Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T7/00—Brake-action initiating means
  • B60T7/12—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
  • B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
  • B60W10/18—Conjoint control of vehicle sub-units of different type or different function including control of braking systems
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
  • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
  • B60W30/18—Propelling the vehicle
  • B60W30/1819—Propulsion control with control means using analogue circuits, relays or mechanical links

Definitions

• This invention relates to a device for maintaining a vehicle in a stationary condition.
• a limitation of these mechanisms is that a driver not only must excercise control when driving, but also, in certain conditions, must exercise such control when the driven vehicle is stationary. For example, if the vehicle is arrested on an incline, braking pressure must of course be exerted, either by means of a hand or foot brake. In heavy traffic, repetitive use of these controls may be tiresome.
• a well known feature of such vehicles is their tendency to creep forwards unless braking pressure is applied, even when the vehicle is arrested on level ground.
• 'hill-starts' performed in vehicles having manual transmission require skill in the manipulation of clutch, accelerator and handbrake.
• a primary object of the present invention is to reduce or eliminate the above problem, although as will become apparent from the following description the invention may also be applied to cars having manual gearboxes. Summary of the Invention
• a device for maintaining the vehicle in a stationary condition characterised in that it comprises first means for producing an output signal responsive to the concurrent existence of at least two detected conditions, including the conditions that the vehicle is substantially stationary and there is no effective activation of the accelerating mechanism, and second means responsive to the output signal and adapted to act on the transmission or braking mechanism to maintain the vehicle in a stationary condition.
• the first means, in producing the output signal may additionally be responsive to the absence of the driver's actuation of the braking mechanism.
• the device may include means for detecting the road speed of the vehicle and for providing a signal, indicating that the vehicle is stationary to the first means when the detected road speed is below a predetermined value.
• the detecting means may include a transducer responsive to rotation of a road wheel of the vehicle or rotation of a component of the transmission whose speed bears a one to one relationship with road speed.
• the device may be adapted for use with a vehicle having a speedometer and include a switch controlled by the speedometer to indicate that the vehicle is stationary.
• the second means may include an electromechanical actuator adapted to vary the braking pressure of the braking mechanism.
• the actuator may be adapted to act on the master cylinder.
• the second means may include an electromechanical actuator adapted to selectively prevent rotation of a transmission component.
• the arrangement may be such that the output signal from the first means is produced after a predetermined delay after the required conditions are established.
• the second means may comprises an electromagnetic or hydraulic actuator for exerting pressure on the braking system of the vehicle.
• the said means may comprise means for engaging the transmission of the vehicle to indirectly prevent rotation of the road wheels normally driven thereby.
• this may take the form of an actuator for engaging the 'parking' position pawl normally associated with such transmissions.
• braking systems which, once pressure is applied thereto, cause a pressure-sensitive or brake position sensitive switch to complete a circuit and so to illuminate braking warning lights.
• a signal indicating absence of effective activation of the braking system is conveniently obtained directly from detection of the absence of completion of the circuit. (This second signal operates a self locking bi-stable latch.)
• a micro-switch positioned to detect the rest position of an accelerator pedal of the vehicle is used to provide the aforementioned said third signal indicating absence of pressure applied thereto.
• a micro-switch may also be used, instead of the brake pressure sensitive switch, to indicate absence of effective actuation of the brake pedal.
• the brake indicator lights will automatically be retained illuminated.
• the self locking latch circuit ensures that the actuator remains energized.
• Pressure on the accelerator is therefore required to release the automatic braking mechanism, so breaking the latch circuit causing operation of the actuator, as well as resetting the latch.
• a signal indicating movement of the vehicle may be provided in a number of ways.
• the signal is derived from a transducer arrangement positioned to detect rotation of the transmission or one or more of the road wheels of the vehicle.
• the signal may be provided by the completion of a circuit responsive to the speed detected by the existing speedometer of the vehicle, for example, by detection of the displacement of the speedometer indicator.
• Fig 1 i)-iv) shows schematically accelerator and braking controls of a vehicle embodying the invention and circuitry associated therewith
• Figs 2a, 2b show two possible forms of actuator for controlling movement of a vehicle embodying the invention
• Fig 3 is a schematic diagram of a timing circuit used within the invention.
• braking and accelerator controls of a vehicle are schematically indicated at 10 and 11.
• a speedometer of the vehicle is shown at 12.
• Exertion of braking pressure on the control 10 is indicated by means of the closure of a pressure sensitive switch 13.
• This switch is used to fulfill two purposes, the first being to provide activation of a braking warning light system of the vehicle (not shown) and the second being to provide a signal 'b', when closed, to theNOR gate shown in Fig 1 iv).
• a microswitch 14 is positioned adjacent to the accelerator control 11, for detecting the position thereof. (This switch may be positioned elsewhere within the vehicle on a convenient part of the accelerator linkage).
• the microswitch provides a signal 'c'.
• a signal 'a' is provided by a contact arrangement within the speedometer 12, indicating displacement of the speedometer needle from its rest position, and therefore movement of the vehicle.
• the three signals, a,b and c are supplied to the OR inverter gate shown in Fig 1 iv), the output of which remains passive unless all three signal are absent.
• the circuitry associated with the controls and speedometer provides an active output signal from the inverted OR gate of Fig 1, only when the vehicle is substantially stationery, and no substantial pressure is applied to both the brake and accelerator controls. In other words, once the driven vehicle has been stopped, and no influence thereon is made by the driver, an output signal indicating this condition is given, by virtue of the fact that none of the three signals a, b or c is present.
• this output signal is made to energize an actuator for maintaining the vehicle of the invention in a stopped state.
• a driver need not exert any control over his vehicle once it has been brought to a stop, as this function is automatically accomplished.
• the accelerator or brake
• the 'self-locking' bistable circuitry 3 is disenabled, and the vehicle is free to move again.
• this arrangement may be especially advantageous, but besides these considerations, the safety of a vehicle so equipped is improved in that inadvertent movement such as rolling forwards or backwards into other objects once stopped, is prevented.
• the clutch of the vehicle may be partially engaged by a driver carrying out a hillstart, simultaneous with application of pressure on the accelerator, so in turn automatically releasing the aforementioned mechanism used to maintain the vehicle stationery.
• This arrangement makes easier 'hill-starts', as will be appreciated, as use of a hand brake is unnecessary.
• Figs 2a, 2b two forms of actuator for maintaining the vehicle stationery are shown at 15 and 15 .
• Each is responsive to the active output signal of the inverted OR gate of Fig 1. (Relay or thyristor circuitry, not shown, is provided to enable the low-power elements of Fig 1 to drive the relatively high-power actuators.)
• the actuator designated 15 the vehicle is maintained stationery by means of a plunger 16, which forms the core of an electromagnet 18, exerting pressure when energised, on a suitably adapted vehicle braking system.
• energisation of the electromagnet 19 causes engagement of a lug 20 with the transmission shaft or gears of the vehicle, represented by the cog 21, so preventing rotation in turn of the wheels driven thereby, and thus movement of the vehicle.
• braking pressure is applied by means of an electromagnetically controlled valve interacting with the brake servo-system, so directly regulating, in suitable manner, the brake vacuum pressure.
• an electromagnetic sensor is depicted at 22 for sensing the rate at which teeth on the cog 21 (which for convenience, represents generally the rear transmission of the vehicle) pass thereby.
• Pulses from this sensor are fed to a comparator timing network, shown at 23 in Fig 3.
• a schematic representation of such a train of pluses is shown at 24.
• the frequency and mark/space ratio of the pulses varies, obviously, according to the speed of the vehicle.
• the object of the network is to determine once the rate of pulses falls below, a predetermined threshold or stops altogether, so indicating that the vehicle has, effectively, been stopped.
• the output of the network 'a' becomes inactive, so switching on the actuator 17 once signal "b'and 'c' also become , inactive, as described earlier.
• the signal a may be obtained from existing circuits.
• the braking pressure signal b may be omitted, the actuator signal being derived solely from the speed of the vehicle and the position of the accelerator. In this arrangement, the vehicle is maintained stopped, once stopped, regardless of the position of the brake pedal.
• a switch may be connected into the circuitry for disenabling the facility at the driver's discretion.
• a small delay may be incorporated within the circuit shown in Fig 3, to prevent immediate actuation of the automatic braking system once detection of absence of road speed and or pressure on the controls of a vehicle is detected.
• the road wheels are given an opportunity to rotate, so indicating movement of the vehicle to the actuator system and in turn preventing operation thereof.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Automation & Control Theory (AREA)
• Regulating Braking Force (AREA)

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• 1981
  • 1981-12-18 WO PCT/GB1981/000273 patent/WO1982002176A1/en unknown
  • 1981-12-18 EP EP82900115A patent/EP0067190A1/de not_active Withdrawn

Non-Patent Citations (1)

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