Abstract: A fuel injector control method comprises determining a required separation time between a termination of an on signal associated with a first injection event and an initiation of an on signal associated with a second injection event. The method comprises calculating an overlap time between the separation time and the time to charge the piezoelectric stack to a first level; dividing the overlap time into first and second time periods as a function of the charge and discharge currents; applying the charge current to the piezoelectric stack for a charge time; and applying the discharge current to the piezoelectric stack for a discharge time so as to discharge the stack to a second level, wherein the discharge time is calculated on the basis of the second time period of the overlap time. Thus, first and second injection events are merged in a pulse mode of operation.

Abstract: A fuel injector control method comprises determining a required separation time between a termination of an on signal associated with a first injection event and an initiation of an on signal associated with a second injection event. The method comprises calculating an overlap time between the separation time and the time to charge the piezoelectric stack to a first level; dividing the overlap time into first and second time periods as a function of the charge and discharge currents; applying the charge current to the piezoelectric stack for a charge time; and applying the discharge current to the piezoelectric stack for a discharge time so as to discharge the stack to a second level, wherein the discharge time is calculated on the basis of the second time period of the overlap time. Thus, first and second injection events are merged in a pulse mode of operation.

Abstract: A collapsible frame structure for the body of a child's push chair has a pair of side frames between which a collapsible X-frame is pivotally connected. Each side frame has when erected, a pair of upright members and two diagonal members which are pivotally connected to the upright members adjacent their ends. The diagonal members have a pivotal interconnection and each diagonal member has a hinge between this pivotal interconnection and one of the pivotal connections between each diagonal member, and an upright member. Toggles are provided for maintaining the X-frame extended. Extensions of the respective diagonal members provide handles for the push chair and a support for the back of a fabric chair.