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Patent Searching and Data


Title:
A METHOD AND MEANS FOR DRIVING AN INTERNAL COMBUSTION ENGINE AND A COMPRESSOR
Document Type and Number:
WIPO Patent Application WO/2006/005341
Kind Code:
A1
Abstract:
When, according to the invention, a compressor is driven via a variable drive system for an internal combustion engine, an unprecedented possibility of improving and regulating the output power of the engine is achieved, more or less independently of the number of revolutions. This allows the use of smaller four-stroke engines, which may achieve a characteristic which essentially corresponds to what applies to a two-stroke engine. Finally, it provides the possibility of adapting the air supply of the compressor to the requirements of the engine under the given operating conditions, thereby achieving considerable operating savings.

Inventors:
KOLSTRUP ANDERS PETER (DK)
Application Number:
PCT/DK2005/000479
Publication Date:
January 19, 2006
Filing Date:
July 07, 2005
Export Citation:
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Assignee:
ROTREX AS (DK)
KOLSTRUP ANDERS PETER (DK)
International Classes:
F02B33/00; F02B67/10; B60K25/02; (IPC1-7): F02B33/00; B60K25/02; F02B67/10
Foreign References:
US6609505B22003-08-26
EP1416134A12004-05-06
FR2689568A11993-10-08
US5462035A1995-10-31
US5256109A1993-10-26
US6408832B12002-06-25
Attorney, Agent or Firm:
LARSEN & BIRKEHOLM A/S SKANDINAVISK PATENTBUREAU (P.O. Box 362, Copenhagen V, DK)
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Claims:
PATENT CLAIMS
1. A method of driving an internal combustion engine and a compressor, cha ra cte rized in that the connection between the engine and the compressor comprises a variable drive.
2. A method according to claim 1, characterized in that the drive is independently adjustable.
3. A drive for use in the method of claims 1 and 2, characterized in that the variable drive consists of two or more fixed gear ratios.
4. A drive according to claim 3, c h a ra cte ri ze d in that it may be connected via a clutch.
5. A drive for use in the method of claims 1 and 2, characterized in that the variable drive is continuously variable.
6. A drive according to claim 5, characterized in that the drive may be locked in predetermined gear ratios.
7. A compressor for use in the performance of the method of claims 1 and 2, characterized in that it is a centrifugal charger.
8. A compressor for use in the method of claims 1 and 2, character¬ ize d in that it is a displacement charger.
Description:
A METHOD AND MEANS FOR DRIVING AN INTERNAL COMBUSTION ENGINE AND A COMPRESSOR

The prior art The invention relates to a method of driving an internal combustion engine and a compressor as well as means for performing the method.

US 6 609 505 B2 discloses a two speed gear which is used for driving a centrifugal charger for an internal combustion engine. A two speed gear according to this patent is composed of two complete planetary gears which are coupled together in some of the various ways proposed in the patent. The two speed effect is then achieved by keeping selected parts of the gear stationary in relation to the engine. As the prior art results in a solution with two separate planetary gears, it becomes larger, more expensive to manu- facture and less reliable in operation.

US 6 055 967 discloses a compressor, more particularly a screw compres¬ sor equipped with various recycling devices which serve the purpose of adjusting the flow of air to an engine. Irrespective of the configuration of these recycling systems, the air is heated unduly with respect to a situation where the compressor operates with a controlled optimum number of revo¬ lutions.

US 6 408 832 discloses a screw compressor mounted on an outboard mo- tor, where it is necessary to recirculate air in response to the load and the revolutions of the motor. It is attempted to reduce the resulting increased air temperature by an effective and expensive charging cooler.

Finally, WO 02/064997 discloses a gear for high speeds and a great gear ratio. In this gear, however, the gear ratio cannot exceed 13.6:1 because of the geometry, as, in this situation, the planets are in physical contact with each other, and even though this gear ratio is great, there are situations where a greater gear ratio is desirable.

The object of the invention

The object of the invention is to remedy these defects and drawbacks, while improving the operating conditions for engines, and this is achieved ac¬ cording to the invention by a method, wherein the connection between the engine and the compressor comprises a variable drive.

In this effective manner, it is possible to improve the operating conditions, particularly by ensuring an optimum output torque extending continuously from the lowest to the highest number of revolutions, at the same time as the costs of manufacturing the variable drive, its dimensions and the oper- ating reliability meet the strictest requirements in these respects.

When, as stated in claim 2, the drive is made independently variable, the charging pressure may constantly be regulated by means of the variable drive system to the most effective one in the situation of operation.

When, as stated in claim 3, the drive is constructed such that it consists of two or more gear ratios, the drive may be composed to achieve a compact and very reliable gear.

When, as stated in claim 4, a clutch, such as a one-way clutch, is incorpo¬ rated between the gear and the charger, it may be ensured that the charger may work unobstructedly when the gear stands still or rotates slowly.

When, as stated in claim 5, the drive is constructed to be continuously vari- able, the output torque may always ensured independently of the number of revolutions. When, as stated in claim 6, the gear may be locked in fixed gear ratios, a control possibility for the operation is achieved, which may hereby be preset to achieve the best operating conditions.

When, as stated in claim 7, a centrifugal charger is used, one- and two-cyl¬ inder engines may have a performance at the level of e.g. four-cylinder en¬ gines.

Finally, it is expedient, as stated in claim 8, to use a displacement charger, whereby this, in connection with the variable drive, may provide the opti¬ mum engine characteristic.

Description of exemplary embodiments Examples of embodiments of the method and the means therefor will be described more fully below.

The starting point of the invention is a wish for improving the operating con¬ ditions by "evading" the common limitations which exist with respect to the engine type and kind, two-stroke and four-stroke engines, the number of cylinders and the differences of the output torque in dependence on the number of revolutions, etc.

To this should be added the "evasion" of conditions such as the air tem¬ perature which causes knocking to occur in engines if the inlet air is too hot.

Therefore, the air supply with pressure charging must be adapted carefully to the current operating state of the engine. This ensures the possibility of a higher compression ratio and earlier ignition and thereby a greater engine performance and a lower fuel consumption.

This provides the possibility of reducing the dimensions of the pressure charged engines and also the possibility of operation with a higher charging pressure.

This applies no matter whether a displacement charger or a centrifugal charger is used, since the number of revolutions of the engine and of the charger will be independent, thus allowing an optimum operating charac¬ teristic.

Moreover, the variable operating system allows regulation of the charging pressure in operation and thereby a limitation of the energy consumption of the compressor.

With respect to the engine type, a four-stroke engine may be caused to have a performance which essentially corresponds to the performance of a corresponding two-stroke engine by the method of the invention, and the pressure charging of a four-stroke engine will allow a reduction of the en¬ gine dimensions to a much greater degree because of the higher perform¬ ance of the engine.

As mentioned, the variable drive allows the number of revolutions of the compressor to be regulated in relation to that of the engine. If the engine is made smaller, it is possible to compensate with a higher charging pressure to achieve the desired output power.

Finally, a separate compressor may advantageously be mounted, and the variably driven compressor means from a centrifugal charger may be al¬ lowed to drive the compressor means, the impeller, of the turbo-charger by means of a one-way clutch.

In such a structure, the variable gear may rotate the compressor wheel of the turbo-charger with the desired number of revolutions, following which the turbine in the turbo-charger may take over.

The one-way clutch between the gear and the turbo-charger ensures that the turbo-charger can operate unobstructedly when the gear stands still or rotates slowly.

The variable gear may optionally be disconnected.

Five examples of the use of the method and means will now be described.

Example 1 An outboard motor must be capable of lifting the boat out of the water for planing, while the motor continues to operate with a low number of revolu¬ tions, since, usually, there is neither a clutch nor a gearbox like in a car. Transition from two- to four-stroke engines causes problems of lifting the boat out of the water at low revolutions. Owing to the high volumetric effi¬ ciency of the two-stroke engine it has a high torque at the current low num¬ ber of revolutions, which makes it extremely suitable.

A centrifugal charger or a screw compressor combined with a CVT (Con¬ tinuously Variable Transmission) drive will give the constructer of four- stroke engines the absolutely best option, even better than the corre¬ sponding two-stroke performance.

Example 2 A particular performance characteristic is desired in certain vehicles. In powerful motorcycles, a constant torque course up through the revolutions is very important. Serious accidents with turbo-charged motorcycles show clearly that a too strong change in the torque makes a motorcycle very dangerous to drive. A directly driven compressor whose number of revolu¬ tions is adapted to the situation, allows the performance to be enhanced, without this being at the expense of the safety. Certain countries have im¬ posed limitations on the maximum performance for reasons of safety. The variable drive is suitable here, since the engine may then be constructed more optimally.

Example 3 Owing to its size and high efficiency, the variably driven centrifugal charger is very suitable for bringing the level of performance of one- or two-cylinder engines to that of the otherwise more powerful four-cylinder engines. This has evident advantages in compact applications.

Example 4 The so-called water vehicles (water scooters) is another field in which a variable drive significantly improves the characteristic of the engine and thereby the behaviour of the boat.

Example 5 Turbo-charged downsize engines with a large turbo-charger. A variable gear driving the compressor wheel in the turbo-charger in common with the turbine of the turbo-charger, will provide the optimum charging pressure under all conditions.

For the exemplary embodiments 1 , 4, and 5, both a centrifugal charger and a displacement charger are suitable, in combination with a variable drive.

For the exemplary embodiments 2 and 3, a centrifugal charger is the most effective solution.