Abstract: This invention relates to a method for knock detection in a combustion engine, in which combustion is controlled by a control unit (2), which comprises the steps of, a) obtaining at least one sensor signal (4, 4?) carrying information of knock intensity related within a combustion chamber of the combustion engine (1); (b) processing the sensor signal (4, 4?) to obtain a knock intensity related detection variable (z1), (c) using said detection variable (z1) in said control unit (2) arranged to avoid a knocking condition in said combustion engine (1), if the value (z1) of said detection variable indicates knock when compared with a threshold value (T) wherein using two different computations/processes for said processing (5, 6) of the at least one sensor signal (4, 4?) to obtain two separate sub-values (y1, y2), and thereafter combining said sub-values (y1, y2) to obtain said detection variable (z1).

Abstract: This invention relates to a method for knock detection in a combustion engine, in which combustion is controlled by a control unit (2), which comprises the steps of, a) obtaining at least one sensor signal (4, 4?) carrying information of knock intensity related within a combustion chamber of the combustion engine (1); (b) processing the sensor signal (4, 4?) to obtain a knock intensity related detection variable (z1), (c) using said detection variable (z1) in said control unit (2) arranged to avoid a knocking condition in said combustion engine (1), if the value (z1) of said detection variable indicates knock when compared with a threshold value (T) wherein using two different computations/processes for said processing (5, 6) of the at least one sensor signal (4, 4?) to obtain two separate sub-values (y1, y2), and thereafter combining said sub-values (y1, y2) to obtain said detection variable (z1).

Abstract: This invention relates to a method in connection with engine control, wherein a combustion feedback signal is derived by measuring one or more combustion related parameters during a chosen time period of a first combustion cycle, for control of a possible fault, wherein at least one reference feature for said parameters has been determined previously, and comparing said measured combustion feed back signal with said reference feature for automatic adaptation of at least one combustion related variable during a forthcoming combustion cycle wherein at least one reference features for each one of at least two different fault situations having been determined previously, and that a diagnosis 3 of said first combustion cycle is performed on the basis of said combustion feedback signal being processed and compared (T1-Tn) with each one of said reference features, the result of which is analysed by a decision logic, whereafter a diagnosis (D) is established by means of which one or more variables in a forthcoming co

Abstract: This invention relates to a method in connection with engine control, wherein a combustion feedback signal is derived by measuring one or more combustion related parameters during a chosen time period of a first combustion cycle, for control of a possible fault, wherein at least one reference feature for said parameters has been determined previously, and comparing said measured combustion feed back signal with said reference feature for automatic adaptation of at least one combustion related variable during a forthcoming combustion cycle wherein at least one reference features for each one of at least two different fault situations having been determined previously, and that a diagnosis 3 of said first combustion cycle is performed on the basis of said combustion feedback signal being processed and compared (T1-Tn) with each one of said reference features, the result of which is analysed by a decision logic, whereafter a diagnosis (D) is established by means of which one or more variables in a forthcoming co

Abstract: An arrangement and a process for communication between an ignition module (ICM) mounted on an engine and a control unit (ECM). The ignition module includes detection circuits and signal processing stages in order to determine at least one combustion related parameter from detected ionization currents in the combustion chamber (22). The control unit (ECM) communicates with the ignition module via at least one bi-directional communication wire (K.sub.CQ or K.sub.KI). Via the communication wire the control unit activates the detection in the ignition module, and the ignition module sends a signal corresponding to the magnitude of the detected parameter to the control unit on the same communication wire. Activation and transfer of parameter data is conducted sequentially over the communication wire.

Abstract: A method for sorting out false indications of a knocking condition in combustion engines, and in a close loop manner influencing the control measures initiated in order to cease the knocking condition, which method includes obtaining an ionization signal characteristic of the ionization during a combustion with the aid of a gap biased by a measuring voltage and arranged in the combustion chamber. A knocking condition is detected from the determined intensity of the knock characteristic frequency content (KI) filtered out from the ionization signal. An integrated value (CQ) of the ionization signal is also used in order to influence knock control measures. Knock control measures are initiated at a first spontaneous knocking condition only if also the integrated value (CQ) from a combustion experiencing a knocking condition is increased in relation to a preceding non-knocking combustion (CQ.sub.REF.sbsb.--.sub.NORM). Further, the speed of return (KT.sub.STEP, Ign.sub.RET.sbsb.--.sub.

Abstract: A method and system for controlling combustion engines by detection of the present air/fuel ratio within the cylinders of the combustion engine, using an analysis of the characteristics of the ionization current, as detected via a measuring gap with a bias voltage applied being arranged in the combustion chamber, preferably using the spark plug gap in an Otto-engine. A measuring voltage corresponding to the degree of ionization is detected during the flame ionization phase and during a time- or crankshaft position dependent period A, B, C or D, which duration is dependent of the present air/fuel ratio, and will be finished by an amplitude maximum PF during the flame ionization phase. A parameter characteristic for the fundamental frequency of the measuring voltage during the period A, B, C or D is detected, which parameter indicates a tendency towards the rich direction of stoichiometric when the fundamental frequency increases, and inversely indicates lean tendency when the fundamental frequency decreases.

Abstract: An improved method applied in combustion engines which use the ionization current in the combustion chamber in order to extract a parameter representative of the pressure in the cylinder, which parameter is used for controlling the ignition timing within an extended range for the load- and speed range. The method is based on an integration of a parameter dependent on the ionization current. In a first embodiment, the mass center position of the integral is calculated, which mass center position is used as a position corresponding to the peak pressure position. The ignition timing is adjusted in such a manner that the mass center position, and hence the peak pressure position, strives to obtain a predetermined target value. In a second embodiment, an integrated value is calculated, which take into account the mechanics of the combustion engine, in such a way that the integrated value corresponds to a value representative of the torque transmitted to the crankshaft.

Abstract: A method and system for adaptive correction of the amount of fuel supplied in two-stroke combustion engines which during a continuous operation period regulates the air-fuel mixture regulated by increments in the lean direction (.DELTA.F.sup.-) or in the rich direction (.DELTA.F.sup.+), whereby fuel amounts (F) are established which cause knocking (KNOCK) and four-stroking or misfiring (4-ST), respectively. These limit values are stored as a lean limit value M.sub.FK and a rich limit value M.sub.F4ST, respectively. For further operation of the combustion engine, a corrected fuel amount F.sub.koor, is used, which is corrected in relation to the fuel amount F.sub.tab given from an empirically determined value stored in a map, and dependent on the established lean limit value M.sub.FK and the rich limit value M.sub.F4ST, respectively. The fuel amount (F) supplied will suitably be given according to the function: F=F.sub.korr =M.sub.FK +K.multidot.(M.sub.F4ST -M.sub.

Abstract: An arrangement and method for regulation of idle speed and charge pressure in a supercharged combustion engine (1) which engine includes an idle speed valve (20) arranged in a shunt channel (21) by-passing the throttle (9) and a gate valve (10) regulated by a pressure controlled diaphragm pot for regulating of the supercharger. The valve (20) is used both for regulation of idle speed and charge pressure by an arrangement of ducting (23, 24, 25, 19) and a shut-off valve (26). A control device (31) includes different functions for regulation of idle speed and charge pressure. The function selected for regulation by the control device depends on an engine parameter, such as throttle position, detected by a throttle position sensor (16).

Abstract: The invention relates to a method and arrangement for cleaning the spark plugs of an internal combustion engine automatically subsequent to the engine stopping and then, preferably, after an unsuccessful attempt to start the engine. Consequently, conditions for a successful starting attempt are made more favorable. Conditions preventing the start of an engine are often due to the presence of deposits on one of the spark plugs, these deposits preventing an ignition spark from being produced in the cylinder. The inventive method and arrangement solve this problem by burning clean the spark plugs immediately after the engine has stopped, and then preferably after the engine has failed to start. A detection means establishes whether or not the engine has started by sensing a suitable engine parameter, preferably engine speed, through a speed indicator.

Abstract: The invention relates to a method for achieving elevated charging of an ignition capacitor in a capacitive type ignition system for internal combustion engines. When starting a cold engine or when starting the engine under other conditions in which the battery capacity is low, activation of the engine starting motor will result in a drop in voltage in the electric system serving both the starting motor and the ignition system. The voltage drop in the electrical system will vary sinusoidally synchronously with the crankshaft rotation, owing to the fact that the starting motor will momentarily subject the electrical system to higher loads when the pistons are located adjacent their top-dead-center position L in the compression stroke. The method solves this problem, by delaying the re-charging of the capacitor until a position is reached in which the voltage drop in the electrical system has its lowest value.

Abstract: The invention relates to a method and an arrangement for improving the starting ability of an internal combustion engine during difficult engine starting conditions that result from cold weather or other external circumstances. Lower than normal engine starting speeds can occur during cold weather, for example. So as not to hinder an engine start, it is essential that the spark plugs be free from deposits and in their best condition. This is achieved by burning off any deposits present on spark plugs during an engine start attempt, when difficult engine starting conditions are detected. During an engine start attempt a comparison circuit ascertains whether or not one or more detected engine parameters have a lower value than in normal engine starting conditions. The comparison circuit sends a signal to the control unit controlling the ignition system, so that the control unit will initiate the generation of a plurality of sparks, instead of a single spark, at ignition time points.

Abstract: Disclosed is a method and system for controlling, in a multi-cylinder four-stroke internal combustion engine, the spark ignition in at least two cylinders, the pistons of which simultaneously assume a top dead center position. The method and system achieve a more reliable start with low supply voltage. For this purpose, the charging and discharging of an ignition capacitor is controlled by a control unit in such a way that, when the pistons in a pair of cylinders pass through the same crankshaft angle range close to the top dead center position, ignition is generated in first one and then the other of the pair of cylinders. Between the times for generating the ignition, the ignition capacitor is charged as a function of supply voltage so that a full charge is utilized for generating the ignition sparks in the cylinders.

Abstract: The invention relates to a method for detecting ion current in an ignition circuit included in the ignition system of an internal combustion engine, where a measuring voltage is applied to the ignition circuit and a measuring device is utilized for detecting ion current possibly present in the ignition circuit. In known solutions of this kind, it has been necessary to use comparatively expensive electronic components, usually not manufactured as standard, to protect the outside voltage source from high voltages occurring in the ignition circuit. The problems are aggravated when the prior art is applied to capacitive ignition systems.