US 9133837

US patent 9133837 has the following details:

• Title: Method of controlling a hydraulic system
• Assignee: Caterpillar Inc.
• Inventors: Mark David Anderson, Michael Anthony Spielman, JR.
• Filing Date: 2008-04-24
• Issue Date: 2015-09-15
• Abstract: A method of controlling a hydraulic system having a variable displacement pump operatively coupled to an engine. The method includes detecting a speed of the engine, and determining a desired power value of the pump. The method also includes identifying an allowable power value that may be expended by the pump at the detected speed. The method also includes selecting a pump power value. The selected pump power value is the lower of the allowable power value and the desired power value. The method further includes adjusting the pump to deliver the selected pump power value.

Here is a plain-language overview of each independent claim:

• Claim 1 (Method of controlling a hydraulic system): This claim describes a method for managing a hydraulic system where an engine drives a pump that can change its output. The steps include:

  1. Measuring the engine's speed.
  2. Figuring out the amount of power the user wants the pump to provide.
  3. Consulting a pre-defined table or "map" to find the maximum power the pump is allowed to use at the detected engine speed.
  4. Choosing the lesser of these two power values (what the user wants vs. what's allowable).
  5. Adjusting the pump to deliver that chosen, limited power.

• Claim 11 (Hydraulic system): This claim describes the components of a hydraulic system designed to control power delivery. It includes:

  1. An engine.
  2. A variable displacement pump, where the hydraulic power it delivers depends on how much its internal pistons move.
  3. A tool or attachment (implement) connected to the pump that uses its power.
  4. A sensor to measure the engine's speed.
  5. A control system that performs several functions:
     • It looks up an allowable power output for the pump based on a map that links this value to the engine's speed.
     • It determines the desired power output requested by the user for the implement.
     • It then adjusts the pump's piston movement to ensure the power delivered to the implement is the lower of the allowable power and the desired power.

• Claim 15 (Method of operating a machine): This claim outlines a method for operating a machine that has an engine and a hydraulic implement powered by a pump. The method involves:

  1. Detecting a signal from the user (e.g., from a lever) that indicates how much power they want for the implement.
  2. Monitoring the engine's speed.
  3. Selecting an allowable power level for the implement from a map that correlates allowable power with the current engine speed.
  4. Adjusting the pump to deliver to the implement the lower of the desired power level and the allowable power level.

USPTO and CAFC 2026 Docket Search:
A search of the USPTO database indicates that US patent 9133837 is currently Active and is set to expire on 2034-03-13.
As of April 26, 2026, there are no results found in CAFC 2026 dockets specifically for patent number 9133837.US patent 9133837 has the following details:

• Title: Method of controlling a hydraulic system
• Assignee: Caterpillar Inc.
• Inventors: Mark David Anderson, Michael Anthony Spielman, JR.
• Filing Date: 2008-04-24
• Issue Date: 2015-09-15
• Abstract: A method of controlling a hydraulic system having a variable displacement pump operatively coupled to an engine. The method includes detecting a speed of the engine, and determining a desired power value of the pump. The method also includes identifying an allowable power value that may be expended by the pump at the detected speed. The method also includes selecting a pump power value. The selected pump power value is the lower of the allowable power value and the desired power value. The method further includes adjusting the pump to deliver the selected pump power value.

Here is a plain-language overview of each independent claim:

• Claim 1 (Method of controlling a hydraulic system): This claim describes a method for managing a hydraulic system where an engine drives a pump that can change its output. The steps include:

  1. Measuring the engine's speed.
  2. Figuring out the amount of power the user wants the pump to provide.
  3. Consulting a pre-defined table or "map" to find the maximum power the pump is allowed to use at the detected engine speed.
  4. Choosing the lesser of these two power values (what the user wants vs. what's allowable).
  5. Adjusting the pump to deliver that chosen, limited power.

• Claim 11 (Hydraulic system): This claim describes the components of a hydraulic system designed to control power delivery. It includes:

  1. An engine.
  2. A variable displacement pump, where the hydraulic power it delivers depends on how much its internal pistons move.
  3. A tool or attachment (implement) connected to the pump that uses its power.
  4. A sensor to measure the engine's speed.
  5. A control system that performs several functions:
     • It looks up an allowable power output for the pump based on a map that links this value to the engine's speed.
     • It determines the desired power output requested by the user for the implement.
     • It then adjusts the pump's piston movement to ensure the power delivered to the implement is the lower of the allowable power and the desired power.

• Claim 15 (Method of operating a machine): This claim outlines a method for operating a machine that has an engine and a hydraulic implement powered by a pump. The method involves:

  1. Detecting a signal from the user (e.g., from a lever) that indicates how much power they want for the implement.
  2. Monitoring the engine's speed.
  3. Selecting an allowable power level for the implement from a map that correlates allowable power with the current engine speed.
  4. Adjusting the pump to deliver to the implement the lower of the desired power level and the allowable power level.

USPTO and CAFC 2026 Docket Search:
A search of the USPTO database indicates that US patent 9133837 is currently Active and is set to expire on 2034-03-13.
As of April 26, 2026, there are no results found in CAFC 2026 dockets specifically for patent number 9133837.

As of April 26, 2026, there is no known litigation involving US patent 9133837. A search of patent litigation databases did not yield any results for this specific patent number.

Proceedings overview

There are no AIA trial proceedings (Inter Partes Review, Post-Grant Review, or Covered Business Method) on file for US patent 9133837. This means the patent has not been challenged in an AIA trial before the Patent Trial and Appeal Board (PTAB). This gives a defendant a strong defensive posture in terms of PTAB history, as all claims remain untested by this specific challenge mechanism.

Strategic summary

As of May 27, 2026, all claims of US patent 9133837 (claims 1-20) are UNTESTED by any AIA trial proceeding at the PTAB. There are no claims that have been canceled or sustained through IPR, PGR, or CBM trials.

Since no AIA trial proceedings have been initiated against US patent 9133837, the estoppel provisions of § 315(e)(2) are not applicable. This means that any potential petitioner (or their privies) is not barred from raising any prior-art grounds they could have raised in a past IPR. All prior-art grounds remain available for a future challenge.

There are no pattern signals to discern, such as multiple IPRs filed by the same petitioner, aggressive PTAB appeals by the patent owner, or involvement of defensive aggregators, due to the complete absence of PTAB activity.

Recommended next steps

If a defendant is currently facing assertion of US patent 9133837, the absence of PTAB activity indicates that an IPR petition remains a viable and unexercised defense strategy. It would be advisable to:

• Conduct a thorough prior art search to identify potential grounds for invalidity under 35 U.S.C. §§ 102 and 103, which could form the basis of an IPR petition.
• Evaluate the strength of these potential grounds against the claims of US patent 9133837 to determine the likelihood of institution and ultimately, invalidation.
• Consider the strategic advantages of initiating an IPR, such as the lower burden of proof (preponderance of the evidence) compared to district court litigation, and the potential for a quicker resolution.

Inventors

• Mark David Anderson (Employer: Caterpillar Inc.)
• Michael Anthony Spielman, JR. (Employer: Caterpillar Inc.)

Both inventors were employed by Caterpillar Inc. at the time of filing, as indicated by the immediate assignment of their interest to Caterpillar Inc. on the filing date.

Original assignee

The original assignee named on the issued patent is Caterpillar Inc.

Caterpillar Inc. is the world's leading manufacturer of construction and mining equipment, off-highway diesel and natural gas engines, industrial gas turbines, and diesel-electric locomotives. Their primary line of business involves designing, manufacturing, marketing, and selling machinery and engines, along with providing financial services. The patent describes a method for controlling hydraulic systems in construction machines with hydraulically controlled implements, a direct application for Caterpillar's product lines, such as excavators. Caterpillar Inc. is currently an active, operating, publicly traded company (NYSE: CAT).

Assignment timeline

• 2008-03-31 to 2008-04-10 (executed) / recorded 2008-04-24 — Reel 020910/0263
  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: SPIELMAN, JR., MICHAEL ANTHONY; ANDERSON, MARK DAVID
  • Assignee: CATERPILLAR INC., ILLINOIS
  • Correspondent: Not specified in provided data.
  • Context: Initial assignment from inventors to the corporate assignee at the time of patent application filing.

The USPTO Assignment Center currently shows only this initial assignment from the inventors to Caterpillar Inc. as recorded for US Patent 9133837.

Timeline diagram

timeline
    title Ownership of US 9133837
    2008 : Filed and assigned to Caterpillar Inc.
    2015 : Issued to Caterpillar Inc.

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The only recorded assignment is from the inventors to Caterpillar Inc., an operating company that manufactures products related to the patent.
2. Known asserter in the chain — Not present. Caterpillar Inc. is not identified as a known patent asserter (NPE) in public lists.
3. Repeat correspondent across the chain — Not present. There is only one assignment event recorded, and the correspondent information for that event is not specified in the provided data.
4. Cascading transfers — Not present. There is only one recorded assignment.
5. Pre-litigation transfer — Not present. There is no recorded litigation, and only one initial assignment.
6. Bankruptcy fire-sale — Not present. Caterpillar Inc. is an active, operating company and there is no indication of bankruptcy or patent sales in such proceedings.
7. Privateering — Not present. There is no evidence of a transfer to an NPE for assertion on behalf of an operating company.
8. Defensive aggregator (anti-NPE) — Not present. The patent is currently assigned to Caterpillar Inc., an operating company, not a defensive aggregator.

Verdict

Operating-company assertion (current assignee ships products embodying the claims and is suing actual competitors).
This verdict is based on the sole recorded assignment (Reel 020910/0263, recorded 2008-04-24), which shows the patent was initially assigned from the inventors to Caterpillar Inc., a prominent operating company in the heavy machinery sector. There are no subsequent assignments to any shell entities or known NPEs, nor is there any indication of litigation or other NPE-related activities. The patent's subject matter directly relates to Caterpillar Inc.'s core business of manufacturing construction and mining equipment that utilizes hydraulic systems.

USPTO Assignment Center search: https://assignmentcenter.uspto.gov/

The USPTO database confirms that US patent 9133837, titled "Method of controlling a hydraulic system," is currently Active and is projected to expire on March 13, 2034.

Here is an analysis of the most relevant prior art cited in US patent 9133837, focusing on potential anticipation under 35 U.S.C. § 102:

Prior Art Citations and Potential Anticipation:

The patent text explicitly mentions U.S. Pat. No. 5,525,043 ('043 patent) as relevant background art.

• U.S. Pat. No. 5,525,043 (Lukich):
  • Full Citation: US5525043A.
  • Publication Date: 1996-06-11 (Filing Date: 1993-12-23).
  • Brief Description: This patent describes a hydraulic control system designed to reduce engine lug. It uses multiple sensors to detect various operating parameters of the hydraulic system (including the pump and engine) to calculate a parameter signal indicating engine load. When the engine load exceeds a predefined level, the displacement of the variable displacement pump is reduced, allowing the engine speed to increase to a predefined level.
  • Potential Anticipation of Claims: The '043 patent broadly addresses controlling hydraulic systems to prevent engine lug by adjusting pump displacement based on engine load. This could potentially anticipate aspects of Claim 1, Claim 11, and Claim 15, particularly the concept of sensing engine speed and adjusting pump output to prevent engine lug. However, US9133837B2 distinguishes itself by focusing on a simpler methodology that directly compares desired power to an allowable power determined from a map, aiming for reduced complexity and cost compared to the '043 patent's "number of operating parameters" and "minimum amount of oscillation" approach.

Beyond the specifically discussed '043 patent, US9133837B2 also lists several other prior art documents. A selection of these are analyzed below for their relevance to the independent claims (Claim 1, Claim 11, and Claim 15):

• US3877839A (Ifield):

  • Full Citation: US3877839A.
  • Publication Date: 1975-04-15 (Filing Date: 1972-10-23).
  • Brief Description: This patent describes "Torque limiting means for variable displacement pumps".
  • Potential Anticipation of Claims: This patent could potentially anticipate aspects of Claim 1, Claim 11, and Claim 15, specifically the concept of limiting the power or torque of a variable displacement pump. The core idea of setting a maximum allowable output for the pump based on operational parameters, even if those parameters differ, aligns with the fundamental control objective.

• US4395199A (Hitachi Construction Machinery Co., Ltd.):

  • Full Citation: US4395199A.
  • Publication Date: 1983-07-26 (Filing Date: 1979-10-15).
  • Brief Description: This patent details a "Control method of a system of internal combustion engine and hydraulic pump".
  • Potential Anticipation of Claims: Given its title, this patent likely covers methods for controlling hydraulic pumps driven by internal combustion engines, which is central to all independent claims of US9133837B2. It could potentially anticipate aspects of detecting engine speed, determining desired power, identifying allowable power, and adjusting the pump, depending on the specific control logic disclosed.

• US4534707A (Caterpillar Tractor Co.):

  • Full Citation: US4534707A.
  • Publication Date: 1985-08-13 (Filing Date: 1984-05-14).
  • Brief Description: This patent is for a "Hydrostatic vehicle control".
  • Potential Anticipation of Claims: While broader, a hydrostatic vehicle control system inherently manages engine power distribution to hydraulic components. It might anticipate elements of engine speed detection and power allocation in a hydraulic system, thus potentially impacting claims 1, 11, and 15, especially if it describes methods of limiting hydraulic power to prevent engine overload.

• US4606313A (Hitachi Construction Machinery Co., Ltd.):

  • Full Citation: US4606313A.
  • Publication Date: 1986-08-19 (Filing Date: 1980-10-09).
  • Brief Description: This patent describes a "Method of and system for controlling hydraulic power system".
  • Potential Anticipation of Claims: Similar to US4395199A, this patent directly relates to controlling hydraulic power systems, a core element of all independent claims. The specific control methodology would need to be examined to determine the extent of anticipation, particularly regarding the use of maps for allowable power values and the comparison with desired power.

• US5050379A (Kabushiki Kaisha Toyoda Jidoshokki Seisakusho):

  • Full Citation: US5050379A.
  • Publication Date: 1991-09-24 (Filing Date: 1990-08-23).
  • Brief Description: This patent describes "Displacement of a variable displacement hydraulic pump and speed of an engine driving the pump controlled based on demand".
  • Potential Anticipation of Claims: This patent's description strongly aligns with the core concepts of US9133837B2, specifically the control of a variable displacement pump and engine speed based on demand. It could potentially anticipate all independent claims, particularly the steps of determining a desired power value (based on demand), detecting engine speed, and adjusting pump displacement. The novelty of US9133837B2 might reside in the explicit use of an "allowable power value" derived from a "map" and the specific comparison logic.

• US5214916A (Caterpillar Inc.):

  • Full Citation: US5214916A.
  • Publication Date: 1993-06-01 (Filing Date: 1992-01-13).
  • Brief Description: This patent is titled "Control system for a hydraulic work vehicle".
  • Potential Anticipation of Claims: As it describes a control system for a hydraulic work vehicle, it likely involves managing engine and hydraulic pump interactions. This could potentially anticipate elements of Claim 1 and Claim 11, particularly regarding the system architecture and the general idea of controlling a hydraulic pump coupled to an engine.

• US5295353A (Kabushiki Kaisha Komatsu Seisakusho):

  • Full Citation: US5295353A.
  • Publication Date: 1994-03-22 (Filing Date: 1990-06-06).
  • Brief Description: This patent describes a "Controlling arrangement for travelling work vehicle".
  • Potential Anticipation of Claims: This patent could potentially anticipate aspects of Claim 1, Claim 11, and Claim 15 by describing a control arrangement for a work vehicle that likely includes hydraulic systems and engine management, especially concerning how power is supplied to implements or traction.

• US5477679A (Hitachi Construction Machinery Co., Ltd.):

  • Full Citation: US5477679A.
  • Publication Date: 1995-12-26 (Filing Date: 1990-10-16).
  • Brief Description: This patent describes an "Apparatus for controlling revolution speed of prime mover for hydraulically propelled work vehicle".
  • Potential Anticipation of Claims: This patent's focus on controlling the revolution speed of a prime mover (engine) for a hydraulically propelled vehicle directly relates to the engine speed detection and control aspects of US9133837B2. It could potentially anticipate Claim 1 and Claim 15, particularly the steps involving sensing engine speed and adjusting hydraulic output to maintain engine performance.

• US5576962A (Caterpillar Inc.):

  • Full Citation: US5576962A.
  • Publication Date: 1996-11-19 (Filing Date: 1995-03-16).
  • Brief Description: This patent is titled "Control system and method for a hydrostatic drive system".
  • Potential Anticipation of Claims: This patent, from the same assignee, concerns controlling hydrostatic drive systems, which are a type of hydraulic system. It could potentially anticipate aspects of all independent claims related to system control, method of control, and system components, especially if it describes managing power between an engine and a hydraulic pump to optimize performance or prevent lugging.

• US5934879A (Hitachi Construction Machinery Co., Ltd.):

  • Full Citation: US5934879A.
  • Publication Date: 1999-08-10 (Filing Date: 1995-12-22).
  • Brief Description: This patent is for a "Pump torque control system".
  • Potential Anticipation of Claims: This patent directly addresses pump torque control, which is a form of power control for a pump. It could potentially anticipate claims 1, 11, and 15, particularly the concept of controlling the power value of the pump. The specific method of control and how allowable torque is determined would be critical in assessing the extent of anticipation.

• US5951258A (Caterpillar Inc.):

  • Full Citation: US5951258A.
  • Publication Date: 1999-09-14 (Filing Date: 1997-07-09).
  • Brief Description: This patent is for a "Torque limiting control system for a hydraulic work machine".
  • Potential Anticipation of Claims: Another patent from Caterpillar Inc., this one specifically describes a "torque limiting control system" for a hydraulic work machine. This is highly relevant to US9133837B2's concept of an "allowable power value" (which can be torque) and adjusting the pump to deliver a selected power value. It could potentially anticipate all independent claims, particularly the mechanism of limiting power to avoid overloading the engine.

• US6010309A (Komatsu Ltd.):

  • Full Citation: US6010309A.
  • Publication Date: 2000-01-04 (Filing Date: 1997-01-31).
  • Brief Description: This patent describes a "Control device for variable capacity pump".
  • Potential Anticipation of Claims: The control of a variable capacity (displacement) pump is a fundamental aspect of US9133837B2. This patent could potentially anticipate elements of all independent claims related to adjusting the pump to deliver a specific power value or displacement, depending on the control logic used in the prior art.

• US6021756A (Hitachi Construction Machinery Co., Ltd.):

  • Full Citation: US6021756A.
  • Publication Date: 2000-02-08 (Filing Date: 1997-05-27).
  • Brief Description: This patent describes an "Engine control system for construction machine".
  • Potential Anticipation of Claims: This patent's focus on an engine control system for a construction machine, which typically employs hydraulic implements, could potentially anticipate aspects of Claim 1, Claim 11, and Claim 15. The specific methods of engine and hydraulic pump coordination would determine the degree of anticipation.

Obviousness Analysis under 35 U.S.C. § 103 for US Patent 9133837

This analysis considers combinations of prior art references that would render the claims of US Patent 9133837 obvious to a person having ordinary skill in the art (POSITA) at the time of the invention (priority date 2008-04-24). The patent itself discusses US Pat. No. 5,525,043, highlighting its complexity as a problem the current invention seeks to address. However, other prior art references cited by the examiner are also highly relevant.

Primary Reference: US 5,050,379 A to Kabushiki Kaisha Toyoda Jidoshokki Seisakusho (Toyoda)

US Patent 5,050,379 A, titled "Displacement of a variable displacemet hydraulic pump and speed of an engine driving the pump controlled based on demand," discloses a control method and system for a hydraulic work machine. This patent appears to teach all elements of the independent claims of US 9133837.

Obviousness of Independent Claim 1 (Method of controlling a hydraulic system)

Claim 1 of US 9133837 recites:
"A method of controlling a hydraulic system having a variable displacement pump operatively coupled to an engine, comprising:
detecting a speed of the engine;
determining a desired power value of the pump based on user input;
identifying an allowable power value that may be expended by the pump based on a map that indicates the allowable power value at the detected speed;
selecting a pump power value, the selected pump power value being the lower of the allowable power value and the desired power value; and
adjusting the pump to deliver the selected pump power value."

Toyoda discloses each of these elements:

• Detecting a speed of the engine: Toyoda teaches that "engine speed N is detected by engine speed sensor" (Col. 4, lines 52-53).
• Determining a desired power value of the pump based on user input: Toyoda senses "demand for the hydraulic pump" (Col. 4, line 49), which leads to the determination of a "target pump displacement Dd" (Col. 4, line 50), representing the desired power.
• Identifying an allowable power value that may be expended by the pump based on a map that indicates the allowable power value at the detected speed: Toyoda explicitly states that "permissible engine load Tp is determined based on the engine speed N by using a map" (Col. 4, lines 53-54). This "permissible engine load" functions as the allowable power value.
• Selecting a pump power value, the selected pump power value being the lower of the allowable power value and the desired power value: Toyoda teaches that "When the target pump displacement Dd causes the engine to be overloaded, a load control circuit... reduces the pump displacement from the target pump displacement Dd so that the engine load is restricted to the permissible engine load Tp." (Col. 4, lines 56-60). This directly corresponds to selecting the lower of the desired and allowable power values.
• Adjusting the pump to deliver the selected pump power value: Toyoda's "displacement control circuit... controls the pump displacement Dp" (Col. 4, lines 63-64) based on the output of the load control, thereby delivering the selected pump power value.

Therefore, Claim 1 of US 9133837 is rendered obvious by US 5,050,379 A.

Obviousness of Dependent Claims 2-10

Given the obviousness of Claim 1, the dependent claims would also be obvious when combined with common knowledge in the art.

• Claim 2: Toyoda's Figure 2, which plots permissible engine load versus engine speed, shows that allowable load (power) generally increases with engine speed, consistent with allowable power being less at lower engine speeds. (Col. 5, lines 34-36).
• Claim 3: A POSITA would understand that an "allowable power value" or "permissible engine load" (as in Toyoda) would naturally be a function of the maximum rated power of the pump and engine, as these are inherent physical limits.
• Claims 4, 5, 7, 8, and 18, 19: Toyoda explicitly discusses "target pump displacement Dd" (desired displacement) based on demand and restricting "pump displacement" to match the "permissible engine load Tp" (allowable displacement). (Col. 4, lines 49-60). A POSITA would understand that desired and allowable power are directly translatable to desired and allowable displacement for a variable displacement pump.
• Claims 6 and 20: Toyoda explicitly detects "pump discharge pressure P" (Col. 4, line 52). The calculation of allowable displacement as a function of allowable power (or torque) divided by detected discharge pressure (d_allowable = f(T_allowable / P_d)) is a fundamental hydraulic principle well-known to a POSITA.
• Claim 9: Toyoda's system is for "hydraulic actuators" (FIG. 1) on a "hydraulic work machine" (Col. 1, lines 6-7), clearly demonstrating an implement operable by the pump's fluid.
• Claim 10: Toyoda describes a continuous control system that repeatedly detects parameters and adjusts the pump, implying continuous readjustment in response to changes in engine speed or desired power. (Col. 4, lines 49-65).

Obviousness of Independent Claim 11 (Hydraulic system)

Claim 11 of US 9133837 recites a hydraulic system with specific components and a control system configured for the method steps.

• Engine, variable displacement pump, implement, and engine speed sensor: Toyoda explicitly discloses an "engine 1," a "variable displacement hydraulic pump 2," "hydraulic actuators 3a, 3b" (implements), and an "engine speed sensor 4" (FIG. 1, Col. 4, lines 52-53). The function of hydraulic power being a function of piston displacement is inherent to variable displacement pumps.
• Control system configured for identifying allowable power from a map, determining desired power, and adjusting displacement to deliver the lower of the two: Toyoda's "load control circuit 7" and "displacement control circuit 9" (FIG. 1, Col. 4) collectively constitute a control system that performs precisely these functions as detailed in the Claim 1 analysis above.

Therefore, Claim 11 of US 9133837 is rendered obvious by US 5,050,379 A.

Obviousness of Dependent Claims 12-14

• Claim 12: Toyoda's system is for a "hydraulic work machine" (Col. 1, lines 6-7), making this claim obvious.
• Claim 13: User input for hydraulic machines is conventionally provided via levers. A POSITA would find it obvious to use a lever to direct the desired power signal to the control system.
• Claim 14: As discussed for Claim 10, Toyoda's continuous control operation inherently involves readjustment.

Obviousness of Independent Claim 15 (Method of operating a machine)

Claim 15 of US 9133837 is substantially similar to Claim 1, rephrased for operating a machine.

• Detecting a user input signal indicative of a desired power value: Taught by Toyoda's sensing of "demand for the hydraulic pump".
• Sensing a speed of the engine: Taught by Toyoda's "engine speed sensor".
• Choosing an allowable power value from a map: Taught by Toyoda's determination of "permissible engine load... by using a map".
• Adjusting the pump to direct a lower of the allowable power value and the desired power value: Taught by Toyoda's load control reducing pump displacement to restrict engine load to the permissible level.

Therefore, Claim 15 of US 9133837 is rendered obvious by US 5,050,379 A.

Obviousness of Dependent Claims 16-20

These claims are rendered obvious for the same reasons as the corresponding dependent claims of Claim 1, in view of US 5,050,379 A and common general knowledge in the art.

Alternative Reference: US 5,525,043 A to Lukich (Caterpillar Inc.)

US Patent 5,525,043 A, titled "Hydraulic power control system," is explicitly discussed in the background of US 9133837. While US 9133837 seeks to address the "complexity" and cost of Lukich's system, the method and system claims of US 9133837 are drafted broadly and do not inherently exclude such complexity or specify a "minimal number of operating parameters" as a claim limitation.

Lukich discloses:

• Detecting engine speed: Using an "engine speed sensor 58". (Col. 4, lines 60-61 of US5525043A).
• Determining desired power value based on user input: Responding to "operator input devices such as control levers 12" (Col. 3, lines 60-61 of US5525043A), which provide a "pump output control signal indicative of a desired implement demand" (Col. 4, lines 52-54 of US5525043A).
• Identifying an allowable power value from a map: Employing a "power limit curve (FIG. 3)" (Col. 5, lines 34-35 of US5525043A) which plots "pump output pressure versus engine speed at a maximum permissible load" (Col. 3, lines 16-18 of US5525043A). This power limit curve serves as a map for allowable power.
• Selecting the lower of allowable and desired power: Lukich's "pump output control logic 50" (Col. 4, line 43 of US5525043A) determines the pump output to accommodate the lowest of various pressure limiting signals, including the "maximum permissible load" (allowable) and the "desired implement demand" (desired). (Col. 4, lines 57-59 of US5525043A). The system reduces pump output when the load exceeds a predefined level. (Col. 3, lines 33-35 of US5525043A).
• Adjusting the pump: Lukich's system reduces the "displacement of the variable displacement pump" (Col. 3, lines 33-34 of US5525043A).

Motivation to combine with Lukich:
A POSITA would be motivated to use the teachings of Lukich, which addresses the same problem of preventing engine lug in hydraulic systems, to control a variable displacement pump. The "power limit curve" in Lukich is functionally equivalent to the "map" recited in the claims of US 9133837. Any additional details not explicitly mentioned in Lukich's claims (e.g., specific lever input for desired power, or the precise calculation of allowable displacement from allowable power and pressure) would be considered common knowledge in the hydraulic control art at the time of the invention.

Conclusion on Obviousness

All independent claims (1, 11, and 15) and their dependent claims (2-10, 12-14, 16-20) of US Patent 9133837 are rendered obvious by US Patent 5,050,379 A (Toyoda). Toyoda comprehensively discloses the method steps and system components for controlling a variable displacement pump based on engine speed, a map for allowable power, and desired user input, by selecting the lower of the allowable and desired power.

Alternatively, US Patent 5,525,043 A (Lukich), a prior art reference from the same assignee and discussed in the background of US 9133837, also renders the claims obvious. Lukich teaches the core elements of detecting engine speed, determining desired power from user input, identifying allowable power from a power limit curve (a map), selecting the lower of these values, and adjusting the pump displacement.

A POSITA would have been motivated to combine these teachings (from either Toyoda alone, or Lukich in combination with common knowledge) because they address the common and recognized problem of efficiently controlling hydraulic systems to prevent engine lug and stall. The methods and systems described in the prior art provide direct and analogous solutions to the problems addressed by US 9133837.