Start Your Frigid Auxiliary
This Tip was provided by Clayton Boyd, owner of The Sweeping DoctorHere in the Chicago area it gets cold and stays cold for extended periods in the winter. When the temperatures stay down like that, starting a sweeper's auxiliary engine can become a difficult, sometimes impossible, task. If your sweeper can be plugged into electricity, then installation of a block heater is the best solution. If that is not an option, however, we came up with another way to preheat the oil in the auxiliary engine.
We do it by utilizing the exhaust heat from the chassis engine. As shown in the drawing, we cut a hole in the chassis engine's exhaust pipe after it leaves the muffler. Then a piece of 1-1/2 inch black pipe (with threads on the un-welded end) is welded around it. Then we added threaded fittings to route the pipe to where it finally exhausts 2 or 3 inches from the bottom of the auxiliary engine's oil pan, fastening the pipe securely everywhere along the route.
We install a shutoff in the system, since it only takes a few minutes of preheating to heat up the oil in the pan and it would add unnecessary heat wear to the auxiliary to allow the exhaust blast to continue for long. (Also, there needs to be a way to control the flow of exhaust air.) The shutoff is located at a spot in-line that can be reached conveniently.
Even in the coldest weather all it takes is 5 to 10 minutes of 'preheating' by the chassis exhaust and the auxiliary will start right up. The driver opens the shutoff when he starts the chassis motor. Then, after a few minutes of warming, closes the shutoff valve and starts the auxiliary engine.
Editor's Note: This is a Tip that really can be a help in extreme cold weather areas where it is not possible to use a block heater. However, it also requires some additional cautions:
Be sure to close the exhaust shutoff valve prior to starting the auxiliary engine. This is important for two reasons. For one, if the driver somehow forgets to stop the exhaust onto the oil pan, it can potentially cause overheating and premature engine wear to the auxiliary engine. Michael Fox, Project/Applications Engineer for Isuzu, said that this would be of especial concern with a gasoline engine, since the exhaust is much hotter. According to Fox, diesel engine exhaust only reaches around 300 degrees, but exhaust from a gasoline engine can reach 600 to 700 degrees.
The other reason to close off this type of 'exhaust heater' prior to starting the auxiliary engine is to keep the auxiliary engine from drawing in the exhausted air when it starts. Because it contains no oxygen this will cause an incorrect fuel-to- air mixture, as well as contribute to early plugging of the filter system.
Something to remember also is that once it is started, you should leave your auxiliary engine idling under most on-the-job circumstances. There are several reasons, including lengthening the starter replacement interval. Wisconsin also recommends that their engines be left idling to minimize the possibility of wiring problems due to condensation.
Thanks to Clayton Boyd for this Tip. Have an idea that would be helpful to others in the industry? Please let us know what it is.
