US4199812A — Apparatus for determining the duration of fuel in…

Claim 1

Independent Claim 282 words

In an apparatus for determining the duration of the injection-control commands to be applied to the injection valves associated with an internal combustion engine, the duration of injection depending at least on engine rpm, temperature and airflow in the suction tube, including an air-quantity meter generating an air-quantity proportional potential, a temperature sensor in the vicinity of the internal combustion engine, a tachometer, and a computer circuit computing the duration of the injection pulses from the data provided, the improvement comprising: a first counter fed by a counting frequency which is proportional to the amount of air taken in by the engine within a predetermined angle of rotation of the crankshaft. an analog-to-frequency converter connected to the air-quantity meter and to the first counter for processing the output potential of said air-quantity meter, means for converting engine temperature into a proportional frequency, a multiplier circuit connected with the last-named means, an addressable read-only memory connected with the multiplier circuit, the stored data values in said memory being issued as a function of further operational parameters and being multiplicable by said temperature-proportional frequency in said multiplier circuit, means for generating at least one other frequency derived from at least one other operational parameter; means for receiving and summing the output frequency of the multiplier circuit and said at least one other frequency in order to generate a total correction frequency, and a second counter which takes over the contents of said first counter for count-out at said total correction frequency; whereby the duration from the time of transfer to the time of a predetermined counter content may be used as a measure for the duration of the fuel injection time per piston stroke.

Claim 2

Dependent Claim 282 words

In an apparatus for determining the duration of the injection-control commands to be applied to the injection valves associated with an internal combustion engine, the duration of injection depending at least on engine rpm, temperature and airflow in the suction tube, including an air-quantity meter generating an air-quantity proportional potential, a temperature sensor in the vicinity of the internal combustion engine, a tachometer, and a computer circuit computing the duration of the injection pulses from the data provided, the improvement comprising: a first counter fed by a counting frequency which is proportional to the amount of air taken in by the engine within a predetermined angle of rotation of the crankshaft. an analog-to-frequency converter connected to the air-quantity meter and to the first counter for processing the output potential of said air-quantity meter, means for converting engine temperature into a proportional frequency, a multiplier circuit connected with the last-named means, an addressable read-only memory connected with the multiplier circuit, the stored data values in said memory being issued as a function of further operational parameters and being multiplicable by said temperature-proportional frequency in said multiplier circuit, means for generating at least one other frequency derived from at least one other operational parameter; means for receiving and summing the output frequency of the multiplier circuit and said at least one other frequency in order to generate a total correction frequency, and a second counter which takes over the contents of said first counter for count-out at said total correction frequency; whereby the duration from the time of transfer to the time of a predetermined counter content may be used as a measure for the duration of the fuel injection time per piston stroke.

Claim 3

Dependent Claim 99 words

An apparatus as defined in claim 1, wherein the analog-to-frequency converter includes a binary up-down counter clocked by a counting frequency, a frequency multiplier connected to the up-down counter for converting the contents of said up-down counter, which are proportional to the air-quantity, into an air-quantity dependent frequency, and a comparator for generating the air-quantity dependent frequency, one input of said comparator receiving said air-quantity proportional potential and the other input receiving a feedback analog value related to said generated air-quantity frequency, and wherein the output signal of said comparator indicates the counting direction of the binary up-down counter.

Claim 4

Dependent Claim 54 words

An apparatus as defined in claim 2, wherein said frequency multiplier is a DDA series multiplier so connected that a relatively high input frequency applied to it may be divided into a number of non-coincident partial frequencies which may be selected depending on the associated position of the word formed in the up-down counter.

Claim 5

Dependent Claim 45 words

An apparatus as defined by claim 2, wherein said frequency multiplier is a parallel DDA multiplier in which the binary word formed in said up-down counter is added to itself at a predetermined frequency, and the number of overflows is exploited as said air-quantity frequency.

Claim 6

Dependent Claim 71 words

An apparatus as defined in claim 2, wherein the analog-to-frequency converter further includes a shaping circuit for receiving said air-quantity frequency generated at the output of said frequency multiplier and for performing a pulse-shaping compensation in step with fluctuations of the on-board power supply potential, wherein the output potential of said shaping circuit is fed to a subsequent integrating RC circuit which is connected to the other input of said comparator.

Claim 7

Dependent Claim 131 words

An apparatus as defined in claim 1, wherein said read-only memory receives a first partial address from an address counter depending on the operational state of the internal combustion engine, the parallel outputs of said read-only memory being connected to a DDA multiplier circuit for the conversion of the interrogated memory datum into a frequency, and wherein the counting frequency fed to the DDA multiplier embodied as a series multiplier is a frequency proportional to the engine temperature, and wherein a second partial address for said read-only memory is derived in parallel from the MSB outputs of said series multiplier for the purpose of interpolation, the output frequency from said series multiplier being fed to a subsequent binary up-down counter for the purpose of summing interpolations carried out in chronological sequence.

Claim 8

Dependent Claim 36 words

An apparatus as defined in claim 6, further comprising an initial value memory to which said counter which receives the output frequency from said series multiplier is connected for the purpose of transferring an initial value.

Claim 9

Dependent Claim 109 words

An apparatus as defined by claim 6, further comprising a control circuit for analyzing the particular operational states of the internal combustion engine, for controlling said address counter and for the cyclical formation of the partial addresses corresponding to the particular operational states, said control circuit causing a transfer of the counter contents of said up-down counter into a correction memory in cyclical sequence and when further operational states occur, said control circuit further causing the renewed setting of an initial value in said up-down counter, wherein the contents of said correction memory may be converted by means of an associated series multiplier into a first partial correction frequency.

Claim 10

Dependent Claim 108 words

An apparatus as defined in claim 8, further comprising means for generating an analog signal as a function of at least one other operational state, preferably the fuel-air ratio sensed by an oxygen probe in the engine exhaust, said analog signal being fed via a threshold circuit to a binary up-down counter for the determination of the counting direction thereof, and further comprising a series multiplier associated with said binary counter for the conversion of the continuously integrated potential into a further partial correction frequency, which together with said first partial correction frequency forms the total correction frequency at a summing point for counting out said second counter.

Claim 11

Dependent Claim 50 words

An apparatus as defined by claim 1, further comprising an intermediate memory for receiving the contents of said first counter counting the air-quantity frequency during a predetermined angle of the crankshaft rotation, the contents of said intermediate memory being fed to said second counter counting at the total correction frequency.

Claim 12

Dependent Claim 55 words

An apparatus as defined in claim 10, wherein said first counter and said second counter are designed as stochastic counters and comprise a number of sequentially connected flip-flop circuits the outputs of which are fed back over junction circuits such that one may obtain a defined output sequence of counter counts in a statistical distribution.

Claim 13

Dependent Claim 79 words

An apparatus as defined in claim 10, characterized in that upon transfer of the uncorrected value from said intermediate memory into said second counter an output flip-flop is set into one of its states, and that upon reaching a predetermined count in said second counter, said output flip-flop is returned by a null-sensing circuit into its initial state in such manner that the dwell time of said output flip-flop corresponds to the duration of fuel injection to said engine.

Claim 14

Dependent Claim 91 words

An apparatus as defined by claim 1 further comprising a control circuit and an associated address counter so connected that operational states simultaneously present will be converted in time sequence by interpolation into an output frequency of a series multiplier at said read-only memory and are stored as a sum in a subsequent binary up-down counter, wherein, when further operational states occur, correction values are obtained in cyclical sequence by erasing the content of said binary up-down counter and if appropriate by setting a new initial value from an initial-value memory.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1983-04-22	1983-10-22	1984-04-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1987-04-22	1987-10-22	1988-04-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1991-04-22	1991-10-22	1992-04-22	$7700.00	Window Closed / Lapsed

Apparatus for determining the duration of fuel injection control pulses

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