SE1351024A1 - Combustion engine fuel system, internal combustion engine with such a fuel system, vehicles with such a fuel system and a method of dampening pressure fluctuations in a fuel system - Google Patents

Abstract

Summary The invention relates to a fuel system (4) for an internal combustion engine (2), which fuel system (4) comprises a fuel filter device (24) arranged between an electric motor-controlled low-pressure pump (22) and a high-pressure pump (26), the fuel filter device (24) comprising a filter housing (24). 40), in which a filter element (32) and an accumulator (34) are arranged to vapor pressure fluctuations in the fuel system (4). An electrically controllable valve (36) is further provided with the fuel filter device (24) for controlling the accumulator (34). The invention also relates to an internal combustion engine (2) with such a fuel system (4), vehicle (1) with such a fuel system (4) and a process for vaporizing pressure fluctuations in a fuel system (4).

Description

FIELD OF ART The present invention relates to a fuel system for an internal combustion engine, an internal combustion engine with such a fuel system, vehicles with such a fuel system industry systems and a process for vaporizing pressure fluctuations in one industry system.

BACKGROUND OF THE INVENTION AND KNOWLEDGE TECHNOLOGY Internal combustion engines, such as diesel or otto engines, are used in several types of applications and vehicles today, for example in heavy vehicles, such as trucks or buses, cars, motor boats, ships, ferries or ships. Internal combustion engines are also used in industrial engines and / or motor-driven industrial robots, power plants, such as e.g. electric power plant that includes a diesel generator, and in locomotives.

Internal combustion engines can be powered by diesel or petrol. These engines are equipped with a fuel system to transport the fuel from one or more fuel tanks to the internal combustion engine injection system. The fuel system includes one or more fuel-driven fuel pumps the internal combustion engine or driven by an electric motor. The fuel pumps create an industry flow and pressure to transport the industry to the internal combustion engine's injection system, which Ulf & the industry to the internal combustion engine's combustion chamber.

Fuel pumps powered by an electric motor due to the possibility of operating the fuel pump independently of the internal combustion engine speed and allow 2 then set a wider control range than a mechanically driven pump, which is controlled by the speed. The fuel volume supplied via the electric fuel pump can thus be better adapted to the combustion engine's fuel inlet at the same time as the fuel pump's energy inlet and overcapacity can be minimized. To minimize energy consumption and thus fuel consumption, it is necessary to let the fuel pump operate at as high a speed as possible and to pump the smallest possible volume of fuel into the fuel system. However, this means that the fuel system becomes susceptible to rapid fluctuations in the combustion engine's fuel needs. In the event of an operation, the needs of the internal combustion engine are, for example, rapidly reduced fluctuates from a small industry volume to a large industry volume, demands that the fuel pump just as quickly changes the fuel volume it pumps to the combustion notch. If this does not happen, the consequence will be a temporary pressure drop in the fuel system, which risks affecting the combustion engine's emissions and operation. Correspondingly, there can be a delay in the fuel pump's regulation cause occasional pressure spikes then the combustion engine's fuel needs quickly others' Iran a large industry volume to a small industry volume. These pressure fluctuations can also reduce responsibilities to control the fuel pump, which affects fuel consumption. This is a problem that can arise when, for example, driving in hilly environments.

Various methods and systems have been proposed in the prior art for vaporizing pressure fluctuations in industrial systems. For example, document JP10227269 A discloses a fuel system for an internal combustion engine, which comprises a fuel filter with an accumulator, arranged between a low pressure pump and a high pressure pump. The accumulator includes a gas-filled one spring and aims to vapor pressure fluctuations in the industry which is returned Than high pressure pump to the industry filter.

Furthermore, in document DE2725787 C3 a branch system comprising one is described device for vaporizing pressure fluctuations in the fuel supplied to one dirty filter of industry filters. The device comprises an accumulator below a spring-supported diaphragm which is affected by the incoming fuel and forms pairs. 3 any fluctuations. The fuel is then passed on to a filter element and then further out into the fuel system.

Despite known solutions in the field, there is still a need to further develop an industry system that helps to dampen pressure fluctuations thereby reducing industry consumption and minimizing the risk of damage to the industry system. SUMMARY OF THE INVENTION The object of the present invention is to provide a fuel system for an internal combustion engine, which allows a flexible control of the fuel supply and which reduces the parasite losses.

The object of the invention is also to provide a fuel system for an internal combustion engine which vaporizes pressure fluctuations in the fuel system.

Furthermore, it is an object of the invention to provide an industry system for an internal combustion engine, which is compact and space-efficient.

A further object of the present invention is to provide a fuel system for an internal combustion engine which minimizes fuel consumption.

Furthermore, it is an object of the present invention to provide one fuel system for an internal combustion engine, which minimizes the risk of damage during the occurrence of fuel leakage.

A further object of the present invention is to provide one industry systems where downtime can be detected before the industry pressure has reached others essentially. 4 These objects are achieved with an industry system as defined in claim 1 and a method for regulating an industry system as defined in claim 10.

According to the invention, the above objects are achieved with an industry system for one internal combustion engine comprising an fuel filter device disposed between single motor controlled low pressure pump and high pressure pump.

The fuel filter device comprises a filter housing, in which a filter element and an accumulator are arranged to vapor pressure fluctuations in the fuel system. Furthermore, an electrically controllable valve is provided at the fuel filter device to control the accumulator.

The invention also relates to a combustion engine and a vehicle comprising the system described above.

In another aspect, the invention relates to a process for steaming pressure fluctuations in an industry system, which industry system comprises an industry filter device arranged between an electric motor-controlled low-pressure pump and a high-pressure pump, used in the industry filter device comprising a filter housing, in which a filter element and an accumulator are arranged to vapor pressure fluctuations in the industry system and accustomed to the procedure include the steps of: (a) identify the occurrence of operational cases with rapidly changing industry access when there is a risk of pressure fluctuations in the industry system; (b) control an electrically controllable valve so that the accumulator is activated and the pressure fluctuation is steamed.

DETAILED DESCRIPTION OF THE INVENTION The invention is described below with reference to the industry system and method generally described above.

By arranging an electric motor-controlled low-pressure pump in a fuel system, a wider control range is allowed with a mechanical pump, which is usually driven and controlled by an internal combustion engine and above all by the speed of the internal combustion engine.

The electric motor-controlled low-pressure pump can be controlled against other parameters engine speed, such as industry filter efficiency and pressure in industry lines. In order to optimize fuel consumption, the electric motor-controlled low-pressure pump should be operated at as low a speed as possible and deliver as small a fuel volume as possible in the fuel system. This medic & However, the fuel system becomes susceptible to rapid fluctuations in the fuel demand of the internal combustion engine as the negative pressure pump must be quickly regulated to be adapted to the actual fuel demand. There is some delay between the internal combustion engine's change in fuel demand and the legal pressure pump's speed control, which results in temporary pressure fluctuations in 15 industry system. By arranging an accumulator in the fuel filter device, a fuel system is provided, which generates pressure fluctuations in the fuel system and which in this way can minimize the fuel consumption without being affected by the varying fuel needs of the internal combustion engine. Furthermore, the evaporation of pressure fluctuations results in a more stable control of the low-pressure pump, which in turn leads to lower industry consumption.

By arranging an electrically controllable valve of the fuel filter device, all passages to and from the accumulator can be closed and opened so that the function of the accumulator can be controlled between inactive and active in a flexible manner. By controlling the valve based on predetermined parameters, a fuel system is achieved where the accumulator is only active in certain specific operating cases when it is really needed, which minimizes the fuel system's energy access and thus minimizes fuel consumption. In the event of an operation, the internal combustion engine's fuel needs quickly change from a smaller one industry volume to a large industry volume presents a delay at the regulation of the legal pressure punch and pressure drop occurs in the industry system. The electrically controllable valve is then controlled so that the passages to and from 6 the accumulator is opened and pressurized fuel at the accumulator can be supplied to the fuel system and thereby generate the pressure drop until the speed of the low-pressure pump has been adapted to the combustion engine's fuel needs. In the event of a breakdown, the combustion engine's industry needs quickly change from a larger industry to a smaller amount of industry entails the delay in the regulation of the negative pressure pump a temporary pressure nail or an excess pressure. The electrically controllable valve is then controlled so that the passages to and from the accumulator are opened and excess fuel is supplied to the accumulator instead of the other fuel system and thus the pressure spike is steamed. In the event of an operation, the fuel pressure reaches the internal combustion engine if requested, the valve is controlled suitably so that the accumulator is filled with one pressurized industry volume corresponding to the delay between the regulation of the legal pressure pump and the combustion notor's change in industry needs. In this way, the accumulator is ready to supply pressurized fuel to the industry system in the event of a possible pressure drop. The accumulator can be suitably designed said that there is room left for receiving excess industry volume at the appearance of a possible pressure nail. The volume of the accumulator can be, for example, between 0.5-10 liters, preferably between 0.5-1.5 liters, but even larger volumes are possible if space is available.

The electrically controllable valve also carries a safety aspect by the accumulator can be deactivated, for example, in the event of industry leakage in the accumulator or in the industry system. In this way, the industry from the accumulator is prevented from leaching to the environment and thus an industry system is created, which minimizes the risk of damage during the occurrence of 25 industry paint.

The electrically controllable valve is preferably a solenoid valve but may be any electric valve.

The accumulator is preferably arranged in the clean of the fuel filter device side, that is to say at the outlet of the fuel filter device. Furthermore, the accumulator is preferably arranged integrated with the filter element for this purpose 7 achieve a compact and space-efficient industry filter device and thus a compact and space-essential industry system.

Furthermore, the accumulator suitably comprises a cylinder, which is divided into two chamber through a piston. The piston preferably has a spring arranged on it side that is not in contact with the fuel, which spring determines the fuel pressure that the accumulator creates. The spring can be, for example, mechanical or a gas pressure spring. A lamp, for example an o-ring, is arranged around the periphery of the piston to seal the chamber comprising the spring against industry.

By arranging a non-return valve, for example a non-combustion valve, at the inlet to the accumulator a flow control is provided where fuel is supplied to the accumulator through a larger opening than through which fuel flows out of the accumulator. The restriction of the fuel flow out of the accumulator means that the pressure of the industry supplied to the industry system is constant. Lamply, non-return valves in the form of, for example, diaphragm valves are also arranged at the outlet of the filter element, in order to prevent the pressurized fuel Iran accumulator from being led back to the filter element and the low-pressure pump.

The electrically controllable valve is arranged in connection with a control unit which is suitably connected to a CAN bus. The other control units of the vehicle can in turn also be connected to the CAN bus and thereby the control unit of the valve can receive information from the other control units. This information can aptly used as control parameters when controlling the valve. Valves control unit can be either a separate unit only for controlling the valve and thus the accumulator or it can be connected to the control unit of the low pressure pump. The control unit of the low pressure pump is suitably constituted by the control unit of the electric pressure pump controlling the electric motor.

Preferably, a pressure sensor is arranged downstream of the industry filter device. The pressure sensor measures the industry pressure according to the industry filter device and is via 8 The CAN bus is arranged in connection with the valve control unit so that the control unit can decide whether activation of the accumulator is necessary. Alternatively, a pressure sensor is arranged downstream of the low pressure pump and upstream of the industry filter device or both upstream and downstream. the industry filter device. The pressure sensor preferably comprises control logic and star in direct connection with the CAN bus. Alternatively, the pressure sensors are arranged in connection with the control unit of the low-pressure pump, which in turn is connected to the CAN bus and thereby to the control unit of the valve.

The electrically controllable valve of the fuel filter device is suitably controlled through the control unit based on parameters such as GPS for vehicle position, topographic data, n notor speed, vehicle load, nnotor load, vehicle speed, accelerator pedal, industry pressure before and after the industry filter device, industry temperature, pump speed or similar parameters that identify operating cases when the combustion engine's fuel requirements vary rapidly and then the risk of pressure fluctuations in the industry system are present. These parameters can be obtained via the CAN bus Than other control units of the vehicle. By detecting these operating cases before the industry pressure has reached another level, the accumulator can be activated at an early stage and the pressure fluctuations can be evaporated. To for example, the valve control unit can identify an upcoming downhill slope, which means that the internal combustion engine's fuel demand during engine braking decreases rapidly. The valve is then controlled so that the passages to and from the accumulator are opened (the accumulator is activated) and the accumulator is filled / charged with excess fuel. In the same way, the valve control unit can identify an upcoming one upporsbacke, which means that the combustion engine's fuel needs increase, and the valve is controlled so that the accumulator is activated and pressurized fuel from the accumulator is added to the fuel system at the uphill! Dolan.

Further advantages of the invention will become apparent from the following details description of the exemplary embodiments of the invention. 9 BRIEF DESCRIPTION OF THE DRAWINGS In the following, by way of example, preferred embodiments of the invention are described with reference to the accompanying drawings, in which: Fig. 1 shows a schematic side view of a vehicle, which comprises a fuel system for an internal combustion engine according to the present invention, Fig. 2 shows a wiring diagram for a branch system according to the present invention, Fig. 3 shows a cross-sectional view of an industry filter device according to present invention, Fig. 4 shows a flow chart of a process for steaming pressure fluctuations in an industry system according to the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION Fig. 1 shows a schematic side view of a vehicle 1, which vehicle comprises one fuel system 4 for an internal combustion engine 2 according to the present invention.

The internal combustion engine 2 is connected to a gearbox 6, which is connected to the drive wheel 8 of the vehicle 1 via a transmission. The vehicle also includes a chassis 10. Fig. 2 shows a circuit diagram of a fuel system 4 for an internal combustion engine 2 according to the present invention. The fuel system 4 comprises a fuel tank 20, a low pressure pump 22, a fuel filter device 24, a high-pressure pump 26 and an internal combustion engine 2. The low-pressure pump 22 pumps fuel Than the fuel tank 20 through the downstream fuel filter device 24 and on to the high-pressure pump 26 which then pumps the fuel on to the internal combustion engine 2. The low-pressure pump 22 is driven by an electric motor M1, which comprises a control unit (not shown), which is arranged in connection to a CAN bus 30. The fuel filter device 24 comprises a filter element 32 through which fuel Than fuel tank 20 is filtered. Downstream of the filter element 32 is an accumulator 34 arranged to vaporize pressure fluctuations of the fuel from the low pressure pump 22. An electrically controllable valve 36 is arranged downstream of the filter element 32 to control the accumulator 34. The electrically controllable valve 36 is preferably a solenoid valve and is arranged in connection with a control unit 28, which via connection to the CAN bus 30 communicates with other control units of the vehicle 1. Thus, the control unit 28 of the valve 36 can obtain control parameters. vehicle 1, said as topographic data, engine speed, vehicle load, engine load, vehicle speed, accelerator pedal, fuel pressure before and after the fuel filter device, fuel temperature, pump speed or similar parameters. The valve 36 can be controlled so that the passages to and from the accumulator 34 are opened or closed, which in this way activates or deactivates the accumulator 34. At the inlet / outlet of the accumulator 34 is a non-return valve 38 and a throttle valve arranged. More details about the valves of the fuel filter device 24 are described in Figure 3. On the rear sides of the fuel filter device 24, pressure sensors 42, 44 are arranged to detect the fuel pressure before and after the fuel filter device 24. The pressure sensors 42, 44 comprise control logic and connection with the CAN bus 30. Instead of its own control logic at the pressure sensors they could be connected to the control logic of the legal pressure pump's electric motor (M1) (not shown).

Fig. 3 shows a cross-sectional view of the fuel filter device 24 according to the present invention invention. The fuel filter device 24 comprises a filter housing 46 in which the filter element 32 and the accumulator 34 are arranged. The accumulator 34 is arranged on the clean side of the fuel filter device 24, which meant that the fuel 11 Than the fuel tank 20 is first filtered through the filter element 32 and then can flow into the accumulator 34 or further out into the fuel system 4. How the fuel flows through the fuel filter device 24 is illustrated by the arrows with male reference F. At the filter element 32 outlet, check valves 48, e.g. in the form of diaphragm valves, arranged. In this way, pressurized fuel is prevented from the accumulator 34 to flow back into the filter element 32 and towards the negative pressure pump 22. The accumulator 34 comprises a cylinder 50 which is divided into two chambers by a piston 52. The piston 52 receives inflowing fuel on its one side and has on the opposite side a spring 54 arranged. The spring 54 may be a mechanical spring or a gas pressure spring, which is compressed when the accumulator 34 is filled with fuel which presses against the piston 52. The piston 52 moves downwards along a direction A under the influence of the fuel and the spring 54. The spring 54 thus determines the industry pressure which the accumulator 34 produces. Around the periphery of the piston 52 is a ridge 56 arranged, for example, an o-ring, so that the branch does not reach the chamber in which the spring 54 is provided. At the inlet to the accumulator 34 there are non-return valves 38, for example in the form of diaphragm valves, arranged and a throttle valve 40. Fuel can flow into the accumulator 34 through the diaphragm valves 38 and the throttle valve 40 but can only flow out of the accumulator 34 through throttle valve 40. In this way a constant pressure is achieved in the industry in the accumulator 34. The electrically controllable valve 36 is arranged substantially coaxially with the accumulator 34 and comprises a movable member 58 which can frame along the direction A. The valve 36 can be controlled so that the movable member 58 moves towards or away from the accumulator 34 and rods / disables respectively activates the armed accumulator 34. In the accumulator 34 activated condition, the valve 36 is so controlled that a passage is provided between the movable member 58 and the inlet of the accumulator 34. Filtered fuel can then flow into the passage, through the diaphragm valve 38 and the throttle valve 40 further into the accumulator 34 or out through the throttle valve 40 and the passage and further out in the fuel system 4. In the inactivated state of the accumulator 34 is the valve 36 is so controlled that the movable member 58 abuts the accumulator 34 12 inlet and no fuel is allowed to pass between the movable member 58 and the inlet of the accumulator 34.

Fig. 4 shows a flow chart of a process for steaming Pressure fluctuations in the fuel system 4 according to the present invention. The method according to the invention comprises the step (a) of identifying the occurrence of operating cases with rapidly changing industry access when there is a risk of pressure fluctuations in the industry system 4. Further, the method comprises the step (b) of controlling the electrically controllable valve 36 so that the accumulator 34 is activated and the pressure fluctuation is steamed.

Step (a) may further comprise including a pressure sensor 44 identifying the fuel pressure after the fuel filter device 24 and thereby determining if pressure fluctuations occur.

The step (a) may also comprise that based on parameters such as GPS for vehicle position, topographic data, engine speed, vehicle load, engine load, vehicle speed, accelerator pedal, fuel pressure, industry temperature or pump speed identify operating drops as the internal combustion engine's 2 fuel requirements vary. rapid and risk kir pressure fluctuations in the industry system 4There are.

Step (b) may further comprise, at the identified risk of pressure drop, controlling the valve 36, so that the accumulator 34 is activated and pressurized fuel at the accumulator 34 can be supplied to the fuel system 4 and thus evaporate the pressure drop.

Step (b) may also comprise, at the identified risk of pressure spikes, controlling the valve 36, so that the accumulator 34 is activated and excess fuel can accumulate at the accumulator 34 and thus evaporate the pressure spike. The stated components and features listed above may be within the scope of the invention can be combined with the same embodiments. 13

Claims (14)

Patent claims A combustion engine (4) for an internal combustion engine (2), the fuel system (4) comprising a fuel filter device (24) arranged between an electric motor controlled low pressure pump (22) and a high pressure pump (26), used in the fuel filter device (24) comprising a filter housing (46). ), in which a filter element (32) and an accumulator (34) for steam pressure fluctuations in the fuel system (4) are arranged, characterized in that an electrically controllable valve (36) is arranged in the fuel filter device (24) for controlling the accumulator (34 ). Fuel system according to claim 1, characterized in that the accumulator (34) is arranged on the clean side of the fuel filter device (24) and uses down filtered fuel. Fuel system according to claim 1 or 2, characterized in that the accumulator (34) comprises a cylinder (50), which is divided into two chambers by a piston (52). Fuel system according to one of the preceding claims, characterized in that the electrically controllable valve (36) is arranged in connection with a control unit (28) and a CAN bus (30). Fuel system according to one of the preceding claims, characterized in that a non-return valve (38) is arranged for supplying fuel into the accumulator (34). Fuel system according to one of the preceding claims, characterized in that the electrically controllable valve (36) is controlled on the basis of parameters that can identify operating conditions when the combustion engine's (2) fuel requirements vary rapidly and when there is a risk of pressure fluctuations in the fuel system (4). , topographic data, engine speed, vehicle load, engine load, vehicle speed, accelerator pedal, fuel pressure, fuel ignition temperature or pump speed. 14 Fuel system according to any one of the preceding claims, characterized in that it comprises a pressure sensor (44) for identifying the fuel pressure after the fuel filter device (24). Internal combustion engine (2) characterized in that it comprises a fuel system (4) according to any one of claims 1-7. Vehicle (1) characterized in that it comprises a fuel system (4) according to any one of claims 1-7. A method of vaporizing pressure fluctuations in a fuel system (4), the fuel system (4) comprising a fuel filter device (24) disposed between an electric motor controlled low pressure pump (22) and a high pressure pump (26), the fuel filter device (24) comprising a filter housing (46). ), in which a filter element (32) and an accumulator (34) are arranged to vapor pressure fluctuations in the fuel system (4), used in the method comprising the steps of: 1. identifying the occurrence of operating cases with rapidly changing fuel flow and the risk of pressure fluctuations in the fuel system (4) is present, 2. controls an electrically controllable valve (36) so that the accumulator (34) is activated and the pressure fluctuation is evaporated. A method according to claim 10, used in step (a) comprising identifying the fuel pressure after the fuel filter device (24) by means of a pressure sensor (44) and thereby determining whether pressure fluctuations occur. A method according to claim 10, used in step (a) comprising, based on parameters such as GPS for vehicle position, topographic data, engine speed, vehicle load, engine load, vehicle speed, accelerator pedal, fuel pressure, fuel temperature or barrel speed, identify operating cases as the combustion engine (2) fuel requirements vary rapidly and there is a risk of pressure fluctuations in the industry system (4). A method according to any one of claims 10-12, used in step (b) comprising, at the identified risk of pressure drop, controlling the valve (36) so that pressurized fuel at the accumulator (34) can be supplied to the fuel system (4) and then evaporating. the pressure drop. A method according to any one of claims 10-12, used in step (b) comprising, at the identified risk of pressure spikes, controlling the valve (36) so that excess fuel can accumulate in the accumulator (34) and thereby steam the pressure spike. 1/4 Z .6! D 3/4