초록 ▼

A control system for a machine is disclosed. The control system may have a pump, a low pressure reservoir, and at least one actuator connected to receive fluid pressurized by the pump and discharge fluid to the low pressure reservoir. The control system may also have a bypass passage situated to all

A control system for a machine is disclosed. The control system may have a pump, a low pressure reservoir, and at least one actuator connected to receive fluid pressurized by the pump and discharge fluid to the low pressure reservoir. The control system may also have a bypass passage situated to allow fluid to bypass the at least one actuator, and a warmup valve disposed within the bypass passage and being movable between a flow-passing position and a flow-blocking position. The control system may further have a hydraulic temperature sensor configured to generate a signal indicative of a temperature of the fluid, and a controller in communication with the pump, the warmup valve, and the hydraulic temperature sensor. The controller may be configured to move the warmup valve to the flow-passing position, fix a displacement position of the pump, and adjust an input speed of the pump in response to the signal.

대표청구항 ▼

1. A machine control system, comprising: a pump driven to pressurize fluid, the pump being driven by an engine to pressurize the fluid;a low pressure reservoir;at least one actuator connected to receive fluid pressurized by the pump and discharge fluid to the low pressure reservoir;a bypass passage

1. A machine control system, comprising: a pump driven to pressurize fluid, the pump being driven by an engine to pressurize the fluid;a low pressure reservoir;at least one actuator connected to receive fluid pressurized by the pump and discharge fluid to the low pressure reservoir;a bypass passage situated to allow fluid pressurized by the pump to bypass the at least one actuator and flow to the low pressure reservoir;a warmup valve disposed within the bypass passage and being movable between a flow-passing position and a flow-blocking position;a hydraulic temperature sensor configured to generate a signal indicative of a temperature of the fluid; anda controller in communication with the pump, the warmup valve, and the hydraulic temperature sensor, the controller being configured to move the warmup valve to the flow-passing position, fix a displacement position of the pump, and adjust an input speed of the pump in response to the signal only after a temperature of the engine has increased to a desired engine temperature or the engine has driven the pump for a period of time. 2. The machine control system of claim 1, wherein the warmup valve provides a restriction on the fluid passing through the warmup valve to warm the fluid. 3. The machine control system of claim 1, wherein the controller is configured to fix the displacement of the pump at a maximum displacement position when the signal indicates a temperature of the fluid less than a desired temperature. 4. The machine control system of claim 3, wherein the desired temperature is about 30° C. 5. The machine control system of claim 3, wherein the controller is configured to set the input speed of the pump to a speed greater than a low-idle speed when the signal indicates the temperature of the fluid less than the desired temperature. 6. The machine control system of claim 1, wherein the desired engine temperature is about equal to 25° C., and the period of time is about equal to five minutes. 7. The machine control system of claim 1, wherein the at least one actuator includes a plurality of actuators and the machine control system further includes: a valve stack;a plurality of control valves disposed within the valve stack and configured to selectively regulate fluid flow to and from the plurality of actuators;a supply passage extending from the pump through the valve stack to communicate with each of the plurality of control valves in parallel; anda drain passage extending through the valve stack to the low pressure reservoir and fluidly communicating with each of the plurality of control valves in parallel, wherein the bypass passage fluidly connects the supply passage to the drain passage to bypass fluid around the plurality of control valves. 8. The machine control system of claim 7, wherein the supply passage is disposed within the valve stack on an opposing side of the plurality of control valves from the drain passage. 9. The machine control system of claim 8, wherein the warmup valve is located at an end of the valve stack. 10. A machine control system, comprising: a pump driven to pressurize fluid;a low pressure reservoir;at least one actuator connected to receive fluid pressurized by the pump and discharge fluid to the low pressure reservoir;a bypass passage situated to allow fluid pressurized by the pump to bypass the at least one actuator and flow to the low pressure reservoir;a warmup valve disposed within the bypass passage and being movable between a flow-passing position and a flow-blocking position;a hydraulic temperature sensor configured to generate a signal indicative of a temperature of the fluid; anda controller in communication with the pump, the warmup valve, and the hydraulic temperature sensor, the controller being configured to: move the warmup valve to the flow-passing position, fix a displacement position of the pump, and adjust an input speed of the pump in response to the signal;fix the displacement of the pump at a maximum displacement position when the signal indicates a temperature of the fluid less than a desired temperature;set the input speed of the pump to a speed greater than a low-idle speed when the signal indicates the temperature of the fluid less than the desired temperature; andincrement the input speed of the pump over a period of time when the signal indicates the temperature of the fluid less than the desired temperature. 11. The machine control system of claim 10, wherein the controller is configured to increment the input speed of the pump to a maximum input speed and maintain the maximum input speed of the pump for a period of time when the signal indicates the temperature of the fluid less than the desired temperature. 12. The machine control system of claim 11, wherein the controller is configured to return the input speed of the pump to the low-idle speed, reduce a displacement of the pump to a minimum displacement position, and move the warmup valve to the flow-blocking position when the temperature of the fluid increases to about the desired temperature or when operation of the pump has been maintained at the maximum input speed for a period of time. 13. The machine control system of claim 10, wherein the controller is configured to increment the input speed of the pump by about 100 rpm every sixty seconds. 14. A method of warming a machine control system, comprising: displacing an amount of fluid at a displacement rate to pressurize the fluid;directing pressurized fluid to an actuator;sensing a temperature of the fluid;in response to the sensed temperature, selectively directing pressurized fluid to bypass the actuator, fixing the displacement amount, and adjusting the displacement rate,the displacement amount being fixed, the pressurized fluid being directed to bypass the actuator, and the displacement rate being periodically incremented from a low-idle rate when the sensed temperature is less than about 30° C.,incrementing the displacement rate to a maximum rate and maintaining the displacement rate at the maximum rate for a period of time when the sensed temperature is less than about 30° C.; andreturning the displacement rate to a low-idle rate, reducing the displacement amount to a minimum amount, and blocking the pressurized fluid from bypassing the actuator when the temperature of the fluid increases above about 30° C. or the displacement rate has been maintained at the maximum rate for the period of time. 15. A method of warming a machine control system, comprising: displacing an amount of fluid at a displacement rate to pressurize the fluid;directing pressurized fluid to an actuator;driving the displacing of fluid with an engine;sensing a temperature of the engine,sensing a temperature of the fluid; andin response to the sensed fluid temperature, selectively directing pressurized fluid to bypass the actuator, fixing the displacement amount, and adjusting the displacement rate only after a temperature of the engine has increased to a desired engine temperature or the engine has driven the displacing of fluid for a period of time. 16. A machine, comprising: an engine;an engine temperature sensor configured to generate an engine temperature signal indicative of a temperature of the engine;a pump driven by the engine to pressurize fluid;a low pressure reservoir;a work tool;at least one actuator connected to receive fluid pressurized by the pump and discharge fluid to the low pressure reservoir to move the work tool;a valve stack having: a supply passage fluidly connected to the pump;a drain passage fluidly connected to the drain passage;at least one control valve fluidly connected between the supply and the drain passages and being configured to selectively regulate fluid flow to and from the at least one actuator;a bypass passage fluidly connecting the supply and drain passages; anda warmup valve disposed within the bypass passage and being movable between a flow-passing position and a flow-blocking position;a hydraulic temperature sensor configured to generate a hydraulic temperature signal indicative of a temperature of the fluid; anda controller in communication with the engine, the engine temperature sensor, the pump, the warmup valve, and the hydraulic temperature sensor, the controller being configured to move the warmup valve to the flow-passing position, fix a displacement position of the pump, and adjust periodically increment a speed of the engine in response to the hydraulic temperature signal only after the engine temperature signal indicates a temperature of the engine above a desired engine temperature or the engine has operated for a period of time.