FI129340B

FI129340B - Method and tools for cleaning interior surfaces of a combustion engine

Info

Publication number: FI129340B
Application number: FI20206270A
Authority: FI
Inventors: Jussi Tukiainen
Original assignee: Autotuksa Oy
Priority date: 2020-12-09
Filing date: 2020-12-09
Publication date: 2021-12-15
Also published as: FI20206270A1; WO2022123115A1

Abstract

The present disclosure describes a washing device for cleaning an interior of an engine block of an internal combustion engine. The present disclosure further discloses a method utilising the washing device. The washing device (30) comprises an engine interface (32.2) configured to be attached on an oil pan mounting surface (14.2) of the engine block. The engine interface (32.2) is configured to seal the interior of the engine block into an essentially closed volume that can be filled with washing liquid. The washing device (30) further comprises a heater unit (36) for heating the washing liquid and an ultrasound unit (38) comprising at least one ultrasound transducer. The ultrasound unit (38) is configured to induce ultrasound emission to washing liquid in the closed volume.

Description

METHOD AND TOOLS FOR CLEANING INTERIOR SURFACES OF A COMBUSTION ENGINE

FIELD The invention relates to maintenance and repair of internal combustion engines, and in particular, to cleaning interior surfaces of an engine block.

BACKGROUND INFORMATION Regular maintenance of a vehicle that has an internal combustion engine (such as a gasoline engine or a diesel engine) is crucial for reliable operation of the vehicle. For example, combustion residues and engine sludge (mixture of engine oil that has been oxidized, and dirt and soot that are in the air that the engine takes in for combustion) accumulate on surfaces of internal parts of the engine over time. This may significantly reduce the efficiency of the engine. The reduced efficiency may manifest itself as increased oil consumption, for example.

A thorough cleaning of the engine without disassembling it may be very difficult. Specifically, cleaning of close-fitting internal engine parts, such as the piston and its rings in a cylinder, is typically impossible without an extensive engine disassembly. However, disassembling an engine block (and assembling it back again) to manually check (and replace, when needed) engine parts is a cumbersome procedure. o BRIEF DISCLOSURE O An object of the present disclosure is to provide a method for cleaning a N 25 combustion engine and tools for said method so as to alleviate the above a disadvantages. The object of the disclosure is achieved by a method and tools which S are characterized by what is stated in the independent claims. The preferred E embodiments of the disclosure are disclosed in the dependent claims. o O 30 A cleaning method according to the present disclosure is based on the use of N ultrasound in a cleaning phase of the method. In the method, an oil pan of the N engine is removed, and a washing device according to the present disclosure is attached in place of the oil pan. The interior volume of the engine block is then filled with a washing liquid, and the washing device is used to heat the washing liquid and generates ultrasound emissions to it. The cleaning phase cleans the interior surfaces very thoroughly, without a need of extensive disassembly of the engine block.

In addition to the washing device, a method according to the present disclosure may utilise other tools, such as a piston position indicator according to the present disclosure and an oil pump assembly according to the present disclosure. The indicator makes preparation for the cleaning phase easier, while the oil pump assembly can be used for providing an oil film to bearing surfaces of the engine block in a finalising phase after the cleaning phase.

BRIEF DESCRIPTION OF THE DRAWINGS In the following the invention will be described in greater detail by means of — preferred embodiments with reference to the attached drawings, in which Figure 1 shows a simplified cross-sectional diagram of an internal combustion engine; Figure 2 shows a simplified cross-sectional diagram of a piston position indicator according to the present disclosure; Figure 3 shows a simplified cross-sectional diagram of an engine block to which a washing device according to the present disclosure has been attached; N Figure 4 shows a simplified flow diagram of an oil circulation system of an engine N block of an internal combustion engine; and 3 Figure 5 shows a simplified cross-sectional diagram of an oil pump adapter E 30 according to the present disclosure.

S

S DETAILED DISCLOSURE N The present disclosure describes a method for cleaning interior surfaces and engine parts of an engine block of an internal combustion engine, such as a gasoline engine ora diesel engine. Figure 1 shows a simplified cross-sectional diagram of an internal combustion engine 10. In Figure 1, a piston 11 is arranged within a cylinder 12 and a crankshaft 13 is in a crankcase 14. A connecting rod 15 connects the piston 11 to the crankshaft 13. The piston 11 has piston rings 16, including an oil ring 16.1. The crankcase 14 comprises an oil pan 14.1 that is detachable. In the method, the oil pan 14.1 is removed, and a washing device according to the present disclosureis attached in place of the oil pan. The interior volume of the engine block is filled with a washing liquid, and the washing device may be used to heat the washing liquid and generate ultrasound emissions to it. The method can be roughly divided into three phases: a preparation phase, a cleaning phase, and a finalising phase. These three phases are discussed in more detail below. While the present disclosure discusses using a washing device according to the present disclosure for cleaning an engine block, the washing device may also be used for cleaning other things, such as automatic transmission of a vehicle, for example.

The preparation phase may start by removing spark plugs (or glow plugs). It may then be desirable to check the conditions of the pistons (by performing a leak-down test). If high leakage values are measured, the cleaning process may be cancelled. High leakage values imply that the engine has suffered a mechanical failure. As the cleaning method according to the present disclosure does not fix such mechanical failures, continuing with the method may not be reasonable.

However, if the measured leakage values are within a permissible range, the preparation phase may be continued by preparing the oil circulation system for the washing phase. The preparing of the oil circulation system comprises at least the — steps of draining motor oil from the engine and removing the oil pan, thereby o exposing an oil pan mounting surface and the interior of the crankcase and the S cylinders. The oil filter and the oil filler cap are preferably also removed in the N preparation phase. S 30 Further, the pistons are preferably aligned to the same level with respect to each E other for a reason that will become apparent later in this disclosure. Aligning the o pistons may comprise mounting a piston position indicator to a spark plug hole (or N glow plug hole) of a predetermined cylinder (e.g. the first cylinder) and rotating N the crankshaft so that the indicator indicates that the piston is at a desired position N 35 — (Le.in a position where all pistons are at the same level in a piston group). Figure 2 shows an exemplary piston position indicator according to the present disclosure. Some features of the piston position indicator of Figure 2 are discussed in more detail later in this disclosure. In addition, where applicable, oil lines of any other parts (e.g. an oil cooler and a turbocharger) may be disconnected from the engine block and open inlets and outlets of said oil lines may be plugged. After the preparation phase, the engine is ready for a cleaning phase according to the present disclosure. In the cleaning phase, a washing device according to the present disclosure is attached to the exposed oil pan mounting surface of the engine block, thereby sealing the interior of the engine block into an essentially closed, water-tight volume. Figure 3 shows a simplified cross-sectional diagram of an engine block 10 to which an exemplary embodiment of a washing device 30 according to the present disclosure been attached. Some features of the washing — device 30 of Figure 3 discussed in more detail later in this disclosure. Once the washing device has been attached to the engine block, the interior of the engine block can be filled with a washing liguid. The washing liguid is preferably alkaline. The interior of the engine block may be filled a washing liguid to a level where all pistons are completely immersed in the washing liquid. Thus, the liquid level may reach the combustion chamber. In Figure 3, the washing liquid is at level L, thus reaching the combustion chamber 12.1. However, the liquid level should preferably not reach the valve gear. For this reason, the aligning of the pistons is preferable. The lowest liquid level completely immersing all pistons can be achieved when the pistons all are at the same height in the cylinders. In Figure 3, o the liguid level L is below the valve gear 18.

S eu When the interior of the engine block is filled with washing liguid, ultrasound a emissions may be generated to the liguid. For this purpose, the washing device © 30 comprises an ultrasound unit. In order to achieve better cleaning results, the E washing liguid may be heated prior to and/or during the ultrasound phase. o Therefore, the washing device according to the present disclosure may also N comprise means for heating the washing liguid. In Figure 3, the washing device 30 N comprises an ultrasound unit 38 and a heater unit 36. Ultrasound emissions may N 35 be generated for a predetermined time. After that, the washing liquid may be drained, the washing device may be removed, and the engine block may be dried.

When the washing device is removed, the interior of the engine block is again exposed to the ambient environment. Thus, a further advantage of heating the washing liquid (and, as a result, the engine parts) is that any remaining washing liquid evaporates quickly from surfaces of the engine parts. 5 After the cleaning phase, the interior surfaces of the engine block and the surfaces engine part (including surfaces of the pistons, the connecting rods, and the crankshaft) are thoroughly cleaned. However, this also means thatbearing surfaces in the engine block no longer have an oil film acting as lubricant. Therefore, the engine cannot be started. To bring the engine to an operable state, a finalizing phase of the cleaning method may be performed. The finalising phase may comprise at least the step of generating an oil film to the bearing surfaces without moving the engine parts (i.e. without the crankshaft turning). This can be accomplished by attaching the oil pan, adding motor oil to the engine block, and causing an oil circulation with an external oil pump. Some features of an embodiment of generating the oil circulation are discussed in relation to Figures 4 and 5 later in this disclosure. Some penetrating oil (e.g. WD-40) may also be sprayed in all cylinders via the spark plug (or glow plug) holes.

When a sufficient oil film has been generated to the bearing surfaces, final steps of the finalising phase can be taken to reassembly the engine. These final steps may include draining the motor oil once again, removing the external pump and any plugs added during the preparation phase, reconnecting any disconnected oil lines, installing a new oil filter and new spark plugs (or glow plugs), and adding new motor oil, for example.

N After the finalising phase, the bearing surfaces in the engine are sufficiently

N eu lubricated and the engine can be started. To test the engine, it may be started and a let run at idle for a while (e.g. 10 minutes) to ensure that all surfaces in the engine © 30 — are sufficiently lubricated. After that, a test drive may be performed, for example.

E o The above paragraphs have discussed steps taken during a preparation phase, a N cleaning phase, and a finalising phase of a cleaning method according to the present N disclosure. In the following, some specific aspects and embodiments of tools and N 35 accessories related to the method (and an arrangement implementing the method) are discussed in more detail.

As discussed earlier, the preparation phase includes a step of aligning the pistons. Figure 2 shows a simplified cross-sectional diagram of a piston position indicator according to the present disclosure. The indicator 20 in Figure 2 comprises a probe rod 22 and a sleeve 24 around the rod 22. The probe rod 22 can slide freely inside the sleeve 24. The sleeve 24 has threading 24.1 that corresponding the threading of a spark plug so that the indicator 20 can be screwed to a spark plug hole in the engine block. During use, one end of the probe rod 22 rests on top of the piston crown. As the piston is being moved, the probe rod 22 moves along with it. The — position indicator 20 is provided with markings showing when the piston is at a desired position in the cylinder. For example, a notch in the probe rod 22 may indicate the desired position. Each motor type/variant may have its own piston position indicator. The preparation phase of a cleaning method according to the present disclosure is not limited only to use of an indicator tool as described in Figure 2. Any other tool capable of giving an indication of the pistons being at the same level (without needing to open the engine further) can be used. Further, while the alignment of the pistons is preferable, the cleaning method may be performed without it in some embodiments.

= Next, some features of an exemplary washing device according to the present disclosure are discussed in more detail. As mentioned earlier, the washing device is attached in place of the oil pan. For this purpose, the washing device has an engine interface configured to be attached on an oil pan mounting surface of the engine block. The engine interface is adapted to seal the interior of the engine block into an essentially closed volume that can be filled with washing liquid.

N In some embodiments, the washing device comprises a base unit and an adapter N unit that forms the engine interface connecting the base unit to the engine block. a For example, in Figure 3, the washing device comprises an adapter unit 32 has an © 30 engine interface 32.2 thatattaches a base unit 34 of the washing device 30 to an oil E pan mounting surface 14.2 of a crankcase 14 of the engine block. The adapter unit o 32 forms a hollow tube or funnel with a wide diameter (e.g. tens of centimetres) N between the base unit 34 and the engine block. This allows the ultrasound N emissions from the base unit 34 to reach the engine parts without significant N 35 obstructions. The shape and dimensions of the engine interface may vary depending on the type and variant of the engine being cleaned. However, the interface for the base unit may always remain the same. In this manner, the same base unit may be used with different types and variants of combustion engines. The adapter unit is preferably detachable from the base unit so that different adapter units can be used with the base unit. In some embodiments, however, the adapter unitmay also be integrated to the base unit. A base unit of a washing device according to the present disclosure may be in the form of a water-proof container with an opening on top. The opening corresponds with the shape and size of the adapter unit. In Figure 3, the base unit 34 is in the form of a rectangular, hollow box. The top surface of the box has a large opening through which ultrasonic emission pass through. In some embodiments, the top surface (or the bottom surface) is in the form of a removable lid. In this manner, the interior of the base unit 34 can be maintained more easily. As shown in Figure 3, the interior spaces of the base unit 34 and the adapter unit 32, together with the interior spaces of the engine block (including interior spaces of the cylinder 12 and the crankcase 14) form a united, continuous volume. As discussed earlier, this volume is supplied with washing liquid during the cleaning process and filled up to level where the pistons are completely immersed in the liquid. The amount of washing liquid may be around 25 to 30 litres, for example. In order to be able to monitor the liquid level during the filling, the washing liquid may be supplied via transparent pipe or hose. In Figure 3, the washing liquid is supplied with a transparent fill pipe 34.2. As the liquid level is at the same height in the fill pipe as inside the engine block, the progress of the filling can be easily monitored. The fill pipe or hose may be connected to the base unit, for example. In o addition, the base unit may further comprise a drain outlet for drain the washing S liguid at the end of the cleaning phase. In Figure 3, the base unit 34 is provided N with a fill inlet (in the form of fill pipe 34.2) and a drain outlet 34.4. However, in a some embodiments of a washing device according to the present disclosure, the fill © 30 inletand/or the drain outlet may be in the adapter unit, for example.

E o As discussed earlier, the washing device may comprise a heater unit for heating the N washing liguid, and an ultrasound unit that is configured to induce ultrasound N emission to the washing liguid. The heater unit may be in the form of an electric N 35 heater, such as a heater resistor. The heater unit heats the washing liquid that is inside the wash volume. Nominal power of the heater unit may be in the range of hundreds of watts to a few thousand watts, for example.

The heater may be positioned in the base unit, for example.

In Figure 3, the heater unit 36 is a heater resistor positioned inside the base unit 34. However, in some embodiments, the heater unit may be positioned outside the base portion to heat the washing liquid through the wall of the base portion, for example.

The heater unit may be provided with a thermostat that cuts the power to the heater unit when an upper temperature limit for the washing liquid is reached and turn the heater back on when the temperature of the washing liquid falls below a lower temperature limit.

In this manner, the heater is able to maintain the temperature of the washing liquid — within a desired range during the cleaning phase.

This range is preferably well above room temperature and less than boiling point of water.

For example, the temperature may be maintained in the range of 75 to 80 degrees Celsius.

The ultrasound unit comprises at least one ultrasound transducer.

Preferably, the ultrasound comprises a plurality of ultrasound transducers arranged to an array.

The array may be configured to generate ultrasound emission essentially in one direction (upwards) during use.

The ultrasound unit may be in the form of an ultrasonic plate, for example.

The ultrasound unit may be positioned inside the base unit such that the ultrasound emissions pass through the opening in the top — surface of the base unit and through the adapter unit.

The ultrasound unit can be removable or may be integrated to the base unit.

In Figure 3, for example, the ultrasound unit 38 is separate unit that is positioned directly below the opening in the top surface of the base unit 34, and an array of transducers 38.2 inside the ultrasound 38 are configured to emit ultrasound upwards.

Since the interior of the — base unit is filled with washing liquid during the cleaning phase, the ultrasound o unit may be in the form of a waterproof container containing the ultrasound S transducers.

As shown in Figure 3, waterproofbushing 34.6 may be used to provide N supply power for the transducers through the walls of the ultrasound unit 38 and a the base unit 34. © 30 E To ensure good results for the cleaning method in a reasonable time frame, high- o intensity ultrasound emissions are needed.

The transducer array may comprise ten N or more ultrasound transducers, for example.

Nominal power of the transducer N array may be in the range of hundreds of watts to a few thousand watts.

Asaresult, N 35 the size (i.e. effective surface area) of the transducer array may have to be larger than the size of the oil pan (and the opening in the top surface of the base unit).

Thus, some of the transducers may not have a direct path to the engine block.

However, if the ultrasound unit is positioned in base unit in the form of a large container filled with washing liquid during use (e.g. as shown in Figure 3), emissions from such transducers can be at least partially utilised.

Efficiency of the washing device may be improved by shaping and dimensioning the base unit and the adapter unit such that they guide ultrasound emissions to the engine block.

The time for ultrasound emissions in the cleaning method according to the present disclosure depends on the nominal power of the ultrasound unit.

The time may be in the range of tens of minutes to over an hour, for example.

As discussed earlier, the bearing surfaces of the engine block lack sufficient lubrication after the cleaning phase of the method according to the present disclosure.

The present disclosure describes an oil pump assembly for providing — said lubrication in the finalising phase of the method.

With the oil pump assembly, an external oil pump can be connected to oil circulation system (i.e. lubrication system) to cause circulation of oil when the engine is at standstill.

Figure 4 shows a simplified flow diagram of an oil circulation system 40 of an engine block of an internal combustion engine.

In Figure 4, an engine block 42 has an oil pan 42.1. An oil pump 44 of the engine is used to pump oil accumulating in the oil pan 42.1 to an oil filter housing 46 that is provided with an oil filter during normal use.

During normal use, oil filtered with the oil filter is recirculated back to the engine block 42. However, in the finalising phase of a method according to the present disclosure, after the oil pan has been attached back to its place, an external oil pump 48 may be attached to the oil filter housing and motor oil may be added to the engine block o (and penetrating oil may be sprayed to all cylinders, as mentioned earlier). The O external oil pump may be an electrical pump that has an oil pressure gauge, for eu example.

S 30 Inordertoattachthe external pump 48 to the oil filter housing, an oil pump adapter E 49 according to the present disclosure may be used.

Figure 5 shows a simplified o cross-sectional diagram of an exemplary embodiment of such adapter.

In Figure 5, N an oil filter adapter 49 comprises a first interface 49.1configured to be screwed to N the oil filter housing and a second interface 49.2 configured to be connected to an N 35 inletand an outlet of the external oil pump 48.

Since the engine block lack all lubrication, more than normal amount of motor oil may be needed. The engine block may be supplied with an amount of oil exceeding the recommended level by two litres, for example. Once the motor oil has been supplied, the external pump may be started, and the oil pressure may be checked. Ifa sufficient oil pressure is achieved (e.g. 2 bars = 30 Psi), the external pump may be kept running for a while (e.g. 5 to 10 minutes). As a result, an oil film is formed on the bearing surfaces. It is obvious to a person skilled in the art that the method and the tools for the — method can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims. o

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Claims

1. A washing device for cleaning an interior of an engine block of an internal combustion engine, wherein the washing device (30) comprises: - an engine interface (32.2) configured to be attached on an oil pan mounting surface of the engine block, wherein the engine interface (32.2) is configured to seal the interior of the engine block into an essentially closed volume, - aninlet(34.2) for supplying washing liquid to the closed volume, - a heater unit (36) for heating the washing liquid, - an ultrasound unit (38) comprising a plurality of ultrasound transducers (38.2), wherein the ultrasound unit (38) is configured to induce ultrasound emission to washing liquid in the closed volume.

2.A washing device according to claim 1, wherein the washing device comprises an adapter unit (32) that forms the engine interface (32.2).

3. A method for cleaning interior an engine block of an internal combustion engine, wherein the method comprises a preparation phase, cleaning phase and a finishing phase, wherein - the preparation phase comprises at least the steps of o draining motor oil from the engine block, o removing oil pan, and o aligning pistons, N - the cleaning phase comprises the steps of N o attaching a washing device (30) to claim 1 or 2 to the oil pan S mounting surface in place of the oil pan, 3 o filling the interior of the engine block with a washing liquid, z 30 o heatingthe washing liguid with the washing device (30), > o inducing ultrasound emission to the washing liquid with the N washing device (30), S o draining the washing liquid from the engine, o removing the washing device (30), and o letting any remaining washing liquid to evaporate,

- the finalising phase comprises at least the steps of o generating an oil film to bearing surfaces of the engine block without causing the engine parts to move, and o reassembling the engine.

4. A method according to claim 3, wherein the preparation phase comprises - mounting a piston position indicator (20) to a spark plug hole, wherein the piston position indicator (20) comprises o aproberod (22) configured to be inserted inside a cylinder, such that an end of the probe rod rests on a piston in the cylinder, o asleeve (24) around the rod (22), wherein the sleeve (24) has threads (24.1) for mounting the piston position indicator (20) to the spark plug hole and the probe rod (22) can slide freely inside the sleeve (24), and o markings indicating when the pistons are aligned, and - rotating a crankshaft of the engine block to align the pistons as indicated by the piston position indicator (20).

5. A method according to claim 3 or 4, wherein the finalising phase comprises - attaching the oil pan back, - attaching an external oil pump (48) to an oil filter housing of an oil circulation system of the engine block, - supplying the engine block with fresh motor oil, and O - using the external oil pump (48) for causing a circulation of oil in the oil circulation system in order to generate the oil film on the bearing surfaces.

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