High ambient temperature propulsion speed control of a self-propelled agricultural product applicator

Patent metadata

Field	Value
Publication number	US-10393261-B2
Application number	US-201715833089-A
Country	US
Kind code	B2
Filing date	Dec 6, 2017
Priority date	Dec 6, 2017
Publication date	Aug 27, 2019
Grant date	Aug 27, 2019

Abstract

A system, apparatus and method are provided for limiting operating speed at high temperatures of a self-propelled, agricultural product applicator having a hydraulic drive system including a pump supplying pressurized hydraulic fluid to a variable-displacement hydraulic motor operatively connected for propelling the applicator. A temperature sensor detects a temperature of the pressurized hydraulic fluid in the hydraulic system. A propel controller is operatively connected between the temperature sensor and the propulsion motor and configured for limiting displacement of the propulsion motor according to one or more predetermined de-rated conditions resulting in reduced motor speed, in accordance with a predetermined schedule, when predetermined motor de-rating activation temperature limits of the hydraulic fluid are detected by the temperature sensor. The controller is further configured for providing a de-rated condition warning signal prior to limiting displacement of the propulsion motor.

First claim

We claim:

1. A system for limiting operating speed at high temperatures in a hydraulically-driven, self-propelled, agricultural product applicator having a hydraulic system including a pump supplying pressurized hydraulic fluid to a variable-displacement hydraulic motor operatively connected for propelling the applicator, the system comprising:
a temperature sensor operatively connected for detecting a temperature of the pressurized hydraulic fluid in the hydraulic system; and
a propel controller operatively connected to the temperature sensor and the propulsion motor and configured for limiting displacement of the propulsion motor according to a predetermined de-rated condition resulting in reduced motor speed, when a predetermined motor de-rating activation temperature limit of the hydraulic fluid is detected by the temperature sensor.

2. The speed limiting system of claim 1 , wherein the controller is further configured to provide a warning signal prior to limiting displacement of the propulsion motor, when a predetermined warning activation temperature limit of the hydraulic fluid is detected by the temperature sensor, with the warning activation temperature being lower than the motor de-rating activation temperature.

3. A system for limiting operating speed at high temperatures in a hydraulically-driven, self-propelled, agricultural product applicator having a hydraulic system including a pump supplying pressurized hydraulic fluid to a variable-displacement hydraulic motor operatively connected for propelling the applicator, the system comprising:
a temperature sensor operatively connected for detecting a temperature of the pressurized hydraulic fluid in the hydraulic system; and
a propel controller operatively connected between the temperature sensor and the propulsion motor and configured for limiting displacement of the propulsion motor according to a predetermined de-rated condition resulting in reduced motor speed, when a predetermined motor de-rating activation temperature limit of the hydraulic fluid is detected by the temperature sensor;
wherein the propulsion motor includes a swashplate for controlling motor rotational speed as a function of swashplate angle, and the propel controller is operatively connected for limiting motor speed by limiting swashplate angle in the de-rated condition.

4. The speed limiting system of claim 3 , wherein the propulsion motor operates at maximum speed when the swashplate angle and corresponding motor displacement are at minimum values, and the controller is operatively connected to control the swashplate angle at an angle greater than the minimum value of swashplate angle in the de-rated condition, to thereby limit operation of the propulsion motor to a speed less than the maximum speed of the motor whenever the controller is limiting the motor to operation in the de-rated condition.

5. A system for limiting operating speed at high temperatures in a hydraulically-driven, self-propelled, agricultural product applicator having a hydraulic system including a pump supplying pressurized hydraulic fluid to a variable-displacement hydraulic motor operatively connected for propelling the applicator, the system comprising:
a temperature sensor operatively connected for detecting a temperature of the pressurized hydraulic fluid in the hydraulic system; and
a propel controller operatively connected between the temperature sensor and the propulsion motor and configured for limiting displacement of the propulsion motor according to a predetermined de-rated condition resulting in reduced motor speed, when a predetermined motor de-rating activation temperature limit of the hydraulic fluid is detected by the temperature sensor;
wherein the propel controller is further configured for maintaining the propulsion motor in the de-rated condition until the temperature sensor detects that the hydraulic fluid temperature has dropped to a predetermined motor de-rating de-activation temperature.

6. The speed limiting system of claim 5 , wherein the controller is further configured for de-rating the propulsion motor according to a derating schedule having at least a first and a second de-rated condition with corresponding first and second reductions in displacement of the propulsion motor in response to a schedule of respective first and second motor de-rating activation and de-activation temperatures.

7. The speed limiting system of claim 6 , wherein the controller is further configured to maintain the warning signal prior until a predetermined warning de-activation temperature limit of the hydraulic fluid is detected by the temperature sensor, with the warning de-activation temperature being lower than the warning activation temperature.

8. The speed limiting system of claim 5 , wherein the controller is further configured to provide a warning signal prior to reducing displacement of the propulsion motor, when a predetermined warning activation temperature limit of the hydraulic fluid is detected by the temperature sensor, with the warning activation temperature being lower than the motor de-rating activation temperature.

9. The speed limiting system of claim 8 , wherein the controller is configured for providing and maintaining the warning signal, and for reducing and maintaining propulsion motor displacement in accordance with a schedule of predetermined temperatures as determined by the temperature sensor, in which:
the controller sends the warning at a warning activation temperature, and maintains the warning until the temperature sensor detects that the hydraulic fluid has cooled to a warning de-activation temperature that is lower than the warning activation temperature;
the controller limits motor displacement to a first de-rated condition in a manner providing a first reduction in operating speed of the applicator at a first motor de-rating activation temperature that is higher than the warning activation temperature, and maintains the limited motor displacement in the first de-rated condition until the temperature sensor detects that the hydraulic fluid has cooled to a first motor de-rating de-activation temperature that is lower than the first motor de-rating activation temperature; and
the controller limits motor displacement to a second de-rated condition in a manner providing a second reduction in operating speed of the applicator at a second motor de-rating activation temperature that is higher than the first motor de-rating activation temperature, and maintains the limited motor displacement in the second de-rated condition until the temperature sensor detects that the hydraulic fluid has cooled to a second motor de-rating de-activation temperature that is lower than the second motor de-rating activation temperature.

10. A self-propelled, hydraulically-driven, agricultural product applicator having an engine and a hydrostatic drive system, the hydrostatic drive system including a propulsion pump driven by the engine at a fixed ratio of engine speed and supplying pressurized hydraulic fluid to a variable-displacement hydraulic propulsion motor operatively connected for propelling the applicator, and a system for limiting operating speed of the hydraulically-driven, self-propelled, agricultural product applicator at high temperatures, where the system for limiting speed at high temperatures comprises:
a temperature sensor operatively connected for detecting a temperature of the pressurized hydraulic fluid in the hydraulic system; and
a propel controller operatively connected to the temperature sensor and the propulsion motor and configured for limiting displacement of the propulsion motor according to a predetermined de-rated condition resulting in reduced motor speed, when a predetermined

Assignees

• Cnh Ind America Llc
• Danfoss Power Solutions Inc

Inventors

• Hafvenstein David J
• Nielsen Simon L

Classifications

• F16H61/4192

  Detecting malfunction or potential malfunction, e.g. fail safe · CPC title

• F16H59/72

  dependent on oil characteristics, e.g. temperature, viscosity · CPC title

• F16H61/47

  for achieving a target output speed · CPC title

• F16H2061/124

  Limiting the input power, torque or speed · CPC title

• A01M21/04

  Apparatus for destruction by steam, chemicals, burning, or electricity {(apparatus for burning A01M15/00)} · CPC title