Abstract: A system and method for air compressor control wherein the air compressor is loaded only when engine activities require it to be loaded or when free engine power is available to operate the compressor. An air compressor system is an engine-driven, piston-type compressor which operates in a loaded and an unloaded mode and provides air to a vehicle's air powered devices, such as service brakes, air suspension, windshield wipers, etc. The operating mode of the compressor is controlled by a pressure activated air governor which applies an air signal when pressure in a reservoir reaches a set level that activates a cap valve on an unloader stopping the air compressor. When the air pressure in the reservoir drops below a lower set pressure or when energy is "free," such as during downhill operations, the air governor exhausts the air signal allowing the air compressor to resume operation.

Abstract: A controlled energy ignition system for an internal combustion engine includes an ignition coil having a primary coil and a secondary coil coupled to first and second electrodes of an ignition plug defining a spark gap therebetween, wherein the primary coil is responsive to activation of a control signal to produce a spark voltage across the secondary coil and across the spark gap. The secondary coil is responsive to the spark voltage to produce a discharge current across the spark gap of the ignition plug. In accordance with one aspect of the invention, means are provided to draw discharge current away from the ignition plug to thereby limit the discharge current to below a threshold current value within some predefined time period after activation of the control signal.

Abstract: A combustion seal for sealing high pressure combustion gas within at least one cylinder of an internal combustion engine including a cylinder block, a cylinder head having a groove formed in its bottom face, a cylinder liner having a complementary groove formed in its top face, and a O-ring formed from a ductile material and positioned between and contacting each edge of the groove formed in the cylinder head and the complementary groove formed in the cylinder liner, wherein the O-ring is compressed when the cylinder head is secured on the cylinder such that the O-ring has multiple radial restraint points of contact with the edges. When securing the cylinder head onto the cylinder block, the O-ring is positioned between the grooves in the cylinder head and cylinder liner before a compressive force is applied.

Abstract: An improved unit fuel injector is provided which effectively and precisely controls the timing of fuel injection by avoiding outside influences acting on a timing plunger. The unit fuel injector includes a timing plunger positioned between upper and lower plungers, a timing chamber positioned between the timing plunger and upper plunger and a spring chamber positioned between the timing plunger and a metering chamber for containing one or more springs for biasing the plungers. A spring chamber drain valve device is provided for directing fuel in the spring chamber to a low pressure drain while isolating the spring chamber from the low pressure drain system thereby preventing pressure variations in the drain system from entering the spring chamber and acting on the timing plunger. In addition, a scavenge circuit is provided to direct a scavenging flow of fuel and combustion gas from the injector directly to the low pressure drain without communication with the spring chamber.

Abstract: A swirl tip injector nozzle housing is provided for a fuel injector which includes a fuel atomization enhancing feature for creating effective fuel atomization and breakup during discharge from the injector. The fuel atomization enhancing feature includes a plurality of curvilinear spray holes having an angle of curvature equal to approximately 90 degrees. Fuel flowing from the inlet of each spray hole to the outlet is induced, by the 90 degree angle of curvature, to flow through a tangential flow path or swirl within the spray hole causing rapid spreading and breakup of the fuel jet spray upon exiting the outlet of the spray hole. The fuel atomization enhancing feature may also include positioning each spray hole so as to extend orthogonally from the interior surface of the fuel cavity to create optimal entry of the fuel into the tangential flow path.

Abstract: The present invention relates to a method and apparatus for control of current rise time during multiple fuel injection events. The invention utilizes a single boost voltage supply circuit, in which the boost capacitor is designed to store slightly more than twice the total energy required to pull-in a single fuel injector solenoid during the prescribed time. A reference waveform simulating the desired current rise time is compared to the actual boost voltage produced by the circuit. The boost voltage is modulated (switched on and off) in order to maintain the boost voltage within a predetermined window around the reference waveform. This modulation will compensate for any droop in boost voltage at the time of actuation, and will also compensate for two solenoids being actuated at the exact same time.

Abstract: A method for accurately and economically shaping a zirconia workpiece with a relatively inexpensive silicon carbide grinding wheel is provided. The grinding wheel used in the method preferably utilizes 220 mesh silicon carbide particles bound in a low porosity vitreous matrix. The grinding wheel is then rotated at a sufficient speed to implement a grinding operation, and is engaged against the zirconia workpiece at a diametral feed rate of at least 0.04 mm/sec. The method advantageously removes material from the zirconia workpiece at a high rate of speed with minimal wheel wear, and results in accurate cuts and smooth surface finishes, and also eliminates the need for dressing the wheel prior to the grinding operation.

Abstract: A unit fuel injector is provided which includes a threadless injector body attaching device for attaching an upper body section of the fuel injector to a lower body section while avoiding imparting a transverse load to the upper body section thereby minimizing bore distortion, plunger wear and the likelihood of injector failure. The threadless injector body attaching device includes a groove formed in the lower end of the upper body section and one or more apertures extending through the lower body section for positioning adjacent the groove. Also, one or more pins are provided for insertion into a respective aperture and connection to the lower body section. The groove and opposing aperture or apertures are sized to create a slip fit to avoid a contact force between the pin or pins and the upper body section.

Abstract: Manufacturing/design imperfections and component failures in the fuel system/engine can lead to non-uniform torque production among the cylinders. Non-uniform cylinder torques can be observed as small engine speed fluctuations about the average engine speed at any given operating point. Severe imbalance conditions can be heard, felt, and seen by human operators. The present invention uses the fluctuations in engine speed to detect an unbalanced engine and attempts to correct the unbalance by applying trims to the fueling commands for each individual cylinder. The present invention is based on the calculation of a 6-point Fourier Transform (FFT) of engine speed data over one complete engine cycle. This FFT is calculated continuously to provide imbalance detection. An unbalanced engine results in non-zero magnitudes of the FFT components that correspond to the 0.5, 1.0, and 1.5 engine orders.

Abstract: A vehicle/engine acceleration rate management system includes means for determining vehicle acceleration rate and a control computer providing a fueling signal to an internal combustion engine fueling system. The control computer is responsive to a gear ratio signal indicative of one of a plurality of selectable transmission gear ratios currently engaged with the engine and a vehicle acceleration rate signal to control the vehicle acceleration rate by limiting the fueling signal whenever the vehicle acceleration rate signal exceeds a vehicle acceleration limit function. In one embodiment, such vehicle acceleration rate limiting is performed only for vehicle speeds above a threshold vehicle speed, and an identical engine acceleration rate limiting procedure is performed at vehicle speeds below the threshold vehicle speed. In either case, such acceleration rate limiting is preferably only performed under manual control of engine fueling via an accelerator pedal or the like.

Abstract: An engine control system includes a speed sensor apparatus for providing signals to an engine control module (ECM) indicative of the speed and timing of an internal combustion engine. The apparatus includes a primary and a secondary Hall device affixed to one pole of a dipole magnet. Independent flexible circuits connect each of the Hall devices to an output connector adapted to receive a cable connected to the ECM. The magnet, primary and secondary sensors and primary and secondary flexible circuits are potted and encased within a sensor housing that is configured for sealed mounting to a housing surrounding the timing wheel of the engine. The outputs from the two sensors are independent of each other and are simultaneously provided to the ECM. The ECM includes means for providing the output from the primary sensor to engine control routines utilizing speed and timing information while the primary sensor is operational.

Abstract: A back-up battery system is provided for use with a real-time clock of an on-board device controller. In its normal operation, the real-time clock (RTC) is powered by a primary power source, such as a vehicle battery. When the primary source is interrupted, the back-up battery system is invoked to provide back-up power to the RTC. The system includes a low voltage dry cell battery mounted within a fuse component configured for electrical engagement within the vehicle fuse block. In one embodiment, a relay is interposed between the fuse component and the RTC to make and break the back-up power circuit in response to the state of the primary power source. In another embodiment, the battery within the fuse component is replaceable, with the fuse component including a base and a removable cap. In still another embodiment, the battery within the fuse component is a rechargeable battery, and the back-up power system includes a recharging circuit operable with the primary power source.

Abstract: An internal combustion engine with an embedded control system is disclosed which includes a programmable controller operatively coupled to a nonvolatile memory and a volatile memory. The nonvolatile memory is loaded with programming instructions for the controller. In one embodiment, a portion of the programming instructions are provided in an unexecutable compressed format which are then selectively decompressed into an executable format by an executable routine loaded in another portion of the nonvolatile memory. In another aspect, a first loading program is executed by the controller to load data from external support equipment. This data includes a second loading routine. The downloaded data also includes a code substitution program which is executed to replace the first loading routine with the second loading routine.

Abstract: A system for controlling automatic transmission downshift points includes a control computer for electronically controlling an internal combustion engine and a transmission having at least one automatically selectable gear. The control computer is responsive to at least a throttle signal, provided by either a manually actuatable accelerator pedal or a cruise control system, to compute an engine load value, and is further responsive to either an engine speed signal or a vehicle speed signal to compute a deceleration value. The control computer is operable to compute a downshift engine RPM value based on the deceleration value and either the throttle signal or the engine load value, wherein the downshift engine RPM value is lower than a default downshift engine RPM if the deceleration value indicates a relatively slow deceleration rate and the throttle signal or the engine load value indicates high throttle or engine load.

Abstract: A system and method for the diagnosis and prognosis of cylinder power imbalance in an internal combustion engine utilizes cylinder firing times to determine a differential value indicative of the power imbalance. This differential value identifies a cylinder power imbalance condition and can be used in a one dimensional or a two dimensional analysis to predict future engine performance. In one embodiment, a trend parameter is calculated from the differential values over several test sequences at periodic mileage of the vehicle. The rate and magnitude of change or deterioration of the engine performance is indicated by the trend parameter. In another embodiment, a two dimensional trend array is evaluated using singular value decomposition to arrive at an eigenvalue transformation matrix used to obtain two trend variables related to the two principal eigenvalues at a particular engine operating hour/mileage.

Abstract: An apparatus for diagnosing and controlling an ignition system of an internal combustion engine includes an ignition coil controllable by an ignition control circuit, a spark voltage sensor electrically connected to the high tension side of the ignition coil secondary and an ion voltage sensor electrically connected to the low tension side of the ignition coil secondary. A computer processes the spark voltage signal by comparing the signal to a number of predefined spark voltage waveforms in memory. If the spark voltage signal matches any of the spark voltage waveforms in memory that correspond to a predefined ignition system failure mode, a corresponding error code is stored in memory. The computer is further operable to process a voltage peak of the spark voltage, wherein the voltage peak corresponds to the breakdown voltage in the spark gap of a spark plug connected to the secondary coil.

Abstract: A system and method for measuring individual cylinder power contribution by cutting out individual cylinders of a multi-cylinder engine and performing a snap-throttle test on the engine. Engine speed versus time data is collected and stored during each snap-throttle test. This data is then used to calculate the power contribution provided by each cylinder using various methods, such as a least squares analysis of the speed data or by an analysis of the kinetic energy of the test engine.

Abstract: An engine control system for a vehicle engine includes an engine control module (ECM) that enters a modified sleep mode when the vehicle key switch is turned to the "off" position. In the modified sleep mode, all non-essential operating tasks normally executed by the ECM are disabled to place the ECM in a mode of reduced power consumption. In addition, various communications interrupts are disabled, except for interrupts associated with at least one external data transmission device. During the modified sleep mode, priority for communications with the external device are highest to permit external communication to and from the ECM using the external device. In this modified sleep mode, the vehicle operator or engine technician can download or upload data to and from the ECM memory. The ECM includes a sleep mode task module that is maintained during the modified sleep mode. The sleep mode task module controls a sleep mode termination timer (SMT timer) that counts the time the ECM is in the modified sleep mode.

Abstract: In an internal combustion engine, a barring adapter member is mounted on an auxiliary engine component, such as an air compressor shaft which is geared to the engine crankshaft. The barring adapter member is configured to receive a barring tool, permitting manual rotation of the air compressor shaft for desirably positioning engine crankshaft-driven components during engine repair or adjustment. In an arrangement according to the invention, the air compressor gear is enclosed by a gear casing, but the adapter is accessible through an aperture closeable by a removable cap. The barring adapter member facilitates barring the engine from a convenient position and is particularly advantageous in an engine designed to eliminate most externally-exposed rotational shaft seals and associated external pulleys conventionally used as barring locations.

Abstract: A fuel cooler and coolant filter assembly for the filtering of coolant and the cooling of a fuel flow for use in connection with a cylinder head of a vehicle engine includes three primary components which are assembled to one another in a stacked configuration and which in turn are assembled to the cylinder head. These three primary components include a fuel cooler core which is assembled directly to the cylinder head and which includes a fuel inlet, a fuel outlet, and a heat exchanger. The interior of the fuel cooler core is designed for the incoming fuel to flow and circulate across the exterior of the heat exchanger prior to exiting. The second primary component includes a filter head assembly with various inlets, outlets, and passageways. The filter head assembly is attached directly to the fuel cooler core so as to deliver coolant into the heat exchanger.