Abstract: An engine timing instrument as disclosed which is particularly designed for use with diesel engines and which responds to the actual time of firing within a cylinder. A strobe may be flashed at the crankshaft angle at which firing occurs and the crankshaft of the strobe flash may be advanced with respect to the firing angle until the strobe flash occurs at a top dead center position. The angle of advance of the strobe flash is measured to then indicate the angle of firing relative to the top dead center position. Important features relates to the use of a piezoelectric transducer placed in a glow plug hole to measure pressure, the transducer being connected to circuitry which provides both a firing pulse and a reference pulse. The reference pulse occurs close to and not later than the top dead center position and is used to measure the time of a subsequent firing pulse.

Abstract: A stroboscopic timing system for diesel engines of the type having apertures in each cylinder for normally accepting glow plugs. A signal that varies in accordance with pressure changes within the cylinder is generated by a piezoelectric transducer mateable with a glow plug aperture, and the transducer signal is processed by filtering and other discriminating circuitry to provide a timing pulse that occurs upon the initiation of combustion within the cylinder. A conditioning circuit shapes this pulse into suitable form for triggering a high intensity stroboscopic light for illuminating timing marks on the engine drivetrain.

Abstract: A transducer device is provided which is arranged to be mounted on flow path-defining structure of a fuel injection system, preferably on the outside of a delivery valve housing including a chamber in which a surge of pressure is built up during operation of the injection pump to cause a transducer of the device to develop a high amplitude and high rate of change electrical signal. The device is readily clamped in place and is light in weight with a center of gravity close to the axis of the chamber, the effect of engine vibrations being minimized. The signal from the device and a signal developed at a predetermined rotational position of the engine crankshaft are applied to an instrument which indicates the relative timing of the signals and the RPM.

Abstract: A system and method for monitoring the performance and condition of various cylinder components of internal combustion engines through the provision of a transducer for detecting the time-rate-of-change of pressure within the cylinder during normal operation of the engine and a circuit for processing and quantizing the transducer signal to develop a numerical indication of pressure changes within the cylinders. The system also includes a tachometer circuit and display apparatus as well as an optional memory and processor to facilitate a comparative analysis of the various cylinders at varying speeds.

Abstract: Method and apparatus for timing combustion events in the combustion chamber of an internal combustion engine wherein a piezoelectric transducer is utilized to develop a signal corresponding to the first derivative of pressure within the cylinder being monitored. A signal processing circuit detects that change in polarity of the first derivative signal which occurs at the transition between compression and expansion of cylinder volume during the combustion cycle of the piston. Circuitry is provided for effectively disregarding all other polarity changes or "zero crossings" of the transducer output signal which are not related to the achievement of the top dead center position by the piston within the cylinder. This directly derived indication of a transition from compression to expansion in the combustion chamber is combined with other timing signals for the monitoring or controlling of injection or ignition timing for the engine.

Abstract: Disclosed is a transducer assembly and diagnostic apparatus for processing an electrical signal which varies with the pressure changes occurring within an engine cylinder. The transducer assembly consists of a U-shaped structure integrally formed in a sandwich arrangement and encompassing a pressure-responsive crystalline element. The assembly is sized such that it substantially encompasses the shank of a spark or glow plug of the engine such that axial forces from within the cylinder excite the transducer through the plug to produce a signal which is processed in an electrical circuit to provide timing or other diagnostic information.

Abstract: A transducer and associated diagnostic system for fuel injected diesel engines of the type having glow plugs to provide supplementary ignition during starting and warm-up periods. A piezoelectric transducer unit is adapted to screw into the receptacle normally provided in each cylinder for a glow plug. The unit includes a piezoelectric element which is held under tension by a conductive rubber plug which coacts with a coaxial connector in transmitting the pressure indicative output signal. The transducer develops an electrical signal which varies in accordance with the pressure-time characteristic of the cylinder combustion chamber, the electrical signal representing performance of each cylinder being processed individually to provide timing and other valuable information or being combined with electrical signals developed for other cylinders of the engine in a comparative diagnostic system.

Abstract: An electronic timing system for fuel-injected engines is disclosed in which a direct readout is provided for measuring the time relationship between fuel injection and the achievement of the top dead center (TDC) condition in a preselected cylinder of a diesel engine. A piezoelectric transducer coupled to the fuel-injection system provides a pulse upon the injection of fuel into a feed line for the selected cylinder. This pulse is detected in a noise blocking, variable threshold, amplifying circuit and initiates a timing pulse, the width of which constitutes a delay period after which a strobe light is activated for observation of timing marks on the engine. By adjusting the timing pulse width or delay of the strobe light such that illumination occurs at the time the piston reaches top dead center within the cylinder, as indicated by the timing marks on the dynamic damper, the width of the delay or timing pulse can be taken as representative of timing advance.

Abstract: Engine monitoring apparatus is disclosed in which the cylinder pressure changes in a fuel injected engine are monitored through the use of a transducer device which produces an electrical signal responsive to pressures exerted on an injector nozzle from within the cylinder. The transducer is mounted to the nozzle holding brackets or fasteners which act to maintain pressure tending to seat the nozzle against an inlet port in the cylinder and, as such, is responsive to axial pressures exerted on the nozzle assembly from within the cylinder. Methods and apparatus for mounting the transducer device to the holding brackets of various types of nozzle assemblies are disclosed along with read-out devices including a tachometer circuit for utilizing the transducer output signal for performance monitoring and diagnostic applications.