Lucas Industries Public Limited Company

Michael Holmes

Benjamin J Bradshaw

John M Ironside

Russell Wilson Jones

Anthony C Wakeman

Stephen W Caddy

Simon C Barnard

Variations in the speed of an internal combustion engine are measured and the distribution of the variations is analyzed for asymmetry, which indicates engine misfire. A threshold is generated as a function of engine speed increases and compared with engine speed decreases to detect asymmetry in the distribution.

Method of and apparatus for analyzing internal combustion engine speed

In order to detect misfire in an internal combustion engine, engine speed is determined by measuring the time of passage of a crankshaft disc from a first position to a second position during every revolution. A detection circuit takes the reciprocal of the measured times of passage to form a series of engine speeds and forms the difference between consecutive engine speeds. These differences are compared with a threshold to signal a misfire when the threshold is exceeded.

Method of and apparatus for detecting misfire

An adaptive control system for an internal combustion engine has a mixture control device and an ignition timing control device. Combustion performance, such as engine roughness is measured and mixture varied about a base value to achieve a desired performance. Ignition timing is compensated for the mixture variation by perturbing ignition timing about a base valve, detecting the slope of engine output with respect to ignition timing and varying the timing to achieve a desired slope.

Adaptive control system for an internal combustion engine and method of

Disclosed is a method and apparatus for controlling an internal combustion engine having two inputs and one output affected by both inputs. One input is perturbed and the effect on the output is compared with a desired effect on the output. One or the other input is varied until the actual affect on the output is the same as the desired effect on output. In one embodiment, ignition timing is periodically varied and the effect upon engine speed is detected. The detected output variations (slope) are compared with predetermined output variations for the existing engine speed and load demand. Any error is used to correct fueling to the engine. Preferred embodiments include unique slop determination as well as a unique interpolation method of determining the engine input from a fixed schedule. In a further embodiment the error corrects the ignition timing directly and corrects fueling indirectly at a slower rate. Further embodiments control air/fuel ratio, engine roughness, exhaust gas recirculation, for individual cylinders or groups of cylinders or the engine as a whole, depending upon the change in engine output in response to the variation in engine input.

Method and apparatus for controlling an internal combustion engine

An engine control and combustion quality detection system and method are provided for an internal combustion engine having at least one control input such as spark advance angle or air/fuel ratio. A base value is established for the control input and the control input is periodically perturbed about the base value. A sensor senses an engine parameter such as knock or engine roughness representing the combustion quality of the engine and provides an output representing this engine parameter. A slope calculation device receives the output from the sensor when the control input is being perturbed about the base value and determines the slope or differential of the output from the sensor to determine the engine parameter as a function of the control input, thereby to provide an indication of combustion quality of the engine. By determining the combustion quality of the engine by calculating the slope of the sensor output when the perturbation device perturbs the first control input about the established base value, the noise component of the sensor output is substantially eliminated. The slope of the sensor output should be at or close to zero when combustion quality is acceptable.

Method and apparatus for engine control and combustion quality detection

Disclosed is a method and apparatus for controlling an internal combustion engine having two inputs and one output affected by both inputs. One input is perturbed and the effect on the output is compared with a desired effect on the output. The other input is varied until the actual affect on the output is the same as the desired effect on output. In one embodiment, ignition timing is periodically varied and the effect upon engine speed is detected. The detected output variations are compared with predetermined output variations for the existing engine speed and load demand. Any error is used to correct fueling to the engine. In a further embodiment the error corrects the ignition timing directly and corrects fueling indirectly at a slower rate. Further embodiments control air/fuel ratio, engine roughness, exhaust gas recirculation, for individual cylinders or groups of cylinders or the engine as a whole, depending upon the change in engine output in response to the variation in engine input.

An ignition system with an ignition coil employs a power amplifier driven by a microprocessor for starting and interrupting coil current, in accordance with signals from an engine driven transducer. The power amplifier includes a current limiter, but this does not usually come into operation. Instead, the actual current flowing just before the instant of spark in each engine cycle is measured and the on time of the power amplifier is adjusted for the next cycle to cause the final current to approach a desired value less than the current limit value.

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Solihull, United Kingdom

Michael Holmes