Internal combustion engine fuel supply system

Abstract

 Internal combustion engine supply system whereby petrol is supplied from a main tank and, under special running conditions, provision is made for an additional supply of alcohol and for conveying the oil vapour and gas from the engine block into the engine itself.

Description

[0001] The present invention relates to an internal combustion engine supply system comprising a main fuel tank, a carburetor upstream from the engine intake header and complete with a throttle valve, and means for supplying fuel from the main tank to the carburetor.

[0002] The aim of the present invention is to provide a supply system of the aforementioned type designed to enable a high degree of engine efficiency. The main characteristic of the present invention is that the said supply system also comprises :

. an auxiliary alcohol tank;

. means for conveying a mixture of air and alcohol from the auxiliary tank into an outlet pipe on the tank itself;

. a control electrovalve having :

. a first inlet communicating with the inner cavity on the engine block, for receiving the oil vapour and gas coming from the block;

. a second inlet communicating with the said outlet pipe on the auxiliary tank;

. a first and second outlet communicating respectively with the intake pipe on the engine up- and downstream from the throttle; and

. a moving member recalled elastically into a first operating position in which the said second inlet and the said second outlet are isolated and the said first inlet communicates with the said first outlet, provision being made for moving the said moving member, by energizing the solenoid on the electrovalve, into a second operating position in which the said first outlet is isolated and the first and second inlets communicate with the said second outlet;

. an engine speed detector; and

. electronic control means for energizing the solenoid on the electrovalve when engine speed exceeds a first thresh old, and for de-energizing the said solenoid when the said speed falls below a second threshold lower than the first. A further characteristic of the supply system according to the present invention is that it also comprises a minimum throttle detector, and the said electronic control means are designed to close an auxiliary nozzle for supplying fuel into the intake pipe as the vehicle decelerates. Further characteristics and advantages of the present invention will now be described with reference to the attach ed drawings provided by way of a non-limiting example and in which :

- Fig.₁ shows a diagram of a supply system according to the present invention;

- Fig.₂ shows a detail of Fig.₁ in a different operating mode;

- Fig.₃ shows a section of the electrovalve on the Fig.₁ supply system.

[0003] Number 1 in Fig.₁ indicates the section of the intake pipe on an internal combustion engine located in the carburetor on the said engine.

[0004] The carburetor comprises known means (not shown) for supplying petrol from a main fuel tank into the intake pipe, and, in known manner, a throttle valve 2 for controlling the amount of-air supplied to the intake header on the engine.

[0005] The supply system according to the present invention comprises an auxiliary fuel tank 3 containing alcohol,. and means for supplying a mixture of air and alcohol to outlet pipe 4 on the said tank. As the said air and alcohol mixture is drawn in by the vacuum in the intake header, the said means may consist of the internal combustion engine itself. pipe ₄, in fact, is designed to be connected, as described in more detail later on, with the said intake pipe.

[0006] The auxiliary tank is provided with a pipe ₅ for receiving air from outside, the said pipe being fitted at the top end with a filter 6.

[0007] The system according to the present invention comprises an electrovalve 7 having a first inlet 8, communicating via pipe 9 with the inner cavity on the engine block so as to receive the oil vapour and gas coming from the said block, a second inlet 10, communicating via a non-return valve 11 with outlet pipe 4 on auxiliary tank 3, and a first and second outlet, ₁₂ and ₁₃, communicating respectively with the intake pipe on the engine up- and downstream from throttle 2.

[0008] _Electrovalve 7 comprises a moving member ₁₄, normally held by spring ₁₅ in a first operating position (Fig.₁) in which second inlet ₁₀ and second outlet ₁₃ are isolated and first inlet 8 communicates with first outlet 12. Under such conditions, the oil vapour and gas from the engine block are conveyed into the inlet pipe on the engine upstream from the throttle.

[0009] When solenoid 15 (shown schematically in Fig.₁) on electro valve 7 is energized, moving member 14 moves against the action of spring ₁₅ into a second operating position (Fig. ₂) in which first outlet 12 is isolated and inlets 8 and ₁₀ communicate with second outlet ₁₃.

[0010] Under such conditions, the air and alcohol mixture is supplied to the engine in addition to the air/petrol mixture and together with the oil vapour and gas from the engine block.

[0011] Number ₁6 indicates an auxiliary nozzle, in addition to the main nozzle (not shown) for supplying petrol into the inlet pipe on the engine. Nozzle ₁6, of known type, is controlled by solenoid ₁₇ which opens or closes it according to how the vehicle is running.

[0012] The system according to the present invention comprises an electronic control system having an engine speed detector ₁8 and a detector 19 for indicating when throttle ₂ is in the idling-engine position.

[0013] one end of solenoid ₁₅ is connected to positive pole ₂0 on the vehicle battery, whereas the other end is connected to a hysteresis threshold comparator ₂₁. The output signals from detectors 18 and ₁9 are also sent to an OR gate ₂₂, the input signals at the said gate having inverted logic levels in relation to the output signals from detectors 18 and 19.

[0014] The output on gate 22 is connected to the base of transis tor ₂₃ designed for grounding one of the two ends of solenoid 17.

[0015] The other end of the said solenoid is connected to the positive pole on the vehicle battery.

[0016] The system as described operates as follows.

[0017] As engine speed increases, solenoid ₁₅ remains de-energized until a first threshold, e.g. corresponding to a speed of ₁₂₀0 rpm, is exceeded, once the said threshold is exceeded, the solenoid is energized, so as to set electrovalve 7 as shown in Fig.2 and cause operation as already described.

[0018] As engine speed is reduced, solenoid 15 remains energized until the said speed falls below a second threshold lower than the first, e.g. 1200 rpm.

[0019] Solenoid ₁7 is normally energized (nozzle 16). It is de-energized during deceleration, i.e. when the throttle is set to minimum and speed exceeds the said second threshold, e.g. 1200 rpm, and is re-energized when the throttle is set to minimum and speed falls below ₁2₀0 rpm.

[0020] Fig.3 shows one arrangement of electrovalve 7. Number 24 indicates the electrovalve body consisting of a tubular element having inlet and outlet openings 8, 10 and 12, 13 on its side wall, and closed off at one end by plate ₂₅.

[0021] The other end of body 24 supports the armature 26 of solenoid 15 which comprises a moving core ₂7 connected by rod 28, made of non-ferromagnetic material, to moving core ₁₄ on the electrovalve.

[0022] To those skilled in the art it will be clear that changes can be made to the construction parts and arrangement described herein by way of a non-limiting example without, however, departing from the scope of the present invention.

Claims

₁) - Internal combustion engine supply system comprising a main fuel tank, a carburetor upstream from the engine intake header and complete with a throttle valve, and means for supplying fuel from the main tank to the carburetor, characterised by the fact that the said supply system also comprises :

. an auxiliary alcohol tank (3);

. means for conveying a mixture of air and alcohol from the auxiliary tank into an outlet pipe (₄) on the tank itself;

. a control electrovalve (7) having :

. a first inlet (8) communicating with the inner cavity on the engine block, for receiving the oil vapour and gas coming from the block;

. a second inlet (₁₀) communicating with the said outlet pipe (₄) on the auxiliary tank (₃);

. a first and second outlet (₁₂, ₁₃) communicating respec tively with the intake pipe on the engine up- and downstream from the throttle (₂); and

. a moving member (14) recalled elastically into a first operating position in which the said second inlet (₁₀) and said second outlet (₁₃) are isolated and the said first inlet (-8) communicates with the said first outlet (₁₂), provision being made for moving the said moving mem ber, by energizing the solenoid (₁₅) on the electrovalve, into a second operating position in which the said first outlet (₁2) is isolated and the first and second inlets (8, ₁₀) communicate with the said second outlet (13);

. an engine speed detector (₁8); and

. electronic control means for energizing the solenoid (15) on the electrovalve when engine speed exceeds a first threshold, and for de-energizing the said solenoid (₁₅) when the said speed falls below a second threshold lower than the first. ₂) - Supply system according to Claim 1, characterised by the fact that it also comprises a detector (₁₉) for detec ting the minimum position of the throttle (2), and that the said electronic control means are designed to close the auxiliary nozzle (₁6) supplying the fuel intake pipe from the main tank, during deceleration of the vehicle. All essentially as described and illustrated and for the purposes specified herein.

Drawing