Safety limiter for powered vehicles

• US 6,253,143 B1
• Filed: 01/26/1999
• Issued: 06/26/2001
• Est. Priority Date: 01/26/1999
• Status: Expired due to Term

• Current Assignee: Veritas DGC, Inc. (CGG)
• Original Assignee: Veritas DGC, Inc. (CGG)
• Inventors: Silvernagle, Darin, Lafont, Don
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US09/237,319
• Time in Patent Office: 882 Days
• Field of Search: 701/93, 701/102, 701/110, 701/104, 180/173, 340/438, 340/439, 340/430, 340/441, 123/406.16, 123/406.65, 123/609, 123/333, 123/335, 123/339.24, 123/339.25, 123/361, 123/406.35, 123/406.37, 123/406.57, 123/373, 123/357, 123/449, 123/320, 123/319, 123/339.14, 123/351, 123/406.23, 123/406.64
• US Class Current: 701/93
• CPC Class Codes: B60K 31/04 and means for comparing one electrical quantity, e.g. voltage, pulse, waveform, flux, or the like, with another quantity of a like kind, which comparison means is involved in the development of an electrical signal which is fed into the controlling means
• CPC Class Codes: B60W 30/146 Speed limiting
• CPC Class Codes: B60Y 2200/12 Motorcycles, Trikes; Quads; Scooters
• CPC Class Codes: F02D 2200/501 Vehicle speed
• CPC Class Codes: F02P 5/1504 with particular means during a transient phase, e.g. acceleration, deceleration, gear change during starting F02P5/1506
• CPC Class Codes: F02P 9/005 by weakening or suppression of sparks to limit the engine speed
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A vehicle control unit is disclosed which can be coupled between a tachometer sensor and an electronic ignition system on a vehicle. The unit is also coupled to a speedometer sensor to measure the vehicle'"'"'s speed. The vehicle control unit limits the vehicle speed by modifying the tachometer signal from the tachometer sensor and providing the modified tachometer signal to the ignition system. The tachometer signal is a pulse train which is used by the electronic ignition system to determine ignition timing. The vehicle control unit limits both ground speed and engine speed by suppressing pulses from the original tachometer signal to prevent the combustion of fuel and thereby reduce engine power when the ground or engine speeds exceed predetermined limits. The vehicle control unit is microcontroller-based and preferably includes a logging function and an acceleration sensor. The microcontroller is coupled to the acceleration sensor to detect the peak accelerations experienced by the vehicle. The microcontroller stores peak accelerations above a predetermined limit, along with excessive ground and engine speeds, as part of a fault record a nonvolatile memory. The records can be examined by management personnel to identify reckless vehicle operators. Corrective action can then be taken to protect personnel and equipment. A handheld programming unit is also disclosed herein for programming the predetermined limits and for retrieving fault records. The programming unit can display and summarize fault records, and can be used to transport the fault information to a central computer system for archiving and more extensive analysis.

Claims

1. A vehicle which comprises:

an engine configured to convert fuel into power for a drive mechanism, wherein the engine includes an electronic ignition system;

a tachometer sensor coupled to the engine and configured to generate a tachometer signal which comprises a pulse sequence;

a speedometer sensor coupled to the drive mechanism and configured to generate a speedometer signal which indicates a ground speed; and

a vehicle control unit configured to receive the tachometer signal and the speedometer signal, and coupled to the electronic ignition system to provide a modified tachometer signal which comprises a modified pulse sequence, wherein the modified pulse sequence is derived by selectively passing and suppressing pulses from the pulse sequence, and wherein the vehicle control unit suppresses pulses when the ground speed exceeds a predetermined ground speed value,

wherein the vehicle control unit includes a memory for logging faults, and wherein the vehicle control unit logs a ground speed fault when the ground speed exceeds the predetermined ground speed value by a predetermined margin, and

wherein the control unit further includes a shock sensor configured to detect excessive accelerative forces, and wherein the vehicle control unit logs a shock fault when the accelerative force exceeds a predetermined force value.

2. The vehicle of claim 1, wherein the vehicle control unit also logs a engine speed fault when an engine speed exceeds a predetermined engine speed value.

3. The vehicle of claim 1, wherein the vehicle control unit includes a communications port coupled to the memory, and wherein the vehicle control unit is configured to transmit the faults logged in the memory upon request.

4. The vehicle of claim 3, wherein the communications port is an infrared communications port.

5. A vehicle control unit which comprises:

a microcontroller configured to receive a speedometer signal indicative of a ground speed, configured to receive a tachometer signal which comprises a pulse sequence, and configured to responsively provide a suppression signal;

an output signal unit configured to receive the tachometer signal and the suppression signal, and configured to provide a modified tachometer signal by passing pulses from the tachometer signal when the suppression signal is de-asserted, and by suppressing pulses from the tachometer signal when the suppression signal is asserted, wherein the microcontroller is configured to assert the suppression signal for a selected number of consecutive pulses when the ground speed exceeds a predetermined ground speed value;

a nonvolatile memory coupled to the microcontroller and configured to store log information, wherein the log information includes fault records, wherein each fault record includes a time of occurrence, a fault type, and a fault value;

a communications port coupled to the microcontroller, wherein the microcontroller is configured to respond to commands received via the communications port, and wherein at least one such command response includes transmitting the log information via the communications port; and

an accelerometer coupled to the microcontroller, and configured to detect peak accelerations experienced by the vehicle control unit.

6. The vehicle control unit of claim 5, wherein the communications port is an infrared communications port.

7. The vehicle control unit of claim 5, wherein the microcontroller is configured to store a ground speed fault record if the ground speed exceeds the predetermined ground speed value by a predetermined margin.

8. The vehicle control unit of claim 7, wherein the microcontroller is configured to store an engine speed fault record if the tachometer signal indicates an engine speed that exceeds a predetermined engine speed value by a predetermined engine speed margin.

9. The vehicle control unit of claim 5, wherein the microcontroller is configured to store an acceleration fault if the peak acceleration exceeds a predetermined acceleration value.

10. A method for increasing vehicle safety, wherein the method comprises:

receiving a tachometer signal which comprises a pulse sequence;

receiving a speedometer signal which indicates a ground speed;

deriving a modified tachometer signal by selectively passing and suppressing pulses from the tachometer signal, wherein the deriving includes;

determining if the ground speed exceeds a predetermined ground speed value;

when the ground speed exceeds the predetermined ground speed value, suppressing a selected number of pulses;

providing the modified tachometer signal to an electronic ignition system; and

compiling a fault record during vehicle operation, wherein the compiling includes;

for predetermined time intervals during vehicle operation;

storing a ground speed fault record if the ground speed has exceeded the predetermined ground speed value by a predetermined margin within the previous time interval;

storing an engine speed fault record if the engine speed has exceeded a predetermined engine speed value by a predetermined engine speed margin within the previous time interval;

measuring a peak acceleration for the previous interval; and

storing an acceleration fault record if the peak acceleration exceeds a predetermined acceleration value.

11. A method for increasing vehicle safety, wherein the method comprises:

receiving a tachometer signal which comprises a pulse sequence;

receiving a speedometer signal which indicates a ground speed;

deriving a modified tachometer signal by selectively passing and suppressing pulses from the tachometer signal, wherein the deriving includes;

determining if the ground speed exceeds a predetermined value;

when the ground speed exceeds the predetermined value, suppressing a selected number of pulses;

providing the modified tachometer signal to an electronic ignition system;

compiling a fault record during vehicle operation, wherein the compiling includes;

for predetermined time intervals during vehicle operation, storing a ground speed fault record if the ground speed has exceeded the predetermined value by a predetermined margin within the previous time interval;

determining if the fault record indicates reckless vehicle operation; and

indicating which vehicle operators should be prohibited from operating vehicles.

12. A computer readable storage medium in which software is stored for performing the method recited in claim.