RELEVANT PATENTS
- US Patent
3599052
Aug
10 1971
Automoble Speed Control (Carp, Howard, Slavin and
Leoncio) Assignee: Bendix Corporation
- US patent 3,937,980
February
10, 1976 Printed Wiring
Circuit Guard Ring
- US Patent 4,394,739
July
19 1983 Automatic speed control system for an automotive
vehicle (Suzuki et al) Assignee: Nissan Motor Company Abstract:
Automatic speed control system is provided which
has circuitry responsive to the turning off of the system's restart
switch. This circuitry activates the control upon detection of
a control signal, generated as a function of the difference between the
actual vehicle speed and the set speed, when the restart
switch switches off. In the system according to the present invention,
the vehicle is effectively prevented from unexpected acceleration
caused by the misoperation of the restart switch or damage thereof.
- US Patent 4,434,469
February
28th 1984 Automatic Speed Control for an automotive
vehicle (Suzuki, et al.) Assignee: Nissan Motor Company, Abstract:
An
automatic speed control system for an automotive vehicle for
controlling the vehicle driving speed at a pre-set constant speed
comprising a setting device for pre-setting as desired vehicle speed ,
a control for controlling the throttle valve position or the carburetor
in order to keep the vehicle speed at the pre-set value, and an
accelerator switch for resetting the pre-set value and renewing the
pre-set value in the control system. A safety means is provided in the
control system and is cooperative with a brake switch which is turned
on while the brake is applied. The safety means becomes operative in
response to turning on of the brake switch while the accelerator switch
is in an ON condition.
- US patent 4,472,777
September
18, 1984 Engine Control Apparatus for Vehicle Speed
(Youngblood, Ralph A. ) Assignee: Ford Motor Company
- US Patent 4549266
October
22 1985 Vehicle Speed Control (Schneider, Jack H.;
Huber, Gary D.) Assignee Ford Motor Company. Abstract:
An automotive speed control system uses logic
activated switches on both sides of solenoids controlling vent and
vacuum valves. A vacuum solenoid is activated upon the simultaneous
occurrence of an activation of a vent valve solenoid, an activation of
the speed control system, and a determination that solenoid current is
below a desired magnitude.
- US Patent 5,216,609
August
9 1991 Vehicle speed control system with multiplex switch
decoding. (Oo; Kah S. ) Asignee: Ford Motor Company.
Abstract : A speed control system having an
operator actuable switch assembly providing a single multiplexed
output. The switch output is scaled with respect to
the switch reference voltage to concel any effect of noise or battery
voltage variation. Decoding of the scaled output provides the speed
control system with the appropriate operator actuable command
after all switches of the switch assembly are concurrently detected in
a neutral position.
- Further searching on automobile speed control
patents can be carried out free of charge at the US Patent and
Trademark Office: http://patft.uspto.gov/
PAPERS AND REPORTS
- Anderson, A. F.
Reliability in
Electromagnetic Systems: The role of electrical contact resistance in
maintaining automobile speed control system integrity IET Colloquium on Reliability in
Electromagnetic Systems, Paris, May 24-24 May 2007. Abstract: Electromagnetic
systems depend upon the integrity of electrical connections. An
intermittent speed sensor connection is shown to generate a false speed
signal that may allow an automobile speed control system to engage at
low speed and cause a sudden acceleration. Preventive measures are
discussed. The current approach to controlling uncommanded sudden
accelerations seems to rely upon the driver braking against full engine
power to bring the vehicle to a halt. More effective and safer control
would be achieved by cutting off the fuel supply the moment that an
uncommanded wide open throttle condition was detected, thereby
preventing the sudden acceleration. PDF
Copies obtainable from the author
by e-mail at: <antony.anderson@onyxnet.co.uk>
IET webcast: http://tv.theiet.org/technology/electronics/1051.cfm
"Electronic
sub-assemblies (ESAs) are being increasingly used where they could
affect vehicle safety risks, including every aspect of drivetrain
control, and many aspects of body control, including lighting,
displays, indicators and mirrors. Anything that could affect the direct
control of a vehicle, or could confuse other road users, is of concern.
Indeed, there are many current developments that are
safety-related, such as automatic parking, intelligent cruise control,
automatic lane following, vision-aids, and vehicle-to-vehicle telemetry
(enables vehicles to start braking when traffic ahead slows, even when
hidden around bends or in fog) that would not be possible without
advanced electronics and its software. The problem is that all
ESAs can suffer from errors, malfunctions and even permanent damage due
to electromagnetic interference (EMI). Further, the EM environment is
continually worsening due to the increasing use of electronic
technologies in all areas of society, especially switch-mode power
conversion and wireless communications. Another
problem is that all ESAs rely on semiconductors, either as discrete or
integrated circuits (ICs), and the continuing shrinkage in their
internal silicon features and reductions in operating voltages are
making them more susceptible to EMI. So, for several reasons, the
importance of EMI to the safety of vehicular transport is increasing.
Standards
in all industry sectors, including the automotive industry, generally
deal with EMI-related safety issues very poorly, if they even cover it
at all. The few that attempt to address these issues simply
require the application of traditional EMC immunity tests that can
never be sufficient for ensuring tolerable safety risks over the entire
lifecycle, for reasons which we’ll described later. Over
the last ten years or so, there have been developments in applying risk
management techniques to EMC to correctly address EMI-related safety
issues. Specifically, there is IEC TS 61000-1-2 (which is
effectively the missing EMC Annex of the basic functional safety
standard IEC 61508, and the IET’s new guide on “EMC for Functional
Safety”. Excellent paper that lays the groundwork for a functional
safety based approach to automobile electronic design manufacture and
testing. For further useful EMC articles and links see http://www.cherryclough.com/Pages/Links.htm
- Gunnerhed,
M.
:
Risk Assessment of Cruise Control (Audi)
FOA
Report $ 30010 -3. 3 May 1988 ISSN 0281-9937 Swedish Defence
Research Establishment, Department of Information Technology. Abstract:
With the wider use of electronic devices and systems in cars, the
safety implications of electronic systems have become evident.
According to reports from the USA, numerous lethal accidents have
occurred due to sudden acceleration. Accidents in Sweden have also been
reported. At the request of the Swedish Road Safety Office, the Swedish
Defence Research Establishment has carried out a risk assessment of a
cruise control system in order to establish its safety performance.
This system, made by HELLA, is an optional device in many common cars.
It comprises electronic as well as mechanical and pneumatic subsystems.
By means of reliability analysis methods such as Fault Tree Analysis
and Fault Modes and Effects
Analysis, some single-point-fault modes are disclosed. The risk
assessment, verified in tests, shows that a single fault such
as a bad solder joint causes sudden acceleration. This means that the
alleged events are possible. This disclosed single-point-fault mode
establishes an upper limit for the safety of this cruise control.
[System Designation : HELLA GR Steuergeraet 12 5GA 003 828-00].
- Kimseng,
K.
, Hoit, M., Pecht, N. : Physics of
Failure of a Cruise Control Module Microelectronics
Reliability Vol 39, pp. 1423-1444 February 1999.
Over a five year period owners of a
particular cruise control had complained that it did not properly
operate. Typical intermittent faults complained of : not engaging upon
command; unexpected acceleration overshooting the desired set speed.
More than 96% of the reported failed modules returned to the company
passed bench tests. The paper presents a physics-of-failure process to
identify, induce and analyze failure mechanisms causing intermittent
failures. Explains why the manufacturer's tests were neither
representative of automotive environments, nor were conducted in
a way that would have enabled actual failures to be assessed. [A
very important paper that explains and manages to reproduce
intermittent open and short circuits on suspect cruise control PCBs.
Paper does not however consider the control system response
implications of particular open or short circuits.]
- Electronic
Throttle
Control A Dependability Case
Study Hans Mauser (Siemens AG, ZT PP 2) and
Erwin Thurner (Siemens AG, ICN WN ES HW 42).
The paper examines reliability issues connected
with an electronic throttle control, in which the mechanical link
between the accelerator pedal and the throttle is replaced by an
electronic link. It scrutinises the safety and availability of a
variety of electronic control architectures and their capability to
ensure that under fault conditions built-in system redundancy will
either maintain system performance, or ensure that it degrades
gracefully to allow safe limp home or safety stop. It considers
that about 1% of single faults may cause a runaway condition. The
faults that might lead to runaway include: faulty torque requests
induced by faults in various car components (gear switch signals,
deceleration slip control, faulty pedal reference signal etc.), faults
in analogue to digital converters, faults in the torque computing
process, processor faults. The authors conclude that a dual
processor system is required with each
processor checking the other processor, as a minimum, to ensure an
adequate degree of safety and that the best solution would be a
full dual electronic system, with each system checking the other, and
with one processor checking the process calculations. [Although cruise
control - i.e. an outer speed control loop - is not specifically
mentioned, a fault in the cruise control loop would, in their
terminology, generate a faulty torque request. Possible cruise control
faults would therefore seem to be covered by their approach.]
EMC
and
Functional Safety in Road Transport [Annex to IEE Guidance
Document on EMC and Functional Safety]. Lists
21
electronic systems that may be present in the modern automobile,
including cruise control, some of which have the potential to
endanger the safety of the vehicle occupants or other road users should
an error or a mis-operation occur. It categorises the EMC phenomena
that need to be considered under six headings (broadband radiated
emissions, narrow band radiated emissions, conducted transient
emissions, conducted transient immunity, radiated immunity and
electrostatic discharge) and summarises the standards on each. It
summarises the Automotive EMC Directive and offers a critique from a
safety point of view. It concludes with a summary of known incidents
connected, or claimed to be connected, with EMC.
- The
experience of the Anticipatory Failure Determination (AFD) method
applied to an Engine Concern Vladimir
Proseanic
(Ideation Int.) Dmitry Tananko (Ford Motor Co.) Svetlana
Visnepolschi (Ideation Int.) The paper
discusses the results of the AFD application to solving a
Hitching/Ringing concern on an Engine. The AFD approach has been used by a joint Task Force team to identify the
root
cause of this Hitching/Ringing phenomena.The problem is related to slow
oscillation of the whole powertrain of the vehicle under steady pedal
position (Ringing) or cruise control condition
(Hitching). [First presented at the Altshuller Institute TRIZCON2000,
May 1, 2000].
- NASA RP 1374 July
1995: Report
on
Electronic
Systems Failures and Anomalies Attributed to Electromagnetic
Interference "This report is to
acquaint the reader with spacecraft electronic systems failures and
anomalies caused by electromagnetic interference (EMI), show the
importance of electromagnetic compatibility (EMC) activities in
conjunction with space flight programs, and provide an investigation
into the history of some well-known EMI system failures and anomalies
in military and commercial electronic systems... The inclusion of
nonspace systems also helps to illustrate that evolving electronic
systems are increasingly sensitive to EMI and NASA personnel must
continue to be diligent in the pursuite of EMC on space flight systems."
- Defence Standard 59-41 (Part 6) Issue
1 26 August 1994. Electromagnetic Compatibility Part 6 : Code of
Practice for Military Vehicles Installation Guidelines. [UK
Ministry of Defence] Guidelines for the electromagnetic compatibility
of military vehicles in terms of their design and construction and in
the design and installation of electrical and electronic equipment and
systems within them. http://www.dstan.mod.uk/data/59/041/06000100.pdf
- Preempting aircraft wiring failures
will have a direct impact in making commercial and military aircraft safer. AFRL's Information Directorate,
Information Technology Division, Dynamic Command and Control Branch,Rome NY. Wire cable chafing and connector corrosion are well
understood and age-related problems, which contribute greatly toaircraft wiring failure. They are also suspect in several
military and commercial aircraft incidents and accidents. The Information Directorate developed several innovative
techniques to detect these problems before they cause system failures.1,2,3 Both techniques discussed in this article
received patents in the summer of 2001 (Patent Nos. 6,265,880 and
6,275,050).http://www.afrlhorizons.com/Briefs/Mar02/IF0011.html
- Food and Drug
Administration (FDA)
Concerned with Electromagnetic Interference (EMI) Problems : Talk
Papers from the Food and Drug Administration The FDA, as the primary agency overseeing the safety of
electronic medical devices, has recently increased its interest in
reports of electromagnetic interference with the function of electronic
medical devices and motorized aids like wheelchairs and scooters. For
example, a stray signal from a cellular phone, CB radio, or similar
piece of transmission equipment could cause a person in a powered wheel
chair waiting for a red traffic light to move uncontrollably into the
intersection. These concerns were addressed in two Talk Papers released
on August 8 and August 26, 1994:
T94-35,
August 8, 1994 ELECTROMAGNETIC INTERFERENCE
WITH MEDICAL DEVICES
T94-39, August 26,
1994 ELECTROMAGNETIC INTERFERENCE WITH POWERED
WHEELCHAIRS
http://infoventures.com/emf/federal/fda/emi-fda.html
- Keeping Medical Devices Safe from
Electromagnetic Interference by Rebecca D. Williams
May 1995 FDA Consumer Reports how a
man in a powered wheelchair was seriously injured when his chair rode
off a cliff at high speed. He was several miles from a radio tower and
three blocks from a busy road, where mobile radios were likely in use.
http://www.fda.gov/fdac/reprints/emi.html
ELECTRICAL
CONTACTS
- Electrical Contacts - background
references:
- Braunovic,
Milenko; Konchits, Valery V.; Myshkin, Nikolai K.: Electrical Contacts
- Fundamentals, Applications and Technology CRC Press 2007 ISBN
-13:978-1-57444-727-9, ISBN-10: 1-57444-727-0
- Slade, Paul G.;Editor. Electrical
Contacts - Principles and Applications Marcel Dekker, Inc 1999 ISBN
0-8247-1934-4
- Holm, Ragnar : Electrical Contacts
-Hugo Gebers Foerlag Stockholm 1946 Fundamental study of the
theory and practice of electrical contacts
- Llewellyn-Jones, F. : "The Physics
of Electrical Contacts" Oxford 1957, which refers to the work of
Fairweather:
- Fairweather, A. Effects of
corrosion on a closed metallic contact and Microphonic noise
J. Inst. Electrical Engineers (1945) Vol
92, 301. Proc Inst Elect Engrs (1953) Vol 100 (1) 154.
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