Electronically controlled marine diesel engines (e.g. camshaft-less engines such as MAN B&W ME-series and WinGD X-series) replace the mechanical camshaft and fuel pump with an integrated electronic control system that controls fuel injection timing, exhaust valve timing, and cylinder lubrication by hydraulic actuation triggered by solenoid valves commanded by the engine control system (ECU). The three claimed advantages are achieved as follows:

• Variable fuel injection timing: the ECU can advance or retard the start of injection (and vary the injection duration/profile) precisely with load, keeping the maximum combustion pressure (Pmax) at the optimum level over the whole power range, equivalent to an unlimited VIT. This reduces specific fuel consumption (SFOC).
• Precise control of injection quantity/injection pressure: the quantity injected can be set accurately per cylinder, and multi-event injection (pilot/pre/post) can be used to optimise combustion; the injection profile can be shaped to reduce heat loss and improve thermal efficiency.
• Optimised exhaust valve timing: the exhaust valve opening/closing timing can be varied to control the effective compression/expansion and to optimise the Miller effect and scavenging, reducing pumping losses and improving efficiency.
• Load-dependent cylinder deactivation (on some engines): at low load, some cylinders are cut out (no fuel) while the rest take the load, keeping the remaining cylinders at high load where specific consumption is lower, improving part-load economy.
• Balanced cylinder output: load balancing between cylinders to even out temperatures and maximise efficiency and reliability.

• The precise and variable injection timing, injection shaping (pilot injection), and exhaust valve timing allow the combustion to be tuned to lower NOx (by reducing local peak flame temperatures, e.g. by retarding injection or by the Miller effect/late inlet valve closing) and to lower smoke and particulate.
• Fuel injection can be adapted to operating conditions and to exhaust gas treatment (e.g. to keep the exhaust temperature high enough for a downstream SCR system at low load, or to work with the EGB/exhaust waste heat recovery).
• Because injection timing can be set individually per cylinder, the engine can run with consistent low emissions across cylinders and loads.
• Combined with the ECU the engine can be adjusted to meet the required NOx (Tier II/Tier III) and to give lower SOx smoke when burning various fuels.
• Camshaft-less engines also allow flexible cylinder lubrication (electronic lubrication) to minimise oil consumption and deposits, and can be adapted to synthetic/gas fuels.

• Because there is no camshaft to be shifted and no fuel pump drive to be reversed, the direction of rotation can be changed almost immediately: the ECU simply switches the firing order and controls the valves and injectors, so reversal is fast.
• Starting air consumption is reduced because the injection can begin at the correct instant on the down-stroke, and the engine can be started more efficiently using electronic control of the starting sequence.
• Rapid load acceptance: injection timing and quantity can be advanced before the load is applied, giving fast torque response, so acceleration and deceleration (crash manoeuvres) are quick and controllable.
• The hydraulic system provides instant actuation, and the controls avoid the delays of mechanical reversing gear, so the time to go from ahead to astern is minimised and the manoeuvre is safer and smoother.

These features together give better fuel economy, lower emissions and markedly better manoeuvring performance than camshaft-controlled engines.