No timing chain
Another case in point is electromechanical valve control. In today's engines, a camshaft acts on the valve stems to open and close the valves. As the crankshaft drives the camshafts through gears or a chain or belt, the timing of the valves' openings and closings is controlled by the cam design, and is fixed relative to piston position. This means that engine performance (in terms of emissions or fuel economy) is optimal over only a narrow range of engine speed.
If the valves were electromechanically actuated, however, they could be opened and closed without regard to crankshaft position. They could operate optimally at all engine speeds, torque levels, temperatures, and any other variables the designer includes. In fact, valve timing could be made part of a closed-loop emission-control system.
Moreover, an electromechanical system would eliminate the heavy and complicated camshafts and timing chains or gears. The valves would be actuated by sending current pulses through spring-loaded solenoids with the valve stems as their cores.
Electromechanical valves offer other interesting possibilities. For example, the valves can all be opened at the beginning of engine start-up, relieving compression and greatly reducing the cranking torque needed, so that smaller batteries and starter motors could be used. In fact, the peak power of the starter motor might be close to that of the alternator, so that a combined starter/alternator might become feasible. The starting torque might even be so low that the engine could be turned over through the fan belt at start-up, and the combined starter/alternator could then simply be mounted in the place now occupied by the alternator.
Start without moving
Even more intriguing, when combined with direct fuel injection, electromechanical valves may be able to start an engine statically, with no initial rotation whatsoever. Valves to the appropriate cylinders would be closed, and fuel would be injected into them and ignited, turning over the engine. If static starting should prove feasible, the battery could be designed for energy storage only, not for cranking power, and its size could be much reduced.
Another new kind of load, the electrically heated catalytic converter, is a direct response to environmental concerns and mandates. The electric heater will get the catalytic converter up to temperature quickly, which is important because a converter can reduce nitrogen emissions only when it is hot; the electric heater ensures that it gets hot within a few seconds after engine start-up instead of the many minutes required for heating by exhaust gases. In fact, one proposal calls for preheating the catalytic converter from a dedicated battery before start-up. Such heaters could eliminate a large source of pollution--emissions from cold engines.