SE451904B - PROCEDURE AND DEVICE FOR MANUFACTURING DECISION BASIS FOR CHOOSING FUEL ECONOMIC VIEW FAVORABLE OPERATING CONDITIONS FOR EXPLOSION ENGINE DRIVES - Google Patents

Description

451 904 l In addition, a proportion of the fuel's energy content has been used to change the car's movement and positional energy.

This energy has not yet been consumed, only converted from chemical to mechanically stored energy that is available to roll the car without additional fuel consumption.

In cases where it is possible to select operating parameters (eg by selecting different gears or by switching to other temporarily storable energy types), an indicator showing the actual losses provides the opportunity to correct operating conditions so that the efficiency is the best possible. Consumed energy for a given utility function (eg transport distance) is calculated as consumed fuel less the part of temporarily stored energy of any other kind that can be used for utility functions. The conversion factor between fuel quantity and stored energy is chosen, for example, for what corresponds to the best efficiency of the engine and the transmission. xnf. The object of the invention is to present to the driver at any moment such information which is of good guidance in the selection of such operating parameters for the engine that considerable fuel savings can be achieved under varying driving conditions. The data that is best suited to provide guidance in the selection of the operating parameters consists of an estimate of the total energy consumed per road section traveled.

The desired result is obtained by a method according to claim 1 or a device according to claim 7.

An embodiment of the invention is described in more detail below with reference to the accompanying drawings. Fig. 1 shows a principle example of the specific fuel consumption (g / kWh) of a typical petrol engine as a function of speed and torque. The data for this figure is taken from ref 1 for the principal appearance and from ref 2 for the actual numerical values in a few points.

Fig. 2 is a schematic representation of sensors, data paths, actuators, calculation unit and display means according to the present invention.

The principle of the method according to the invention is that sensors collect data about the vehicle's internal and external variables, these are processed in a calculation unit and the result, consumed energy per distance traveled = IND, is presented on an indicator for the driver.

The recalculation relationship is reported in Equ. / s - K2-Z- (n1 - nO) / s - K6 ........

IND is the indicator reading presented to the driver s is during the measuring interval traveled distance B is during the measuring interval to the carburettor or equivalent delivered fuel e. b is during the measuring interval in the carburettor temporarily stored fuel (eg in the acceleration pump) K2 is the conversion factor between mechanical energy and fuel quantity 451 904 few m is the total mass of the vehicle, possibly increased by a virtual mass corresponding to the moment of inertia of the wheels.

A is the acceleration of the vehicle plus the component of the ground acceleration in the road plane. In a simplified procedure and in certain applications, the component of the ground acceleration can be omitted, thereby neglecting the potential energy of the vehicle. In this case, term 2 is more easily calculated according to the formula KZ- (vïz -vÜU m / 2.

K3 is a function of battery voltage etc, and includes charge efficiency and conversion factor U is battery voltage.

I is battery charging current. t is the measuring interval in time H is the summed inertia moment of the wheels etc. v1 is the speed of the vehicle at the end of the measuring range. v0 is the vehicle speed at the beginning of the measurement interval.

Z is the moment of inertia of the rotating parts of the engine. n1, the motor speed is the end of the measuring range. n0 is the engine speed at the beginning of the measurement interval.

Term 1 is the conventional consumption.

Term 2 gives the change in the sum of potential and kinetic energy per distance traveled (in some cases the potential energy can be neglected).

Term 3 years in the battery stored energy per distance traveled. This term can in many cases be neglected, but where it is important, the battery's charge susceptibility and efficiency must be taken into account.

Term H Change in kinetic energy per distance traveled in the form of rotational energy in wheels, etc. Can often be approximated by adding a virtual mass to the vehicle's total mass m. When reversing, this approximation gives an error contribution which can usually be neglected.

Term 5 Change in rotational energy of the rotating parts of the engine per distance traveled. To the extent that this stored energy could propel the vehicle forward without additional fuel supply, it must be included. Normally the engine has such a large internal friction that the engine instead has a braking effect, which is why the term is not included.

Term 6, etc. Additional forms of energy stored in the interval that can later be utilized, thereby saving fuel.

For an embodiment according to claim 7, it is chosen to include terms 1, 2 and 3 in the calculations. Term U is approximated by a virtual mass which is added to the mass of the vehicle.

The fuel flow to the engine is measured by the fuel gauge 1 which generates binary electrical pulses, where each pulse represents a certain quantity of fuel, of the order of 0.1 ml. 451 904 4 Calculation unit 2 contains registers of which register Ä is used to accumulate the total number of fuel pulses 3, and register 5 is used to count incoming fuel pulses 3 during the measuring range. - Mileage is measured with a magnetic or optical sensor 6 mounted between the speedometer cable and the speedometer. The sensor 6 emits a binary electrical path pulse 7 each time a tooth on a gear mounted on the speedometer cable is passed. Each road pulse 7 represents a distance traveled ds. The road pulses 7 are accumulated partly in total in register 8, and partly the road pulses 7 incoming during a measuring interval are accumulated in register 9, all in calculation unit 2.

Accelerometer 10 is mounted and adjusted so that it only measures the acceleration along an axis parallel to the ground plane and along the longitudinal axis of the vehicle. The output signal 11 from accelerometer 10 is a binary coded 8 bit word including characters.

Each time a path pulse 7 arrives at the calculation unit 2, the accelerometer signal 11 is read and added to the contents of register 12 in the calculation unit 2.

For a correct calculation of spent fuel, correction must be made with the amount of fuel contained in a possible acceleration pump. A position sensor 13 is mounted on the pump which converts the position of the pump diaphragm into a binary signal 1U with a H-bit resolution. The position of the pump diaphragm is read by the calculation unit 2 at the end of each measuring interval.

Register 18 in the calculation unit 2 is a real-time clock that is used for control.

For selection of programs in the calculation unit 2 and for input of current parameters, a control panel 15 is connected to the calculation unit 2.

Indication of the selected program takes place via signals from the calculation unit 2 to a number of indicator lamps 16.

The results of the calculations that take place in the calculation unit 2 are presented in the form of figures on the digital presentation unit 17.

The calculation unit can have several different programs. When starting up the system, any changes to calculation parameters can be entered in the intended registers through a special program that is selected with control panel 15. The parameter that may need to be adjusted often is the total weight of the vehicle, which of course varies with the load. The weight is adjusted, for example, by a number corresponding to the deviation from a normal weight. The time interval dt x 2 ”sec of the measurement interval is also specified with the exponent n which is entered in a register 20. The measurement interval is calculated and entered in register 19.

In the following, however, only the principle of the program that calculates the instantaneous total energy consumption per km driven shall be described.

At start-up, the interval time 19 is copied to register 18.

This register is then counted down by a divided clock pulse every dt sec.

At start-up: register H for the total number of fuel pulses, register 5 for the number of fuel pulses during the interval, register 12 for accumulated acceleration, register 8 for the total number of road pulses and register 9 for the number of road pulses during the measuring interval.

R 4bà 904 ~ x Now the measuring interval begins and below this the fuel pulses 3 in registers H and 5 are counted, the road pulses in registers 8 and 9. For each time pulse received, register 18 is stepped down one unit and added - the acceleration signal 11 to the accumulated value in register 12 In addition, register 18 is tested. If it is equal to zero, the calculation and presentation cycle must begin.

Otherwise, the collection phase continues, whereby fuel pulses 3, road pulses 7 and time pulses are registered.

The calculation and presentation cycle begins with register 18 becoming zero. Then the next fuel pulse is expected, while road pulses are also registered. This eliminates the quantization error that could otherwise be significant due to a fairly large amount of fuel per pulse. By selecting such a small ds that the number of road pulses during the measurement interval becomes sufficiently large, the road quantization error can be reduced to a sufficient degree in relation to other uncertainties and the desired accuracy. When the expected fuel pulse has been received, the desired information is in the calculation unit's register and the desired estimate of energy consumption per km is obtained by calculation according to eq.1, after which the numerical value of the energy consumption is output to the indicator unit 17 and may remain there during subsequent calculation intervals. This calculation interval begins with the affected registers being initialized to their initial values as above and the cycle repeated.

Example: During a rapid acceleration when the engine operates at 70% -90% of maximum torque, the engine has its best efficiency, ie the largest possible proportion of the fuel's energy content is converted to mechanical work at the drive wheels. Of this mechanical work, the bulk of the ag is needed to increase the vehicle's kinetic energy and remains. The proposed invention would indicate a relatively low energy / km consumption, as it takes into account that a large part of the spent fuel is converted into kinetic energy stored in the vehicle and which is available to propel the vehicle forward without consuming additional fuel. A conventional fuel consumption meter would show a very large fuel consumption / km during the acceleration phase. If we use the conventional fuel consumption meter to drive "cheaply", we are led to instead accelerate the vehicle very slowly, whereby the fuel consumption meter shows a low deflection (while the invention will show a higher deflection than in the first case).

Under these conditions, the engine operates only with low partial load and therefore has poor efficiency. Only a small part of the energy content of the fuel has been converted into useful mechanical work at the drive wheels. That is, for a certain amount of useful work performed, more fuel has been consumed than in the first case when the engine had to work with the best efficiency. This example indicates that the information from the proposed invention allows the driver to choose such a driving mode (gear, throttle, etc.) that the engine operates under such conditions that it converts as much as possible of the energy content of the fuel into useful mechanical work. 451 904, The required correction of the values from a conventional fuel consumption meter, in order to obtain the energy consumption, can be significant. For example, a data simulation of the invention applied to a Saab 95 shows that at almost full acceleration on His gear, a conventional fuel consumption meter at 80km / h shows about 1.1 liters / mile while the invention would show about 0.5 liters / mile. The correction for kinetic energy is apparently significant. Simulation of take-off processes up to 50 km / h shows 25% variation in spent fuel over a distance of '00 m in different driving strategies and that driving strategy based on the invention gives low consumption. According to the invention, such information is thus obtained that the person operating the engine can choose such operating conditions for the engine that a considerable fuel saving is achieved. lf;

Claims (1)

.pl. PATENT REQUIREMENTS 1) Procedure for motor vehicles for the production of such a decision basis that gives the driver the opportunity to choose such operating parameters for engine and vehicle under dynamic driving conditions that a fuel saving is made possible, where the decision basis is obtained by processing incoming measurement signals in a calculation unit. unit of calculation calculated value of instantaneous energy consumed per unit of length driven, characterized in that during a measuring interval the distance traveled is measured, that during the same measurement interval fuel delivered to the engine is measured, whereby a first approximation of the vehicle's instantaneous energy consumption per driven length unit is calculated. speed change in the direction of travel is measured whereby by calculation a calculation of the kinetic energy stored or delivered in the vehicle is obtained, that the measured values are supplied to a calculation unit (E), that the calculation unit is arranged to reduce or increase it by fuel quantity the measurement obtained the first approximation of momentarily consumed energy per unit of length driven with a term corresponding to the calculation made from the speed change measurement of the kinetic energy stored in the vehicle per delivered unit of length. Method according to claim 1, characterized in that during the same measuring interval the height gain of the vehicle is measured, whereby a calculation of potential energy stored in the vehicle is made, that the measured values are supplied to the calculation unit (E), that the calculation unit is arranged to decrease or increase according to claim 1. the calculation of instantaneous energy consumed per unit of length driven with a term that corresponds to the calculation of the potential energy stored in the vehicle stored or delivered per unit of length made by the measurement of the vehicle's height gain. Process according to Claim 1, characterized by. that during the measuring interval the vehicle's acceleration in the direction of travel plus the ground acceleration component in the road plane parallel to the direction of travel is measured, whereby by appropriate treatment a calculation of in the vehicle during the measuring interval stored or emitted sum of kinetic energy and potential energy is obtained, that the measured values are added. That the calculation unit is arranged to reduce or increase the first approximation of momentarily consumed energy per driven length unit obtained by the fuel quantity measurement with a term corresponding to the calculation made from the acceleration measurement of the sum of kinetic energy and potential energy per driven length stored during the measuring interval in the vehicle. 4) Method according to one of the preceding claims, characterized in that during the measuring interval the changes in stored fuel between the fuel quantity sensor and the engine cylinders are measured, that the measured values are supplied to the calculation unit CE), that the calculation unit is arranged to correct the calculated torque. with a term corresponding to the amount of fuel stored or delivered per unit of length driven between the fuel quantity sensor and the engine cylinders. 5) A method according to any one of the preceding claims, characterized in that during the measuring interval the charge amount and battery voltage carried to or from the vehicle's accumulator batteries It is measured that the measured values are supplied to the calculation unit (E), that the calculation unit is arranged to reduce W; respectively, increase the calculated instantaneous energy consumption per unit of length driven by a term that corresponds to the calculation made of the batteries' charge supply and voltage made of per unit of length stored and delivered electrical energy in the batteries. Device for carrying out a method according to claim 1, characterized in that it comprises a timer, that it comprises a sensor (6) from which the distance traveled can be calculated, that it comprises a sensor (1) from whose signal the fuel flow to the engine can be calculated. that it comprises sensors (1Ü or 6) from whose signal the speed change of the vehicle can be calculated, that it comprises means for transmitting the sensor signals to a calculation unit (E) that the calculation unit (E) is arranged to calculate starting from the above-mentioned sensor signals during each food interval of the vehicle's consumed 'amount of energy per unit of length driven, where consumed energy is calculated as consumed fuel energy decrease or increase with in the vehicle in the form of kinetic energy stored and released energy. m! ä) ~~ 451 904 k.) 7) Device for execution according to claim 6, characterized by. that it also comprises sensors (IÜJ from whose signal the vehicle's acceleration plus the ground acceleration component in the road plane parallel to the direction of travel can be calculated, that calculation unit (E) is arranged to calculate from each of the above sensor signals during each measurement interval the vehicle consumed Consumed energy is calculated as consumed fuel energy reduced or increased with stored in the vehicle, respectively given amount of kinetic energy and potential energy. '\ J 8) Device according to claim 6 or characterized in that it also includes sensors from whose signal changes in the energy in the electrical the accumulator batteries can be calculated, that it comprises means for transmitting the sensor signals to a calculation unit (2), that the calculation unit (E1 is arranged to correct the sensor signal according to claim 6 or 7 during each measuring interval calculated by the vehicle consumed energy amount per driven length a term that corresponds against the change per unit length driven of the energy content of the batteries. Device according to Claim 6, 7 or 8, that a presentation device (17) of analogue or digital type is connected to the calculation unit (E), that it shows the resulting calculation of energy consumed during the measuring interval per unit of length driven. References: 1. AIP Conference Proceedings no 25 Efficient use of Energy fig 4.3 E. Repair manual for Saab 95.