The Lucas Electrical Company Limited

Lucas Industries Limited

Peter H Salway

Richard G Woodhouse

A fuel injection timing system for a compression ignition engine makes use of a read only memory programmed to provide a digital output representing the time or shaft angle when injection is required in accordance with the values of digital input corresponding to speed and engine load. The speed data is obtained from a transducer which also provides position signals enabling an injection datum to be established so that a comparator can compare the output of the memory with a digital signal representing shaft angle or time to trigger injection at the required instant.

Fuel injection systems for internal combustion engines

A device and method for measuring the rate of change of a pulse train from a transducer includes first counter which counts the number of pulses in a first fixed frequency of pulse train during each interval between the signal pulses. A divider receives the count generated in the preceding interval and divides the frequency f.sub.1 of a second fixed frequency pulse train by this count. This divided pulse train is counted by a second counter for the duration of each interval to provide a ratio of the change in duration to the preceding interval's duration.

Acceleration sensor

A solenoid control circuit includes a first switching element which connects one side of the solenoid load to earth via a current sensing resistor. The other side of the solenoid load is connected by a second switching element to a supply rail. This second switching element is biased to conduct but can be turned off by either of two comparators which are connected to compare the voltage across the current sensing resistor with two different reference voltages. Each comparator has hysteresis and the circuit operates so that one comparator operates to switch off the second switching element when a predetermined current level is reached and the other comparator operates to switch the second switching elements on and off at lower current levels between said predetermined current level and the lower threshold level of the first comparator.

Control circuits for solenoids

A spark ignition system for a vehicle has a memory device receiving inputs representing engine parameters and producing an output representing the crankshaft position at which a spark is to be produced. This output is compared with a signal representing the actual crankshaft position starting from a datum position, and a common transducer is used to provide the required engine speed signal and crankshaft position signal.

Spark ignition systems for internal combustion engines

In a spark ignition system it is possible for a vehicle to stall with the contact breaker closed, and for a transistor or other device in series with the ignition coil to conduct heavily. This problem is overcome by limiting the time for which the ignition coil can be energised.

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Birmingham, United Kingdom

Peter H Salway