Power efficiency control mechanism for a working machine

Patent metadata

Field	Value
Publication number	US-10160439-B2
Application number	US-201515319959-A
Country	US
Kind code	B2
Filing date	Jun 18, 2015
Priority date	Jun 20, 2014
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

A control system for a working machine that includes a power consumer (14) includes a prime mover (12), an energy storage unit (24) for storing energy, an auxiliary power unit (20) for generating power or consuming power, the auxiliary power unit (20) having a first connection (20a) coupled to the prime mover (12) and a second connection couplable to the energy storage unit (24). A controller (18) operatively coupled to the prime mover (12) and operatively couplable to the power consumer (14) is configured to estimate a required power of the power consumer (14), and to command the prime mover (14) to operate at an optimal operating point that produces the estimated required power. Based on a relationship between power output capability of the prime mover and power consumption of the power consumer, the controller (18) is configured to at least one of command that excess power capacity from the prime mover be provided to the auxiliary power unit for storage in the energy storage unit, or command that energy stored in the energy storage unit be provided to the auxiliary power unit to drive the power consumer.

First claim

What is claimed is:

1. A control system for a working machine that includes a power consumer, comprising:
a prime mover;
an energy storage unit configured to store energy;
an auxiliary power unit configured to store power or consume power, the auxiliary power unit having a first connection coupled to the prime mover and a second connection couplable to the energy storage unit; and
a controller operatively coupled to the prime mover and operatively couplable to the power consumer, the controller configured to:
estimate, based on data from at least one sensor, a required power of the power consumer,
compare the estimated required power to speed and torque output of the prime mover along constant power lines of the prime mover;
determine, based on the comparison, which constant power line can produce the estimated required power at a most energy-efficient operating point for the prime mover;
command the prime mover to operate along the constant power line that can produce the estimated required power at the most energy-efficient operating point, and
based on a relationship between power output capability of the prime mover and power consumption of the power consumer, the controller is configured to at least one of
i) command that excess power capacity from the prime mover be provided to the auxiliary power unit for storage in the energy storage unit, or
ii) command that energy stored in the energy storage unit be provided to the auxiliary power unit to drive the power consumer.

2. The system according to claim 1 , further comprising a first clutch having a first clutch input and a first clutch output, the first clutch operable to selectively couple and decouple the first clutch input from the first clutch output, wherein the first clutch input is coupled to the prime mover and the first clutch output is coupled to the power consumer,
and the controller is operatively coupled to the first clutch and configured to command the first clutch to decouple the prime mover from the power consumer when the estimated required power is less than a first prescribed value and energy stored in the energy storage unit is greater than a second prescribed value.

3. The system according to claim 1 , wherein the controller is further configured to disable the prime mover when the estimated required power is less than a first prescribed value and energy stored in the energy storage unit is greater than a second prescribed threshold.

4. The system according to claim 3 , wherein the controller is further configured to command the auxiliary power unit to operate in a motoring mode when the prime mover is in the disabled state and the energy stored in the energy storage unit is greater than the second prescribed value.

5. The system according to claim 1 , further comprising a second clutch having a second clutch input and a second clutch output, the second clutch operable to selectively couple and decouple the second clutch input from the second clutch output, wherein the second clutch input is coupled to the auxiliary power unit and the second clutch output is coupled to the power consumer,
and the controller is operatively coupled to the second clutch and configured to command the second clutch to decouple the auxiliary power unit from the power consumer when a difference between the power output by the prime mover and the power consumed by the power consumer is non-negative and less than a third prescribed value.

6. The system according to claim 1 , wherein estimating the required power of the power consumer includes measuring a load placed on the power consumer, and estimating the required power based on the measured load.

7. The system according to claim 1 , further comprising the power consumer, wherein the power consumer is coupled to the prime mover and the auxiliary power unit.

8. The system according to claim 1 , wherein the prime mover comprises one of an internal combustion engine, a hydraulic motor, or an electric motor.

9. The system according to claim 1 , wherein the auxiliary power unit comprises a hydraulic pump operable in a first mode for generating hydraulic power and a second mode for consuming hydraulic power.

10. The system according to claim 1 , wherein the auxiliary power unit comprises at least one of a hydraulic machine or an electric machine.

11. The system according to claim 1 , wherein the energy storage unit comprises at least one of an accumulator for storing hydraulic energy or a battery for storing electric energy.

12. The system according to claim 1 , wherein the working machine comprises an excavator.

13. The system according to claim 1 , wherein the controller is configured to determine an optimal operating condition by finding a lowest prime mover speed and a highest prime mover torque that produces the estimated required power for the power consumer.

14. The system according to claim 1 , wherein the controller is configured to store a motion profile, and automatically execute the stored motion profile.

15. The system according to claim 1 , wherein the controller is configured to compare system operating parameters to baseline parameters, and upon the system operating parameters deviating from the baseline parameters by a prescribed threshold, conclude component provide an indication of possible component failure.

16. The system according to claim 15 , wherein the system parameters comprise at least one of prime mover power output, prime mover speed, power consumer power input, hydraulic unit power, and hydraulic unit pressure.

17. A controller for a working machine that includes a power consumer, a prime mover, an energy storage unit configured to store power, and an auxiliary power unit configured to generate or consume power, the controller comprising:
a processor and memory;
logic stored in memory and executable by the processor, the logic including
logic configured to estimate, based on data from at least one sensor, a required power of the power consumer,
logic configured to compare the estimated required power to speed and torque output of the prime mover along constant power lines of the prime mover;
logic configured to determine, based on the comparison, which constant power line can produce the estimated required power at a most energy-efficient operating point for the prime mover;
logic configured to command the prime mover to operate along the constant power line that can produce the estimated required power at the most energy-efficient operating point, and
logic configured to at least one of
i) command that excess power producible by the prime mover be provided to the auxiliary power unit for storage in the energy storage unit, or
ii) command that energy stored in the energy storage unit be provided to the auxiliary power unit to drive the power consumer,

wherein the command to provide excess power to the auxiliary power unit or provide energy stored in the energy storage unit to the auxiliary power unit is based on a relationship between power output capacity of the prime mover and power consumption of the power consumer.

18. The controller according to claim 17 , wherein the controller further includes logic configured to disable the prime mover when the estimated required power is less than a first prescribed value and energy stored in the energy storage unit is greater than a second prescribed threshold.

19. The controller according to claim 17 , wherein the controller further includes logic configured to command the auxiliary power unit to operate in a motoring mode when the prime move

Assignees

• Parker Hannifin Corp

Inventors

• Zhang Hao
• Collett Raymond
• Jiang Zhesheng
• Carl Blake

Classifications

• B60W10/26

  for electrical energy, e.g. batteries or capacitors · CPC title

• Y10S903/93

  Conjoint control of different elements · CPC title

• B60W20/11 Primary

  using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance {(utilising navigation and traffic information in the control strategy B60W20/12)} · CPC title

• Y10S903/946

  Characterized by control of driveline clutch · CPC title

• B60W2300/17

  Construction vehicles, e.g. graders, excavators · CPC title