The steady increase in fuel prices is expected to continue into next year and beyond. For most small departments with two or three apparatus, this increase is hardly noticeable. For many large departments with bigger fleets of apparatus, however, the higher prices have stretched their operating budgets and left them looking for ways to reduce fuel consumption.

Among the hardest hit are busy urban departments with engine companies and ambulances that make hundreds of calls each day. The constant stop-start running through congested city traffic, coupled with prolonged idling in between, can eat up fuel at an alarming rate. Also hard hit are cash-strapped rural departments that frequently have to make long runs to handle fire, rescue and emergency medical calls over large areas. For these departments, and many others, fuel economy is a new concern that requires a new look at how they specify, operate and maintain their apparatus.

Here are seven steps to help you obtain better fuel economy from your emergency vehicles.

1. Match the engine horsepower to the load

   A lot of departments say they need big, high-horsepower engines, but very few take the time to determine how much power they really need. Even fewer consider how these engines affect fuel economy. Fuel consumption varies by the power, displacement and make of the engine. In general, higher-horsepower engines with larger displacements use more fuel per horsepower generated than smaller ones. They also tend to operate less efficiently when not running at maximum power.

   So how much power do you need? The average suburban pumper cruising down a level street at 35 mph probably uses less than 100 hp. Kick the speed up to 65 mph on an open highway, and the required power would be about 250 hp. Park it at a fire and pump 1,500 gpm, and the maximum power would still be under 350 hp. Most pumpers, medium rescues and heavy-duty ambulances can operate very well with engines in the 200 to 350 hp range. Smaller vehicles need even less power.

   Departments that require higher pump outputs, operate heavier vehicles or respond in mountainous terrain with steep grades may need engines with more horsepower, but they also will consume more fuel. The same applies to departments that have to run generators or other auxiliary equipment off the engine while pumping. The ideal solution is to consider all the operating conditions and select the smallest engine that still provides a good balance of power output, drivability and response time. When you specify your next vehicle, ask several apparatus and engine manufacturers for their advice on how to achieve good fuel economy and still meet your needs.

2. Keep the engine speed low

   This point often is overlooked, but it can make a big difference in fuel economy. Besides horsepower, another factor that determines fuel consumption is engine speed. Every time the engine crankshaft rotates, the cylinders take in fuel. If you reduce the number of engine rotations per minute, you also reduce the fuel intake per minute.

   For example, a lot of departments specify vehicles to cruise with the engines at the governed engine rpm — up against the stops. They figure that if the engines are running at their maximum rpm, drivers can't exceed the maximum intended vehicle speed. The problem with that approach is that the engines operate at an inefficient point and waste fuel. Instead, most engine manufacturers recommend cruising at engine speeds that are 300 to 600 rpm below the governed rpm. If departments want to restrict the maximum vehicle speed, they can have the engine electronics programmed to throttle back the fuel when the driver exceeds the limit.

   There are other considerations as well. Vehicle performance factors such as gradeability and shift points all depend on engine speed. The required input speed and power to drive pumps and auxiliary equipment also have to be considered. The best approach is to have the apparatus or engine manufacturer conduct an electronic analysis of all the operating conditions to help you specify the transmission ratio, pump input ratio, rear axle ratio, tire size and other factors to obtain the best engine speed. Each make and model of engine has its own power, torque and fuel consumption curves, so you will need to have a new analysis every time you consider a new engine. You will also need a new analysis if you want to change any of the other components.

3. Reduce the parasitic load

   The parasitic load consists of all the power that gets diverted to other components before it reaches the wheels. It's the power to run the alternator, air compressor, fan, water pump, air-conditioner compressor and other engine components. It's also the power lost to friction in the engine, transmission, rear axle and elsewhere. If you can reduce the parasitic load, you can reduce the amount of fuel needed to operate the engine.

   One of the biggest contributors to the parasitic load on emergency vehicles is the alternator. A high-capacity alternator running at full output eats up a lot of horsepower to supply current to the lights, siren and other electrical devices. One way to reduce the alternator load is to specify light-emitting diode warning lights, which operate at only a fraction of the current required by other lights and last up to 10 times longer. Another way is to use an electrical load manager that automatically turns off some of the lights and electrical devices when the vehicle is parked and the engine is idling. Ambulances and other vehicles that need to operate a lot of lights or maintain constant interior temperatures under extreme weather conditions while the engine is idling might consider using small, engine-driven auxiliary power units to handle the electrical loads without taxing the engine alternator.

4. Reduce the vehicle weight

   Vehicle weight has never been a big consideration for most departments, but the fact remains that weight is directly related to horsepower, which in turn is related to fuel consumption. Reduce the vehicle weight and you can improve the fuel economy.

   At typical response speeds of 35 mph or less, the primary factor in determining engine horsepower is the vehicle weight. Air resistance is only a minor contributor at these low speeds. For every percent you reduce the vehicle weight, you reduce the required power by a like amount. And once you reduce the vehicle weight enough, you can start specifying lighter axles, suspensions and other components, which will further reduce the weight.

   One way to start is to compare the weights of some of the major components before you buy an apparatus. For example, some engines weigh several hundred pounds less than others with the same horsepower and torque ratings. Some pumps are much lighter than others for similar flow and pressure ratings. And aluminum wheels can save hundred pounds over steel wheels depending on the number of axles. Individual weight savings start adding up, and some smart choices in the specifications can save a lot of weight before the vehicle goes into service.

   Another way to reduce vehicle weight is to split one general-purpose vehicle into two special-purpose vehicles and redistribute the equipment. A good example is running a light rescue and a pumper, instead of a combination rescue pumper. This would work especially well in departments that currently respond to a lot of motor-vehicle accidents and emergency medical calls with a full-size pumper. If you want to save fuel, shift the high-frequency calls to a smaller, lighter, more fuel-efficient vehicle. Another example would be for departments that cover both city and rural fire calls in pumper/tankers with a big-block engine. If they ran separate pumpers and tankers with mid-sized engines instead, the pumpers could cover the city calls without always carrying the weight of the extra water.

5. Train the drivers

   Some people might claim this is the most important item on the list. Drivers can have a tremendous effect on fuel economy, and even the most-efficient vehicle specs will not overcome the poor driving habits of bad drivers armed with red lights and sirens.

   An important part of that training is learning how to read traffic. This is a basic technique that allows drivers to anticipate and avoid problems around their vehicles as they move down the road. Reading traffic is part of defensive driving skills and also helps maximize fuel economy. It allows drivers to move through traffic more effectively and avoid repeated cycles of braking and then accelerating that can rob fuel economy. It also can help eliminate driver demands for high-horsepower engines that are commonly associated with aggressive driving habits.

6. Reduce the number of emergency runs

   This may sound like a controversial suggestion, but some departments already have implemented a priority system for calls to reduce the number of accidents involving emergency vehicles. Some calls get full emergency responses with warning lights and sirens, while others get non-emergency responses. This same system can help reduce fuel consumption.

   Here's how it works. Departments define which calls are serious enough to get emergency responses based on department policy, past incidents and legal counsel. Fires, smoke investigations, motor-vehicle accidents with injuries and most medical calls would require emergency vehicles to respond using warning lights and sirens. On the other hand, calls such as motor-vehicle accidents without fires or injuries, minor rescues, minor medical calls and general assistance would require emergency vehicles to respond with the normal flow of traffic without warning lights and sirens. Overall, this approach not only can reduce accidents, but also can potentially reduce fuel consumption by allowing less urgent responses for many non-emergency situations.

7. Perform regular maintenance

   Well-maintained vehicles generally get better fuel mileage than ones with problems. Engines run more efficiently, belts lose less power and tires roll with less resistance.

All emergency vehicles should be given regular preventive maintenance checks to spot problems and keep them ready to respond. Depending on the frequency of use, these checks should be conducted daily or weekly at a minimum. Departments need to define which components require checking based on the manufacturers recommendations and local operating conditions.

Among the preventive maintenance checks that affect fuel economy, proper tire pressure is critical. Tire pressure affects the rolling resistance, which is a key factor in determining how much power, and fuel, it takes to move a vehicle down the road. Low tire pressures increase the rolling resistance, decrease tire life and degrade handling characteristics. Tires should be inflated to match the required load pressure for each axle, rather than the maximum tire pressure.

Other things to check include malfunctioning components that affect engine performance or increase the parasitic load. Air and fuel filters with excessive inlet restrictions are good examples. Air compressors that run constantly and don't unload are another.

Reducing fuel costs is not easy. Sometimes it takes several changes over a period of time to achieve any noticeable reduction. Some things will work, but other things won't work or have more problems than they are worth.

Using cheap fuel is one pitfall to avoid. Diesel fuels that are high in sulfur require less refining and are often cheaper than low-sulfur fuels, but they pollute the air and can severely damage engines and ruin expensive emission control systems. Red “farm” diesel is the worst and should be avoided no matter how low the price. It's also illegal to use in any vehicle that operates on public roads, and can result in stiff fines for mis-use. Most pre-2007 diesel engines use low-sulfur diesel, and engines built in 2007 or later require ultra-low sulfur diesel. Many distributors have switched over to ULSD entirely because it can be used in all diesel engines, no matter how old.

Special fuel and oil additives that manufacturers claim will improve fuel economy usually won't work and should be avoided. This is something you should try and decide for yourself based on your individual experience. Balance the cost of the product with the cost reduction in fuel, if any.

Finally, trying to reduce fuel consumption by specifying more aerodynamic vehicles may work for long-haul truckers that regularly cruise for long periods at highway speeds, but the average emergency vehicle running around town isn't going to see any improvement at all. Aerodynamic styling may be attractive, but it won't make much difference in reducing fuel costs.

For departments that don't have a lot of money to spend to make big changes to their existing apparatus, the best way to lower fuel costs is to focus on the simple things. Train all your drivers to reduce aggressive driving patterns. Check tire pressures frequently as part of a regular maintenance program. Limit vehicle speed and keep engine rpms low when cruising long distances on the highway.

Making an effort to improve fuel economy now can result in savings in the future.

Storage Tips

Some departments store and dispense their own fuel for convenience or to obtain discount prices for bulk purchases. That can be a good way to save money, but there are some things to consider. Here are some storage tips to maintain quality and avoid problems.

Don't mix fuels

Diesel fuels need to be kept in separate tanks with separate dispensing systems. Mixing high-sulfur and low-sulfur diesel can contaminate the fuels, cause engine problems and result in hefty fines. If you switch from low-sulfur to ultra-low-sulfur diesel, drain and wash the interior of the storage tanks and dispensing plumbing to remove all traces of the old fuel.

Limit storage time

Unlike fine wine, fuel doesn't get better with time. In fact, most fuels actually get worse. Refineries formulate fuels with only enough stabilizers and inhibitors to maintain fuel quality for a month or so. In most cases that is sufficient because the average time from the refinery tower to your fuel tank is only a few weeks. Fire departments and other low-use customers that store fuel longer may find the fuel breaking down into longer hydrocarbon chains that can clog fuel filters. They may also experience growth of fuel-eating microbes that form a slimy mass. To counter these problems, departments may have to use fuel additives and change the fuel pump filters often.