Vauxhall has added a new 1.8-litre 140PS petrol engine to its recently updated Zafira, on sale from July.

Compared to the outgoing model’s 1.8 powerplant, the replacement has 14 per cent more power, consumes four per cent less fuel, has improved flexibility and is even more refined.

With a power output of 140PS, the new 1.8 ECOTEC engine uses advanced valve and cam phasing technology to produce 90 per cent of the 175Nm maximum torque between 2200 and 6200 rpm. This wide range ensures lively performance and exceptional pulling power even at low engine speeds, making everyday driving more relaxed with less need to change gear.

Other innovations include two continuously adjustable camshafts (DCVCP – Double Continuous Variable Cam Phasing) to make the best use of fuel; a two-step intake manifold with a rotary sleeve instead of flaps to minimise flow losses; a highly efficient oil-water heat exchanger; a map-controlled thermostat; and a deep drawn exhaust manifold with an integrated catalytic converter.

Lightweight design also contributes to the efficiency of the engine. In spite of additional features such as DCVCP, the engineers succeeded in making the new unit three per cent lighter than the previous version while achieving increased stiffness and structural strength. The cylinder block alone is 20 per cent lighter than its predecessor due to a hollow frame concept.

Unlike conventional engines, where the crankshaft and camshaft are mechanically linked in a fixed Crank Angle (CA) via a toothed belt or a chain, this engine allows the intake and exhaust cam to twist relative to the crankshaft. This is continuously varied on the new 1.8-litre engine using an extremely compact, lightweight hydraulic vane type phaser.

Depending on the engine’s speed and operating conditions, the valve timing can be selected for optimum performance or fuel consumption. Advantages of the double camshaft adjustment include higher power output and torque characteristics over a wide engine speed range; reduced exhaust emissions thanks to high gas recirculation rates; and reduced fuel consumption using a de-throttled charge cycle.

While the advanced new four-cylinder unit will debut in the Zafira, it will spread to other models in the Vauxhall range in the near future.