Apparatus for the determination of internal combustion engine compression pressure

Abstract

The compression pressure of each of the cylinders in an internal combustion engine is represented by a voltage obtained at a tap on the ground cable of the engine and stored in a respective accumulator by control outputs from a shift register which successively activates each of the accumulators to receive the data associated with the starting current of each cylinder. The input to the shift register is fed from the output of a NAND gate having inputs representing the impulses from all the cylinders, the impulses from a cylinder selected as a synchronizing or coordinating cylinder, a main control signal, and a signal from the output of the last accumulator.

What is claimed is:  .[.1. Apparatus for the determination of the compression pressure in the cylinders of an internal combustion engine equipped with a starter and voltage source, said apparatus having means for generating electrical signals representative of the starting current of said engine, and means for generating coordination signals from at least one of said cylinders, the improvement comprising: 
     
        connection to the first cylinder of said engine..]..[. 4. Apparatus as in claim 1 wherein said coordination signals are generated by an inductive or capacitative pick-up from the ignition cable of at least one of said cylinders..]. .[.5. Apparatus as in claim 1 wherein said means for gating further includes a NAND gate for generating control signals for controlling the transfer of said electrical signals to said means for storing, and said means for delaying is responsive to at least one of said coordination signals to provide an input to said NAND gate..]. .[.6. Apparatus as in claim 5 wherein said means for delaying includes a holding circuit triggered by said coordination signals for providing an input signal to said second input..]. .[.7. Apparatus as in claim 1 wherein said means for delaying provides a delay substantially equal to a time period required for the stabilization of the compression pressures of said cylinders..]. .[.8. Apparatus as in claim 1 wherein said means for storing includes a storage device for storing the electrical signal for each cylinder of said engine, said electrical signals are fed to said storage devices, each of said storage devices including a control input, said means for gating further including a shift register responsive to said means for gating for generating a control signal for each of said storage devices during one complete starting cycle of said cylinders, whereby an electrical signal representative of the starting current of each of said cylinders is successively fed to a respective one of each of said storage devices..]. .[.9. Apparatus as in claim 8 further comprising an electrical connection between that storage device last controlled in said one complete starting cycle and said means for gating, and the control signal to said last controlled storage device generates therefrom a feedback signal via said electrical connection to block said means for gating..]. .[.10. Apparatus as in claim 1 further comprising first and second low pass filters for respectively filtering said electrical signals and said coordination signals..]. .Iadd. 11. Apparatus for the determination of cylinder compression pressure of an internal combustion engine having a starter, by storage of signals representative of starter current and generating coordination signals from the ignition impulses of the engine, the apparatus comprising, a gating circuit having a first input for receiving signals corresponding to the ignition impulses of all cylinders of the engine, and a second input for receiving signals initiated by the ignition impulses from a selected engine cylinder; means for storing said signals representative of starter current; and   said gating circuit passing to said means for storing said signals received by said first input only during presence of said signals received by said second input for actuating said means for storing. .Iaddend. .Iadd. 12. Apparatus as in claim 11 wherein the signal representative of the starter current is the voltage drop in the ground line of the engine voltage source. .Iaddend..Iadd. 13. Apparatus as in claim 11 wherein said selected cylinder is the first cylinder of the engine. .Iaddend..Iadd. 14. Apparatus as in claim 11 wherein signals representative of the ignition impulses are obtained from the ignition cable associated with the engine cylinders. .Iaddend. .Iadd. 15. Apparatus as in claim 11 wherein said gate circuit includes a NAND gate connected to the input for receiving ignition impulses from said selected engine cylinder for providing control signals to said means for storing. .Iaddend..Iadd. 16. Apparatus as in claim 15 further comprising means for shaping the signals representative of the ignition impulses of said selected engine cylinder. .Iaddend..Iadd. 17. Apparatus as in claim 11 further comprising means for delaying the storage of said signals for a time period required for stabilization of the compression pressures of said cylinders. .Iaddend..Iadd. 18. Apparatus as in claim 11 wherein said means for storing includes storage circuits and further comprising a shift register connected to the output of said gating circuit and providing outputs to each of said storage circuits. .Iaddend..Iadd. 19. Apparatus as in claim 18 wherein the storage circuit last triggered in an engine cycle is connected to an input of said gating circuit for blocking said gating circuit. .Iaddend..Iadd. 20. Apparatus as in claim 11 further comprising a low pass filter connected in each of the inputs of said gating circuit. .Iaddend.