| 摘要 |
The efficiency of practical engines for transportation varies strongly with RPM and powerlevel. Under dynamic driving conditions, that is to say with speed-changes and hilly roads, there are good possibilities to adjust the way of driving so that the mileage is influenced. The principle of measuring and presenting the fuel used per driven distance is known. Such a device usually gives information that is at best difficult to use and sometimes directly missleading under dynamical driving conditions. The explanation is, that the meter only registers the used fuel-energy and does not take into consideration the energy that has been stored e.g. in the form of increased speed of the vehicle, and which can be used later for propelling the vehicle. In the proposed invention the instantaneously measured fuel consumption per driven unit of length is corrected with different forms of stored energy per driven unit of length. This gives a measure of at every moment used total-energy per driven unit of length. Presented to the driver, this gives a good guidance for choice of a way of driving which results in considerable fuel saving. In one embodiment of the invention the energy-consumption is calculated as, by flowmeter (1) measured flow of fuel to the engine from which is subtracted terms corresponding to the potential and kinetic energy stored in the vehicle. The data for the stored energy is calculated from data from accelerometer (10) which measures the acceleration of the vehicle plus the component of the earth's gravitation that is parallel to the road surface. The signals from relevant sensors are treated in processing unit (2) and the resulting value of the instantaneous energy-consumption per driven unit of length is presented on display unit (17) for the driver. |
