The transportation
sector consumes around 70% of all petroleum in the US. In recent years, there
have been improvements in the efficiency of the vehicles, and hybrid techniques
that have been used to improve efficiency for conventional combustion vehicles.
Hydraulic systems have been used as an alternative to conventional electric
regenerative systems with good results. It has been proven that hydraulic
systems can improve energy consumption in conventional combustion vehicles and
in refuse collection vehicles. The control strategy has a large impact on the
performance of the system and studies have shown the control strategy selection
should be optimized and selected based on application. The performance of a
hydraulic accumulator was compared with the performance of a set of
ultracapacitors with the same energy storage capacity. The energy efficiency
for the ultracapacitor was around 79% and the energy efficiency of the
hydraulic accumulator was 87.7%. The power/mass ratio in the set of
ultracapacitors was 2.21 kW/kg and 2.69 kW/kg in the hydraulic accumulator. The
cost/power ratio is 217 US$/kW in the ultracapacitors and 75 US$/kW in the
hydraulic accumulator. Based on these results, the hydraulic accumulator was
selected as the energy storage device for the system. A testbench was designed,
modeled, implemented to test the energy storage system in different conditions
of operation. The experimental results of the testbench show how system can be
actively controlled for different operating conditions. The operating
conditions in the system can be adjusted by changing the number of rheostats
connected to the electric generator. Different variables in the system were
measured such as the angular shaft speed in the hydraulic pump, the torque and
speed in the hydraulic motor, the pressure in the system, the flow rate, and
the current and voltage in the electric generator. The control algorithm was
successfully implemented, the results for the pressure in the system and the
angular speed in the electric generator show how the control system can follow
a desired reference value. Two different controllers were implemented: one
controller for the pressure in the system, and one controller for the speed.
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12747050 |
| Date | 31 July 2020 |
| Creators | Jorge Leon Quiroga (9192758) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/DIGITAL_HYDRAULICS_IN_ELECTRIC_HYBRID_VEHICLES_TO_IMPROVE_EFFICIENCY_AND_BATTERY_USE/12747050 |
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