Device for measuring the consumption of fuel in an internal combustion engine

Abstract: Device for measuring the consumption of fuel in an internal combustion engine, inserted in a feed system between a fuel tank (11) and an injection group (14), comprising a cup (15) provided with a level sensor (16) which controls the actuation of a suction pump (17) communicating with the fuel tank; said cup (15), fed by a pipe (20) coming from the suction pump and by a return pipe (13) coming from the injection group, is connected with the latter by a delivery pipe (12), and the suction pump (17), controlled by the level sensor (16), supplies the consumption data to a counter/totalizer device (23).

Description: The present invention relates to a device for measuring the consumption of fuel in internal combustion engines according to the preamble of claim 1, and known from document DE-A-3 732 293. GB-A-2 041 526 discloses a device for measuring the fuel consumption of internal combustion engines, particularly diesel engines, having a fuel injection system, which comprises an auxiliary fuel tank from which fuel feed and return lines lead to the engine and which is connected to the main fuel tank by a fuel line incorporating a volume meter. Furthermore devices for measuring the fuel consumption, of volumetric type, are known, which use turbines installed in the delivery pipes which feed the injection group, and in the return pipes from said injection group. Such devices compute the fuel consumption by difference and are generally used on vehicles and not in test rooms. Owing to the acceleration and deceleration inertias, the turbines may give non-reliable values owing to flow changes, and can be negatively influenced by the presence of air bubbles, in particular in the return pipe. Furthermore, such devices, owing to their using turbines, are definitively expensive. On the contrary, the devices known from the prior art which are used in test rooms, use fuel weighing systems and, owing to such a reason, are difficult to be installed on vehicles and hence are applied to an only limited extent. The purpose of the present invention is of providing a device for measuring the fuel consumption, which supplies reliable results, can be used both on board vehicles and in test rooms, and which, anyway, is easy to be installed, and, in the overall, can be manufactured in an economically advantageous way. In order to achieve such purpose, a device for measuring the consumption of fuel in an internal combustion engine is provided according to claim 1. In particular, the sensor measures changes in the level of fuel inside said cup, causing said suction pump to be actuated at any time when said level reaches a minimal value pre-calibrated on said sensor, and causes the operation of said suction pump to be discontinued at any time when said level reaches the maximum value pre-calibrated on said sensor. Still according to the invention, the level sensor can be a floating-body sensor, a capacitor sensor or an ultrasound sensor. According to a preferred form of practical embodiment according to the present invention, the suction pump is a gear pump with fixed displacement value. According to a further form of practical embodiment of the present invention, said suction pump and said impulse generator can be installed on said cup, to form one single unit with it. The technical characteristics and further advantages and features of the instant invention will be clearer from the following illustrative, non-limitative disclosure made by referring to the single accompaning figure, in which a schematic representation of the device of the present invention is shown. According to the figure, with the reference numeral 10 a device according to the invention is generally indicated, which is inserted in a fuel feed system for an engine, which system is constituted by a fuel tank 11, a delivery pipe 12 and a return pipe 13, and an injection group generally indicated with the reference numeral 14. The device 10 consists of a cup 15 equipped with a level sensor 16 which controls the actuation of an suction pump 17. The level sensor 16 is arranged inside a container having the shape of a cilindrical glass 18 with a much smaller volume than the cup 15, which cylindrical glass is facing towards the bottom of said cup. The suction pump 17 is in communication with the tank 11 through a suction pipe 19 and with the cup by means of the first inlet pipe 20; the pump, which is driven by a motor means 21 and the gear pump with constant delivery, is furthermore provided with an impulse generator device 22. The latter supplies the necessary impulses in order to increment a fuel consumption meter/totalizer device 23 connected with it. The suction pump 17 is actuated by means of the relay 24 connected with the level sensor 16. The delivery pipe 12 which feeds the injection group 14 is connected with the interior of the cup 15 and, downstream of said cup, it can be equipped with a priming device or an auxiliary pump, indicated with the reference numeral 25; the return pipe 13 from the injection group 14 constitutes, on the contrary, the second inlet pipe to the cup 15. The route along which the fuel flows from the fuel tank 11 to the injection group is indicated by the arrows 26, 27, 28 and 29, and the route in the return pipe 13 from the injection group towards the cup 15 is indicated by the arrows 30 and 31. The level sensor, which preferably is a level sensor of capacitor type, is so calibrated as to cause the suction pump 17 to start operating when the fuel level inside the cup 15 reaches a pre-estabilished minimum level. In the same way, the sensor is so calibrated as to discontinue the operation of the suction pump when the fuel level inside the cup reaches a maximum pre-estabilished level. When the pump is actuated, the impulse generator 22 supplies the consumption meter/totalizer device with necessary data to cause the latter to be incremented and to supply the required consumption data. In practice, a suitable calibration of the level sensor of very small differences between the minimum level and maximum level values will force the pump to operate in a quasi-continuous cycle mode. In this case, the device will supply instantaneous consumption data to the meter/totalizer device. Inasmuch as it is of a much smaller volume than the cup, the container with cylindrical glass shape 18 will also contain a reduced amount of liquid fuel, on which the level changes which may occur inside the cup due to slope changes of the road stretches the vehicle is running along, will be substantially with no effect. This feature and the structural simplicity make it possible the device according to the present invention to be adapted both in its static version, i.e., in test rooms, as well as on vehicles, without its reliability being impaired. Said structural simplicity makes it further possible to achieve reductions in costs, which are considerable relative to the measuring instruments Known from the prior art.

Claims: Device (10) for measuring the consumption of fuel in an internal combustion engine, inserted in a feed system constituted by a fuel tank (11), delivery and return pipes (12, 13) and an injection group (14), said device (10) comprises a cup (15) provided with a level sensor (16) which controls the actuation of a suction pump (17) communicating with said fuel tank (11), said cup (15) being connected at its inlet side with a pipe (20) coming from said suction pump (17) and with a return pipe (13) coming from said injection group (14), and, at its outlet side, being connected with a delivery pipe (12) which feeds said injection group (14), said suction pump (17) being provided with impulse generator means (22) suitable for incrementing a fuel consumption meter (23), characterised in that said level sensor (16) is arranged inside a glass-shaped container (18) facing towards the bottom of said cup (15), said container (18) having a much smaller volume than said cup (15) and being capable of containing a fuel amount with an essentially constant level relatively to said cup (15). Device (10) according to claim 1 charaterized in that said level sensor (16) measures variations in the level of fuel inside said cup (15), causing said suction pump (17) to be actuated at any time when said level reaches a minimal value pre-calibrated on said sensor (16), and causes the operation of said suction pump (17) to be discontinued at any time when said level reaches the maximum value precalibrated on said sensor (16). Device (10) according to claim 1, characterized in that said level sensor (16) is a floating-body sensor. Device according to claim 1, characterized in that said level sensor (16) is a capacitor sensor. Device (10) according to claim 1, characterized in that said level sensor (16) is a ultrasound-sensor. Device (10) according to claim 1, characterized in that said suction pump (17) is a gear pump with fixed delivery value. Device (10) according to claim 1, characterized in that said suction pump (17) and said impulse generator (22) can be installed on said cup (15), in order to form one single unit together with said cup (15).

Inventors: GANDINI ROBERTO, GANDINI, ROBERTO
Applicants: GANDINI ROBERTO, GANDINI, ROBERTO
Application year: 1991
Main classification: G01F9
IPC codes: G01F9