System and method for controlling the speed of an engine providing power to a concrete mixing drum

• US 6,286,987 B1
• Filed: 10/29/1999
• Issued: 09/11/2001
• Est. Priority Date: 10/29/1999
• Status: Expired due to Term

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Banks, Donald L., Goode, Charles E.
• Primary Examiner(s): Cooley, Charles E.
• Application Number:
  US09/430,220
• Time in Patent Office: 683 Days
• Field of Search: 366/53-59, 366/60, 366/61, 366/220-231, 366/601, 123/352, 417/12, 417/34
• US Class Current: 366/60
• CPC Class Codes: B28C 5/4206 Control apparatus; Drive systems, e.g. coupled to the vehicle drive-system

Abstract

A system for controlling the speed of an engine in a vocational application is implemented within a mobile cement mixer. The system permits operation of the engine at a high rpm PTO speed to drive the mixing drum at a recommended speed for optimal full mixing of aggregate within the drum. The system maintains the engine at this high rpm only for a predetermined time period necessary for full mixing. After expiration of the time period, the system directs the engine governor to drop the engine speed to low idle, thereby preventing overworking of the cement, reducing the abrasive effect of the aggregate on the interior of the mixing drum, and improving engine fuel economy. In one embodiment, the system permits operator entry of drum rotation speed and total drum revolutions, which are then used to calculate the time period value. In another embodiment, the input is number of drum rotations and the system uses a signal from a drum rotation counter to control the high rpm—low idle speed change of the engine.

Claims

1. A system for controlling the speed of an engine providing power to a mixing drum, said system comprising:

a control module operable to control the speed of the engine at a first speed sufficient to power the mixing drum and at a lower second speed;

a timer for measuring the elapsed time that the control module controls the engine speed at said first speed;

a controller operable to direct the control module to control the engine speed at said second speed when said elapsed time equals a threshold value;

a counter for generating a counting signal indicative of the number of revolutions of the mixing drum; and

means within the timer for calculating the elapsed time from the counting signal.

2. The system for controlling the speed of an engine according to claim 1, wherein said first speed is an engine high rpm and said second speed is an engine low idle speed.

3. The system for controlling the speed of an engine according to claim 1, wherein said first speed is a speed sufficient for desired mixing of material contained in the mixing drum, and said second speed is an engine idle speed.

4. The system for controlling the speed of an engine according to claim 3, wherein said threshold value is a time limit for desired mixing of the material when the engine is operating at said first speed.

5. The system for controlling the speed of an engine according to claim 1, wherein said controller includes input means for operator input of said threshold-value.

6. The system for controlling the speed of an engine according to claim 5, wherein said input means includes a control panel associated with the engine and accessible by the operator for data entry.

7. The system for controlling the speed of an engine according to claim 5, wherein said input means includes an input tool selectively engageable with said controller to transmit data thereto.

8. The system for controlling the speed of an engine according to claim 1, in which the driven component is a mixing drum, wherein said controller includes:

input means for operator input of a speed value corresponding to a desired rotation speed for the mixing drum and a revolutions value corresponding to a desired total number of revolutions of the mixing drum; and

means for calculating said threshold value from said speed value and said revolutions value.

9. The system for controlling the speed of an engine according to claim 8, wherein said input means includes a control panel associated with the engine and accessible by the operator for data entry.

10. The system for controlling the speed of an engine according to claim 9, wherein said control panel includes at least one control switch operable to increment and to decrement at least one of said speed value and said revolutions value by a fixed increment.

11. The system for controlling the speed of an engine according to claim 8, wherein the controller further includes:

a memory for storing a range of acceptable values for at least one of said speed value and said revolutions value; and

a comparator operable to compare at least one of said operator input speed value and revolutions value to said range of acceptable values, said comparator generating an error signal if said at least one value is outside said range of acceptable values.

12. The system for controlling the speed of an engine according to claim 8, wherein said input means includes an input tool selectively engageable with said controller to transmit data thereto.

13. The system for controlling the speed of an engine according to claim 1, wherein said controller is responsive to an external signal to direct the control module to control the engine speed at said first speed.

14. In a concrete mixing vehicle having an engine driving a motor operable to rotate a mixing drum, the operating speed of the engine being controlled by signals from an engine control module (ECM), the ECM operable to control the engine speed at an idle speed and at a mixing speed corresponding to a speed of the mixing drum sufficient to mix material contained within the drum, a system for controlling engine speed comprising:

means for determining an elapsed time that the ECM has controlled the engine speed at the mixing speed;

means for directing the ECM to control the engine speed at the idle speed when said elapsed time equals a threshold value; and

a counter for generating a counting signal indicative of the number of revolutions of the mixing drum;

wherein the means for determining an elapsed time includes means for calculating the elapsed time from the counting signal.

15. The system for controlling engine speed according to claim 14, wherein said means for directing is responsive to an external signal to direct the ECM to control the engine speed at said mixing speed.

16. In a concrete mixing vehicle having an engine driving a motor operable to rotate a mixing drum, the operating speed of the engine being controlled by signals from an engine control module (ECM), the ECM operable to control the engine speed at an idle speed and at a mixing speed corresponding to a speed of the mixing drum sufficient to mix material contained within the drum, a system for controlling engine speed comprising:

means for determining an elapsed time that the ECM his controlled the engine speed at the mixing speed; and

means for directing the ECM to control the engine speed at the idle speed when said elapsed time equals a threshold value including input means for operator input of a speed value corresponding to a desired rotation speed for the mixing drum and a revolutions value corresponding to a desired total number of revolutions of the mixing drum, and means for calculating the threshold value from said speed value and said revolutions value.

17. The system for controlling engine speed according to claim 16, wherein said input means includes a control panel associated with the vehicle and accessible by the operator for data entry.

18. The system for controlling engine speed according to claim 16, wherein said input means includes an input tool selectively engageable with said means for directing to transmit data thereto.

19. The system for controlling engine speed according to claim 16, wherein said means for directing is responsive to an external signal to direct the ECM to control the engine speed at said mixing speed.