CZ36603U1 - A device for supplying biofuel to an internal combustion engine and an assembly of an internal combustion engine with this device - Google Patents

Description

In the registration procedure, the Industrial Property Office does not determine whether the subject of the utility model meets the conditions of eligibility for protection according to § 1 of Act. No. 478/1992 Coll.

A device for supplying biofuel to an internal combustion engine and an assembly of an internal combustion engine with this device

Field of technology

The technical solution refers to equipment for the operation of an internal combustion engine on liquid biofuels, especially alcohols, for example methanol or ethanol, and is intended especially for small diesel internal combustion engines of generators with an output of up to 15 kW.

Current state of the art

Small internal combustion engines used in power plants up to 15 kW are usually powered by motor gasoline or diesel fuel. Operation on biofuels is not recommended, as materials are used that do not allow the use of these fuels.

In the case of gasoline engines, significant parts of the carburetor fuel system (CZ 291429, CZ 137634) are used, which are made of long-lasting materials that do not use biofuels, for example ethanol, butanol, methanol.

With diesel engines, the situation is similar, with the difference that engines with direct diesel injection into the cylinders are used, and when using biofuels, for example alcoholic fuels (EP 2940103, CZ 306084), vegetable oils, there is rapid damage to sealing elements and clogging of injectors ( PUV 2000-11207, CZ 279368, CZ 218279) by carbon deposits.

For large car or truck engines, sealing elements (EP 2661466) are used which are resistant to biofuels. The price of a regular sealing ring is around CZK 5 per ring, but in the case of biofuel-resistant sealing elements, it rises to the price of CZK 500 per ring.

The use of biofuels in gasoline engines is complemented by a system that adjusts the mixing ratio in order to achieve the optimal value of the excess air coefficient. This modification occurs directly in the engine control unit, to a limited extent, or on the basis of additional devices that are specially designed for this. At the same time, it is necessary to adjust the amount of fuel entering the internal combustion engine in order to achieve the same or similar values of performance parameters when operating on biofuels or mixed fuels of biofuels with gasoline, as when using motor gasoline according to the EN 228 standard.

In the case of diesel combustion engines of vehicles, fuel systems with direct fuel injection and Common Rail injection (EP 1651863, EP 1794432, EP 2628942) are used today, where injection pressures rise up to values of 250 MPa. This places increased demands on the purity of the fuel and leads to perfect tightness. The use of low-quality fuel causes damage to the fuel system and significant damage. In order to be able to use lower quality fuel, it is necessary to equip the engines with higher quality filter systems, preheating oil-based fuels, changing compression ratios when using alcohol-based fuels, rebuilding the diesel engine to use the principle of spark plugs, etc. The most modern vehicles then allow a complete rebuild, which equip the vehicle with a second fuel system that injects the second fuel into the combustion chamber directly via a special dual injector or a new injector placed instead of the glow plug, or into the intake (EP 2487353). It is then very challenging to coordinate the use of these two fuels through the control mechanisms so that the engine is operated in accordance with the regulations (EP 2634401, EP 2604842).

The use of these sophisticated systems would also be possible with small internal combustion engines, but it is not used for price reasons, where the production costs of such a device would make customers unwilling

- 1 CZ 36603 U1 accept. At the same time, in the case of small combustion engines, the regulations are not so strict and allow the use of even lower quality equipment.

The use of methanol directly as a fuel for diesel engines is not possible due to significantly different physical and chemical parameters. The use of methanol in a mixture (CZ 289953, EP 2982734, CZ 223981) with diesel is also not possible, stabilizers (dodecanol, isobutanol) (EP 2566830, EP 255007) must be added to the mixed fuel so that the mixture of diesel with methanol remains stable. The amount of methanol in diesel is still limited. During actual operation on a stable mixed fuel of diesel and methanol, the engine and its parts heat up at higher loads, which is also transferred to the fuel system and the methanol evaporates, which then causes the engine to run erratically.

The aim of the technical solution is to provide a device that will allow small diesel combustion engines to use methanol as fuel.

The essence of the technical solution

The presented technical solution relates to a device which, by placing it in the intake of a diesel combustion engine, makes it possible to burn liquid biofuel, especially methanol, as an additional fuel, without major technical modifications to the combustion engine. It can be used with advantage for small diesel combustion engines up to 15 kW, which are intended for driving electric generators or municipal equipment.

The subject of the presented technical solution is a device for the supply of liquid biofuel to an internal combustion engine, which contains a tank for liquid biofuel, connected by a pipe to a mixer of biofuel and air, to which is also connected an air supply through a suction pipe through a suction filter and a throttle valve for regulating the air supply to the mixer biofuel and air, wherein the biofuel and air mixer is adapted to be connected to the cylinder of the internal combustion engine, and wherein said device further comprises an intake filter of the internal combustion engine adapted to supply air through the intake pipe to the cylinder of the internal combustion engine. This part ensures the intake of air, which is necessary for the combustion of diesel fuel and thus ensures the standard operation of the combustion engine. The mentioned device, located on the intake of the diesel combustion engine, enables the intake to be divided into two parts and the diesel engine can thus suck from two different places.

The presented device ensures additional and regulated intake of air intended for the use of liquid biofuel (preferably methanol) and contains everything necessary for its preparation for combustion. When using a separate suction filter for the air supply to the biofuel-air mixer and a separate suction filter for the air supply to the combustion engine cylinder, the device settings must be checked regularly. The reason is that a constant suction ratio between the two suction branches is necessary for the correct operation of the device. Just as the intake filter becomes unevenly clogged due to the different amount of intake air, the proportion of the individual intake branches to the operation of the combustion engine changes and needs to be checked and adjusted regularly.

In an advantageous embodiment, the said device contains a common intake filter for both intake branches, i.e. connected in parallel via the intake pipe to the throttle valve for regulating the air supply to the biofuel and air mixer; and adapted to be connected to the intake manifold for supplying air to the cylinder of the internal combustion engine.

The common intake filter also gets clogged here, the amount of intake air is reduced and the resistance on the intake branch increases, but this is equally transferred to both intake branches (fossil fuel and biofuel, e.g. diesel and methanol) and there is no need for such frequent checks and adjustment of the intake ratio between air for fossil fuel and air with the addition of liquid biofuel.

- 2 CZ 36603 U1

For the controlled division of the intake air into two parts, the device must be equipped with at least one throttle valve, which determines this ratio and participates in the basic setting of the proportion of energy that is supplied to the diesel combustion engine via fossil fuel and which via liquid biofuel. The throttle valve is fitted to the part intended for air intake for use with liquid biofuel. Advantageously, it can also be used on both parts of the intake, for a more precise setting of the mixing ratio.

In this embodiment, the said device also includes a throttle valve for regulating the air supply from the intake filter of the combustion engine to the cylinder of the combustion engine. Advantageously, it includes a common intake filter, connected in parallel through the intake pipe to the throttle valve for regulating the air supply to the biofuel and air mixer; and to the indicated throttle valve for regulating the air supply to the combustion engine cylinder.

In one embodiment, the throttle valve is a three-way valve and a common intake filter is connected to said three-way valve, adapted to regulate the air supply through the intake manifold between the biofuel and air mixer and between the air supply to the combustion engine cylinder.

In an advantageous embodiment, the throttle valve and/or the three-way valve are adapted for thermal control, i.e. they are adapted to open the air supply only after the combustion engine has warmed up to a temperature of at least 30 °C.

In an advantageous embodiment, the mixer of liquid biofuel and air is a nozzle and a nozzle. More preferably, the nozzle is replaceable.

Further description of the design of the device is already limited to the part intended for sucking in liquid biofuel as fuel for a diesel combustion engine. This part contains a tank intended for the use of methanol or other liquid biofuel, preferably an alcoholic fuel with high volatility, a fuel line, a nozzle and a nozzle. When the air flows, a negative pressure is created in the nozzle and, due to this, the liquid biofuel is sucked in through the fuel nozzle. Its size determines the amount of methanol that is sucked into the intake air.

It could also be used on one intake line, which is intended for the intake of diesel, but the only way to adjust the ratio of the mixture of diesel and methanol is only on the nozzle used. The engine adjustment thus primarily represents a check of the condition of the nozzle without a possible change that can be caused by the use of a different alcoholic fuel. In such a case, changing the alcohol fuel would also require changing the nozzle. The proposed solution includes a throttle valve that will allow additional adjustment of the mixing ratio when using different types of alcoholic fuels or when the intake nozzle gradually wears out, which would otherwise require its immediate replacement.

Since the use is intended for small diesel combustion engines, there is no control unit included to adjust the amount of air intake or the amount of liquid biofuel intake. Ensuring the amount of fuel flowing into the engine continues to be ensured by the power regulator, which is a standard part of generator combustion engines and which adjusts the amount of injected base fuel, which is a fossil fuel such as diesel. Inside the internal combustion engine, a mixture of liquid biofuel (e.g. methanol) and intake air mixed with injected diesel fuel is simultaneously burned. The amount of energy to drive a small diesel engine is thus divided between fuel of petroleum origin (diesel) and alternative fuel produced on a biological basis (for example methanol and other alcoholic fuels).

The subject of the presented technical solution is also an assembly of a combustion engine for burning biofuel admixtures, which includes the above-described device and a combustion engine unit for fossil fuels, while the combustion engine unit contains a tank for fossil fuels, connected to an injection pump, which is connected to the cylinder through a fuel line an internal combustion engine connected to an electric power generator;

- 3 CZ 36603 U1 and whereas the said device according to the presented technical solution is connected to the combustion engine unit for fossil fuels through the biofuel and air mixer, which is connected to the cylinder of the combustion engine through the intake pipe for conducting the mixture of biofuel and air, and at the same time the intake filter is connected through the intake pipe, possibly through the throttle or three-way valve, to the cylinder of the combustion engine.

In one embodiment of the mentioned assembly, the internal combustion engine is a diesel internal combustion engine with an output of up to 15 kW.

In one embodiment of the mentioned assembly, the throttle valve is adapted to open the air supply for the mixture with biofuel only after heating the combustion engine to a temperature of at least 30 °C.

Clarification of drawings

Giant. 1: Combustion engine assembly and biofuel supply device with throttle valve and nozzle for simultaneous combustion of methanol and diesel fuel with a separate suction filter.

Giant. 2: Combustion engine assembly and biofuel feed device with throttle valve and nozzle for simultaneous methanol combustion and air control throttle valve for diesel combustion with a separate intake filter.

Giant. 3: Combustion engine assembly and biofuel supply device with throttle valve and nozzle for simultaneous combustion of methanol and air control throttle valve for diesel combustion with a common intake filter.

Giant. 4: Combustion engine assembly and biofuel supply device with throttle valve and nozzle for simultaneous combustion of methanol and diesel fuel with a common intake filter.

Giant. 5: Combustion engine assembly and biofuel supply device with a combined throttle valve for regulating the intake air for methanol and diesel fuel and a nozzle for the simultaneous combustion of methanol and diesel fuel with a common intake filter.

Examples of implementing a technical solution

Example 1

Equipment for supplying liquid biofuel to an internal combustion engine and its use

The basis of using a device for supplying liquid biofuel to an internal combustion engine is to allow internal combustion engines to burn two types of fuel simultaneously. The proposed solution is designed so that the energy for driving the combustion engine is divided between these two types of fuel in an adjustable ratio. The use of alcoholic fuels in diesel engines is not possible in principle, because alcoholic fuels differ significantly from the EN 590 standard or the EN 14214 standard, which regulate diesel and oil-based fuels. In particular, the cetane number differs considerably from the cetane number of diesel fuel (a cetane number of at least 51 is required by EN 590 and EN 14214). Methanol has a cetane number of around 3.

When using two energy sources, the calorific value of diesel is 42 MJ/kg and the calorific value of methanol is 20 MJ/kg. The stoichiometric ratio of diesel fuel is 14.5 : 1 and the stoichiometric ratio of methanol is 6.4 : 1. In order to maintain the performance parameters of the internal combustion engine when both fuels are used simultaneously, the amount of diesel fuel must be replaced by twice the amount of methanol. For the use of methanol, half the amount of clean air is needed, which does not entail any requirements for the intake design.

- 4 CZ 36603 U1

The device 120 can be used with advantage on an internal combustion engine 101 connected to an electric generator 102, into the combustion chamber of the cylinder 103 diesel fuel is injected as standard from the tank 105 via the injection pump 104 and the fuel line 111. Air to achieve the stoichiometric ratio is drawn in through the second intake pipe 114b and second air intake filter 106, see Fig. 1.

The device 120 can be used in five basic versions. The first embodiment of the device (Fig. 1) allows liquid biofuel - methanol - to be sucked from the tank 107 through the fuel line 112 into the engine intake through the vacuum created in the nozzle and sucks methanol from the nozzle, which together with the nozzle forms the biofuel and air mixer 109. In order it was possible to regulate the amount of intake air, a control first throttle valve 110 is placed in the first intake manifold 114a for air intake, which sets the basic mixing ratio for the use of diesel fuel and methanol in the internal combustion engine 101. After methanol is mixed with the intake air, this aerosol enters the of the combustion chamber of the engine cylinder 103 through the intake pipe 113. Air intake to maintain the stoichiometric ratio of methanol occurs through the first intake filter 108. As the second intake filter 106 and the first intake filter 108 are gradually clogged depending on the amount of passing air, the concept of the filters and settings of the control first throttle valve 110, do there is their clogging and a change in the basic ratio of diesel fuel and methanol in the cylinder 103 of the combustion engine 101, which requires regular inspection and adjustment.

The second embodiment of the device 120 (Fig. 2) allows the liquid biofuel - methanol to be sucked from the tank 107 through the fuel line 112 into the engine intake by means of the vacuum that is created in the nozzle and sucks methanol from the nozzle, which together with the nozzle forms the biofuel and air mixer 109. In order it was possible to regulate the amount of air taken in, a regulating first throttle valve 110 is placed in the first intake pipe 114a for air intake, which sets the basic mixing ratio for the use of diesel fuel and methanol in the combustion engine 101. For finer and more accurate regulation, the system is equipped with a second regulating throttle valve 119 for the amount of air intended for diesel fuel. After mixing the methanol with the intake air, this aerosol enters the combustion chamber of the cylinder 103 of the engine through the intake pipe 113. Air intake to maintain the stoichiometric ratio of methanol occurs through the first intake filter 108. As the second intake filter 106 and the first intake filter 108 are gradually clogged in depending on the amount of air passing through, the design of the filters and the setting of the regulating first throttle valve 110, they clog and change the basic ratio of diesel fuel and methanol in the cylinder 103 of the combustion engine 101, which requires regular inspection and adjustment. In order to be able to regulate more finely and accurately, not only the regulating first throttle valve 110 can be used to regulate the amount of intake air for methanol, but also the regulating second throttle valve 119 for regulating the intake air for diesel fuel.

The third embodiment of the device 120 (Fig. 3) is conceptually similar to the second embodiment except that separate first and second intake filters 106 and 108 are not used for air intake to diesel and methanol, but a common intake filter 118 is used. This eliminates requirement for frequent and regular adjustment of the ratio of diesel fuel and methanol in cylinder 103 of combustion engine 101.

The fourth embodiment of the device 120 (Fig. 4) is a combination of the first and third embodiments. The air is drawn in through a common intake filter 118 for both types of fuel, thereby reducing the need for regular and precise adjustment, and therefore the regulating second throttle valve 119 is no longer used to guide intake air for diesel fuel. This modification thus contains the smallest number of parts and is the easiest to maintain.

The fifth embodiment of the device 120 (Fig. 5) is based on the previous solutions, but in this case the air is sucked in through a common three-way throttle valve 117, which divides it in a set ratio between the air intended for diesel combustion and for methanol.

- 5 CZ 36603 U1

Industrial applicability

The presented assembly of the combustion engine and the device for supplying biofuel is intended for small diesel combustion engines up to 15 kW, which are intended to drive electric generators or municipal 5 technology. Its use makes it possible to burn methanol or other ethanol-based fuel in these engines as a propellant additive, which has a high volatility and a low cetane number.

Claims (9)

1. Device (120) for supplying liquid biofuel to an internal combustion engine, characterized in that it contains a tank (107) for liquid biofuel, connected by a pipe (112) to a mixer (109) of biofuel and air, to which the air supply of the first intake is also connected through a pipe (114a) through a first intake filter (108) and a first throttle valve (110) for regulating the air supply to the biofuel-air mixer (109), wherein the biofuel-air mixer (109) is adapted to be connected to the cylinder (103) of the internal combustion engine (101), while the device further comprises a second intake filter (106) of the combustion engine adapted to supply air through the second intake pipe (114b) to the cylinder (103) of the combustion engine (101). 2. The device according to claim 1, characterized in that it further comprises a throttle valve (119) for regulating the air supply from the second intake filter (106) of the internal combustion engine to the cylinder (103) of the internal combustion engine (101). 3. The device according to claim 2, characterized in that the first suction filter (108) and the second suction filter (106) are combined into a common suction filter (118), wherein the common suction filter (118) is connected by the first suction pipe (114a) to to the first throttle valve (110) for regulating the air supply to the biofuel and air mixer (109), and connected in parallel by the second intake pipe (114b) to the second throttle valve (119) for regulating the air supply to the cylinder (103) of the combustion engine (101). 4. The device according to claim 1, characterized in that the first intake filter (108) and the second intake filter (106) are combined into a common intake filter (118), adapted for supplying air through the second intake pipe (114b) to the combustion cylinder (103) of the engine (101), wherein said common intake filter (118) is connected in parallel through the first intake pipe (114a) to the throttle valve (110) for regulating the air supply to the biofuel/air mixer (109). 5. The device according to claim 4, characterized in that the first throttle valve (110) and the second throttle valve (119) are combined into a common three-way throttle valve (117), while the common intake filter (118) is connected to said common three-way valve ( 117), and wherein said common three-way valve (117) is adapted to switch the air supply through the first intake pipe (114a) to the biofuel and air mixer (109) and through the second intake pipe (114b) to the cylinder (103) of the combustion engine (101). 6. Device according to any one of the preceding claims 1 to 5, characterized in that the throttle valves (110, 117, 119) are adapted for thermal control. 7. Combustion engine assembly for burning biofuel admixtures, characterized in that it comprises a fossil fuel combustion engine unit comprising a fossil fuel tank (105) connected to an injection pump (104) which is connected to a cylinder through a fuel line (111) (103) of an internal combustion engine (101) connected to an electric power generator (102), wherein the device according to any one of the preceding claims 1 to 6 is connected to the cylinder (103) of the fossil fuel internal combustion engine unit. 8. Assembly according to claim 7, characterized in that the combustion engine (101) is a diesel combustion engine with an output of up to 15 kW. 9. Assembly according to claim 7 or 8, characterized in that the throttle valves (110, 117, 119) are adapted to open the air supply for the mixture with biofuel only after the combustion engine (101) has been heated to a temperature of at least 30 °C.