Abstract: The subject matter of this specification can be embodied in, among other things, a method that includes receiving a collection of measurements of electric current amplitude in a primary winding of an engine ignition system having the primary winding and a spark plug, identifying an ignition start time, identifying an inflection point based on the plurality of measurements, determining an inflection point time representative of a time at which the identified inflection point occurred, determining a spark start time based on an amount of time between the ignition start time and the inflection point time, and providing a signal indicative of the spark start time.

Abstract: There are provided a signal detection circuit and an igniter capable of enhancing a capability of withstanding breakdown by noise. The signal detection circuit includes an input terminal Sin configured to receive a control signal from an ECU and a bidirectional floating diode provided between the input terminal and a ground. Further, the signal detection circuit includes an attenuation circuit configured to attenuate an output of the bidirectional floating diode, a low-pass filter configured to pass a low-frequency component of the output of the attenuation circuit, and a comparator configured to compare an output of the low-pass filter with a reference voltage.

Abstract: A system according to the principles of the present disclosure includes a vibration intensity module and a stochastic pre-ignition (SPI) detection module. The vibration intensity module determines a vibration intensity of an engine over a first engine cycle and a second engine cycle. The first engine cycle and the second engine cycle each correspond to a predetermined amount of crankshaft rotation. The SPI detection module selectively detects stochastic pre-ignition when the vibration intensity of the first engine cycle is less than a first threshold and the vibration intensity of the second engine cycle is greater than a second threshold.

Abstract: There is provided a combustion state detecting apparatus capable of detecting combustion-state abnormality in an internal combustion engine. A comparison timing is set to be advanced in terms of the rotation angle of the crankshaft of an internal combustion engine with respect to the ending timing of an electric quantity based on an ion that occurs when ignition is performed normally through a predetermined ignition signal among the plurality of ignition signals; in the case where, as a result of the comparison between the detected ending timing of an electric quantity based on an ion and the comparison timing, the ending timing is advanced in terms of the rotation angle of the crankshaft with respect to the comparison timing, it is determined that the combustion based on ignition through the predetermined ignition signal is abnormal.

Abstract: An ON-ignition signal is outputted from an ignition control portion in a period from a posterior time point of the power stroke to an valve opening timing of an exhaust valve so that a capacitor is charged. Then, when it is determined that the maximum value of an ion-output value detected during a negative valve overlap period becomes greater than or equal to a threshold, it is determined that the applied voltage between an center electrode and a ground electrode of a spark plug is dropped. The ON-ignition signal is outputted again to charge the capacitor before the intake valve is opened.

Abstract: A self charging ion current sensing circuit is provided. The self charging ion current sensing circuit is coupled to spark generation circuitry, and utilizes the spark plug electrodes as the ion current sensing electrodes. The self charging is achieved by utilizing the spark current during an ignition event to charge an ion bias capacitor. After the ignition event, the charge voltage build up on the ion bias capacitor is used to provide an ion current across the spark plug gap. The ion current is passed through an offset stage that translates the ion current sense voltage to a voltage that can be buffered and amplified from a single power source available in automotive and vehicular applications. The output of the circuit provides tri-state information, including spark current, null current, and linear representation of ion sense current.

Abstract: A combustion state detection apparatus includes an ion detection device that detects ions generated in a combustion chamber, an end detection device that detects ion signal end timing after spark timing obtained from the ion detection device, and a combustion diagnosis device that sets comparative timing to be compared with the end timing to determine abnormal combustion when the end timing is advanced from the comparative timing. The diagnosis device sets a smoothed value smoothed using various ion signal end timing values to set a ratio of the smoothed value and the spark timing and sets the comparative timing by making the ratio variable at predetermined timing with respect to the smoothed value. Hence, abnormal combustion in the internal combustion engine can be detected without causing a change in detection accuracy even with a change in calibration or environment and matching man hours for abnormal combustion detection can be reduced.

Abstract: Structured with a rotational fluctuation measuring section 51 measuring a rotational fluctuation amount DTdi, a misfire judging section 55 judging a misfire by comparing the rotational fluctuation amount with a judging threshold value, a low load judging section 56 judging an internal combustion engine operating under a low load condition, and an ignition angle judging section 57 judging an ignition angle exceeding an ignition delay angle, wherein the misfire judging section 55 has a map M1 with judging threshold values th1 with respect to rotational speeds ne of the engine and a map M2 with judging threshold values th2 with rotational fluctuation amounts larger than the map M1, and judges the misfire based on the maps M1 and M2 when the engine is operating under the low load condition with the ignition angle exceeding the ignition delay angle and, in other cases, based only on the map M1.

Abstract: An ion-based triple sensor is disclosed. The ion-based triple sensor may include an ion sensing unit, configured to measure an ionic current intensity, a pressure sensing unit, configured to measure a pressure, and a temperature sensing unit, configured to measure a temperature. The ion-based triple sensor may further include a signal processing unit coupled to the ion sensing unit, the pressure sensing unit and the temperature sensing unit. The signal processing unit may include a filtering component, configured to filter at least one of the ion, pressure and temperature measurements, and a data acquisition component, configured to sample the filtered measurements and communicate the samples to a controller.

Abstract: An electrical power system for an engine powered at least in part by a battery having a battery voltage and including a fuel injector and at least one ionization sensor includes at least one common power supply connected to the fuel injector and the ionization sensor and supplying a voltage higher than the battery voltage for operation of the fuel injector and the ionization sensor at least during an ionization sensing period after spark discharge.

Abstract: A probe and method for sensing pressure variations in the exhaust stream of an engine for detecting cylinder misfires. The probe includes a Venturi tube placed in the exhaust stream. The Venturi tube has a sensing tube with an aperture, and the sensing tube is coupled to a pressure sensor for monitoring the pressure of the exhaust stream within the Venturi tube at the point of the aperture. The pressure sensor then generates a voltage signal based on the pressure, and this voltage signal is viewed on an oscilloscope or processed by a microprocessor to generate a waveform readable by a technician. The waveform will indicate the presence of a misfiring cylinder(s), and more specifically, which cylinder(s) is misfiring.

Abstract: A combustion state detecting apparatus for an internal combustion engine includes: an ignition plug (2) for generating a spark discharge for igniting an air-fuel mixture in a combustion chamber; an ignition coil (1) for supplying a high voltage to cause the ignition plug (2) to generate the spark discharge; and an ECU (3) for feeding a driving signal for driving the ignition coil (1). An electromotive force (secondary voltage) due to electromagnetic induction when a primary current is caused to flow through a primary winding of the ignition coil (1) in response to the driving signal from the ECU (3) is applied to the ignition plug (2) to detect an ion current generated in the combustion chamber to detect a combustion state in the ignition plug based thereon.

Abstract: A failure diagnosis apparatus for a vehicle is disclosed. The apparatus includes a diagnosis processing section for executing failure diagnosis processing on a device of the vehicle to generate a diagnosis result. The apparatus also includes a data managing section for managing data of the diagnosis result. After an execution condition is met for failure diagnosis, the diagnosis processing section outputs an execution demand to the data managing section for the failure diagnosis processing. In response to the execution demand, the data managing section outputs an execution permission to the diagnosis processing section for the failure diagnosis processing. Also, after the execution condition is met for the failure diagnosis, the diagnosis processing section starts executing the failure diagnosis processing regardless of whether the execution permission has been outputted by the data managing section. A method of failure diagnosis is also disclosed.

Abstract: In a method for diagnosing an internal combustion engine having first and second fuel injectors, if a misfire is detected, the following steps are performed in sequence: a first fuel quantity of the fuel is introduced only by the first fuel injector; a check is performed to determine whether a misfire results from the introduction of a first fuel quantity in the first step; a second fuel quantity of the fuel is introduced only by the second fuel injector; a check is performed to determine whether a misfire results from the introduction of the second fuel quantity in the third step; and an engine error is diagnosed if a misfire was detected in the second or in the fourth step.

Abstract: An ion-based triple sensor is disclosed. The ion-based triple sensor may include an ion sensing unit, configured to measure an ionic current intensity, a pressure sensing unit, configured to measure a pressure, and a temperature sensing unit, configured to measure a temperature. The ion-based triple sensor may further include a signal processing unit coupled to the ion sensing unit, the pressure sensing unit and the temperature sensing unit. The signal processing unit may include a filtering component, configured to filter at least one of the ion, pressure and temperature measurements, and a data acquisition component, configured to sample the filtered measurements and communicate the samples to a controller.

Abstract: The present invention is a combustion state determination method of an internal combustion engine for detecting an ion current which is generated in a combustion chamber at combustion of the internal combustion engine in a detection period to determine a combustion state, comprising steps of detecting a primary combustion period on the basis of a first ion current which forms the detected ion current and occurs immediately after ignition, detecting a secondary combustion period on the basis of the ion current which occurs after disappearance of the first ion current when at least the detected primary combustion period is normal, determining the combustion state on the basis of the detected primary combustion period when the secondary combustion period is smaller than a predetermined value, and determining the combustion state on the basis of a whole combustion period from start of the detection period of the ion current to end of the last secondary combustion period in the detection period when the secondary