DE19722254C2 - Device for extracting thermal energy from vehicle friction brake systems - Google Patents

Description

The invention relates to a device for decoupling heat Energy from vehicle friction brake systems for heating purposes the passenger compartment, with parts of the in the wheel or axle area arranged service brakes and at least one heat exchanger are flowed through by a heat transfer medium.

When the outside temperature is low, motor vehicles are included Internal combustion engines use the heat for heating the Passenger cell usually from the heated engine cooling water. Nowadays the efficiency of combustion engines are constantly improving, which has the consequence that the decreasing engine heat for the passenger compartment heating decreases. The problem with modern, low-consumption die is drastic direct injection engines. With these engines only approx. 25% of the chemical energy released in the fuel delivered to the engine cooling water. In cold weather and in Stop-and-go operation, the heating output is no longer sufficient to a well-being of the occupants or fog-free vehicle ticket to ensure ben. The lack of heat must be caused by a auxiliary heating operated with fossil fuel. This makes the fuel economy advantage of combustion engine partially consumed again.

In addition or as an alternative to conventional auxiliary heating are u. a. in Scandinavia and Canada with some vehicle types  electric heaters. These devices consist of electric heating elements that u. a. in the cooling circuit the engine cooling are arranged. They warm up before starting the journey the coolant and sometimes also the passenger compartment. Since the Electricity for the heating elements is taken from stationary sockets this heat source is not available during the journey addition. In addition, primary energy consumption is excessive here average high.

Latent heat storage is used in a few vehicle types. With this system, excess thermi cal energy of the coolant in the form of heat of fusion in one thermally insulated container stored. The next cold the stored heat is returned to the coolant fed. For vehicles with low engine power, the Efficiency low, because on the one hand the memory for shorter trips only insufficiently charged and secondly the additional device importance of the relatively heavy storage tank the fuel consumption need of the vehicle increased.

Other heat suppliers are additional brakes. They are called dhows Braking preferably installed in commercial vehicles. With a we belstrombrake is the kinetic energy via electrical indu decorated eddy currents converted into partially usable thermal energy delt. With a hydrodynamic brake - it is often Be component of automatic transmission - can heat the transmission oil withdrawn for heating purposes. As a rule, they are Additional brakes as a heat supplier for heating the Passenger cell unsuitable because it is in passenger cars their weight and space requirements are rarely installed.

From the FR-PS 2.133.149 is a liquid-cooled Schei benbremse known for motor vehicles. This is the brake disc formed as part of the wheel hub. Immediately next to the  Brake disc is a heat exchanger. The brake disc, the middle wheel hub area and the condenser connected by a coolant-carrying duct system the.

Furthermore, DE 33 08 061 A1 is a high-performance ticket benbremse known, the brake pads as coolant flow Hollow bodies are formed. The coolant is through a Pumped heat exchanger. The latter gives its warmth when needed fall off as part of a vehicle interior heater.

The present invention is therefore based on the problem to create a device with which by default equipped motor vehicles in addition to the engine coolant circuit other heat sources usable for the passenger compartment heating ge be made.

The problem may a. with the features of the main claim ge solves. It gets thermal energy from the regular driving Generic brake systems decoupled. For this purpose, parts of a Brake disc or a brake drum with cooling fins equipped, being in a housing enveloping the cooling fins Air flows as a heat transfer medium, the at least one Heat exchanger and possibly a filter passes, or wherein the enveloping housing and at least one other Heat exchanger from a liquid heat transfer medium in the Flow through the cooling circuit.

The brake created in conventional friction brakes heat is extracted directly at the point where heat is generated  pelt and with low thermal losses to the plants and me services that need heat.

The brake waste heat is dissipated to the convectional heat Air made usable. To do this, use the brake body Recesses, air blades and / or cooling fins equipped and with a thermally insulating, air-flow Encapsulation. For this are inside disc or Drum brakes particularly suitable. For example, directly brakes lying next to the corresponding axle differential can be encapsulated together with the differential. By the encapsulation flows in the wind. The braking heated air is heated via an air / water Heat exchanger directed.

In a second alternative, the hot brake body radiated heat energy with the help of one of a liquid heat transfer medium flowing through the heat exchanger added.

As a further alternative to using the brake waste heat presented a braking system in which the caliper from Heat transfer medium is flowed through. With this brake system are the brake pads on both sides on one with the wheel to be braked rotating drive disc and are arranged by the brake encircled the saddle at least in some areas. Work in the caliper the brake piston or pistons via a pressure block on the brake coverings. The brake caliper coming into contact with the brake pad area and the pressure block contain a channel or a Ka nalsystem, the part of a heat transfer medium circuit with min is an integrated heat exchanger.

In this solution, the internal brake fluid is circuit stationary with respect to the wheel carrier. Through a thermi  The brake pads can be insulated from the brake disc the latter made of a light metal alloy or a composite fabric are manufactured, with which the accelerated Can significantly reduce wheel mass.

Further details of the object of registration can be found in the subclaims not or only partially cited and the following description of several schematically shown Embodiments:

Fig. 1: brake disc with integrated heat pipe;

Fig. 2: Brake disc with direct cooling by the engine cooling medium.

Fig. 3: brake disc with radiant heat dissipation;

Fig. 4: Brake caliper with direct cooling.

According to FIGS. 1 and 2, a FLÜS Siges heat carrier medium is pumped at least through the animal during driving ro ends brake body via a channel system. The amount of heat generated when braking the motor vehicle in the brake body is transported to a heating body. The radiator is part of a system for heating the passenger compartment.

In brake systems that at least each time the Be can flow through the drive brake with heat transfer medium Brake body, for example the brake disc, through the raised reduction of the maximum temperature from a light weight valley alloy. The material-related Ge weight savings equal the additional weight of the heating circuit partially off again.  

If the heat transfer medium circuit flowing through the brake system run with the cooling circuit of the internal combustion engine ther mixed coupled, for example in long-haul or Uphill the brake body as a heat sink for the engine or Gear oil can be used. The prerequisite for this is that the Brake body at least during its cooling function from the wind be washed around.

Fig. 1 shows part of the circuit of a liquid heat carrier. At least one disc brake is arranged in this circuit.

The disc brake ( 3 ), the brake caliper ( 1 ) and the brake pads ( 2 ) are shown here. The one-piece brake disc ( 3 ) consists of a friction ring ( 11 ) and the disc cup ( 21 ). The friction ring ( 11 ) and part of the disc pot ( 21 ) are hollow. The coherent cavity forms a heat pipe ( 12 ). In the disc pot ( 21 ) is adjacent to the heat pipe ( 12 ), a heat exchanger channel ( 22 ). The separating web ( 23 ) between the heat pipe ( 12 ) and the heat exchanger channel ( 22 ) has to the heat pipe ( 12 ) towards a heating zone ( 15 ) and to the heat exchanger channel ( 22 ) towards a cooling zone ( 26 ).

On the disc pot ( 21 ) in the area of the Wärmetauscherka channel ( 22 ) a two-channel mechanical seal ( 31 ) is arranged. The latter includes an end ring ( 33 ), three bellows ( 34 , 35 , 36 ) with sliding seals ( 37 , 38 , 39 ) and a torsionally rigidly mounted on the ring or caliper carrier (not shown) to the connecting ring ( 32 ). The end ring ( 33 ) is ausgebil det three stages. The connecting ring ( 32 ), which is also stepped three times, lies opposite in the axial direction. The steps of the two rings ( 32 , 33 ) are approximately complementary to each other. Between the gradations, the bellows ( 34 , 35 , 36 ) are arranged concentrically. They are each on their right side from the end ring ( 33 ) attached. At their left, free ends, they carry the sliding seals ( 37 , 38 , 39 ), for example inner sealing seals.

The connecting ring ( 32 ) has an inlet ( 41 ) and a return connection ( 42 ) for the heat transfer medium. The inlet connection ( 41 ) is hydraulically connected via a shut-off valve ( 55 ) to the pressure side of a heat transfer medium pump ( 51 ). Between the heat transfer medium pump ( 51 ) and the shut-off valve ( 55 ), a heat transfer medium store ( 52 ) is arranged. The Rücklaufan circuit ( 42 ) leads via a condenser ( 53 ) into a heating circuit ( 57 ), the end of which on the suction side of the heat transfer medium pump ( 51 ) ends. After the capacitor ( 53 ) is a fe der loaded check valve ( 56 ) is arranged, which blocks in the direction of the capacitor ( 53 ). In the flow direction before the suction side of the heat transfer medium pump ( 51 ) and after the return check valve ( 56 ), a short-circuit line ( 58 ) is installed, which is guided through the condenser ( 53 ). The condenser ( 53 ) is intended to condense any evaporated heat transfer medium so that the pressure in the heating circuit ( 57 ) does not increase too much. Via the short-circuit line ( 58 ) the condenser ( 53 ) receives the heat transfer medium required for the condensation, not overheated.

The heat pipe ( 12 ) in the brake disc ( 3 ) serves as an effective heat exchanger for large heat flows. The frictional heat generated by the operation of the vehicle service brake is transported from the heating zone ( 15 ), mainly fed from the evaporation heat - through the separating web - to the cooling zone ( 26 ). From there it is transferred to a liquid heat transfer medium, for example coolant, engine and / or gear oil or the like.

With increasing vehicle speed, the heat dissipation of the heat pipe ( 12 ) increases, since the increasing centrifugal force supports the circulation of the heat transfer medium. The heat transfer medium which evaporates at least partially at the cooling zone ( 26 ) is returned to the liquid phase in a condenser ( 53 ). The downstream of the pump ( 51 ) heat transfer medium storage ( 52 ) serves to buffer the pressure and volume change of the heat transfer medium. In addition, the Wärmeträgermittelspei cher ( 52 ) ensures sufficient replenishment of heat transfer medium to the brake body when large amounts of heat occur in a short space of time.

To make better use of the frictional heat in cold weather, the brake system can be provided with a windproof capsule ( 45 ) in the area of the brake disc ( 3 ) or brake drum. The capsule ( 45 ) can consist of a thermally insulating material, or be coated with such a material.

In order to enable conventional cooling of the braking system by wind during the warmer seasons, the capsule ( 45 ) can be provided with at least one closable opening, for example.

If the brake is only cooled by the airstream and the heat transfer medium pump ( 51 ) in the heating circuit is switched off, the brake disc must withstand the vapor pressure generated during braking at maximum nominal temperature. If the steam pressure is too high, the evaporated heat transfer medium escapes via the check valve ( 56 ) when the shut-off valve ( 55 ) is closed. The mechanical seals ( 37 , 38 , 39 ) are temperature-resistant. In addition, the seals ( 37 , 38 , 39 ) can be thermally decoupled from the end ring ( 33 ) by means of special bellows ( 34 , 35 , 36 ).

Fig. 2 shows a heating circuit comparable to Fig. 1. However, the heat transfer medium is passed directly through a channel system ( 13 ) arranged in the friction ring ( 11 ) of the brake disc ( 3 ). Due to the direct contact of the heat transfer medium with the friction ring ( 11 ) and the omission of a heat transfer point, a stronger cooling of the brake body can be achieved compared to the solution presented in FIG. 1.

If necessary, the brake disc ( 3 ) can be used as a pump by a sectionally radial design of the channel system ( 13 ), so that the pump ( 51 ) can be dispensed with.

Fig. 3 shows a disc brake with a two-part heat exchanger ( 61 , 62 ), which absorb and derive the heat radiation emitted by the brake disc ( 3 ) in part. For this purpose, the brake disc ( 3 ) is ribbed, for example in the inner region of the friction ring ( 11 ). This area forms the cooling zone. The friction ring ribs ( 63 ) are concentric rings which are arranged on both sides of the friction ring ( 11 ). Annular heat exchanger fins ( 64 ) also protrude into the annular cavities between the friction ring fins ( 63 ). The heat exchanger ribs ( 64 ) arranged on the wheel carrier or the brake caliper carrier do not touch the friction ring ribs. To increase the heat transfer capacity, the friction ring ( 63 ) and heat exchanger fins ( 64 ) can be provided with a structured surface. The structure can e.g. B. tooth-shaped or wave-shaped to verbes to the portion of the convective heat dissipation by an increased shear flow between the ribs.

In addition, the brake disc ( 3 ) is equipped with a heat pipe ( 12 ). The heat pipe ( 12 ) is used to transport heat within the friction ring ( 11 ) from the hot braking zone to the cooling zone.

In this embodiment, the heat is transferred contact-free from the rotating brake body ( 3 ) to the stationary heat exchanger ( 61 , 62 ). Because of the heat extraction there are no sealing problems and hardly any friction losses.

In Fig. 4, a construction is shown in which the heat transfer medium flows through the non-rotating brake caliper. In this construction, a driver plate ( 71 ) with insulating sleeves ( 72 ) and a brake pad carrier ( 81 ) with driver pins ( 82 ) form a functional unit, which is called the brake disc below. The two brake pad carriers ( 81 ) are flat, co-rotating rings which are connected to one another via driver pins ( 82 ). You sit cross-slidably in the insulating sleeves ( 72 ) to compensate for the movement of the brake piston or the ben ( 93 ) and a lining wear. If necessary, the brake pad carrier ( 81 ), for. B. by mechanical springs or friction clamps, mechanically centered with respect to the driver plate ( 71 ) and damped against vibration.

A slight play between the driving pins ( 82 ) and the insulating sleeves ( 72 ) supporting them also enables radial movement of the brake lining carrier ( 81 ) relative to the driving disk ( 71 ), so that the thermal expansion occurring during braking does not lead to tension.

The brake pad carriers ( 81 ) have a low thermal conductivity and a low heat storage capacity. They are thermally separated from the drive plate ( 71 ) by the pins ( 82 ) and the insulating sleeves ( 72 ). The latter can be made of a light metal alloy or of a material, for example a composite material, with low temperature resistance.

The non-rotating part of the wheel brake system includes a brake caliper ( 91 ), a pressure block ( 92 ) and a Bremskol ben ( 93 ). At least the caliper area, which comes into contact with the brake pad during braking, and the pressure block ( 92 ) consist of a material with high thermal conductivity and high strength. The material may also have a low specific weight. In the corre sponding caliper area and the pressure block ( 92 ) Ka channels ( 96 , 97 ) are embedded, which are flushed through at least during the braking process by a heat transfer medium. The channels ( 96 , 97 ) are connected in series, for example.

The brake caliper ( 91 ) and the pressure block ( 92 ) can also be ring-shaped, so that the friction surfaces abut the entire brake pad surface when braking. This variant results in a large heat transfer area, good heat dissipation, symmetrical brake disc loading and a reduction in braking forces.

The pressure block ( 92 ) is stored in the brake caliper ( 91 ) against rotation. He is for example by pins, not shown, or a profile in the brake caliper ( 91 ) prevented from rotating. In addition, it is mechanically coupled with the brake piston (s) ( 93 ) in such a way that it follows the return stroke of the brake piston ( 93 ) in order to produce the necessary clearance.

Reference list

1

Brake caliper

2nd

Brake pads

3rd

Brake disc, brake body

11

Friction ring

12th

Heat pipe

13

Channel system (

Fig.

2nd

)

15

Heating zone

21

Disc pot

22

Heat exchanger duct

23

Separator

26

Cooling zone

31

Mechanical seal

32

Connecting ring

33

End ring

34

,

35

,

36

Pipes, bellows

37

,

38

,

39

Sliding seals

41

Inlet connection

42

Return connection

45

capsule

51

Heat transfer medium pump

52

Heat transfer medium storage

53

capacitor

55

Shut-off valve

56

check valve

57

Heating circuit

58

Short-circuit line

61

,

62

Heat exchanger

63

Friction ring ribs

64

Heat exchanger fins

71

Drive plate

72

Insulating sleeves

81

Brake pad carrier

82

Driving pins

83

Brake pads

91

Brake caliper

92

Contact block

93

Brake piston

94

Pressure line

96

Channel system in (

91

)

97

Channel system in (

92

)

Claims (4)

1. Apparatus for decoupling thermal energy from vehicle braking systems for heating purposes for the passenger compartment, parts of the service brakes arranged in the wheel or axle area and at least one heat exchanger being flowed through by a cooling medium, characterized in that parts of the brake disc ( 3 ) or the brake drum with cooling fins (63) are provided, wherein in a the Kühlrip pen (63) enveloping housing flows air that passes through at least one further heat exchanger, or wherein the encapsulating Ge housing and at least one further heat exchanger are traversed by a FLÜS sigen heat transfer medium in the cooling circuit . 2. Device according to claim 1, characterized in that in the brake disc ( 3 ) or in the brake drum, a heat pipe ( 12 ) is integrated. 3. Device according to claim 1, characterized in that in the brake disc ( 3 ) or in the brake drum, the heat pipe ( 12 ) adjacent to a heat exchanger ( 61 , 62 ). 4. Apparatus for decoupling thermal energy from vehicle braking brake systems for heating purposes for the passenger compartment, with at least one brake piston acting on the brake pads in the brake caliper via a pressure block, the brake caliper area coming into contact with the brake pad and the pressure block including a channel or a channel system and wherein the channel or the channel system is part of a heat transfer medium circuit with at least one integrated heat exchanger, characterized in that

• 1. that the brake pads ( 83 ) are arranged on both sides on a rotating with the wheel to be braked drive plate ( 71 ) and are encompassed by a brake caliper ( 91 ) at least in some areas
• 2. that the brake pads ( 83 ) are thermally insulated from the drive plate ( 71 ) and
• 3. that the brake pads ( 83 ) sit on a brake pad carrier ( 81 ) which is slidably mounted in the driver plate ( 71 ) with the aid of driver pins ( 82 ).