Productivity and fuel consumption are highly dependent on factors such as site geography, including level or sloping ground, as well as material composition.
In addition, since a dozer predominantly operates at full power using its own weight, it is difficult to save on fuel consumption while working; however, there are a number of simple tricks you can use to optimise your production, while minimising fuel consumption.
In this article, we’ve used actual operational data from Komatsu D155-6 dozer to illustrate our points, but please note the fuel efficiency data shown here may vary depending on the actual work site, machine condition and operator skill.
1. Avoid high idling and/or turn off the engine
When waiting for a truck at the dump, for example, reduce fuel consumption by avoiding high idling whenever possible. If there’s a long wait between dozing work, turn off the engine altogether.
Use either your low idle option or depress the decelerator pedal to slow down the engine speed.
Komatsu’s test results (Fig 1) from adopting these practices show that:
» Switching from high idle to low idle for 30 minutes a day saves 1710 litres of fuel a year.
» Urning the engine off rather than using idle for a total of one hour a day saves 2430 litres a year.
2. Start working from the front of your dozing zone
The most effective way to doze on level ground is to shorten the distance you are pushing a full load by dozing "front-to-back" (in Figure 2, from point A to point B to point C).
Using this technique, start from point A, which is 3 to 5 m back from point X at the forefront of the dozing area.
After finishing dozing from point A, move further back in increments of 3 to 5 m each time to start a blade load.
This method increases the full load in the blade each time because you are establishing a downward gradient, plus it enhances productivity by keeping the digging ground even.
In contrast, repeated dozing from "back-to-front" lengthens the pushing distance and requires additional blade control (up/down operation) to prevent shoe slippage.
Consequently, the dozed ground easily becomes uneven, making it more difficult to keep a full load in the blade.
Compared with the "back-to-front" method, the "front-to-back" method can improve fuel efficiency (productivity per litre) by 11%, according to Komatsu figures (Fig 2A).
3. Doze on a downhill slope
Wherever possible, you can significantly improve productivity and enhance fuel efficiency (productivity per litre) by dozing on a downhill slope, using gravity to assist your dozing
Compared with dozing on level ground, downhill dozing allows you to dig and carry a significantly larger amount of material. Dozing time is also faster, leading to higher productivity.
While fuel consumption per hour is much the same, dozing a downhill slope of 7° increases blade capacity almost 20% compared with dozing on level ground and using the same engine power (Fig 3A).
Dozing downhill also harnesses the weight of the dozer, so you can expect greater efficiency, particularly from larger blades such as full-U blades. It may be less effective with smaller blades.
Further, reversing back up a 7° downhill slope in reverse second gear (R2) results in greater fuel efficiency than reverse first gear (R1). Although less fuel is consumed in R1, since the speed is also much lower, the dozer can travel approximately 20% further in R2 using the same amount of fuel (Fig 3B).
As a general observation, productivity is always much lower when dozing uphill since you are working against gravitational force. However, fuel consumption may not necessarily increase, simply because it takes longer for each cycle of dozing earth uphill (Fig 3C).
4. Other important factors
Avoid shoe slippage and stalling
Dozing or ripping while shoes are slipping or keeping the torque converter stalled will increase fuel consumption and cause irregular wear on your undercarriage.
Doze again in material where getting a full load is difficult
At sites where it is difficult to fill the blade due to hard ground or rocky material, reverse after the first pass and doze in the opposite direction, which will allow you to fill the blade as much as possible before carrying the material.
Minimise blade spillage
You can improve operating efficiency by minimising spillage from the blade while dozing. One method to achieve this is slot dozing.
This method is particularly useful at sites where material is prone to spill from the side of the blade due to large loads of relatively soft earth or movement down the hill, and at sites where the load must be carried a long way.
» The digging procedure should be in the order 1-3 shown in Figure 4.
» The depth of the trench should not exceed the height of the blade.
» The space between trenches should be approximately half the width of the blade.
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| FIGURE 2A. |
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| FIGURE 3A. |
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| FIGURE 3B. |
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| FIGURE 3C. |
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| FIGURE 4. |