WO2013024491A2

WO2013024491A2 - Anti roll back system for manual transmission vehicles

Info

Publication number: WO2013024491A2
Application number: PCT/IN2012/000461
Authority: WO
Inventors: Mahesh SHAHAPURE; Arun BISHT; Abhishek JADHAV; Jaydeep GANGURDE
Original assignee: Knorr-Bremse Systems For Commercials Vehicle India Pvt Ltd
Priority date: 2011-06-28
Filing date: 2012-06-28
Publication date: 2013-02-21
Also published as: BR112013033523A2; WO2013024491A3; CN103687764B; RU2014102612A; BR112013033523B1; CN103687764A; RU2586918C2

Abstract

An anti roll back system for manual transmission vehicles is disclosed. The system includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a diverting means and a flow control means. The improvement comprises the system working in conjunction with a vehicle braking. When the vehicle is stationary and inclined, upon releasing the brakes, the flow control means releases the air from the rear brake actuator at a slow rate which enables to maintain the vehicle stationary even after the brakes are released. The slow release of air provides some time that enables driver to accelerate the vehicle to roll up the hills in intended direction against the slope of inclined surface.

Description

Anti Roll Back System for Manual Transmission Vehicles

Field of the invention

The present invention relates to an anti-roll back system for vehicles, and more particularly, the present invention relates to an anti roll back system for vehicles having manual transmission for preventing the vehicles from rolling backward inadvertently when starting from stopped condition on an upwardly slanted roadway.

Background of the invention

While start up a vehicle from stopped condition on upwardly slanted roadway and against slope, a driver faces various difficulty. To drive the vehicle, the driver has to release brake using right le and being a common leg to press accelerator. But due to slope and timelag between the brake release and the required torque generation, vehicle starts rolling backing off and may hit following vehicle/obstacle.

To avoid this situation, the driver has to learn special skill of shifting his/her leg between brake and accelerator, press half clutch or use parking brake and so on. However, this is skill dependent and over/under estimation by the driver may result in an accident. After learning all these skills, the driver may not be able to handle all situations due to changing external environment like vehicle loading, gradient angle, road surface, engine capacity to generate torque, and the like.

Additionally, the driver may face this situation while_^ reversing the vehicle. The magnitude of difficulty depends mainly on amount of slope, load on vehicle, drivers' own experience and his tuning with the vehicle. Not accomplishing this task successfully may result into one or the other type of road accident. Currently, some higher end vehicles are equipped with feature called 'Hill Start Aid (HSA), Hill Holder, Hill Start Assist Control (HAC) and the like. This feature assists the driver while driving the vehicles against steep gradient. These systems are already effective, but basic system is electronics based logic control and needs additional input and outputs like torque, vehicle gradient, traction control valve etc. The higher end vehicle are usually equipped with many electronic control units and sensors through which 'Hill Start' system can get inputs and accordingly control output valves through which brake can be applied and released.

However, it is difficult and expensive to implement these systems in conventional vehicles due to many limitations such as lack of electronic control units, sensors, and the like in conventional vehicles. Conventional vehicles are usually equipped with basic brake system and mechanical engine with manual transmission.

Prior Art:

Driver's Skill: When a vehicle is stationary using main service brake on an uphill slope and is to start driving again without rolling backward, it is usual for the driver to first keep vehicle held stationary using main service foot brake, engage the suitable gear for suitable torque based on judgment, then quickly release the footbrake & operate clutch & accelerator in such a way that vehicle positively rolls up in required direction & it must not roll back or engine must not stop running. In some situations driver has to release brake & press accelerator at the same time using same right leg. This method of driving off on inclination against the slope is highly dependent on driver's skill & judgment. Driver may not acquire this skill very easily due to may variable like change in load conditions, changing vehicle loading patterns with respect to vehicle center of gravity, vehicle engine & transmission condition, inclination angle, etc.

However, in absence of this skill there is an huge risk that the vehicle may, for example, start to roll or move forward in an uncontrolled manner with serious damage as a consequence. This may happen if, for example, the driver delays the release and/or the brake system loses pressure more quickly than expected, for example if a component is slightly leaky. Electronic system:

This system also requires one or more sensors which detect the statues in the drive line of the vehicle, and an inclination sensor which senses whether the vehicle is on an uphill gradient. Further, the electronic system also includes sensors or calculation models for estimating the state of the brake pedal and the accelerator pedal, the torque of the engine, the total weight of the vehicle and the like.

However, disadvantage of this system is that it would need high end vehicle with electronic features which can provide this electronic Hill Start Assist feature. Such high end electronics is not available in majority of convensional vehicles.

Use of Parking Brake:

Parking brake or hand brake is mainly used when stopping the vehicle for relatively longer time, such as when loading or unloading, or for launch or for over night stay, etc. in conventional vehicles, parking brake can also be used to avoid rollback. Here, while the vehicle is held on inclination using main service brake, the driver applyies parking brake then release main service brake by lifting right leg from main service brake & starts pressing accelerator & simultaneously release the parking brake gradually until the vehicle develops the required torque to move in required direction against the slope of gradient. However, it is difficult to release the Parking brake in a graduated manner as this requires very special skill as well as a clear space around the vehicle. However, in absence of this skill there is an huge risk that the vehicle may, for example, start to roll or move forward in an uncontrolled manner with serious damage as a consequence. This may happen if, for example, the driver is delays the release and/or the brake system loses pressure more quickly than expected, for example if a component is slightly leaky.

Accordingly, there exist a need to provides an anti roll back system for manual transmission vehicles which overcomes the drawbacks of the prior art.

Objects of the present invention

An object of the present invention is to provide a anti-roll back system for vehicles, which can effectively and easily support driver while driving up on steep gradient in forward or reverse direction and yet overcome limitations of prior art systems.

Another object of the present invention is to provide an anti-roll back system for vehicles, which is capable of being fitted on any vehicle having fluid (gas or liquid), operated braking system. Yet another object of the present invention is to provide an anti-roll back system for vehicles, which is capable of being retrofitted on existing vehicles with minor vehicle modifications. Still another object of the present invention is to provide an anti-roll back system for vehicles, which is capable of being operated without any inputs from vehicle related to torque, speed, gradient, and the like. Further object of the present invention is to provide an anti- roll back system for vehicles, which is capable of supporting the vehicle moving in reverse gear and the vehicle rising on a gradient.

Another object of the present invention is to provide an anti- roll back system for vehicles, which doesn't intervene in normal driving situations, such as when driving on relatively flat road, when the vehicle is not stationary or driver doesn't need this system to intervene.

Yet another object of the present invention is to provide an anti- roll back system for vehicles, which operates without affecting basic braking system performance and doesn't allow complete brake system failure in case if anti roll back system itself fails.

Additionally one more object of the present invention is to provide an anti roll back system which can gradually & slowly release the brake for certain duration so that the driver can get time to feel & fine tune the torque generated to smoothly drive off the vehicle uphill against the slope of gradient

One more object of the present invention is to provide an anti roll back system for vehicles, which is cost effective, easy to manufacture, easy for servicing and maintenance. Summary of the invention

Accordingly, the present invention provides an anti roll back system for manual transmission vehicles, the vehicles braking having a first reservoir, a front brake actuator operated by pressurized air from the first reservoir, a second reservoir, a rear brake actuator operated by pressurized air from the second reservoir, and a foot brake valve, the system comprising:

a first switch to be activated for activation of a electrical circuit;

a second switch capable of being activated upon sensing zero speed of the vehicle thereby closing the electrical circuit to pass current therethrough;

a third switch capable of being activated upon sensing positive inclination of the vehicle;

a fourth switch capable of being activated upon sensing negative inclination of the vehicle;

a fifth switch capable of being activated when the vehicle in a reverse gear; a diverting means for diverting the pressurized air received from the second reservoir upon operating the foot brake valve to either a first outlet or a second outlet, the first outlet being open when either the first switch, the second switch and the third switch are closed or the first switch, the second switch, the fourth switch and fifth switch are closed; and

a flow control means capable of controlling supply and release of the pressurized air from the rear brake actuator, wherein the flow control means is connected to the first outlet,

wherein when the vehicle is stationary and inclined, upon releasing the brakes, the flow control means releases the air from the rear brake actuator at a slow rate which enables to maintain the vehicle stationary even after the brakes are released and the slow release of air provides some time that enables driver to feel & accelerate the vehicle to roll up the hills in either forward direction or reverse direction, and when the vehicle is on normal road, the diverting means opens the second outlet which allows normal release of air from the rear brake actuator after releasing the breaks thereby keeping the anti-roll back system inoperative.

Typically, wherein the first switch and the second switch are electric switches.

Typically, wherein the zero speed of the vehicle is sensed by sensing the air pressure of the rear brake actuator.

Typically, wherein the zero speed of the vehicle is sensed by taking inputs from vehicle speed sensing means.

Typically, wherein while driving off on inclination, slow exhaust of air, supports the driver to feel that the torque generated by pressing accelerator is optimum to drive off in desired direction.

Brief description of the invention

Figure 1 shows a schematic drawing of an anti- roll back system using pneumatic actuator, in accordance with the present invention.

Detail description of the invention

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides an anti- roll back system, which effectively and easily supports driver while driving up on steep gradient in forward or reverse direction. The system is capable of being fitted on any vehicle having fluid (gas or liquid) operated braking system. Further, the system is capable of being retrofitted on existing vehicles with minor vehicle modifications. Furthermore, the system operates without affecting basic braking system performance of the vehicle and doesn't allow complete brake system failure in case if anti roll back system itself fails.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description. Referring now to figure 1, a schematic drawing of an anti- roll back system (herein after referred as the "system (100)") for manual transmission vehicles using pneumatic actuator in accordance with the present invention is illustrated. The system (100) includes a first switch (10), a second switch (20), a third switch (30), a fourth switch (40), a fifth switch (50), a diverting means (60) and a flow control means (70). The improvement comprises the system (100) working in conjunction with a vehicle braking (80). Generally, a vehicle braking (80) includes a front brake actuator (82), a first reservoir (84), a second reservoir (86), a foot brake valve (88) and a rear brake actuator (90). The front brake actuator (82) is operated by pressurized air from the first reservoir (84) and the rear brake actuator (90) is operated by pressurized air from the second reservoir (86). The system (100) is connected only to the rear brake actuator (90) therefore failure of the system (100) does not affect working of front brakes of the vehicle thereby preventing complete failure of braking system.

The first switch (10) is a manually operating switch, which a driver driving the vehicle needs to operate to activate the system (100). Specifically, the first switch (10) to be activated for activation of a electrical circuit of the system (100). In an embodiment, the first switch ( 10) is an electric switch. Further, the second switch (20) operates (closes electrical circuit to pass current therethrough) automatically upon sensing zero speed of the vehicle. In an embodiment, the second switch (20) is an electric switch. The zero speed of the vehicle is sensed either by sensing air pressure of the rear brake actuator (90) or by sensing and taking inputs from a vehicle speed sensor (speedometer) displaying speed on a dashboard or instrument cluster or any other vehicle speed sensing means. However, it may be evident to those skilled in the art use any other sensing mechanism for sensing the speed of the vehicle. The third switch (30) is an inclination sensing switch, which operates upon sensing inclination of the vehicle. More particularly, the third switch (3) is capable of sensing positive inclination of the vehicle. The positive inclination means the inclination of the vehicle on a upwardly slanted roadway while vehicle is rising on the hill in forward direction.

The fourth switch (40) is also an inclination sensing switch, which operates upon sensing inclination of the vehicle. More particularly, the fourth switch (40) is capable of sensing negative inclination of the vehicle. The negative inclination means the inclination of the vehicle on a downwardly slanted roadway while vehicle is moving in reverse direction rising on the hill.

The fifth switch (50) is a relay contact which operates when the driver puts vehicle in a reverse gear. The fourth switch (40) and the fifth switch (50) operates when the vehicle is rising on the hill in the reverse gear, and when the third switch (30) remains open. The diverting means (60) is an electro-pneumatic device, which enables diverting the pressurized air received upon operating the foot brake valve (88) from the second reservoir (86) to either a first outlet (60a) or a second outlet (60b). Further, the first outlet (60a) is open when the either the first switch (10), the second switch (20) and the third switch (30) are closed or the first switch (10), the second switch (20), the fourth switch (40) and fifth switch (50) are closed. This condition indicates that the driver wants to operate the system, the vehicle is stationary and the vehicle is inclined (either positive inclination or negative inclination). In this condition, the first outlet (60a) is connected to the flow control means (70). The flow control means (70) is capable of controlling supply and release of pressurized air to the rear brake actuator (90). Upon releasing the brakes by the driver, the flow control means (70) releases the air from the rear brake actuator (90) at a substantially slow rate from a small controlled flow valve (not shown) of the flow control means (70). This enables to maintain the vehicle stationary even after the brakes are released and the slow release of air provides some time that enables the driver to accelerate the vehicle to roll up the hills in either forward direction or reverse direction. The driver uses this time for pressing the accelerator and release clutch to generate sufficient torque to hold or pull the vehicle against gravitational force and start moving in desired direction.

On normal flat road if driver stops the vehicle by applying the main service brake & even if the first switch (10) is ON, the diverting means (60) remains in the default status where rear brake application and release takes place through second outlet (60b) which is normal operation as there is no inclination, the third switch (30) and the fourth switch (40) remains open keeping system (100) un-opera able .

On inclinated road or flat road, if the vehicle is being driven at certain speed and if driver operates brake to slow down the vehicle and if the first switch (10) is ON, the diverting means (60) remains in the default status where rear brake application and release takes place through second outlet (60b) which is normal operation as the vehicle speed is not zero, the second switch (20) remains open keeping system (100) un-opera able Advantages of the present invention:

1. The system (100) is capable of being installed on any basic vehicle without adding any sophisticated electronics systems and sensors.

2. The system (100) improves reliability due to use of less number of parts and avoiding, electronics.

3. No interfacing is required with other systems of vehicle and the decision making of the system (100) is based on inbuilt intelligence and simple generic inputs from vehicle.

4. The system (100) economical to manufacture.

5. The system (100) can work on vehicles with manual as well as automatic transmission even if there is no automatic traction control on vehicle.

6. The system (100) can be retro fitted on existing field vehicles.

7. Slow release of air during driving off on inclination, supports the driver in feeling and fine-tuning the clutch and accelerator to generate optimum engine torque for driving-off in desired direction. This feature of feeling is important as inabsence of this feel, driver may generate over torque which may result sudden & jurkey start & may also damage transmissions mechanism, where as lower torque may result in to vehicle rolling back

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention described in the present embodiment. Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure, or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention.

Claims

We Claim

1. An anti roll back system for manual transmission vehicles, the vehicles braking having a first reservoir, a front brake actuator operated by pressurized air from the first reservoir, a second reservoir, a rear brake actuator operated by pressurized air from the second reservoir, and a foot brake valve, the system comprising:

a first switch to be activated for activation of an electrical circuit;

wherein when the vehicle is stationary and inclined, upon releasing the brakes, the flow control means releases the air from the rear brake actuator at a slow rate which enables to maintain the vehicle stationary even after the brakes are released and the slow release of air provides some time that enables driver to accelerate the vehicle to roll up the hills in either forward direction or reverse direction, and when the vehicle is on normal road, the first switch is operated, the diverting means opens the second outlet which allows normal release of air from the rear brake actuator after releasing the breaks thereby keeping the system inoperative.

2. The anti roll back system as claimed in claim 1, wherein the first switch and the second switch are electric switches.

3. The anti roll back system as claimed in claim 1, wherein the zero speed of the vehicle is sensed by sensing the air pressure of the rear brake actuator.

4. The anti roll back system as claimed in claim 1, wherein the zero speed of the vehicle is sensed by taking inputs from vehicle speed sensing means.

5. The anti roll back system as claimed in claim 1, wherein while driving off on inclination, slow exhaust of air, supports the driver to feel that the torque generated by pressing accelerator is optimum to drive off in desired direction.