Combination speed limiter and transmission interlock system

• US 6,595,897 B1
• Filed: 03/01/2002
• Issued: 07/22/2003
• Est. Priority Date: 03/01/2002
• Status: Expired due to Fees

• Current Assignee: Briggs & Stratton Corporation
• Original Assignee: Briggs & Stratton Corporation
• Inventors: Ketelhohn, Charles Hardy, Dykstra, Richard A.
• Primary Examiner(s): Wright; Dirk
• Application Number:
  US10/086,607
• Time in Patent Office: 508 Days
• Field of Search: 477/99 440/75
• US Class Current: 477/99
• CPC Class Codes: F02D 2041/2048 said control involving a limitation, e.g. applying current or voltage limits
• CPC Class Codes: F02D 2400/18 Packaging of the electronic circuit in a casing
• CPC Class Codes: F02D 41/0225 in relation with the gear ratio or shift lever position
• CPC Class Codes: F02D 41/3005 Details not otherwise provided for
• CPC Class Codes: F02N 11/103 according to the vehicle transmission or clutch status
• CPC Class Codes: F02P 11/02 Preventing damage to engines or engine-driven gearing
• CPC Class Codes: F02P 9/005 by weakening or suppression of sparks to limit the engine speed

Abstract

A combination speed limiter and transmission interlock system for an engine-transmission power train that includes an internal combustion engine and a transmission, the power train of the type used to power outboard engines and the like. The system utilizes fewer connections, is less expensive, is expected to be more reliable, utilizes a single housing, is easier to manufacture, and uses fewer components than a power train that utilizes separate speed limiter and transmission interlock modules.

Claims

1. A combination speed limiter and transmission interlock system for an engine-transmission power train, the engine having a coil that outputs an ignition pulse and an igniter that ignites an air-fuel mixture, the transmission being interconnected to a switch that indicates one of a neutral position of the transmission and an in-gear position of the transmission, the combination speed limiter and transmission interlock system comprising:

an ignition control circuit, connected in circuit with the coil, that prevents the igniter from igniting the air-fuel mixture;

a speed control circuit, connected in circuit with the ignition control circuit, that causes the ignition control circuit to prevent the igniter from igniting the air-fuel mixture when the engine exceeds a limit speed; and

a start control circuit, connected in circuit with the switch and the ignition control circuit, that causes the ignition control circuit to prevent the igniter from igniting the air-fuel mixture when the transmission switch indicates the in-gear position of the transmission during starting of the engine.

2. The system of claim 1, wherein the engine-transmission power train includes an outboard motor.

3. The system of claim 1, further comprising a single housing that substantially contains the combination speed limiter and transmission interlock system.

4. The system of claim 3, further comprising a power node that is electrically coupled to the coil by an electrical conduit that extends external of the housing.

5. The system of claim 3, further comprising a ground node that is electrically coupled to ground by an electrical conduit that extends external to the housing.

6. The system of claim 3, wherein the start control circuit is electrically coupled to the switch by two electrical conduits that extend external to the housing.

7. The system of claim 1, wherein the ignition control circuit further comprises a second switch that limits the voltage of the ignition pulse to prevent the igniter from igniting the air-fuel mixture.

8. The system of claim 7, wherein the second switch includes a silicon controlled rectifier.

9. The system of claim 7, wherein the second switch includes a transistor.

10. The system of claim 7, wherein the second switch limits the voltage of the ignition pulse by shorting the ignition pulse to a ground.

11. The system of claim 7, wherein the ignition control circuit further comprises a current limiting resistor, and

wherein the second switch limits the voltage of the ignition pulse by shunting the ignition pulse through the current limiting resistor to ground.

12. The system of claim 7, further comprising a prevention circuit that prevents transient signals from turning ON the second switch.

13. The system of claim 12, wherein the prevention circuit includes

a second electrical storage device, and

a resistor that allows the second electrical storage device to discharge between operating cycles of the engine.

14. The system of claim 7, wherein the speed control circuit causes the ignition control circuit to prevent the igniter from igniting the air-fuel mixture by turning ON the second switch when the engine exceeds the limit speed.

15. The system of claim 14, wherein the speed control circuit further comprises an electrical storage device that receives electrical energy of the ignition pulse, and

wherein the second switch is turned ON when the speed circuit receives electrical energy from the electrical storage device that is above a predetermined value.

16. The system of claim 15, wherein the speed circuit further comprises a third switch that is responsive to the electrical energy received from the electrical storage device, wherein the predetermined value is set by the third switch.

17. The system of claim 7, wherein the start control circuit causes the ignition control circuit to prevent the igniter from igniting the air-fuel mixture by turning ON the second switch when the first switch indicates the in-gear position of the transmission during starting of the engine.

18. The system of claim 1, wherein the speed control circuit further comprises a limit speed resistor that can be set to establish the value of the limit speed of the engine.

19. The system of claim 18, wherein the limit speed resistor includes a variable resistor.

20. The system of claim 1, wherein the speed control circuit further comprises an electrical storage device that receives electrical energy of the ignition pulse.

21. The system of claim 20, wherein the electrical storage device receives electrical energy of the ignition pulse during a leading half-cycle of the ignition pulse.

22. The system of claim 20, wherein the speed control circuit further comprises a speed circuit that includes a second switch that limits the voltage of the electric storage device to a predetermined value regardless of the voltage of the ignition pulse.

23. The system of claim 1, further comprising an inhibitor control circuit, connected in circuit with the ignition control circuit and the start control circuit, that prevents the start control circuit from causing the ignition control circuit to prevent the igniter from igniting the air-fuel mixture when the transmission switch indicates the in-gear position of the transmission during running of the engine.

24. The system of claim 23, wherein the inhibitor control circuit further comprises a second switch connected such that the inhibitor control circuit is activated by turning ON the second switch.

25. The system of claim 24, wherein the second switch includes a semiconductor switch.

26. The system of claim 24, wherein the second switch is turned ON when a minimum engine speed is reached.

27. The system of claim 26, wherein the value of the minimum engine speed is the engine speed required to drive the transmission.

28. The system of claim 26, wherein the value of the minimum engine speed is adjustable.

29. The system of claim 23, further comprising a reset circuit that resets the inhibitor control circuit when the engine is shut down.

30. The system of claim 1, further comprising a programmable device connected in circuit with the ignition control circuit,

wherein the speed control circuit includes a speed circuit that provides the programmable device with a speed signal corresponding to the speed of the engine, and

wherein the start control circuit includes a switch circuit that provides the programmable device with a position signal corresponding to one of the neutral position of the transmission and the in-gear position of the transmission.

31. The system of claim 30, wherein the programmable device utilizes the speed signal to calculate the speed of the engine.

32. The system of claim 30, wherein the programmable device utilizes the position signal to determine if the transmission is in the neutral position.

33. The system of claim 30, wherein the programmable device outputs a limit signal to the ignition control circuit to cause the ignition control circuit to prevent the igniter from igniting the air-fuel mixture when at least one predetermined condition exists.

34. The system of claim 33, wherein the at least one predetermined condition exists when the value of the speed of the engine is above the value of a maximum operational limit speed.

35. The system of claim 33, wherein the at least one predetermined condition exists when the transmission is in the in-gear position and the value of the speed of the engine is below the value of a minimum operational engine speed.

36. The system of claim 33, wherein the at least one predetermined condition exists when the transmission is in the neutral position and the value of the speed of the engine is above the value of a minimum operational engine speed.

37. The system of claim 33, wherein the ignition control circuit further comprises a second switch that turns ON in response to the limit signal.

38. The system of claim 37, wherein the second switch includes a sensitive gate triac.

39. The system of claim 37, wherein the second switch includes a transistor.

40. The system of claim 30, wherein the programmable device outputs a limit signal to the ignition control circuit to prevent the ignition control circuit from preventing the igniter from igniting the air-fuel mixture when at least one predetermined condition exists.

41. The system of claim 40, wherein the at least one predetermined condition exists when the value of the speed of the engine is below the value of a maximum operational limit speed and the transmission is in the neutral position.

42. The system of claim 40, wherein the at least one predetermined condition exists when the transmission is in the in-gear position and the value of the speed of the engine is below the value of a maximum operational engine speed.

43. The system of claim 30, further comprising a power supply circuit configured to provide a power signal to the programmable device.

44. The system of claim 43, further comprising a brown-out circuit that provides a reset signal to the programmable device when the power signal drops below a predetermined value.

45. The system of claim 30, wherein the speed circuit includes an electrical storage device that is responsive to a center half-cycle of the ignition pulse and that discharges when the center half-cycle is detected, thereby generating the speed signal.

46. The system of claim 1, further comprising a device that outputs an operating hours signal corresponding to the number of operating hours of the power train.

47. The system of claim 46, further comprising a single housing that substantially contains the combination speed limiter and transmission interlock system, and wherein the operating hours signal is a voltage that can be measured external to the housing using a volt meter.

48. The system of claim 46, further comprising a memory device associated with the first device that stores data corresponding to a number of operating hours of the power train.