New Mitsubishi MIVEC engine slashes fuel consumption

MITSUBISHI Australia is considering the case for an all-new 1.8-litre petrol engine for next-generation vehicles, including the forthcoming successor to the Colt light car, following its Japanese parent’s announcement overnight of an engine achieving a significant improvement in fuel economy.

The new ‘4J10’ 1.8 MIVEC (Mitsubishi Innovative Valve timing Electronic Control) engine will debut in Japan this month in the ASX compact SUV, Lancer small sedan and Lancer Sportback.

It could provide the backbone of a potential hot-hatch variant of the Colt replacement – dubbed ‘Global Small’ for now and not due for release in Australia for “in excess of 12 months”.

Mitsubishi Motors Australia head of corporate communications Lenore Fletcher told GoAuto that the new-generation engine and related technology such as an upgraded engine idle-stop system would be considered for future models here, particularly redesigned vehicles such as the Colt successor, which to date has only been linked with smaller 1.0 to 1.2-litre powertrains.

“You won’t see that (1.8 MIVEC) in any actual model vehicle until we start to see the new wave of all-new vehicles come through,” Ms Fletcher said. “We’re looking to Global Small, things like that, in that generation of vehicles.

“There is a wave of new vehicles coming, which will start in the next 12 to 18 months.

“Will it (the engine) be for here in Australia? You’d probably think so ... We’ll be looking closely at whatever is available.”

Left: The new MIVEC engine. Below: ASX and Lancer sedan.

Ms Fletcher acknowledged its emergence in the ASX and Lancer overseas indicated the potential for future versions of these models to pick up the new engine, which is a compact and lightweight 1.8-litre single-cam 16-valve four-cylinder featuring a new version of the company’s MIVEC variable valve-timing system and the latest version of its AS&G (Auto Stop & Go) idle-stop system.

The idle-stop system has been developed for use on models fitted with a continuously variable transmission (CVT).

Mitsubishi claims the new single-cam MIVEC system combines with improved “combustion stability” and a reduction in piston friction to reduce fuel consumption without sacrificing power and torque over the current twin-cam ‘4B10’ unit currently in service.

The 1798cc engine produces 102kW of power at 6000rpm and 172Nm of torque at 4200rpm, all the while offering a claimed 12 per cent improvement in fuel economy for the ASX and Lancer.

Australian-spec ASX and Lancer sedan and Sportback models include in their powertrain line-up a 2.0-litre engine, developing 110kW/197Nm in the compact SUV – good for 7.9L/100km in 2WD CVT form – and 113kW/198Nm and 8.3L/100km (CVT) in the small-car series.

The ageing Colt, which is not available in Victoria due to its lack of electronic stability control, uses a 77kW/141Nm 1.5-litre engine and is capable of 5.6L/100km mileage with a CVT.

The current 4B10 MIVEC system varies the valve opening timing on a continuous basis, while other MIVEC systems currently employed by Mitsubishi switch between different valve lifts and valve opening durations according to engine speed.

“The new MIVEC system employed in the new 4J10 engine can do what the previous two systems could do – but at the same time, all the time,” said Mitsubishi.

“This is due to a single mechanism that mechanically couples intake valve lift, opening duration and timing, allowing these three parameters to be varied simultaneously and continuously.

“As a result, the new system provides ideal valve operation control that also reduces ‘pumping losses’ by using intake valve timing to control intake volume, thereby further improving fuel economy.”

The company claims the switch to a single-cam set-up enabled it to reduce both engine weight and size due to the reduction in components.

The idle-stop system, meanwhile, has a new control unit that integrates with the 4J10 engine, CVT transmission, electronic stability control and climate-control air-conditioning.

It also uses a more durable 12-volt battery and a DC/DC converter to improve stereo operation and prevent the onboard satellite-navigation system (if fitted) from resetting itself when the engine restarts.

According to Mitsubishi, the combination of the new MIVEC engine and idle-stop system provides AS&G CVT-equipped models with “quick engine restart and initial acceleration performance that feels no different from a car without AS&G”.

“In addition, fuel efficiency is improved because the new MIVEC engine allows the engine to restart using less intake air and fuel by keeping a low valve lift at engine restart,” the company said.

“The new AS&G also controls brake force from engine stop to restart via the car’s integrated control system. This means that the car will remain stopped on inclines until power is applied to the wheels.”

The powertrain announcement stems from Mitsubishi’s current mid-term business plan that calls for a 25 per cent reduction in on-road CO2 emissions of new vehicles in 2015, compared to the average in 2005.

To achieve its goals, Mitsubishi said it is “aggressively moving forward with development of technologies like the new MIVEC and new AS&G systems to improve fuel economy in internal combustion engines, increasing the number of models powered by ‘clean diesel’ engines that meet the latest emissions regulations in Japan and Europe, and further advancing its gasoline engine technology”.

It is also pushing ahead with the development and rollout of full-electric and plug-in hybrid vehicles, including i-MiEV and derivatives, and a plug-in hybrid version of its next-generation Outlander due in 2013.