Patent Description:
Before the very first activation of an automotive engine, for example of an internal combustion engine, it can generally not be excluded that small amounts of moulding sand and of other production-caused particles still are present in the cooling channels of the engine block. The liquid coolant for cooling the engine is circulated by a mechanical or by an electrical coolant pump which is generally sensible for solid particles floating in the liquid coolant.

Generally, a simple particle filter could be provided in the engine cooling circuit to protect the coolant pump. The particle filter is only necessary at the start of the engine's lifetime to collect the solid particles but causes a relevant flow resistance over the complete lifetime of the engine.

<CIT> and <CIT> disclose separators using a vortex arrangement for separation of particles or of gas bubbles wherein the flow direction of the liquid is turned by <NUM> ° which causes a considerable flow resistance.

It is an object of the invention to provide an automotive cooling circuit particle separator with a negligible flow resistance for extracting production-caused particles from the coolant flow.

This object is solved with an automotive cooling circuit particle separator with the features of claim <NUM>.

The automotive cooling circuit particle separator is provided with an inflexible linear coolant inlet duct, a linear vortex means, a linear separation tube and a particle trap reservoir. The particle separator is following a linear concept with a closed particle trap reservoir so that the engine cooling circuit is a fluidically closed system which can be pressurized. The particle trap reservoir has a relatively small total volume and is dimensioned to accumulate all the production-caused particles from the coolant flow, and has a typical a volume of less than <NUM>, preferably of less than <NUM>.

The automotive cooling circuit particle separator according to the invention can be a discrete part of the cooling circuit or can be an integral part of the coolant pump.

The vortex means comprises at least one vortex vane for causing the incoming coolant flow to rotate so that the coolant flow is forced into a screw-like flow pattern. A linear separation tube with a circular front opening edge is arranged coaxially with and downstream of the vortex means. The particle trap reservoir is provided radially outside of the separation tube and fluidically downstream of the front opening edge of the separation tube.

As soon as the liquid coolant is pumped in the right direction within the engine cooling circuit, the vortex means generates within the liquid coolant current a screw-like vortex flow pattern. This causes the solid particles, as for example moulding sand having a higher specific weight than the liquid coolant to the radial outside of the liquid coolant flow because of centrifugal force. The solid particles pass by the circular front opening edge of the separation tube at its outside and move forward with their individual impulses to the downstream particle trap reservoir. The particle trap reservoir is accessible through one or more openings and is a closed reservoir so that no significant liquid flow is present within the particle trap reservoir.

The particle trap reservoir is provided radially outside of the separation tube so that the liquid coolant current flowing through the separation tube provides a linear general flow direction between the inlet and the outlet of the particle separator. As a result, the flow resistance of the cooling circuit particle separator is very small so that providing the automotive cooling circuit particle separator in the combustion engine cooling circuit does not significantly increase the lifetime power consumption of the coolant pump.

The separating rate of the automotive cooling circuit particle separator needn't be very high because the coolant is flowing in a closed circuit so that, even with a relatively low separating rate per cycle, the production-caused particles are separated after less than one hour, in particular even after less than <NUM> minutes, of an initial coolant pump activity. The accumulated particles remain in the particle trap reservoir for the lifetime of the engine.

Preferably, the inlet duct is provided with a hydraulic linearization means for axial linearization of the incoming coolant flow. The linearization means can be in particular realized as static longitudinal blades or as a blade structure. The hydraulic linearization means makes sure that the incoming coolant flow is perfectly linear in longitudinal direction of the cooling circuit particle separator right before the liquid coolant flow hits the vortex means. As a result, the separating effect as well as the flow resistance of the cooling circuit particle separator are perfectly defined and reproducible under different circumstances with respect to the flow direction components of the incoming coolant liquid flow entering the cooling circuit particle separator. This allows to design the cooling circuit particle separator with a very low flow resistance because no substantial functionality reserve for a non-perfect and disadvantageous mounting situation needs to be included in the design.

Preferably, a radial particle trap inlet opening is provided downstream of the vortex means, whereas the particle trap reservoir is provided downstream of the particle trap inlet opening. Since the liquid coolant flow downstream of the vortex means has a rotational component, the particles have a radial acceleration and movement component so that the particles can radially migrate through the particle trap inlet opening into the particle trap reservoir downstream of the particle trap inlet opening.

Preferably, the particle trap reservoir is realized as a ring cavity provided radially outside of the separation tube and at least in part longitudinally overlapping, when seen in radial direction, with the separation tube. The particle trap reservoir ring cavity can be arranged, for example, directly outside of the cylindrical vortex means tube housing the vortex vanes. The particle trap reservoir ring cavity does not increase the total longitudinal length of the automotive cooling circuit particle separator.

Preferably, the particle trap reservoir ring cavity is provided with a dividing wall blocking a rotational movement of the liquid coolant within the particle trap reservoir ring cavity so that the liquid coolant can not rotate within the ring cavity. The dividing wall is preferably substantially arranged and orientated in a longitudinal direction. Since the liquid coolant within the particle trap reservoir ring cavity does not significantly move or rotate, the accumulated particles reliably remain within the particle trap reservoir for the lifetime of the engine.

Preferably, the linear axis of the cooling circuit particle separator is lying in a horizontal plane when the cooling circuit particle separator is mounted within the automotive device. The hydraulic concept and performance of the cooling circuit particle separator is designed for a horizontal mounting orientation of the particle separator. This allows to design the cooling circuit particle separator precisely for a substantially horizontal orientation of the longitudinal axis so that the flow resistance is optimized.

Preferably, a deaeration opening is provided in a vortex part wall between the particle trap reservoir and the vortex flow passage. This aspect can be an independent inventive aspect used in an automotive cooling circuit particle separator provided with a vortex means and with a closed particle trap reservoir.

The circulating liquid coolant can have at least a small volume of air bubbles which could be collected in the particle trap reservoir so that, without a deaeration opening, the particle trap reservoir finally could completely be filled with air. The deaeration opening is provided at a high point or at the highest point of the particle trap reservoir and fluidically connects the particle trap reservoir with the main liquid coolant current upstream of the circular front opening of the separation tube. The fluid located at the deaeration opening and potentially containing air or air bubbles is sucked back into the main liquid coolant current by, for example, a Venturi-effect so that a very constant, small and slowly fluid flow from the particle trap reservoir back into the main liquid coolant current is generated. This fluid flow is that slowly that the solid particles are not carried with this slowly flow through the deaeration opening back into the main current but remain in the particle trap reservoir and sink to the bottom of the particle trap reservoir due to gravity.

More preferably, the deaeration opening is located axially upstream of the separation tube where the relative flow speed of the main coolant liquid coolant flow is relatively high so that the Venturi effect is relatively strong.

Preferably, the radial particle trap inlet opening is located at the vertical top of the vortex part wall separating the particle trap reservoir and the vortex flow passage. The trap inlet opening is therefore located at the vertically highest point of the main liquid coolant flow so that the solid particles, after having entered the particle trap reservoir through the inlet opening, sink down to the bottom of the particle trap reservoir. Since no significant liquid flow is possible within the particle trap reservoir, the accumulated solid particles reliably remain in the particle trap reservoir for the lifetime of the engine.

Preferably, a ring-like guiding wall is provided axially between the particle trap inlet opening edge and the particle trap reservoir ring cavity arranged axially beyond the guiding wall. More preferably, the guiding wall avoids a direct linear liquid coolant current from the particle trap inlet opening to the deaeration opening so that the separation of the air bubbles from the solid particles is improved significantly. In addition, the guiding wall causes an initial circumferential flow direction of the incoming and the parallel outgoing liquid coolant flow so that the solid particles are accelerated downwardly before the partial liquid coolant flow turns upwardly and back to the particle trap inlet opening. This effect increases the separation rate of the cooling circuit particle separator.

According to an independent invention aspect, the automotive cooling circuit particle separator is made of three different pieces, namely an inlet duct part defining the inlet duct, a separation tube part defining the separation tube and a separate vortex part defining the vortex means. The vortex part preferably is form fitted with the inlet duct part and/or the separation tube part. The automotive cooling circuit particle separator is based on a modular concept, wherein in particular the vortex part can be selected individually for every different application, whereas the other two parts, namely the inlet duct part and the separation tube part, could be used for many different applications and installation situations. Since the cooling circuit particle separator should not cause any relevant flow resistance, the hydrodynamic characteristics of the vortex part and, if relevant, of the separation tube part should be perfectly adapted for the hydrodynamic situation of the specific application. The modular concept of the cooling circuit particle separator allows to use identical parts for inlet duct part and, if given, the separation tube part, for different cooling circuit particle separator models so that production costs can be minimized.

Preferably, the separate vortex part is made of another plastic material then the inlet duct part and the separation tube part. Preferably, the separate vortex part is made of a harder and therefore more expensive plastic material than the other parts. The vortex vane(s) is/are exposed to the somehow abrasive liquid coolant flow. Using a relatively hard (plastic) material allows to provide very thin vortex vanes so that the flow resistance can be minimized.

Preferably, the plastic inlet duct part and the plastic separation tube part are joined together by friction welding, whereas the separate vortex part is hold and fixed preferably only by form-fitting. The friction welding can, for example, be realized by simply rotating the generally circular inlet duct part and the generally circular separation tube part relative to each other so that the assembly of the cooling circuit particle separator is provided simple and cost-effectively. The friction welding includes ultrasonic welding.

According to another independent inventive aspect, an automotive cooling circuit comprises an automotive engine, a coolant pump for pumping the coolant within the cooling circuit and an automotive cooling circuit particle separator, preferably based on a linear concept. The particle separator is arranged in the lowest third of the total vertical extent of the complete cooling circuit. More preferably, the cooling particle separator is located downstream of the vertically lowest location of the cooling circuit.

Generally, the solid particles tend to accumulate at the lowest region of the complete cooling circuit because of gravitation. If the flow velocity of the coolant in the cooling circuit is relatively low, some of the solid particles could be too heavy to be carried away with the liquid coolant flow to a vertically substantially higher position of the coolant circuit. If the particle separator is arranged right after the lowest region of the cooling circuit, the particles accumulated at the lowest region do not need the to be transported to a higher point of the circuit, and are separated immediately by the cooling circuit particle separator right after the first start of the coolant pump.

According to an independent inventive aspect, the cooling circuit particle separator comprises a vortex means causing a rotation of the liquid coolant current. The rotational direction of the rotational component of the liquid coolant current flowing through the particle separator outlet is identical with the rotational direction of the pump rotor of the coolant pump. The coolant pump <NUM> is provided downstream of the cooling circuit particle separator, and the distance between the particle separator outlet and the coolant pump rotor <NUM> is less than <NUM>.

The invention is described with reference to the enclosed drawings, wherein.

<FIG> shows a typical automotive cooling circuit <NUM> comprising an internal combustion engine <NUM> as a traction engine, an electric or mechanical coolant pump <NUM> and an automotive cooling circuit particle separator <NUM> downstream of the engine <NUM> and upstream of the coolant pump <NUM>. <FIG> shows a vertical plane YX, wherein Y is the vertical axis and X is an axial horizontal axis. As a schematically is indicated in <FIG>, the cooling circuit particle separator <NUM> is located in the lowest third of the total vertical extent YC of the complete cooling <NUM> circuit. Preferably, the cooling circuit particle separator <NUM> is located downstream of right after the lowest point of the cooling circuit <NUM>. The linear axis <NUM> of the cooling circuit particle separator <NUM> is lying in a horizontal plane XZ.

The cooling circuit particle separator <NUM> is based on a linear concept which means that the particle separator inlet <NUM> and the particle separator outlet <NUM> are perfectly in-line with each other having the same longitudinal axis <NUM>. The cooling circuit particle separator <NUM> is substantially defined by four functional elements, namely an inflexible linear coolant inlet duct <NUM>, a linear vortex means <NUM>, a linear separation tube <NUM> with a circular front opening edge <NUM> and a particle trap reservoir <NUM>.

The inlet duct <NUM> is provided with a hydraulic linearization means <NUM> for axially linearization of the coolant flow entering the cooling circuit particle separator <NUM> through the particle separator inlet <NUM>. The linearization means <NUM> is realized by several static longitudinal linearization blades <NUM>. Alternatively, a grid-like or honeycomb-like blade structure can be provided as a linearization means. The linearization means <NUM> causes the incoming liquid coolant flow to hit the downstream linear vortex means <NUM> always precisely in axial direction parallel to the longitudinal axis <NUM>. The inlet duct <NUM> housing is defined by an inlet duct wall <NUM> having an upstream cylindrical part <NUM>' with the linearization means <NUM> and a downstream conical part <NUM>".

The linear vortex means <NUM> is arranged coaxially with and downstream of the inlet duct <NUM>, and is defined by a cylindrical vortex part wall <NUM>, by a central displacement core <NUM> and by several vortex vanes <NUM> mechanically connecting the displacement core <NUM> and the surrounding cylindrical vortex part wall <NUM>. The linear vortex means <NUM> generates a counter-clock-wise rotation of the liquid coolant current, seen from the particle separator inlet <NUM>. The linear liquid coolant flow is thereby changed into a vortex-like flow pattern.

The linear separation tube <NUM> is defined by a substantially cylindrical separation tube wall <NUM> arranged downstream of the vortex means <NUM> and has an inner diameter similar to the inner diameter of the inlet duct cylindrical part <NUM>'. The liquid coolant flows through the circular front opening edge <NUM> of the separation tube <NUM> to the cooling circuit particle separator outlet <NUM>. The downstream part <NUM>' of the separation tube wall <NUM> is provided with a hydraulic guiding means <NUM> guiding the liquid coolant current, for example defining a slight rotational flow component within the liquid coolant current. The hydraulic guiding means <NUM> is realized by several longitudinal guiding blades <NUM>.

The rotational component of the liquid coolant current leaving the cooling circuit particle separator <NUM> through the outlet <NUM> is identical with the rotational direction of the pump rotor <NUM> of the coolant pump <NUM>. The coolant pump <NUM> is provided downstream of the coolant cooling circuit particle separator <NUM>, and the distance between the particle separator outlet <NUM> and the coolant pump rotor <NUM> is about <NUM> but can be even less than <NUM>.

A particle trap reservoir <NUM> is provided radially outside of the separation tube <NUM> and of the vortex part wall <NUM>. The particle trap reservoir <NUM> is substantially a cylindrical ring cavity <NUM>' defined at the inside by the cylindrical vortex part wall <NUM> and at the outside by a cylindrical housing wall <NUM> being integral with the inlet duct wall <NUM>.

The ring cavity <NUM>' of the particle trap reservoir <NUM> is accessible through a radial particle trap inlet opening <NUM> provided at the top of the cylindrical vortex part wall <NUM>. A deaeration opening <NUM> is provided in a vertical top location of the vortex part wall <NUM>. The deaeration opening <NUM> is, seen in longitudinal direction, located between the separation tube opening edge <NUM> and the vortex blades <NUM>, and fluidically connects the particle trap reservoir <NUM> and the vortex flow passage <NUM> between the vortex blades <NUM> and the separation tube opening edge <NUM>.

A ring-like guiding wall <NUM> is provided at the front edge of the particle trap inlet opening <NUM> and blocks a direct axial flow between the particle trap inlet opening <NUM> and the deaeration opening <NUM>.

An axial longitudinal dividing wall <NUM> is provided within the trap reservoir ring cavity <NUM>' for blocking any rotational movement of the coolant in the particle trap reservoir ring cavity <NUM>'. The dividing wall <NUM> is provided integrally with the vortex part wall <NUM>, and is, seen in vertical cross-section, located not in the middle but in <NUM>° so that the rotational component of the incoming particles causes the particles to fill up the <NUM>° space.

As shown in <FIG>, the cooling circuit particle separator <NUM> has a modular concept, and is assembled from three parts, namely a plastic inlet duct part <NUM> defining the inlet duct <NUM>, a plastic separation tube part <NUM> defining the separation tube <NUM> and a separate plastic vortex part <NUM> defining the vortex means <NUM>. The vortex part <NUM> is form-fitting assembled with the inlet duct part <NUM> and the separation tube part <NUM>. The vortex part <NUM> is made of another and harder plastic material, for example made of Polyphenylensulfid, than the inlet duct part <NUM> and the separation tube part <NUM> which can be made of Polyamid <NUM>.

Claim 1:
An automotive cooling circuit particle separator (<NUM>) for an automotive engine cooling circuit (<NUM>) with a circulating liquid coolant, comprising
an inflexible linear coolant inlet duct (<NUM>),
a linear vortex means (<NUM>) arranged coaxially with and downstream of the inlet duct (<NUM>), the vortex means (<NUM>) comprising at least one vortex vane (<NUM>) for rotating the incoming coolant flow,
a linear separation tube (<NUM>) with a circular front opening edge (<NUM>) arranged coaxially with and downstream of the vortex means (<NUM>), and
a particle trap reservoir (<NUM>) radially outside of the separation tube (<NUM>) and downstream of the front opening edge (<NUM>) of the separation tube (<NUM>).