A method and apparatus for the precombustion identification of a cylinder undergoing compression in an internal combustion engine is disclosed. An electrode gap (e.g., preferably a spark plug) is disposed within a cylinder of an internal combustion engine. The electrode gap is provided with a voltage differential from a power supply through a circuit (preferably an RC circuit). The engine is cranked, and the voltage differential across the electrode gap is monitored during the cranking of the engine. With appropriate choices of the voltage differential across the electrode gap, the resistance R of the circuit, and the capacitance C of the circuit, voltage pulses are produced across the electrode gap during such time when the cylinder is not undergoing a compression stroke. Such voltage pulses are suppressed when the cylinder is in fact undergoing a compression stroke due to a rise in the breakdown voltage across the electrode gap, in accordance with Paschen's Law. The presence or absence of the voltage pulses is preferably converted into a binary output that is indicative of the occurrence of a compression stroke in the cylinder being monitored.
An automotive ignition diagnostic system includes an ion current detection circuit producing a buffered representation of an ion current flowing across an electrode gap of an ignition plug in response to a bias voltage applied thereto. An ignition diagnostic circuit is responsive to the buffered representation of the ion current to charge a single integration capacitor. The diagnostic circuit is operable to produce an output signal having a pulse width defined by the amount of charge on the capacitor. When the ion current flows following a combustion event, the width of the output signal is controlled as a function of the quality of combustion in the corresponding cylinder. However, if sufficient ion current flows prior to combustion, the width of the output signal is controlled to indicate a fouled ignition plug.
A method and a device for detecting the phase of a four-stroke gasoline engine, a gasoline direct injection engine in particular. For reliable phase detection involving relatively little expense during a starting phase, a crankshaft is turned together with at least one piston; ignition is triggered via an ignition coil in at least two successive top dead centers of the piston without a supply of fuel. A primary current or a secondary current, or a primary voltage or a secondary voltage are measured in a measuring period which extends at least over a spark duration after the ignition. From the comparison of the measuring signals of successive ignitions, a conclusion is drawn as to which of the successive top dead centers is an ignition top dead center and which is a charge cycle top dead center.
A sensing element (2) for sensing a fluid (50) composition and a method of using the sensing element (2) are provided. The sensing element (2) includes an electrode base (36) having a first electrode (4) and a second electrode (6) disposed on the electrode base (36); the first electrode (4) and a second electrode (6) being electrically isolated one another except through an external circuitry (64); the first electrode (4) and the second electrode (6) defining a gap (42) between one another such that electrical conduction through a fluid (50) within the gap (42) is proportional to the composition of the fluid.
In a first embodiment, the present invention is a method of detecting an open secondary winding, including the steps of enabling an integrator, resetting the integrator, detecting an ionization current, integrating the ionization current over a spark window, comparing the integrated ionization current with a threshold, and setting an open secondary flag if the integrated ionization current is below the threshold. In another preferred embodiment, the invention is a method of detecting an open secondary winding by measuring spark duration including the steps of comparing an ionization signal with a first threshold, measuring the spark duration when the ionization signal is greater than the first threshold, comparing said spark duration with a second threshold, and setting an open secondary flag.
The present feature of the invention comprises a method and apparatus for determining cylinder ID. When a cylinder is compressed, the resistance increases across the spark plug gap. Thus, if a spark coil is only partially charged before activation of the spark, the air gap is not broken down and no ignition occurs in the cylinder in compression. The failure of a spark plug to spark is reflected in the ionization signal. In a preferred embodiment, the dwell time is selected so that the spark plug located in a cylinder that is not in compression will spark, while a spark plug in a cylinder that is in compression will not. The cylinder in compression will output an ionization signal with a shorter duration than a cylinder not in compression. In a preferred embodiment, two methods are used to calculate the duration of the spark, edge detection and integration.
