it's value. Do the right engine, get the right functionality and be able to provide it at a price the intended customer is going to afford.
Is GM working with Catalytic Solutions, as Honda is in Japan, to cut down on the amount of precious metals used in catalytic converters?
That technology won't satisfy the emissions levels in the U.S. Maybe it will be developed one day to do that. We're working with Catalytic Solutions, but right now that technology as it is developed today is only relevant to Japan, which has emissions laws that are a lot less stringent than the U.S.
Does GM use the same transmission you sell to Volvo on its own vehicles?
The one we sell to Volvo, that's our high-volume transmission, the 4T65E.
In some of the new Cadillac models, we'll be using the same transmission that BMW uses. It's already in the Opel, by the way. It will go into Cadillac when the new model comes out (in 2003.)
Is GM going to use an integrated starter alternator?
We have that under development. It will be part of the parallel hybrid truck, (which) has a flywheel alternator starter on it. (It) gives you a silent start and also the ability to coast without fuel.
Where is GM on fuel cell and hybrid development? How does GM plan to integrate those technologies into its engines?
We're working real hard on fuel cells because we believe that's going to be the technology of the future. That's the end game, we believe, fueled by hydrogen. On the way to that end game, we'll pass through a phase of using a higher penetration of hybrids. It's uncertain at this point in time how deeply the hybrids will penetrate and how long they'll stay as a strong alternative before fuel cells come on. Nobody knows this. It could be 10 years; it could be 20 years.
Where can we expect to see GM use more continuously variable transmissions?
It's in the four-cylinder class of vehicle. The Saturn Vue sport-utility is one application, but it could find its way into regular passenger cars also. As it stands right now, depending on how it's calibrated, it's a 5 to 8 percent fuel economy (gain), which is hard to come by otherwise. So it's a good functionality improvement for the price.
How does GM's purchasing engines from Honda affect GM Powertrain morale?
As long as you communicate to the organization as to why you're doing that, the morale isn't affected much at all. We're also selling Honda engines.
There's give and take. We sell them the Isuzu diesel and we think, aside from purchasing some relatively small number of engines, it's an opportunity for us to develop a relationship with Honda which will be a benefit to both companies in the future. So, it's really not about buying engines. We have plenty of six-cylinder engines. It's about developing a relationship and having an opportunity to exchange products.