511
has been negligible till now, but recently such technological innovations have been installed in
some construction and mining machines (eg. OptiShift transmission from VOLVO). For this
purpose, a research method based on data from the onboard monitoring system installed on
the machine is proposed. The software of the on board monitoring system has been modified
as additional variables have been introduced to signal lockup activation.
3.2 Experimental data processing
The machine operation in underground mine is a very complex process that depends on many
factors [8]. To compare two machines and conclude on their efficiency one has to carefully
plan the experiment and recognise what parameters have the influence on final results. To
make such comparison reasonable, careful data selection has been done first [9]. The procedure consists of three main steps:
1. Selection of data samples to ensure comparability of machine working conditions. Based
on the data from the operators’ work records in the IT environment HR-TM (module of
the SAP system), we choose similar daily services. We rely on the following criteria:
• Mining unit ordering work,
• Place of work for a given machine,
• Type of work performed by a given machine,
• Length of the distance between mining face and mining screen.
2. Calculation of basic operational indicators for each shift based on monitoring data:
• Engine run time, using ENGRPM signal we count samples recorded in every 1 second
and the result is divided by 3600 [1h]. It is estimated for: total time, neutral gear, driving
of loaded machine—all in [hours],
• Fuel consumption, variable FUELUS is used, we sum up the samples of the signal
recorded in every 1 second, the result is divided by the 3600 [1h], so finally we obtain:
total consumption [dm
3
] and consumption for driving [dm
3 ],
• The distance traveled by the machine, variable SPEED is used, we sum up the samples
recorded in every 1 second, the result is divided by the 3600 [1h], so finally we obtain the
total distance [km],
• Oil temperature for the driving system: average oil temperature in [°C].
3. Calculation of indirect, operational key performance (efficiency) indicators for each work shift:
• Total fuel consumption per distance traveled [dm
3
/km],
• Fuel consumption for driving mode (a more reliable indicator) [dm
3 /km].
3.3 Discussion
The machines WO20TB with the lockup function have been used for over two years so far.
The solution has been proved to be failure-free and the cost of its installation (considering
cost of the whole machine) seems to be low, however, surprisingly the end-users have not
ordered machines with the lockup function. In our opinion, there was no measurable evidence to support the economic justification for introducing this modification. Thanks to the
use of the described method, measurable effects related to the reduction of fuel consumption have been confirmed. Moreover, we also showed positive impact on usage of brake
(lower temperature of oil suggests that operator used engine-based brake rather than conventional friction-based braking system to slow down that will increase life time of a brake).
4 RESULTS
In this section, step by step, the results of the proposed procedure will be presented and discussed. First, in Fig. 6 we show that the efficiency of the transmission is better when using
the lockup function, because the average fuel consumption (FUELUS) is smaller and even
has been negligible till now, but recently such technological innovations have been installed in
some construction and mining machines (eg. OptiShift transmission from VOLVO). For this
purpose, a research method based on data from the onboard monitoring system installed on
the machine is proposed. The software of the on board monitoring system has been modified
as additional variables have been introduced to signal lockup activation.
3.2 Experimental data processing
The machine operation in underground mine is a very complex process that depends on many
factors [8]. To compare two machines and conclude on their efficiency one has to carefully
plan the experiment and recognise what parameters have the influence on final results. To
make such comparison reasonable, careful data selection has been done first [9]. The procedure consists of three main steps:
1. Selection of data samples to ensure comparability of machine working conditions. Based
on the data from the operators’ work records in the IT environment HR-TM (module of
the SAP system), we choose similar daily services. We rely on the following criteria:
• Mining unit ordering work,
• Place of work for a given machine,
• Type of work performed by a given machine,
• Length of the distance between mining face and mining screen.
2. Calculation of basic operational indicators for each shift based on monitoring data:
• Engine run time, using ENGRPM signal we count samples recorded in every 1 second
and the result is divided by 3600 [1h]. It is estimated for: total time, neutral gear, driving
of loaded machine—all in [hours],
• Fuel consumption, variable FUELUS is used, we sum up the samples of the signal
recorded in every 1 second, the result is divided by the 3600 [1h], so finally we obtain:
total consumption [dm
3
] and consumption for driving [dm
3 ],
• The distance traveled by the machine, variable SPEED is used, we sum up the samples
recorded in every 1 second, the result is divided by the 3600 [1h], so finally we obtain the
total distance [km],
• Oil temperature for the driving system: average oil temperature in [°C].
3. Calculation of indirect, operational key performance (efficiency) indicators for each work shift:
• Total fuel consumption per distance traveled [dm
3
/km],
• Fuel consumption for driving mode (a more reliable indicator) [dm
3 /km].
3.3 Discussion
The machines WO20TB with the lockup function have been used for over two years so far.
The solution has been proved to be failure-free and the cost of its installation (considering
cost of the whole machine) seems to be low, however, surprisingly the end-users have not
ordered machines with the lockup function. In our opinion, there was no measurable evidence to support the economic justification for introducing this modification. Thanks to the
use of the described method, measurable effects related to the reduction of fuel consumption have been confirmed. Moreover, we also showed positive impact on usage of brake
(lower temperature of oil suggests that operator used engine-based brake rather than conventional friction-based braking system to slow down that will increase life time of a brake).
4 RESULTS
In this section, step by step, the results of the proposed procedure will be presented and discussed. First, in Fig. 6 we show that the efficiency of the transmission is better when using
the lockup function, because the average fuel consumption (FUELUS) is smaller and even