DE102017001064B4 - AAS, anti-aquaplaning system - Google Patents

Abstract

Anti-aquaplaning system (AAS), which is automatically activated by rain and can be switched on and off manually on a wet road surface, even without rain, the AAS having a system control which is based on parameters of the vehicle data, in particular tire parameters, tire weight , tread depth, vehicle weight, length, width and height, is programmed and calculated from the critical values of the water suspension pressure, the buoyancy and/or the static friction on the 4 tires in the context of the current sensor data such as water suspension pressure, crosswind pressure and/or tire pressure on the vehicle, with the calculated data are displayed to the driver at any time on the on-board computer and when critical values are reached, the speed is automatically adjusted accordingly without manual intervention by the driver, with the tire sensors measuring the water inflation pressure at 2 or more points on the inside of the tire profile at all 4 wheels are integrated in the tire.

Description

AAS, anti-aquaplaning system

Regardless of the car brand, class and drive (petrol, diesel, gas, electric), aquaplaning is and will continue to be a risk factor in the future. Every car driver has already experienced that rain, wind and inadequate speed, as well as low tire tread depth, depending on the tire diameter and tire width, can result in water bulging (aquaplaning) on the tire.

State of the art

The German patent application DE 10 2011 113 908 A1 discloses a method for longitudinal control of a vehicle in which there is a sensor system with which a layer thickness of a water layer on the roadway can be determined, an evaluation means is present with which a parameter can be determined based on the determined layer thickness and a current speed of the vehicle, which parameter specifies a measure of a risk of aquaplaning, which causes a control means of the longitudinal control system to control the setpoint speed.

The Swiss patent application CH 708 955 A2 discloses an apparatus for measuring the tire operating parameters of a stationary and moving vehicle. The device includes sensors built into the tires to measure tread depth and transponder chips to measure tire pressure and temperature. Each tire is fitted with a transponder chip. A near-field module with an antenna is installed in each wheel housing. The data is transmitted using transponder technology, which allows near-field and far-field interrogation. The data is collected and pre-evaluated in vehicle modules. The data is sent to the central vehicle computer for further use via a CAN bus interface.

The US patent application US 2014 / 0 166 168 A1 discloses a stand alone pluggable wear detection system comprising at least one wearable sensor, a stand alone power supply and a radio remote communication facility. During operation, the sensor element changes at least one electromagnetically measurable physical parameter when the tread element wears radially inwards. The system provides a complete treadwear system that includes the signal and data processing algorithm, buffering, and decision-making routines to remotely provide the driver or vehicle owner with the current tire wear status, the match between tire type and vehicle season, and a real-time estimate of tire life remaining.

Progress through AAS

The aim of AAS is safe steering of the vehicle on wet roads and the prevention of aquaplaning.

AAS can detect the problem of water bloating on the tires at an early stage and prevent the vehicle from being uncontrolled (aquaplaning).

While driving, AAS measures the pressure of the amount of water on the tires, the tire pressure, the side wind and, depending on the speed driven, calculates the critical value of the static friction on the tires.

AAS can help to avoid damage to people and machines through proactive action by the driver and to prevent consequential damage from occurring in the first place.

AAS shows the driver the critical condition via the on-board computer in good time before a possible aquaplaning. The system is switched on automatically when it rains or can be switched on manually when the road surface is wet (without rain). Accidents caused by aquaplaning can be prevented by automatically adjusting the speed. The critical tire tread depth is continuously displayed to the driver.

The Control Panel of AAS

Drawings: Figure 2, 2a

The AAS control panel is the brain of the vehicle. It uses algorithms to calculate the water pressure/buoyancy/static friction on the tire, which can trigger aquaplaning at low values. The amount of rain falling on the rain sensor, the water pressure on the tire sensor suspension pressure, the tire pressure on the tire pressure sensors, the tire tread depth on the tire sensors, the crosswind sensors and depending on the speed, as well as the weight and the condition of the tires are parameters for calculating the critical suspension pressure/buoyancy/static friction.

If the vehicle is put into operation on a wet wet road surface and without rain, the vehicle driver can switch the AAS on and off manually. AAS switches off automatically when the road surface is dry.

The shallower the profile depth, the wider the tire and the narrower the profiles are arranged on the tire tread, the more critical the water flotation pressure/buoyancy/friction on the tire becomes. When a critical level of inflation pressure/lift/friction is reached, AAS automatically initiates a reduction in speed (slightly delayed braking). The vehicle's specific tire data are programmed as parameters into the system control (mechanic or factory).

If a critical value of the tire tread depth is reached, the vehicle driver is alerted to change the tyre. (traffic safety)

restriction:

4 identical tires (manufacturer) must always be used.

A notice:

A component -tire pressure sensor- is not intended for AAS, as this functionality is already used in most vehicles and can be integrated by AAS.

Option:

The components - tire pressure sensors - and tire tread depth sensors can be switched on permanently if required and displayed on the on-board computer.

Use case description: Control panel

Surname control panel short description The system control is activated by rain falling on the front rain sensor or by manual activation by the driver and receives the data from the components "crosswind sensor", "tire sensor inflation pressure", "tire sensor tread depth", "tire pressure sensor" and uses this information to calculate the critical inflation pressure / lift / friction on the tire using an algorithm. The empty weight of the vehicle is used to calculate the lift/friction. Sensor data from all 4 wheels is used to calculate lift/friction. actors Driver, rain sensor, crosswind sensor, tire tread depth sensor, tire pressure sensor, on-board computer trigger Rainwater at the rain sensor Extension: On wet roads and without rain, the driver manually activates the AAS at the beginning of the journey. precondition The vehicle is moving and the rain sensor is active Result The critical water flotation pressure / buoyancy, crosswind pressure, tread depth and tire pressure are determined and the critical static friction on the tire is calculated. postcondition The calculated data is displayed on the on-board computer and a speed reduction is automatically initiated if the values are critical. Essential process 1. The vehicle is in motion 2. It's raining Extension: The vehicle is set in motion on a wet road surface and without rain 2a. The driver activates AAS manually 3. The rain sensor activates the AAS system control 4. The AAS Control Panel activates the other components of AAS 5. The components of AAS send data to the AAS system control (all 4 wheels) 6. The AAS system control uses an algorithm to calculate the critical water suspension pressure / buoyancy / static friction on the tire through pre-programmed parameters and the data of the components of AAS 7. The calculated data and values are displayed on the on-board computer 8. After reaching critical values like: Floating pressure / static friction on the tires, the speed of the vehicle can no longer be increased. If the tread depth on the tires is critical, the vehicle must have its tires changed within a specified period. If the tire pressure is critical, the vehicle can only be moved at a reduced speed

Syntax and semantics of calculations for aquaplaning

syntax semantics rk = f (v _dyn , V, d, b, F, ...) N, m ² , √, cm, N, Calculation of the coefficient of friction Definition (wiki) The coefficient of friction, also known as the coefficient of friction, is a dimensionless measure of the frictional force in relation to the contact pressure between two bodies. Here the contact pressure of the tire tread on the road rk = √v _dvn .Vb/F Formula: Coefficient of Friction rk = coefficient of friction (10 - 3) = √ v _dvn . V b / F v _dyn = dynamic viscosity for water v = vehicle speed b = tire width F = weight force per tire N/ ^m2 = Newtons per ^m2 m ² = square meter cm = centimetres N = Newtons Km/h = kilometers per hour . = multiplication sign / = division sign (divided by...) Wd,w,cp,p,v,kg/m ² , Nm ² , A, p _stau , Calculating the wind pressure Definition wind pressure (wiki) Force or pressure on a vertical area of 1 m2 with cp = 1 at different wind strength values. Wd = cp. p/2. v ² Formula: wind pressure Wd = wind pressure (Kg/ms) cp = pressure coefficient (without dimensions) p = density of air (at 0 degrees at sea level = 1.293 kg/m ³ , at 20 degrees = 1.204 kg/ ^m3 v = wind speed m/s Kg/ms = kilograms per meter per second . = multiplication sign / = division sign (divided by...) v ² = wind speed squared m ² = cubic meters w = A.Wd Formula: Wind load (Kgm/s ² w = wind load A = reference area in m ² Wd = wind pressure (Kg/ms) m ² = square meter m/s = meters per second Pstau = p/2. ^v2 Formula: pstau w = cp. A Pstau Formula: wind load

The rain sensor from AAS

drawings, figure 3

The AAS rain sensor on the front of the vehicle activates the AAS system control when it begins to rain. The amount of rain that falls can also control the wiper system.

A notice:

The wiper system on the vehicle can currently be switched on and off manually. However, the AAS rain sensor must remain independent of manual operation. It must activate automatically when it rains and only when the vehicle is moving. Therefore, if water falls artificially on the sensor, such as in the car wash, the AAS will not activate.

If a vehicle is operated on a wet road but no rain is falling, the driver can manually turn the AAS on and off.

Use case description: Rain sensor

Surname Activation of AAS system control by the rain sensor front short description When it begins to rain while driving, the raindrops hit the rain sensor. This activates the AAS control panel, which then activates all AAS components. The rain sensor measures the amount of rain falling and activates the quantitative control of the wiper system actors Driver, Rain Sensor, Rainwater, Control Panel trigger Incoming rain on the rain sensor precondition The vehicle is in motion Result The rain sensor has activated the AAS system control and the wiper system on the vehicle postcondition The rain sensor switches off automatically when it stops raining Essential process 1 . It's raining 2. The rainwater falls on the sensor 3. The rain sensor is activated 4. The rain sensor activates the AAS system control 5. The AAS system control activates all AAS components (sensors) 6. The rain sensor can be deactivated when it no longer falls. 7. The other AAS components remain active until the roadway can be driven on without risk (parameters such as low suspension pressure). Note : For this purpose, a calculated value of the static friction, from which there is no longer any risk of aquaplaning, must be determined

The crosswind sensors from AAS

drawings, figure 4

The side wind sensors, or the manipulated variables used for this purpose, measure the wind pressure on both sides of the vehicle. The measured values are used by the AAS system control as parameters for the calculation of the critical road adhesion / static friction in wind and rain. Other parameters such as the weight of the vehicle, the condition of the tires (height, width, tread depth) and the height of the vehicle (reference area) are relevant. These parameters from the tire manufacturer and the car industry are previously programmed into the AAS control panel.

Use case description: cross wind sensors

Surname Measure side wind pressure on the vehicle (left and right). short description The side wind sensor measures the current wind speed and the associated lateral pressure on the moving vehicle. The measured data is transmitted to the AAS system control for calculation of the critical values. actors Driver, crosswind sensors (2x), control panel, on-board computer trigger Wind pressure on the side of the vehicle while driving precondition The wind pressure sensor is activated Result The wind pressure values on the vehicle sides (left and right) are measured and transmitted to the AAS system control postcondition The measured values are displayed on the on-board computer Essential process 1. The vehicle is in motion 2. The wind pressure values are measured 3. The wind pressure values are transmitted to the AAS system control to calculate the critical values during driving 4. The readings are displayed on the on-board computer

Tire tread depth sensors

Drawings, Figure 5, 5a

The tire tread depth sensor continuously measures the distance of the tire tread from the tread (rolling side) of the tire to the inside of the tire. The lower the tire profile and the more structured the arrangement of the profiles on the tire, the higher the risk of critical water flotation pressure / buoyancy on the tire. In addition, there are statutory minimum distances from which it is no longer permitted to steer the vehicle and non-observance can lead to accidents.

A wearable measuring pin with sensor is permanently integrated in 2 or more tire treads. The abrasion of the tire material goes hand in hand with the abrasion of the integrated measuring pin and thus continuously indicates the current tread depth. The AAS system control forwards these values to the on-board computer in the form of capacitive or ohmic changes. The driver is thus able to have a visual overview of his tire profile.

A notice:

A critical tread depth (specified by the authorities...) does not always have to be reached on all 4 tires at the same time. However, if a critical value is reached on just one tire, it is advisable to replace all 4 tires at the same time.

Use case description: Tire tread depth sensors

Surname Measure the tread depth on the tire short description The tire tread depth sensors continuously measure the distance between the tire tread, which is in direct contact with the road, and the tire tread substrate. A wearable metal pin recognizes the reduction of the tire profile. He measures this in the customary country unit. actors Driver, tire depth sensor, control panel, trip computer trigger The vehicle is in operation precondition The critical tread depth is programmed as a parameter in the AAS control panel Result The tread depth is measured and recorded by the AAS system control and displayed on the on-board computer postcondition If the tread depth is critical, a tire change must take place Essential process 1. The vehicle is in motion 2. The tread depth sensor continuously measures the tire tread depth and forwards it to the AAS system control 3. The system control transmits the measured values to the on-board computer 4. The on-board computer visually displays the tread depth values

The sensors for the water suspension pressure on the tire

drawings, figure 6

The tire inflation pressure sensor continuously measures the current water inflation pressure / buoyancy at 2 or more points on the inside of the tire profile and forwards these values to the AAS system control. The closer the tire treads are arranged to each other and the lower the tread depth, the higher the water pressure / buoyancy on the tire, which can lead to aquaplaning when a critical value (static friction) is reached. The pressure values measured on the tire are the basis for calculating the critical inflation pressure / lift / friction loss. The AAS system control calculates the friction loss (buoyancy) on the rolling tires depending on speed, side wind, tire tread depth, tire condition (summer or winter tires, all tire parameters), vehicle weight, vehicle width, vehicle height, vehicle length.

Use case description: tire sensor water suspension pressure

Surname Measure water suspension pressure / buoyancy short description When driving in the rain or on a wet road, the tire sensor measures the surface pressure / buoyancy of the water accumulated in the tire profile, which cannot be discharged to the outside. (tyre condition). These values are transmitted to the AAS system control. actors Driver, tire inflation pressure sensor, control panel, trip computer trigger From the front rain sensor or manual activation of the AAS system control precondition Rain or wet road Result The water suspension pressure values / buoyancy are measured and transmitted to the AAS control panel for calculation postcondition Display of the critical values on the on-board computer Essential process 1. The vehicle is in motion 2. It is raining or the road is wet 3. Rainwater accumulates in the tire tread gaps 4. The dynamic pressure is detected by the sensor 5. The sensor transmits the pressure values to the AAS system control for calculation of the critical friction value 6. A risk-free speed of the vehicle is automatically initiated when the tires reach critical friction values

The onboard computer display from AAS

drawings, figure 7

The on-board computer constantly shows the vehicle driver the values calculated by the AAS system control and the other measured values of the driving operation. These are water flotation pressure/buoyancy/stiction, tire tread depth, crosswind and tire pressure from non-critical to critical.

Use case description: On-board computer display

Surname On-board computer display of calculated values while driving short description The on-board computer visually shows the driver all values of the water inflation pressure on the tires, the tire tread depth, the cross wind pressure and the tire pressure actors Driver, AAS control panel, trip computer trigger The vehicle is moving on a wet road precondition AAS Control Panel is enabled Result The values of water suspension pressure, tire tread depth, side wind pressure and tire pressure of the moving vehicle are displayed postcondition The measured data are deleted after deactivation of AAS Essential process 1. The system control transmits the data specific to the display to the on-board computer 2. The on-board computer visually displays relevant data to the driver 3. The indicator goes off when AAS is deactivated

Claims (9)

Anti-aquaplaning system (AAS), which is automatically activated by rain and can be switched on and off manually on a wet road surface, even without rain, the AAS having a system control which is programmed based on parameters of the vehicle data, in particular tire parameters, tire weight, tread depth, vehicle weight, length, width and height, and from the critical values of the water pressure, the buoyancy and/or the static friction on the 4 tires in the context of the current sensor data such as water pressure, Cross wind pressure and/or tire pressure are calculated on the vehicle, with the calculated data being displayed to the driver at all times on the on-board computer and when critical values are reached, the speed is automatically adjusted accordingly without manual intervention by the driver, with the tire sensors for measuring the water pressure at 2 or more points on the inside of the tire profile on all 4 wheels integrated in the tire. Anti-aquaplaning system after claim 1 , which can be used for all vehicle types and vehicle sizes. Anti-aquaplaning system after claim 1 , which can be used for all tire types and tire sizes. Anti-aquaplaning system after claim 1 , which automatically and proactively reacts to critical values. Anti-aquaplaning system after claim 1 , which is equipped with a tire depth sensor on all 4 tires, in particular in the form of an abrasive metal pin, and can also be switched on permanently. Anti-aquaplaning system after claim 1 , in which wind pressure sensors react to the side wind pressure on the vehicle and are integrated on the side surfaces of the vehicle. Anti-aquaplaning system after claim 1 , which automatically adjusts the speed of the vehicle when a critical suspension pressure is reached, in particular a critical static friction on the road surface. Anti-aquaplaning system after claim 1 , in which an on-board computer visually displays the inflation pressure, crosswind pressure, tire pressure and tire tread depth values to the driver at all times while driving. Anti-aquaplaning system after claim 1 , in which a rain sensor takes over the activation of the AAS components and can also function as a normal wipe-wash sensor.

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