Considering that diesel sales for passenger cars are mainly concentrated in Europe, and that a new diesel engine requires significant development work, we came to the conclusion that in this instance, the best solution was to cooperate with another OEM (Original Equipment Manufacturer) rather than develop a unit ourselves.

—Gerald Killmann, Vice President R&D at Toyota’s R&D center in Belgium

2014 Verso. Click to enlarge.

Diesel engine sales continue to dominate the European market in the C-MPV segment, and 1.6 liter variants currently account for more than 50% of sales. 20 kg lighter than the prior 2.0 D-4D powerplant, the Euro 5 compliant 1.6 D-4D engine develops 112 DIN hp/82 kW at 4,000 rpm and 270 N·m (199 lb-ft) of torque from 1,750 to 2,250 rpm. It accelerates the Verso from 0-100 km/h in 12.7 seconds, and on to a top speed of 185 km/h (115 mph).

The engine delivers an 8% improvement in fuel efficiency over the 2.0 D-4D unit, equating to fuel consumption of 4.5 l/100 km (52.3 mpg US) in the combined homologation cycle. Simultaneously, CO₂ emissions have reduced from 129 to 119 g/km.

These figures are supported by the first adoption of a Stop & Start system in the Verso range.

Several engineering challenges were key to the successful integration of the new 1.6 D-4D engine, Toyota said. All electrical interfaces were redesigned, and a newly-developed dual-mass flywheel was fitted to optimise noise and vibration. New engine mounts offer particularly low vibration characteristics, especially under Stop & Start operation, minimizing Noise, Vibration and Harshness (NVH) and offering quiet running at cruising speeds.

The engine itself has been tuned to deliver a fast throttle response throughout the rev range. It generates good initial response at low rpm, then, as turbo boost develops, provides a linear torque build-up. The availability of torque has also been stretched, so the engine will happily rev beyond 3,000 rpm without running out of breath.

With a low displacement engine in a relatively big car, it’s essential that the engine delivers. So that was one of the key engineering targets. We had to make sure that torque was available from low revs, but also that it was spread over a wide rev band. This ‘stretchiness’ was one of our key goals—it allows the driver to stay in the same gear for longer, at higher rpm during acceleration, without getting the feeling that the engine runs out of steam.

A second item was fast engine response, delivering sufficient torque even before the turbo cuts in. And not just a fast response but also a natural torque build-up, so it doesn’t feel like small engine... small engine... small engine... and then suddenly the turbo comes in with a whoosh. Rather, we wanted a more natural, linear torque build-up. As a result, the driver gets access to very decent performance, without upsetting the comfort of his passengers with sudden bursts of acceleration as he goes through the gears—important in a family car!

The target on NVH was to be as good as the 2.0 D-4D and, in some areas, perform even better. And of course, one of the key objectives was efficiency. We managed to cut back CO₂ emissions by 8%, from 129 to 119 g/km, compared to the 2.0 D-4D engine. And due to the smaller engine size and the adoption of a Stop & Start-system, the fuel consumption advantage is noticeable, especially in urban conditions.

—Gerald Killmann

With ride quality already assured on the existing Verso, spring settings have been modified for the new 1.6 D-4D version to replicate the same levels of body control and ride comfort.