DE2440398A1 - Measurement of instantaneous fuel consumption - designed for injection combustion engines in vehicles, ships and aircraft - Google Patents

Abstract

Arrangement for measurement of fuel consumption in injection combustion engines comprises a control source (1) which issues signal (U1) proportional to the fuel injected per cycle in a combustion engine. This signal (U1) is fed into a circuit in which it is multiplied by a value proportional to the spaced and/or gear ratio of the engine and the output from the circuit is fed into an indicator (6) of fuel consumption of the engine. The control source (1) is an adjustable resistance connected across a constant voltage supply (U-const.) whose slide (2) is coupled to the injection pump adjusting arm (3). The circuit with indicator comprises a resistance (Rv) which is preceded by an auxiliary resistance (RV1-RV4) selectable depending on the gear ratio.

Description

Device for measuring instantaneous fuel consumption The invention relates to a device for measuring the instantaneous fuel consumption for injection internal combustion engines, especially in motor vehicles, airplanes and ships.

For drivers of motor vehicles it is of interest to know the current Knowing fuel consumption in liters per 100 km, for example in order to drive economically to be able to or to recognize faults in the engine. On the other hand, drivers of ships and airplanes are interested in the fuel consumption in liters per hour for the same reasons.

Flow meters are known, e.g. B. for fuel pumps, which are driven by the flow velocity of the flowing liquid are, however, in such small amounts as in an automotive internal combustion engine are consumed, can no longer be used. Also flow meters with heated semiconductors are far too imprecise in simple designs with these small flow rates.

It is the object of the invention to provide one for injection internal combustion engines simple device to indicate which the task at hand with sufficient accuracy fulfilled.

This object is achieved in that a controlled variable Qeber is provided is the one proportional to the fuel consumption per duty cycle of the internal combustion engine Size supplies which can be fed to a circuit in which it is connected to one of the Motor speed or the value assigned to the gear ratio multiplied and that the output of this circuit is the instantaneous fuel consumption is proportional and can be displayed in a measuring instrument.

For diesel engines or gasoline engines with mechanical fuel injection the injection quantity per working cycle of all cylinders is proportional to the position the control rack on the injection pump, in engines with electronic injection it is proportional to the duration of the injection pulse.

The current consumption per unit of time results from Vt = VZ. nM. C1 with Vt = consumption per unit of time V = consumption per work cycle Z nM = Motor speed cl = dimensional constant It can be in liters per minute or in liters per hour.

If the current consumption per distance is to be determined, then is the driving speed vF must be taken into account.

vF = 21t R. nR = C. n 2 R with R = wheel radius nR = end speed c2 = dimensional constant The wheel speed nR and the engine speed nM have a fixed ratio to one another in a gearbox between the two shafts, which changes from gear to gear in multi-step gearboxes.

u = transmission ratio The current consumption per distance V5 is then = V5 = VZ. ü. C3 c3 = dimension constant 3 In the case of mechanical injection pumps, provision is made for the control variable generator to be a variable resistor, the tapping of which can be adjusted by the control rod of the injection pump that determines the injection quantity. In an exemplary embodiment preferred by the invention, this variable resistance is connected to a constant reference voltage. The circuit following the control variable transmitter and connected to the tap and the measuring instrument consist of a voltmeter with a series resistor.

To determine the current fuel consumption per route is each gear ratio of the gear following the internal combustion engine a series resistor is assigned, which can be switched on when the corresponding gear is engaged is.

To determine the current fuel consumption per time, it is provided that the series resistor is a controllable resistor whose resistance value depends can be changed by the engine speed.

For practical use it is advantageous when the measuring instrument a threshold switch with a variable, based on a certain instantaneous fuel consumption adjustable threshold is assigned, when exceeded an acoustic and / or optical signal can be emitted.

The invention is based on a schematic AusfUhrungs example shown in more detail in the drawing. It describes a device for measuring the current fuel consumption in liters per 100 km for a motor vehicle with a Manual transmission with four forward gears.

A potentiometer 1 working as a control variable encoder is connected to one Stabilized voltage derived from the vehicle battery voltage + UCOnst. The tap 2 of this potentiometer is with the control rod of the indicated fuel injection pump 3 connected and provides a fuel consumption per duty cycle Vz proportional Voltage U1. This arrives via a switch 4, which is controlled by an indicated gear position transmitter 5 is actuated, to one of the four series resistors Rvi bis assigned to the gears Rv4 and the measuring instrument 6 with the internal resistance Rg. Series resistor and measuring instrument form a voltage measuring circuit for the voltage U with Ul = n.Ug.

If this formula is given by Vs = Vz. ii. Replaces C, we get 3 VZ = U1, VS = Ug, Ü. C3 = n With this and with R 5 R (n - i) the value of the series resistors v g can be calculated. The scale of the measuring instrument 6 can directly show 1/100 km.

An adjustable threshold switch is located parallel to the measuring instrument 6 7, which emits an acoustic signal when the set voltage is exceeded a signal generator 8 emits.

However, the invention is not limited to this exemplary embodiment, but can also be implemented by other means, e.g. B. in digital technology with coded transmission of the gear position or with a multiplier circuit in analog technology.

Claims (7)

A n s p r ii c h e 1. Device for measuring the instantaneous fuel consumption Injection internal combustion engines, especially in motor vehicles, airplanes and ships, characterized in that a controlled variable encoder (i) is provided, which is one of the Fuel consumption per working cycle of the internal combustion engine proportional size (U1) supplies which can be fed to a circuit in which it is connected to one of the The value assigned to the engine speed or gear ratio is multiplied and that the output variable (U) of this Cchalttmg corresponds to the current fuel consumption is proportional and can be displayed in a measuring instrument (6). 2. Apparatus according to claim 1, characterized in that the controlled variable transmitter (i) is a variable resistor, the tap (2) of which is connected to the injection valve The control rod of the injection valve (3) that determines the control rod can first be set. 3. Apparatus according to claim 2, characterized in that the Vereinderhtrc thin Resistance (1) is at a constant reference voltage (Uconst). 4. Device according to one or more of the preceding claims, characterized in that the following on the controlled variable transmitter (i) and at the tap (2) connected circuit and the measuring instrument (6) from a voltmeter with series resistor (Rv). 5. Apparatus according to claim 4, characterized in that each Gear ratio (ii) of the transmission following the internal combustion engine Series resistor (Rv1 to Rv4) is assigned, which when inserting the corresponding Ganges can be switched on. 6. Apparatus according to claim 4, characterized in that the series resistor is an adjustable resistor, the resistance value of which depends on the engine speed is changeable. 7. Device according to one or more of the preceding claims, as characterized1 that the measuring instrument (6) has a threshold switch (7) a variable, adjustable to a specific instantaneous fuel consumption Threshold is assigned, when exceeded an acoustic and / or visual Signal can be emitted.