Advanced Controls Working At the Car Wash

January 8, 2007

7 Min Read
Advanced Controls Working At the Car Wash

Drive-in car washes may not seem like they need more automation. Once your car is on the conveyor, you don’t need to lift a finger as it makes its way through the cleaning stations. But the people who pay the utility bills and process payroll for automatic car washes know they’re not nearly automated enough.

The dirty little secret about these car washes is that they just aren’t as efficient as they could be. It’s not that they don’t reclaim the wash water — many do. It’s that they have poor position control of the car within the tunnel, so cleaning stations end up spraying chemicals and water before and after the car passes though. “Every time the system applies soap and water to the air, it’s wasting money,” says Mike Gammons, operations manager for National Car Wash.

Then there’s labor cost. Gammons says a typical automatic car wash would have as many as six workers running the conveyors and filling the fluids. “If you want to reduce labor costs, you need to become even more automated,” he says.

National had strong motivation to get rid of these inefficiencies. So last year, the company paired with Schneider Electric’s applications development group to come up with a new car wash control system that uses modern automation technology to increase efficiency.

National isn’t the only company working in that direction. To take one prominent example, Germany’s WashTec AG, which has a U.S. subsidiary called Mark VII Equipment, has a patented system in which the brushes and rollers track the movement of the car as it moves through the tunnel. The system employs microprocessors to control not only that movement, but also the pressure of brushes by monitoring the power consumption of the roller drives. In September, the company rolled out a 3D laser scanner that measures the contours of individual cars — right down to protruding mirrors — and then adjusts the washing stations accordingly.

Despite this high-tech fringe, car washes for the most part still have plenty of room to improve from an automation standpoint. “Many car washes are still primarily mechanical systems,” says Ian Hitchins, Schneider Electric’s director of applications and solutions. But the market is sizeable.

The U.S. has 102,500 car washes that generate $23.4 billion a year, according to Mark Thorsby, executive director of the International Carwash Assoc. About 40 percent of these are coin-operated, self-serve installations. Another 40 percent are stationary automated models, those where the car stands still while the washing equipment moves around it. The remaining 20 percent are conveyor models of various kinds.

Car washes have a lot in common with other types of specialty machines created for niche applications. Hitchins believes the kind of automation upgrade undertaken by National could also help a variety of industries with similar efficiency problems. “There are a lot of purely mechanical machines that can benefit from electric technology,” he says.

Controlling the Tunnel

National’s automated system, called the “Tunnel Commander,” consists almost entirely of Telemecanique components — including a Premium PLC, eight Altivar variable speed drives and TeSys U-Line motor starters for the car wash’s 13.5-15-HP motors. Lighting and gate controls are provided by Telemecanique’s Phaseo power supplies and Zelio relays. All told, the system has 64 inputs and 64 outputs. An industrial Ethernet network ties everything together.

These components run the car wash’s two primary subsystems. The first is a motor control center whose motor starters have the ability to report the status of all motors and starters through an Ethernet connection. The second system controls the car wash blowers, which have variable frequency drives. Contrast this setup with the control systems found on earlier, entirely mechanical car washes. “It’s usually just a NEMA starter motor with no feedback whatsoever,” says Gammons.

One of the main advantages of the Tunnel Commander is positioning accuracy. Gammons says the new motor control system, with the help of photoelectric sensors that track the passing of each vehicle’s bumpers at key points in the tunnel, can in theory position cars in the tunnel within 1 inch of one another. He adds that the sensor and control technology are based on Schneider conveyor controls that offer positioning accuracy within 1/10-inch.

Traditional car wash control systems also use photo detectors at the entrance to the car wash to sense when cars have entered the tunnel. With that data they can trigger all the cleaning stations. But Gammons notes these systems lack the fine position control because they get no feedback from the motors. For that reason, he adds, the spacing between the conveyor dollies that carry the cars through a traditional wash is usually 42 inches.

Positioning accuracy can have a big impact on a car wash’s bottom line. It allows the cleaning and drying processes to fire only when a car is truly in position. Applying soap and water to air for a brief time before and after each car passes may not sound like a big deal, but Gammons estimates this unnecessary spraying costs, for a typical car wash, about $20,000 to $30,000 per year. The tighter control of car position also increases throughput. And at 120 cars per hour, the Tunnel Commander has about twice the throughput of older automatic washes, Gammons says.

Another big economic boost comes from the variable speed drives used for the system’s blowers, another feature that would not be found on a typical car wash. Gammons says they lower energy consumption by about 33 percent.

Monitoring On- and Off-Site

Tunnel Commander also takes a more advanced approach when it comes to the data it makes available to operators. The system’s command center is built around a 15-inch touch screen industrial PC that allows operators to access all the car wash functions. The display is animated, graphically showing each car moving through. And aside from car positioning, it also allows operators to control lighting, doors and more. The same system also displays diagnostic information from the PLC and monitors fluid levels throughout the car wash.

What’s most remarkable about the system is managers don’t need to be on-site to see what’s going on. The system uses Schneider’s Transparent Ready technology, which offers remote Web-browser access to automation systems. With the Tunnel Commander, remote operators can receive reports on the number of cars that have passed through the facility in a given time period, what type of wash they purchased, amount of revenue generated, whether there were any faults in the system and corrective action taken, and even when employees punched in. The car wash can be monitored from a troubleshooting perspective too, with reports on fluid levels, system faults and corrective actions.

According to Gammons, the on-site and remote monitoring together can reduce labor costs dramatically — from six workers usually down to one.

So far, National Car Wash has built two Tunnel Commander washes in Tennessee. But expect to see more soon. Since the system’s development, Auto Data Inc., one of the leading software providers for the quick lube industry, has bought the rights to sell Tunnel Commander systems. “Many quick lube businesses also run a car wash, so the technology is a good fit for us,” says Bill Schad, Auto Data’s president and founder.

And that fit isn’t just from a business standpoint. Schad sees potential to adapt some of Tunnel Commander’s technology to further automate oil change shops. Auto Data has a history of automating the oil change business. A couple of years ago, for example, the company introduced a scanner that reads VIN data from a car and calls up a list of relevant fluids and parts. Schad next plans to use Tunnel Commander’s underlying architecture as the basis for a PLC-based system that monitors a quick lube shop’s oil tank levels. The system could run as part of Tunnel Commander or as a stand-alone version for sites that lack a car wash.

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