United States Patent (19) (11) 4,364,353 Fiala 45) Dec. 21, 1982 (54) ANTI-KNOCKING APPARATUS FOR AN 4,153,020 5/1979 King et al. .......................... 123/425 NTERNAL COMBUSTON ENGINE FOREIGN PATENT DOCUMENTS 75) Inventor: Ernst Fiala, Wolfsburg, Fed. Rep. of 2274796 1/1976 France. Germany 2337261 7/1977 France . 73) Assignee: Volkswagenwerk Aktiengesellschaft, Wolfsburg, Fed. Rep. of Germany OTHER PUBLICATIONS SAE-Paper No. 7901 73, "Energy Conservation with 21 Appl. No.: 219,352 Increased Compression Ratio and Electronic Knock 22 Filed: Dec. 22, 1980 Control', by Currie, Grossman and Gumbleton, 1979. (30) Foreign Application Priority Data Primary Examiner-Charles J. Myhre Assistant Examiner-Andrew M. Dolinar Dec. 20, 1979 DE Fed. Rep. of Germany ....... 2951321 Attorney, Agent, or Firm-Spencer & Kaye (5) Int. Cl............................ F02P 5/14; F02D 9/00 52 U.S.C. ..................................... 123/425; 123/435 57 ABSTRACT 58) Field of Search ............... 123/425, 419, 435, 436, For reducing knocking in an externally ignited, mix 123/198 A ture-compressing internal combustion engine, the mo ment of ignition is delayed up to a predetermined maxi (56) References Cited mum as a function of signals emitted by a knocking U.S. PATENT DOCUMENTS sensor. Thereafter, if engine knocking continues, the 2,401,563 6/1946 Hersey ................................ 123/425 throttle valve is moved in the closing sense. 2,595,524 5/1952 Henneman et al.................. 123/435 4,002,155 1/1977 Harned et al. ...................... 123/425 1 Claim, 2 Drawing Figures DEAD PONT 31 37 NDICATOR 32 23 25 26 SERVO DISTR MECHANISM KNOCKING ME SIGNAL AMPL SELECTOR BUTOR SENSOR WINDOW.COMPARATOR ER TCH SERVO THROTTLE 20 22 MECHANISM WAWE EVEL 24 ACCOMO CONTROL ;ARACTERSTC ACCELERATOR DATION LOGIC MEMORY PEDAL ENGINE THROTTLE SPEED ANGLE SENSOR NDICATOR 30 IGNITION ANGLE NDCATOR 29 U.S. Patent Dec. 21, 1982 Sheet 1 of 2 4,364,353 U.S. Patent Dec. 21, 1982 Sheet 2 of 2 4,364,353 OA}}ES RENFR??? OLISIHBLOWHWHOT” EnTVAI TOEKERT TOHINOO 5,55T 08 OZ 4,364,353 1. 2 ANTI-KNOCKING APPARATUS FOR AN DESCRIPTION OF THE PREFERRED INTERNAL COMBUSTION ENGINE EMBODIMENT Turning to FIG. 1 there is schematically shown a 5 cylinder 1 of a multicylinder, externally ignited, mix BACKGROUND OF THE INVENTION ture-compressing internal combustion engine. The cyl This invention relates to an apparatus for operating inder 1 accommodates a reciprocating piston 2, the top an externally ignited, mixture-compressing internal face of which, together with a cylinder head 3, bounds combustion engine wherein the ignition is delayed as a a combustion chamber 4 of variable volume. Into the function of signals emitted by a knocking sensor. 10 combustion chamber 4 merge an intake conduit 5 con It is known to decrease the tendency of knocking in trolled by an intake valve 6 as well as an exhaust con an externally ignited, mixture-compressing internal duit 7 controlled by an exhaust valve 8. A spark plug 9 combustion engine by altering the moment of ignition. projects into the combustion chamber 4 for igniting the In this manner, the mixture compression in the internal combustible mixture enclosed in the combustion cham combustion engine can be increased particularly in 15 ber when the piston 2 is in the zone of the upper dead order to achieve a better degree of efficiency in the center at the end of the compression stroke. partial load range and to thus achieve a better fuel con In the intake conduit 5there is arranged a carburetor sumption. The tendency of knocking which appears 10 which admixes fuel to the intake air in a quantity during full load and high rpm's is reduced by a corre adapted to the momentary operational condition of the sponding shift in the moment of ignition. Since knock 20 internal combustion engine. The carburetor 10 is ar ing appears dependent upon the available fuel under ranged upstream of a branch-off (not shown) leading to different values of final mixture compression, it is con the other engine cylinders. Downstream of the carbure ceivable that a circumstance sets in when despite a tor 10, as viewed in the direction of the mixture flow substantial shift of the ignition angle in the delaying towards the combustion chamber 4, there is arranged a sense, knocking is still not eliminated. Such an occur 25 throttle valve (butterfly valve) 11 which is operated by rence can lead to a damage to the internal combustion an accelerator pedal (not shown) for controlling at will engine. the output of the internal combustion engine. A knocking sensor 12 is arranged at the cylinder 1 SUMMARY OF THE INVENTION . and responds when knocking in the cylinder occurs, by 30 emitting signals to a control device 13 which, as a func It is an object of the invention to provide an im tion of the signals received from the knocking sensor 12, proved apparatus with the aid of which the ignition actuates a device. 14 for shifting the ignition angle of the angle shift in the delaying sense is limited, yet knocking spark plugs 9 as well as a device 15 for changing (de is effectively eliminated. " creasing) the angle of the throttle valve 11. Thus, when This object and others to become apparent as the 35 knocking occurs in a combustion chamber of the inter specification progresses, are accomplished by the inven nal combustion engine, first the ignition angle of the tion, according to which, briefly stated, the shift of the spark plugs is shifted in the delaying sense in a manner ignition angle in the delaying sense is effected only up to known by itself. This delaying shift of the ignition an a predetermined maximum value and, in case knocking gle, however, continues only up to a predetermined continues, the throttle valve angle is progressively re maximum value. If, upon reaching such value, engine duced, until engine knocking is suppressed. knocking persists and thus the knocking sensor 12 con By reducing the throttle valve angle according to the tinues to respond, the device 15 is actuated for progres invention, it is ensured that in case the ignition angle sively reducing the throttle valve angle, that is, for shift in the delaying sense has still not resulted in an progressively increasing the throttle effect. Thus, in elimination of knocking, a further knocking is reliably 45 order to avoid damage to the internal combustion en eliminated by reducing the engine output. In this man gine in case of continuing knocking after a predeter ner, internal combustion engines can be satisfactorily mined ignition delay has been achieved, the output of operated - by foregoing a maximum power output, to be the engine is progressively reduced and thus, by reduc sure - with inferior fuel even when the final mixture ing the charge, the mixture compression drops and compression is such that it would otherwise cause 50 engine knocking is suppressed. knocking. Further, by limiting the shift of the ignition angle, an The apparatus according to the invention comprises a excessively high exhaust gas temperature is avoided knocking sensor, an ignition angle shifting device and a which could cause damage to the exhaust pipe and/or throttle valve adjusting device, both responsive to sig to the exhaust gas catalysts connected with the exhaust 55 pipe. The throttle valve adjusting system, however, has nals of the knocking sensor. When engine knocking to be so structured - for example, by including spring occurs, first the ignition angle shifting device is actuated elements - that despite a fully depressed accelerator and delays ignition up to a predetermined maximum. If pedal, a turning of the throttle valve by the device 15 in knocking persists, the throttle valve adjusting device the closing sense is nevertheless feasible. responds to the knocking sensor and progressively re 60 The above-described anti-knocking control will now duces the throttle valve angle. be set forth in more detail with reference to FIG. 2. BRIEF DESCRIPTION OF THE DRAWING In FIG. 2, there is shown a knocking sensor 20 for emitting signals when knocking in the cylinders of the FIG. 1 is a schematic and diagrammatic elevational engine occurs. In order to use only one knocking sensor view of a preferred embodiment of the invention; and 65 for all cylinders of the engine and to insure that the FIG. 2 is a block diagram illustrating the basic ar knocking vibration will be transmitted as equally as rangement of the anti-knocking apparatus according to possible from all cylinders, the location of the sensor the present invention. has to be carefully selected. A preferred point for 4,364,353 3 4. mounting the knocking sensor may be the intake mani 29 with the predetermined maximum value delivered by fold of the engine. m the characteristic value memory 36 and changes over A knocking sensor formed by a magnetostrictive the selector switch 26 to the second position if the pre accelerometer which can be used in the knocking appa determined maximum value is reached. ratus according to the invention is shown and described The servomechanisms 31 and 33 for shifting the igni in the SAE-Paper No. 79 01 73 entitled "Energy Con tion distributor 32 and the throttle valve 34, respec servation with Increased Compression Ratio and Elec tively, are well known in the art and can be operated for tronic Knock Control' by James H. Currie, David S. example by suction pressure delivered from the intake Grossman and James J. Gumbleton. conduit of the engine upstream the throttle valve. It is The knocking sensor 20 of FIG. 2 is connected to a 10 feasible, however, to operate the servomechanism by filter 21 which cuts off the frequency ranges which are hydraulic or electric means.