Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1993-03-16
1994-03-29
Dolinar, Andrew M.
Internal-combustion engines
Charge forming device
Fuel injection system
123493, F02D 4110
Patent
active
052975258
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a method for determining the quantity of fuel injected for an internal combustion engine in dynamic transition operation.
In dynamic transition operation, such as, for example, acceleration or overrunning, a basic quantity of fuel to be injected must be increased or reduced in relation to the conditions in the steady-state operating condition. For this purpose, a correction quantity of fuel injected is used, this being determined by first of all determining a base quantity from the load and speed. This base quantity is in each case differentiated in order thereby to evaluate the degree to which the operating condition has changed. Finally, filtering is also carried out, in order to simulate the filling of the suction pipe, the build up and decay of the wall film and to compensate disturbing influences. The differentiated base quantity is here subjected as a filter input variable to a filter characteristic which contains various filter constants. These filter constants are determined experimentally and are constant.
In road tests, it has been ascertained that correction quantities of fuel injected determined in this way are in some cases too small or too large by a multiple of their order of magnitude. Moreover, they are strongly dependent on the operating point and the method is only designed for a warm engine.
FR-A-21 63 241 discloses an electrically controlled fuel injection device for internal combustion engines, in which pulsations of the air quantity signal are smoothed out with the aid of a filter.
PCT reference WO-A-88 02 811 (corresponding to U.S. Pat. No. 4,924,835) discloses the filtering of the output signals obtained from various operating parameters; likewise in order to smooth out pulsations. The filtering inevitably results in a delay in the event of a change in the signal. In order to match the said signals to the particular situation, the filter characteristic is in both cases made dependent on parameter changes. No alteration is made to the magnitude of the signal.
SUMMARY OF THE INVENTION
The object of the invention consists in specifying a method of the type stated at the outset which always supplies correction quantities of fuel injected which are as accurate as possible.
According to the present invention the object is achieved by a method for determining the quantity of injected fuel for an internal combustion engine during dynamic transition operation, in which a correction quantity of injected fuel is determined and the normal basic quantity of injected fuel is increased or decreased by this amount. The correction quantity of injected fuel is obtained from a base quantity determined from load and speed by a procedure. In the procedure the base quantity is differentiated and subjected to filtering in accordance with a filter characteristic with at least one filter constant, wherein the filter constant is dependent on operating parameters of the internal combustion engine.
The following are advantageous developments of the present invention. In one embodiment the filter constant is chosen differently depending on whether the differentiated base quantity, that is the filter input signal, is positive or negative. In each case the filter constant is dependent on the speed. In another embodiment the filter constant is multiplied by a correction factor which is chosen differently depending on whether the differentiated base quantity is positive or negative. In each case the filter constant is dependent on the cooling water temperature. The correction factor is furthermore chosen differently depending on whether or not the engine is idling.
The invention is based on the realization that it is the use of fixed filter constants which cause the inaccuracies in the determination of the correction quantity of fuel injected. Sufficient accuracy is, on the other hand, achieved if use is made of variable filter constants which are dependent on operating parameters of the internal combustion engine. The dependence on the operating point is th
REFERENCES:
patent: 4010717 (1977-03-01), Taplin
patent: 4924835 (1990-05-01), Denz
Krebs Stefan
Miener Bjorn
Dolinar Andrew M.
Siemens Aktiengesellschaft
LandOfFree
Method for determining the quantity of fuel injected does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for determining the quantity of fuel injected, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for determining the quantity of fuel injected will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-785380