Machine having hydraulic start assist system

{
  "publication_number": "US9745940B2",
  "country": "US",
  "kind": "B2",
  "title": "Machine having hydraulic start assist system",
  "abstract": "A hydraulic system is disclosed for assisting starting of a machine having an engine. The hydraulic system may include a work tool, a pump driven by the engine to pressurize fluid, and an actuator configured to receive pressurized fluid from the pump and move the work tool. The hydraulic system may also include an accumulator configured to selectively receive pressurized fluid from the pump and from the actuator, an electric starter configured to start the engine, and a motor selectively supplied with fluid from the accumulator to assist the electric starter in starting the engine.",
  "claims": [
    "1. A hydraulic start assist system for a machine having an engine, comprising: a work tool; a pump driven by the engine to pressurized fluid; an actuator configured to receive pressurized fluid from the pump and move the work tool; an accumulator connected to receive pressurized fluid from the pump and from the actuator; an electric starter configured to start the engine; and a motor selectively supplied with fluid from the accumulator to assist the electric starter in starting the engine, when the accumulator has a capacity to drive the motor; and a controller wherein the controller is further configured to selectively shut down the engine based on a status of the accumulator.",
    "2. The hydraulic start assist system of claim 1, further including a boom connected between the machine and the work tool, wherein the actuator is a swing motor configured to swing the boom.",
    "3. The hydraulic start assist system of claim 2, wherein: the actuator is a first actuator; the accumulator is a first accumulator associated with the first actuator; the hydraulic start assist system further includes: a boom cylinder configured to raise and lower the boom; and a second accumulator configured to receive pressurized fluid from the pump and from the boom cylinder; and the motor is selectively supplied with fluid from the second accumulator to assist the electric starter in starting the engine.",
    "4. The hydraulic start assist system of claim 1, wherein the motor is configured to selectively start the engine without assistance from the electric starter.",
    "5. The hydraulic start assist system of claim 4, wherein the electric starter is configured to selectively start the engine without assistance from the motor.",
    "6. The hydraulic start assist system of claim 5, further including a controller in communication with the electric starter, the controller being configured to cause the electric starter to start the engine alone, the motor to start the engine alone, or the electric starter and the motor to start the engine together based on the capacity of the accumulator.",
    "7. The hydraulic start assist system of claim 6, wherein the capacity is at least one of a pressure and an amount of fluid stored within the accumulator.",
    "8. The hydraulic start assist system of claim 6, wherein the controller is configured to shut down the engine only when the accumulator has sufficient capacity to restart the engine with the motor alone.",
    "9. The hydraulic start assist system of claim 8, wherein the controller is further configured to cause the accumulator to charge with fluid when it is determined that the accumulator does not have capacity to restart the engine and the engine should be shut down.",
    "10. The hydraulic start assist system of claim 8, wherein the controller is configured to selectively shut down the engine based further on a status and a presence of an operator within the machine.",
    "11. The hydraulic start assist system of claim 10, wherein the controller is configured to selectively shut down the engine when the operator is present in the machine and has been inactive for at least a threshold period of time.",
    "12. The hydraulic start assist system of claim 11, wherein the controller is configured to cause restart of the engine when the operator becomes active after shutdown of the engine.",
    "13. The hydraulic start assist system of claim 12, wherein the controller is configured to cause restart of the engine when a parameter of the machine deviates from a threshold value.",
    "14. The hydraulic start assist system of claim 13, wherein the parameter includes at least one of a battery voltage and a temperature of the engine.",
    "15. The hydraulic start assist system of claim 13, wherein the controller is further configured to: track a number of times that the engine is shut down, and selectively inhibit restart of the engine when the number of times that the engine has been shut down exceeds a threshold number.",
    "16. A method of operating a machine having an engine, comprising: determining inactivity of a machine operator; determining an ability to hydraulically restart the engine; and selectively shutting down the engine when the machine operator is inactive and the ability to hydraulically restart the engine exists.",
    "17. The method of claim 16, further including hydraulically restarting the engine with assistance from an electric starter.",
    "18. The method of claim 16, wherein hydraulically restarting the engine includes hydraulically restarting the engine when the machine operator becomes active after engine shutdown.",
    "19. A machine, comprising: a frame; an engine mounted to the frame; a boom; a swing motor configured to swing the boom relative to the frame; a boom cylinder configured to raise and lower the boom relative to the frame; a pump driven by the engine to supply pressurized fluid to the swing motor and to the boom cylinder; a first accumulator configured to receive pressurized fluid from the pump and from the swing motor; a second accumulator configured to receive pressurized fluid from the pump and from the boom cylinder; an electric starter configured to start the engine; a hydraulic motor configured to start the engine; and a controller configured to: determine an activity level of a machine operator; determine a status of the first and second accumulators; selectively shutdown the engine when the machine operator is inactive and the first and second accumulators have a capacity to drive the hydraulic motor to start the engine alone; selectively restart the engine using the electric starter alone, the hydraulic motor alone, or the electric starter and the hydraulic motor together when the machine operator becomes active after engine shutdown and based on the capacity of the first and second accumulators."
  ],
  "description_excerpt": "The present disclosure relates generally to a machine and, more particularly, to a machine having hydraulic start assist system.\n\nHydraulic machines such as excavators, dozers, loaders, backhoes, motor graders, and other types of heavy equipment use one or more hydraulic actuators to accomplish a variety of tasks. These actuators are fluidly connected to an engine-driven pump of the machine that provides pressurized fluid to chambers within the actuators. As the pressurized fluid moves into or through the chambers, the pressure of the fluid acts on hydraulic surfaces of the chambers to affect movement of the actuators and a connected work tool.\n\nOne problem associated with this type of hydraulic arrangement involves efficiency. In particular, there may be times when the hydraulic machine is idle and yet still operational. For example, during a truck loading cycle, when an excavator finishes loading a first truck, the excavator must wait for the first truck to depart and a second truck to arrive before additional loading tasks can be completed. And during this time, the engine of the machine may still be turned on (often at high speeds) and needlessly consuming fuel. In these situations, it may be beneficial to selectively turn the engine off to consume fuel.\n\nHowever, restarting the engine can be harsh on the machine's electrical circuit and cause delays in the work cycle of the machine. Specifically, the electrical circuit could be called on to restart the engine hundreds of times during a particular work shift. In some applications, this overuse of the electrical circuit could cause premature wear and/or failure.",
  "cpc": [
    "F02N 7/08",
    "B60K 2006/126",
    "B60K 6/12",
    "B60W 2300/17",
    "E02F 9/2066",
    "E02F 9/2217",
    "E02F 9/2246",
    "E02F 9/2289",
    "E02F 9/2292",
    "E02F 9/2296",
    "F02N 11/00",
    "F02N 2300/2002",
    "F15B 2211/212",
    "F15B 2211/851",
    "Y02T 10/62"
  ],
  "ipc": [
    "E02F 9/14",
    "E02F 9/24",
    "F15B 1/04",
    "F15B 11/04",
    "F15B 15/08",
    "F15B 21/14",
    "E02F 9/20",
    "E02F 9/22",
    "F02N 11/00",
    "F02N 7/08",
    "F16D 31/02"
  ],
  "assignees": [
    "Caterpillar Inc"
  ],
  "inventors": [
    "Emily Anne MORRIS",
    "Jeremy Todd Peterson",
    "Jeffrey Lee Kuehn",
    "Dayao Chen",
    "Pengfei Ma"
  ],
  "filing_date": "2014-09-10",
  "publication_date": "2017-08-29",
  "grant_date": "2017-08-29",
  "priority_date": "2014-02-28",
  "application_number": "US-201414482557-A",
  "family_id": "54006575",
  "cited_by_count": 5,
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}