Method and system for preventing rear end collision of vehicles

• US 20050171681A1
• Filed: 02/18/2005
• Published: 08/04/2005
• Est. Priority Date: 08/19/2002
• Status: Abandoned Application

• Current Assignee: Liu Yang, Tianshu Yang
• Original Assignee: Liu Yang, Tianshu Yang
• Inventors: Yang, Tianshu, Yang, Liu
• Application Number:
  US11/062,085
• Publication Number:
  US 20050171681A1
• Time in Patent Office: Days
• US Class Current: 701/116
• CPC Class Codes: B60Q 1/44 for indicating braking action or preparation for braking, e.g. by detection of the foot approaching the brake pedal
• CPC Class Codes: B60Q 1/535 to prevent rear-end collisions, e.g. by indicating safety distance at the rear of the vehicle
• CPC Class Codes: B60Q 5/006 indicating risk of collision between vehicles or with pedestrians
• CPC Class Codes: B60W 2050/0075 Automatic parameter input, automatic initialising or calibrating means
• CPC Class Codes: B60W 2556/65 Data transmitted between vehicles
• CPC Class Codes: B60W 30/08 Active safety systems predicting or avoiding probable or impending collision or attempting to minimise its consequences
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: B60W 50/14 Means for informing the driver, warning the driver or prompting a driver intervention
• CPC Class Codes: F02D 2200/0404 Throttle position
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• CPC Class Codes: F02D 41/045 Detection of accelerating or decelerating state detection thereof in general G01P
• CPC Class Codes: F02D 41/12 for deceleration F02D41/0005, F02D41/107 take precedence

Abstract

A kind of method and system for preventing rear end collision of vehicles are intended to apply to the vehicles equipped with the electric fuel injection system. By using a fuel-decreasing pre-warning electric control unit standing for PW-ECU, the throttle value D of the engine can be obtained through sampling from the throttle sensor 1 of the electric fuel injection system in real time. Do time differential operation to the throttle value D to get the throttle speed value R_t, then comparing the throttle speed value R_t with a preset fuel-decreasing pre-warning value R_p. If R_t equal to or exceed the preset value R_p when the engine decreases the fuel, the pre-warning devices 7 driven by PW-ECU will send out the pre-warning signals to the following vehicles. Therefore we can realize preventing rear end collision of the vehicles by the fuel-decreasing pre-warning method. At same time we provide a system for preventing rear end collision of the vehicles by the fuel-decreasing pre-warning method.

Claims

1. A method for preventing rear end collision of vehicles, when implementing this method the hardware system of needs should include at least four parts:

(1) The throttle sensor 1 of the electric fuel injection system;

(2) The fuel-decreasing pre-warning electric control unit 22 concerned with the throttle sensor 1;

(3) The electric switch 6 installed between the positive electrode of power supply and the pre-warning devices 7 and controlled by the fuel-decreasing pre-warning electric control unit 22 named as PW-ECU 22;

(4) The pre-warning devices 7 controlled by the electric switch 6;

Under the controlling of PW-ECU 22, the following operations should be executed in the hardware system for implementing this method for preventing rear end collision of vehicles;

a. Sampling from the throttle sensor of the electric fuel injection system and then get the throttle value D;

b. Do the time differentiation operation to the throttle value D and then get the throttle speed R_t;

c. Comparing the throttle speed value R_t with the preset value R_p;

when the comparative result can meet the pre-warning control conditions, we can get the pre-warning control signal;

d. The pre-warning control signal will control the electric switches to turn on and then the pre-warning devices will send out the pre-warning signals to the following vehicle.

2. The method for preventing rear end collision of vehicles as in claim 1, the pre-warning control conditions can be the following:

If R_t≦

R_p, the pre-warning control signal can be generated,
If R_t>

R_p, the pre-warning control signal can not be generated.

3. The method for preventing rear end collision of vehicles as in claim 1, in which the fuel-decreasing pre-warning programs installed into the digital computer of the fuel-decreasing pre-warning electric control unit is used for executing the fuel-decreasing pre-warning operations listed from (a) to (d).

4. The method for preventing rear end collision of vehicles as in claim 3, the fuel-decreasing pre-warning programs can be “

fixed pre-warning time length”

style;

And through the following operations by the microcomputer 19 the fuel-decreasing pre-warning target can be achieved;

S100;

Power on and initializing the registers;

S102;

Storing the time value into the register T_t;

S104;

Calculating the time step length

Δ

t=T_t−

T_o;

S106;

Inquiring the pre-warning time register L_t;

If L_t>

0, program will direct skip to S156;


If L_t≦

0, program skip to S110;

S110;

Sampling from the throttle sensor and then the current throttle value D will be stored into the throttle register D<sub>t+Δ

t</sub>;

S112;

Calculating the difference of the two throttle sampling values,

Δ

D_t=D<sub>t+Δ

t</sub>−

D_t;

S114;

Calculating the throttle speed R_t,

R_t=Δ

D_t/Δ

t;

S130;

Comparing the throttle speed R_t with the preset value R_p,

If R_t≦

R_p, that means the vehicle is on the fuel-decreasing process and the program skip to S132;


If R_t>

R_p, that means the emergency fuel-decreasing condition is came out and the program skip to S139;

S132;

Read the preset pre-warning time t_p into the pre-warning time register L_t, set the L_t=t_p, and then the program skip to S152;

S139;

Set L_t=0, and then the program skip to S154;

S152;

The computer sends the pre-warning instructions and then the instruction will control the electric switch turn on and then the brake lights will lighting and finally the program skip to S156;

S154;

The computer will send out the not pre-warning instructions and the electric switch will turn off and the brake lights will go out and finally the program skip to S160;

S156;

Calculating remainder time of the pre-warning,

L_t=L_t−

Δ

t, program skip to S160;

S160;

The current throttle sampling value D<sub>t+Δ

t</sub> will be transferred into the register D_t, program skip to S162;

S162;

The current time value T_t should be transferred into the register T_o, program skip to S102.

5. The method for preventing rear end collision of vehicles as in claim 3, the fuel-decreasing pre-warning programs can be “

stepping pre-warning time length”

style;

And through the following operations, the fuel-decreasing pre-warning target can be achieved;

S100;

Power on and initializing the registers;

S102;

Storing the current time value into the register T_t;

S104;

Calculating the time step length

Δ

t=T_t−

T_o;

S110;

Sampling from the throttle sensor and then the current throttle value D will be stored into the throttle register D<sub>t+Δ

t</sub>;

S112;

Calculating the differences of the two throttle sampling values

Δ

D_t=D<sub>t+Δ

t</sub>−

D_t;

S114;

Calculating the throttle speed

R_t=Δ

D_t/Δ

t;

S130;

Comparing R_t with the preset value R_p and then analyze the result;

If R_t≦

R_p program skip to S132;


If R_t>

R_p program skip to S138;

S132;

Set the pre-warning time register L_t=t_p, and then the program skip to S152;

S138;

Inquire the idle switch status IDL,

If IDL=0, program skip to S139;


If IDL=1, program skip to S150;

S139;

Set the pre-warning time register L_t=0 and then the program skip to S154;

S150;

Inquire the pre-warning time register L_t,

If L_t>

0, program skip to S152;

If L_t≦

0, program skip to S154;

S152;

The computer will send the pre-warning instruction and the pre-warning devices will send the pre-warning signals and finally program skip to S156;

S154;

The computer will send not pre-warning instruction and the pre-warning devices will not send the pre-warning signals and finally the program skip to S160;

S156;

Calculating remainder time of the pre-warning,

L_t=L_t−

Δ

t, program skip to S160;

S160;

the value in the register D<sub>t+Δ

t</sub> will be transferred into the register D_t and then the program skip to S162;

S162;

The value in the register T_t will be transferred into the register T_o and then the program skip to S102.

6. A system for preventing rear end collision of vehicles is applied for a vehicles with electric fuel injection system, which comprises at least:

(1) an analog fuel-decreasing pre-warning electric control unit 24 comprising a voltage follower 2, a voltage differential circuit 3, a voltage comparator 4 and a pre-warning timing circuit 5;

the input port of voltage follower 2 is connected to the output port of the throttle sensor 1 of the electric fuel injection system;

the input port of the voltage differential circuit 3 is connected to the voltage output port of the voltage follower 2;

one input port of voltage comparator 4 is connected to the voltage output port of the voltage differential circuit 3 and the another input port is connected to the preset voltage R_p, the input port of pre-warning timing circuit 5 is connected to the output port of voltage comparator 4;

(2) an electric switch 6 installed between positive electrode of power supply and the pre-warning devices 7 and the input port of electric switch 6 is connected to the output port of the pre-warning timing circuit 5;

thus the electric switch 6 is controlled by the analog fuel-decreasing pre-warning electric control unit 24 and the pre-warning devices 7 is controlled by the electric switch 6;

under the controlling of the analog fuel-decreasing pre-warning electric control unit 24, the following operations can be finished;

(a) sampling from the throttle sensor 1 of the electric fuel injection system to get the analog throttle voltage D by the voltage follower 2;

(b) do the time differentiation operation to the analog throttle voltage D to get the analog voltage R_t of the throttle speed by the voltage differential circuit 3;

(c) comparing the analog voltage R_t of the throttle speed with the preset voltage R_p, when the pre-warning control condition is met, the pre-warning control signal will be generated by the voltage comparator 4;

(d) the pre-warning control signal will drive the electric switch 6 turned on, then the pre-warning devices 7 will send out the pre-warning signals to the following vehicles.

7. The system for preventing rear end collision of vehicles as in claim 6, the voltage follower 2 is consisted with a integrated operational amplifier LM158 and resistor R2 and R3;

one end of the resistor R2 is connected to the positive input port 3 of the LM158 and the another end of the resistor R2 is connected to the output port of the throttle sensor 1, here, the electric accelerator pedal sensor is used as the throttle sensor 1;

one end of the resistor R3 is connected to the negative input port 2 of the LM158 and another end of the resistor R3 is connected to the output port 1 of the LM158, the output voltage of the voltage follower 2 can follow the output voltage of the throttle sensor 1 in real time.

8. The system for preventing rear end collision of vehicles as in claim 6, the differential circuit 3 is consisted with the capacitor C5, resistor R6 and resistor R7;

one end of the resistor R6 is connected with the positive power supply and the other end of the resistor R6 is connected with one end of the resistor R7 and the another end of the resistor R7 is connected with ground;

the positive end of the capacitor C5 is connected to the output port 1 of the LM158 and the another end of the capacitor C5 is connected to cross point of the resistor R6 and resistor R7;

the positive end of the capacitor C5 is the input end of the differential circuit 3;

the negative side of the capacitor C5 is the output end of the differential circuit 3.

9. The system for preventing rear end collision of vehicles as in claim 6, the voltage comparator 4 is consisted with analog integrated circuit LM158 and the resistor R8, the positive input port 5 of the LM158 is connected to ground through the resistor R8 and the negative input port 6 of the LM158 is connected to the cross point of the resistor R6 and resistor R7 and the negative input port 6 of the LM158 is the input port of the voltage comparator 4 and the port 7 of the LM158 is the output port of the voltage comparator 4;

the output voltage of the voltage follower 2 will be underwent the differential operation in the differential circuit 3 and then the differential result will sum with the preset voltage R_p, if the voltage of the input port 6 of the LM158 equals to 0 or less 0, the output level of the voltage comparator 4 will jump from the low voltage to high positive voltage and this jump voltage is the pre-warning control signal.

10. The system for preventing rear end collision of vehicles as in claim 6, the pre-warning timing circuit 5 is consisted with the time-base circuit EN555, capacitor C9, C12 and C16, resistor R10, R13 and R15 and the diode D14;

the positive end of capacitor C9 is connected to the output port of the voltage comparator 4;

its negative end is connected to the threshold port 6 of NE555;

one end of resistor R10 is connected to the threshold port 6 of NE555 and its another end is connected with ground;

port 4 and port 8 of NE555 is connected to positive electrode of power supply;

port 1 of NE555 is connected with ground;

port 5 of NE555 is connected with ground through capacitor C12;

port 7 of NE555 is connected with positive electrode of power supply through resistor R13;

one end of resistor R15 and positive end of diode 14 are connected to port 3 of NE555;

other ends of the R15 and diode 14 are connected to port 2 of NE555;

positive end of capacitor C16 is connected to port 2 of NE555 and its negative end is connected with ground;

it is a typical monostable timing circuit with a positive trigger and negative output;

the input port of the timing circuit 5 is the threshold port 6 of NE555;

the output port of the timing circuit 5 is the discharge port 7 of NE555.

11. The system for preventing rear end collision of vehicles as in claim 6, the electric switch 6 is a high power semiconductors switch IRF9540, the gate electrode G of the IRF9540 is connected to the output port of the timing circuit 5 and the source electrode S of the IRF9540 is connected to the positive electrode of the power supply of the vehicles'"'"' system and its drain electrode D of the IRF9540 is connected to the positive power end of the brake lights.

12. The system for preventing rear end collision of vehicles as in claim 6, the electric accelerator pedal sensor in electric fuel injection system can be used as the throttle sensor 1.

13. The system for preventing rear end collision of vehicles as in claim 6, the throttle valve position sensor in electric fuel injection system can be used as the throttle sensor 1.

14. The system for preventing rear end collision of vehicles as in claim 6, the air flow meter in electric fuel injection system can be used as the throttle sensor 1.