Some say a proposition in California to prohibit the sale of all internal combustion (IC) lift trucks below 8,000 pounds capacity after 2007 spells bad news for makers and users of those vehicles. However, one of the leading manufacturers of electric lift trucks isn’t counting its fuel-powered competitors out so quickly. Material Handling Management recently interviewed Tim Quellhorst, vice president of engineering at Crown Euipment Corporation. He has some strong opinions about some of the hype that’s been going around about the IC versus electric issue. — Tom Andel, chief editor, Material Handling Management.
MHM: Does this proposed change to the CARB guidelines shift the balance between electric-powered lift trucks and IC models?
Quellhorst: In the past, various events or circumstances have caused some to predict a pending shift from IC to electrics in the 4-wheel counterbalance lift truck market. Certainly, any new law that would prohibit the sale of IC powered vehicles would have that result. However, both the current manufacturers and the consumers of this equipment will likely strongly oppose this initiative. While I'm not an IC market expert, Industrial Truck Association (ITA) statistics would seem to support this conclusion. In 2002, Domestic Factory Bookings for 4-wheel counterbalanced vehicles (less than 8,000 pounds) indicated that only about 1 percent of electric 4-wheel vehicles sold were equipped with pneumatic tires whereas nearly 45 percent of the ICs were equipped this way.
MHM: What's the connection between IC power and pneumatic tires?
Quellhorst: I would assume that pneumatic tires are more important for outdoor applications where there's rougher, more uneven terrain. From what I know about IC powered vehicles, they likely have significantly more peak horsepower than an electric powered vehicle of equivalent capacity. This peak horsepower would be important for pulling out of depressions, climbing over debris, and other similar kinds of conditions. Also, this peak horsepower difference gives IC products a real advantage if heavy loads need to be frequently lifted at high speeds. So, even inside buildings where smoother surfaces allow for cushion tires, there are real market needs that electric products may not meet as well as IC products do, at least with the current state of the art.
MHM: Will AC power bridge the application gap between IC and electric lift trucks?
Quellhorst: From what I know about IC and AC technologies, I don't believe that AC by itself is a significant enough technology shift to bridge the peak horsepower advantage that IC products have over electrics. One would think that the state-of-the-art must be capable of meeting well-established market needs before the customer will "freely" accept a radical shift like the one being proposed by CARB.
MHM: Has all the talk about the promise of AC been overblown?
Quellhorst: AC technology does have its advantages. Crown offers it as an option on our reach family of products because, in certain applications, some vehicle operating characteristics can be improved enough for operators to notice a difference between an AC powered vehicle and one with more traditional DC power. While a lot of AC hype has centered around how AC can reduce maintenance costs since AC motors don't have brushes, we’re not sure that the end users have been educated on what components are added to the truck with the addition of AC. AC motors require electronic controllers that convert DC battery to AC. These motor controllers often need fans to keep them cool, and these components need maintenance too. In many market segments and, therefore, for many products, DC technology presents no real disadvantage and, in some cases, it is even more appropriate than AC.
MHM: Where does DC work best?
Quellhorst: An example would be lift systems found on three- or four-wheel counterbalanced lift trucks. For most customers, the most cost-effective solution is a series DC motor combined with a spool type hydraulic valve. No electronic controller is needed, just a line contactor used to turn the motor on and off. Raise and attachment speeds are controlled with the hydraulic valve. While an AC system will provide some efficiency advantage over this simple DC system, it isn't because AC technology is inherently more efficient but, rather, because an AC system must have a motor controller. Compared to an on/off type of system, one with a motor controller can better match the amount of oil flow to the functional need.
This is the real underlying reason for the efficiency improvement and can just as easily be achieved with a series DC motor controller. Since the late 1980s, most manufacturers were recommending an optional DC Lift control for applications where the customer frequently used attachments, including sideshifters. Basic misunderstandings like this have helped to cause confusion in the marketplace and has lead to an overstatement of the real opportunities and value that AC technology can provide.
MHM: Does this new buzz about electrics grow the opportunities for developments in fast charging and even fuel cells?
Quellhorst: Fuel cells do begin to overcome some of the disadvantages associated with large lead acid batteries and the associated equipment required for recharging them. Considerable fuel cell research is being conducted in our industry as well as other market sectors, like automotive and stand-by power generators. This could also be the origin of wider fuel cell acceptance rather than a new regulatory demand within the Lift Truck Industry. Fast charging seems to be most promising for those with larger fleets since it has the potential to reduce the number of batteries needed in 24/7 type operations. Because a charger is still required, it probably won't impact the IC vs. electric decision as much as a credible fuel cell might. Both of these seem to be a ways away yet, although it appears that fast charging might be slightly ahead of fuel cells at this time.
MHM: What are Crown’s R&D priorities in the near term?
Quellhorst: Crown will continue research for innovation in areas like cost of ownership, up-time, operator productivity, efficiency, operator ergonomics and acceptance. These have been historic strengths for our products and we see these areas as continuing to be of significant value to our customers.