The present invention relates to system of regulating the rate at which power is supplied to a brake system. More specifically, the invention relates to a system employing a controller and an intermediate device, which is driven by an engine and which drives a brake power source, to regulate the rate at which the power source supplies power to the brake system.
The principles governing the deceleration and stopping of a motor vehicle are generally well known. A moving vehicle possesses kinetic energy, which must be removed in order for the vehicle to slow or stop. This removal of kinetic energy is most generally achieved by converting this energy into heat via friction. Hence, if a driver of a vehicle desires to slow or stop a vehicle faster than the vehicle would normally slow or stop as a result of the frictional force between the vehicle's wheels and the road, an additional frictional force must be applied. This additional conversion of kinetic energy into heat is usually performed by applying a contact material—typically in the form of a block or a pad—to the rotating wheels or to discs attached to the axles. As friction is created and the kinetic energy is thereby converted into heat, the wheels slow down and eventually the vehicle stops.
In order to apply this contact material, a power supply is obviously required. Systems for supplying power to a brake system are also generally well known, and typically include a power source, such as a compressor or an electric generator, that is driven by the crankshaft of the vehicle's engine. Such an arrangement allows power to be continuously available, which may be required for a variety of reasons. For example, in cases where the power is utilized to engage the braking mechanism, such as by causing a caliper to pinch a rotating disc, a driver who wants to brake often or immediately on demand will always have the appropriate power available to power the caliper. Similarly, in cases where power is needed to disengage the braking mechanism, such as in the case where a caliper is normally biased against a rotating disc by a spring, which must be biased in the opposite direction by pressurized fluid in order to release the brakes, power can be supplied to the braking system continuously in order to keep the vehicle moving.
However, one disadvantage with this way of supplying power to the brake system occurs in vehicles that operate at low engine speeds for long periods of time, such as inter-city buses, school buses, and refuge trucks. As a result, the power supply must be very large in order to meet the overall needs of the vehicle's braking system.
What is desired, therefore, is a system of supplying power to a brake system that permits engines to run at low speeds for long periods of time. What is further desired is a system of supplying power to a brake system that does not require the use of a large power source. What is also desired is a system of supplying power to a brake system that conserves energy.
Accordingly, it is an object of the present invention to provide a system for regulating the supply of power to a brake system that does not require the use of a large power source in vehicles where the engine must run at low speeds for long periods of time.
It is a further object of the present invention to provide a system for regulating the supply of power to a brake system that conserves energy when the brake system does not require power.
To overcome the deficiencies of the prior art and to achieve at least some of the objects and advantages listed, the invention comprises a system for regulating the supply of power to a vehicle's brake system, including an engine, an intermediary device driven by the engine, a brake power source driven by the intermediary device, a brake system powered by the brake power source, and a controller in communication with the intermediary device, the controller, in response to a minimum engine speed, causing the intermediary device to drive the brake power source at a desired rate.
In another embodiment, the invention comprises a system for regulating the supply of power to a vehicle's brake system, including an engine, an intermediary device driven by the engine, a source of pressurized fluid driven by the intermediary device, a brake system powered by the source of pressurized fluid, and an electronic control unit in communication with the intermediary device, the controller, in response to a minimum engine speed, causing the intermediary device to drive the source of pressurized fluid at a desired rate.
In yet another embodiment, the invention comprises a system for regulating the supply of power to a vehicle's brake system, including an engine, an intermediary device driven by the engine, a source of electricity driven by the intermediary device, a brake system powered by the source of electricity, and an electronic control unit in communication with the intermediary device, the controller, in response to a minimum engine speed, causing the intermediary device to drive the source of electricity at a desired rate.
The basic components of one embodiment of a system 20 for regulating the supply of power to a vehicle's brake system in accordance with the invention are illustrated in
Typically, the controller 30 is an electronic control unit (ECU). In certain embodiments, an operator of the vehicle can effect complete control over the electronic control unit 30, and thus, can directly regulate the rate at which the intermediate device 24 drives the brake power source 26. In other embodiments, the electronic control unit 30 has one or more inputs that effect the rate at which the brake power source 26 is driven, as is further explained below.
In certain embodiments, the intermediate device 24 includes two separately housed components. The basic components of one such embodiment of the intermediate device 24 are illustrated in
The basic components of another intermediate device 24 including two separately house components is illustrated in
As illustrated in
As another example, as illustrated in
The electronic control unit 30 regulates the operation of either the pump 64 or the motor 66, or both, in order to control the speed at which the motor 66 drives the brake power source 26. In this way, the speed at which the brake power source 26 is driven can be controlled irrespective of the current engine speed.
As illustrated in
The brake power source 26 may be an electric, pneumatic, or other type of power source suitable for powering a brake system. For example, as illustrated in
As illustrated in
In these embodiments, the air is transferred to the braking mechanism 80. In certain of these embodiments, the transfer of this air is initiated or terminated, either automatically or by the operator of a vehicle, by opening or closing a valve 86 with a valve actuator 88. In some of these embodiments, a reservoir 74 is provided in order to hold air compressed by the compressor 72 until it is needed, at which time the valve 86 is actuated with the valve actuator 88.
As illustrated in
In certain advantageous embodiments, the braking mechanism 80 also includes a separate contact device actuator 92 for actuating the device that actually creates the frictional force. In these embodiments, the actuator 92 receives the power from the brake power supply and, powered by it, supplies power in another form to the contact device 90.
The control of the brake power source 26 in this manner will often be valuable for its ability to determine when power is supplied to the brake system 28, such as in cases where the power is used to actuate the contact device 90. However, it should be noted that this control of the brake power source 26 is also valuable for its ability to determine when power will not be supplied to the brake system 28. Such instances occur when the power supplied by the brake power source 26 is used to prevent the braking mechanism 80 from braking the vehicle, and the braking mechanism 80 is actuated by interrupting the flow of power from the brake power source 26, such as, for example, in the case of a spring actuator where, during normal operation of the vehicle, compressed air is used to bias the spring and thereby prevent the spring from exerting a force on the contact device 90, and thus, the spring is only able to actuate the contact device when the flow of compressed air is interrupted.
It should be understood that the foregoing is illustrative and not limiting, and that obvious modifications may be made by those skilled in the art without departing from the spirit of the invention. Accordingly, reference should be made primarily to the accompanying claims, rather than the foregoing specification, to determine the scope of the invention.