WO2018215848A1

WO2018215848A1 - A suspension energy recovery system (sers) and a method thereof

Info

Publication number: WO2018215848A1
Application number: PCT/IB2018/051918
Authority: WO
Inventors: Rahul Kumar; Aditya M DESHPANDE; Aman K SAHA; Saroja V SIDDAMAL; Vivek Kumar
Original assignee: Rahul Kumar; Deshpande Aditya M; Saha Aman K; Siddamal Saroja V; Vivek Kumar
Priority date: 2017-05-25
Filing date: 2018-03-22
Publication date: 2018-11-29

Abstract

An energy recovery system 100 in a suspension system of an automobile, the energy recovery system comprising an energy recovery unit 101 coupled with a shock absorber 102. The energy recovery unit 101 further comprising a direction control valve 103, a control mechanism 105, a linear generator 106 and a power electronics unit 107 wherein the system is enabled to convert the linear motion obtained in the shock absorber to a reciprocating motion in the double acting cylinder using the direction control valve wherein the reciprocating motion enables the piston rod having the linear magnetic array to reciprocate in the linear stator to produce electrical energy which is stored in the electrical storage unit 108 via the power electronics unit 107.

Description

A SUSPENSION ENERGY RECOVERY SYSTEM (SERS) AND A METHOD THEREOF

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY

The present application claims priority from an Indian Provisional Application number 201741018339 filed on 25^th May 2017 and to a Completer After Provisional Application filed on 16^th March 2018.

TECHNICAL FIELD

The present invention relates generally to kinetic energy recovery system and method for automotive shock absorbers and more particularly, to an arrangement of hydro-pneumatic and electromechanical system and method that recovers energy from pressurized fluid during damping of shocks & vibrations during operation of such shock absorbers.

BACKGROUND

The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.

In automotive applications, shock absorber is an essential system provided to support road handling and ride quality. In addition to springs, shock absorbers are provided for damping the impact forces. Depending on road irregularities, shock absorbers allows cushioning of shocks by releasing energy from impact forces, by moving pressurized hydraulic fluid through orifices. The energy from impact forces is lost as heat from such shock absorbers.

Numerous developments in automotive technology have happened in past years to meet stricter emission norms, reduce tail pipe emissions and to improve vehicle efficiency by researchers and automobile manufacturers. For example, regenerative braking is standard and widely used in modern vehicles. Patent References US20140288776, US8376100B2, US20100072760 & EP1878598 describe a hydraulic system which uses a hydraulic motor to convert energy from shocks into electricity.

The flow of hydraulic fluid inside the shock absorber which is used as double acting reciprocating pump to direct pressurized fluid from a pressure chamber to the inlet of a rotary hydraulic motor which drives a rotating shaft connected to rotary electrical generator. The exhaust is then connected to a tank of exhaust chamber of double acting reciprocating pump. The rotary generator produces electrical energy and the back electromotive force produced due to load provides damping, which is controlled with power electronics. The system can be used in reverse by using rotary electrical generator as a motor, controlling fluid flow through the hydraulic motor, and adjusting piston position by pumping fluid in either chamber of double acting reciprocating pump. Since the system requires motion conversion and external energy source to operate the energy yield is comparatively low.

Patent reference WO2013167238 completely eliminates hydraulic shock absorber by disposing electric geared generator at suspension arm joints which is also used as a motor to adjust suspension system by drawing external power. The system requires gear mechanism which are bulky and leads to transmission losses which consequently results to a complex system with low energy yield and high cost.

Patent reference US7087342 discloses a system consisting of a power screw which rotates on shock absorber displacement driving an electrical alternator. The mechanical efficiency of such system is reduced due to mechanical losses from such mechanism.

Patent Reference US8874291, US9068623, US6952060B2 discloses a system of linear generator coupled with the shock absorber. Linear generators produce electrical power on linear motion of magnet array. The magnet array of linear generator moves at equal magnitude as of the piston displacement inside the shock absorber body. Even though complexity of design is reduced, to produce significant amount of electrical energy at such low displacements and frequencies such a system requires a bulky linear generator setup. Hence, cost and weight of such systems is a concern.

Thus, there is a need for a suspension energy recovery system for shock absorbers that addresses at least some of the above-mentioned drawbacks.

SUMMARY This summary is provided to introduce concepts related system and method for operating a managing discharge from a pump remotely and the concepts are further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

In an embodiment, an energy recovery system in a suspension system of an automobile is described. The energy recovery system comprises an energy recovery unit coupled with a shock absorber. The energy recovery unit further comprises a direction control valve enabled to direct the flow of a suspension fluid from the shock absorber to one of the two chambers of a double acting cylinder. The energy recovery unit further comprises a control mechanism comprising a sliding connector which is enabled to connect a spool shaft of the direction control valve and the piston rod of the double acting cylinder wherein the sliding connector comprising a slider on the spool shaft which slides between a first stopper and a second stopper. The energy recovery unit further comprises a linear generator 106 comprising a linear magnetic array on the end of the piston rod which is enabled to reciprocate in a linear stator. The energy recovery unit further comprises a power electronics unit enabled to convert the generated power and store the converted power in an electrical storage unit. The system is further enabled to convert the linear motion obtained in the shock absorber to a reciprocating motion in the double acting cylinder using the direction control valve wherein the reciprocating motion enables the piston rod having the linear magnetic array to reciprocate in the linear stator to produce electrical energy which is stored in the electrical storage unit via the power electronics unit.

In another embodiment, a method of energy recovery in a suspension system of an automobile is described. The method may comprise transmitting, via a direction control valve, compressed fluid from shock absorber to a first chamber of a double acting cylinder. The method may further comprise performing, via the pressure developed in the first chamber, an extension movement of the piston and rod assembly. The method may further comprise changing, via a control mechanism, the position of the spool shaft of to change the direction of flow of fluid from shock absorber to the double acting cylinder via the direction control valve. The method may further comprise transmitting, via a direction control valve, compressed fluid from shock absorber to a second chamber of the double acting cylinder. The method may further comprise performing, via the pressure developed in the second chamber, a retraction movement of the piston and rod assembly. The method may further comprise producing, via the plurality of extension and retraction movements, a reciprocating motion in the piston and rod assembly thereby resulting the magnetic array to reciprocate in the linear stator. The method may further comprise producing, via the magnetic array and linear stator, electrical energy which is stored in the electrical storage unit 108 via the power electronics unit.

BRIEF DESCRIPTION OF DRAWINGS

The detailed description is described with reference to the accompanying Figures. In the Figures, the left-most digit(s) of a reference number identifies the Figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.

Figure 1 illustrates an overall block diagram of suspension energy recovery system unit in accordance with an embodiment of the present disclosure.

Figure 2 illustrates a cross-sectional view of directional control valve, reciprocating cylinder and linear generator in accordance with an embodiment of the present subject matter. Figure 3 illustrates schematics of fluid flow, movement of control shaft, piston and magnet array during extension stroke in accordance with an embodiment of the present subject matter.

Figure 4 illustrates schematics of movement of fluid during directional control valve opening in accordance with an embodiment of the present subject matter.

Figure 5 illustrates schematics of fluid flow, movement of control shaft, piston and magnet array during retraction stroke in accordance with an embodiment of the present subject matter.

Figure 5 illustrates an enlarged cross-sectional view of spool shifting mechanism in accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION The present invention relates generally to kinetic energy recovery system and method for automotive shock absorbers and more particularly, to an arrangement of hydro-pneumatic and electromechanical system and method of recovering energy from pressurized fluid during damping of shocks & vibrations during operation of such shock absorbers.

Referring Figure 1, a basic layout of a suspension energy recovery system 100 is illustrated in accordance with an embodiment of the present subject matter. The suspension energy recovery system 100 recuperates energy from shock absorption in a typical road vehicle that has an energy recovery unit 101, integrated to shock absorber 102, of a typical road vehicle (not shown) acting as a pump. The suspension energy recovery unit 101 comprises a direction control valve 103, a double acting cylinder 104 and a control mechanism 105. The double acting cylinder 104 is enabled to produce high frequency reciprocating linear motion wherein such reciprocating linear motion is fed to a linear generator unit 106. The linear generator unit 106 is enabled to convert kinetic energy to electrical energy. The generated electrical energy is controlled via a power electronics unit 107 and may be fed to an electrical storage unit 108, or power auxiliary in-vehicle systems 109. Referring Figure 2, an enlarged cut-sectional view of the suspension energy recovery unit 101 is illustrated in accordance with an embodiment of the current subject matter. Figure 2 will now be referred to explain the constructional features of suspension energy recovery unit 101 further comprising a directional control valve manifold 110, having five ports- inlet port 116, exhaust port 117, exhaust port 118, port 120 and port 121. Exhaust port 117 and 118 may be connected together to form a common exhaust port (not shown). A spool shaft 114 is placed concentrically to the axis of directional control valve 110 such that it slides inside the direction control valve manifold 110. The spool shaft 114 comprise of a first spool 135 and a second spool 136 which are placed concentrically at a distance from each other on one end of the spool shaft 114 and each spool slides along with the spool shaft 114, inside the directional control valve manifold 110. On another end of the spool shaft 114, a first stopper 133 and a second stopper 134 are placed concentrically at a distance with each other which moves along with the spool shaft 114. Port 120 and port 121, of directional control valve manifold 110, are connected to first port 122 and second port 123, respectively of a double acting cylinder manifold 111. First port 122 is connected to the first chamber 125 and second port 123 is connected to second chamber 124 of double acting cylinder manifold 111. The second chamber 124 and first chamber 125 are separated by a piston 137 which connects to piston rod 138 at one end concentrically and moves along with the piston 137. A sliding connector 119 is fixed at another end of the piston which extends to slider 132. The slider 132, slides on top of spool shaft on movement of piston rod 138. The piston rod 138 is further connected to linear magnet array 112 which comprises of an array of magnets 126, 127, and 128, placed at a distance such that like poles face each other. The linear magnet array 112 may consists of more or less number of magnets than mentioned. The linear motor 112 is placed concentric to the axis of piston rod 138 and moves along with the piston rods 138. Stator 113 comprises of stator windings 129, 130 and 131 placed concentric to the axis of linear magnet array 112, at a distance and are fixed at their position. Stator 113, may consists of more or less number of copper windings connected in series or parallel than mentioned.

Referring Figure 3, Figure 4 and Figure 5 illustrate fluid flow inside the directional control valve manifold 110 and double acting cylinder manifold 111, movement of piston 137, piston rod 138, sliding connector 119 and slider 132 of Fig 2 during operation of suspension energy recovery unit 101.

In an embodiment, constructional details as mentioned in description of Figure 2 will now be referred to explain Figure 3, Figure 4 and Figure 5.

Referring Figure 3, a schematic of the suspension energy recovery unit 101 is illustrated in accordance with an embodiment of the subject matter, when the piston and rod assembly 139 is in extension stroke.

The shock absorber cylinder may act as a fluid pump (not shown) providing unidirectional fluid flow, which is already known concept according to the provided prior art and hence not explained in this document. On displacement at shock absorber piston, fluid inside it pressurizes. The pressurized fluid enters the directional control valve manifold 110, through inlet port 116 as shown in Figure 3. The spool shaft 114, is at a position such that pressurized fluid from inlet port 116 is allowed to enter only in port 120, of directional control valve manifold 110. The pressurized fluid flows from inlet port 116 through first port 122 and enters first chamber 125 of double acting cylinder manifold 111. This increases pressure in first chamber 125 and forces piston and rod assembly 139 to extend. The displacement of piston and rod assembly 139 causes decrease in volume of second chamber 124 and displaces fluid inside it, through second port 123, to port 121 and thereafter displaced fluid is removed from the system through exhaust port 117 of directional control valve manifold 110. Along with the piston and rod assembly 139, slider 132 also displaces its position along the axis of spool shaft 114 and comes in contact with second stopper 134. During its displacement slider 132, gather inertia forces which moves the stopper 134 along with spool shaft 114 as shown in Figure 4.

Referring Figure 4, a schematic of the suspension energy recovery unit 101 when the piston and rod assembly 139, completes it extension stroke and spool shaft change its position is illustrated in accordance with an embodiment of the current subject matter. Since, the spool shaft 114 has changed its position, the inlet port 116 now allows fluid to enter only in port 121, of directional control valve manifold 110. The pressurized fluid flows from inlet port 116 through second port 121 and enters second chamber 124 of double acting cylinder manifold 111. Exhaust port 118 of directional control valve manifold 110, is now connected to first chamber 125 of double acting cylinder manifold 111.

The increase in pressure in second chamber 124 forces piston and rod assembly 139 to retract as illustrated in Figure 5.

Referring Figure 5, a schematic of the suspension energy recovery unit 101 when the piston and rod assembly 139 is in retraction stroke, is illustrated in accordance with an embodiment of the present subject matter. The pressurized fluid enters the directional control valve manifold 110, through inlet port 116. The spool shaft 114, is at a position such that pressurized fluid from inlet port 116 is allowed to enter only in port 121, of directional control valve manifold 110. The pressurized fluid flows from inlet port 116 through second port 121 and enters second chamber 124 of double acting cylinder manifold 111. The increase in pressure in second chamber 124 forces piston and rod assembly 139 to retract. The displacement of piston and rod assembly 139 causes decrease in volume of first chamber 125 and displaces fluid inside it through first port 122 to port 120 and thereafter displaced fluid is removed from the system through exhaust port 118 of directional control valve manifold 110. Along with the piston and rod assembly 139, slider 132 also displaces its position along the axis of spool shaft 114 and comes in contact with first stopper 133.

During its displacement slider 132, gather inertia forces which moves the stopper 134 along with spool shaft 114.

The system repeats the cycle as explained in Figure 3, Figure 4 and Figure 5, creating high frequency linear reciprocating motion of the linear magnet array 112. This causes high frequency movement of magnetic field lines across the stator 113 inducing alternating current and voltage. The stator 113 may consist of one or more stator windings 129 connected in series or parallel to provide required power output. The back electromotive force generated by the linear generator 106 provides for damping of shocks and vibrations in shock absorber.

Referring Figure 6, other possible ways of control mechanism 105, wherein magnets 140 and 141 are placed such that like poles face each other are illustrated in accordance with an embodiment of the current subject matter. The slider 132 may be made of magnetic material and stopper 133 and 134 of non-magnetic material. When piston and rod assembly retract or extends the magnets 140 and 141 exert attractive forces which further assists in switching position of spool shaft 114. Additional mechanical spring 142 and mechanical spring 143 can also be placed such that they compress alternatively on extension or retraction stroke of piston and rod assembly 139 because of the displacement of slider 132. Mechanical spring 142 and 143 store extra energy on compression and releases it when the spool shaft 114 is shifting its position which assists switching of spool shaft 114 maintaining smooth and consistent fluid flow throughout the circuit.

Although implementations for the implementations for the suspension energy recovery system (SERS) and method thereof are described have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations for the suspension energy recovery system (SERS) and method thereof.

Claims

We Claim:

1. An energy recovery system 100 in a suspension system of an automobile, the energy recovery system 100 comprising:

an energy recovery unit 101 coupled with a shock absorber 102;

the energy recovery unit 101 further comprising

a direction control valve 103 enabled to direct the flow of a suspension fluid from the shock absorber 102 to one of the two chambers of a double acting cylinder 104;

a control mechanism 105 comprising a sliding connector 119 which is enabled to connect a spool shaft 114 of the direction control valve 103 and the piston rod 138 of the double acting cylinder 104 wherein the sliding connector 119 comprising a slider 132 on the spool shaft 114 which slides between a first stopper 133 and a second stopper 134;

a linear generator 106 comprising a linear magnetic array 112 on the end of the piston rod 138 which is enabled to reciprocate in a linear stator 113;

a power electronics unit 107 enabled to convert the generated power and store the converted power in an electrical storage unit 108;

wherein the system 100 is enabled to convert the linear motion obtained in the shock absorber 102 to a reciprocating motion in the double acting cylinder 104 using the direction control valve 103 wherein the reciprocating motion enables the piston rod 138 having the linear magnetic array 112 to reciprocate in the linear stator 113 to produce electrical energy which is stored in the electrical storage unit 108 via the power electronics unit 107.

2. The energy recovery system 100 of claim 1, wherein the direction control valve 103 comprises an inlet port 116, an first exhaust port 117, a second exhaust port 118, a port 120 and a port 121.

3. The energy recovery system 100 of claim 1, wherein the spool shaft 114 comprises a first spool 135 and a second spool 136 which are placed concentrically at the first end of the spool shaft.

4. The energy recovery system 100 of claim 1, wherein the second end of the spool shaft 114 comprises the first stopper 133 and the second stopper 134 which move along the spool shaft 114 and are driven by the slider 132 enabling a linear motion for the spool shaft 114.

5. The energy recovery system 100 of claim 1, wherein the port 120 is configured to connect the first port 122 and the port 121 is configured to connect the second port 123 of the double acting cylinder 104.

6. The energy recovery system of claim 1, wherein an extension stroke is performed when the pressurised fluid from inlet port 116 enter the first port 122 via the port 120 thereby filling the first chamber 125 of the double acting cylinder 104 which further increases the pressure in the first chamber 125 resulting in the movement of the piston and rod assembly 139.

7. The energy recovery system of claim 1, wherein the spool shaft changes the position at the end of the extension stroke with the aid of the control mechanism 105 to initiate the retraction stroke.

8. The energy recovery system of claim 1, wherein a retraction stroke is performed when the pressurised fluid from inlet port 116 enters the second port 123 via the port 121 thereby filling the second chamber 124 of the double acting cylinder 104 which further increases the pressure in the second chamber 124 resulting in the movement of the piston and rod assembly 139.

9. The energy recovery system of claim 1, wherein the spool shaft 114 changes the position at the end of the retraction stroke with the aid of the control mechanism 105 to initiate the extension stroke.

10. The energy recovery system of claim 1, wherein the extension stroke and retraction stroke enable the piston rod 138 to create reciprocating motion and further to reciprocate the magnetic array 112 in the linear stator 113.

11. The energy recovery system of claim 1, the linear magnetic array 112 comprises an array of magnets 126, 127 and 128 wherein the like poles of magnet face each other.

12. The energy recovery system of claim 1, the slider 132 is composed of magnetic material and the stopper 133 and 134 are composed of non-magnetic material wherein the magnets 140 and 141 exert force of attraction when the piston and rod assembly 139 perform retraction or extension movements.

13. The energy recovery system of claim 1, wherein the control mechanism 105 optionally comprises two mechanical springs 142 and 143 placed on the spool shaft 114 which compress alternatively on extension or retraction stroke of the piston and rod assembly 139 due to the movement of the slider 132 wherein the mechanical spring 142 and 143 store energy on compression and release the energy when the spool shaft 114 is shifting the position for assisting the switching of spool shaft 114.

14. A method of energy recovery in a suspension system of an automobile, the method comprising: transmitting, via a direction control valve 103, compressed fluid from shock absorber

102 to a first chamber 125 of a double acting cylinder 104; performing, via the pressure developed in the first chamber 125, an extension movement of the piston and rod assembly 139; changing, via a control mechanism 105, the position of the spool shaft 114 of to change the direction of flow of fluid from shock absorber 102 to the double acting cylinder 104 via the direction control valve 103; transmitting, via a direction control valve 103, compressed fluid from shock absorber 102 to a second chamber 124 of the double acting cylinder 104; performing, via the pressure developed in the second chamber 124, a retraction movement of the piston and rod assembly 139; producing, via the plurality of extension and retraction movements, a reciprocating motion in the piston and rod assembly 139 thereby resulting the magnetic array 112 to reciprocate in the linear stator 113; producing, via the magnetic array 112 and linear stator 113, electrical energy which is stored in the electrical storage unit 108 via the power electronics unit 107.